摘要:

AbstractStarting from Smoluchowski's hypothesis, a simple algorithm is developed in order to obtain the apparent rate constant at large values of time,t, with some physical and chemical processes, as in the case of diffusion controlled reactions. Some practical examples are illustrated, assuming nonuniform distribution function, space‐dependent diffusion coefficient or short‐range interaction leading to an asymptotic analytical expression of the form α + β/√t, where α and β are constants function of the system of

ISSN:0538-8066    

DOI:10.1002/kin.550210502

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe kinetics of oxidation of aliphatic amines viz., ethylamine,n‐butylamine, isopropylamine (primary amines), diethylamine (secondary amine), and triethylamine (tertiary amine) by chloramine‐T have been studied in NaOH medium catalyzed by osmium (VIII) and in perchloric acid medium with ruthenium(III) as catalyst. The order of reaction in [Chloramine‐T] is always found to be unity. A zero order dependence of rate with respect to each [OH−] and [Amine]has been observed during the osmium(VIII) catalyzed oxidation of diethylamine and triethylamine while a retarding effect of [OH−] or [Amine]on the rate of oxidation is observed in case of osmium(VIII) catalyzed oxidation of primary aliphatic amines. The ruthenium(III) catalyzed oxidation of amines follow almost similar kinetics. The order of reactions in [Amine] or [Acid]decreases from unity at higher amine or acid concentrations.The rate of oxidation is proportional to {k′ andk″ [Ruthenium(III)] or [Osmium(VIII)]} wherek′ andk″ (having different values in case of ruthenium(III) and osmium(VIII)) are the rate constants for uncatalyzed and catalyzed path respectively. The suitable mechanism consisting with the kinetic data is proposed in each c

ISSN:0538-8066    

DOI:10.1002/kin.550210503

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe following reactions:were studied over the temperature ranges 533–687 K, 563–663 K, and 503–613 K for the forward reactions respectively and over 683–763 K, for the back reaction. Arrhenius parameters for chlorine atom transfer were determined relative to the combination of the attacking radicals. The ΔHr°(1) = −3.95 ± 0.45 kcal mol−1was calculated and from this value the ΔH∮(C2F5Cl) = −2.66.3 ± 2.5 kcal mol−1and D(C2F5‐Cl) = 82.0 ± 1.2 kcal mol−1were obtained. Besides, the ΔHr°(2) was estimated leading to D(CF2ClCF2Cl) = 79.2 ± 5 Kcal mol−1. The bond dissociation energies and the heat of formation are compared with those of the literature. The effect of the halogen substitutents as well as the importance of the polar effects for halogen

ISSN:0538-8066    

DOI:10.1002/kin.550210504

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractN‐chloro‐3‐aminopropanol was obtained in aqueous solution by mixing the amine with the hypochlorite. The first order decomposition kinetics of theN‐chloramine in strongly alkaline media are explained by a mechanism in which the rate controlling step is the formation of an imine which is subsequently hydrolyzed. Spectrophotometry of the reaction in acid media showed that under these conditions dichloramines are formed: the second order experimental kinetics of this process are explained by a mechanism in which the rate‐controlling step is a reaction between the protonated and free forms of theN

ISSN:0538-8066    

DOI:10.1002/kin.550210505

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractUsing a relative rate method, rate constants have been determined at 296 ± 2 K for the gas‐phase reactions of the OH radical with toluene, the xylenes, and the trimethylbenzenes. Using the recommended literature rate constant for the reaction of OH radicals with propene of (2.66 ± 0.40) × 10−11cm3molecule−1s−1, the following rate constants (in units of 10−12cm3molecule−1s−1) were obtained: toluene, 5.48 ± 0.84;o‐xylene, 12.2 ± 1.9;m‐xylene, 23.0 ± 3.5;p‐xylene, 13.0 ± 2.0; 1,2,3‐trimethylbenzene, 32.7 ± 5.3; 1,2,4‐trimethylbenzene, 32.5 ± 5.0; and 1,3,5‐trimethylbenzene, 57.5 ± 9.2. These data are

ISSN:0538-8066    

DOI:10.1002/kin.550210506

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe elimination kinetics of 2‐chloropropionic acid have been studied over the temperature range of 320–370.2°C and pressure range of 79–218.5 torr. The reaction in seasoned vessel and in the presence of the free radical suppressor cyclohexene, is homogeneous, unimolecular, and obeys a first‐order rate law. The dehydrochlorination products are acetaldehyde and carbon monoxide. The rate coefficient is expressed by the following Arrhenius equation: logk1(s−1) = (12.53 ± 0.43) – (186.9 ± 5.1) kJ mol−1(2.303RT)−1. The hydrogen atom of the carboxylic COOH appears to assist readily the leaving chloride ion in the transition state, suggesting an intimate ion pair mechanism operatin

ISSN:0538-8066    

DOI:10.1002/kin.550210507

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550210501

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY