摘要:

AbstractBy allowing thet‐butoxy radical to decompose in the presence of nitric oxide, it has been possible to determine rate constants for decomposition by the measurements of the relative rates (2) and (3)Process (3) is clearly pressure dependent. The value ofk3(∞) has been determined in the presence of several inert gases (CF4, SF6, N2, and Ar) and a value ofk3interpolated for atmospheric conditions. The results may be compared with those for other relevant alkoxy radicals at room temperature. Extrapolated values fork3in the presence of CF4lead to the result\documentclass{article}\pagestyle{empty}\begin{document}$$ k_3 (\infty)/s^{ - 1} = 10^{14.6 \pm 0.6} \exp (- 8052 \pm 604/T) $$\end{docum

ISSN:0538-8066    

DOI:10.1002/kin.550190502

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractDisproportionation‐combination rate constant ratios,kd/kc, have been determined for R + RCH2CHCl and for the auto disproportionation‐combination of RCH2CHCl radicals, R = CF3, C2F5, and C3F7. Thekd/kcfor R = CF3and to a lesser degree for R = C2F5and C3F7were very sensitive to the surface/volume ratio of the reaction vessel suggesting a heterogeneous component for disproportionat

ISSN:0538-8066    

DOI:10.1002/kin.550190503

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe aqueous cleavage of methyl salicylate has been studied in the buffer solutions of various primary mono‐ and di‐amines as well as secondary amines at 30°C. Both ionized (MS−) and nonionized (MSH) methyl salicylate are reactive toward primary mono‐ and di‐amines. The second‐order rate constants for the reactions of MS−with primary mono‐ and di‐amines of pKa>9.4 exhibit Bronsted plot of slope (βnuc) of 0.82. This high value of βnucis attributed to an intramolecular proton transfer in a thermodynamically unfavorable direction in the rate‐determining step in a stepwise process for the formation of monoanionic tetrahedral intermediate. However, a concerted process for the formation of a monoanionic tetrahedral intermediate in the reactions of MS−with amine nucleophiles wherein expulsion of leaving group is a rate‐determining step is not completely ruled out. The α‐effect nitrogen nucleophiles hydroxylamine and hydrazine reveal, respectively, ca. 104‐ and 103‐fold higher reactivity compared to other amine nucleophiles of comparable basicity. The value of βnucof 1.03 obtained for the reactions of primary monoamines with MSH is ascribed to the expulsion of leaving group as the rate‐determining step. The significantly lower value of βnucof 0.60 obtained in the reactions of MSH with both monoprotonated and unprotonated diamines is explained in terms of possible occurrence of intramolecular general acid‐base catalysis. Intramolecular general base catalysis is responsible for the enhanced nucleophilic reactivity of primary amines toward MS−. Dimethylamine, piperidine, morpholine, and piperazine have no dete

ISSN:0538-8066    

DOI:10.1002/kin.550190504

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractA new approach is presented for analyzing kinetic models of relaxation‐type oscillatory systems on the basis of numerical data. Feature sensitivities of the length of the two kinetic states of the Belousov‐Zhabotinsky (BZ) reaction with respect to the rate constants of the model are explained by means of a logic‐based inference system. The main kinetic roles of the individual reaction steps on the relaxing components are revealed, and a consistent interpretation of the kinetic states is given by this process. Both the high and the low set of rate constants were studied. According to our analysis, the bromous acid‐hypobromous acid reaction is an important Br−producing step of the model, and in the case of the low set, the bromate‐bromous acid reaction is not the rate‐determining step of the bromous acid

ISSN:0538-8066    

DOI:10.1002/kin.550190505

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractA chemical kinetic reaction mechanism has been developed which describes the oxidation of propanal within the temperature range 400–700 K. This mechanism has been tested against data obtained by four experimental groups over a wide range of initial conditions. The induction period and the absolute rate of propanal consumption are predicted to within a factor of 2 for initial densities of oxygen and propanal ranging over factors of 400. The existence and location of the negative temperature coefficient in the consumption of propanal are also simulated properly. The yields of all major and most minor products are predicted to within a factor of 2 for the wide variety of initial conditions tested. Sensitivity analyses were carried out at 553 and 713 K to identify the reactions primarily responsible for controlling the rate of propanal consumption and the distribution of product

ISSN:0538-8066    

DOI:10.1002/kin.550190506

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550190507

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550190501

出版商:John Wiley&Sons, Inc.    

年代:1987

数据来源: WILEY