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  • 101
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 261-274 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Disintegration of microorganisms in a continuously working industrial homogenizer has been studied. The homogenizer consists of rotating discs in a cylinder filled with glass beads. Different parameters for disintegration of baker's yeast were investigated. The disintegration process is a first-order reaction and it is influenced by the flow rate of the suspension and by the agitator speed. At a flow rate of 200 liters/hr about 85% of the yeast cells can be disrupted in a single pass through the disintegrator. This type of disintegrator can be used for disruption of cells in order to produce single-cell protein, active enzymes and other valuable cell components.
    Additional Material: 8 Ill.
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  • 102
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 293-293 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
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  • 103
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 104
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 419-422 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 105
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Partially purified lactoses (β-D-galactoside galactohydrolase, EC 3.2.1.23) from Aspergillus niger, Ladobacillus helveticus, and Saccharomyces lactis were immobilized on diazotized porous glass particles (mean pore diameter, 86.5 nm: particle size diameters, 75-125 μm). In acid whey containing 4-4.5% lactose, A. niger lactase gave the highest activity (89 μmoles lactose hydrolyzed/g glass, min) at 55°C and pH 4.5. Glass-immobilized A. niger laclases (lactase-BG) retained much hydrolytic activity after storage and periodic use for 165 days at 55°C. For values of X greater than 30%, hydrolysis of 0.12M lactose in acid whey by a continuous flow column packed with 2 ml of lactase-BG particles could be correlated by X = 17.2(V/F) + 12.5 where X = lactose hydrolysis, percent of lactose originally present; V = volume of packed bed of lactase-BG, ml; F = flow rate of acid whey, ml/min.
    Additional Material: 3 Ill.
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  • 106
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 107
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 423-427 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Tab.
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  • 108
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 41-59 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The growth of a mixed methane-utilizing culture in a continuous flow fermenter has been studied under both methane and oxygen limitation. Small additions of methanol have been shown to inhibit the methane-utilizing moiety in the culture and it has been shown that the Hyphomicrobium sp. in the mixed culture removes any inhibitory methanol. The interaction between the methane-utilizing Pseudomonas sp., and the Hyphomicrobium sp. has been explained and a model of the continuous mixed culture under oxygen limitation has been formulated. Qualitative predictions of transient phenomena by the model have been verified experimentally.
    Additional Material: 8 Ill.
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  • 109
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 135-147 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An α-galactosidase which will hydrolyze the oligosaccharides melibiose, raffinose, and stachyose has been immobilized on nylon microfibrils suitable for use in large flow-through reactors. This catalyst system is stable for many months, both under use and storage conditions. The immobilized enzyme behaves similarly to the enzyme in solution, characteristically exhibiting both product and substrate inhibition. The catalyst is prepared in situ and a large, 8-liter reactor has been made. The catalyst has been used to reduce the raffinose concentration in beet sugar molasses.
    Additional Material: 5 Ill.
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  • 110
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 231-250 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Evolutionary operation (EVOP) was used to experimentally investigate the optimum steady state operating conditions for a step aeration activated sludge waste treatment process. A laboratory scale two tank step aeration activated sludge unit with fixed total volume, total influent flow rate, recycle flow rate, and sludge wasting rate was employed. The volume ratio and flow rate ratio which minimized effluent chemical oxygen demand were determined. The results indicate that EVOP is a useful technique for improving the performance of biological processes.
    Additional Material: 6 Ill.
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  • 111
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 251-260 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of wall growth are described for a mixed methane-utilizing bacterial population growing in both batch and continuous culture. These effects are similar to those predicted previously by a theoretical analysis (Topiwala and Hamer, 1971).
    Additional Material: 5 Ill.
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  • 112
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 279-284 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 7 Ill.
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  • 113
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 285-287 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Tab.
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  • 114
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 275-277 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Tab.
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  • 115
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 289-291 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Tab.
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  • 116
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 333-343 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: One of the main reasons for immobilizing an enzyme is to enable its reuse, or continuous use, in a reactor. Consequently immobilized enzyme stability is an important factor in enzyme reactor design. The performance of the reactor will decrease if during operation the support material disintegrates into smaller particles that pass out of the reactor system.When β-galactosidase is immobilized by covalent attachment to AE-cellulose, the smaller particles have a higher activity. After subjection of the immobilized enxyme to a shear stress the average particle size decreases and the total enzymic activity increases. A loss of small particles from the reactor, although constituting a small weight percent loss of support, will result in a disproportionately large loss in activity. The relevance of these observations to reactor performance is discussed.
    Additional Material: 4 Ill.
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  • 117
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 345-360 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A tubular membrane reactor offers many advantages over a solid wall reactor to carry out an enzyme catalyzed reaction. With proper membrane selectivity, the product, may be separated from the reacting stream and the enzyme recycled for continuous reuse. In most cases, enzyme reuse contributes to the economic feasibility of a continuous enzyme catalyzed process. Furthermore, the efficiency and performance of a membrane reactor is greater than that of a solid wall reactor.Continuous hydrolysis of starch by the enzyme β-amylase, carried out in a commercially available tubular membrane unit, is studied at different starch and enzyme concentrations for a given system pressure and inlet flow rate. Results show that the performance of the membrane reactor is in all cases greater than that of the solid wall reactor. A steady state in performance of permeation rate is, however, not reached by the membrane reactor, which shows a continuous decline within the periods examined in this study. This decline is caused in part by the aging of the starch solution, but mostly by the formation of a concentrated, or gel, layer at the membrane surface. This appears to be the main limiting factor for this process since the decline in reaction and permeation rate results in a severe decrease in the amount of maltose in the permeate.
    Additional Material: 12 Ill.
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  • 118
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 371-383 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The disintegration of baker's yeast (Saccharomyces cerevisiae) by a high pressure homogenizer, to a pressure of 25,000 psi. (172.37 MNm-2) is described, together with details of the methods of measurement used to obtain information on the valve movement and pressure transients. The theory of the mechanism of cell disintegration is discussed.
    Additional Material: 10 Ill.
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  • 119
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 361-369 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Hen's egg white lysozyme (EC 3.2.1.17) has been covalently attached to a polystyrene matrix via interaction of protein nucleophiles with an aromatic imidazolide function under anhydrous conditions. The polymer-enzyme complex is prepared in a way which allows nonaqueous solubilization of the complex. The activity of the bound enzyme compares favorably with the activity of the native protein. The pH optima for the matrix-supported protein are shifted toward the basic side. The effect of substrate concentration on rate has been determined. (A preliminary report of this work has been published: G. J. Bartling, H. D. Brown, S. K. Chattopadhyay, Nature 243, 342-344 (1973).)
    Additional Material: 4 Ill.
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  • 120
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 413-417 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 121
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 385-396 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Trypsin (EC 3.4.4.4) was immobilized in low yield on aminoalkylsilylated magnetite (Fe3O4). Better results were obtained when trypsin was immobilized by crosslinking with glutaraldehyde on magnetite. The preparation contained 36 mg protein/g magnetite and the enzyme retained 46% and 11% of esterase and proteolytic activity. Immobilized trypsin was more heat stable than trypsin. Invertase (β-D-fructofuranoside fructohydrolase, EC 3.2.1.26) was cross-linked on magnetite with glutaraldehyde in low yield due to the inactivation of the enzyme. However in the presence of 1% sucrose, the total activity recovered was 79% of the initial activity and the preparation contained 4.4 mg/g of active invertase. Immobilized invertase was less active than invertase when acting on oligosaccharides of the raffinose family. The immobilized enzymes could be easily recovered, from solutions or suspensions, magnetically.
    Additional Material: 7 Ill.
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  • 122
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 431-454 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A general model of the kinetics of microbial growth has been developed involving the kinetics of incorporation of substrate into biomass and the maintenance energy requirements.Results obtained from batch cultures of the yeast Saccharomyces cerevisiae growing in synthetic media at pH 5.1 and 30°C permitted all biological parameters in the model to be calculated.Values obtained for these parameters were: maximum specific glucose uptake rate (μSm), 2.08 g/g biomass/hr; apparent Michaelis constant for glucose (KS), 0.1 g/liter (5.5 × 10-4M) apparent Michaelis constant for oxygen (KL), 1.4% O2 (3.2 × 10-6 M) quantitative index of the Pasteur effect (b), 4.9 × 10-4%-1 O2 (207 M -1). Under conditions of strongly substrate-repressed respiration the values obtained for YATP and P/O were constant over the course of the exponential phase of growth (YATP = 10.4 g biomass/mole ATP; P/O = 3 moles ATP/atom 0). Mass balances for aerobic and anaerobic cultures confirmed the results obtained form the generalized model. Results presented suggested the operation of a mechanism for regulating energy-yielding metabolism which involved an equilibrium between the systems of oxidative phosphorylation and dephosphorylation and was dependent upon the level of catbolite repression.
    Additional Material: 8 Ill.
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  • 123
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 124
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1025-1044 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies were carried out on the production of Sindbis, influenza and vesicular stomatitis viruses in suspensions of chicken embryo and rat embryo cells. The yield of Sindbis virus in chicken embryo cell suspensions was independent of the multiplicity of infection over the range 0.0001 to 0.01 although reduction in multiplicity caused a delay in virus production. With influenza virus the use of higher multiplicities gave increased virus yields possibly due to the very slow production at low multiplicities. In both monolayer and suspension cultures of chicken embryo cells addition of serum or use of media richer than minimum essential medium (Eagle) had little effect on Sindbis virus production, but if the glucose were omitted the virus yield was markedly reduced. In cell suspensions, a marked reduction in virus yield occurred if infection were delayed more than 24 hr after cell preparation whereas in monolayers the delay of infection allowed cell propagation and hence a higher yield of virus. It was also shown that vesicular stomatitis virus can be produced in chicken embryo cell suspensions, and that rat embryo primary cell suspensions can be used to prepare both Sindbis and vesicular stomatitis viruses. Sindbis virus obtained from chicken embryo cell suspensions was purified by polyethylene glycol precipitation and sucrose density gradient centrifugation and shown to contain only those proteins previously identified as viral, without any contamination from chicken cell proteins. The relative ease and economics of virus production by cell suspension and monolayer methods is compared.
    Additional Material: 4 Ill.
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  • 125
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1081-1093 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Numerical solutions to the equations describing simultaneous mass transfer and enzymic reaction within porous spherical particles have been used to examine the effect of enzyme content and other parameters on the kinetic behavior of immobilized enzymes. These solutions have also been compared with experimental data for enzymes immobilized to DEAE-cellulose particles. The influence of particle size and enzyme content on catalyst design is discussed.
    Additional Material: 6 Ill.
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  • 126
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1123-1133 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Degradation of UNA by endogenous RNase in cell suspensions of Saccharomyces cerevisiae was found to be achieved by mechanical disintegration followed by incubation in the presence of NaCl. The incubation parameters pH, temperature, time, and concentration of NaCl were investigated. Protein concentrates with a low content of RNA were obtained by precipitation of the incubated suspensions and separation of the degradation products.On a pilot plant scale the incubation was performed at 50°C and pH 5.6 in the presence of 3% NaCl for 20 min. Kilogram quantities of protein concentrates containing 1.4% RNA and 8.2% nitrogen were obtained. The RNA reduction and the nitrogen yield was 85 and 60%, respectively. The yield of amino acids was about 75%. The process described can probably be applied for large-scale production.
    Additional Material: 4 Ill.
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  • 127
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1261-1272 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A tubular loop batch fermentor has been designed and constructed, and was found to behave in a similar manner to a conventional stirred tank reactor. It appeared that foaming could be greatly reduced as no air ever encountered the impeller. The fluid mechanics of pipe flow are considerably simpler than tank flow patterns. On this basis a design procedure for a large scale tubular fermentor was outlined, which had considerable advantages over the more complex scale-up problems of a tank fermentor.
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  • 128
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: System response data for step changes in input tracer concentration have been obtained for two different impeller agitated continuous flow mixing systems containing aqueous polysaccharide solutions. The vessel volumes were 1.6 and 10.9 liters. Polysaccharide concentration, dilution rate, and impeller speed were varied according to a plan devised using dimensional analysis and assuming that bulk motion is the predominant mass transport mechanism in the system. The data show that this is not true and that serious errors may occur if scale-up calculations are based on assuming that bulk motion predominates. Under the operating conditions used, perfect mixing was not observed.
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  • 129
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    Biotechnology and Bioengineering 16 (1974), S. 997-1003 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
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  • 130
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    Biotechnology and Bioengineering 16 (1974), S. 1015-1023 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The CO2 mass balance for a suspension of algae cultivated in the region of neutral pH of the suspension on an open cultivation surface with a flowing suspension was assessed. From this balance an analytical expression for the course of free CO2 dissolved in the suspension along the flow of the suspension is obtained. Relations for the rate of CO2 decrease in the suspension and the utilization of CO2 supplied to the cultivation surface are derived.
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  • 131
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    Biotechnology and Bioengineering 16 (1974), S. 1675-1680 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
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  • 132
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    Biotechnology and Bioengineering 16 (1974), S. 1681-1687 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
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  • 133
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    Biotechnology and Bioengineering 16 (1974), S. 567-577 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: β-Amylase (EC 3.2.1.2), obtained from barley, was chemically attached to a crosslinked copolymer of acrylamide-acrylic acid using a water-soluble carbodiimide. The derivative showed 23% β-amylase activity in relation to that of free enzyme with a coupling yield of 40% based on the amount of added β-amylase. In order to find optimal coupling conditions, the effect of pH and different carbodiimide concentrations was investigated. The enzymic activity associated with different β-amylase concentrations was further outlined. A slightly increased operational stability for the enzyme upon immobilization was observed. Markedly improved operational stability has been obtained by coupling in the presence of reduced glutathione of bovine serum albumin.
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  • 134
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    Biotechnology and Bioengineering 16 (1974), S. 623-634 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Maltase, phosphatase, malate dehydrogenase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase activities were determined in the supernatant of brewer's yeast cells from samples taken at various intervals during a 90 min treatment in a Dyno-Mill disintegrator.In an attempt to find optimum operating conditions, the following parameters were varied: speed of rotation of the agitator, flow rate, yeast concentration in the slurry and bead diameter, and the specific rate of extraction was determined for each such variation. Analysis of the data showed that, superimposed upon extraction, there was a progressive but slow loss of total activities. Enzyme release could be expressed as an approximately first-order chemical reaction. The results compared well with those of Follows et al. (Biotechnol. Bioeng.), 13, 549 (1971) and showed that the Dyno-Mill can be operated under proper conditions without significant loss of enzyme activity and with high yields.
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  • 135
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    Biotechnology and Bioengineering 16 (1974), S. 697-699 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 136
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    Biotechnology and Bioengineering 16 (1974), S. 703-722 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The complete mixing activated sludge (CMAS) system is gaining in popularity for treating both domestic and industrial wastewaters. Experience over the past 20 years has produced a simple mathematical model which can be used in both the design and the operational evaluation of CMAS systems. Laboratory pilot plants and full scale field units have furnished the basic data needed to confirm the validity of the mathematical model. The basic concepts of the model are discussed in light of field evaluations. Areas of conflict and confusion which have arisen in the past will be presented and discussed. Design examples and operational evaluations are presented for several different wastewater systems.
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  • 137
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    Biotechnology and Bioengineering 16 (1974), S. 771-787 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Anaerobic fermentation of organic solid waste can provide a significant source of fuel gas (methane). Application of this process requires a better understanding of the kinetics of the biological system. The literature is replete with kinetic studies of this process as applied to waste solids from water pollution control systems. Much of this work has been conducted in the mesophilic temperature range. Increased temperatures yield higher reaction rates that will improve the economics of the process. The rate limiting step in the fermentation of refuse is the hydrolysis of the complex organic solids, in particular cellulose. Cellulose is a major component of the refuse. A laboratory study employing domestic refuse has shown the effect of temperature on the rate of methane fermentation. The optimum mesophilic temperature was found to be 42°C, while the optimum thermophilic temperature was at least 60°C. No data was obtained beyond the 60°C temperature. Reaction rate constants are presented for anaerobic fermentation of domestic refuse. Because of the characteristics of the substrate it-was not possible to obtain the necessary measurements for evaluation of constants in the Monod model. An overall system constant was developed.
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  • 138
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    Biotechnology and Bioengineering 16 (1974), S. 847-851 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bacterial RNA virus, Qβ, has been purified in gram amounts by differential centrifugation. Final separation of the virus from host E. coli rRNA was based on the density differential in the pellet. The method provided a simplified alternative to the more conventional rate zonal or isopycnic zonal centrifugation techniques.
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  • 139
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    Biotechnology and Bioengineering 16 (1974), S. 853-858 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
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  • 140
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    Biotechnology and Bioengineering 16 (1974), S. 869-880 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Conventional sources of protein cannot meet the present or projected needs for human consumption. Single cell proteins from fermentation of petroleum and cellulosic wastes are likely sources of additional protein. The volume of cellulosic wastes is sufficient to supply all additional protein needs on a continuing basis for cellulose is a renewable resource. Both mesophilic and thermophilic microorganisms utilize cellulose at reasonable rates. Biodegradation of lignin and lignin-cellulose complexes constitutes a major obstacle to commercial utilization of cellulosic wastes. Thermophilic actinomyces appear to be the most effective organisms for single cell protein production from cellulosic wastes.
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  • 141
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    Biotechnology and Bioengineering 16 (1974), S. 1227-1243 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An intracellular, thermostable, neutral α-galactosidase (α-D-galactoside galactohydrolase EC 3.2.1.32) was produced in pilot plant quantities from a strain of Bacillus stearothermophilus. The organism was cultured at 50°C in a soluble neutral medium containing water extract of soybean meal (3%) and 0.5% yeast extract. The enzyme biosynthesis was inducible and sensitive to catabolite repression. After autolysis of the cells, the α-galactosidase was selectively and quantitatively complexed from clarified beer directly onto DEAE Sephadex; and enzyme-rich fractions were batchwise eluted with an increasing gradient of NaCl solutions. The eluates were given two consecutive isopropyl alcohol precipitations, and the aqueous solutions of the second precipitate were dialyzed and lyophilized. Final product activity recovery was 72% based on the crude fermentation beer. Best specific activity was 5.2 u/mg protein. Further laboratory purification (DEAE Sephadex and Bio-Gel P200) yielded a product with 14.2 u/mg protein.
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  • 142
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    Biotechnology and Bioengineering 16 (1974), S. 1245-1259 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The death kinetics of a strain of Saccharomyces cerevisiae were studied in an industrial scale spray drier. In solution studies, the death kinetics of yeast was found to be comparable to pathogen destruction. From the studies in drying of yeast a prediction of a 4 log cycle decrease in viable cells of pathogens could be made for normal processing conditions. This should insure the safety of spray-dried foods unless after contamination occurs. It was found that during drying, although the rate of death is high, the activation energy is greatly decreased over that of death in aqueous solution (reduction from 130 kcal/mole to 5 kcal/mole). The reduction in Ea may be attributed to the thermodynamic compensation phenomenon in which the resulting negative entropy of reaction acts to protect the cells through a water-protein interaction. However, the possibility of a change in death mechanism cannot be precluded. Overall, these results suggest the danger in extrapolating death kinetics to high temperature.
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  • 143
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    Biotechnology and Bioengineering 16 (1974), S. 1321-1343 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The overall rate of reaction of gel-immobilized glucose oxidase particles in buffered media has been investigated theoretically under two substrate diffusion limited conditions by the numerical solution of the diffusion equations. It has been found that the Enzyme Rate Equation (Atkinson and Lester), Biotechnol. Bioeng., 16, 1299 (1974), together with an analytical solution which describes the asymptotic conditions associated with a large particle size, provides an adequate estimation of the values resulting from the numerical solution outside the region of the parameter space defined by 0.4 〈 Mg′, M0′ 〈 10.When the dimensionless parameter (B0′/Bg′)(Mg′2/M0′2) is greater than unity the overall rate of reaction is limited principally by the external concentration and when the parameter has a value less than unity, by the external oxygen concentration.The results are generally applicable to enzymes whose kinetics are similar to those of glucose oxidase or for which the equation describing glucose oxidase kinetics provides an adequate curve-fit of experimental data.
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  • 144
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    Biotechnology and Bioengineering 16 (1974), S. 1399-1406 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
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  • 145
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    Biotechnology and Bioengineering 16 (1974) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 146
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    Biotechnology and Bioengineering 16 (1974), S. 1459-1469 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An apparatus is described for the rapid measurement and recording of methanogenic activity in anaerobic fermentations, and its application is demonstrated in the evaluation of the anaerobic contact process, using pear waste. The method is based on recording the rate of manometer liquid displacement in a Warburgtype vessel by means of optical sensors, appropriate electronic circuitry, and an event marking recorder or time-interval printer. Optimum conditions for measuring methanogenic activity included a pH of 6.7-6.9, a final phosphate buffer concentration of 0.07-015M, and formic and acetic acid contents of over 500 and 200 mg/liter, respectively. In comparisons of fermenter liquid and settled effluent, methanogenic activity can be assumed to be proportional to the number of methane formers present. The apparatus should be generally useful in recording rates of gas production or consumption.
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  • 147
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    Biotechnology and Bioengineering 16 (1974), S. 1549-1551 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 148
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    Biotechnology and Bioengineering 16 (1974) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 149
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    Biotechnology and Bioengineering 16 (1974), S. 1633-1644 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The β-galactosidase from Escherichia coli ATTCC-26 was partially purified and characterized. It was found to be comparable to galactosidases from other E. coli strains in stability, pH and temperature maxima, and activity requirements, but it had a more favorable ratio of activity toward lactose versus synthetic substrates. The galactosidase was immobilized on porous glass beads by three covalent bonding methods. Kinetic data for the free and bound enzymes were determined using natural and synthetic substrates. Activity characteristics of the free and immobilized enzymes were comparable, however, the bound forms were less stable to heat.
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  • 150
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    International Journal of Chemical Kinetics 6 (1974) 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 151
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    International Journal of Chemical Kinetics 6 (1974) 
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    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 152
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    International Journal of Chemical Kinetics 6 (1974), S. 245-256 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of N-phenylphthalamic acid and of N-phenylphthalimide hydrolysis in aqueous solutions of sulfuric acid has been studied. A reaction mechanism is proposed implying that unreactive forms of the reactant appear by protonization of the amide bond at the carbonyl oxygen and by dissociation of the o-carboxyl group (N-phenylphthalamic acid). Attack of the nonprotonized amide bond by the hydroxonium ion is suggested to be the rate-limiting step.
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  • 153
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    International Journal of Chemical Kinetics 6 (1974), S. 77-87 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electronically excited oxygen atoms O(21D2) have been generated by the pulsed irradiation of ozone in the Hartley-band continuum and monitored photoelectrically in absorption by time-resolved attenuation of atomic resonance radiation at λ = 115.2 nm [O(31D2°) → O(21D2)]. Collisional quenching of the excited atom has been investigated for all the noble gases, and the first absolute values for the second-order deactivation rate constants are reported. The resulting rate data are discussed in terms of a curve-crossing mechanism based on existing spectroscopic data for the noble gas oxides. The absolute rate constants are compared with previous relative rate data for the deactivation of O(21D2) by the noble gases.
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  • 154
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    International Journal of Chemical Kinetics 6 (1974) 
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    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 155
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    International Journal of Chemical Kinetics 6 (1974), S. 297-308 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rate constant for the reaction I(2P1/2) + CH3I → I2 + CH3 has been reevaluated taking into account both collisional deactivation of excited iodine atoms and loss of I2 by I2 + CH3 → I + CH3I. The reevaluation is based upon data obtained (R. T. Meyer), J. Chem. Phys., 46, 4146 (1967) from the flash photolysis of CH3I using time-resolved mass spectrometry to measure the rate of I2 formation. Computer simulations of the complete kinetic system and a closed-form solution of a simplified set of the differential equations yielded a value of 6(± 4) × 106 1./mole-sec for the excited iodine atom reaction in the temperature region of 316 to 447 K. A slight temperature dependence was observed, but an activation energy could not be evaluated quantitatively due to the small temperature range studied. An upper limit for the collisional deactivation of I(2P1/2) with CH3I was also determined (2.4 × 107 1./mole-sec).
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  • 156
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    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Competitive studies of the reactions of ground-state oxygen atoms, generated by mercury-photosensitized decomposition of nitrous oxide, have been carried out with ethylene and all the fluoroethylenes using 2-(trifluoromethyl)-propene as reference compound. From measurements at 25°C and 150°C relative rate constants have been determined and used to calculate the Arrhenius parameters shown in the following table: TextOlefin\documentclass{article}\pagestyle{empty}\begin{document}$$\frac{{A_{{\rm olefin}} }}{{A_{{\rm 2TFMP}} }}$$\end{document}ΔERef\documentclass{article}\pagestyle{empty}\begin{document}$$\frac{{A_{{\rm olefin}} }}{{A_{{\rm C}_{\rm 2} {\rm H}_{\rm 4} } }}$$\end{document}ΔEC2H4CH2—CH21.10-1.18(1.0)(0)CH2—CHF1.030.840.942.02CH2—CF20.711.490.652.67CHF—CHF (cis-)1.231.921.123.10CHF—CHF (trans-)1.400.791.271.97CF2—CHF1.060.000.961.22CF2—CF20.86-3.220.78-2.04ΔERef = Eolefin - E2TFMP and ΔEC2H4 = Eolefin - EC2H4. Units are kJ/mole.The results are compared with corresponding data for other atoms and radicals, and discussed in terms of the electronic changes produced in the double bond by fluorine substitution, and in relation to the nature of the transition state.
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  • 157
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    International Journal of Chemical Kinetics 6 (1974), S. 467-479 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nucleophilic substitution reactions in the alkyl halides, RX + Y- → RY + X-, proceeding in polar media are considered on the basis of the theory presented in Part A. It is shown that the solvent reorganization energy is the main part of the activation energy for this processes. According to calculations performed, the values of the solvent reorganization energy equal ∼2.5-3 eV for H2O and ∼ 1.8-2.3 eV for acetone. From experimental data on the kinetic isotope effect, an estimate for the splitting of nonadiabatic terms and for the slope of the potential curve v′ of the intermolecular interaction between halide ion and methyl halide near transition configuration is made. Further, the parameter v′ is used for calculating the activation entropy of substitution reactions in the methyl halides. Theoretical activation energies and activation entropies agree with experimental values. In the framework of theory presented an interpretation of change of Ea and the preexponential factor with the type of alkyl halide is given.
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  • 158
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    International Journal of Chemical Kinetics 6 (1974), S. 371-382 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the thermal decomposition of diallylamine to propylene and prop-2-enaldimine have been studied in the gas phase in presence of an excess of methylamine over the temperature range of 532.7 to 615.6°K, using a static reaction system. Methylamine reacted with the unstable primary product prop-2-enaldimine, forming the thermally stable N-methyl prop-2-enaldimine.First-order rate constants, based on the internal standard technique, fit the Arrhenius relationship log k(s-1) = (11.04 ± 0.13) - (37.11 ± 0.33 kcal/mole)/2.303 RT. They were independent on the initial total pressure (46-340 torr), the initial pressure of diallylamine (9.2-65 torr), or methylamine as well as the conversion attained. Despite an apparent surface sensitivity, the reaction is essentially homogeneous in nature as demonstrated by experiments carried out in a packed reaction vessel.The observed activation parameters for the title reaction together with those observed earlier for triallylamine and allylcyclohexylamine are consistent with the proposed concerted reaction mechanism involving a cyclic 6-center transition state. The observed substituent effects suggest a nonsynchronous mode of bond breaking and bond formation.
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  • 159
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    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 160
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    International Journal of Chemical Kinetics 6 (1974), S. 457-466 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Activation energies for substitution reactions of the type AC + B → A + CB, occurring in polar media and characterized by an abrupt change of the term along two coordinates have been calculated within the framework of the quantum-mechanical theory of chemical reactions. In the case of nonadiabatic processes, the transmission coefficient and activation energy for these reactions are expressed in terms of characteristic parameters of the medium (reorganization energy, effective frequency of solvent fluctuation polarization) and the potential energy curves for intermolecular interactions between the reactants (AC and B) and between the products (A and BC).
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  • 161
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    Topics: Chemistry and Pharmacology
    Notes: The thermal decomposition of ethylallylether (EAE) has been studied in the gas phase over the temperature range of 560-648°K. Propylene and acetaldehyde are the only reaction products observed. The reaction is apparently homogeneous in nature and independent of the pressure of EAE and of added foreign gases. The experimetally determined first-order rate constants, using the internal standard technique, fit the Arrhenius relationship log k(s-1) = 11.84 ± 0.29 - (43.57 ± 0.77 kcal/mole)/2.303RT. Independently the same rate constants are obtained, based on the amounts of products formed. The observed activation parameters are in general agreement with expectations based on the concept of a 6-center 1,5-H-shift retro-“ene” reaction mechanism, and they agree with previous results obtained for the similar reactions involving alkylallylamines and olefins.
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  • 162
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    International Journal of Chemical Kinetics 6 (1974), S. 453-456 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A competitive method involving the direct measurement of radical concentrations by EPR spectroscopy has been used to show that in solution at 25°C the rate constants for the bimolecular self-reactions of ethyl, isopropyl, tert-butyl, cyclopentyl, and trichloromethyl are all approximately equal, as had been indicated previously by direct measurement of the rate constants for decay of these radicals.
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  • 163
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    International Journal of Chemical Kinetics 6 (1974), S. 507-516 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Predictions of the “redox” and “complex” schemes for the Fe3+ catalyzed decomposition of H2O2 have been compared with published and new experimental data by numerical integratior of the appropriate complete sets of differential equations. Apparent discrepancies for the redox scheme at high Fe3+/H2O2 ratios are shown to disappear in the complete treatment, and inconsistencies of the complex scheme with both kinetic data and spectroscopic measurements are pointed out.
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  • 164
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    International Journal of Chemical Kinetics 6 (1974), S. 531-543 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of reactant self-heating or cooling upon rate data is considered, and three approaches to the problem of obtaining valid kinetic parameters are described in detail. A comparison of these approaches emphasises the need to assess and allow for thermal effects during the initial planning of kinetic experiments if satisfactory results are to be acquired. An integrated rate expression is given for use with nonisothermal data, and is used to provide correction factors for rate constants which have been derived without allowance for thermal effects.
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  • 165
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    International Journal of Chemical Kinetics 6 (1974), S. 553-565 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of O(3P), prepared from the Hg photosensitization of N2O, with C2HCl3 was studied at 25°C. The products of the reaction in the absence of O2 were CO, CHCl3, and polymer (as well as N2 from the N2O). The quantum yields of CO and CHCl3 were 0.23 ± 0.01 and 0.14 ± 0.05, is respectively independent of reaction conditions. The reaction mechanism is with k14a/k14 = 0.23, where k14a + k14b. Most of the HCl and CCl2 combine to form CHCl3, but some other products must also be formed to account for the difference in the CO and CHCl3 quantum yields. The C2HCl3O* adduct polymerizes without involving additional C2HCl3 molecules, since the quantum yield of C2HCl3 disappearance, —Φ{C2HCl3}, was about 1.0 at high values of [N2O]/[C2HCl3]. The rate coefficient for the reaction of O(3P) with C2HCl3 is 0.10 that for the reaction of O(3P) with C2F4.In the presence of O2 the free radical chain oxidation occurs because of the reaction The main product is CHCl2CCl(O) with smaller amounts of CO and CCl2O, and some CO2. The chain lengths were long and values of — Φ {C2HCl3} up to 90 were observed.
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  • 166
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    International Journal of Chemical Kinetics 6 (1974), S. 587-595 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the decay of hydroxyl radicals in the presence of excess acetylene were studied at pressures in the vicinity of 1 torr and at ambient temperature in a tubular discharge-flow reactor. Hydroxyl radicals were produced by the reaction of atomic hydrogen with nitrogen dioxide, H + NO2 → OH + NO. The concentration of hydroxyl was followed by line absorption photometry at 308.939 nm and 308.328 nm. Second-order rate coeffcients were determined in two sets of experiments. The initial concentration ratio [C2H2]0/[OH]0 was in the range of 2.3 to 13.2 in the first set, and 14 to 125 (owing to greater hydroxyl detection sensitivity) in the second set. Values of the second-order rate coefficient obtained were nk5 = (2.9 ± 0.3) × 10-13 cm3/molec-sec in the first set, and nk5 = (2.1 ± 0.6) × 10-13 cm3/molec-sec in the second set, where n is the stoichiometric coefficient of OH. A value of the bimolecular rate constant k5 = (2.0 ± 0.6) × 10-13 cm/molec-sec is consistent with both sets of data, as well as an earlier determination.
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  • 167
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    International Journal of Chemical Kinetics 6 (1974) 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 168
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    International Journal of Chemical Kinetics 6 (1974), S. 631-641 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal decomposition of t-butylmethyl ether has been studied using the VLPP technique. The recommended Arrhenius parameters for the molecular elimination, reaction (1), are A(800°K) = 101 3, 9 sec-1 and Ea (800°K) = 59.0 ± 1.0 kcal/mole. No radical reactions occur under the conditions used. These parameters are in good agreement with earlier experimental work and with theoretical estimates of both A and E.
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  • 169
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    International Journal of Chemical Kinetics 6 (1974), S. 829-848 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chemical reactions of SO2(3B1) molecules with cis- and trans-2-butene have been studied in gaseous mixtures at 25°C by excitation of SO2 within the SO2(3B1) → SO2(+, 1A1) ‘forbidden’ band using 3500-4100-Å light. The initial quatum yields of olefin isomerization were determined as a function of the [SO2]/[2-butene] ratio and added gases, He and O2. The kinetic treatment of these data suggests that there is formed in the SO2(3B1) quenching step with either cis- or trans-2-butene, some common intermediate, probably a triplet addition complex between SO- and olefin. It decomposes very rapidly to form the 2-butene isomers in the ratio [trans-2-butene]/[cis-2-butene] = 1.8. In another series of experiments SO2 was excited using a 3630 ± 1-Å laser pulse of short duration, and the SO2(3B1) quenching rate constants with the 2-butenes were determined from the SO2(3B1) lifetime measurements. The rate constants at 21°C are (1.29 ± 0.18) × 1011 and (1.22 ± 0.15) × 1011 l/mole·sec with cis-2-butene and trans-2-butene, respectively, as the quencher molecule. Within the experimental error these quenching constants equal those derived from the quantum yield data. Thus the rate-determining step in the isomerization reaction is suggested to be the quenching reaction, presumably the formation of the triplet SO2-2-butene addition complex. In a third series of experiments using light scattering measurements, it was found that the aerosol formation probably originates largely from SO3 and H2SO4 mist formed following the reaction SO2(3B1) + SO2 → SO3 + SO(3Σ-). Aerosol formation from photochemically excited SO2-olefin interaction is probably unimportant in these systems and must be unimportant in the atmosphere.
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  • 170
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    International Journal of Chemical Kinetics 6 (1974), S. 887-891 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The decaying absorption of CH3 radicals at 216.4 nm has been followed over more than three half-lives using a photoelectric split-beam kinetic spectrometer. The rate constant for recombination kr was found to be (5.60 ± 0.76) × 10-11 cm3/molecule·s.
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  • 171
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    International Journal of Chemical Kinetics 6 (1974), S. 899-920 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Singlet methylene was reacted with cyclopentadiene to give chemically activated bicyclo[3.1.0]hex-2-ene (BCH). The rate of isomerization of BCH to 1,4-cyclohexadiene, 1,3-cyclohexadiene, cis-1,3,5-hexatriene, and l-methylcyclopentadiene is compared with calculated rate constants using the RRKM theory and measured or estimated thermal Arrhenius parameters. Subsequent isomerizations of the C6H8 products are also measured and calculated. These include 1,4-cyclohexadiene to benzene and the reversible reactions between 1,3-cyclohexadiene, cis-1,3,5-hexatriene, and trans-1,3,5-hexatriene. The results provide new data for several of these reactions which have not been observed in thermal studies. Agreement between the observed and calculated rates using the strong collision assumption is satisfactory except for the trans-1,3,5-hexatriene to cis-1,3,5-hexatriene reaction.
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  • 172
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    International Journal of Chemical Kinetics 6 (1974), S. 813-828 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Study of the reaction by very-low-pressure pyrolysis (VLPP) in the temperature range of 550-850°K yields for the high-pressure Arrhenius parameters \documentclass{article}\pagestyle{empty}\begin{document}$$\log {\rm }\,k_{\rm 1} = (15.6 \pm 0.5) - (36.0 \pm 1.0)/\theta {\rm \,(sec}^{{\rm - 1}})$$\end{document} where θ = 2.303RT in kcal/mole. These in turn yield for the high-pressure second-order recombination of tBu + NO, k-1 = (3.5 ± 1.7) × 109 1./mole·sec at 600°K. For the competing reaction l./mole·sec and E4 ≥ 4.2 kcal/mole. The bond dissociation energy DHo (tBu-NO) was determined to be (39.5 ± 1.5) kcal/mole, both from the equilibrium constant and from the activation energy of reaction (1), obtained from RRKM calculations. A ‘free-volume’ model for the transition state for dissociation is consistent with the data. A limited study of the system at 8-200 torr showed an extremely rapid inhibition by products and a very complex set of products.
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  • 173
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    International Journal of Chemical Kinetics 6 (1974), S. 875-876 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 174
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    International Journal of Chemical Kinetics 6 (1974), S. 893-897 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal isomerization of 1,1-divinylcyclopropane has been investigated in the gas phase in the temperature range of 238 to 288°C and for pressures in the range of 4 to 12 torr. The isomerization to 1-vinylcyclopentene is homogeneous and kinetically first order and almost certainly unimolecular. The rate constants yield the Arrhenius equation \documentclass{article}\pagestyle{empty}\begin{document}$$\log {\rm }k({\rm s}^{ - 1} {\rm)} = 13.53 \pm 0.13 - (42.45 \pm 0.33{\rm \,kcal/mole})/RT\,{\rm In 10}$$\end{document} or \documentclass{article}\pagestyle{empty}\begin{document}$$\log {\rm }k({\rm s}^{ - 1} {\rm)} = 13.53 \pm 0.13 - (117.6 \pm 1.4{\rm \,kJ/mole})/RT\,{\rm In 10}$$\end{document} The assumption of a similar transition state for this isomerization with that of l-methyl-l-vinylcyclopropane leads to a value for an alkylpentadienyl radical stabilisation energy of 19.2 ± 1.6 kcal/mole (80.4 ± 6.7 kJ/mole), and this value is compared with other estimates.
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  • 175
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    International Journal of Chemical Kinetics 6 (1974), S. 15-28 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oxidation of inositol by quinquevalent vandadium in acid medium is a first-order reaction both in vanadium (V) and inositol. The stoichiometry of the reaction is consistent with the use of two equivalents of vanadium (V) per mole of inositol with the formation of one mole of inosose. The reaction is catalyzed both by sulfuric and perchloric acid, but the rate is faster in sulfuric acid than in perchloric acid. In 1M-6M perchloric acid solutions the reaction has shown a variable order in H+, but in solutions of 2M-5M sulfuric and perchloric acid of constant ionic strength, the rate has a linear dependence on [H+]2. There is also a linear correlation between the rate and bisulfate ions in sulfuric acid at constant hydrogen ion concentration. The energy of activation is found to be 19 kcal/mole and a negative entropy value of - 14 e.u. A suitable mechanism, consistent with the kinetics in 2M-5M acid solutions, is suggested and the values of various rate constants are evaluated.
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  • 176
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    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Very strong laser emission at 5 μm was detected when SO2 and CHBr3 were flash photolyzed in the vacuum ultraviolet (λ ≥ 165 nm) in the presence of a large amount of diluent (SF6, He, or Ar). About 110 vibration-rotation transitions ranging from Δv = 18 → 17 to 3 → 2, except 16 → 15, were identified. The primary reactions leading to the CO stimulated emission are as follows: The product analysis results and the variation of laser intensity with flash energy and SO concentration indicate that the following side reactions are also occurring. Addition of a small amount of O2 enhances the laser output by both eliminating these side reactions and simultaneously producing vibrationally excited CO via reaction (8), which has been previously shown to generate CO stimulated emission. The effects of various reactive (NO and H2) and inert (He, Ar, SF6, CO, N2, N2O, and CO2) gases have been examined. All additives (P ≤ 20 torr), except NO and H2, increase the total laser output. N2O enhances the power most efficiently, whereas CO, N2, and CO2 are less effective and have similar efficiencies. The enhancement of the laser intensity by these near-resonant gases is ascribed to the depletion of CO population at lower levels which thus increases the rates cascading from higher levels. NO and H2 quench the laser output by chemically reducing the concentration of the CH radical.
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  • 177
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    International Journal of Chemical Kinetics 6 (1974), S. 61-75 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A kinetic study of lead atoms in the spin orbit states, Pb(63P1) and Pb Pb(63P2), 0.969 and 1.320 eV, respectively, above the 63P0 ground state, has been carried out by atomic absorption spectroscopy. The electronically excited lead atoms were generated by the pulsed irradiation of lead tetraethyl and monitored photoelectrically by time-resolved attenuation of resonance radiation. The decay of the two atomic states has been studied in the presence of He, Ar, H2, D2, N2, O2, CO, NO, CO2, N2O, CH4, C2H4, C2H2 CF4, SF6, and PbEt4, and rate constants for the collisional quenching by these gases are reported. The resulting data are compared with those for the deactivation of other atomic spin orbit states of comparable energy. In general, the higher energy state, Pb(63P2), is found to be deactivated more rapidly. It would appear that the magnitude of the electronic energy to be transferred on collision governs the rates of quenching, at least where a weak interaction potential is involved, and that for most gases, deactivation of Pb(63P2) proceeds via Pb(63P1).
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  • 178
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    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation and characterization of the iron(II) complex of the hexadentate Schiff base ligand NN‴-bis-[α-(2-pyridyl)benzylidene]triethylenetetramine are reported. Kinetic patterns and rate constants for aquation of this complex, and for its reactions with hydroxide, cyanide, and peroxodisulphate have been determined. Activation parameters for the reaction with cyanide, in aqueous solution, are ΔH
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  • 179
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    International Journal of Chemical Kinetics 6 (1974), S. 169-228 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methods are discussed for the production and detection of the hydroperoxyl radical for use in gas phase kinetic studies. Rate constants for gas phase reactions of the hydroperoxyl radical with itself, H2, H2O, CO, NO, SO2, O3, C2H6, C3H8, i-and n-C4H10, C2H4, i-C4H8, HCHO, C2H5CHO, n-C3H7CHO, Br, O, OH, and H are critically evaluated. Recommended or estimated rate constant expressions with associated error limits are given applicable over specified temperature ranges (normally 300-1000°K). The reactivity of HO2 compared with OH, O, H, F, Cl, Br, CH3, and CH3O is presented in tabular form and the implications for atmospheric chemistry are discussed.
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  • 180
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    International Journal of Chemical Kinetics 6 (1974), S. 257-263 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pyrolysis of C6F5I has been studied by the toluene carrier method over the temperature range of 900-978°K with contact times of 0.4-2.0 seconds and total pressures of 11.2-19.5 torr. Percent decomposition ranged from 8.6 to 97.7%. With toluene-to-C6F5I molar ratios of greater than 150, 85-100% of the C6F5 released abstracts a hydrogen atom from toluene to produce C6F5H. No significant quantities of I2 were observed and the only major gaseous product was HI. Within the limits of the experimental method the decomposition of C6F5I was first order and homogeneous.Least squares analysis of log k1 and 103/T(C6F5I → C6F5 + I) values gives \documentclass{article}\pagestyle{empty}\begin{document}$${\rm log}\,k_1 ({\rm s}^{- 1}) = 15.9 - 69,200/4.576T $$\end{document} while a weighted line of best fit yields. \documentclass{article}\pagestyle{empty}\begin{document}$${\rm log}\,k_1 ({\rm s}^{- 1}) = 15.4 - 67,000/4.576T$$\end{document} Based on this latter equation D[C6F5—I] at 298°K is estimated as 66.2 kcal/mole.
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  • 181
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    International Journal of Chemical Kinetics 6 (1974), S. 265-277 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the gamma-radiation-induced free radical chain reaction in solutions of C2Cl3F in cyclohexane (RH) was investigated over a temperature range of 87.5-200°C. The following rate constants and rate constant ratios were determined for the reactions: \documentclass{article}\pagestyle{empty}\begin{document}$$\begin{array}{*{20}c} {{\rm (2a)}} & {{\rm R} + {\rm C}_{\rm 2} {\rm Cl}_{\rm 3} {\rm F} \to {\rm RCClFCCl}_{\rm 2}} \\ \end{array}$$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$\begin{array}{*{20}c} {(2{\rm b})} & \to \\ \end{array}{\rm RCCl}_{\rm 2} {\rm CClF}$$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$\begin{array}{*{20}c}{{\rm (3a)}} & {{\rm RCClFCCl}_{\rm 2} \to {\rm RCF}}\\ \end{array}{\raise1pt\hbox{$\Relbar \kern-4pt{\Relbar}$}}{\rm CCl}_{\rm 2} + {\rm Cl}$$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$\begin{array}{*{20}c} {{\rm (4a)}} & {{\rm RCClFCCl}_{\rm 2} + {\rm RH} \to {\rm RCClFCCl}_{\rm 2} {\rm H} + {\rm R}} \\ \end{array}$$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$\log {\rm }k_{2a} ({\rm mole}^{{\rm - 1}} 1.\,{\rm sec}^{{\rm - 1}}) = (8.64 \pm 0.35) - (6.38 \pm 0.41)/\theta ^1$$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$\log {\rm }k_{{\rm 2b}} /k_{{\rm 2a}} = (- 0.03 \pm 0.15) - (2.39 \pm 0.28)/\theta$$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$\log {\rm (}k_{3{\rm a}} /k_{4{\rm a}})({\rm mole}\,1.^{{\rm - 1}}) = (6.17 \pm 0.10) - (10.14 \pm 0.18)/\theta$$\end{document} In competitive experiments in ternary solutions of C2Cl4 and C2Cl3F in cyclohexane the rate constant ratio k2c/k2a was determined \documentclass{article}\pagestyle{empty}\begin{document}$$\begin{array}{*{20}c} {{\rm (2c)}} & {{\rm R} + {\rm C}_{\rm 2} {\rm Cl}_{\rm 4} \to {\rm RC}_{\rm 2} {\rm Cl}_{\rm 4}} \\ \end{array}$$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$\log {\rm }k_{{\rm 2c}} /k_{{\rm 2a}} = (0.13 \pm 0.06) - (1.20 \pm 0.12)/\theta$$\end{document} By comparing with previous data for the addition of cyclohexyl radicals to other chloroethylenes it is shown that in certain cases the trends in activation energies for cyclohexyl radical addition can be correlated with the C—Cl bond dissociation energies in the adduct radicals.
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  • 182
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    International Journal of Chemical Kinetics 6 (1974), S. 323-336 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The substitution of N-alkyl substituted ethylenediamines for chloride ions in the rapidly equilibrating system \documentclass{article}\pagestyle{empty}\begin{document}$${\rm PdCl}_{\rm 4} ^{{\rm 2 - }} {\rm + H}_{\rm 2} {\rm O}\rightleftharpoons{\rm PdCl}_{\rm 3} ({\rm H}_2 {\rm O)}^{\rm - } + {\rm Cl}^{\rm - }$$\end{document} has been investigated in aqueous acid medium. The kinetic data can be accommodated by the general rate law \documentclass{article}\pagestyle{empty}\begin{document}$$k_{{\rm obs}} = \left\{ {\frac{k}{{\left[{{\rm H}^{\rm + }} \right]}} + \frac{{k'}}{{\left[{{\rm H}^{\rm + } } \right]\left[{{\rm Cl}^{\rm - } } \right]}}} \right\}\left[{{\rm N}_{\rm n} {\rm N}_{\rm m} {\rm en}} \right]_{{\rm total}}$$\end{document} where n = 0, 1, or 2 and m = 0, 1, or 2, depending on whether none, one, or two methyl groups are attached to the two nitrogen atoms of ethylenediamine. Reaction with the most heavily substituted ethylenediamine, namely, N2N2en discloses a change of the mentioned rate law to \documentclass{article}\pagestyle{empty}\begin{document}$$k_{{\rm obs}} = \left\{ {\frac{{k''}}{{\left[{{\rm H}^{\rm + } } \right]}} + \frac{{k'''\left[{{\rm Cl}^{\rm - } } \right]}}{{\left[{{\rm H}^{\rm + } } \right]}}} \right\}\left[{{\rm N}_{\rm 2} {\rm N}_{\rm 2} {\rm en}} \right]_{{\rm total}}$$\end{document} on going from a lower to a higher chloride ion concentration range. This change in the mathematical form of the rate law can be explained in terms of an ion-pair association of N2N2enH+ and free chloride ions.
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  • 183
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    International Journal of Chemical Kinetics 6 (1974), S. 383-394 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An inhibitor method for measuring the initiation rate is proposed for the system Fe3+ + H2O2. C(NO2)4 was used as inhibitor. The number of chains terminated by one C(NO2)4 molecule was estimated in specific photochemical experiments and found to be unity. The initiation appeared to involve two processes. The first is proportional to the first power of ferric ion concentration, and the second to the second power. The rate constants and activation energies of these processes are determined. Allowance for the second initiation process permitted qualitative and quantitative description of various reported data on H2O2 decomposition rates over a wide range of Fe3+, H2O2, and H+ concentrations.
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  • 184
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    International Journal of Chemical Kinetics 6 (1974), S. 493-506 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of the addition of hydrogen chloride on the photolysis of carbon tetrachloride in the presence of cyclohexane has been investigated in a companion paper. The data enable the rate constant ratio k8/(k5)1/2 to be determined. Since k-8 is well established, k5 can be estimated from known thermochemical data. The validity of the thermochemical derivation is checked by applying it to trifluoromethyl radicals. The photolysis of bromotrichloromethane and carbon tetrachloride in the presence of hydrogen chloride has been investigated over a range of temperatures. From these results and assuming reaction (5) has no activation energy, Arrhenius parameters for reaction (8) have been determined: The activation energies for the reaction of methyl, trichloromethyl, and trifluoromethyl radicals with hydrogen chloride are compared, and at first sight surprising results are rationalized in terms of relative electronegativity.
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  • 185
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    International Journal of Chemical Kinetics 6 (1974), S. 527-530 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Measurements of rates of oxygen absorption and steady-state peroxy radical concentrations for the autoxidation of tetralin in the presence of tert-butyl hydroperoxide have shown that the rate constant for reaction of the tert-butylperoxy radical with tetralin at 60°C is approximately 11.0 M-1 s-1. This rate constant is about a factor of 4 larger than the value recently reported by Niki, Okayasu, and Kamiya for this reaction.The present work emphasizes that great care should be taken when the hydroperoxide method is used to estimate cross-propagation rate constants for a substrate as reactive as tetralin at a temperature as high as 60°C.
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  • 186
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    International Journal of Chemical Kinetics 6 (1974), S. 567-572 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The decomposition of acetylenedicarboxylic acid in acetophenone was studied in the temperature range of 100-130°C. The rate constants and activation parameters for the consecutive pair of first-order steps (each yielding carbon dioxide) were calculated. Hydrogen kinetic isotope effects were also studied. Comparisons were made with the decompositions of oxalic acid and malonic acid. An intramolecular H—C transfer is believed to be the main part of the reaction coordinate in addition to the C—C bond breaking.
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  • 187
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    International Journal of Chemical Kinetics 6 (1974), S. 777-786 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chloroethanes react with aqueous caustic to yield either elimination or substitution products. The reaction rates were measured for the dichloroethanes, trichloroethanes, tetrachloroethanes, and pentachloroethane between 283 and 353°K. The constants of HCl eleminations referring to the rate equation \documentclass{article}\pagestyle{empty}\begin{document}$$r = k[{\rm OH}^{\rm - }][{\rm dissolved \,substrate]}$$\end{document} are given by \documentclass{article}\pagestyle{empty}\begin{document}$${\rm 1,2 - C}_{\rm 2} {\rm H}_{\rm 4} {\rm Cl}_{\rm 2} {\rm }\,k = 10^{10.99 \pm 0.03} \exp (- 23,000 \pm 50RT)$$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$${\rm 1,1,2 - C}_{\rm 2} {\rm H}_{\rm 3} {\rm Cl}_{\rm 3} {\rm}\,k = 10^{13.99 \pm 0.03} \exp (- 22,400 \pm 50/RT)$$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$${\rm 1,1,1,2 - C}_{\rm 2} {\rm H}_{\rm 2} {\rm Cl}_{\rm 4} {\rm }\,k = 10^{15.45 \pm 0.14} \exp (- 25,800 \pm 210/RT)$$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$${\rm 1,1,2,2 - C}_{\rm 2} {\rm H}_{\rm 2} {\rm Cl}_{\rm 4} {\rm }\,k = 10^{16.40 \pm 0.05} \exp (- 22,550 \pm 70/RT)$$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$${\rm C}_{\rm 2} {\rm HCl}_{\rm 5} {\rm }\,k = 10^{12.50 \pm 0.08} \exp (- 15,200 \pm 110/RT)$$\end{document} all rate constants being in 1./mole·s and R in cal/mole· deg.With ethyl chloride, 1,1-dichloroethane, and 1,1,l-trichloroethane, the elimination is not observed and a slow substitution takes place. The influence of chlorine substituents on both sides of the molecule on mechanism and rate parameters is discussed.
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  • 188
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The occurrence of anchimeric assistance in the vapor-phase thermolysis of anti- and syn-7-acetoxy-7-methylnorbornene and 7-acetoxy-7-methylnorborane has been investigated. The relative rates of thermolysis were found to be 1.9, 0.87, and 1.0, respectively. The nature of the transition state for ester thermolysis is discussed in light of the small amount of anchimeric assistance found in the thermolysis of the anti-isomer.
    Additional Material: 1 Tab.
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  • 189
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    International Journal of Chemical Kinetics 6 (1974), S. 877-885 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The heats of formation of C3 and C4 alkyl nitrites (RONO) have been determined via their heats of combustion by bomb calorimetry, thereby providing a complete set of values of ΔHºf for C1-C4 alkyl nitrites. The experimental values are in excellent agreement with values derived from group additivity rules. For branched compounds these calculations involve corrections for gauche interactions. In these cases, the gauche interactions are reflected in the activation energies E1 determined by recent kinetic studies, required for breaking the RO-NO bond. The heats of formation of the alkoxy radicals involved together with ΔHºf(NO) = 21.6 kcal/mole leads to the result D(RO-NO) = 41.5 ± 1 kcal/mole. The concordance between D(thermochemical) and D(kinetic), unlike previous kinetic studies, implies that E2 = 0 ± 1 kcal/mole.
    Additional Material: 10 Tab.
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  • 190
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    International Journal of Chemical Kinetics 6 (1974), S. 337-357 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Absolute values of the rate constants for the reaction of hydrogen atoms with cyclic olefins in the gas phase have been measured in a discharge-flow system under 3.5, 16, and 22 torr Ar at 23°C. The attenuation of hydrogen atom concentration in the reaction tube in the presence of a large excess of olefin was measured with an ESR spectrometer, and the products were analyzed by gas chromatography. Cyclic C6 hydrocarbons were the only significant products obtained when the hydrogen atom concentration was 2.6 × 10-10 mole/1., the olefin concentration was in the range of 9 to 22 × 10-8 mole/1., and the pressure was 16 torr Ar. The values for the rate constants for reaction with cyclohexadiene-1,3, cyclohexadiene-1,4, and cyclohexene are, respectively, (9 ± 2) × 108, (12 ± 1) × 108, and (6 ± 1) × 108 l./mole-sec, and they are not changed significantly by a sixfold change in total pressure. The fraction of the total interaction that proceeds by addition is 84% in the cyclohexadiene-1,3 system, but only 18% in the cyclohexadiene-1,4 system, and the cyclohexadienyl radical is therefore the dominant radical species in the latter system. The pattern of interaction between the hydrogen atom and the cyclohexadienyl radical was determined, and comprises 65% of disproportionation, and 13% and 23% of combination to yield cyclohexadiene-1,3 and cyclohexadiene-1,4, respectively. These results are consistent with the general patterns of reactivity emerging from studies of the reactions between free radicals and olefins in related systems.
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  • 191
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    International Journal of Chemical Kinetics 6 (1974), S. 395-400 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Different possible mechanisms for the gas phase reaction of formation of bromine chloride from bromine and chlorine are discussed. The rate of the reaction has been deduced from photometric measurements in conventional static reactors of surface-to-volume ratio ranging between 0.6 and 3 cm-1, at temperatures between 51 and 113°C. Experimental data show that (1) the observed reaction is predominantly heterogeneous, and (2) the homogeneous reaction must proceed by an atomic chain mechanism initiated by Br atoms.
    Additional Material: 1 Ill.
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  • 192
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    International Journal of Chemical Kinetics 6 (1974), S. 417-428 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the reaction between ozone and allene (A) were studied in the range of 226 to 325°K in the gas phase. Initial O3 pressures varied from 0.01 to 0.7 torr and allene pressures varied from 0.05 to 6 torr. At the higher initial O3 pressures the most important product was O2 followed by CO, H2O, CO2, and C2H4. Oxygen balances averaging about 110% were obtained, which implies that no important oxygenated products were missed. However, carbon balances were only about 50% and hydrogen balances were even less, so that unidentified hydrocarbons were presumably formed. The rate law found was - d[O3]/dt = k1[O3][A] + k2a[O3]2[A]/[O3]0 where log k1(M-1sec-1) = 6.0 ± 0.7 - (5500±1000)/2.30RT and log k2a(M-1sec-1) = 6.9 ± 0.7 - (6200 ± 800/2.30RT). A mechanism is proposed which accounts for the rate law and the observed stoichiometry of O2 formed-O3 used. This involves a heterogeneous catalyzed decomposition of O3. The rate constant k1 is identified with the primary addition reaction A + O3 → AO3, and this rate constant is compared with those from other O3 addition reactions.
    Additional Material: 9 Ill.
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  • 193
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    International Journal of Chemical Kinetics 6 (1974), S. 401-416 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using the technique of flash photolysis-resonance fluorescence, absolute rate constants have been measured for the reaction H + O2 + M → HO2+M over a temperature range of 220-360°K. Over this temperature range, the data could be fit to an Arrhenius expression of the following form: \documentclass{article}\pagestyle{empty}\begin{document}$$k_{{\rm Ar}} = (6.75{\rm } \pm {\rm }1.1){\rm } \times {\rm }10^{ - 33} \exp {\rm }[685{\rm } \pm {\rm }128{\rm cal/mole]/}RT$$\end{document} The units for kAr are cm6/mole-s. At 300°K the relative efficiencies for the third-body gases Ar:He:H2:N2:CH4 were found to be 1.0:0.93:3.0:2.8:22. Wide variations in the photoflash intensity at several temperatures demonstrated that the reported rate constants were measured in the absence of other complex chemical processes.
    Additional Material: 5 Ill.
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  • 194
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    International Journal of Chemical Kinetics 6 (1974), S. 481-492 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photolysis of azocyclohexane, carbon tetrachloride, and cyclohexane at 360 nm has been investigated over a wide temperature range. At moderate temperatures a chain reaction ensues from which the following approximate rate constants could be determined assuming 2CCl3. → C2Cl6, k5 = 109.7 (303-673K): The really striking feature of the results is that they show that termination in bicyclohexyl [reaction (7)] is extremely slow: The root-mean-square rule for estimating the cross-combination rate is also followed.The photolysis of carbon tetrachloride and cyclohexane at 250 nm has also been investigated. The reaction is complicated by the occurrence of two concurrent photolytic processes, the main one yielding trichloromethyl radicals and chlorine atoms, and the subsidiary one yielding dichlorocarbene and molecular chlorine. Nonetheless the results from this reaction can be interpreted in the medium temperature range 360-430K, where long chains are present, in terms of the rate constants derived from the azocyclohexane system.
    Additional Material: 2 Ill.
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  • 195
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    International Journal of Chemical Kinetics 6 (1974), S. 517-526 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photochemistry of 1,1,1-trifluoromethylazomethane has been partially characterized. The quantum yield for N2 formation from photolysis at 366 nm and room temperature was unity at low pressure and decreased to 0.5 at 630 torr. At room temperature the principal products were C2H6, C2F6, CH3CF3 (or CH2CF2 + HF at reduced pressures), plus substituted hydrazines, which mainly arise from addition of CF3 to the parent followed by combination of these radicals with CH3 or CF3. These fluorinated methyl hydrazine products detract from the general utility of CF3-N2-R compounds as sources for simultaneous study of the chemistry of CF3 and R radicals. At room temperature the hydrazine products accounted for more than 50% of the total yield; however, these products can be reduced by lowering the temperature and at 195°K their yields are negligible. The quantum yield for intramolecular (direct) formation of CH3CF3 + N2 was shown to be ≤0.002.
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  • 196
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    International Journal of Chemical Kinetics 6 (1974), S. 545-552 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The addition of propene to cyclohexa-1,3-diene has been studied between 512 and 638°K at pressures between 70 and 640 torr. The products are endo- and exo-5-methylbicyclo [2.2.2] oct-2-ene, and their formations are second order. The rate constants (in 1./mole-sec) are given by \documentclass{article}\pagestyle{empty}\begin{document}$$\log _{10} k_{{\rm endo}} = - (26070 \pm 80)/4.576T + (5.74 \pm 0.03)$$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$\log _{10} k_{{\rm exo}} = - (30090 \pm 80)/4.576T + (6.66 \pm 0.03)$$\end{document} The results are discussed in terms of a biradical mechanism.
    Additional Material: 3 Ill.
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  • 197
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    International Journal of Chemical Kinetics 6 (1974), S. 725-739 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of ozone with simple olefins have been studied between 6 and 800 mtorr total pressure in a 220-m3 reactor. Rate constants for the removal of ozone by an excess of olefin in the presence of 150 mtorr oxygen were determined over the temperature range 280 to 360° K by continuous optical absorption measurements at 2537 Å. The technique was tested by measuring the rate constants k1 and k2 of the reactions (1) NO + O3 → NO2 + O2 and (2) NO2 + O3 rarr; NO3 + O2 which are known from the literature. The results for NO, NO2, C2H4, C3H6, 2-butene (mixture of the isomers), 1,3→butadiene, isobutene, and 1,1 -difluoro-ethylene are 1.7 × 10-1 4 (290°K), 3.24 × 10-17 (289°K), 1.2 × 10-1 4 exp (-4.95 ± 0.20/RT), 1.1 × 10-1 4 exp (-3.91 ± 0.20/RT), 0.94 × 10-1 4 exp ( -2.28 ± 0.15/RT), 5.45 ± 10-1 4 exp ( -5.33 ± 0.20/RT), 1.8 ×10-17 (283°K), and 8 × 10-20 cm3/molecule ·s(290°K). Productformation from the ozone-propylene reaction was studied by a mass spectrometric technique. The stoichiometry of the reaction is near unity in the presence of molecular oxygen.
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  • 198
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    International Journal of Chemical Kinetics 6 (1974), S. 773-776 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 199
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    International Journal of Chemical Kinetics 6 (1974), S. 801-811 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of added nucleophiles (methanol and 1,4-butanediol) on the steady-state kinetics of α-chymotryptic hydrolysis of a series of N-acetyl-L-amino acid methyl esters, R-CH(NHCOCH3)C(O)OCH3, has been studied. As a result, the rate and equilibrium constants of the ‘elementary’ steps of the enzyme process have been determined.It has also been demonstrated how the free energy-reaction coordinate profile changes if the structure (the size of the hydrocarbon chain) of the ‘chemically inert’ substrate fragment R is varied. The effects observed can be described by the following equation: where ΔGs and ΔGa are the free energies of formation of metastable intermediates, i.e., the enzyme-substrate complex and the acylenzyme, respectively, ΔG2≠ and ΔG3≠ are the free energies of activation for the chemical steps, i.e., enzyme acylation and acylenzyme hydrolysis, respectively; and ΔGtrans(R) is the free energy of transfer of substrate group R from water into a nonaqueous solvent.To explain the results obtained, a mechanism for enzyme-substrate interaction is suggested according to which the potential free energy of sorption of substrate group R on the enzyme is 2 ΔGtrans(R). Such a high gain in the free energy of hydrophobic interaction may only be realized if (a) in the free enzyme the sorption region has a thermodynamically unfavorable contact with the aqueous medium, and (b) water is forced out of the active center as a result of the hydrophobic interaction of substrate group R with the enzyme. Such a model is in agreement with the published x-ray data on the structure of the crystalline enzyme.The kinetic experiment has proved that not all the potential free energy of sorption is realized as binding force. Thus the true free energy of the binding of substrate group R with the protein does not exceed half the maximum value, both in the enzyme-substrate complex and acylenzyme.
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  • 200
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A step perturbation (concentration-jump or solvent-jump) relaxation method is described for studying the rates of fast reactions, using nontransient observation in a steadystate flow system. Therelaxation time is determined from a single measurement of an integrated relaxation amplitude. Remeasurement of the rate of dimerization of aqueous rhodamine B is reported.
    Additional Material: 3 Ill.
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