A kinetic investigation of the effects of molecular complexing on the acidities of some π donor carboxylic acids

Autor:	Allan K. Colter, R. James Kersting
Rok vydání:	1977
Předmět:	Reaction rate chemistry.chemical_compound Ethanol Reaction rate constant Chemistry Organic Chemistry Inorganic chemistry General Chemistry Kinetic energy Acceptor Catalysis
Zdroj:	Canadian Journal of Chemistry. 55:1028-1038
ISSN:	1480-3291 0008-4042
DOI:	10.1139/v77-144
Popis:	Rates of reaction of the five π donor acids indole-3-acrylic acid (IAA), indole-5-carboxylic acid (ICA), 3,4,5-trimethoxybenzoic acid (TMBA), 2,4-dihydroxybenzoic acid (DHBA), and 3,4,5-trihydroxybenzoic acid (THBA) with 4-chlorodiphenyldiazomethane (4-ClDDM) in ethanol at 30 °C were measured in the presence of the π acceptors 1,3,5-trinitrobenzene (TNB), benzotrifuroxan (BTF), and 1,2,4,5-tetracyanobenzene (TCNB) and in the absence of acceptor. For 12 of the 13combinations studied, added acceptor produced rate enhancements. The rate data were combined with independently-determined 1:1 acceptor – donor acid association constants to obtain second-order rate constants for reaction of the 1:1 acceptor – donor acid complexes. From the increase in the rate constant resulting from complexation, estimates of the increase in Ka(H2O, 25 °C) produced by complexation were obtained for 13 acceptor – donor acid combinations. Second-order rate constants for reaction of 4-ClDDM with 10 other carboxylic acids and p-toluenesulfonic acid in ethanol at 30°C were also measured and the pattern of reactivity shown to parallel very closely that of diphenyldiazomethane.
Databáze:	OpenAIRE
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