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  • 1985-1989
  • 1980-1984  (186)
  • 1920-1924
  • 1982  (186)
  • Physical Chemistry  (126)
  • Life Sciences (general)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 327-349 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Observations are reported of the effect of the buffer gases He, Ne, and CF4, in the pressure range of 0-30 torr, on the branching ratio [HCl]/[DCl] of the unimolecular decomposition The ratio R = kH/kD has been measured in high-pressure thermal decomposition (670-1100 K) and was shown to give a unique measure of the internal energy of the decomposing molecules and hence, with RRKM theory and pressure fall-off data, a time scale for their decomposition.Applying the thermal data to the photolysis leads to the conclusion that excitation and decomposition are produced by the laser spike (high intensity, 70 ns FWHM) and also at a slower rate by the larger, less intense tail (1.6 μs). Added buffer gases quench the latter, leaving the former which, from measurements of R, is shown to correspond to excitations of 115 ± 15 kcal/mol and lifetimes of ∼30 ps. No bond breaking is seen despite the high energies, in accord with theoretical expectations. The results require an enhanced rate of photon absorption by the highly excited molecules, which are about hundredfold greater than that observed for 300 K molecules. Data are also reported for C2H2F2 and the secondary multiphoton photolysis of the ethylenes produced. Effects of beam geometry and wavelength are explored.
    Additional Material: 12 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 371-379 
    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 of ground-state oxygen atoms with methanol has been determined between 297 and 544 K by a phase-shift technique using mercury photosensitized decomposition of N2O to generate oxygen atoms. The relative oxygen atom concentration was monitored by the chemiluminescence from the reaction of oxygen atoms with nitric oxide. The results are accommodated by the Arrhenius expression k1 = (9.79 ± 2.71) × 1012 exp[(-2267 ± 111)/T]cm3/mol·s, where the indicated uncertainties are 95% confidence limits for 10 degrees of freedom. As an incidental part of this work, the third-body efficiency of CH3OH relative to N2O for the reaction O + NO + M → NO2 + M (M = CH3OH) was determined to be 3.1 at 298 K.
    Additional Material: 3 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 435-438 
    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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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 417-434 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The flash photolysis resonance fluorescence technique was used to measure the rate constants of the reaction O + O2 + M → O3 + M (M = N2, O2, Ar, and He) as a function of temperature. The results for the rate constants are given by The activation energies with N2, O2, and Ar as third bodies are equal within the experimental error, (-1370 → 340 cal/mol), and the relative third-body efficiencies at 298 K for N2, O2, Ar, and He are 1.00, 0.99, 0.69, and 0.60, respectively.
    Additional Material: 8 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 439-445 
    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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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 447-450 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 647-657 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the gas-phase thermal reaction between CF2(OF)2 and CO has been studied in a static system at temperatures ranging between 110 and 140°C. The only reaction products were CF2O and CO2, giving the following stoichiometry: \documentclass{article}\pagestyle{empty}\begin{document}$${\rm CF}_{\rm 2} {\rm (OF)}_{\rm 2} {\rm + 2CO = 2CF}_{\rm 2} {\rm O + CO}_{\rm 2} {\rm}\Delta n{\rm = 0}$$\end{document} The reaction is homogeneous. The rate is strictly second order in CF2(OF)2 and CO, and is not affected by the total pressure or by the presence of reaction products. Oxygen promotes a sensitized oxidation of CO and inhibits the formation of CF2O.The experimental results in the absence of oxygen can be explained by a chain mechanism similar to that proposed for the reaction between F2O and CO with an overall rate constant of \documentclass{article}\pagestyle{empty}\begin{document}$$k_1 = 1.45 \times 10^9 {\rm exp}(- 20,900/RT)L/mol \cdot s$$\end{document} From the experimental data obtained on the oxygen-inhibited reaction, the rate constant for the primary process can be calculated: \documentclass{article}\pagestyle{empty}\begin{document}$$\begin{array}{*{20}c} {({\rm I})} \quad {{\rm CF}_{\rm 2} ({\rm OF)}_{\rm 2} + {\rm CO} \to {\rm CF}_{\rm 2} (\mathop {\rm O}\limits^{\rm .}){\rm OF} + {\rm F}\mathop {\rm C}\limits^{\rm .} {\rm O}} \quad\quad {k_1 = 1.45 \times 10^9 {\rm exp}(- 20,900/RT)L/mol \cdot s} \\\end{array}$$\end{document} The chain length v = 2.5 is independent of the temperature. Taking for collision diameters σCF2(OF)2 = 6 Å and σCO = 3.74 Å, a value α = 5.3 × 10-3 for the steric factor is obtained.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 669-677 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title reaction has been investigated in the temperature range of 490-573 K. Initial reactant pressures were varied in the range of 0.2-5.2 torr (I2) and 2-20 torr (C6H5SiH3). The rate of iodine consumption, monitored spectrophotometrically, was found to obey \documentclass{article}\pagestyle{empty}\begin{document}$$ - \frac{{d[{\rm I}_{\rm 2}]}}{{dt}} = \frac{{k_{3/2} [{\rm I}_{\rm 2}]^{{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace} \!\lower0.7ex\hbox{$2$}}} [{\rm C}_{\rm 6} {\rm H}_{\rm 5} {\rm SiH}_{\rm 3}]}}{{1 + k'[HI]/[I_2]}}$$\end{document} both by initial rate and integrated equation fitting procedures. The effect of added initial HI conformed to this expression. The data are consistent with a conventional I-atom propagated chain reaction, and for the step \documentclass{article}\pagestyle{empty}\begin{document}$${\rm I}^{\rm .} + {\rm C}_{\rm 6} {\rm H}_{\rm 5} {\rm SiH}_{\rm 3} \to {\rm C}_{\rm 6} {\rm H}_{\rm 5} \mathop {\rm S}\limits^{\rm .} {\rm iH}_{\rm 2} + {\rm HI}$$\end{document} the rate constant is given by \documentclass{article}\pagestyle{empty}\begin{document}$${\rm log}k_1 (dm^3 /mol \cdot s) = (11.52 \pm 0.08) - (76.8 \pm 0.8{\rm kJ/mol})/RT{\rm ln}10$$\end{document} From this is derived the bond dissociation energy value C6H5SiH2—H = 374 kJ/mol(88 kcal/mol). A comparison with other Si—H dissociation energy values indicates that the “silabenzyl” stabilization energy is small, ≈7 kJ/mol.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 699-710 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diethylhydroxylamine, (C2H5)2NOH, was oxidized by NO2 at 25°C in a long-path-length infrared gas cell. The measured products of the reaction were HONO and CH3CHO. The reaction scheme which explains the reaction is was oxidized by NO2, and the reaction was found to be very rapid with k1 〉 10-16 cm3/s. The products of the reaction were verified by both infrared absorption (CH3CHO, C2H5NO) and gas chromatography (CH3CHO, NO).
    Additional Material: 3 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 789-799 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rates of oxidation of phenylthioacetic acid (PTAA) and several substituted phenylthioacetic acids by potassium peroxodiphosphate (PP) in 50% (v/v) aqueous acetic acid have been studied in detail. The rate of oxidation is expressed as \documentclass{article}\pagestyle{empty}\begin{document}$$\frac{{- d[{\rm PP]}}}{{{\rm dt}}} = k[{\rm PP][PTAA][H}^{\rm +}]$$\end{document}An analysis of the dependence of the rate on [H+] reveals that H3P2O8- is the active oxidizing species in the oxidation. The effect of ring substituents on the rate gives a ρ+ value of -0.45 ± 0.03 (r = 0.998, s = 0.02 at 40°C), pointing to the development of an electron-deficient center in the transition state. The results are discussed in terms of a mechanism involving the rate-determining formation of an intermediate between PP and phenylthioacetic acids, followed by the decomposition of the intermediate. These kinetic results are compared with those obtained in the oxidation of phenylthioacetic acids by peroxodisulfate.
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  • 11
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 801-811 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A kinetic study on the oxidation of V(IV) by chloramine-T (CAT) at pH 6.85 by N-bromo succinimide (NBS) in aqueous acetic acid-perchloric acid media and by N-iodo succinimide (NIS) in aqueous perchloric acid medium has been carried out. In all the systems studied the order with respect to the oxidant is unity. NBS and CAT oxidation reactions exhibited Michaelis-Menten type kinetics, and the NIS study indicated unit dependence on [substrate]. Independence on acidity has been observed in the case of CAT and NBS reactions, but NIS reactions exhibited inverse unit dependence on [acid]. Novel solvent influences have been noticed in the case of CAT reactions, but with NIS and NBS reactions retardation in the rate has been observed with an increase in the percentage of acetic acid. Plausible mechanisms consistent with the results have been postulated, and suitable rate laws in consonance with the postulated mechanisms have been derived.
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  • 12
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 813-814 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 13
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982) 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 14
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 815-821 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The experimental behavior of the cerium- and manganese-catalyzed Belousov Zhabotinskii oscillating reaction with ethyl acetoacetate as organic substrate has been investigated. Under certain conditions the system displays two types of temporal oscillations. Damped highfrequency oscillations appear immediately after the addition of potassium bromate solution to complete the reaction mixture. These high-frequency oscillations may be regarded as being superimposed on an induction period of the type found in the reaction using malonic acid. After the induction period, low-frequency oscillations of the normal type are obtained. Both the high-frequency and the low-frequency oscillations can be monitored with a platinum redox or with a bromide specific ion electrode.
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  • 15
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 839-847 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Relative rate constants for the reaction of OH radicals with a series of ketones have been determined at 299 ± 2 K, using methyl nitrite photolysis in air as a source of hydroxyl radicals. Using a rate constant for the reaction of OH radicals with cyclohexane of 7.57 × 10-12 cm3 molecule-1 s-1, the rate constants obtained are (× 1012 cm3 molecule-1 s-1): 2-pentanone, 4.74 ± 0.14; 3-pentanone, 1.85 ± 0.34; 2-hexanone, 9.16 ± 0.61; 3-hexanone, 6.96 ± 0.29; 2,4-dimethyl-3-pentanone, 5.43 ± 0.41; 4-methyl-2-pentanone, 14.5 ± 0.7; and 2,6-dimethyl-4-heptanone, 27.7 ± 1.5. These rate constants indicate that while the carbonyl group decreases the reactivity of C—H bonds in the α position toward reaction with the OH radical, it enhances the reactivity in the β position.
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  • 16
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A kinetic spectrophotometric investigation of the reaction of the hydrogen peroxide anion with methyl p-nitrophenyl sulfate in methanol solvent resulted in the evaluation of the pKa of HOOH in methanol at 25°C as 15.8 ± 0.2. Since normal kinetic procedures for the determination of the equilibrium constant K for the process CH3O- + H2O2 ⇄ CH3OH + HO2- were found to be associated with high uncertainty, another procedure was devised to establish the magnitude of K. This method is based on an analysis of the changing slopes of plots of pseudo-first-order rate constants against the total base concentration as the stoichiometric amount of hydrogen peroxide is varied. The method is applicable to any system in which anionic nucleophiles generated in situ compete with solvent anions. Such a corroboration of kinetically determined equilibrium constants is believed essential. The kinetic data allow the specific rate constant kHOO-for the reaction of methyl p-nitrophenyl sulfate with hydrogen peroxide anions to be evaluated and yield the rate constant ratio kHOO-/kMeO- = 8.8 ± 2.2. This confirms the existence of an α effect at saturated carbon in this system.
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  • 17
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 849-859 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rate law for the demetallation of the title indium(III)-porphin complex in aqueous acidic thiocyanate media at 3.00M ionic strength was found to be of the form \documentclass{article}\pagestyle{empty}\begin{document}$$+ \frac{{d{\rm [H}_{\rm 4} {\rm P}^{{\rm 2} - } {\rm]}}}{{dt}} = \frac{{ab[{\rm H}^{\rm + }]^2 [{\rm NCS}^ -]^2 }}{{1 + b[{\rm H}^{\rm + }]^2 }}[{\rm InP]}_{\rm t}$$\end{document} where [H4P2-] is the concentration of the diacid product formed, [InP]t is the total concentration of all forms of indium(III)-porphin complex present, and a and b are constants. The constant a is a pseudo-third-order rate constant with the value (0.057 ± 0.005)M-2 s-1 and b has the value 0.704M-2 at 50.5°C. If the mechanism for demetallation involves ringpuckering with the attachment of two H+ ions, then 1/b can be identified with the product K1K2 for the stepwise dissociation of two protons from two ring pyrrolic nitrogen atoms of H2InP-. In the sulfonated tetraphenylporphin used for these studies the ring pyrrolic nitrogen atoms seem to be the most probable sites for protonation. If this identification is correct, the value of 1.42 ± 0.13 found for the product K1K2 shows the enormous effect that the presence of the In3+ center has on the ionization constants of these two protons. That the kinetic studies show saturation effects with respect to proton addition to InP3- may result from the fact that In3+ sits about 0.6 Å above the porphin ring.
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  • 18
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 893-902 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of cleavage of 3-hydroxybicyclo[4.2.0]octa-1,3,5-trien-7-ones in aqueous sodium hydroxide, and of the alkoxy and acetoxy analogues in methanolic sodium methoxide solution, were examined under pseudo-first-order reaction conditions. The dependence of the rate upon the basicity of the solvent, whether measured by H- or by [OR-], reflects the possible structure of the transition state. The deduced mechanism is also supported by the effects of substituents upon the reaction rate. The relative amounts of the volatile reaction products derived from o-toluic acid and from phenylacetic acid are understood in terms of the substituent effect upon the relative stabilities of the carbanions.
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  • 19
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 875-891 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The isomerization reaction of cholest-5-en-3-one has been studied in a solution of cyclohexane using trichloroacetic acid as catalyst. At the same time a general reaction scheme is proposed to be valid for all the cases assayed in which the monomer form of the acid is considered as the only effective catalyst. The experimental results agree with these hypotheses and with the calculation of the individual rate constant together with the reaction order with respect to the catalyst. Semiquantitative studies have been carried out with other catalysts and solvents, confirming the validity of the reaction scheme. The thermodynamic activation parameters have also been calculated, and a comparative study was made with the results of the evaluation of the reaction when it takes place in amphiprotic solvents. A reaction mechanism is proposed based on all the kinetic information obtained.
    Additional Material: 6 Ill.
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  • 20
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 903-917 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Kinetics of the basic hydrolysis of 1-glyceryl mononitrate (1-MNG) and 2-glyceryl mononitrate (2-MNG) were investigated in CO2-free aqueous calcium hydroxide solutions. The hydrolysis reactions were carried out in a temperature-controlled reactor vessel with provision for continuous N2 sparging of the reaction mixture. Both glyceryl nitrate esters hydrolyzed via second-order reaction at 25°C. 2-MNG in calcium hydroxide solution isomerized to 1-MNG, which subsequently hydrolyzed to form NO3-. In strongly basic aqueous solutions of NaOH (30%), 2-MNG is converted to glycidol and NO3-.
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  • 21
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 919-926 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Relative rate constants for the gas-phase reactions of OH radicals with a series of alkyl nitrates have been determined at 299 ± 2 K, using methyl nitrite photolysis in air as a source of OH radicals. Using a rate constant for the reaction of OH radicals with cyclohexane of 7.57 × 10-12 cm3/molec·s, the rate constants obtained are (× 1012 cm3/molec·s): 2-propyl nitrate, 0.18 ± 0.05; 1-butyl nitrate, 1.42 ± 0.11; 2-butyl nitrate, 0.69 ± 0.10; 2-pentyl nitrate, 1.87 ± 0.12; 3-pentyl nitrate, 1.13 ± 0.20; 2-hexyl nitrate, 3.19 ± 0.16; 3-hexyl nitrate, 2.72 ± 0.22; 3-heptyl nitrate, 3.72 ± 0.43; and 3-octyl nitrate, 3.91 ± 0.80. These rate constants, which are the first reported for the alkyl nitrates, are significantly lower than those for the parent alkanes, and a formula, based on the numbers of the various types of C—H bonds in the alkyl nitrates, is derived for rate constant estimation purposes.
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  • 22
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 933-944 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The literature results for the pyrolysis of bis trifluoromethyl peroxide are reexamined and compared with those for dimethyl peroxide. The thermochemistry yields the result that the π-bond energy in carbonyl fluoride is 96 ± 10 kcal/mol compared to 74 kcal/mol for that in formaldehyde. Thermodynamic additivity contributions are derived for the C—(F)3(O) and O—(C)(F) groups. Some conclusions are drawn in relation to the oxidation of halogeno methyl radicals and the chemistry of the atmosphere.
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  • 23
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 927-932 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aqueous iodination of trans-2-butenoic acid proceeds via hydrolysis of I2 to form HOI and I-, then rapid addition of HOI across the double bond to form the iodohydrin product. In the presence of iodate to keep iodide concentration low, the reaction proceeds at a conveniently measurable rate. The rate for the addition reaction \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm HOI + CH}_{\rm 3} {\rm CH=\!=CHCOOH} \to {\rm CH}_{\rm 3} {\rm CH(OH)CHICOOH}$$ \end{document} is -d[C4H6O2]/dt = 5900 [H+][C4H6O2][HOI]M/s at 25.0°C when [IO3-] = 0.025M and ionic strength = 0.3. The overall rate law in the presence of iodate is \documentclass{article}\pagestyle{empty}\begin{document}$$ -d[{\rm I}_{\rm 2}]/dt = 3.2 \times 10^{ - 3} \times 10^{ - 3} [{\rm H}^{\rm + }][{\rm IO}_{\rm 3}^ -]^{0.65} [{\rm C}_{\rm 4} {\rm H}_{\rm 6} {\rm O}_{\rm 2}]^{1/2} [{\rm I}_{\rm 2}]^{1/2} M/{\rm s}$$ \end{document} where [H+] and [IO3-] are total concentrations used to prepare the solution.
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  • 24
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 945-952 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of gas-phase decomposition of methyl isocyanate have been investigated in the range of 427-548°C. Two decomposition routes are followed; the predominant one is a radical-chain process giving CO, H2, and HCN as major products, which has an order of 1.5 and an Arrhenius equation given by log k(L1/2/mol1/2·s) = (13.12 ± 0.06) - (56,450 ± 1670) cal/mol/2.303 RT. The minor route is the bimolecular formation of N,N′-dimethylcarbodiimide and CO2, which from the low activation parameters Ea = 31.6 kcal, A = 105.30 L1/2/mol1/2·s, and the reaction order of 1.57 appears to be heterogeneous.
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  • 25
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982) 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 26
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 977-984 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyridiniumchlorochromate (PCC) oxidizes aniline and substituted anilines except nitro anilines smoothly in chlorobenzene-nitrobenzene mixtures in the presence of dichloroacetic acid. The reaction has unit dependence on each of the aniline, PCC, and dichloroacetic acid concentrations. Electron-releasing substituents accelerate the reaction, whereas electronwithdrawing groups retard the reaction, and the rate data obey Hammett's relationship. The reaction constant ρ is -3.75. Azobenzene and p-benzoquinone have been obtained as products. The observed experimental data have been rationalized in terms of the formation of an intermediate complex involving PCC-amine undergoing a rapid decomposition to products.
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  • 27
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    International Journal of Chemical Kinetics 14 (1982), S. 1007-1015 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of stabilized carbonium ions of setoglaucin, methyl violet, and ethyl violet with cyanide ions are largely catalyzed by the cationic micelles of cetyltrimethylammonium bromide (CTAB) in aqueous media. Added counterions (anions in this case) have strong inhibitory effects on the CTAB-catalyzed reactions in the following order: N3- 〉 NO3- 〉 Br- 〉 Cl- 〉 F- 〉 no salt. The inhibitory effects of the counterions have been attributed to the exchange between added anions and reagent (CN-) in the micellar media. The data have been analyzed by the model schemes, and mathematical formulations were developed. Various parameters associated with the exchange process, such as equilibrium exchange constant, number of surfactant molecules per substrate molecule, number of added anions, and a factor related to the binding of additives to the catalytic micellar aggregates, have been evaluated.
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  • 28
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics and mechanism of oxidation of iminodiacetic acid and N-methyliminodiacetic acid by aquasilver(II) and Ag(II)-2,2′-bipyridine complexes has been investigated. The results are discussed with reference to the active reaction pathways, the equilibrium quotient of the title reactions, the protolytic equilibria which involve the oxidizing complex, and the intrinsic self-exchange rates of the oxidants.
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  • 29
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    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 399-416 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Recent experimental results on the thermal decomposition of N2O5 in N2 are evaluated in terms of unimolecular rate theory. A theoretically consistent set of fall-off curves is constructed which allows to identify experimental errors or misinterpretations. Limiting rate constants k0 = [N2] 2.2 × 10-3 (T/300)-4.4 exp(-11,080/T) cm3/molec·s over the range of 220-300 K, k∞ = 9.7 × 1014 (T/300)+0.1 exp(-11,080/T) s-1 over the range of 220-300 K, and broadening factors of the fall-off curve Fcent = exp(-T/250) + exp(-1050/T) over the range of 220-520 K have been derived. NO2 + NO3 recombination rate constants over the range of 200-300 K are krec,0 = [N2] 3.7 × 10-30 (T/300)-4.1 cm6/molec2·s and krec,∞ = 1.6 × 10-12 (T/300)+0.2 cm3/molec·s.
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  • 30
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    International Journal of Chemical Kinetics 14 (1982), S. 381-397 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the gas-phase elimination of several chloroesters were determined in a static system over the temperature range of 410-490°C and the pressure range of 47-236 torr. The reactions in seasoned vessels, and in the presence of a free-radical inhibitor, are homogeneous, unimolecular, and follow a first-order law. The temperature dependence of the rate coefficients is given by the following Arrhenius equations: for methyl 3-chloropropionate, log k1(s-1) = (13.22 ± 0.07) - (231.5 ± 1.0) kJ/mol/2.303RT; for methyl 4-chlorobutyrate, log k1(s-1) = (13.31 ± 0.25) - (221.5 ± 3.4) kJ/mol/2.303RT; and for methyl 5-chlorovalerate, log k1(s-1) = (13.12 ± 0.25) - (221.7 ± 3.2) kJ/mol/2.303RT. Rate enhancements and lactone formation reveal the participation of carbonyl oxygen of the carbomethoxy group. The order COOCH3-5 〉 COOCH3-6 〉 COOCH3-4 in assistance is similar to the sequence of group participation in solvolysis reactions. The partial rates for the parallel eliminations to normal dehydrohalogenation products and lactones have been estimated and reported. The present results lead us to consider that an intimate ion-pair mechanism through participation of the carbomethoxy group may well be operating in some of these reactions.
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  • 31
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    International Journal of Chemical Kinetics 14 (1982), S. 517-534 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Many experiments in chemical kinetics are initiated by a fast pulse, such as electric discharge, shock wave, flash lamp, or laser. After this pulse one observes the production and subsequent decay of a reactive intermediate. One then postulates a mechanism and adjusts the associated rate constants so as to minimize the difference between the results of the experiment and the prediction of the mechanism. The parameters to be estimated are usually strongly correlated, so that it is not possible to determine them separately. These estimated parameters are of little value unless we can also estimate statistically valid confidence limits for them. The difficulties are discussed which frequently arise in estimating parameters and confidence limits for a kinetic mechanism which is widely used in interpreting laser excitation and fluorescence measurements, that is, first-order production and decay. These difficulties, and methods for dealing with them, are illustrated with realistic data. The estimation problem is particularly ill conditioned when the production and loss rates are nearly equal. In some experimental systems this can be avoided, but in others it is inevitable.
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  • 32
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    International Journal of Chemical Kinetics 14 (1982), S. 535-541 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is proposed whereby the orders and rate constants for processes obeying the rate law -dA/dt = kAn may be determined. The method is illustrated in two ways. First, simulated data for processes of various orders are treated, and the treatment is shown to be capable of reproducing orders and rate constants to a high degree of accuracy. The factors affecting the accuracy with which n and k can be determined are considered. These are inaccuracy in the determination of concentration values, irregularity of the time intevals between concentration determinations, and the length of those time intervals. It is shown that if concentrations are determined at times that are close together, the effect of the other two factors is small, but if the time intervals are made longer, the errors due to the other two factors affect the calculated values of n and k much more seriously. Second, the method was applied to two homogeneous reactions, of which one was first-order and one was second order, and three heterogeneous reactions, of which one was found by the original workers to be first order, one to be zero order, and one to vary between zero and first order, depending on the initial pressure. The present method gives results in agreement with these conclusions and reproduces the rate constants to within ±5% in all cases.
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  • 33
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    International Journal of Chemical Kinetics 14 (1982), S. 565-583 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Results are reported from moderated nuclear recoil 18F experiments with the 273 K CHF3/C3F6/C2F6 system. Although the measurement sensitivity is only about ±12%, there is no evidence to support the occurrence of nonthermal F-to-HF reactions at 95 mol % C2F6 moderator concentration.
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  • 34
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    International Journal of Chemical Kinetics 14 (1982), S. 543-564 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The main difference between the simple RRK theory and the better based but more complex RRKM theory is explained. Starting from the premise that the classical versus quantum mechanical estimation of the density of states is the major source of the difference, earlier attempts to incorporate the quantum effects in an effective value for the number of oscillators s are noted. By examining the expression for the RRKM rate coefficient it is found that a single effective s value will generally not suffice, but a much better representation of the quantum effects can be obtained if it is recognized that the problem inherently contains two different effective s values. A theory based on this analysis is constructed. It reproduces RRKM results to much improved accuracy, removing difficulties found earlier with single-s-value theories.
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  • 35
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    International Journal of Chemical Kinetics 14 (1982), S. 613-621 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal unimolecular decomposition of pent-2-yne has been studied over the temperature range of 988-1234 K using the technique of very low-pressure pyrolysis (VLPP). The main reaction pathway is C4—C5 bond fission producing the resonance-stabilized 3-methylpropargyl radical. There is a concurrent process producing molecular hydrogen and penta-1,2,4-triene presumably via the intermediate formation of cis-penta-1,3-diene. The 1,4-hydrogen elimination from cis-penta-1,3-diene is the rate-determining step in the molecular pathway. This is supported by an independent VLPP study of cis- and trans-penta-1,3-diene. RRKM calculations show that the experimental rate constants for C—C bond fission are consistent with the following high-pressure rate expression at 1100 K: \documentclass{article}\pagestyle{empty}\begin{document}$$\log k_1 = \left({s^{ - 1}} \right) = \left({16.0 \pm 0.3} \right) - \left({72.6 \pm 2.0} \right)/\theta $$\end{document} where θ = 2.303RT kcal/mol and the A factor was assigned from the results of shock-tube studies of related alkynes. The activation energy leads to ΔHf,3000[CH3C≡CĊH2] = 70.3 and DH3000[CH3CCCH2—H] = 87.4 kcal/mol. The resonance stabilization energy of the 3-methylpropargyl radical is 10.6 ± 2.5 kcal/mol, which is consistent with previous results for this and other propargylic radicals.
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  • 36
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An iterative method has been devised for the simulation of chemiluminescence data during the oxidative decomposition of αα′ azobisisobutyronitrile in the presence of ethylbenzene. From this simulation the cross termination rate constant of the two types of peroxy radicals present has been estimated.
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  • 37
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    International Journal of Chemical Kinetics 14 (1982), S. 659-668 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of gamma-radiation-induced free-radical reactions in carbon tetrachloride solutions of ethanol and n-pentanol were studied in the range of 0.05-0.80M and 25-170°C. The rate constant for the reaction \documentclass{article}\pagestyle{empty}\begin{document}$${\rm CCl}_{\rm 3} + {\rm R} - CH_2 - {\rm OH}\mathop \to \limits^{k1} {\rm CHCl}_{\rm 3} + {\rm R} - {\rm CH} - {\rm OH}$$\end{document} was found as \documentclass{article}\pagestyle{empty}\begin{document}$$k1(M^{- 1} \cdot s^{- 1}) = 10^{8.6 \pm 0.4} \exp - (\frac{{9900 \pm 600{\rm cal}}}{{RT}})$$\end{document} The activation energy is larger by 0.8 kcal/mol than for secondary alcohols, while the A1 factors are about the same.
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  • 38
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    International Journal of Chemical Kinetics 14 (1982), S. 955-975 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dark-phase experiments between isoprene and O3 are discussed. UNC outdoor chamber experiments have shown that in high-concentration systems of isoprene and O3 (5 ppm C and 1 ppm) approximately 75% of the reacted carbon can be observed in the product formation of HCHO, CO, methacrolein, methylvinylketone, methylglyoxal, acetaldehyde, and propylene. Mechanisms were developed which gave reasonable fits to dark-phase chamber experiments of MACR, MVK, isoprene, and O3. Experimental data and modeling results were used to generate O3 rates of attack on MVK and MACR. An isoprene-O3 rate of 1.67 × 10-2 ppm-1·min-1 was used and is consistent with other rates reported in the literature. Dark isoprene-O3 systems appear to form homogeneously nucleated aerosol. Most of these particles appear and remain at diameters well below the optical cutoff region (0.3-0.5 μm), as opposed to the particles from similar α-pinene-O3 systems, which also form at smaller sizes but then grow into the optical size range (0.5 μm). Lower concentrations of α-pinene and O3 (0.2 ppm C and 0.12 ppm) still generated substantial aerosol, but by comparison, rapid CN nucleation was not observed during a similar side-by-side system of isoprene and O3.
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  • 39
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    International Journal of Chemical Kinetics 14 (1982), S. 985-996 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Time-resolved absorption spectra for a reaction mixture of p-methoxystyrene and tetracyanoethylene (TCNE) are found to have a band maximum at 325 nm which is assigned to the 1,4-cycloadduct. The reaction in chloroform at 15, 20, and 25°C is followed by the charge-transfer band at 600 nm. The 1,4-cycloadduct, besides the so far known 1,2-cycloadduct and EDA complex, is taken into account to derive the rate equation for the EDA complex that is a linear second-order differential equation. The rate constants for the elementary steps involved in the reaction are obtained. The 1,4-cycloaddition has an activation entropy of -63 J/K·mol for the cycloreversion and a reaction constant ρ of -4.7, both of which indicate the polar transition state. On the other hand, activation entropy of the 1,2-cycloaddition is 73 J/K·mol more negative than that of the 1,4-cycloaddition, supporting the zwitterionic mechanism for the 1,2-cycloaddition.
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  • 40
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    International Journal of Chemical Kinetics 14 (1982), S. 997-1005 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of acetylene (A) with cyclohexa-1,3-diene (CHD) has been studied between 450 and 592 K. The pressures of A ranged from 25 to 112 torr and those of CHD from 8 to 62 torr. The reaction yields only ethene (E) and benzene (B) instead of bicyclo[2.2.2]octa-2,5-diene (BOD), the product that is expected for a 1,4,1′,2′ addition of the Diels-Alder type. It is first order with respect to each reagent. The rate constant (in L/mol·s) is given by \documentclass{article}\pagestyle{empty}\begin{document}$$\log _{10} k = - (27,150 \pm 120)/4.576T + (7.49 \pm 0.05)$$\end{document} The thermal decomposition of BOD has also been studied. In the ranges of 354-435 K and 0.5-6 torr, the reaction is first order and results in the formation of equal amounts of B and E as the reaction of A with CHD does. Its rate constant (in s-1) is given by \documentclass{article}\pagestyle{empty}\begin{document}$$\log _{10} k_d = - (32,520 \pm 40)/4.576T + (14.06 \pm 0.02)$$\end{document} The following consecutive reactions are proposed for the reaction between A and CHD: where BOD is the primary product that is too unstable to be detected. This implies that the rate constant k is equal to ka. The reaction mechanisms and the strain energy in BOD are discussed.
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  • 41
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    International Journal of Chemical Kinetics 14 (1982), S. 1105-1112 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Energetic hydrogen atoms generated by photolysis of HBr or HI react with CDCl3 by abstracting either a deuterium atom (1) or a chlorine atom (2): The integral probability of reaction (2) has been measured for several defined initial translational energies of H*, and the phenomenological threshold energy is 31 ± 14 kJ/mol. For initial translational energies in the range of 66-121 kJ/mol, the ratio of the integral probabilities of Cl abstraction and of D abstraction, when normalized to equal numbers of Cl and D atoms, is 2.4 ± 0.3. The interpretation of the integral reaction probabilities in terms of the excitation functions of reactions (1) and (2) is discussed. Measurements of the moderating effect of CO2 on reactions (1) and (2) show that CDCl3 is slightly more effective than CO2 as a moderator of H atoms in the energy range of 90-30 kJ/mol.
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  • 42
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    International Journal of Chemical Kinetics 14 (1982), S. 1165-1182 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Results are reported from moderated nuclear recoil 18F experiments with the CH4/C3F6/C2F6 mixture system. At a 99.5% confidence level measurement precision of ±3.4%, non-thermal F-to-HF reactions are phenomenologically suppressed at C2F6 moderator concentrations in the range of 95.0-99.95 mol-%. Effectively equilibrium reaction conditions can be established in well-designed experiments of this type.
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  • 43
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    International Journal of Chemical Kinetics 14 (1982), S. 1199-1209 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction 2NO2 + ROH = RONO + HNO3 (R = CH3 or C2H5) has been studied using the FTIR method at reactant pressures from 0.1 to 1.0 torr at 25°C. The termolecular rate constant for the forward reaction was determined to be (5.7 ± 0.6) × 10-37 cm6/molec2·s for CH3OH and (5.7 ± 0.8) × 10-37 cm6/molec2·s for C2H5OH, that is, d[RONO]/dt = k[NO2]2[ROH]. The corresponding equilibrium constants were measured as 1.36 ± 0.06 and 0.550 ± 0.025 torr-1, respectively. These results are consistent with those of a previous study based on the NO2 decay measurements at reactant pressures from 1 to 10 torr.
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  • 44
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    International Journal of Chemical Kinetics 14 (1982), S. 1183-1197 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of oxidation of arginine, histidine, and threonine by chloramine-T (CAT) have been investigated in alkaline medium at 35°C. The rates are first order in both [CAT] and [amino acid] and inverse fractional order in [OH-] for arginine and histidine. The rate is independent of [OH-] for threonine. Variation of ionic strength and addition of the reaction product, p-toluenesulfonamide, or Cl- ions had no effect on the rate. A decrease of the dielectric constant of the medium by adding methanol decreased the rate with arginine, while the rates increased with histidine and threonine. The solvent isotope effect was studied using D2O. (kobs)D2O/(kobs)H2O was found to be 0.55 and 0.79 for arginine and histidine, respectively. The reactions were studied at different temperatures, and activation parameters have been computed. The oxidation process in alkaline medium, under conditions employed in the present investigations, has been shown to proceed via two paths, one involving the interaction of RNHCl (formed rapidly from RNCl-), with the amino acid in a slow step to form monochloroamino acid, which subsequently interacts with another molecule of RNHCl in a fast step to give the products, p-toluenesulfonamide (RNH2), and the corresponding nitrile of the amino acid (R'CN). The other path involves the interaction of RNCl- with the amino acid in a similar way to give RNH2 and R'CN. Mechanisms proposed and the derived rate laws are consistent with the observed kinetics. The rate constants predicted using the derived rate laws, as [OH-] varies, are in excellent agreement with the observed rate constants, thus justifying these rate laws and hence the proposed mechanistic schemes.
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  • 45
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    International Journal of Chemical Kinetics 14 (1982), S. 1211-1218 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rates of oxidation of XCOO- (X = H, D) by Br2 in acid aqueous media were measured between 274 and 332 K. The derived Arrhenius parameters for both reactions \documentclass{article}\pagestyle{empty}\begin{document}$$\log k_{\rm H} (M^{- 1} {\rm s}^{{\rm - 1}}) = (11.18 \pm 0.10) - (14.33 \pm 0.13)/\theta $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$\log k_{\rm D} (M^{- 1} {\rm s}^{{\rm - 1}}) = (13.77 \pm 0.13) - (17.62 \pm 0.04)/\theta $$\end{document} where θ = 4.575T × 10-3 kcal/mol, with (kH/kD)298K = 2.85, reveal a primary isotope effect, but the difference (ED - EH) = 3.29 kcal/mol and the ratio AD/AH = 91 fall beyond the limits imposed by semiclassical transition-state theory, suggesting tunneling or a multiple-stage mechanism. However, it can be shown that either tunneling in a single step or a three-step, internal return mechanism can be ruled out as alternative models, since both require unreasonable kinetic parameters to fit the data. The simplest scheme accounting for the present observations involves tunneling in the decomposition of a charge transfer complex in equilibrium with the reactants.
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  • 46
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    International Journal of Chemical Kinetics 14 (1982), S. 1219-1229 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Kinetic investigations on the reaction between U(IV) and H2O2 have been carried out at different acidities in chloride medium at an ionic strength of 2M. The observed bimolecular rate constant has been found to be dependant on [H+]-1.3. The activation energy of the overall reaction has been found to vary from 13.4 ± 0.7 to 18.0 ± 0.8 kcal/mol in the range of acidity from 0.3 to 1.5M. The results have been explained on the basis of three parallel rate-controlling reactions involving unhydrolyzed species of U(IV) and hydrolyzed species UCl(OH)2+ and UO2+. The values of the rate constants for these three reaction paths have been found to be of the order of 3.95, 5.59 × 103, and 1.49 × 105M-1 min-1, respectively.
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  • 47
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    International Journal of Chemical Kinetics 14 (1982) 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 48
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    International Journal of Chemical Kinetics 14 (1982), S. 623-629 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal unimolecular reactions of cis- and trans-penta-1,3-diene (c-PTD and t-PTD) have been studied over the temperature range of 1002-1235 K using the technique of very low-pressure pyrolysis (VLPP). c-PTD decomposes via 1,4-hydrogen elimination analogous to that previously reported for cis-but-2-ene. RRKM calculations incorporating a six-center transition state show that the experimental rate constants are consistent with the following high-pressure rate expression at 1100 K: \documentclass{article}\pagestyle{empty}\begin{document}$$\log k_\infty = \left({s^{ - 1}} \right) = \left({13.0 \pm 0.6} \right) - \left({64.5 \pm 2.0} \right)/\theta $$\end{document} where θ = 2.303RT kcal/mol, and the A factor was assumed to be the same as that for cis-but-2-ene. The activation energy is in excellent agreement with that obtained for cis-but-2-ene. t-PTD also undergoes decomposition by H2 elimination presumably via the prior rapid isomerization to c-PTD the results are in exact agreement with those for c-PTD.
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  • 49
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    International Journal of Chemical Kinetics 14 (1982), S. 631-639 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of Rh(III) catalyzed oxidative cleavage of styrene, stilbene, and phenylacetylene by periodate have been investigated in the presence of HClO4 in aqueous acetic acid medium. The kinetic orders are completely dependent on the nature of unsaturation. In the cases of styrene and stilbene the reactions are first order in the oxidant and Rh(III), zero order with respect to the substrate, and independent of [H+], whereas in the case of phenyl acetylene the reaction is zero order with respect to the oxidant and first order with respect to the substrate and Rh(III). The reaction is independent of [H+] in the range of 0.01-0.05M studied. A mechanism involving higher Rh(V) species has been postulated in the case of styrene as well as stilbene, and metal ion catalyzed hydration has been postulated in case of phenylacetylene. The influence of the solvent has been investigated, and a comparative analysis of the kinetic orders of styrene and stilbene is made with those of phenylacetylene.
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  • 50
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    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982) 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 51
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Far-infrared rotational transitions in ClO(X2∏3/2, υ = 0) have been observed using laser magnetic resonance (LMR) with an optically pumped spectrometer. Five observed transitions at wavelengths between 444 and 713 µm have been compared with values predicted with spectroscopic constants from the literature. LMR detection of ClO has been used to study its reactions with NO and NO2 in a discharge flow system under pseudo-first-order conditions for ClO. The measured rate constants are k(ClO + NO) = (7.1 ± 1.4) × 10-12 exp[(270 ± 50)/T] cm3/molec·s for the temperature range of 202 〈 T 〈 393 K; k(ClO + NO2 + M) = (2.8 ± 0.6) × 10-33 exp[(1090 ± 80)/T] cm6/molec2·s (M = He, 250 〈 T 〈 387 K), (3.5 ± 0.6) × 10-33 exp[(1180 ± 80)/T] (M = O2, 250 〈 T 〈 416 K), and (2.09 ± 0.3) × 10-31 (M = N2, T = 297 K). All measurements were made at low pressures, between 0.6 and 6.6 torr. These results are compared with those from other studies.
    Additional Material: 10 Ill.
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  • 52
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    International Journal of Chemical Kinetics 14 (1982), S. 735-738 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An inorganic compound, NaH2PO2, has been found to generate temporal chemical oscillations in Belousov-Zhabotinskii type reactions when it is substituted for the organic reducing material. Gaseous products were removed by a constant flow of nitrogen carrier gas. Periodic Br2 evolution was measured polarographically.
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  • 53
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    International Journal of Chemical Kinetics 14 (1982), S. 739-747 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the gas-phase decomposition of methyl trifluoroacetate and 2,2,2-trifluoroethyl trifluoroacetate, two esters without β hydrogen atoms, have been investigated, and a comparative study was carried out on methyl acetate. All these compounds are thermally much more stable than fluorinated esters with β hydrogens, decomposing at temperatures some 150°C above the latter by a completely different mechanism involving partly heterogeneous radical chains. The marked difference in behavior between the two types of fluorinated ester confirms that none of them decomposes by hydrogen fluoride elimination, but that those with β hydrogen atoms follow the normal ester decomposition route. The fluorinated esters examined here decompose in a manner generally similar to methyl acetate, but the presence of fluorine in the molecule brings about an extreme sensitivity to surface conditions.
    Additional Material: 3 Ill.
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  • 54
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    International Journal of Chemical Kinetics 14 (1982), S. 749-759 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oscillatory phenomenon was observed in aqueous solution during the oxidation of ascorbic acid by oxygen. Even though the exact number and amplitude of the oscillations could not be exactly duplicated for each and every run, such factors as temperature, concentration of ascorbic acid, cupric ions, and pH affecting the oscillatory behavior were studied, and those regions where oscillations occurred were delineated. A mechanism consistent with the oscillatory behavior is proposed and discussed.
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  • 55
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    International Journal of Chemical Kinetics 14 (1982), S. 761-780 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermal cracking of indan and tetralin in the gas phase was carried out in a flow reactor at 500°C and 8 MPa pressure in the presence of hydrogen and nitrogen. The primary reactions are ring cracking and dehydrogenation, regardless of the nature of the second component. Ring cracking, however, is strongly enhanced by the presence of hydrogen. This enhancement becomes less significant with increasing concentration of the hydrocarbon in the gaseous reaction mixture and also with a decreasing ratio of hydrogen to hydrocarbon. At hydrocarbon concentrations larger than approximately 0.5 g·mol/L and H2-to-HC molar ratios of 1 or lower, conversion rates are almost equal in hydrogen and in nitrogen. Ring cracking exhibits different kinetic behavior in nitrogen than in excess of hydrogen. This illustrates the occurrence of two complementary cracking mechanisms, each of which can dominate in certain concentration ranges. The H2-initiated ring cracking is gradually transformed into a hydrogen-donor mechanism as the leading reaction scheme when the concentration of indan or tetralin is increased.
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  • 56
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    International Journal of Chemical Kinetics 14 (1982), S. 781-788 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Relative rate constants for the reaction of OH radicals with a series of n-alkanes have been determined at 299 ± 2 K, using methyl nitrite photolysis in air as a source of OH radicals. Using a rate constant for the reaction of OH radicals with n-butane of 2.58 × 10-12 cm3 molecule-1s-1, the rate constants obtained are (X1012 cm3 molecule-1 s-1): propane 1.22 ± 0.05, n-pentane 4.13 ± 0.08, n-heptane 7.30 ± 0.17, n-octane 9.01 ± 0.19, n-nonane 10.7 ± 0.4, and n-decane 11.4 ± 0.6. The data for propane, n-pentane, and n-octane are in good agreement with literature values, while those for n-heptane, n-nonane, and n-decane are reported for the first time. These data show that the rate constant per secondary C - H bond is ∽40% higher for  - CH2 -  groups bonded to two other  - CH2 -  groups than for those bonded to a  - CH2 -  group and a  - CH3 group.
    Additional Material: 4 Ill.
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  • 57
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    International Journal of Chemical Kinetics 14 (1982), S. 1071-1103 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: While environmental chamber data have been widely used to generate and validate computer models of the chemistry occurring in polluted atmospheres, the effects of the chambers on the gas-phase chemistry being studied have been poorly characterized. In order to investigate such chamber effects, a series of NOx - air irradiations, with trace levels of organics present to monitor OH radical concentrations, have been carried out in four different environmental chambers (ranging in volume from ∼100 to 40,000 L) at varying temperatures, humidities, pressures, and reaction conditions. In addition, a number of control experiments have been carried out to validate the technique for measuring OH radical levels in these irradiations. The data show that unknown sources of OH radicals are present in all of the chambers studied. The data are consistent with the presence of two distinct radical sources: (1) the photolysis of initially present HONO, whose importance increases with increasing NO2/NO concentration ratios, but which is a minor contributor to the overall radical flux after 30-60 min of irradiation, and (2) a constant (for these NOx - air irradiations) radical source which dominates beyond approximately the first 60 min of irradiation. The radical input rates, after the first ∽30-60 min of irradiation, are independent of the NO concentration, increase with increasing temperature, humidity, and NO2 concentration, are proportional to light intensity, and are dependent on the chamber employed. Although the exact nature of this radical source is still undetermined, results of experiments reported here allow a number of possible mechanisms to be ruled, out, and these are discussed.
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  • 58
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    International Journal of Chemical Kinetics 14 (1982), S. 1113-1124 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oxidation of halotoluenes by hexacyanoferrate(III) in aqueous acetic acid containing perchloric acid (0.5M) at 50°C gave the corresponding aldehyde as the major product, and a small amount of polymeric material. The order with respect to each of the reactants - substrate, oxidant, and acid - was found to be unity. Increasing proportions of acetic acid increased the rate of the reaction. The reaction was influenced by changes in temperature, and the activation parameters have been evaluated. The Hammett plot yielded a ρ+ value of -1.8. A kinetic isotope effect kH/kD = 6.0 has been observed. The pathway for the conversion of the halotoluenes to the products has been mechanistically visualized as proceeding through the benzylic radical intermediate, formed in the rate-determining step of the reaction. The radical undergoes rapid conversion to the products.
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  • 59
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    International Journal of Chemical Kinetics 14 (1982) 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 60
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    International Journal of Chemical Kinetics 14 (1982), S. 1125-1138 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The flash photolyses of azo-n-propane and azoisopropane in the presence of oxygen have been studied by kinetic spectroscopy. The transient absorption spectra observed in the region of 210-290 nm are assigned to the n-propylperoxy and isopropylperoxy radicals. For the n-propylperoxy radical, εmax = 1148 ± 29 L/mol cm at 242.5 nm and for the isopropylperoxy radical, εmax = 1273 ± 75 L/mol cm at 240 nm. The rate constants for the mutual reactions (7) 2RO2· → products were measured to be k7 = (2.0 ± 0.2) X 108 L/mol s for the n-propylperoxy radical and k7 = (7.8 ± 2.2) X 105 L/mol s for the isopropylperoxy radical.
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  • 61
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    Acta Biotechnologica 2 (1982), S. 42-42 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 62
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    Acta Biotechnologica 2 (1982), S. 51-58 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper considers techniques of measurement of the curves of oxygen consumption by microorganisms. The widely applied method of obtaining the value of the critical oxygen concentration (COC) using these curves has been analysed. The experimental conditions necessary for the adequate measurement of the culture respiration rate in a fermenter have been found. It has been shown that in the case when the respiration rate within the considered range of pO2 is determined by one and the same enzyme, the COC value is not an apropriate characteristic of the mode of the respiration rate dependence on oxygen concentration.
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  • 63
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    Acta Biotechnologica 2 (1982), S. 192-192 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 64
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    Acta Biotechnologica 2 (1982), S. 187-191 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Rabbit liver microsomal cytochrome P-450 was immobilized by entrapment in calcium alginate gel. Aminopyrine demethylation experiments showed that the immobilized enzyme system is highly active and exhibits an unimpaired functional stability as compared with crude microsomes. The alginate entrapped microsomes were employed in a fixed bed recirculation reactor, where aminopyrine was continuously demethylated. Such model enzyme reactor can be a useful tool for studying extracorporeal drug detoxification or preparative substrate conversion with microsomal enzyme systems.
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  • 65
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    Acta Biotechnologica 2 (1982) 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 66
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The zone reader of the Autoselect-system enables to measure the 64 inhibition zones of a quadratic bioassay plate with an accuracy of 0,1 mm within 3 minutes. A carriage moves each zone in the light beam. With a special photometrical device 3 defined areas of the inhibition zone can be measured quantitatively by 2 receivers. The indicated values of the diameters result from the analog treatment of the signals. By coupling to a computer the datas of the measuring and other desired informations are printed out.
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  • 67
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    Acta Biotechnologica 2 (1982), S. 199-204 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The advantages of the Autoselect-system are explained. They are offered by a higher speed of all manipulations, by a significantly better accuracy, by getting more informations and by easier physical labour. In the most cases the automated work can be done in a fourth till a tenth of the time needed for manual handlings. The capacity of the machines amounts 5 000 to 30 000 colonies/samples per day. Special problems as well as possibilities for a further increase of the efficiency are discussed.
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  • 68
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The Supreme Court of the US in 1980 granted a patent for a strain of Pseudomonas containing two plasmides after genetic manipulation. This is the first case of patenting a living organism. Whereas the patent law of US and of many other countries further more on supports the principle that natural products are not patentable man-made microorganisms on the other hand fullfil very important crucials of patentability as far as they are new, unobvious, reproducible and useful. The situation arising as the result of this decision is described and the implications and consequenses for the patent law, the taxonomy and the general biological thought are discussed.
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  • 69
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    Acta Biotechnologica 2 (1982), S. 226-226 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 70
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    Acta Biotechnologica 2 (1982), S. 213-225 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of assimilation of hydrocarbons having a different structure by Candida yeasts was studied.The rates of oxidation of various carbon atoms in the molecules of isoalkanes, alkylaromatic hydrocarbons and n-alkanes were evaluated in the range of C11 to C28.Metabolic inhomogeneity of carbon atoms in the molecules of isolakanes and alkylaromatic hydrocarbons was observed. A competition in the assimilation of the called hydrocarbons and n-alkanes and also a competition in the assimilation of n-alkanes of a different molecular weight, i.e. metabolic inhomogeneity of carbon atoms of n-dodecane and n-tetracosane was found out for yeasts.
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  • 71
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Understanding both the qualitative and quantitative transient responses to inlet flow and substrate step functions has been a relatively unsolved problem for continuous fermentation processes. This study of transient responses and simple descriptive models suggests that the saturation constant of the MONOD equation is a variable. Thatf variable depends on the rate constants of parallel biochemical pathways leading to cell growth, the concentration of cells themselves, and the concentration of all products in the culture. Mechanisms for describing the hysteresis behavior of the growth rate funcion are postulated in terms of the underlying molecular biology of the microbial system.
    Additional Material: 13 Ill.
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  • 72
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    Acta Biotechnologica 2 (1982), S. 239-249 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: For several years now, we can notice efforts in increasing the efficiency of microbial processes by means of more intensive scientific investigation of such processes. Essential prerequisites to it are improved possibilities for process monitoring (available sensors) as well as facilities for realtime processing of process information. In this paper a microcomputer system is represented, which has been constructed on the base of computing needs for fermentation. The computing needs for fermentation experiments are outlined and the structure of the microcomputer is described. As an example it is illustrated what tasks can be solved by this microcomputer in coupled operation with a laboratory fermentor.
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  • 73
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 74
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    Acta Biotechnologica 2 (1982), S. 251-262 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The industrial continuous fermentation for the production of microbial protein is like any real process subject to disturbances. The considerable social expenditures involved in production make it necessary to restrict the negative consequences of these disturbances to a minimum by means of suitable measures. One such measure is the computer-aided adaptation of the static optimum. For the reaction on nonmeasurable disturbing inputs an algorithm is given containing the steps data filtering, adaption of process model and optimization, and the solution of the data-filtering problem in the widest sense by spline functions is discussed. The application of this algorithm to a specific problem of process control is demonstrated in [1].
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  • 75
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    Acta Biotechnologica 2 (1982), S. 263-274 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The influence of technological variables on the cell disintegration of yeast suspensions by means of a ball mill and a high pressure homogenizer has been studied by measuring the electrical conductivity. The rate constants and half-life periods are calculated. Regarding the production of protein isolates, the stipulation of optimal disintegration conditions requires a compromise between a degree of disruption as high as possible and a low destruction of the cell walls.By homogenizing, fragments of cell walls arise which are more uniform and better separable in comparison with the milling process. Therefore the mechanical breakage of yeast cells on a large scale should be carried out by the use of high pressure homogenizers.
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  • 76
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    Acta Biotechnologica 2 (1982), S. 297-298 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 77
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Starting from cotton linters cellulose modified in physical structure type of lattice, degree of order, state of swelling by different pretreatments, and from culture filtrates of Gliocladium spec., the initial stage of enzymatic hydrolysis of cellulose has been investigated. Especially with substrates of high degradability a considerable effect of stirring on rate of formation of soluble products was found. For linerization of yield-vs-time-curves (% residue resp. 7percnt; solubles as a criterion for yield), a 2-parameatric first order rate law was found to be suitable within a limited time interval, values of k1 were higher and for the accessible part of the substrate were lower in the initial stage of hydrolysis than in the later one. The MICHAELIS-MENTEN-constant kM has been determined for substrates of different physical structure after different times of reaction. Data found for kM indicated a stronger dependence of kM on reaction time than on physical structure of the substrate under conditions applied.
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  • 78
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    Acta Biotechnologica 2 (1982), S. 299-302 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The empirical determined constant of 3.14 gram biomass per available electron is a good base for the calculation of minimum substrate consumption coefficients in the aerobic fermentation of paraffins by yeasts.The analysis of experimental determined specific substrate consumption coefficients and their comparison with the corresponding theoretical values show that the theoretical ones can be reached only if the substrate composition referring to carbon and hydrogen is of optimal composition for all syntheses.
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  • 79
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    Acta Biotechnologica 2 (1982) 
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  • 80
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  • 81
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  • 82
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    Acta Biotechnologica 2 (1982), S. 369-375 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The biotin activity of beet and lactose molasses against the test strain Saccharomyces cerevisiae 225 by auxanographic method was evaluated. The level of lactose molasses biotin activity is almost twice as high as that obtained in the case of beet molasses. The results of bioautography with test strains Saccharomyces cerevisiae 225 and Lactobacillus arabinosus 17-5 indicate the qualitative composition of biotin derivatives (vitamers) in both molasses. Depending on the various technological steps e.g. sterilization or clarification one may find differences in the content and qualitative composition of biotin vitamers.
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  • 83
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    Acta Biotechnologica 2 (1982) 
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    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 84
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    Acta Biotechnologica 2 (1982), S. 3-41 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: In this review the state of the art in animal cell technology, using suspension culture techniques is updated as far as the end of 1980. We have tried to discuss, on a broad basis, the current status and potential developments of both, the purely biological and the biochemical engineering aspects which may be important to improve the performance and design of animal cell technologies. The process economics could be considerably improved by the use of transformed animal cell substrates, the use of cheaper cultivation media and by methodological and engineering means. Most of these aspects are in the state of realization. Nevertheless, for a great variety of biological active substances which do not require so - or posttranslational processing, recombinant DNA-techniques (e.g. genetic engineering) are a promising alternative for the production of animal cell derived substances.
    Additional Material: 10 Ill.
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  • 85
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 2 (1982), S. 72-72 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 86
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 2 (1982), S. 78-78 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 87
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 88
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 2 (1982), S. 87-94 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: An enzyme being able to hydrolize the imido linkage at the N-terminal end of proline is isolated from E. coli B. This fact corresponds to the specifity of hydrolization of the animal prolidase. Enzyme synthesis within the cells of E. coli B is carried out independently from growth. Changed environmental factors may influence the formation rate of enzyme in a restricted way. A relatively high enzyme biosynthesis can be reached by cultivating the strain E. coli B at a temperature of 37°C as well as an initial pH-value of the medium of 7.0 in submerged culture (400-500 rpm) By variation of the medium composition enzyme synthesis does not change considerably, however, biomass yield can be increased about 100% If mechanical cell desintegration is optimized by means of ultrasonic or vibration homogenisator the cell components may be easily released with a higher proline specific activity as animal prolidase.
    Additional Material: 6 Ill.
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  • 89
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 2 (1982), S. 114-114 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 90
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 2 (1982), S. 115-115 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 91
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 2 (1982), S. 116-116 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 92
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Catabolic pathways of long-chain n-alkanes in the range of C8 to C18 are demonstrated and results of investigation about the regulation of monoterminal oxidation are given: - Enzymes of monoterminal alkane oxidation usually are inducible- Several intermediates of alkane oxidation can inhibit the primary oxidation of concerned alkane-Substances, e.g. glucose and glycerol, which ordinary don't be developed in catabolic alkane reactions, in many cases have an inhibitory effect on alkane oxidationThe regulation of catabolic pathways has a great influence on the formation of specific products This influence is demonstrated examplarily at the production of biotin, fatty acids and citric acid.
    Additional Material: 6 Ill.
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  • 93
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Most mathematical models for describing the physiological state in fermentations lead to solutions of the so-called “stiff differential systems” during simulation on a digital computerThere is no suitable conventional software for solving these systemsAs a result of a relatively extensive screening of suitable methods for the solution of “stiff” differential systems (about 200 methods) it may be concluded that the semiimplicit RUNGE-KUTTA-formulas of the ROSENBROCK type, which constitute a part of the collection of programmes STIFFSOLVER-80, are optimal for the simulation of fermentation processesFor determining kinetic parameters from integral data the authors use the system of programmes BIOKINTheir practical application is discussed for 3 examples: 1Growth of the yeast Saccharomyces cerevisiae and changes in the content of specific compounds (proteins and ergosterol)2Quantitative evaluation of “;direct oxygen transfer” in the submerged culture.3Biosynthesis of a new antibiotic substance mucidin.
    Additional Material: 3 Ill.
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  • 94
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 2 (1982), S. 178-178 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 95
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 2 (1982), S. 179-185 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The enzymatic hydrolysis of cellobiose, an important intermediate of the decomposition of cellulose containing materials, with immobilized β-glucosidase preparations from Geotrichium candidum, Trichoderma lignorum and Aspergillus foetidus was examinedAt first it was the aim to prepare from differently purified samples with different specific cellobiase activities high active preparations on the basis of the inorganic carrier Silochrom S-80. Characteristics e.g. thermal stability and temperature and pH optimum of immobilized preparations were compared with those of soluble preparationsKinetics of cellobiose hydrolysis by immobilized enzyme preparations were studied.
    Additional Material: 5 Ill.
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  • 96
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 2 (1982), S. 43-50 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Floc formation, especially the influence of floe diameter variations on the total velocity of the process, was investigated in aerobic growth processes of yeast on the hydrocarbons of crude oil.The experimental results show that the diameter of the flocs is a function of the rheological properties of the fluids and the flow conditions.The floc diameter varies between 0,1 mm and a few millimeters. About 90% of the total yeast cells are situated in the interior of the flocs.Since oxygen must be transferred to all yeast cells their oxygen supply was studied.Thus, the yeast cells in the floc interior were not sufficiently supplied with oxygen, if the floc diameter reached a critical value.In such cases a decrease of the biomass formation rate was observed, although the dissolved oxygen concentration of the aquaeous fermentation medium was greater than zero. Therefore, aerobic microbial growth processes in multicomponent systems must be carried out without floc formation or under such conditions as cause very small floc diameters.
    Additional Material: 4 Ill.
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  • 97
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 2 (1982), S. 59-71 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: There are described possibilities of scale up in stirred tank fermenters being based on known relations of mass-, energy-and heat transfer. The represented mathematical description shows the problems of the necessary scale up in the practice with the theory of similarity in the stirred tank fermenter. Relating on the method of RUSHTON for calculation of the energy capacity in different stirred fermenters the influence of the aeration is examined and confirmed with experimental results of the author. By the sysem of equations the known parameters of the aerobic fermenters can be calculated.
    Additional Material: 5 Ill.
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  • 98
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 2 (1982), S. 73-77 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The aim of the technological treatment of microbial processes is the optimal working of the production plant. The treatment itself is to be seen as a process whose realization requires a certain amount of expenditure. The problem of optimization of this process can with certain restictions be approximately solved in a series of steps. After a general formulation of the problem explanations are given for two important and typical steps - the determination of the extend of modelling and the choice of production cultures.
    Type of Medium: Electronic Resource
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  • 99
    Electronic Resource
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 2 (1982), S. 79-85 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: L-lysine synthesis pathway enzyme activities: β-aspartate kinase (EC.2.7.2.4), diaminopimelate decarboxylase (EC.4.1.1.20) for two L-lysine producing strains Brevibacterium flavum 22LD and RC-115 were studied. It has been found that β-aspartate kinase and diaminopimelate decarboxylase in the Br. flavum RC-115 are less sensitive to feed-back inhibition by lysine and threonine. It is supposed that desensitized β-aspartate kinase in the Br. flavum RC-115 can be determined by genetical changes of the regulatory properties of the β-aspartate kinase.Auxotrophity in the locus of homoserine dehydrogenase was tested and no homoserine dehydrogenase (EC.1.1.1.3) activity was found in either strain.The combination of these both types of mutation supplemented by the lack of catabolic repression in the RC-115 strain makes it an active lysine producer in the medium with high carbohydrates content.
    Additional Material: 3 Ill.
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  • 100
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Growing conditions have been found out for the bacterium Arthrobacter GJM-I to produce a lytic enzyme system, which converts cells of the yeast Candida spec. H to protoplasts quickly and in a good yield. Estimating the activities of α-mannanase and β-glucanase we found out the optimal culture time to gain the lytic enzyme system from the culture filtrate. It was shown that radioactive labeling of the yeast cells makes it possible to estimate quantitatively the conversion to protoplasts and the simultaneous lysis. The obtained lytic enzyme system can substitute the snail cnzyme system which was used for cell conversion of Candida spec. H to protoplasts till now.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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