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  • 1995-1999
  • 1985-1989  (695)
  • 1890-1899
  • 1988  (695)
  • Inorganic Chemistry  (639)
  • Industrial Chemistry
  • Nuclear reactions
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  • 1995-1999
  • 1985-1989  (695)
  • 1890-1899
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Masthead (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110101
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  • 2
    Electronic Resource
    Electronic Resource
    Axial pressure profile in circulating fluidized beds (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 11-17 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Design and operation of a circulating fluidized bed requires the knowledge of fluid mechanics. According to heat and mass transfer as well as chemical reactions, the effect of the set superficial gas velocity on the axial pressure profile is of particular interest. The axial pressure profile was measured for a variety of solids, as a function of the superficial gas velocity, in a cylindrical circulating fluidized bed with an inner diameter of 0.19 m and an overall height of 11.5 m. Depending on the solids content and superficial gas velocity, two or one sections can be observed in the plant where the pressure gradient is constant. A pressure profile with one pressure gradient exists only at high gas velocities, so long as the acceleration pressure drop immediately above the gas distributor is negligible. Comparison of measured pressure drops in circulating fluidized beds with those measured in vertical pneumatic conveying led to a state diagram for vertical gas-solid flows. The operation behaviour of different types of circulating fluidized bed plants can be explained with the aid of this diagram.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110103
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  • 3
    Electronic Resource
    Electronic Resource
    Engineering aspects and applications of crossflow microfiltration (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 17-25 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Crossflow microfiltration (CMF) is a pressure driven membrane process for the separation of suspended microparticles, bacteria and emulsion droplets. The fluid to be filtered flows in parallel to the membrane surface and restricts the formation of a filter cake. This contribution explains the basic process characteristics and the combination of the crossflow technique with other membrane cleaning methods (periodic backflushing, chemical cleaning). Special attention is paid to the influence of different process parameters on the flux through the membrane. The principle of plant design and different operation modes are described. Engineering aspects such as hydrodynamics, energy requirement and selection of construction materials are discussed in some detail.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110104
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  • 4
    Electronic Resource
    Electronic Resource
    Mass transfer contributions of solid particles to gas permeation in viscous laminar tube flow (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 25-31 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: While two- and multiphase flows find more and more application in chemical engineering practice, and the demand for theoretical information about mass and heat transfer processes in such systems is increasing, such data or at least experimental results which could be generalized are still lacking. The following pages are concerned with mass transfer in laminar suspension tube flows normal to the main direction of flow due to the individual motions of small, inert spherical particles. On the basis of a large number of experimental data, an interpretation is attempted of the role of nearly neutrally-buoyant particles in mass transfer enhancement, and a model for a semi-empirical description is suggested. The experimental arrangement uses the mass transfer of carbon dioxide in laminar flow of salt water during the process of gas permeation through a permeable membrane tube wall.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110105
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  • 5
    Electronic Resource
    Electronic Resource
    Heat transfer between particle beds and submerged surfacesPaper presented by O. Molerus at the “Jahrestreffen der Verfahrens-Ingenierue”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 126-138 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Theoretical modelling of heat transfer to particle beds comprises two sequential steps: transfer from the heating surface to contacting particles followed by transfer to the interior of the bed. Two different limiting case can be formulated for the second step: unmixed and homogeneously mixed bed. In the case, heat is transferred gradually via a repeated sequence of heat transfer in the gap between adjacent particles and conduction in the particulate material. In the second case, heat is transferred to the interior of the bed by mixing of particles which have previously attained the temperature of the heating surface. On the other hand, the mixing motion maintains a homogeneous lower temperature throughout the bed. Theory predicts a significant and easily measurable difference in the behaviour of heat transfer coefficients for the two regimes at long contact times t: unmixed beds ∝ \documentclass{article}\pagestyle{empty}\begin{document}$$ \sqrt t $$\end{document} and homogeneously mixed beds ∝ 1/t. For short times t, both regimes show the same behaviour, namely of t.From a theoretical standpoint, it makes sense to differentiate further between the behaviour patterns of unmixed beds: at long times t, instantaneous heat transfer coefficients are independent of heat transfer form the heating surface to adjacent particles. Comparison with experimental result from literature shows that the derived models, which are consistent, are suitable for describing the heat transfer from submerged surfaces to unmixed and mixed beds of particles.
    Additional Material: 24 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110118
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  • 6
    Electronic Resource
    Electronic Resource
    Scale-up of bioreactors for fermentation of mammalian cell cultures with special reference to oxygen supply and microcarrier mixingPaper presentet by J. Vorlop at the “Jahrestreffen der Verfahrensingenieure”, September 17 to 19, 1986 in Strasbourg (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 171-178 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The increasing demand for products from mammalian cells has prompted the authors to develop a new type of bioreactor. Its significant features include the supply of oxygen, homogeneous distribution of microcarrier suspensions and process control. Media with high protein contents, required for mammalian cell cultures tend to generate foam. This causes the flotation of solid particles. The reactor was equipped with a system of porous hydrophobic Accurel hollow fibre membranes in order to prevent the formation of bubbles. The membrane is coiled in the form of a basket, or fixed on several carriers. If the liquid pressure is higher than that of the gas phase inside the membrane, a bubble - free oxygen supply to the culture broth can be achieved. The problem of axial mixing of microcarier suspensions was solved by the use of a spiral agitator, attached underneath the aeration system at the bottom of the reactor. The combined aeration and mixing system, which is driven by an eccentric motor, undergoes a tumbling motion. Sufficiently homogeneous suspensions are produced in this system at low membrane velocities, i.e. in presence of low shear forces.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110123
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  • 7
    Electronic Resource
    Electronic Resource
    Organosolv delignification of southern pine - an alternative pulping process (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 195-199 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aqueous ethylenediamine-ethanol-anthraquinone (EDA-EtOH-AQ) pulping of Southern Yellow Pine was studied for lignin removal and pulp yield. Temperature, time and ethylenediamine concentration in the solvent solution were studied and equations for lignin content and lignin-free yield were developed. Lignin content is decreased by an increase of temperature, time or EDA concentration. Lignin-free yield of pulp decreased with an increase in temperature or time, but increased with increasing EDA concentration. Overall, the solvent is selective, that is, large quantities of lignin are removed while the retention of cellulose remains high.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110126
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  • 8
    Electronic Resource
    Electronic Resource
    Consistent scale-up procedure for the power consumption in agitated non-newtonian fluids (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 199-205 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It is shown how a consistent scale-up rule for the power consumption in agitated non-Newtonian liquids can be obtained. The new approach is based on the concept of including the real liquid in a set of liquids with similar rheological properties and of using, in a small scale laboratory system, a suitable member of that set instead of the original liquid. Considerations of similarity lead to simple unique selection rules for the actual test liquid and for the stirrer speed in the laboratory experiment as well as to a prediction of the power requirement in the real system. The theory is tested experimentally by means of different aqueous polyacrylamide solutions. The results are compared with predictions, according to Metzner and Otto as well as Rieger and Novák.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110127
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  • 9
    Electronic Resource
    Electronic Resource
    Bubble column research in Japan (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 205-212 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Many experimental studies on the bubble column have been reported by Japanese researchers since around 1960. They include studies of bubble behaviour, bubble size distribution, transition from the homogeneous bubbly flow regime to the heterogeneous liquid circulation regime, liquid velocity distribution, longitudinal liquid mixing, hydrodynamic modelling, the gas holdup, and the volumetric coefficient of gas-liquid mass tranfer kLa. Studies covered various modified bubble columns, such as the airlift reactor with an external or internal loop, the packed bubble column, and others. Performance of three-phase bubble columns, which deal with suspensions or emulsions, and their use as bioreactors or chemical reactors were also studied.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110128
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  • 10
    Electronic Resource
    Electronic Resource
    A model-based control system for a distillation columnPaper presented by F. F. Rhiel at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 188-194 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A control concept which includes an adaptive multivariable control algorithm and an observer model has been put into practice in the operation of a distillation column which separates water from a solvent. The model yields predictions of solvent concentration in the waste water which forms the top product. Early detection of disturbances permits an adjustment of the process in time. This has resulted in an exceptionally smooth operation of the column, with a drastic reduction in solvent concentration fluctuations, observed with conventional control technology. Since the only measurements required are pressure, temperature and the rate of flow, this control system is largely free from disturbances. In addition to considerably reducing the burden on operating personnel, use of this control system has lowered the costs of waste water treatment, solvent losses, analysis expenditure and energy consumption.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110125
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  • 11
    Electronic Resource
    Electronic Resource
    Development of design charts for fixed-bed adsorptionPaper presented by W. Otten at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, Spetember 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 289-297 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model of the dynamic behaviour of non-isothermal fixed-bed adsorbers has been developed which takes into account the various mass and heat transfer resistances. Comparison of experimental and simulated results confirms that the model can predict the adsorption and desorption breakthrough curves of an adiabatically operated column, using only equilibrium data and tortuosity factors obtained from single pellet experiments. A simplified model with a reduced number of parameters was derived by investigation of the dimensionless transfer parameters under industrial conditions. It becomes evident that the main transfer mechanisms are convective heat and mass transfer in the bulk flow and diffusion within the pores of the particle. Dimensionless effluent concentration is expresses in terms of dimensionless time, a transport parameter, a non-isothermal parameter, the adsorption equilibrium and the inlet and initial concentrations and temperatures in the simplified model. For a chosen system of adsorbate and adsorbent, design charts can be developed by computer simulation, to determine graphically the breakthrough time as a function of significant process parameters, i.e. the dimensionless transfer parameter and the feed concentration.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110138
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  • 12
    Electronic Resource
    Electronic Resource
    The role of energy dissipation in contacting and mixing devicesPresented in memory of Professor Otto Nagel, at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 276-287 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The aim of the present paper is the discussion of the relevance of power dissipation as a criterion for the understanding and prediction of transfer and mixing efficiencies in contactors and chemical reactors. After reviewing the approach of Le Goff to the energetic efficiency of exchangers, based on the deviations from Chilton-Colburn analogy, the following processes are studied: mass transfer between a flowing fluid and a reactive solid surface, transfer to a fixed object in a stirred vessel, macro- and micromixing of miscible fluids, and mass transfer in fluid-fluid contractors (especially gas-liquid reactors). It is concluded from the various examples that a direct relationship between the dissipated power and intensity of transfer or mixing can be established only under the two following conditions: local values must be considered at the point where the actual transfer and mixing occur, and not average values over the whole device, and power dissipation must be coupled to transfer or mixing and appear physically as the driving force of the process.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110137
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  • 13
    Electronic Resource
    Electronic Resource
    Subcooled boiling heat transfer to R 12 in an annular vertical channel (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 320-327 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Detailed knowledge of the physical phenomena involved in subcooled boiling is of great importance for the design of liquid-cooled heat generating systems with high heat fluxes. Experimental heat transfer data were obtained for forced convective boiling of dichloro-difluoroethane (R 12). The flow is circulated upwards through a concentric annular vertical channel. The inner and outer diameters of the annulus are 0.016 m and 0.03 m respectively. The reduced pressures studied were 0.24 ≤ p/pcrit ≤ 0.8, inlet subcooling varied from 10 to 75 K and mass fluxes from 500 to 3000 kg/m2s, which corresponds to Re numbers from 30000 to 300000. The experiments, described in this study, demonstrate that liquid fluorocarbons show certain unusual boiling characteristics in the subcooled flow, such as hysteresis of the boiling curve. These characteristics are attributed to the properties of the fluid, mainly the Pr number and the very low surface tension. The pronounced boiling curve hysteresis can be explained by the fact that large nucleation sites may have been flooded prior to incipient boiling. A dimensionless regression formula is presented which predicts the onset of subcooled boiling as a function of reduced pressure (p/pcrit), Boiling-(Bo), Reynolds-(Re), and a modified Jacob number (Ja), over the whole range of parameters studied, with a good accuracy, including water data from literature.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110142
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  • 14
    Electronic Resource
    Electronic Resource
    Mass transfer behaviour of gas-liquid jet loop reactorsPaper presented by M. Geisendörfer at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987.Dedicated to Professor Dr. Horst Langemann on the occasion of his sixtieth birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 306-311 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A special type of jet loop reactor (JLR), designed for continuous operation and short residence times was investigated with regard to its mass transfer behaviour, described by the volumetric mass transfer coefficient kLa. The jet stream and superficial gas velocities are varied in two JLRs of different sizes, equipped with different nozzles. Fully desalinated water, 0.08 molar NaCI solution and solutions of different concentration of carboxymethyl cellulose (CMC) are used as the liquid phase. A steady-state physical method is employed to determine kLa: air oxygen is purged from the liquid phase by gaseous nitrogen. The measurements show that the reactor is characterized by high power density and high mass transfer performance. No limit of mass transfer capacity was observed in the chosen ranges of volumetric gas and liquid flow rates, i.e. at a given jet stream velocity, the relationship between kLa and the superficial gas velocity is nearly linear. The investigations show that the mass transfer contributed by the jet stream largely depends on liquid phase composition.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110140
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  • 15
    Electronic Resource
    Electronic Resource
    Characteristics of solid suspensions in a bubble column without and with draft tubePaper presented by J. Heck at the “Jahrestreffen der Verfahrensingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 335-340 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In order to investigate the suspension behaviour of solid particles in bubble columns without and with draft tube, minimum gas velocities for generating and maintaining complete solid suspension were determined. Experiments were carried out in a bubble column with a diameter of 200 mm and a height of 2 500 mm. The bubble column could be equipped with a draft tube with a diameter of 120 mm and a length of 1 500 mm. The state of suspension was determined by measuring the hydrostatic pressure as a result of suspended solid particles with an inductive pressure gauge. Solid content εs, solid density ϱs, particle size dp, particle shape, particle size distribution, and solid wettability were varied. Furthermore measurements of integral gas holdup were carried out.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110144
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  • 16
    Electronic Resource
    Electronic Resource
    Modelling of multiphase detonations with drop disintegration - description of thermal detonations (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 327-334 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A model is presented which consists of steady-state and transient codes for the description of reacting multiphase flow fields, including hydrodynamic fragmentation of liquid drops in relative flows. An application of this model for the description of large scale melt-coolant interactions (thermal detonations) is described. A simulation of two-phase chemical detonations, especially those with hydrodynamic disintegration of liquid fuel drops in the reaction zone, is possible, in principle, within the framework of the modeling.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110143
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  • 17
    Electronic Resource
    Electronic Resource
    Modelling of a pressure swing adsorption process for oxygen enrichment with carbon molecular sievePaper presented by E. Richter at the “Jahrestreffen der Verfahrens Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 341-351 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Adsorptive separation of oxygen from nitrogen and argon is carried out during the desorption steps of a pressure swing adsorption (PSA) process which uses carbon molecular sieves developed by Bergbau-Forschung GmbH. The adsorption isotherms of the three main components of air are very similar. On account of the pore size distribution of CMSN2, the diffusion coefficient of oxygen is more than eight times those of nitrogen and argon so that air separation occurs by adsorption kinetics. Experimental results for the individual steps and cyclic operation of the PSA process are presented and compared with the predictions of an isothermal plug-flow model. Adsorption rate is represented by a linear driving force equation. If the diffusion coefficients are adapted separately to every step, a good agreement is observed between the model calculations and experimental results.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110145
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  • 18
    Electronic Resource
    Electronic Resource
    The importance of corrosion prevention for the safety of chemical plants (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 359-365 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: One of the most important tasks to eliminate dangers in chemical plants is the prevention of corrosion. This implies the provision of safe enclosures and reaction spaces for the substances to be processed. The present contribution deals with the procedure in the selection of materials for equipment exposed to corrosion and stresses the difficulties connected with the elimination of local corrosion. The relevance of prevention of crack forming corrosion processes is emphasized. Problems to be solved in order to obtain results from investigations, suitable for a safe application of a materials under practical conditions, are indicated.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110147
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  • 19
    Electronic Resource
    Electronic Resource
    Modelling of activated carbon desorption by a circulated inert gasPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987 (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 352-358 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The adsorption solvent recovery process, known as Recursorb which involves desorption and cooling steps by a circulated inert gas, is analyzed in detail on the basis of equilibrium theory. Employing the method of characteristics, the model is solved for each step of the overall process. The estimations confirm that the process performance with respect to final gas purity, activated carbon useful capacity and operation times depends on condenser and heater temperatures. Simple expressions are derived for the calculation of adsorption, desorption and cooling times.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110146
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  • 20
    Electronic Resource
    Electronic Resource
    Decoking of fixed-bed catalytic reactorsDedicated to Prof. Dr. Hanns Hofmann at the ocassion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 367-375 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model for the description of the non-steady state process of decoking of a fixed bed catalytic reactor is presented. The relevant dimensionless groups are identified and their influence on the process discussed. Appropriate relationships are given for the estimation of the maximum temperature in the bed. Methods of monitoring the process and of controlling it in the case of unknown or variable coke contents are explained.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110148
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  • 21
    Electronic Resource
    Electronic Resource
    Model discrimination and parameter estimation in the kinetic study of methanol synthesisDedicated to Professor Dr. Hanns Hofmann on the occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 375-383 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The new model discrimination method is based on the correlation coefficient test of experimental data sets for different reactions, without requiring a prior parameter estimation. The new parameter estimation method reduces by n the number of dimensions to be tested, compared to the classical method where n is the number of independent reactions in the system. This has reduced the computation time for most complex reactions to a level, comparable to that needed for single reactions. The example used is the kinetic study of methanol synthesis in which the formation rates of methanol, methane, ethanol and ethane are considered. Two adequately accurate models were obtained from an extensive range of plausible models by using the new model discrimination and parameter estimation method with a relatively small computation effort.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110149
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  • 22
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    Evaporation and pervaporation of a binary mixture from an inert carrier liquidDedicated to Professor Hanns Hofmann on the occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 384-391 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bench-Scale experiments were carried out with the ternary mixture 2-propanol/water/glycerol. In a cylindrical vessel, the stirred and thermostated liquid was exposed to a preheated and either dry or humidified air stream. The mixture was evaporated either from a free surface or from the surface of a porous plate. On evaporating the mixture from a porous plate into a dry air stream, the less volatile component water escapes preferentially; in the case of evaporation from a free surface, water is retained in the mixture. In the former case, selectivity is liquid diffusion controlled, in the latter, the gas-side mass transfer and the thermodynamic equilibrium are the controlling mechanisms. On reducing the gas flow rate, the more volatile alcohol evaporates preferentially in both cases; the selectivity is controlled only by thermodynamic equilibrium. Humidification of the air stream with water vapour causes preferential evaporation of the alcohol at an increased rate. Furthermore, instabilities in the liquid boundary layer due to density gradients and surface tension effects may affect the selectivity of evaporation. Experimental results show that the selectivity of evaporation can be manipulated by choosing appropriate evaporation conditions. The theory, which applies the generalized Stefan-Maxwell equations to diffusion in the liquid, can describe these effects.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110150
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  • 23
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    Electronic Resource
    Remarks upon the modelling of heterogeneous catalytic reactors - the single fluid-solid casesDedicated to Professor Hanns Hofmann on the occasion of his 65the birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 425-431 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: To our benefit, the modelling of fluid-solid catalyzed reaction-reactor systems has long been the keen concern of Hanns Paul Hofmann. In the light of his instruction we remark upon key aspects of modelling for the (a) fixed bed (b) fluid bed and (c) moving bed/transport line reactors. There emerges from such analyses a properly renewed awareness of the need for a more sophisticated respect for reliable physical-chemical data. As Hanns has taught us, our models are no btter than our data.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110154
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  • 24
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    Two-phase flow in porous mediaThe Orginal, shorter form of this paper was presented by the author, as an invited speaker, at the Second Conferance of “Chemical Reaction Engineering” of the Engineering Foundation, March 8 to 13, 1987, Santa Barbara, California.Dedicated to Professor Dr. Hanns Hofmann on the ocassion of his 65th bithday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 407-424 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two-phase flow in porous media depends on many factors, such as displacement vs steady two-phase flow, saturation, wettability conditions, wetting fluid vs non-wetting fluid is displacing, the capillary number, interfacial tension, viscosity ratio, pressure gradient, uniformly wetted vs mixed-wet pore surface, uniform vs distributed pore throats, small vs large pores, well-connected pores vs pores connected by small throats, etc. These parameters determine how the two fluids are distributed in the pores, e.g. whether they flow in seperate channels or side-by-side in the same channels, either with both fluids being continous or only one fluid being continous and the other discontinuous. In displacement, the capillary number and the viscosity ratio determine whether the displacement front is sharp, or if there is either capillary or viscous fingering.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110153
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  • 25
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    Kinetic investigation of methacrylic acid synthesis on hetropoly-compoundsDedicated to Professor Dr. Hanns Hofmann on the ocassion of his 65th bithday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 392-402 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of heterogeneously catalyzed methacrylic acid synthesis from isobutyric acid has been investigated. Initial catalyst screening pointed to 10-molybdo-2-vanado-phosphoric acid and its Cs-salts as the most promising catalysts. A model describing the reaction behaviour of all the different hetropoly-compounds used in this work was developed. A relationship was found between model parameters and composition of different catalysts. First insight was gained into the catalyst deactivation phenomena. Deactivation appears to be caused mainly by loss of molybdenum with simultaneous collapse of the Keggin structure.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110151
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  • 26
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    A new regenerable process for the recovery of SO2Dedicated to Professor Hanns Hofmann on the occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 402-407 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Increasing demand for regenerable processes with SO2 recovery is to be expected. Advantages and limitations of the earlier developed citrate and adipate absorption/ steam stripping process are compared with those of the Wellman-Lord (sulphite) process. On the basis of comprehensive laboratory studies, a new process is proposed which supplements the citrate and adipate process. In this new process, the absorbent is a concentrated sodium phosphate buffer and the loaded buffer is regenerated by evaporation. The main buffer component is Na2HPO4, but NaH2PO4 is added in order to obtain a more complete stripping of SO2 during regeneration. The new process promises excellent absorption properties for SO2 with extremely low oxidation losses, regeneration with few incrustation problems and appreciable energy savings.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110152
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  • 27
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    Derivation, selection, evaluation and use of asymptotes (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 63-72 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Asymptotes are known to be useful, but their potential in interpreting and correlating chemical and physical behaviour is seldom exploited fully. The derivation and selection of asymptotes for particular as well as limiting cases is described. The evaluation of the range of validity and applicability, if any, of asymptotes is also considered. Asymptotes are shown to be uniquely useful in the identification of groupings of variables which minimize parameteric variations, as upper and lower bounds, as trial functions in the method of weighted residuals, and most especially as components of correlating equations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110110
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  • 28
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    A robust pole-placement self-tuning controller for chemical process control: Theoretical studies and simulation (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 57-62 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A single variable pole-placement self-tuning controller (PPSTC) is used to simulate examples typical of chemical processes; i.e., open-loop stable, unstable, and unstable non-minimum phase systems with unknown varying process dead time. The PPSTC is shown to be effective in each case. Set-point tracking and rejection of randomly occurring deterministic disturbances for all three types of processes are achieved. Simultaneous estimation of process parameters and process time delay is realized by using a recursive extended least squares method.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110109
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  • 29
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    The influence of stress and attrition on crystal size distributionPaper presented at the Annual Meeting of German Chemical Engineers 1986, September 17 to 19, in Strasbourg.Dedicated to Prof. Dr.-Ing. Rolf Lacmann on the occasion of his 60th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 40-49 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An important parameter influencing the crystal size distribution in mass crystallization from solution is the mechanical stress exerted on crystals in the crystallizer. This contribution presents the study of the influence of mechanical stress and attrition of the system potassium nitrate-water in an FC-crystallizer and in various draft-tube crystallizers, fitted with different types of impellers. The intensity of stress is a newly defined variable which is used to describe the level of stress in crystallizers. The reduction of crystal size by attrition is described by the linear attrition rate. The influence of impeller design and crystal hold-up on crystal size distribution and scale-up rules is discussed.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110107
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  • 30
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    Experimental results from a plate-column wet scrubber with gas-atomized sprayPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 73-79 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A pilot wet scrubber was examined experimentally. It is constructed like a plate column. Its plates are designed to set the gas into a whirling motion with tangential velocities of up to 25 m/s and to ensure a uniform distribution of the liquid throughout the gas flow. Particles suspended in the waste gas are collected by gas-atomized droplets to yield cut diameters between one and two microns. Energy consumption is lower than in the case of other scrubbers. The scrubbing mechanisms are analyzed by examining the measured pressure drops. Finally, methods of determining the collection efficiency are discussed and an empirical approach to its calculation is presented.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110111
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  • 31
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    Attrition and secondary nucleation in crystallizers (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 80-88 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mean crystal size of coarse crystalline products is determined by secondary nucleation and crystal growth. Secondary unclei are mainly produced by contacts of crystals with parts of the crystallizer or with other crystals. As a consequence, attrition effects are very important. In this paper, a model is proposed in order to calculate the attrition rate of crystals, depending on the physical properties of the crystalline product, the geometry of the crystallizer and on the operating conditions such as the stirrer speed or the suspension density. The effective rate of secondary nucleation can be expressed in terms of the attrition rate by introducing effective values for number and size of attrition particles. Finally, a scale-up criterion based on this model is derived. This criterion allows to predict effective rates of secondary nucleation and mean crystal sizes if data obtained in a laboratory crystallizer are available.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110112
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  • 32
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    Effect of combustion air preheating on NOx emissions from gas burners in high-temperature industrial applicationsPresented by M. Flamme at the “Jahrestreffen der verfahrens-ingenieure”, strasbourg, september 17 to 19, 1986. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 104-112 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: NOx emissions from different commercial gas burners for metal heat treatment applications were measured for a research project of the Gaswärme-Institut. The burners, rated at up to 50 kW, were installed for the tests in a laboratory combustion chamber operated at temperatures of up to 1400°C. The air for combustion was preheated to maximum temperature of 600°C. Following the tests, the potentials of different NOx control techniques were investigated. Methods explored included staged combustion air injection, staged fuel injection and fuel gas injection into the flue for NOx reduction. The results showed that it is feasible to reduce the NOx content of flue gases by as much as 90%.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110115
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  • 33
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    Theoretical and experimental study of sedimentation in vertical flow tanks (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 95-104 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Settling characteristics of four different suspensions were measured by batch settling tests (glass spheres in glycerol-water mixtures and CaCO3) and by continuous settling test in a bench-scale vertical flow tank (activated sludge and kaolin in water), including the measurement of solids concentrations inside the tank. The characteristics could be described by different correlation functions which now include all the information about the settling behaviour of ideal suspensions. Continuous settling experiments in a bench-scale vertical flow tank were carried out with the same four material systems. These results correspond with sufficient accuracy to those from the theory of limiting flux if the settling characteristics determined earlier are considered.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110114
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  • 34
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    Thermal deactivation of heterogeneous catalyst, part 1. The theta-rule - a critical review (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 113-119 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Thermal deactivation can be described either by deactivation kinetics or by the isokinetic effect. The latter expression is used synonymously with the “compensation effect” and the “Theta-Rule”. An examination of the original literature shows that only the compensation effect is applicable to thermal deactivation but not the Theta-Rule. The introduction of the preparation temperature as a parameter of the compensation effect results in a “modified Theta-Rule”, which describes the experimental data and is proposed for the non-separable kinetics. The consequence of the observed deviations from the validity range of the Theta-Rule is that the activation energy cannot be used as a universal activity criterion.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110116
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  • 35
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    The stability of crude oil residues and factors affecting their decomposition during mild thermal treatment (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 89-94 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A number of topped crude oil residues were subjected to mild thermal cracking in the temperature range between 613 and 673K at N2 pressure of one atmosphere. It was found that the thermal stability of the six topped crude oils decreased in the order Brent 〈 Piper 〈 Auk 〈 Saudi Arabian 〈 Romashkinskaya 〈 Tia Juana Pesado. This was measured in terms of light end production (C1-C5 hydrocarbons). The asphaltene, sulphur and metal (nickel and vanadium) contents were also determined. The production of light ends, exemplified by methane, was found to be related to the metal asphaltene content of the crude oils, but the sulphur content exerted a moderating influence upon the extent of cracking. Hence, metal asphaltenes, probably as metal porphyrins, catalyse cracking but the presence of sulphur reduces that catalytic activity and can inhibit cracking. If cracking of long chain hydrocarbons is to be minimized, metal asphaltenes should be removed (preferably) or reduced in concentration or poisoned, in order to decrease their catalytic activity.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110113
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  • 36
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    Kinetic analysis of the oxidation of isobutyraldehyde in liquid phase (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 120-126 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of non-catalytic as well as catalytic oxidation of Isobutyraldehyde has been investigated. Reaction rate equations for the formation of the main product isobutyric acid and of the side products acetone, CO and CO2 were derived. Kinetic parameters, namely the order of reaction, preexponential factor and activation energy were estimated by non-linear regression. The influence of selectivity and activity of the different type of catalysts employed was investigated quantitatively.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110117
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  • 37
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    Relationship between residence time, fluid dynamics and efficiency in countercurrent flow equipmentPaper presented at AIChE Annual Meeting 1986, Miami Beach, Florida, USA (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 139-148 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The suitability of any item of equipment for a given thermal separation process cannot always be judged solely in the light of efficient and loading range data. In vacuum rectification, involving a large number of theoretical stages, the vapour pressure drop per transfer unit exerts a considerable effect on the energy consumption and thus largely governs the choice of column fittings. Furthermore, the pressure drop per transfer unit determines the temperature at the bottom of a rectification column and, hence, the suitability of the equipment for the separation of heat-sensitive products. It is also an important criterion for compressor requirements in absorption processes. Another factor of considerable importance in separating heat-sensitive mixtures by distillation is the time during which the product, particularly the liquid phase, is exposed to a given temperature in the column. Therefore, a standardized liquid residence time has been adopted to evaluate the systems in their entirely. This residence time depends on the hydrodynamic conditions in the column and is thus closely related to pressure drop and efficiency. Further important factors, which may decide the selection of column internals, are the specific volume and mass of the column. Based on theoretical considerations, a flow model is derived for describing the main loading range of countercurrent packed columns; the relationships between the above mentioned parameters are presented.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110119
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  • 38
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    The significance of fly ash in wet-dry scrubbing of SO2 (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 298-305 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A bench scale flue gas desulphurization spray dry scrubbing unit was employed to study the effect of fly ash on the removal of SO2. The equipment consisted of a spray dryer with and ultrasonic nozzle for atomization and a pulse jet baghouse. The flue gas rate was 1500 lN/h (dry gas). Four fly ashes, originating from different countries were investigated. The alkalinity and reactivity of the fly ashes were determined in a pH-stat equipment. Pure fly ash removed SO2 in both the spray dryer and in the baghouse. An increase of humidity divided the fly ashes into two groups. The high calcium fly ash gave a considerably higher SO2 removal than the medium and low calcium fly ashes which showed similar SO2 removals. Fly ash did not enhance the removal of SO2 when added to a lime slurry because lime suppresses the dissolution of the alkali in the fly ashes. The pressure drop build-up in the fabric filter showed a strong dependence on material properties.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110139
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  • 39
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    Less known behaviour of gas-solid reactions: The expanding core model in catalytic and non-catalytic systemsDedicated to Profeesor Dr. Hanns Hofmann on the Occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 438-447 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Gas-solid reactions cover a wide spectrum of industrial products. Over the years, many conceptual models have been developed to describe the progress of a gas-solid reaction starting outside the solid particle as well as that occurring throughout the particle. But the behaviour of a reaction, initiated inside the pellet, is less known. In this paper, a brief outline is given of this relatively rare but important mode of gas-solid reaction. The causes of this relatively less known behaviour and characteristic features of five typical systems displaying it are discussed.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110156
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  • 40
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    A new appraisal of mass transfer processes in zeolites by transient methodsDedicated to Professor Dr. Hanns Hofmann on the occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 432-438 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Transient diffusion of inert gases into Zeolon 900 H, a zeolite of the mordenite type, was studied by the chromatographic method. Experiments were performed with argon and helium either as tracer or as carrier gas. The diffusion of argon was also studied in a carrier gas containing methanol at a low temperature (75°C, no reaction) and at higher temperatures (up to 130°C) when some dehydration of methanol to dimethyl ether takes place. The adsorption isotherm of argon is linear. In the absence of methanol, its penetration into microcrystals of zeolite is equally well represented either by an effective diffusion coefficient D′μ = 7.4 × 10-8exp(-2873/T)m2s-1 or by a mass transfer coefficient at the crystallite surface keμ = 1.9 × 10-4 exp(-1324/T) ms-1. A small amount of methanol in the carrier gas considerably slows down the transfer of argon (by a factor of 40 for D′μ and 550 for keμ) showing the “blocking” effect of adsorbed methanol. In addition, transient adsorption can no longer be accounted for by a single transfer time. The size distribution of microcrystals, determined from Scanning Electron Microscope photographs leads to a Transfer Time Distribution which account well for experimental breakthrough curves without any parameter fitting. This interpretation is supported by experiments under reaction conditions where transport of argon within crystallites increases faster with temperature than in the absence of reaction due to the transformation of methanol into dimethyl ether, which is less adsorbed and thus provides lesser hindrance to argon diffusion.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270110155
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  • 41
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    Interfacial areas and gas hold-ups at elevated pressures in a mechanically agitated gas-liquid reactor (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 1-10 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Interfacial areas and gas hold-ups were determined at pressures of up to 1.7 MPa in a glass vessel, 88 mm in diameter and of standard geometry. Superficial gas velocities between 0.25 and 2.0 cm/s were used and the stirring speed varied between 4 and 30 rps. The interfacial areas were determined by the chemical method, using the model reaction between CO2 and aqueous diethanolamine (DEA). Hold-ups were determined by observation of differences in height. In contrast to literature indications, the gas hold-up was found to be independent of reactor pressure. This is also true for the interfacial area.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110102
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  • 42
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    Effect of chlorine on the selectivity of a fischer-tropsch catalyst composed of iron/vanadium oxidesDedicated to Professor Dr. Karl Schügerl on the occasion of his sixtieth birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 32-39 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fischer-Tropsch catalysts (Fe/V oxides with ZnO and K2CO3 as promoters) were exposed to CHCl3, thereby producing surface and bulk chlorides. The effect of this exposure on activity and selectivity was studied in a continuous recycle reactor at a total pressure of 10 bar (CO/H2 in most experiments: ca 1:1) in a temperature range between 200 and 343°C. CHCl3 was introduced in amounts of up to 1 × 10-2 mol chlorine per g catalyst. The catalyst samples were characterized by internal surface area, pore-size distribution and adsorption capacities for CO, H2 and C2H4. Prior to synthesis, the catalysts were reduced by H2. Catalyst exposure to CHCl3 resulted in a decrease of activity and considerable changes in product distribution. Hydrogenation and isomerization of 1-olefins were partly suppressed; the chain length of the products was slightly increased. Deactivation of the catalysts due to chlorine addition was partly reversible during operation, while olefin formation was not significantly altered with time-on-stream. The effect of chlorine on activity and selectivity is explained by dissociation of CO as the chain initiating step and CO insertion into a carbon/metal bond as a possible chain propagation step. Since adsorption capacity for H2 decreases on the addition of chlorine, this may also contribute to lower activity and change in selectivity, compared to the unexposed catalyst.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110106
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    A new fluid dynamic model for mixing of newtonian and power-law liquids in the transient regimeModified version of a paper presented at the “GVC Working Party on Mixing”, Trier, 4./5. May 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 162-170 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the description of mixing processes influenced by viscosity in pseudoplastic (power-law) fluids, a definition of representative viscosity is normally used which takes into account the variable flow behaviour of the stirred material as a result of different shear stresses. In this context, the Metzner and Otto concept, which postulates that a representative shear rate is proportional to stirring speed, has become widely know, although the power calculation is inaccurate, particularly in the transient regime between the laminar and turbulent flow. A new model of fluid dynamics in the mixing vessel is presented, based on the increase of the mean flow velocity standardized with the stirrer's tip velocity in the transition regime. It provides a physical explanation for the above deviations. A suitable definition of representative viscosity substantially improves the accuracy of calculations of the stirring power in power-law fluids.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110122
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  • 44
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    Influence of mechanical stress on the growth of Rhizopus nigricans in stirred bioreactorsPaper presented at the “Jahrestreffen der Verfahrensigenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 178-187 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This investigation was undertaken in order to examine the factors affecting mechanical damage to micro-organisms in stirred bioreactors. Growth of the mould Rhizopus nigricans was studied in stirred bioreactors at different geometrical and operating parameters. Since experimental results cannot be described by conventional key parameters, a new concept has been suggested. It is based on the analogy to processes of mechanical disintegration. It is shown that the same key parameter, i.e. the ratio of power input to flow rate, can be used for a satisfactory correlation of experimental data on mechanical damage to micro-organisms, which is an important step in the recovery of intracellular products in biotechnology.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110124
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  • 45
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    Thermal deactivation of heterogeneous catalysts. Part 2: The compensation effect and the Catalytic Paradox (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 228-236 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The interpretation of the term “compensation” obscures a logical contradiction, the catalytic paradox, which is caused by inconsistent validity ranges of the Arrhenius parameters, the pre-exponential factor and the activation energy. For this reason, a theory which contains the Arrhenius parameters cannot be established for the entire system (whole temperature range) on the basis of classical logic. Only the subsystems can be consistent and complete. One subsystem is the range of the topocatalytic concept which is relevant for thermal deactivation, thermal bistability and for all reactions with surface dependence of activity. The other is the range of the energetic concept which is preferred in fundamental research. In order to complete the subsystems, new consistent symbols are introduced. The change of particle size caused by thermal deactivation can result in four possible particle size effects, two of which have been discussed in the literature.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110130
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  • 46
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    Thermal radiation of gas/solid mixturesPaper presented by Th. Elsner at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 237-243 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Thermal radiation of gas/solid mixtures in high-temperature heat exchangers is of considerable importance for the design of heat exchange surfaces. Therefore, an experimental plant was constructed to measure solid particle emissivities, since there is a lack of relevant data in the existing literature. A theoretical equation was derived to describe the solid particle emissivity as a function of layer thickness, specific solid surface area, solid loading and absorption and scatter coefficients. Measurements were carried out for fluidized bed ash and quartz sand. The emissivities of these particle fractions increase with increasing layer thickness, slid loading, specific solid surface area and temperature. The description of these data by the derived model equation is very satisfactory. No dependence on wavelength was observed. The ash components do exert some influence which, for the present, cannot be described exactly.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110131
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  • 47
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    Application of modern packings in thermal separation processesPaper presented by R. Villet at ACHEMA ′85. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 213-227 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A report is presented on the performance of modern dumped and structured packings for application in the field of thermal separation processes. The evaluation of the results is based on extensive experimental investigations of rectification, absorption, and desorption systems. The following are indicated: the efficiency in terms of the number of theoretical stages per unit height or in terms of the height of transfer unit or volumetric mass transfer coefficient, the pressure drop per unit height as well as per theoretical stage or per gas phase transfer unit, and the liquid hold-up, whereby either the gas capacity factor or the liquid load was adopted as influencing parameter, and finally the maximum gas capacity factor as a function of the flow parameter. The results are presented in diagrams and tables.
    Additional Material: 25 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110129
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  • 48
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    Volumetric mass transfer coefficient in stirred reactors (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 249-251 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It is shown that the volumetric mass transfer coefficients, presented recently by Schmitz et al. [1] for viscous solutions of carboxymethyl cellulose (CMC) in aqueous sodium sulphite, are considerably underestimated as a result of unjustified neglect of the oxygen back pressure during oxygen absorption. Schmitz et. al. [1] found a decrease in the exponent n in the relationship between the oxygen mass transfer coefficient, kla, and the power dissipated per unit volume of the liquid phase, e (kla ∝ en), and ascribed it to viscosity effects. However, no such decrease is observed, provided that the actual oxygen back pressure is taken into account.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110133
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  • 49
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    Mass transfer in centrifugal extractorsPaper presented by F. Otillinger at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 312-320 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This contribution presents the methods of measuring the mass transfer in centrifugal extractors and of determining it during the individual life stages of a fluid element of the dispersed liquid, i.e. drop formation, motion, coalescence and stay in the stationary layer of the dispersed phase. The experimental mass transfer coefficients of the dispersed and continuous phases are compared with well-known theoretical models developed for extraction columns in gravitational field. Due to the fast motion and coalescence of the fluid particles at high centrifugal field intensities, mass transfer in centrifugal extractors takes place during short contact times. Nevertheless, this contribution shows that mass transfer in a centrifugal field can be calculated with selected theoretical models of the gravitational field. The investigations on mass transfer are completed by a classification of the strongly deformed fluid particles in centrifugal field into regimes of circulating and oscillating drops. In addition, data on the performance of centrifugal extractors, undergoing several exchange steps, are given.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110141
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  • 50
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    Effect of enzyme inhibition on the performance of packed-bed biological reactor - a theoretical study (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 50-56 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The performance characteristic of a packed bed reactor has been analyzed by considering diffusional resistance of the biofilm. Model equations were solved by the method of orthogonal collocation for various classical enzyme inhibition kinetics, including partially non-competitive, partially competitive, partially uncompetitive, partially mixed and fully mixed. For all considered modes of inhibition, an increase in the inlet substrate concentration decreases the steady state conversion in the reactor. However, an increase in the Peclet number has been found to improve the conversion. The effects of various other process variables of physical importance were also investigated parametrically.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110108
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  • 51
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    Absorption of SO2 by aqueous NaOH solutions in the presence of a surfactant (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 156-162 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A report is presented on the influence of liquid flow rate, NaOH concentration, column length and presence of 5 × 10-3 wt-% of the surfactant SLS on the rate of absorption of pure SO2 by aqueous NaOH solution in a sphere-and-cylinder column. The presence of sodium lauryl sulphate (SLS) prevented axial turbulence which increased mass transfer in longer columns and was almost independent of the flow rate. The enhancement factor due to the reaction between SO2 and NaOH with respect to the process of physical absorption was analyzed for the systems with excess OH- in the outflow. The results obtained in the presence of a surfactant are satisfactorily explained by film theory with a single reaction plane model. Those obtained in the absence of surfactant are best described by a two-plane model using renewal theory.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110121
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  • 52
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    Measurement of temperature fields in mixing vessels using optical topographyPaper presented by W. Ostendorf at the “Jahrsterffen der Verfahrens- Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 148-155 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experimental investigation of stirring processes require the measurement of temperature changes and concentration profiles in all the zones of the mixing volume. The conversion of simultaneous chemical reactions during the mixing process depends on the local temperature and concentration. The time-dependent temperature and concentration fields can be recorded for the entire mixing volume with the use of optical tomography and correlated with time. This technique offers the possibility of continuous measurement of temperature and concentration changes during the mixing process throughout the measurement volume. In the described investigations, optical tomography is used to examine the transport and equalization processes during mixing in stirred vessels.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110120
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  • 53
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    Effect of ethane addition on propane pyrolysis (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 243-248 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pyrolysis of propane/argon mixture in the presence of trace quantities (0.1% and 0.9%) of ethane was investigated at reflected shock wave temperatures between 1200 and 2000K. Traces of ethane accelerated propane decomposition at high temperature. However, increase in the quantity of ethane added to propane/argon mixture did not result in the same increase of its accelerating influence. Ethylene, methane and acetylene were the main hydrocarbon reaction products, with small quantities of propylene and ethane detected only at lower temperatures. Below 1500K, addition of ethane slightly enhanced the yields of ethylene and methane at the expense of propylene and ethane respectively. The selectivity for acetylene increased with increasing temperature and with the decline of those for the other products. For none of the products, did the presence of ethane alter the relationship between product formation rates and temperature. The influence of ethane addition on propane pyrolysis at high temperatures was explained in terms of increased radical concentrations, especially hydrogen atoms and vinyl radicals, formed at high conversions. These accounted for the rapid acceleration of propane decomposition and the high yield of acetylene at high temperatures.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110132
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  • 54
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    Parametric sensitivity of the ignition process to mass transfer in adiabatic tubular reactors with exothermic heterogeneous reactions (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 251-258 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The alternative effects of reaction kinetics, mass, heat and momentum transport on mass conversion by chemical reactions are examined theoretically for a reacot tube with laminar flow. The reaction enthalpy is considered. A heterogeneous reaction between several gaseous components takes place at the inner surface of this reactor tube. Strongly exothermic reactions lead to self-acceleration of the reaction, unless reaction enthalpy is removed through the tube wall. Under certain conditions, there will be a sudden change from mass transfer controlled by the reaction to that controlled by diffusion. This phenomenon is known as ignition of the reaction. The effect of ignition and its sensitivity to reaction enthalpy, thermal conductivity and diffusivity of the fluid as well as activation energy of the first order heterogeneous wall reaction are investigated by a numerical solution of the transport equations. Axial conduction of heat and mass is neglected both in the fluid and in the tube wall. Non-stoichiometric wall reactions of first order, with temperature dependent reaction rates and equilibrium constants, are considered. The results are presented in graphical form, as plots of the local mass flux at the reacting wall as functions of the dimensionless tube length.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110134
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    Chemical engineering aspects of precipitation from solutionPaper presented by A. Mersmann at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, Spetember 30 to october 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 264-276 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Precipitation is a rapid solidification. As a rule, it applies to substances which are sparingly soluble and is coupled with a chemical reaction or with a salting out process. The chemical engineer has to ensure that the product obtained has a constant and preferably coarse size distribution. This contribution compares the literature data on crystallization of soluble and sparingly soluble substances; it can be shown that, during precipitation processes, nuclei are formed, most probably by a primary mechanism. Analysis of the processes occurring during precipitation, such as chemical reaction, mixing and crystallization, leads to recommendations for the operation of precipitation processes.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110136
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    Scale-up of mechanically agitated extraction columnsPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987 (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 259-263 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The deterioration of mass transfer efficiency of an extraction column with increasing column diameter is the result of developing residence time distributions. These effects can be described by one-dimensional dispersion model. However, it must be verified whether the requirements for its application are fulfilled in the different types of agitated extraction columns. For the columns for which the dispersion model can be applied, a relationship will be derived between the necessary increase of column height with column diameter. This is based on the equations for calculation of the dispersion coefficient of the continuous phase. If the dispersion model cannot be applied to given a type of column, an investigation will be made on the possible modifications of operation or changes in construction, in order to permit a scale-up procedures as proposed here.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110135
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  • 57
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    Zur Kenntnis von Alkalimetaselenoarseniten Darstellung und Kristallstrukturen von MAsSe2, M = K, Rb, Cs (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 561 (1988), S. 139-148 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Concerning Alkali Metal Metaselenoarsenites. Preparation and Crystal structures of MAsSe2, M = K, Rb, CsThe metaselenoarsenites MAsSe2, M = K, Rb, Cs were prepared by methanolothermal reaction of M2CO3 with As2Se3 at a temperature of 130°C. Their X-ray structural analyses demonstrated that the compounds contain polymetaselenoarsenite anions [AsSe2-]∞, in which the basic units are ψ-AsSe3 tetrahedra, which are linked via shared corners into infinite chains. Vierer single chains are observed for KAsSe2 and RbAsSe2, zweier single chains for CsAsSe2. The stretching units s are respectively 3,157, 2.336 and 3,378 Å. The relationship between the conformation of metaselenoarsenite chains and cation size is discussed.
    Notes: Die Metaselenoarsenite MAsSe2, M = K, Rb, Cs wurden durch methanolothermale Reaktion von M2CO3 mit As2Se3 bei einer Temperatur von 130°C dargestellt. Ihre Röntgenstrukturanalysen ergaben, daß die Verbindungen Polymetaselenoarsenit-Anionen [AsSe2-]∞ beinhalten, in denen die Grundelemente ψ-AsSe3-Tetraeder sind, die über gemeinsame Ecken zu unendlichen Ketten verknüpft sind. Für KAsSe2 und RbAsSe2 werden Vierer-, für CsAsSe2 Zweier-Einfachketten gefunden. Die Streckungseinheiten s betragen 3,157, 2,336 bzw. 3,378 Å. Die Beziehung zwischen Konformation von Metaselenoarsenitketten und Kationgröße wird erläutert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19885610115
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    Study on A4BX6 Compounds. II [1]. Refinement of the Structure of Rb4PbBr6 and a Note on the Existence of “Rb4Hgl6” and “K4CdI6” (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 562 (1988), S. 102-104 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Untersuchungen an A4BX6-Verbindungen. II. Strukturverfeinerung von Rb4PbBr6 und eine Bemerkung zur Existenz von „Rb4HgI6“ und „K4CdI6“Rb4PbBr6 wurde in einer Festkörperreaktion aus den binären Komponenten präpariert und die Struktur mit Einkristalldaten verfeinert (a = 1332,9(4), c = 1647,8(5) pm, R.Gr. R3c; K4CdCl6-Typ). Rb4HgI6 und K4CdI6 ließen sich nicht darstellen. Diese Ergebnisse werden im Zusammenhang mit dem Strukturfelddiagramm für A4BX6 Verbindungen diskutiert.
    Notes: Rb4PbBr6 was prepared by solid state reaction of the binary compounds and the structure refined with single crystal data (a = 1332.9(4), c = 1647.8(5) pm; space group R3c; K4CdCl6-type arrangement). Attempts to synthesize Rb4HgI6 and K4CdI6 were unsuccessful. The results are discussed on the basis of a structure field diagram for A4BX6 compounds.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19885620112
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  • 59
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    Die Kristallstruktur von Pb5(GeO4)2SO4 und Pb5(GeO4)2CrO4, zweier Bleiapatite mit unbesetzten Halogenlagen (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 562 (1988), S. 131-140 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Structures of Pb5(GeO4)2SO4 and Pb5(GeO4)2CrO4, Two Lead Apatites with Vacant Halogen SitesPb5(GeO4)2SO4 (a = 1005.8; c = 741.6 pm) and Pb5(GeO4)2CrO4 (a = 1010.5; c = 742.8 pm) are hexagonal, space group P63/m, Z = 2 formula units. They crystallize with the apatite structure type. The halogen positions in the channels are not occupied. This pecularity is caused by the Pb2+ ions on the 6h positions. Their lone pairs of electrons are sterically active, being directed into the channels. The electron lone pairs of the Pb2+ ions of the 4f positions also show sterical effect.
    Notes: Pb5(GeO4)2SO4 (a = 1005,8; c = 741,6 pm) und Pb5(GeO4)2CrO4 (a = 1010,5; c = 742,8 pm) sind hexagonal, Raumgruppe P63/m, Z = 2 Formeleinheiten. Sie kristallisierten in der Apatitstruktur, wobei die Halogenlagen in den Kanälen nicht besetzt werden. Diese Besonderheit ist durch die Pb2+-Ionen auf der Lage 6h bedingt. Ihre freien Elektronenpaare sind stereochemisch wirksam und weisen in die Kanäle hinein. Auch bei den Pb2+-Ionen auf der Lage 4f ist ein stereochemischer Einfluß des freien Elektronenpaares erkennbar.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19885620116
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    Study on A4BX6 Compounds. III [1]. ns2 cations as a prerequisite for a structure type and their interaction in ternary halides with the formula type A4BX6 (A: In, TI; B: Cd, Pb, Ge; X: Cl, Br, I) (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 562 (1988), S. 105-114 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Untersuchungen an A4BX6-Verbindungen. III. ns2-Kationen als Bedingung für einen Strukturtyp und ihre Wechselwirkung in ternären Halogeniden vom Typ A4BX6 (A: In, Tl; B: Cd, Pb, Ge; X: Cl, Br, I)Wir diskutieren die Art der Wechselwirkung von Kationen mit ns2-Konfiguration in ternären Halogeniden des Formeltypes A4BX6 (A: In, Tl; B: Cd, Pb, Ge; X: Cl, Br, I), die im Tl4HgBr6-Typ kristallisieren. Wir berichten über Hochdruckexperimente 'an solchen A4BX6-Verbindungen und über röntgenographische Untersuchungen und Kristallstrukturverfeinerungen an Mischkristallen des Typs A′xA4-xBX6, in denen die ns2-Kationen teilweise durch solche mit Edelgaskonfiguration substituiert sind. Die Ergebnisse unserer Experimente zeigen, daß die ns2-Kationen diesen ungewöhnlichen Strukturtyp durch Polarisationseffekte stabilisieren und durch ihre größere Elektronegativität im Vergleich zu der von Alkaliionen von ähnlicher Größe.
    Notes: We discuss the interaction of ns2-type cations in ternary halides of the formula type A4BX6 (A: In, Tl; B: Cd, Pb, Ge; X: Cl, Br, I) crystallizing in a Tl4HgBr6-type arrangement. We report on high pressure experiments on such A4BX6 compounds and on x-ray studies and structure refinements of mixed crystals of the type A′xA4-xBX6, where cations A′ with a closed shell configuration partly substitute for the ns2-type A ions. The results of our experiments show, that ns2-type cations stabilize this unusual structure type by polarization effects and by their higher electronegativity as compared with alkali ions of comparable size.
    Additional Material: 3 Ill.
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    Ag2PdCl4, Kristallstruktur und die kristallchemische Beziehung zum NaCl-Typ (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 562 (1988), S. 123-130 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ag2PdCl4, Crystal Structure and the Crystal Chemical Relation to the NaCl TypeAg2PdCl4 single crystals show orthorhombic symmetry with the space group Cmca (No. 64) and the lattice parameters a = 10.088(2), b = 8.051(5), c = 8.078(2) å, with 4 formular units per unit cell. The atomic arrangement of Ag2PdCl4 is explored by X-ray crystal structure analysis.Silver shows a distorted octahedral arrangement of chlorine atoms. Palladium forms typical, approximately square-planar PdCl4 groups. Ag2PdCl4 is a new variant of a partially occupied sodium chloride structure type.
    Notes: Die Kristallstruktur von Ag2PdCl4 wurde mit röntgenographischen Methoden an Einkristallen ermittelt. Ag2PdCl4 kristallisiert mit orthorhombischer Symmetrie: Cmca (No. 64), a = 10,088(2), b = 8,051(5), c = 8,078(2) å mit 4 Formeleinheiten pro Elementarzelle.Silber besitzt eine verzerrt oktaedrische Chlor-Nachbarschaft, während das Palladium annähernd quadratisch planare PdCl4-Gruppen bildet. Ag2PdCl4 stellt eine neue Variante einer teilbesetzten Natriumchloridstruktur dar.
    Additional Material: 6 Ill.
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    Zum Einfluß der Halogenmodifizierung auf das acide Verhalten von γ-Al2O3 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 562 (1988), S. 145-152 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Influence of Modification of γ-Alumina by Halides on the Acidic BehaviourThe influence of modification of γ-alumina by Cl and F on the acidic properties was studied by means of i.r. spectroscopic methods using ammonia as probe molecule. The measurements show a significant rise in Lewis acidity.
    Notes: Mittels IR-spektroskopischer Methoden wurde der Einfluß der Halogen-modifizierung auf das acide Verhalten von γ-Al2O3 im Hinblick auf dessen Verwendung als Träger in Reformingkatalysatoren untersucht. Als Sondenmolekül diente NH3. Die Messungen wiesen eine deutliche Verstärkung der Lewis-aciden Eigenschaften des modifizierten Al2O3 aus.
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    URL: http://dx.doi.org/10.1002/zaac.19885620118
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    27Al N.M.R. Studies on the Liquid Phases during Zeolite Synthesis (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 562 (1988), S. 141-144 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 27Al-NMR-Untersuchungen der flüssigen Phasen während der Zeolithsynthese27Al-NMR-Untersuchungen der während der Synthese der Zeolithe A, X und Y vorliegenden flüssigen Phasen zeigen, daß der molekulare Aufbau und die Menge der in den wäßrigen Lösungen vorliegenden Alumosilicationen für den entstehenden Zeolithtyp charakteristisch ist. Die Zahl der gebildeten Si—O—Al-Bindungen und ihre Mannigfaltigkeit steigt mit steigendem SiO2-Gehalt der Lösungen. Diese Ergebnisse stützen die Vorstellung, daß die Synthese von Zeolithen unter Ausbildung definierter Alumosilicate über die Lösungsphase abläuft.
    Notes: 27Al n.m.r. spectroscopy of liquid phases obtained during zeolite A, X, and Y synthesis reveals that the amount and the type of the present soluble aluminosilicate anions is characteristic for the different zeolite type; the number of the formed Si—O—Al bonds and their variety increases with increasing content of SiO2. The results support the suggestion about the formation mechanism of zeolites via distinct aluminosilicate “precursors” in solution.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19885620117
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    Über Chalkogenolate. 186 [1]. Untersuchungen über Salze der Pyruvinsäure 1. Darstellung und Charakterisierung von Pyruvaten (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 562 (1988), S. 160-164 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Chalcogenolates. 186. Studies on Salts of Pyruvic Acid. 1. Synthesis and Characterization of PyruvatesThe title compounds M[O2C—CO—CH3], where M = Na, K, NH4, Li = H2, Have been synthesized by neutralisation of pyruvic acid under different conditions.The pyruvates were characterized by means of electron absorption, infrared, nuclear magnetic resonance, and mass spectra.
    Notes: Die Titelverbindungen M[O2C—CO—CH3] mit M = Na, K, NH4, Li · H2O wurden durch Neutralisation der Pyruvinsäure unter verschiedenen Bedingungen synthetisiert.Die Charakterisierung der Pyruvate erfolgte mit Hilfe von Elektronenabsorptions-, Infrarot-, Kernresonanz- und Massenspektren.
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    Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. 52 [1]. Reaktion von Trialkoxysilanthiolen mit Carbonsäuren. Darstellung und Hydrolyse der Trialkoxyacyloxysilane (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 562 (1988), S. 153-159 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Silicon-Sulphur Compounds. 52. Reaction of Trialkoxysilanethiols with Carboxylic Acids. Preparation and Hydrolysis of TrialkoxyacyloxysilanesThe series of trialkoxyacyloxysilanes have been prepared almost quantitatively from trialkoxysilanethiols (RO)3SiSH (R = i-Pr, s-Bu, s-n-Am, s-i-Am) by the reaction with carboxylic acids R′COOH (R′ = Alkyl or Ph). Kinetics of the acidolysis of (RO)3SiSH as well as hydrolysis of (RO)3SiOCOR′ were investigated and consequently the reaction mechanisms are proposed.
    Notes: Durch Umsetzung von Trialkoxysilanthiolen (RO)3SiSH (R = i-Pr, s-Bu, s-n-Am, s-i-Am) und Carbonsäuren R′COOH (R′ = Alkyl bzw. Ph) wurden fast quantitativ mehrere Trialkoxyacyloxysilane (RO)3SiOCOR′ erhalten. Die Kinetik dieser Acidolysereaktion von (RO)3SiSH wie auch der Hydrolysereaktion von (RO)3SiOCOR′ wurde untersucht und in der Folge die Reaktionsmechanismen formuliert.
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    Zur Kenntnis von Na6Cu2O6 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 79-86 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Knowledge of Na6Cu2O6For the first time black single crystals of Na6Cu2O6 are obtained with a = 1094.8(1), b = 1203.6(1), c = 1638.1(2) pm, space group Cmca, Z = 12. Cu3+ is coordinated by four O2-. CuO4 groups are bound to planar, isolated Cu2O66- anions. Cu—O bond distances are between 181.6(3) and 186.4(4) pm and O—Cu—O bond angels in the range 84.0(1)° and 93.7(1)°. Effective Coordination Numbers, ECoN, Mean Fictive Ionic Radii, MEFIR, and the Madelung Part of Lattice Energy, MAPLE, are calculated.
    Notes: Erstmals wurden schwarze Einkristalle von Na6Cu2O6 mit a = 1094,8(1), b = 1203,6(1), c = 1638,1(2) pm, R. Gr. Cmca, Z = 12 dargestellt. Cu3+ ist planar von vier O2-umgeben. Je zwei CuO4-Gruppen sind zu planaren, isolierten Anionen Cu2O66- verknüpft. Die Abstände Cu—O liegen zwischen 181,6(3) und 186,4(4) pm, die Winkel O—Cu—O zwischen 84,0(1)° und 93,7(1)°. Die Effektiven Koordinationszahlen, ECoN, Mittleren Fiktiven Ionenradien, MEFIR, und der Madelunganteil der Gitterenergie, MAPLE, wurden berechnet.
    Additional Material: 2 Ill.
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    Synthese, IR- und EPR-Spektren sowie die Kristallstruktur von HPPh3[WOCl4(OPPh3)] (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 70-78 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, I.R. and E.P.R. Spectra, and Crystal Structure of HPPh3[WOCl4(OPPh3)]Partial hydrolysis of the alkyne complex [WCl4(PhC≡CPh)]2 in the presence of triphenylphosphine and dichloromethane as oxidizing agent and solvent yields dark green crystals of the complex HPPh3[WOCl4(OPPh3)]. Attempts to prepare the compound directly by the reaction of WOCl3 with PPh3, OPPh3 and HCl in dichloromethane were unsuccessful.HPPh3[WOCl4(OPPh3)] was characterized by its i.r. and e.p.r. spectrum. As shown by a crystals structure determination (1835 independent, observed reflections, R = 0.056) the complex crystallizes monoclinically in the space group P21/n with four formula units per unit cell. The complex consists of HPPh3+ and [WOCl4(OPPh3)]- ions, in which the tungsten atom is in a distorted octahedral environment, surrounded by four equatorial chlorine atoms, by one axial oxygen atom (bond length WO = 172 pm), and by the oxygen atom of the OPPh3 molecule (WO = 206 pm).
    Notes: HPPh3[WOCl4(OPPh3)] entsteht in Form dunkelgrüner Kristalle bei der partiellen Hydrolyse des Diphenylacetylenkomplexes [WCl4(PhC≡CPh)]2 bei Anwesenheit von Triphenylphosphan und Dichlormethan als Oxidations- und Lösungsmittel. Versuche, die Verbindung aus WOCl3, PPh3, OPPh3 und HCl in Dichlormethan direkt herzustellen, mißlangen.HPPh3[WOCl4(OPPh3)] haben wir durch das IR- und das EPR-Spektrum charakterisiert. Nach der röntgenographischen Strukturanalyse (1835 unabhängige, beobachtete, beobachtete Reflexe, R = 5,6%) kristallisiert die Verbindung monoklin in der Raumgruppe P21/n mit vier Formeleinheiten pro Elementarzelle. Sie ist aus HPPh3+-Ionen und Anionen [WOCl4(OPPh3)]- aufgebaut, in denen das Wolframatom verzerrt oktaedrisch von vier äquatorial angeordneten Chloratomen und axial von einem terminalen O-Atom (Bindungsabstand WO = 172 pm) und von dem O-Atom des OPPh3-Moleküls (WO = 206 pm) umgeben ist.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19885630111
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    Komplexbildung mit sulfonamidsubstituierten Thionoliganden (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 105-115 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complex Formation by Sulfonamide Substituted ThionoligandsThionoligands containing arenesulfonamido or arenesulfonylhydrazido functions as a second donor group (STAT-, PST-, BPTS- and TPTH-, meaning of the abbreviations see text) form 1,2 complexes with nickel(II), cobalt(II), and zinc(II). The six-membered chelates M(STAT)2 (M = Co, Ni) are high-spin (\documentclass{article}\pagestyle{empty}\begin{document}$ \rm{S} \mathop {\rm N}\limits^ \ominus $\end{document} coordination). On the other hand no coordination of the RSO2N group is observed in the complexes M(PST)2 (M = Co, Mn, Fe), but the formation of a four membered ring including one nitrogen atom of the heterocycle. This statement is primarily based on a comparison with complexes of teh structurally related ligands PPT- and CPT- containing no \documentclass{article}\pagestyle{empty}\begin{document}$ \rm{RSO}_2 \mathop {\rm N}\limits^ \ominus $\end{document} groups. Evidently in the chelat Co(BPTS)2 the anionic RSO2N group is a weak bidentate donor.
    Notes: Thionoliganden, die Arensulfonylamido- bzw. Arensulfonylhydrazidofunktionen als zweite Donatorgruppen enthalten (STAT-, PST-, BPTS- und TPTH-, zur Bedeutung der Abkürzungen vgl. Text), bilden mit Nickel(II), Cobalt(II) und Zink(II) 1,2-Komplexe. Die Sechsringchelate M(STAT)2 (M = Co, Ni) gehören zum High-spin-Typ (\documentclass{article}\pagestyle{empty}\begin{document}$ \rm{S} \mathop {\rm N}\limits^ \ominus $\end{document})-Koordination. Dagegen erfolgt in den Komplexen M(PST)2 (M = Co, Mn, Fe) keine Koordination über die \documentclass{article}\pagestyle{empty}\begin{document}$ \rm{RSO}_2 \mathop {\rm N}\limits^ \ominus $\end{document} Funktionen sondern über ein Stickstoffatom des Pyrimidinrings (Bildung eines Chelatvierringes). Diese Aussage wird durch einen Vergleich mit Komplexen der strukturell verwandten Liganden PPT- und CPT- gestützt, die keine RSO2N-Gruppen enthalten. In dem Chelat Co(BPTS)2 koordiniert RSO2N- offenbar als zweizähliger anionischer Ligand mit schwacher Donatorwirkung. Die Charakterisierung der neuen Chelate erfolgt anhand der magnetischen Momente, der UV/VIS- und der ESCA-Spektren. Die vorliegenden und früheren Ergebnisse ermöglichen Aussagen über die Variabilität des RSO2N-Liganden: Normalerweise erfolgt die Koordination über den N-Ligator. Es ist aber auch eine Bindung über ein Sauerstoffatom, wenn dadurch ein stabiler Chelatsechsring gebildet werden kann, oder als zweizähliger anionischer Ligand geringer Donatorstärke möglich. Die art der Koordination des RSO2N-Liganden hängt vom Zentralatom ab. Bisher konnten keine Komplexe mit einer direkten koordinativen Bindung von \documentclass{article}\pagestyle{empty}\begin{document}$ \rm{RSO}_2 \mathop {\rm N}\limits^ \ominus $\end{document} an Eisen(II) oder Mangan (II) nachgewiesen werden.
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    Synthese und Strukturuntersuchungen von Iodocupraten(I). IX. Synthese und Kristallstrukturen von Cs3Cu2I5 und RbCu2I3 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 96-104 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Structure Analyses of Iodocuprates (I). IX. Syntheses and Crystal Structures of Cs3Cu2I5 and RbCu2I3Cs3Cu2I5 and Rb∞1[Cu2I3] were prepared by the reaction of CsI or RbI with CuI in solution (acetonitrile or acetone) or by solid state reaction. The crystal structure analysis of Cs3Cu2I5 (orthorhombic, Pbnm, a = 1438.6(6), b = 1014.7(5), c = 1167.5(5) pm, Z = 4) shows, that the compound contains dinuclear anions Cu2I53- in which the I atoms are arranged to trigonal bipyramids; one CuI occupies one of the two I tetrahedral holes, the other a trigonal site of the neighbouring tetrahedron. Rb∞1[Cu2I3] (orthorhombic, Cmcm, a = 1070.6(7), b = 1338.3(8), c = 572.8(3) pm, Z = 4) is built up by CuI4 double chains; the compound is isomorphic with Cs∞1[Cu2I3].
    Notes: Cs3Cu2I5 und Rb∞1[Cu2I3] werden durch Umsetzung von CsI bzw. RbI mit CuI in Lösung (Acetonitril bzw. Aceton) oder durch Festkörperreaktion hergestellt. Die Kristallstrukturanalyse von Cs3Cu2I5 (orthorhombisch, Pbnm, a = 1438,6(6), b = 1014,7(5), c = 1167,5(5) pm, Z = 4) ergab, daß diese Verbindung zweikernige Anionen Cu2I53- enthält. Die Iodatome bilden eine trigonale Bipyramide mit einem CuI in einer der beiden Tetraederlücken. Das zweite CuI besetzt eine Dreiecksfläche des anderen Tetraeders. Im Rb∞1[Cu2I3] (orthorhombisch, Cmcm, a = 1070,6(7), b = 1338,3(8), c = 572,8(3) pm, Z = 4) liegen CuI4-Tetraederdoppelketten vor; die Verbindung ist isomorph mit CsCu2I3.
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    Über Chalkogenolate. 187. Untersuchungen über Salze der Pyruvinsäure 2. Kristallstruktur von Kaliumpyruvat, Neubestimmung der Struktur von Natriumpyruvat (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 87-95 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Chalcogenolates. 187. Studies on Salts of the Pyruvic Acid. 2. Crystal Structure of Potassium Pyruvate, Redetermination of the Structure of Sodium PyruvateThe title compounds M[O2C—CO—CH3], where M = Na and K, crystallize with Z = 4 in the monoclinic space group P21/n; cell dimensions see “Inhaltsübersicht”.The structure of the Na+ and K+ salt resp. has been determined from single crystal X-ray data measured at 20°C and refined to R's of 0.051 and 0.055 resp. (Rw = 0.055 and 0.057 resp.) for 1065 and 1308 resp. independent reflections.Both compounds are isostructural. The alkali metal ions are surrounded by seven oxygen atoms from five anions forming an irregular polyhedron.
    Notes: Die Titelverbindungen M[O2C—CO—;CH3] mit M = Na, K kristallisieren monoklin mit Z = 4 in der Raumgruppe P21/n; Na[O2C—CO—CH3] a = 21, 905(3) Å, K[O2C—CO—CH3] a = 22,027(2) Å, b = 5,269(1) Å, b = 5,835(2) Å, c = 3,671(1) Å, c = 4,004(4) Å, β = 91,34(2)°. β = 90,88(3)°. Für die Na+-bzw. K+-Verbindung wurde die Struktur aus bei 20°C vermessenen röntgenographischen Einkristalldaten unter Verwendung von 1065 bzw. 1308 symmetrieunabhängigen Reflexen bestimmt und bis auf Gütefaktoren von R = 0,051 bzw. 0,055 und Rw = 0,055 bzw. 0,057 verfeinert.Beide Verbindungen sind isostrukturell. Das jeweilige Alkalimetallion ist von sieben O-Atomen, die von fünf verschiedenen Anionen stammen, unregelmäßig koordiniert.
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    Untersuchungen an oxidischen Katalysatoren. XLV. Umwandlung von Aromaten an dealuminierten ZSM-5-Zeolithen (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 127-135 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Oxide Catalysts. XLV. Conversion of Aromatics on Dealuminated Zeolites ZSM-5The catalytic properties of zeolites ZSM-5 dealuminated by hydrochloric acid are investigated in the isomerization of m-Xylene, the disproportionation of toluene and in the alkylation of toluene with methanol. Besides the increase of the Si/Al ratio, the dealumination leads to an inversion of the Si/Al concentration gradient in crystallites, to a shift of acidity spectrum and consequently to a change in catalytic activity and selectivity.
    Notes: An säuredealuminierten HZSM-5-Proben werden die m-Xylen-Isomerisierung, die Toluendisproportionierung und die Toluenalkylierung mit Methanol untersucht. Die Säuredealuminierung bewirkt neben der Moduländerung eine Umkehr des Si/Al-Konzentrationsgradienten in den Zeolithkristalliten, eine Verschiebung des Aciditätsspektrums und damit eine Veränderung von Aktivität und Selektivität in den katalytischen Reaktionen.
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    URL: http://dx.doi.org/10.1002/zaac.19885630117
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    Imidodiphosphorsäuretetraphenylester als Ligand in Fluorokomplexen. 1. Fluorokomplexe des Titans (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 167-172 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Tetraphenyl Imidodiphosphate as Ligand in Fluoro Complexes. 1. Fluoro Complexes of TitaniumIn acetonitrile TiF4 reacts with tetraphenyl imidodiphosphate forming two tetrafluoro (I, II) and three trifluoro complexes (III, IV, V) as well as one difluorotitanium complex (VI). The difluoro complex VI is exclusively formed by sing an excess of the ligand. VI was isolated and analytically characterized. The constitution and configuration of the complexes are concluded from 19F and 31P n.m.r. data. The tetraphenyl imidodiphosphate is only bidentately bonded, i.e. as chelate or bridging ligand; in the substitution complexes III-VI it is coordinated as anion.
    Notes: TiF4 bildet mit Imidodiphosphorsäuretetraphenylester in CH3CN zwei Tetrafluoro- (I, II) und drei Trifluorokomplexe (III, IV, V) sowie einen Difluorotitan-Komplex (VI). Mit Ligandenüberschuß entsteht ausschließlich der Difluorokomplex, der isoliert und elementar-analytisch charakterisiert wurde. Die Konstitutions- und Konfigurationsaussagen zu den übrigen Komplexen basieren auf 19F- und 31P-NMR-Untersuchungen. Der Imidodiphosphorsäureestr ist in den Komplexen stets zweizähnig als Chelat- oder Brückenligand gebunden; in den Substitutions-komplexen III-VI ist er in seiner anionischen Form enthalten.
    Additional Material: 1 Tab.
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    Methylmetall-bis(trimethylsilyl)amidoderivate des Aluminiums, Galliums und Arsens (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 116-126 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Methyl Metal Bis(trimethylsilyl)amido Derivatives of Aluminium, Gallium, and ArsenicMeAl[N(SiMe3)2]2 (Me = CH3) has been prepared by the reaction of AlMe3 with HN(SiMe3)2 in a 1:2 molar ratio. The homologue Gallium compound (as well as the Aluminium derivative) is formed in good yields by the interaction of MeMcl2 (M = Al, Ga) with Li- and Na[N(SiMe3)2], respectively. MeAs[N(SiMe3)2]2 is formed by the reaction of AsCl3 and Na[N(SiMe3)2] in a 1:3 molar ratio. These colourless amido derivatives are monomeric in solution, they have been characterized by analyses, mass, n.m.r. (1H and 13C), and especially by i.r. and Raman spectra.
    Notes: MeAl[N(SiMe3)2]2 (Me = CH3) wurde durch Umsetzung von AlMe3 mit HN(SiMe3)2 im Molverhältnis 1:2 dargestellt. Die homologe Galliumverbindung (wie auch das Aluminiumderivat) bildet sich in guten Ausbeuten aus MeMCl2 (M =; Al, Ga) und Li- bzw. Na[N(SiMe3)2]. Schließlich entsteht MeAs[N(SiMe3)2]2 bei der Reaktion von AsCl3 mit Na[N(SiMe3)2] im Verhältnis 1:3. Diese farblosen Amidoderivate sind in Lösung monomer; sie werden elementar-analytisch, mit Hilfe der Massen- und NMR-Spektren (1H und 13C) sowie vornehmlich schwingungs-spektroskopisch (IR und Raman) charakterisiert.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19885630116
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    Polynuclear clusters of technetium. I. Synthesis, crystal and molecular structure of bromide octanuclear lrismatic and hexanuclear octahedral clusters of technetium (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 563 (1988), S. 136-152 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: mehrkernige Technetium-Cluster. I. Synthese, Kristall- und Molekularstruktur der Bromide achtkerniger prismatischer und sechskerniger oktaedrischer Cluster des TechnetiumsE werden die Synthese, Kristall- und Molekularstruktur erster Vertreter mehrkerniger Technetium-Cluster er Zusammensetzung: [Tc8Br4μ—Br8]Br. 2 H2O; [H(H2O)2][Tc8Br4μ—Br8]Br; [H(H2O)2]2[Tc8Br4μ—Br8]Br2; [H3O(H2O)3]2[Tc6Br6μ3—Br5]; [(C4H9)4N]2[Tc6Br6μ3—Br5]; [H3O(H2O)3]2[Tc6Br6μ3—Br5]. 4 H2O beschrieben. Diese Verbindungen unterscheiden sich in ihrem Bau wesentlich von bekannten Clustern anderer d-Elemente. Die Kristall- und Molekularstruktur von Hexabromotechnetiumsäure, (H3O)2TcBr6, ist untersucht worden.
    Notes: The synthesis, crystal and molecular structure of the first representatives of polynuclear technetium clusters are described. The composition of these clusters is: [Tc8Br4μ—Br8]Br. 2H2O; [H(H2O)2][Tc8Br4μ—Br8]Br; [H(H2O)2]2[Tc8Br4μ—Br8]Br2; [H3O(H2O)3]2[Tc6Br6μ3—Br5]; [(C4H9)4N]2[Tc6Br6μ3—Br5]; [H3O3]2[Tc6Br6μ3—Br5]. 4 H2O. It is shown that these clusters strongly differ in their structure from the known clusters of other d-elements. The crystal and molecular structure of hexabromotechetium acid (H3O)2TcBr6 is studied too.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19885630118
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    (Pentacarbonyl)wolfram-Komplexe von Diphosphanylacetylenen (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 567 (1988), S. 48-59 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (Pentacarbonyl)tungsten Complexes of Diphosphanyl AcetylenesPreparation and properties of the following compounds are described: (Pentacarbonyl)tungsten complexes of diamidophosphoryl-diaminophosphanyl acetylenes (3, 4), of diamidothiophosphoryl-diaminophosphanyl acetylenes (5, 6) and of bis(diaminophosphanyl)-acetylenemethiodides (7, 8). Furthermore, the (pentacarbonyl)tungsten complexes of numerous halogenated diphosphanyl acetylenes have been prepared (15-21). All compounds are characterized by their n.m.r., i.r., and partly their mass spectra. Of (Pentacarbonyl)bis[bis(diethylamino)phosphanyl]acetylenemethiodide tungsten, 7, the molecular and crystal structures are reported.
    Notes: Darstellung und Eigenschaften der folgenden Verbindungen werden beschrieben: (Pentacarbonyl)wolfram-Komplexe von Diamidophosphoryl-diaminophosphanyl-acetylenen (3, 4), von Diamidothiophosphoryl-diaminophosphanyl-acetylenen (5, 6) und von Bis(diaminophosphanyl)-acetylenmethiodiden (7, 8). Weiter wurden die (Pentacarbonyl)wolfram-Komplexe zahlreicher halogenierter Diphosphanyl-acetylene (15-21) dargestellt. Alle Verbindungen sind durch ihre NMR-, IR- und teilweise ihre Massenspektren charakterisiert. Von (Pentacarbonyl){bis[bis(diethylamino)phosphanyl]acetylenmethiodid}wolfram, 7, werden die Molekül- und Kristallstruktur mitgeteilt.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19885670106
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    Darstellung und Kristallstruktur von CsVHP3O10 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 567 (1988), S. 77-86 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structure of CsVHP3O10Hitherto unknown CsVHP3O10 crystallizes from melts prepared from Cs2CO3, V2O3 and H3PO4 (2 d at 350°C; cooling rate: 10°/h). Best yields were obtained at a molar ratio 1:1:3 of the components. According to an X-ray crystal structure determination (C2/c; a = 1208.7(5), b = 877.7(3), c = 894.4(3) pm, β = 110.76(3)°; Z = 4; R = 0.043) the title compound is a catena-triphosphate. Bond lengths and angles are compared to those of triphosphates investigated earlier.
    Notes: Vorher unbekanntes CsVHP3O10 kristallisiert aus Cs2CO3/V2O3/H3PO4-Schmelzen (2 d bei 350°C, Abkühlrate: 10°/h). Optimale Ausbeuten werden bei einem molaren Verhältnis der Komponenten von 1:1:3 erzielt. Nach der Kristallstrukturanalyse (C2/c; a = 1208,7(5), b = 877,7(3), c = 894,4(3) pm, β = 110,76(3)°; Z = 4; R = 0,043) liegt ein catena-Triphosphat vor. Die Bindungslängen und -winkel im Anion werden mit denjenigen früher untersuchter catena-Triphosphate verglichen.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19885670109
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    Zum Aufbau von A2[HgO2] (A = K, Rb), Rb2[NiO2] und Rb1,4K0,6[NiO2] [1-4] (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 567 (1988), S. 69-76 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Note on the Structure of A2[HgO2] (A = K, Rb), Rb2 [NiO2], and Rb1.4K0.6[NiO2]Single crystals of K2[HgO2] (I), Rb2[HgO2] (II), Rb2[NiO2] (III) and Rb1,4K0,6[NiO2] (IV) have been prepared [mercurates: colourless; niccolates: dichroitic ambercoloured/green (III) resp. yellow/green (IV)] mid characterized by X-riay single crystal methods. They crystallize tetragonally in the Na2[HgO2]-type of structure (space group I4/mmm, Z = 2) with I: a = 392.0(1), c = 1397.4(3) pm; II: a = 413.9(1), c = 1423.9(2) pm; III: a = 416.6(1), c = 1314.6(2) pm; IV: a = 409.2(2), c = 1304.4(6) pm. The crystal structures have been refined (four circle diffractometer). The Madelung parts of lattice energy, MAPLE, effective coordination numbers, ECoN, these via mean fictive ionic radii, MEFIR, are calculated and discussed.
    Notes: K2[HgO2] (I) wurde erneut, Rb2[HgO2] (II), Rb2[NiO2] (III) sowie Rb1,4K0,6[SiO2](IV) erstmals in einkristalliner Form dargestellt und röntgenographisch untersucht. Kristalle der Mercurate sind farblos, jene der Niccolate dichroitisch bernsteinfarben/grün (III) bzw. gelb/grün (IV). Die Oxide kristallisieren tetragonal im Na2[HgO2]-Typ (Raumgruppe I4/mmm, Z = 2) mit I: a = 392,0(1), c = 1397,4(3) pm; II: a = 413,9(1), c = 1423,9(2) pm; III: a = 416,6(1), c = 1314,6(2) pm; IV: a = 409,2(2), c = 1304,4(6) pm. Die Strukturparameter wurden verfeinert (Vierkreisdiffraktometerdaten). Der Madelunganteil der Gitterenergie, MAPLE, sowie Effektive Koordinationszahlen, ECoN, diese über Mittlere Fiktive Ionenradien, MEFIR, werden berechnet und diskutiert.
    Additional Material: 6 Tab.
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    URL: http://dx.doi.org/10.1002/zaac.19885670108
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    Properties of barium chlorophosphate (apatite) luminophors activated by divalent europiumDedicated to Professor Arthur Scharmann on the Occasion of his 60th Birthday (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 567 (1988), S. 60-68 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Eigenschaften von Bariumchlorophosphat (Apatit)-Leuchtstoffen bei Aktivierung mit zweiwertigem EuropiumEine Reihe von europiumaktivierten Barium- bzw. Calciumchlorophosphaten wurde in Pulverform dargestellt. Diese Leuchtstoffe sind isomorphe Vertreter der hexagonalen Chlorapatite (Ba, Ca, Mg)10(PO4)6Cl2. Neben Röntgendiffraktogrammen wurden Anregungs- und Emissionsspektren der Lumineszenz bei Zimmertemperatur und bei tiefen Temperaturen (T ∽ 4 K) untersucht. Steigender Calciumanteil beeinflußt die Lumineszenzeigenschaften dieser festen Lösungen durch Veränderung des am Eu2+-Ion wirkenden Kristallfelds. Das Erscheinen einer neuen Emissionsbande mit höherem Ca2+-Gehalt bei tiefen Temperaturen deutet auf Einbau der Eu2+-Ionen auf zwei verschiedenen Ba-Plätzen, so daß zwei Arten von Lumineszenzzentren auftreten. Die Lumineszenz entsteht durch Übergänge von der 4f65d- zur 4f7-Konfiguration des Eu2+.
    Notes: A series of powder materials of barium and calcium chlorophosphate activated by divalent europium have been prepared. These luminophors are isomorphous representatives of the hexagonal chlorapatites (Ba, Ca, Mg)10(PO4)6Cl2. In addition to x-ray diffractograms, excitation and emission spectra of luminescence have been studied at room and low temperatures (T ∽ 4 K). An increasing calcium content affects the luminescence properties of the solid solutions by changing the crystal field acting upon the Eu2+ ion. The appearance of a new low-temperature emission band with higher Ca2+ content indicates that the Eu2+ ions substitute on two different barium sites thus forming two types of luminescent centres. The luminescence arises from transitions between 4f65d and 4f7 configurations of Eu2+.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19885670107
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    Synthesen und Kristallstrukturen von CsM2P5O16 (M = V, Fe) (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 567 (1988), S. 87-94 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Crystal Structures of CsM2P5O16 (M = V, Fe)Upon heating of mixtures composed of Cs2CO3, H3PO4 and V2O3(Fe2O3) to 〉600°C, melts were formed, from which the title compounds crystallized during slow cooling. They form as well from CsVHP3O10 (CsFeHP3O10) by condensation, besides (CsPO3)n. According to crystal structure determinations (Pn; for M = V: a = 753.79(7), b = 941.05(12), c = 1 017.29(12) pm, β = 111.16(9)°; for M = Fe: a = 752.99(17), b = 937.77(44), c = 1 020.90(18) pm, β = 111.02(1)°; Z = 2) the anionic part of both compounds consists of catena-pentaphosphate groups. Systematic variations in the P—O bond lengths are discussed.
    Notes: Durch Erhitzen von Gemengen aus Cs2CO3, H3PO4 und V2O3(Fe2O3) auf 〉600°C entstehen Schmelzen, aus denen bei langsamem Abkühlen die vorher unbekannten Titelverbindungen kristallisieren. Sie bilden sich auch bei der thermischen Kondensation von CsVHP3O10 (CsFeHP3O10), wobei als Nebenprodukt (CsPO3)n anfällt. Nach der Röntgenstrukturanalyse (Pn; für M = V: a = 753,79(7), b = 941,05(12), c = 1 017,29(12) pm, β = 111,16(;9)° für M = Fe: a = 752,99(17), b = 937,77(44), c = 1 020,90(18) pm, β = 111,02(1)°; Z = 2) handelt es sich um catena-Pentaphosphate. Die systematische Variation der P—O-Bindungslängen im Anion wird diskutiert.
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    URL: http://dx.doi.org/10.1002/zaac.19885670110
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    Na2H3IO6, eine Variante der Markasitstruktur (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 567 (1988), S. 95-100 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Na2H3IO6, a Variant of the Marcasite StructureSingle crystals of Na2H3IO6 were grown for the first time. According to the results of an X-ray crystal structure determination(Pnnm; a = 469.7(3), b = 529.9(2), c = 1005.2(6) pm; Z = 2; 296 diffractometer data; RW = 0.051) iodine is in an octahedral coordination. Sodium is surrounded by six oxygen in a strongly distorted octahedral arrangement. IO6 and NaO6 groups are linked via common vertices and edges in the sense of the rutile or marcasite type of structure. The corresponding structural relationship is discussed.
    Notes: Erstmals wurden Einkristalle von Na2H3IO6 erhalten. Nach der Röntgen-strukturanalyse (Pnnm; a = 469,7(3), b = 529,9(2), c = 1005,2(6) pm; Z = 2; 296 Diffraktometerdaten, RW = 0,051) ist Iod oktaedrisch und Natrium stark verzerrt oktaedrisch von Sauerstoff koordiniert. Die Verknüpfung der Oktaeder erfolgt im Sinne der Rutil- bzw. Markasitstruktur; die entsprechende Strukturverwandtschaft wird diskutiert.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19885670111
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    NMR investigations on Stannabicycloundecanes of the type RSn(CH2CH2CH2)3N (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 567 (1988), S. 122-130 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: NMR-Untersuchungen an Stannabicycloundecanen des Typs RSn(CH2CH2CH2)3NEs werden 1H-, 13C- und 119Sn-NMR-Daten von sieben Stannabicycloundecanen des Typs RSn(CH2CH2CH2)3N (1, R = Cl; 2, R = Br; 3, R = I; 4, R = OH; 5, R = SPh; 6, R = Me; 7, R = Sn(CH2CH2CH2)3N) mitgeteilt. Aus den Protonen-NMR-Koaleszenzdaten bei tiefer Temperatur wird ΔGTc* für die Racemisierung des Bicyclo[3.3.3]-Gerüstes zu 37 ± 1 kJ/mol bestimmt. Die Werte sind unabhängig vom Substituenten R. In den entsprechenden Siliciumderivaten (R = Me) werden geringere Aktivierungsparameter gefunden.
    Notes: The 1H, 13C, and 119Sn NMR data of seven stannabicycloundecanes of the type RSn(CH2CH2CH2)3N (1, R = Cl; 2, R = Br; 3, R = I; 4, R = OH; 5, R = SPh; 6, R = Me; 7, R = Sn(CH2CH2CH2)3N) are reported. From 1H NMR coalescence data at low temperature the free activation enthalpies for the racemisation of the bicyclo[3.3.3]skeleton were estimated to be 37 ± 1 kJ/mol. They are independent of the substituent R. However, it decreases when the tin atom is replaced by silicon for R = Me.
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    URL: http://dx.doi.org/10.1002/zaac.19885670114
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    Monohalogenobenzoylhydrazones. V. Spectral and Bonding Properties of Some Novel Antimony(III) Complexes of p-chlorobenzoyl-di-(2-pyridyl)ketohydrazone studied by experimental and quantum-chemical methods (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 567 (1988), S. 161-172 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Monohalogenobenzoylhydrazone. V. Spektroskopische Untersuchungen und Bindungs-verhältnisse einiger neuer Antimon(III)-Komplexe von p-Chlorobenzoyl-di-(2-pyridyl)-ketohydrazon mittels experimenteller und quantenchemischer MethodenBei der Reaktion von Antimon(III)-chlorid, -bromid und -iodid mit dem p-Chlorobenzoylhydrazon des Di-(2-pyridyl)keton (DpClBHH) in methanolischer Lösung werden Komplexe des Typs SbX2(DpClBH) erhalten. Die Struktur dieser Verbindungen wird an Hand der spektroskopischen Daten diskutiert. Der Ligand koordiniert dreizähnig über die Carbonyl- und Azomethin-Gruppe sowie über den Stickstoff der Pyridyl-Gruppe. Eine verzerrt oktaedrische Koordination des Metalls wird vorgeschlagen. EH-MO-Rechnungen wurden zur Analyse der Elektronen-spektren und der Bindungsverhältnisse herangezogen. Weiterhin dienen Grenzorbital-Betrachtungen aus CNDO/2-Rechnungen zur Klärung der Metall-Liganden-Bindung.
    Notes: Reactions of antimony(III) chloride, bromide, and iodide with p-chlorobenzoylhydrazone of di-(2-pyridyl)ketone (DpClBHH) in methanolic solutions afford the complexes SbX2(DpClBH). The structures of the new compounds are discussed in relation to their spectroscopic properties. In these complexes the ligand behaved as terdentate, coordination occuring through the carbonyl and azomethine groups, as well as the nitrogen atom of the pyridyl group. Consequently, a distorted octahedral environment around the metal is proposed. Moreover, EHMO calculations have been used in the analysis of the bonding in the SbCl2(DpClBH) complex, as well as to interpret the electronic spectral data. In addition, CNDO/2 calculations performed on the aforesaid ligand have been used to throw light on the mode of attachment of the ligand to the metal ion by means of some quantum-chemical indices related to the frontier MO's.
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    URL: http://dx.doi.org/10.1002/zaac.19885670118
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    Mößbauer-Untersuchungen von Thiospinellen. VII. Das System Cd0,9Fe0,1Cr2(SxSe1-x)4 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 567 (1988), S. 173-178 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mössbauer Studies of Thiospinels. VII. The System Cd0.9Fe0.1Cr2(SxSe1-x)4In order to investigate the influence of mixed anions on 57Fe-Mössbauer spectra of thiospinels with tetrahedral FeII polycrystalline samples of the spinel system Cd0.9Fe0.1Cr2(SxSe1-x)4 have been prepared in the range 0.22 ≤ x ≤ 1. Room temperature Mössbauer spectra consist of several overlapping doublets of almost identical isomer shifts but different quadrupole splittings. The FeII-doublets are attributed to the five different coordination polyhedras S4, S3Se, S2Se2, SSe3, and Se4.
    Notes: Um den Einfluß eines gemischten Anionengitters auf die 57Fe-Mößbauer-Spektren von Thiospinellen mit tetraedrischem FeII zu untersuchen, wurden von dem spinell-system Cd0,9Fe0,1Cr2(SxSe1-x)4 im Bereich 0,22 ≤ x ≤ 1 polykristalline Proben hergestellt. Die Raumtemperatur-Mößbauer-Spektren der Spinellmischkristalle bestehen aus mehreren überlappenden Dubletts nahezu gleicher Isomerieverschiebung aber verschiedener Quadrupolaufspaltung. Die FeII-Dubletts können den Koordinationspolyedern S4, S3Se, S2Se2, SSe3 und Se4 zugeordnet werden.
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    URL: http://dx.doi.org/10.1002/zaac.19885670119
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    Zur Charakterisierung des Extragitter-Aluminiums in Y-Zeolithen mittels der FerronmethodeVgl. auch Z. Chem. 27 (1987) 194. (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 567 (1988), S. 145-152 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Characterization of Non-Framework Aluminium in Zeolites Y by the Ferron MethodBy using the ferron method it is shown that the non-framework aluminium occuring in dealuminated zeolites Y exists in form of different kinds of Al-oxo-hydroxo-species. At the beginning of dealumination (673 K) besides polymeric species with relatively low degree of polymerization monomeric and a special kind of oligomeric cations occur. These special cations alter into a mixture of oligomeric species with increasing temperature of dealumination (813 K). Simultaneously the degree of polymerization of the polymeric species increases.
    Notes: Mit der Ferronmethode wird gezeigt, daß das in thermisch behandelten Y-Zeolithen auftretende Extragitter-Aluminium aus unterschiedlichen Arten von Al-oxo-hydroxo-Spezies besteht. Am Anfang der Dealuminierung (673 K) liegen neben monomeren spezielle oligomere Kationen vor; gleichzeitig werden aber auch polymere Spezies mit relativ niedrigem Polymerisationsgrad gebildet. Mit steigender Temperatur der thermischen Behandlung (813 K) entsteht aus den oligomeren Teilchen ein Gemisch niedermolekularer Kationen. Die polymeren Spezies unterliegen dabei einer Veränderung im Sinne einer zunehmenden Kondensation bzw. Polymerisation.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19885670116
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    Über Chalkogenolate. 188. Darstellung und Eigenschaften von Estern der Dithiopropionsäure (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 47-53 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Chalcogenolates. 188. Preparation and Properties of Esters of Dithiopropionic AcidThe orange colored title compounds C2H5—CS—SR with R = CH3, C2H5, C(CH3)3, and CH2—C6H5 have been prepared in one-pot synthesis by reaction of ethyl bromide with magnesium followed by CS2 insertion and alkylation with the corresponding alkyl halide. Their electron absorption, infrared, nuclear magnetic resonance, and mass spectra are communicated.
    Notes: Die orangefarbene Titelverbindungen C2H5—CS—SR mit R = CH3, C2H5, C(CH3)3 und CH2—C6H5 wurden im Eintopfverfahren durch Umsetzung von Ethylbromid mit Magnesium, anschließender CS2-Insertion und Alkylierung mit dem entsprechenden Alkylhalogenid hergestellt. Ihre Elektronenabsorptions-, Infrarot-, Kernresonanz- und Massenspektren werden mitgeteilt.
    Additional Material: 5 Tab.
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    URL: http://dx.doi.org/10.1002/zaac.19885650106
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  • 86
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    Ein ungewöhnliches H-Brückenbindungssystem in Rubidium-hydroxiddihydrat, RbOH · 2 H2O (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 34-40 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: An Unusual System of Hydrogen Bonds in Rubidium Hydroxide Dihydrate, RbOH · 2 H2ORbOH · 2H2O was obtained by the reaction of Rb with H2O and dehydration of the resulting solution by concentrated sulfuric acid. The compound melts at 310 K. The structure was determined by X-ray single crystal methods: The H positions of H2O were found. The structure consists of a threedimensional H-bonded network of H2O molecules and OH-ions. Hydroxide ions are acceptors for four protons of four adjacent water molecules with d(O—O) = 2×2.59 Å and 2×2.82 Å. Oxygen of OH-ions is disordered over a distance of 1.27 Å. Rb has 8 H2O molecules as nearest neighbours, d(Rb—O) = 3.03 Å to 3.07 Å, OH-ions are further removed with d(Rb—O) ≥ 3.45 Å.
    Notes: RbOH · 2H2O wird durch Umsetzung von Rb mit H2O und Entwässern der entstehenden Lösung über konzentrierter H2SO4 erhalten. Die Verbindung schmilzt bei 310 K. An Einkristallen wurde ihre Struktur röntgenographisch bestimmt: Die H-Lagen an den H2O-Molekülen konnten ermittelt werden. Die Struktur zeigt ein brückengebundenes Gerüst von H2O-Molekülen und OH--Ionen. Die Hydroxidionen dienen als Akzeptoren für je ein Proton von vier benachbarten H2O-Molekülen mit d(O—O) = 2×2,59 Å und 2×2,82 Å. Der Sauerstoff des OH--Ions ist fehlgeordnet mit einem Abstand von 1,27 Å. Rb hat 8 H2O-Moleküle als nächste Nachbarn, d(Rb—O) = 3,03 bis 3,07 Å, OH--Ionen sind weiter entfernt mit d(Rb—O) ≥ 3,45 Å.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19885650104
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  • 87
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    Zur Darstellung und Struktur von M1—LnTa3O9 (Ln = Pr, Nd) Röntgenographische und elektronenmikroskopische Untersuchungen (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 54-66 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Structure of M1—LnTa3O9 (Ln = Pr, Nd), X-Ray and Electronmicroscopical InvestigationsNew ternary compounds M1—LnTa3O9 (Ln = Pr, Nd) could be prepared by chemical transport reaction in a temperature gradient T2 → T1 (T2 = 1100°C; T1 = 1000°C; CI2 as transport agent). M1 NdTa3O9 crystallizes in the monoclinic space group P 21/m with a = 5.3840(9) Å, b = 7.550(1) Å, c = 8.1911(9) Å and β = 92.46(1)°. The structure was refined to give R = 6.29% and Rw = 6.20%. It is built of double and single chains of corner-sharing TaO6 octahedra extended along the b-axis. Tunnels running along [010] are created by the framework of TaO6 octahedra. Ln (Ln = Pr, Nd) is located in these tunnels to levels of y = 1/4 and 3/4. A structure refinement for isostructural M1—PrTa3O9 led to a = 5.4051(7) Å, b = 7.5680(2) Å, c = 8.1964(9) Å, β = 92.38(2)° and R = 7.72%, Rw = 7.57%. By grinding in an agate mortar M1—LnTa3O9 transforms into M2—LnTa3O9, a new modification with a higher density.High resolution transmission electron microscopy images of the M1—PrTa3O9 structure were made along the [010] direction. They could be interpreted by comparing them with images calculated on the basis of the multi-slice method.
    Notes: Durch chemischen Transport im Temperaturgefälle T2 → T1 (T2 = 1100°C; T1 = 1000°C) mit dem Transportmittel Chlor (p(Cl2; 20°C) = 1 atm) wurden die neuen Verbindungen M1—LnTa3O9 (Ln = Pr, Nd) erhalten. Die Strukturbestimmung über Einkristalldaten ergab für M1—NdTa3O9: RG P21/m;a = 5,3840(9) Å, b = 7,550(1) Å, c = 8,1911(9) Å, β = 92,46(1)°; Z = 2; R = 6,29%, Rw = 6,20%. Es liegen TaO6-Oktaeder vor, die allseitig über Ecken miteinander verknüpft und zum Teil auch über Kanten zu Oktaederpaaren verbunden sind. In Richtung [010] wechseln sich Oktaeder und Oktaederpaare ab. In den längs b verlaufenden Kanälen zwischen den Oktaederpaaren befinden sich die Nd-Teilchen. Die Strukturverfeinerung am isotypen M1—PrTa3O9 führte zu den Gitterkonstanten a = 5,4051(7) Å, b = 7,5680(2) Å, c = 8,1964(9) Å, β = 92,38(2)° und R = 7,72%, Rw = 7,57%.Beim Zerreiben der Kristalle von M1—LnTa3O9 (Ln = Pr, Nd) erfolgt eine tribochemische Umwandlung in eine weitere neue Modifikation M2—LnTa3O9 mit signifikant höherer Dichte.Von M1—PrTa3O9 konnten hochaufgelöste elektronenmikroskopische Durchstrahlungsaufnahmen längs [010] erhalten werden. In Übereinstimmung mit der rechnerischen Kontrastsimulation sind die unbesetzten Kanäle bei einem Defokus von -1150 Å deutlich als heller Kontrast erkennbar.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19885650107
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  • 88
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    Zur Darstellung und Struktur neuer Modifikationen von CeTa3O9 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 67-80 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Structure of New CeTa3O9 ModificationsThe modifications M—, O— and P—CeTa3O9 could be prepared by chemical transport reactions (T2 → T1; T2 = 1100°C; T1 = 1000°C) with chlorine as transport agent.M—CeTa3O9 crystallizes in the monoclinic space group C 2/m with a = 12.415(1) Å, b = 7.6317(8) Å, c = 6.5976(8) Å, β = 93.31(1)°; Z = 4; R = 4.88%, Rw = 3.67%. The structure consists of two types of Ta—O-polyhedra. Especially remarkable are chains of edge sharing pentagonal TaO7-bipyramids which are connected by TaO6-octahedra at opposite sides. Tunnels running along [010] are created by the framework of Ta—O-polyhedra and are filled with Ce in levels of y = 1/2 and y = 0.O—CeTa3O9 crystallizes orthorhombically with a = 6.5429(7) Å, b = 7.6491(7) Å, c = 12.583(1) Å and is isostructural to O—LaTa3O9 (space group: Pnma). O—CeTa3O9 contains the same characteristic structural units namely pentagonal TaO7-bipyramides and TaO6-octahedra. The difference between O— and M—CeTa3O9 is based on the orientation of the tunnels: in the orthorhombic modification they are arranged zigzag-like, in the latter parallel.Both modifications of CeTa3O9 can be irreversibly converted into the well-known perovskite-related P—CeTa3O9 structure with a lower density by heating in air to 1200°C.
    Notes: Durch chemischen Transport (T2 → T1; T2 = 1100°C; T1 = 1000°C) mit dem Transportmittel Chlor (p(Cl2; 298 K) = 1 atm) wurden Kristalle der neuen Modifikationen M— und O—CeTa3O9 sowie von der Perowskitvariante P—CeTa3O9 erhalten. Nach der Strukturbestimmung über Einkristalldaten ist M—CeTa3O9 monoklin (C 2/m) mit a = 12,415(1) Å, b = 7,6317(8) Å, c = 6,5976(8) Å, β = 93,31(1)°; Z = 4; R = 4,88%, Rw = 3,67%. Man erkennt aus kantenverknüpften pentagonalen TaO7-Bipyramiden bestehende Bänder längs c, die miteinander durch TaO6-Oktaeder verbunden sind. In den so gebildeten Kanälen sind die Cer-Teilchen lokalisiert.O—CeTa3O9 kristallisiert orthorhombisch mit a = 6,5429(7) Å, b = 7,6491(7) Å, c = 12,583(1) Å und ist nach Pulveraufnahmen isotyp mit der bereits näher untersuchten Verbindung O—LaTa3O9. Beide orthorhombischen Oxide sind wie M—CeTa3O9 durch ein Netzwerk kantenverknüpfter TaO7- und TaO6-Polyedern gekennzeichnet; in [010]-Richtung liegen nur Eckenverknüpfungen vor. Die TaO6-Oktaeder sind in der a—c-Ebene jeweils so angeordnet, daß die mit Ce (La) besetzten Kanäle bei O—CeTa3O9 zick-zack-förmig, bei M—CeTa3O9 parallel zueinander orientiert erscheinen.O— und M—CeTa3O9 zeigen beim Erhitzen (1200°C; an Luft) eine nicht reversible Umwandlung in die bekannte Perowskitmodifikation P—CeTa3O9 (Ce1/3TaO3) mit deutlich geringerer röntgenographischer Dichte.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19885650108
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  • 89
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    Zum Aufbau von NaRhO2 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 106-110 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Structure of NaRhO2For the first time black single crystals of NaRhO2 (from Li2O, NAO0,50 α-Rh2O3, Li: Na: Rh = 1,15:2.18:1, Pd-cylinder, 950°C, 18 d, in 18 d cooled down) have been prepared and investigated by X-ray. NaRhO2 crystallizes in the α-NaFeO2-type: a = 309.71(4), c = 1552,75(34) pm, c/a = 5.01, space group R3m, Z = 3; fourcircle diffractometer data (Philips PW 1100): 124 of 126 I0(hkl): AgKα; R = Rw = 3.44%). The Madelung Part of Lattice Energy, MAPLE, and peculiarities of this type of structure are discussed.
    Notes: Erstmals wurden schwarze Einkristalle von NaRhO2 (aus Li2O, NaO0,50 und α-Rh2O3, Li: Na: Rh = 1,15:2,18:1, Pd-Bömbchen, 950°C, 18 d, 18 d abgekühlt) dargestellt und röntgenographisch untersucht. NaRhO2 kristallisiert im rhomboedrischen α-NaFeO2-Typ: a = 309,71(4), c = 1552,75(34) pm, c/a = 5,01, Raumgruppe R3m, Z = 3; Vierkreisdiffraktometerdaten (Philips PW 1100): 124 von 126 I0(hkl); AgKα; R = Rw = 3,44%). Der Madelunganteil der Gitterenergie, MAPLE, und Charakteristika des Strukturtyps werden diskutiert.
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    URL: http://dx.doi.org/10.1002/zaac.19885650111
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  • 90
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    Chlor-Fluor-Austausch an halogenierten 1,3-Disilazanen (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 81-90 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chloro-Fluro-Exchange by Halogenated 1.3-DisilazanesAminofluorosilance (1-4) are obtained in the reaction of difluorosilanes with lithiated amines. Disilazanes (5,6) are formed in the reaction of LiNH(C6H3-iPr2) with CMe3SiF3 and C6H5SiF3. Lithium salts of 1-4 are dimers in n-hexane (7-10) and LiF adducts of iminosilanes in THF (11-14). The latter react with chlorsilanes (RSiCl3, R = Cl, H, Me) to give the substituted compounds 15-21 and LiCl. An intermolecular F/Cl exchange occurs with 15-20 which depends on the temperature, the solvents and ligands. 22-27 are formed.
    Notes: Aminofluorsilance (1-4) werden durch die Reaktion der Difluorsilane mit lithiierten Aminen erhalten. CMe3SiF3 und C6H5SiF3 reagieren zu Disilazanen (5,6). Die Lithiumsalze von 1-4 bilden in n-Hexan Dimere (7-10) und in THF LiF-Addukte von Iminosilanen (11-14). Letztere reagieren mit Chlorsilanen (RSiCl3, R = Cl, H, Me) unter LiCl-Abspaltung und Substitution zu 15-21 . 15-20 unterliegen einem intermolekularen F/Cl-Austausch, der temperatur-, lösungsmittel- und substituentenabhängig ist. Es entstehen 22-27 .
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19885650109
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  • 91
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    Schwefeldioxid als Ligand und Synthon. VII. Phosphan-Schwefeldioxid-Nickel(0)- und Palladium(0)-Komplexe (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 91-105 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sulfur Dioxide as Ligand and Synton. VII. Phosphane Sulfur Dioxide Nickel (0) and Palladium (0) ComplexesSynthesis and properties of phosphane sulfur dioxid d10-metal complexes of the types ML2(SO2)2, ML2(SO2), and ML3(SO2) (M = Ni(0), Pd(0); L = t-phosphane) are described. In dependence on the phosphane coligands nickel(0) complexes with η1-planar, η1-pyramidal and η2-S.O. (side on) coordinated SO2 are formed. In the case of the palladium(0)-SO2 complexes hithero prepared the dominating coordination mode is the η1-pyramidal one.
    Notes: Synthese und Eigenschaften von Phosphan-Schwefeldioxid-d10-Metallkomplexen der Typen ML2(SO2)2, ML2(SO2) und ML3(SO2) (M = Ni(0), Pd(0); L = t-Phosphan) werden beschrieben. In Abhängigkeit der Phosphan-Coliganden entstehen Nickel(0)-SO2-Komplexe mit η1-planar, η1-pyramidal und η2-S.O (side on) koordiniertem SO2. Dagegen dominiert im Falle der bislang dargestellten Palladium(0)-SO2-Komplexe die η1-pyramidale Koordinationsgeometrie.
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    URL: http://dx.doi.org/10.1002/zaac.19885650110
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  • 92
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    Untersuchungen zur Anionenkonstitution in Mischungen aus Diethyl-di(2-hydroxyethyl)ammonium-und Triethyl-(2-hydroxyethyl)ammoniumsilicatlösungen Bildung von Diethyl-di (2-hydroxyethyl)ammonium-/Triethyl-(2-hydroxyethyl)ammoniumsilicathydraten (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 118-126 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations of the Anion Constitution in Mixtures of Diethyl-di(2-hydroxyethyl)ammonium and Triethyl-(2-hydroxyethyl)ammonium Silicate Solutions. Formation of Diethyl-di(2-hydroxyethyl)-/Triethyl- (2-hydroxyethyl)ammonium Silicate HydratesOrganoammonium silicate solutions with a molar ratio base to silicon dioxide of 2 to 1 (cSiO2 =.1 and 1.7 mol · kg-1) and 1 to 1 (cSiO2 = 2.5 mol · kg-1) have been investigated with various amount of diethyl-di(2-hydroxyethyl)- and triethyl-(2-hydroxyethyl)ammonium hydroxide. Double-three and double-four ring silicate ions have been found in all solutions by 29Si n.m.r. spectroscopy. The amount of double-four ring species increases with increasing amount of diethyl-di-(2-hydroxyethyl)ammonium hydroxide. The substances crystallized are organoammonium double-four ring silicate hydrates, in which both of the mentioned base cations are present.
    Notes: Untersucht werden Organoammoniumsilicatlösungen mit einem molaren Verhältnis Base zu Siliciumdioxid von 2 zu 1 (SiO2-Konzentration von 1,1 und 1,7 mol · kg-1) und 1 zu 1 (SiO2-Konzentration von 2,5 mol · kg-1), wobei als Basekomponente unterschiedliche Anteile an Diethyl-di(2-hydroxyethyl)- und Triethyl-(2-hydroxyethyl)ammoniumhydroxid vorliegen. In allen Lösungen werden 29Si-NMR-spektroskopisch Doppeldreiring- und Doppelvierringsilicationen nachgewiesen, der Gehalt an Doppelvierringspezies erhöht sich mit steigendem Anteil an Diethyl-di(2-hydroxyethyl)ammoniumhydroxid. Auskristallisierende Substanzen sind Organoammonium-Doppelvierring-Silicathydrate, in denen stets beide Basekationen nebeneinander vorliegen.
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    Compound Formation in the System TeO2—Ta2O5 (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 127-136 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Verbindungsbildung im System TeO2—Ta2O5Drei Verbindungen existieren im System TeO2—Ta2O5: 3TeO2 · Ta2O5 (tetragonal), 2TeO2 · Ta2O5 (tetragonal und orthorhombisch) und TeO2 · 3Ta2O5 (orthorhombisch). Es wird gezeigt, daß die bisher als 7TeO2 · 3Ta2O5 und 2TeO2 · Ta2O5 (Hochtemperaturform) bezeichneten Verbindungen die stabilen Modifikationen von 2TeO2 · Ta2O5 (orthorhombisch) bzw. TeO2 · 3Ta2O5 sind.
    Notes: Three compounds exist in the system TeO2—Ta2O5: 3TeO2 · Ta2O5 (tetragonal), 2TeO2 · Ta2O5 (tetragonal and orthorhombic), and TeO2 · 3Ta2O5 (orthorhombie). The compounds previously denoted as 7TeO2 · 3Ta2O5 and 2TeO2 · Ta2O5 (high-temperature form) are shown to be stable modifications of 2TeO2 · Ta2O5 (orthorhombie) and TeO2 · 3Ta2O5, respectively.
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    URL: http://dx.doi.org/10.1002/zaac.19885650114
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    Cobaltchelate als Hydrierkatalysatoren. VI. Spektralphotometrische Untersuchung der Adduktbildung des [Co(dpnH)]+-Komplexes mit Pyridin (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 137-146 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cobalt Chelates as Hydrogenation Catalysts. VI. Spectrophotometric Investigation of the Adduct Formation of [Co(dpnH)]+ with PyridineThe investigation of the adduct formation of the [Co(dpnH)]+ complex with pyridine by spectrophotometric measurements causes some difficulties due to the unfavourable overlapping of the spectra of the starting complex, the mono- and the bis-adduct in the spectral range used (17000-32000 cm-1). Therefore, the adduct formation constant β2 can only be determined, if the waveleagths for the evaluation of the data are suitably selected. The thermodynamic parameters, calculated from the temperature dependence of β1 (δRH° = -9.1 ± 0.5 kJ · mol-1, δRS° = -5.6 ± 1.7 J · mol-1 · K-1), differ clearly from those which have been obtained from kinetic measurements [3]. The reason for this difference, which is quite beyond the error limit of the applied methods, is most probably the neglect of analogous adduct equilibria with the solvent.
    Notes: Die Untersuchung der Adduktbildung des [Co(dpnH)]+-Komplexes mit Pyridin durch spektralphotometrische Messungen bereitet Schwierigkeiten, da sich die Spektren des Ausgangskomplexes, des Mono- und des Bis-Addukts im untersuchten Spektralbereich (17000-32000 cm-1) ungünstig überlagern. Die Adduktbildungskonstante β2 läßt sich daher nur ermitteln, wenn die Wellenzahlen für die Auswertung der Messungen geeignet ausgewählt werden. Die aus der Temperaturabhängigkeit von β1 berechneten thermodynamischen Parameter (δRH° = -9,1 ± 0,5 kJ · mol-1, δRS° = -5,6 ± 1,7 J · mol-1 · K-1) unterscheiden sich jedoch deutlich von den Werten, die durch kinetische Messungen [3] bestimmt worden sind. Ursache für diese, weit außerhalb der Fehlergrenze der Methoden liegenden Differenzen ist sehr wahrscheinlich die Vernachlässigung von analogen Adduktgleichgewichten mit dem Lösungsmittel.
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    URL: http://dx.doi.org/10.1002/zaac.19885650115
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    Über die Chemie der Oxydation gasförmiger Gemische von C2F3Cl3, SiCl4, GeCl4 und POCl3 bei hohen Temperaturen (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 154-162 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: About the Chemistry of the Oxidation of Gaseous Mixtures of C2F3Cl3, SiCl4, GeCl4, and POCl3 at High TemperaturesThe formation of gaseous compounds during the oxidation of gaseous mixtures of C2F3Cl3, SiCl4, POCl3, and GeCl4 within a reactor of quartz glass was investigated in the temperature range from 1273 to 2223 K by infrared spectroscopy in the effluent gases. At the low temperature CO, COF2, COFCl, and CF4 are formed as intermediates, which react in contact with SiO2 at higher temperatures to the stable final products CO2, Cl2, SiF4, POF3, and GeF4. The dependence of these reactions on temperature and the velocity of the gases is discussed.
    Notes: Die bei der Oxydation von gasförmigen Gemischen von C2F3Cl3, SiCl4, POCl3 und GeCl4 im Temperaturbereich von 1273 bis 2223 K im Quarzglasreaktor entstehenden Verbindungen werden in den Abgasen IR-spektroskopisch untersucht. Danach entstehen bei der tiefen Temperatur als Zwischenprodukte CO, COF2, COFCl und CF4, die bei der hohen Temperatur unter Wechselwirkung mit SiO2 in die Endprodukte CO2, Cl2, SiF4, POF3 und GeF4 übergeführt werden. Die Abhängigkeit dieser Reaktionen von Temperatur und Strömungsgeschwindigkeit wird diskutiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19885650117
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  • 96
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    Synthese, thermisches Verhalten und Kristallstruktur von von [Ni(NH3)6][S(O)C=C(CN)2] · 1,5, H2O, einem Salz mit Nickel(II)-hexammin-Kationen (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 147-153 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Thermal Analysis, and X-Ray Crystal Structure of [Ni(NH3)6][S(O)C=C(CN)2] · 1.5 H2O, a Salt with the Nickel (II) Hexammine CationThe compound [Ni(NH3)6][S(O)C=C(CN)2] · 1.5 H2O is obtained by reaction of solutions of nickel acetate tetrahydrate in ammonia and K2[S(O)C=C(CN)2] · H2O in water. The salt crystallizes with the monoclinic space group P 21/a. The lattice constants are a = 15.183(1), b = 13.084(1), c = 14.386(1) Å, β = 100.96(7)° and Z = 8.The X-ray structure revealed two crystallographically independent nickel hexammine cations besides pseudochalcogenolate anions. The latter are associated with water molecules and exhibit strong delocalized π-electron systems.The thermal decomposition proceeds in three different steps. The first and second step refer to evolution of ammonia while in a third step H2O is squeezed out. This results in a decomposition of the substance.
    Notes: Die Verbindung [Ni(NH3)6][S(O)C=C(CN)2] · 1,5H2O ist durch Reaktion einer ammoniakalischen Lösung von Nickelacetat-Tetrahydrat mit K2[S(O)C=C(CN)2] · H2O, gelöst in Wasser, zugänglich. Das Salz kristallisiert monoklin mit der Raumgruppe P 21/a. Die Gitterkonstanten betragen a = 15,183(1), b = 13,084(1), c = 14,3886(1) Å, β = 100,96(7)° und Z = 8.Nach der Röntgenstrukturanalyse (R = 0,07, Rw = 0,06 für 1109 beobachtete Reflexe) liegen jeweils zwei kristallographisch verschiedene Nickelhexamminkationen neben Pseudochalkogenoanionen vor. Letztere sind ausschließlich mit Hydratwassermolekülen assoziiert und weisen mit ihren Bindungslängen auf stark delokalisierte π-Elektronensysteme hin.Die thermogravimetrische Analyse zeigt einen stufenförmigen Abbau der Solvensmoleküle, wobei zunächst in zwei Schritten Ammoniak entweicht. Der Abspaltung des Hydratwassers schließt sich die Zersetzung der Substanz an.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19885650116
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  • 97
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    Darstellung und IR-spektroskopische Untersuchungen von Silylaminosilanen (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 171-180 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and I.R. Spectroscopic Investigations of SilylaminosilanesThe silylaminosilanes Me3-n(Me3SiNH)nSiH (n = 1-3) and (RMe2SiNH)3SiH were prepared by coammonolysis of dimethylorganochlorosilanes RMe2SiCl with chlorohydridosilanes Me3-nClnSiH (n = 1-3). The reaction of chlorohydridosilanes Me3-nClnSiH (n = 2,3) with hexamethyldisilzane yields the resp. silylaminosilanes Me3-n(Me3SiNH)nSiH(n = 2,3).The i.r. and 1H-n.m.r. data of the compounds are given and the relative basicity were measured by means of the V(C—D) band shift of CDCl3 associated to the silylaminosilanes. A dependence of the frequency of the Si—H stretching vibration and the number of trimethylsilylamino groups in Me3-n(Me3SiNH)nSiH and the substituents R in (RMe2SiNH)3SiH was found. All the methyl(silylamino)silanes Me3-n(Me3SiNH)nSiH show the same basicity, whereas the basicity of tris(dimethyl-organosilylamino)silanes is mainly determined by the steric effect of the substituents R.
    Notes: Die Silylaminosilane Me3-n(Me3SiNH)nSiH (n = 1-3) und (RMe2SiNH)3SiH (R = Et, n-Bu, Ph, C6H5CH2) wurden durch Coammonolyse der Dimethylorgano-chlorsilane RMe2SiCl mit den Chlorhydridsilanen Me3-nClnSiH (n = 1-3) dargestellt. Die Reaktion der Chlorhydridsilane Me3-nClnSiH (n = 2,3) mit Hexamethyldisilazan ergibt die entsprechenden Silylaminosilane Me3-n(Me3SiNH)nSiH (n = 2,3).Die IR- und 1H-NMR-Daten der Verbindungen sind angegeben, und die relative Basizität wurde gemessen an der Bandenverschiebung Δ∼ der V(C—D)-Bande des CDCl3 bei Assoziation an die Silyl-aminosilane. Die Bandenlage der Si—H-Valenzschwingung zeigt eine Abhängigkeit von der Anzahl der Trimethylsilylaminogruppen in den Me3-n(Me3SiNH)nSiH und den Substituenten R in den (RMe2SiNH)3SiH. Die Basizität der Methyl-silylamino-silane Me3-n(Me3SiNH)nSiH ist gleich, die der Tris-(dimethylorganosilylamino)-silane (RMe2SiNH)3SiH wird vorwiegend durch den sterischen Effekt der Substituenten R bestimmt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19885650119
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  • 98
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    Vorberichte (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 192-192 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstracts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19885650121
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  • 99
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    Electronic Resource
    Masthead (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 566 (1988) 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19885660101
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  • 100
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    Electronic Resource
    Preparation, Chemical, and Structural Characterization of Some Molybdenum(III) and Tungsten(III) Coordination Compounds Containing 1-(4-pyridyl)pyridinium Cation (1988)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 565 (1988), S. 163-170 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Darstellung, chemische und strukturelle Charakterisierung von Molybdän(III)- Wolfram (III)-Komplexen mit 1-(4-pyridyl)pyridinium als Kation(Py2)HMoCl5 · H2O wurde aus der salzsauren Lösung von (NH4)2MoCl5 · H2O dargestellt ((Py2)H2+ = 1-(4-pyridyl)pyridinium-Ion, C10N2H102+). Diese nichtreaktive, luftbeständige Verbindung, kristallisiert orthorombisch. Die Gitterkonstanten sind: a = 12,895(4), b = 6,914(2), c = 16,388(7) Å, Z = 4. Die Elementarzelle enthält MoCl5 · H2O2-- Oktaeder und (Py2)H2+. Die Abstände Mo—Cl betragen 2,406(3) bis 2,446(4) Å. Die Bindung Mo—O(H2O) beträgt 2,19(1) Å. Der Winkel zwischen zwei Pyridinringen des Kations ist 38°. Die Anionen bilden Schichten auf den Ebenen mit Z = 1/4 und Z = 3/4. Zwischen den Schichten be-finden sich die (Py2)H2+-Kationen.(Py2)MX4Py2-Komplexe (M = Mo, W; X = Cl, Br; Py = Pyridin) mit deprotoniertem (Py2)H2+ als Kation, wurden aus den Lösungen von (PyH)MX4Py2 in konz. Ammoniak-Lösung durch Zusatz von (Py2)HCl2 hergestellt. Alle vier Verbindungen kristallisieren triklin. Die Gitterkonstanten sind vergleichbar. Die Stabilität gegen Oxydation und Substitution kann man der geringen Löslichkeit der Substanzen zuschreiben.
    Notes: 1-(4-pyridyl)pyridinium ion (C10H10N22+, (Py2)H2+) precipitates from the hydrochloric acid solution of (NH4)2MoCl5 · H2O sparingly soluble (Py2)HMoCl5 · H2O. This unreactive, air stable compound crystallizes in the orthorhombic unit cell with a = 12.895(4), b = 6.914(2), c = 16.388(7) Å, Z = 4. The ionic structure contains octahedral MoCl5 · H2O2- and (Py2)H2+. The bond lengths Mo—Cl are between 2.406(3) to 2.446(4) Å. The bond length Mo—O(H2O) is 2.19(1) Å. Planar pyridine rings of the cation are rotated around the common axis by 38°. Anions are located in layers at Z = 1/4 and 3/4. Between the layers (Py2)H2+ cations are situated.(Py2)MX4Py2 (M = Mo, W; X = Cl, Br; Py = Pyridine) with deprotonated (Py2)H2+ are prepared from the solutions of (PyH)MoX4Py2 in aqueous ammonia to which (Py2)HCl2 was added. All four compounds crystallize in the triclinic crystal system. Unit cell dimensions are comparable. The stability of the compounds against oxidation and substitution could have its origin in the low solubility.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19885650118
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