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  • 1995-1999
  • 1985-1989  (609)
  • 1870-1879
  • 1986  (609)
  • Organic Chemistry  (570)
  • Industrial Chemistry and Chemical Engineering
  • Nuclear reactions
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  • 1995-1999
  • 1985-1989  (609)
  • 1870-1879
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  • 1
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 43-43 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 68-73 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An optical particle counting system has been developed for testing industrial pulse-cleaned cartridge dust collectors. The system is applied to measure fractional penetration of a full scale dust collector and to study its short term and long term dynamic behavior. Results show collector efficiencies for dust loadings of 23 g/m3 exceeding 99.999% over the particle size range from 0.5 μm to 10 μm, with a minimum fractional penetration occurring at approximately 2 μm.
    Additional Material: 9 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986) 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 96-98 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 136-141 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: With the three-plate-capacitor method, as described previously by the author, reactions and heating processes in freely suspended particles (diameter 5-50 μm) were investigated by using the diffraction pattern of a laser beam. Change of weight can be registered, during operation, by the a. c. and d. c. voltage connected to a capacitor. This device enables information to be obtained, from inside the droplets, on the gradient of density or the precipitation of small particles and on the formation and solution process of a crystal nucleus in anorganic and low molecular organic substances. The behaviour of high polymer materials was studied during heating in the central region ca. 4 μm of the droplet.The diffraction patterns are similar to those of crystals (micells), but they do not show any crystal nucleus in the center. The application of heat, up to the softening point, gradually diffuses this cell arrangement. Such phenomena have not previously been studied within a droplet.
    Additional Material: 17 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 99-103 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The investigations of single and combined properties of particles or of particulate matter still belongs to the most important areas of present research and practical applications of Particle Characterization. Methods to measure single particle properties, as for instance particle size, shape, composition and velocity, are of much higher sophistication than before and they still aim at improved accuracy and higher resolution. There still is a considerable lack of understanding, and lack of theoretical interpretation and of experimental evidence of the differences seen in the correlation of different equivalent diameters, obtained when analysing the same irregularly shaped particle, or a distribution of particles, using different physical principles. Furthermore, there still is a lack of understanding of the influence of shape on the results obtained with optical methods using diffraction, light scattering etc., thus asking for more information with respect to the transferability of results from one physical principle to another. The measurement of combined particle properties comprises the simultaneous measurement of, for instance, size, velocity and concentration, which is of particular importance in the comprehensive description of multiphase flow systems. Those instruments which are in working order are highly complicated, not easy to use and to handle and they are in most cases special adaptations for a limited range of the variables to be analysed. There is also growing interest in the evaluation of socalled property functions. Particle Characterization will remain for quite a number of years just as exciting as it has been in the past. If industrial demand enforces the use of on-line instrumentation it might even become more interesting.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 129-135 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the field of material science, especially for polydisperse materials, many questions arise which cannot be answered sufficiently and precisely without information which represents the random character of the structure in space. Computer simulation is here an effective tool used to create random arrangements of particles which may be regarded as a realistic representation of the underlying material. Of course, the presumption that the shape of each particle is a sphere is an idealization which is a certain handicap in modeling all the possible system properties. Nevertheless, it can be demonstrated that, by having an adequate subroutine, many phenomena which are influenced by the local topology of the particles and their interaction forces can be studied in more detail.
    Additional Material: 10 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 145-150 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Miniaturized sieves (1/2 inch diameter) can be mounted in a spinning riffler system to obtain small representative powder samples which eventually can be sieved in situ without removing the miniature sieves from the riffler system. By mounting several different aperture sieves around the riffler a confederation of miniature sieves could replace nest sieving. The sieving surface for these new sieves is so small compared to that of the traditional eight inch sieve that one could consider using the more expensive electroformed sieving surfaces for all test sieves in the quality control laboratory.
    Additional Material: 12 Ill.
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  • 10
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 168-173 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Loosened bulk materials occur, for example, during grinding in a tube mill. Thus, a rheological study of bulk granular materials which are loosened by fluidisation should lead to a better characterization of the flow and conveying properties of the material when ground in the mill.For this measurement of fluidised bulk materials an agitating device and a rotary viscosimeter have been developed, designed and tested.First results are presented and discussed showing the fluidisation behaviour and density of the bulk material as a function of grain size as well as the flow properties as a function of the grain size and degree of fluidisation.Finally, a projection of further research work is given.
    Additional Material: 14 Ill.
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  • 11
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 14-19 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This study deals with measurements of the drop-size distributions of different types of fan spray atomisers using a scattered-light particle size counting analyser. The drop-size distributions were determined at various locations in the spray cone. These local distributions change systematically from the fan's axis to its border. Superimposing these local distributions, adequately weighted, one acquires the entire distribution of all the drops. A comparison of the experimental results is made with those yielded by mathematical equations.
    Additional Material: 8 Ill.
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  • 12
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 1-7 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The performance of a narrow-angle and a wide-angle, forward scattering laser aerosol spectrometer has been studied as a function of particle size and refractive index. The results have been compared with theoretical calculations based on light scattering theory. The results indicate that for the narrow-angle instrument, the scattered-light intensity is not a monotonic function of particle size for transparent particles (a monotonic relationship is required for unambiguous particle size measurement) above 0.7 μm. The instrument is therefore limited in its useful range to size distribution measurement between 0.2 μm - its lower particle size limit - and 0.7 μm for transparent particles. In the case of the wide-angle instrument, the instrument output is a monotonic function of particle size for transparent particles, but the output is severely attenuated for light absorbing particles above 0.3 μm. The instrument, therefore, cannot be used for accurate size measurements above 0.3 μm for light absorbing particles.
    Additional Material: 12 Ill.
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  • 13
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 20-25 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Starting from Wheeler's composite theory, which takes both the multilayer adsorption and the capillary condensation into consideration, and assuming the equivalent cylindrical model, we have deduced a strict and relatively simpler formula for the calculation of pore size distribution by solving the integral equation directly. The formula is more convenient for application because of its recursion form. Following the same line of reasoning and using the mean value theorem of definite integrals under different conditions, we have unified the equations of Barrett-Joyner-Halenda, Dubinin, Cranston-Inkley, Dollimore-Heal and Roberts. A table of parameters which is required in the calculation is given. Besides the adsorption of nitrogen, the adsorption with water vapor as the adsorbate is investigated and the corresponding empirical equation of adsorption thickness is given.
    Additional Material: 2 Ill.
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  • 14
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986) 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 15
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 63-67 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Locked particles are defined as those comminuted or particles which contain both gangue and target material. By considering the shape of the comminuted particles and assuming their random distribution in the ore body prior to comminution, it is possible to derive locking profiles which give the frequency of occurrence of particles which have a given fraction of their volume occupied by target material. For most particle shapes (spheres, angular particles, angular plates and rods) the locking profile is a deep U-shaped curve. This suggests that few particles by number contain about 50% target material while a far greater number contain either very little or very much target material. Such a conclusion is important in planning separation processes for locked particles in the mineral industry.
    Additional Material: 5 Ill.
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  • 16
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 56-62 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Latices of 2, 4 and 9 μm diameter intended for use a particle standard have been examined under a variety of storage and handling conditions. The effects of light exposure, temperature variation and storage in isotonic saline were studied as well as the handling conditions, such as multiple sampling, dispersion technique and effects of foaming. Particle sizes and particle number densities were remarkably constant, even under the most extreme conditions investigated.
    Additional Material: 4 Ill.
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  • 17
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 89-95 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Samples of pulverised fuel ash (PFA) obtained both from power stations and from laboratory combustion experiments have been examined by SIMS (secondary ion mass spectrometry) and XPS (x-ray photo-electron spectroscopy).The elemental analysis is at present semi-quantitative and indicates presence of sulphur mainly as sulphate ion in the outer surface layer (5-10 nm) of some samples. Other elements, notably Mg, Fe, K and Ti appear at higher concentrations, up to ∼ 10% once the outer 10-20 nm surface layers have been removed by ion etching.
    Additional Material: 15 Ill.
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  • 18
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 81-88 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The modelless (ML) and micropore (MP) methods for the pore structure analysis of porous particles have been studied. Concerning the ML method, it has been shown that the Kiselev equation can only be used to describe condensation and evaporation in capillaries, but cannot be used to describe the increase and decrease of the thickness of the adsorption layer. Strictly speaking, therefore, the ML method is not modelless even for the pore core size distribution. A comparison between the ML method and methods using an equivalent pore model is given. The results of using the ML method in conjunction with a certain pore model are little less accurate than those obtained by adopting the equivalent pore model straightaway. The parameters required for the calculation of both the pore core size and the pore size distribution as well as the conversion between these two calculations are given.Concerning the MP method, it has been shown that the three types of v-t curves, the theoretical foundation of the MP method, are not in one to one correspondance to the three kinds of adsorption mechanism. From the viewpoint of accuracy, the MP method has no advantage over the methods which are based on the condensation mechanism, both have their own merits.
    Additional Material: 6 Ill.
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  • 19
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 111-116 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The performance of a Po-210 radioactive ionizer for aerosol charge neutralization and bipolar charging has been evaluated. Monodisperse neutral and singly charged aerosols have been passed through the ionizer and their approach to the steady-state Boltzmann charge measured by measuring the fraction of particles that are electrically charged. The result shows that an Nt of approximately 2.5 × 105 cm-3 s is needed for the development of a steady-state charge fraction equal to that given by the Boltzmann' s law where N is the ion concentration and t is the residence time of the aerosol in the neutralizer. In addition, the performance of the ionizer for particle charge neutralization in a vibrating-orifice aerosol generator has been evaluated and the result shows that the source is less effective for this application and the residual charge on the particles is considerably higher than that given by the Boltzmann's law.
    Additional Material: 11 Ill.
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  • 20
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 142-143 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 21
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986) 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 22
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 32-39 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Within grinding machines the load acting on the particles and the loading rate are widely distributed. According to studies on the breakage mechanism of brittle materials, the mechanical properties which relate to breakage vary with the loading rate. In order to elucidate the grinding mechanism within the grinding machines, it is necessary to obtain the relationships between these properties and loading rate.In this study, the variation of strength, fracture energy, new surface area produced by fracture and fracture energy with the loading rate (ranging from 10-1 to 109 N/s) was investigated by means of compression tests on a large number of spherical specimens. As a result, a singularity of crushing behavior was observed under an impact loading corresponding to a duration of time of loading the same as the natural period of the spherical specimen. The crushing efficiency is especially at its maximum.
    Additional Material: 8 Ill.
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  • 23
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 26-31 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Particle size enlargement operations often involve the use of a liquid to improve powder cohesiveness. Capillary suction and surface tension forces acting through liquid menisci between particles are the primary source of the cohesive bonding. The strength of these forces, and consequently the strength of the wet agglomerate, is dependent upon the total liquid content, its distribution within the agglomerate, and the powder wettability (characterized by the liquid surface tension and powder/liquid contact angle).The tensile strength of powder compacts containing submicron carbon black particles has been measured as a function of saturation level for several liquids. It is found that the compact strength increases with increasing surface tension for liquids that exhibit a zero contact angle. Above the critical surface tension for wetting a more complicated situation exists where both the surface tension and contact angle are important.
    Additional Material: 7 Ill.
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  • 24
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    Particle and Particle Systems Characterization 3 (1986), S. 45-55 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The electric resistance pulse or electric sens Xing zone method, primarily invented by W. H. Coulter, is well suited for volume measurements of biological cells and other particles.This review summarizes the methodological investigations at the Max-Planck-Institut für Biochemie into the Coulter method, particularly for measuring biological cells.The distribution of the electric field in Coulter orifices was measured in enlarged model orifices and, additionally, calculated by computer programs. It is shown that the local resistance pulse height depends on the square of the local electrical field-strength and that the particle path in the orifice influences the measured pulse heights and the orientation and deformation of particles.A new transducer system is explained which uses hydrodynamic focusing and allows short time kinetic measurements. It is equipped with a calibrator system which serves also as general control unit.
    Additional Material: 16 Ill.
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  • 25
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 117-121 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper describes an experimental investigation of the charge acquired by a single polymer particle when striking a plate. The particle was projected from a pneumatic gun with variable velocity and angle of impact. The deflected particle was then captured in a Faraday cup and the net acquired charge so measured. The measurements of charge are related, particularly, to the initial potential of the surfaces and to their work functions.
    Additional Material: 9 Ill.
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  • 26
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986) 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
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  • 27
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The determination of the particle size distribution of a powder may last up to 14 hours with standard sedimentation techniques such as an Andreasen pipette.If, in a photosedimentometer, not only the one sensor close to the bottom is incorporated but a number of sensors positioned at different heights, the time required for determining the particle size distribution of a powder may be reduced to 15 minutes. For each sensor there is an optimum location, which is determined both by the distance from the surface to the lowest and the highest sensor and by the number of sensors.The instrument, equipped with three measuring sensors and a reference sensor is connected to a personal computer. The measured particle size distributions are reproducable with a standard deviation of less than 2%. Agreement with a Sedigraph or a sedimentation balance is about the same as the agreement of these two instruments with each other.The time required for the determination of a particle size distribution of a quartz powder suspended in water with particle diameters from 1.5 to 60 μ is 15 minutes.
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  • 28
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    Particle and Particle Systems Characterization 3 (1986), S. 179-186 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Particle size and aspect ratio are amongst the most important parameters which determine the application properties of pigments, fillers and powders for ceramics. A statistical characterization of the samples is therefore needed. In this paper we discuss the measurement of bivariate size distributions of organic pigments and describe a correction procedure for particles with interchanged crystallographic axes. During the crystallization of a pigment, the larger aspect ratios usually result from faster growth rates.
    Additional Material: 4 Ill.
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  • 29
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    Particle and Particle Systems Characterization 3 (1986), S. 8-13 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Cascade impactors are still the most suitable devices with which to measure fine droplet mists in gas ducts. This report describes the measurement technique and underlying principles. It is based largely on experience gained with a type of impactor that has been specially developed for droplet measurements, and also on applications of impactors in the chemical industry. Most of the measurement work has been undertaken in connection with environmental protection. The cascade impactor gives the mass-related droplet size distributions and concentrations within a range extending from about 0.2 to 10 microns. Larger droplets are collected quantitatively in the sampling probe, which serves as a precollector.
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  • 30
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    Particle and Particle Systems Characterization 3 (1986), S. 40-42 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two types of asbestos fiber, chrysotile and amosite, form filter cakes of different permeabilities while having a similar degree of dispersion.The filter cake resistance depends on the disperse phase characteristics and the conditions of cake formation. The main reason for the effects mentioned is different particle flexibility influenced by the specific structure of each type of asbestos particle.The flexible chrysotile fibers in the cake form dense and rigid, amosite, porous deposits. An increase in the velocity of the suspended chrysotile particles, caused by pressure difference and agitation, results in significant differences in filter cake resistance.
    Additional Material: 3 Ill.
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  • 31
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
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  • 32
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 74-80 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Particle penetrations through commercially available, electrically charged fibrous filters have been measured. The particles were monodisperse and in charge equilibrium. Tests were conducted for several particle sizes in the range 0.02 μm ≤ x ≤ 1 μm. The face velocity was varied in the range of 2 cm/s to 30 cm/s. The penetration has a bimodal dependence on particle size. This behaviour is not found for uncharged filters. The reduction in penetration and bimodal dependence is attributed to electrical collection effects. As the face velocity is increased, the electrostatic collection effects are significantly reduced. The results agree quantitatively with a model for particle penetration through charged fibrous filters recently presented in the literature by the authors.
    Additional Material: 8 Ill.
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  • 33
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 122-128 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mathematical treatments used in the evaluation of particle size distribution from pipet-withdrawal centrifuge data are reviewed. An error in the published procedure for multiple-sample withdrawal systems is pointed out and a corrected formulation is presented. An alternative treatment, based on a piece-wise linearization of the size distribution is described. Computer simulations of the analytical and data evaluation procedures indicate that the errors in the original formulation are not generally serious and that the corrected and alternative procedures lead to very similar estimates. Except for some cases involving very narrow size distributions, the alternative approach appears to give slightly closer estimates of the size distribution. Comparisons based on actual experimental data are also described.
    Additional Material: 1 Ill.
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  • 34
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    Particle and Particle Systems Characterization 3 (1986), S. 104-110 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A procedure for estimating the effectiveness of algorithms which retrieve size distribution parameters from cumulative fractions or moments is described. The principle of the algorithm is to select moments, or cumulative fractions, which minimize the condition number. Extensive tests of the algorithm for a distribution consisting of the sum of two log normal distributions were carried out. This procedure can be easily extended to use different numbers and types of constituent functions. The simulations indicated that moment methods which include positive and negative moments give the best result. When the means of the constituent distribution are close, the large condition numbers indicate that no algorithm will give unambiguous values for the parameters.
    Additional Material: 10 Ill.
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  • 35
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 163-167 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Knowledge of the granulometric behaviour of dispersed systems is vital for a full and complete characterisation. Despite the variety of methods and devices which have been developed for this purpose, difficulties frequently arise in the practical determination of particle size distribution. In this paper it is shown, by means of examples, how measurements for surface modified and porous particles can be influenced by the behaviour of the material, and which approaches exist to obtain accurate values by taking this into account.
    Additional Material: 7 Ill.
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  • 36
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    Particle and Particle Systems Characterization 3 (1986), S. 174-178 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper reviews the development of a new annular shear cell for the characterisation of aerated powders. The cell enables the measurement of the transmitted shear stress at degrees of aeration below fluidisation. Results are presented for three powders, Alumina, Phosphate Rock and Sodium Carbonate. These show a large reduction in shear stress for small quantities of air entrainment and a transition from normal coulomb-solid flow to liquid-type flow at high shear rates. This characterisation enables an explanation of the flooding phenomena experienced in powder handling processes.
    Additional Material: 11 Ill.
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  • 37
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    Particle and Particle Systems Characterization 3 (1986), S. 144-144 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
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  • 38
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 3 (1986), S. 151-157 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The commercial forward light scattering equipment, Malvern analyser was used to determine the size distribution of two crystalline powders in the micron range dispersed in aqueous suspensions. The powders used represent two different forms of a micro-porous crystalline adsorbent, silicalite [1]. Previous work by the authors [2], has established the partially absorbing nature of the silicalite crystals at visible wavelengths of the incident light. The theoretical analysis indicates that it is possible to obtain quite accurate size distributions in the (1-10 μm) size range providing measured values of the relative refractive index and the coefficient of absorptivity of the particles are used in the calculations. The present work illustrates the consistency with which the light scattering equipment can respond to changes in the measured size distributions as a function of a number of process parameters such as the solids loading in suspension, the period of agitation, and the intensity of agitation.
    Additional Material: 6 Ill.
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  • 39
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Now fifteen years ago, Small and co-workers [1, 2], introduced Hydrodynamic Chromatography (HDC) as a simple method for the sizing of submicron particles. The particles are fractionated when flowing through a packed column of uniform impermeable beads and emerge in order of decreasing diameter. Noel et al. [4] and Mullins and Orr [3] reported a variant of the technique using a long open capillary tube which has been called Capillary Hydrodynamic Chromatography (CHDC).Recently Brough et al. [5] were able to expand the size range of CHDC down to particle diameters of 0.07 μm and showed that the technique is also able to achieve fractionation in organic solvents.In an attempt to obtain the same particle size analysis range with CHDC as with the recently commercialised HDC (Micromeritics), we investigated the CHDC performance in very small capillaries (0.1 and 0.15 mm). The emphasis of the study has been led on the nature and the concentration of the eluent composition. Indeed an effective reduction in capillary diameter can be obtained if one uses a commercial block copolymer as eluent material. Adsorption of the block copolymer both on the capillary wall and the particles gives rise to a sterical barrier which reduces further the effective capillary diameter and enhances the resolution of the column towards smaller particle sizes.In our view CHDC represents more possibilities in analysing real particle systems, i. e. dispersions with relatively high polymer or polyelectrolyte concentrations. For such systems classical HDC results mostly in the clogging of the column. A series of dispersions and emulsions in concentrated gelatine have been analysed and the P. S. are compared with the results obtained by LCS.
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  • 40
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986) 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 41
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 1-6 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxidative cyclization of D-galactose (p-chlorophenyl)thiosemicarbazone gave 2-(p-chloroanilino)-5-(D-galacto-1,2,3,4,5-pentahydroxypentyl)-1,3,4-thiadiazole (1), whose acetylation afforded 2-[N-acetyl-N-(p-chlorophenyl)]-amino-5-(D-galacto-1,2,3,4,5-pentacetoxypentyl)- 1,3,4-thiadiazole (3). Its periodate oxidation of the glycol groups gave 2-(p-chloroanilino)-1,3,4-thiadiazole-5-carboxaldehyde (4), which can be transformed into 1,2-[2-(p-chloroanilino)-1,3,4-thiadiazol-5-yl]-1-hydroxy-2-oxoethane. A number of hydrazones of the formyl thiadiazole was prepared and its reduction with sodium borohydride gave 2-(p-chloroanilino)-5-hydroxymethyl-1,3,4-thiadiazole (6), whose acetylation gave a mono-O-acetyl derivative (7). Oxidation of the formyl thiadiazole gave 2-(p-chloroanilino)-1,3,4-thiadiazole (9). The spectral data of the compounds were discussed.
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  • 42
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 7-20 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electrochemical Reductive Alkylation of Azomethines with 1-Bromadamantane and 9-Bromo-tetrahydro-exo-dicyclopentadieneElectrochemically generated radical anions of Schiffbases 1a - 11 react in DMF and in the presence of bridgeheadhalogenides as 1-bromoadamantane and 9-bromo-tetrahydro-exo-dicyclopentadiene to 1-[α-(aryl- or alkylamino)-α-arylmethyl]-adamantanes and the correspondent 9-tetrahydro-exo-dicyclopentadienes. In the course of SET-mechanism originating bridgehead radicals couple with the azomethine-radicalanions at the position of the highest unpaired electron density, which is predominantly the carbon of the C,N-double bond. Only in cases when this density at the N-atom is relatively high, or steric hindrance impedes C-alkylation, N-hydroalkylated products as N,N-disubstituted 1-aminoadamantanes and 9-amino-tetrahydro-exo-dicyclopentadienes are formed. Product distribution, cyclic-voltammetric results and quantumchemical data are discussed in terms of mechanism.
    Additional Material: 3 Ill.
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  • 43
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 120-126 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several model thioacrylamides, Me2N—CH = C(R)—C(S)—NMe2 (R = H, Ph  -  2a, b) and (p)MeO—C6H4—NH—CH=C(R)—C(S)—NMe2 (R = H, Ph  -  3a, b) have been synthesized. The 1H-n.m.r. spectra have been taken for discussing the E/Z-isomerism of the thioacrylamides and the assignment further strengthened by an added LIS-study. The 2-unsubstituted compounds have been found to exist exclusively in preferred configurations/conformations: 2a  -  E(s-cis); 3a  -  Z(s-cis); the 2-phenylsubstituted analogs are of divergent behaviour: in 2b the C(S)—NMe2 moiety is found to be twisted out of the common plane, and 3b prefers the flat s-trans conformations (E(s-trans) ⇌ Z(s-trans)). The compounds show restricted rotations about C1, N- and C3, N-partial double bonds. The corresponding rotational barriers, determined as ΔGc#-values by dynamic n.m.r. spectroscopy, are discussed with respect to (i) the resonance branch at C1, (ii) the influence of substituents, and (iii) the effect of steric hindrance in the thioacrylamide moiety generally.
    Additional Material: 2 Ill.
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  • 44
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 137-141 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Syntheses of Heterocycles by Means of Sulfur-Halogen Compounds: A New Synthesis of 2, 3-Dihydrobenzo-1, 4-dioxins
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  • 45
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 142-148 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Quantitative Determination of Some Different Condensation Products of Aniline and Formaldehyd by Different Chromatographic Methods
    Additional Material: 3 Ill.
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  • 46
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 156-162 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Interpretation of Relative Binding Constants of Complexes with Lanthanide N.M.R. Shift ReagentsThe determination of relative complex binding constants of lanthanide n.m.r. shift reagents (LSR) with organic molecules are based on the assumption that in all cases 1:1 complexes exist. A new interpretation of relative binding constants is given which is applicable also to 1:2 complexes. The new defined constant K* describes the relative tendency of the substrate under consideration to form LSR complexes.Using this method it is shown that Eu(fod)3 and Pr(fod)3 form other complexes than that of the 1 : 1 type.The K* of benzaldehyde-LSR complexes correlate linearly with the Hammett substituent parameters.The occurrence of other than 1:1 associates in the complex formation of para-substituted benzaldehydes with Eu(fod)3 and Pr(fod)3, respectively, could be shown; so we used the new model for these systems. The lg K* of the benzaldehydes in its reaction with the mentioned LSR, as well as with Eu(dpm)3, correlate linearly to the Hammett parameter of the para-substituents.
    Additional Material: 3 Ill.
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  • 47
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 190-198 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigations Concerning Sensitization of Silver Free Information Recording Materials with Azo Dyes and Polyhalogen CompoundsRecording materials mentioned in the title are sensitive to the visible region of light. The reason therefore is an energy transfer from the azo dye to the polyhalogen compounds, preferentially CBr4. It's possible to separate the absorption spectra of azo compounds used in this work into two gaussian functions, which relates to n,π*- and π,π*-transitions. Only the excitation of the n,π*-transition causes sensitization. A mechanisms of sensitization is proposed.
    Additional Material: 5 Ill.
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  • 48
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 199-204 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Structure of New Systems of ThiatriazinesDepending on the nucleophilicity of exocyclic nitrogen in 2-guanidino-benzimidazole-1-carbimidic esters and 1-carbamides cyclization with N-sulfinyl amines leads to new 3-amino-1λ4, 2,4,6-thiatriazino[2,3-a]benzimidazole-1-oxide-5-carbimidic esters (3), 1-oxide-5-carbamides (5) and 3-(4-chlorphenylamino)-1-toluene-sulfonylimino-1λ4,2,4,6-thiatriazino[2,3-a]benzimidazole-5-carbimidic ester (7).
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  • 49
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 295-300 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 7 Tab.
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  • 50
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 301-304 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two-dimensional Off-resonance Multiplet Resolved 13C FT NMR Spectroscopy
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  • 51
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986) 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 52
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 567-572 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrylium Compounds. 33. 2-Dialkylamino-2H-thiopyrans from 2,4,6-Triaryl-thiopyrylium Salts2,4,6-Triaryl-thiopyrylium salts 7 react with dialkylamines in diethyl ether to give stable crystalline 2-dialkylamino-2H-thiopyrans 8, the structure of which is in accordance with their u.v., n.m.r. and mass spectra. The chemical properties of 8 parallel those of structurally analogous 2-alkoxy- and 2-dialkylamino-2H-pyrans and 2-alkoxy-2H-thiopyrans. Thus, on heating 2-dimethylamino-2,4,6-triphenyl-2H-thiopyran (8a) with methanol the corresponding 2-methoxy-2H-thiopyran 9 is formed. Nitromethane and ethyl cyanoacetate give rise to ring transformations yielding 1,3,5-triphenyl benzene (10) and 2,4,6-benzonitrile (11), respectively. From 8a electrophiles (e.g. mineral acids, methyl iodide, benzoyl chloride) regenerate the initial thiopyrylium system by taking over the dialkylamino group.
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  • 53
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 597-602 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Spin Trapping. III. Studies of Radical Reactions of a Bicyclic 1-Hydroxy-3-imidazoline-3-oxideRadical addition reactions to the nitrono group and the oxidation of the 8-hydroxy-1,4,5,7-tetramethyl-6,8-diazabicyclo[3.2.1]oct-6-en-6-oxide 2b were investigated by e.s.r.-spectroscopy. Oxidation of 2b by Ag2O, PbO2, hydrogenperoxide, tert.-butoxy and benzoyloxy radicals, respectively, yields a bicyclic nitroxide with typical a(N)-value (1,9 mT). Testing a wide range of carbon-centered radicals we did not find, however, any spin adducts in contrast to the literature. Only H-atoms are found to add to the nitrone function of 2b giving a bicyclic nitroxide 4b (R′ = H) with a(N)-value of 1,4 mT, a(Hax) = 2,4 mT. The relationship between a ring-chain tautomerism of 2 as previously described and the formation of radicals has been demonstrated by radical reactions of derivatives of ring opened isomers 5b.
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  • 54
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 621-626 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermolysis of Aryldiazonium Salts in Polymer Matrix. III. Coloured Dialkylamino-benzenediazonium Salts
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  • 55
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 640-642 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C-N.M.R. Chemical Shifts of 2-Methylthio- and 2-Ethylthio-1, 3-dithiolium-iodide and -tetrafluoroborate
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  • 56
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 651-655 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Phosphorus Compounds. XV. Studies on the Reactivity of Selected Vinyl Phosphates
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  • 57
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 648-650 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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  • 58
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 784-796 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular geometries in the electronic states S0 and T1, heats of formation, singlet-triplet splitting and transition energies of cumulenes and 1- and 2-aza-cumulenium cations up to chain lengths of 11 C-atoms have been investigated by means of MINDO/3, CNDO/S and a modified PPP procedure. As far as experimental data are available their agreement with the theoretical results is satisfactory. This enables the molecular structure, the spectral behaviour and the colour of cumulated chains to be extrapolated up to chains of 20 C-atoms. The properties of the cumulenes studied are compared with those of polyenes and polymethines and attempts were made to integrate cumulated chains within these classes of unsaturated chain molecules.
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  • 59
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 829-840 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Increment System for Predicting of the Position of Ion Pair Charge-Transfer Bands in Water and Non-aqueous SolventsThe energy of the absorption maximum of ion-pair charge-transfer bands, ΔGCT, occuring in addition to the absorptions of the single ions, is approximately the sum of contributions (increments) of the ions concerned. On the basis of spectroscopic data, an increment system for predicting of ΔGCT in aqueous solution has been proposed. A linear relationship between the increments and the standard electrode potentials of ions has been found, permitting the expansion of the increment system. The difference between calculated and experimental values does not exceed 2500 cm-1. The applicability of the increment system to non-aqueous solvents has been proved in several cases.
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  • 60
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    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 841-848 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the hydrolysis of some substituted benzylidene benzoichydrazide 1a-e in 40% (v/v) ethanol buffer mixture have been investigated by differential pulse polarography. The mechanism of the hydrolysis in acidic buffer solutions is discussed.The catalysis by H⊕ involves the conversion of the hydrazide compound to its conjugated acid in a rapid preequilibrium step followed by a slow attack of water. The effects of pH, water, organic solvents and molecular structure on the reaction rate and the activation are investigated.
    Additional Material: 4 Ill.
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  • 61
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 331-334 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3-Oxo-2,3,5,6,7,8-hexahydro-s-triazolo[4,3-a]pyrimidine (5) was synthesized and its reactivity towards acylating reagents was examined. The assignment of tautomeric structures based on n.m.r. spectral data is discussed.
    Additional Material: 1 Tab.
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  • 62
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 359-372 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pyrylium Compounds. 31. Reaction of 3-Alkyl-2,4,6-triarylpyrylium Salts with 1,3-Diketonates: A Method for the Preparation of 3-Acylsubstituted BenzophenonesReaction of 3-alkyl-2,4,6-triarylpyrylium salts with 1,3-diketones in the presence of one equivalent of triethylamine or potassium tert-butoxide does not lead  -  as originally suspected  -  to the primary adducts of 2H-pyran structure 6, but to the open-chain valence isomers 7. Treatment of the latter with one equivalent of tert-butoxide in tert-butyl alcohol gives the same 3-alkyl-2,4,6-triarylacetophenones 9 which are obtained directly from 5, 1,3-diketones and two equivalents of potassium tert-butoxide. However, on treating 7 with aqueous ethanolic sodium hydroxide 3-acylsubstituted benzophenones 10 are formed in good yields. The reaction sequence 5→7→10 can also be performed through a one-pot-procedure.  -  The i.r., u.v., n.m.r. and mass spectroscopic data of the novel products 7, 9, and 10 are reported.
    Notes: No abstract.
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  • 63
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 545-545 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 64
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 741-749 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Chemistry of 5-Amino-2-phenyl-1,2,3-thiadiazolium SaltsTreatment of the title compounds 1 with pyridine yield the phenylhydrazones of the 1,2,4-thiadiazol-3,5-diyl-glyoxylic acid derivatives 4. The amides 4a, b can also be obtained by reaction of the phenylhydrazono cyanacetoamides 3a, b with sulphur in the presence of pyridine. Nitriles react with 1 to form the phenylhydrazones of the 1,2,4-thiadiazol-5-yl-glyoxylic acid derivatives 6. Reduction of 6a yields the 1,2,4-thiadiazol-5-yl-glycine derivative 7. Depending on its condition the reaction of 1c with benzoyl acetonitrile yield either the 1,2,4-thiadiazole or the 4-amino-thiazole derivative (6i or 8). From 1a and ethyl acetoacetate the phenylhydrazone of the thiazol-2-yl-glyoxylic acid derivative 9 arises which can be reduced to yield the thiazol-2-yl-glycine derivative 10. The addition of 1 onto isothiocyanates in the presence of pyridine yields the substituted N-(1,2,3-thiadiazol-5-ylidene)-thioureas 12a, b. Carboxylic acids react with 1 in the presence of pyridine to form the 5-Acylimino-1,2,3-Δ3-thiadiazolines 13.
    Additional Material: 1 Tab.
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  • 65
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Interaction of Donors with Alkylaluminium Halogenides. III. Model Calculations with the CNDO/2-MethodThe quantum chemical model calculations show, that the Lewis acidity of the compounds (CH3)nAlCl3-n (n = 0…3) decreases with increasing n. The influence of the methyl ligands seems to be additive.The heterolysis of the R—X bond (R = H, CH3; X = Cl, OH, NH2, CH3) is promoted by the cooperation of the Lewis acids (CH3)nAlCl3-n. Fox X = OH, NH2, CH3 the energy effort is nearly the same, while it is smaller by a third for X = Cl. Before heterolysis the formation of a complex takes place between the Lewis acid and the donor R—X. The complex with HCl is more stable than that with NH3.
    Additional Material: 3 Tab.
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  • 66
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 911-920 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Tab.
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  • 67
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 932-936 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 68
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 937-940 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigations of the Photofading of Tautomeric Azo Dyes. VII. Quantumchemical Calculations for the Fading Behaviour of Hydrazones
    Additional Material: 1 Ill.
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  • 69
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    Topics: Chemistry and Pharmacology
    Notes: Syntheses of C-Nucleosides and Analogs of C-Nucleosides. IV. Preparation and Characterization of 5(S)- and 5(R)-Tetrahydroxybutyl-3-methyl-1,3-oxazolidines1-Deoxy-1-methylamino-D-hexitols 1,2,3 react with ketendithioacetals 4 to give the acyclic C-nucleosides 5,6 and 7. The structure of the compounds were verified by means of periodate oxidation and spectroscopic investigations. Some properties of the acyclic C-nucleosides were investigated by acetalation reactions on the tetrahydroxybutyl chain.
    Additional Material: 2 Tab.
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  • 70
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 42-54 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stereochemistry of the 2-Aryl-cyclohexanones. I. Analysis of the Configuration and Conformation of the cis-trans-Isomeric 2,6-Dimethyl-2-aryl-cyclohexan-1-ones by the Aid of their OximesDesulfurization of the n-butylthiomethylene ketone 6 with Raney nickel yields a mixture of trans- and cis-stereoisomers 7 and 8, the conformations of which are 7A and 8B, respectively. While the ketone 7 gives rapidly and quantitatively the oxime 9, the isomer 8 reacts much more slowly to a mixture of 9 and 10. A detailed analysis of the configuration and conformation of the ketones 7 and 8 as well as the oximes 9 and 10 is given.
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  • 71
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 97-104 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Assignment of the Vibrational Spectra of Organic Molecules by MNDO CalculationsWavenumbers and intensities of the molecular vibrations can be calculated by the semi-empirical SCF-MO method, MNDO. The calculated normal coordinates show the displacements of the atoms in the course of the vibration and provide the assignment of mode and symmetry of the vibrations. This will be shown for the following examples: acetylene, ethylene, substituted and deuterated ethylenes, acetonitrile as well as for EDA complexes. We found a good qualitative agreement between calculated and experimentally observed IR-data.
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  • 72
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 113-119 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Studies on UV/VIS Absorption Spectra of Azo Dyes. XV. An Analysis of the Absorption Spectra of 4,4′-DiaminoazobenzenesIn the visible absorption spectrum 4,4′-bis-diethylaminoazobenzene shows two absorption maxima (λmax = 426 nm and λmax = 477 nm) with high intensity. Quantum chemical calculations and examination by peak separation of six 4-substituted azobenzenes and six 4′-substituted 4-diethylaminoazobenzenes (1a-k) indicate that the longest wavelength band is due to a n-π* transition and the other band is due to a π-π*-transition.This is verified using an increment system for n-π* absorption maxima. A linear relation is found between intensity ratios of the two bands and the HAMMETT-σ-constants of the substituents. With increasing electron releasing tendency of the substituents the absorption intensity of the n-π*-band increases.
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  • 73
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 222-230 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Radical Reactions of N-Heterocyclic Compounds. V. ESR-Investigation of Nitroxide Radicals of Substituted 3-Anilino-1,5-diphenyl-pyrazolesThe correlation of the e.s.r. splitting constants with the Hammett values for nitroxides from substituted 3-anilino-1,5-diphenylpyrazoles 1a-e and substituted 1,5-diphenyl-3-p-toluidino-pyrazoles 1f-i provides evidence for extensive interannular conjugation between the N1-benzene ring and the pyrazole ring of these nitroxides. The conjugation between the arylamino group and the pyrazole ring is extensive only in the nitroxides derived from 1f-i. The captodative substituted p-toluidino-nitroxides 2g, h have a better spin distribution than the nitroxide 2i with two electron-donating substituents.
    Additional Material: 6 Ill.
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  • 74
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 245-252 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Starting from 1-(methylthiocarbonylmethyl)pyridinium iodide 1, several attemps were made to prepare 4,6-diaryl-2-pyridothiones. Synthesis of thioamides 2-10 was produced easily and with high yield, but thioamide behaves as a bad stabylising group. A modified method using a mixture of 1, compounds of the type R—NH2 and the corresponding chalcone, produced 2-pyridothiones only when R=H, and the compounds where isolated in the oxidised dithioform.Other reactions gave pyridinium salts, or 1,2-azoles, with no intervention of 1 in the process.
    Additional Material: 5 Ill.
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  • 75
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 275-283 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Recoupling of 4-Arylazo-2-pyrazoline-5-ones with p-Quinonediimine Cations4-Arylazo-2-pyrazoline-5-ones (1a-j) readily undergo coupling reaction with p-quinonediimine cations (2a, b) to form azomethin dyes (3a, b). The dependence of the rate constants kK of the dye formation on the substituents of 1a-j as well as on the ionic strength show that the rate-determining step of the coupling reaction is the formation of the intermediate 4 in a bimolecular reaction between the carbanions of 1a-j and p-quinonediimine (2a, b).It became evident that the benzenediazoniumion (5a-j) is eliminated in the reaction of 4 to 3a, b. Under the coupling conditions used, substituted benzene is formed in the reduction reaction of 5a, b by the p-phenylendiamine (7a, b) or by the leuco dye (6a, b).
    Additional Material: 6 Ill.
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  • 76
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 285-290 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Tab.
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  • 77
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 380-388 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: About the Reaction of 5,6-Dihydro-1,4-oxathiin-4,4-dioxides with Nucleophilic CompoundsBy reactions of 5,6-dihydro-1,4-oxathiin-4,4-dioxides (1, 5, 8) with thioles, amines and CH-acid compounds 2-substituted ethansulfonylcarbonyl compounds are formed. The structures of the reaction products are determined by elemental analysis, i.r. and 1H-n.m.r.-spectroscopy.5,6-Dihydro-1,4-oxathiin-4,4-dioxide sind gut zugänglich durch die Oxidation von 5,6-Dihydro-1,4-oxathiinen mit Wasserstoffperoxid. Besonders zur Darstellung der 5,6-Dihydro-2-methyl-3-carboxamido-1,4-oxathiin-4,4-dioxide, von denen einige im Pflanzenschutz wegen ihrer systemischen fungiziden Wirkung Bedeutung erlangten, wurden verschiedene Methoden beschrieben [1, 2]. In ähnlicher Weise lassen sich auch die entsprechenden Ester und Säuren synthetisieren.
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  • 78
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 401-406 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-(N-Cyclohexyl)aminopyridine 1 was reported to form a 1,2-dihydropyridine derivative with carbonyl chloride [4]. This implies that the pyridine nitrogen of 1 is a stronger nucleophile than the exocyclic nitrogen. Presently 1 is found to react with electrophiles, including carbonyl chloride, to form derivatives at the exocyclic nitrogen of 1. This is proven by relating the structures of these compounds to 2-(N-alkoxycarbonyl-N-cyclohexyl)aminopyridine 1-oxides 5. Compounds 5 were prepared by two independent routes, thus proving the structure of 5. 1H n.m.r. and 13C n.m.r. spectra also support the assigned structures.
    Additional Material: 1 Tab.
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  • 79
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 419-429 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,4-Benzoquinones and 1,4-naphthoquinones carrying 3′,3′-dimethyloxiranyl, dimethylacetyl or oxiranylmethyloxy substituents (1, 2 or 3) have been synthesized. The methods presented involved epoxidation of a sterically overcrowded double bond as a crucial step for synthesis of (3′,3′-dimethyloxiranyl)quinones 1. Reaction of aryllithium derivatives with 2-chloro-2-methyl-propanol unexpectedly led to (dimethyl)acetylarenes 11 subsequently oxidized to (dimethylacetyl)-quinones 2. High cytotoxicity of 1 against KB cells has been revealed contrary to significantly lower activity of 2 and 3. The structure-activity relationship was discussed in terms of current theory of biologically activated alkylating agents.
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  • 80
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By computer simulation of the dependencies of the mole numbers of the ketones and alcohols derived from the starting paraffin, of the acids and esters, and in some cases also of the lower alkan-2-ones on the paraffin conversion relative rate constants were determined on the basis of a plausible kinetic model of the paraffin oxidation. The data obtained show that about 67% of the oxidation proceeds via bifunctional primary products. With the aid of the relative rate constants determined a good simulation of the experimental mole number-conversion curves is possible.
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  • 81
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 515-521 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: About the Reactions of Benzimidazole-2-carbohydrazide with Electrophilic CompoundsBenzimidazole-2-carbohydrazide (1) reacts with aldehydes and ketones to form N-alkylidene-benzimidazole-2-carbohydrazides(2a-j). With carbon disulfide, diphenyl carbonate and cyanates, ring closure takes place to afford 1,2,4-triazines and 1,3,4-oxadiazoles. Attempts to synthezise 2-isocyanato-benzimidazole failed.1H-n.m.r. and 13C-n.m.r. spectroscopic data of the compounds are given.
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 539-545 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electrochemical Carboxylation of Substituted Vinyl Ketonesα-Chlor-β-acyl-vinylsulphides (1a-f) and keten-S, N-acetales (3a,b) are reduced in the presence of CO2 at the cathode to yield the corresponding acids (4a-f resp. 5). Whereas the carboxylation of 1 proceeds via elimination-addition mechanism, the reduction of 3 is similar to the keten-S, S-acetales described earlier an EC (addition) EC (elimination) sequence.
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  • 83
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    Topics: Chemistry and Pharmacology
    Notes: Decomposition of cyclohexane and 1-methylcyclohexane hydroperoxides in cis-and trans-1,4-dimethylcyclohexane in the presence of boric acid esters results in a non-stereospecific attack at the tertiary C—H bonds of the 1,4-dimethylcyclohexanes. Mixtures of cis- and trans-1,4-dimethylcyclohexanols are formed in every case. This proves that the attack of the hydroperoxides at the tertiary C—H bonds does not proceed by an aliphatic SE2 mechanism.
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  • 84
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 849-855 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: About the Reaction between n-Alkanes and Aluminium Nitrate-nonahydrateThe reaction between n-alkanes (C10—C13) and aluminium nitrate-nonahydrate in the temperature range 353-403 K, time of contact 12 h and mole ratio nitrating agent: hydrocarbon from 1:2 to 2:1 was investigated.The product obtained was separated on silicagel. The fractions separated by adsorption chromatography were studied by i.r.- and combined GC/MS spectroscopy. Only alkyl nitrates were obtained. The oxidation processes yield aldehydes, ketones and nitrate carboxylic acids.The model reaction with n-undecane shows that undecyl-3-nitrate (5), undecanal (6), undeca-5-on (7) and nitrate undecanic acid (8) are obtained.
    Additional Material: 3 Ill.
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 886-892 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quantum-Chemical Calculations on Allyl-Type Radicals: Methyl-Substituted Allyl RadicalsMethyl-substituted allyl radicals were calculated by MINDO/3. Based on heats of formation of planar and perpendicular radicals phenomena like thermodynamic stability and regio as well as stereoselectivity are discussed. It is shown that the semiempirical method has artefacts. But in most of the cases MINDO/3 gives a qualitatively correct description of the chemical behaviour of allyl radicals with respect to experimental details.
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  • 86
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    Topics: Chemistry and Pharmacology
    Notes: Diels-Alder-Reactions 17-Substituted Estra-1,3,5(10), 16-tetraenes with 1,3-Dienes under High Pressure
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  • 87
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 921-928 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Studies on the Synthesis of Azophenines from o-Benzoquinone Dioxime
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 929-931 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 89-96 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Picosecond Spectroscopic Investigations of 1-Phenylazo-2-naphtholsThe photoisomerization of substituted 1-phenylazo-2-naphthols is studied in fluid solution and in polymer film (cellulose acetate). With the help of picosecond spectroscopy the absorption from an excited state, bleaching, and time resolved fluorescence were measured. The results can be interpreted by the assumption that during periods of less than 10 ps, the S1-state of the azo form is changed to the S1-state of the hydrazone form by proton transfer. This S1-state relaxes by internal conversion and by diabatic isomerization with a time constant of 20 to 60 ps, depending on substituent and solvent. By exciting the substances solved in polymer film, we observed a relatively strong fluorescence, which is found to be amplified spontaneous emission (superfluorescence).
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    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 393-400 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Unambiguous preparations of 2-(N-alkoxycarbonyl-N-phenyl)aminopyridine 1-oxides are used to prove that the product from 2-phenylaminopyridine 3 and phenyl isocyanate is the expected urea 2a. Recently a 1,2-dihydropyridine derivative 1 [4] has been claimed to be the product from 3 and phenyl isocyanate. The exocyclic nitrogen of 3 invariably reacts as the nucleophile towards electrophiles such as carbonyl chloride, esters of chloromethanoic acid and aryl isocyanates. 1H n.m.r. and 13C n.m.r. spectra support the assigned structures of the products from these ractions.
    Additional Material: 1 Tab.
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  • 91
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    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 413-418 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: CW CO2 laser photosensitized (SF6) pyrolysis of tetralin proceeds mainly via dehydrogenation channel affording 1,2-dihydronaphthalene and naphthalene. Less important ring cleavage products are indene, styrene, ethylbenzene, toluene, and benzene, together with ethylene and methane. No occurrence of polyaromatics and high yields of ethylene compared to methane are the features differing this process from high temperature conventional pyrolysis.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 92
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ozonization of endo-cis-bicyclo[3.3.0]oct-6-en-2-ol (1) in methanol followed by reduction with dimethyl sulfide in the presence of traces of an acid yields in a one-pot procedure an anomeric mixture of 3-exo-methoxy- and 3-endo-methoxy-2-oxabicyclo[3.3.0]octane-6-endo-carbaldehyde (3a and 3b) in a ratio of 9:1. This mixture is converted by base catalyzed epimerization in an overall yield of about 65% into a mixture of the anomeric 6-exo-aldehydes 5a and 5b, a versatile starting material for the synthesis of prostaglandins of the PG2-type.
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  • 93
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 449-453 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bicyclenes. XV. The Influence of Brönsted Acids on Diels Alder Reactions
    Additional Material: 1 Tab.
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  • 94
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 465-468 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 95
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986) 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 96
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mole numbers of the starting paraffins, of the intermediate alcohols and ketones with the same chain lengths, of the lower alkan-2-ones, of the carboxylic acids, and of the esters were determined at different reaction times for the oxidations of n-tridecane, n-tetradecane, and n-pentadecane with molecular oxygen at 140°C in the presence of 0.1% Mn-stearate. In the stationary region of the oxidation about 1.2 moles of acids and 0.7 moles of esters are formed from 1 mole of paraffin consumed. The relative oxidation rates of alcohols and of ketones with reference to the starting paraffins were estimated from the mole numbers of the starting paraffins, the alcohols and the ketones at the maxima of the alcohols and the ketones. These values are higher than those determined by competitive oxidations, and this discrepancy is an indirect evidence of the formation of bifunctional intermediates from the starting paraffins. The relative rates of the formation of alcohols, ketones, and bifunctional products from normal paraffins were estimated.
    Additional Material: 4 Ill.
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  • 97
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    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 497-514 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Spectral Characterization of Blue Azo Dyes of the Benzene Series53 Donor-acceptor substituted azo dyes of the benzene series were prepared by diazonium-coupling reactions (1 a-s) or halogen-cyanide exchange (→2 a-x, 3 a-j). Described are the preparation of the amines 4 a-m and the coupling compounds 5 a-t and the procedure of diazotizing and coupling.The colouristic and spectroscopic data show that compounds of the general formula 1 are excellent brilliant blue azo dyes useful for dyeing polyester material.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 98
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 522-528 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 6-Arylpyridazin-3(2H)-thiones exist mainly, if not entirely, in the thione form (1). This was shown by spectroscopic studies on some of these compounds and their substitution products either on the nitrogen or on the sulphur [in the mercaptopyridazine form (2)]. However, the reacting tautomer of these compounds was found to be dependent upon the basicity of the reaction medium. Selected 6-arylpyridazin-3(2H)-thione derivatives react with formaldehyde and sec-amines to give N-2-aminomethyl derivatives (8) [thione form (1)]. On the other hand oxidation and alkylation reactions gave disulphides (10) and S-alkyl derivatives (7) [mercapto form (2)].
    Additional Material: 1 Tab.
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  • 99
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    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 237-244 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 8H-1,2,4-Triazolo[4,3-a]perimidinesReaction of 2-hydrazinoperimidine (3) with carboxylic acids or its orthoesters leads to 8H-1,2,4-triazolo[4,3-a]perimidines (5a-h). 3 and aldehydes yield the aldehydehydrazones (6b,c,d) which are converted in 5 by air oxidation. The structures of the new compounds were determined by means of i.r., u.v., 1H-n.m.r. and mass spectroscopy.
    Additional Material: 1 Tab.
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  • 100
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 253-260 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Electronic Absorption Spectra of Tetrakis(dialkylamino)phenyl Substituted Nickel DithiolenesNickel dithiobenziles with four dialkylamino groups (1a, b) have been synthesized from the correspondent 4,4′-bis-(dialkylamino)-benzil (2a, b) or 4,4′-bis-(dialkylamino)-benzoin (3b). Such compounds show the lowest transition energy ever observed for any dithiolene complex. The absorption maximum depends strongly on solvent polarity and can be shifted in the range 1000 to 1450 nm.
    Additional Material: 1 Ill.
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