238. Mechanism of substitution at a saturated carbon atom. Part LVI. Kinetics of the reaction of triphenylmethyl chloride with methyl alcohol in benzene

Abstract

Bateman, Cooper, and Hughes, J., 1940, 930 (electrophilic catalysis by HC1 of alltyl chloride reactions in aprotic solvents) ; Part LIII, Hughes. Ingold, Patai, and Pocker, 1967, 1206 (stability Qf ClHClion in benzene, the reason for the catalysis).

Perchlorate catalysis of the methanolysis of triphenylmethyl chloride in benzene solution and its relation to special salt effects in solvolysis reactions

“…dependence of (ktPc -kto0) on the perchlorate 1 ) = Ar concentration is determined at extremely low I + , alkylammonium chloride concentration; say P' 2 x M, it will be identical to that found by Hughes et al (6) showed that the catalyzed Hughes et al (6), since the plots are essentially rate constant (klpO -kloO) is proportional topi, horizontal at this point. However, at 10 x indicating that the catalysis was brought about M chloride, log,, (ktPc -kloO) plotted against by e simple perchlorate ion.…”

“…The results of Hughes et al (6) have been extended in a detailed kinetic study of the suppression of the perchlorate catalysis by common-ion salt. These workers fitted this effect to the equation where the superscripts refer to the rate constants in the presence of a concentration of perchlorate (p) and chloride (c), and p is a competition factor between the chloride and other competitors for the carbonium ion-pair.…”

“…The study of the nucleophilic substitution reactions of triphenylmethyl chloride in benzene solvent by Swain and co-workers and by the Hughes-Ingold school led to controversy over the mechanism of the reaction (1)(2)(3)(4)(5)(6)(7)(8). After the correction of experimental errors on the part of both groups, the mechanisms presented by them were essentially the same, even though the statements differed in detail (3, 8).…”

“…Part of the investigation made by Hughes et al on the methanolysis of triphenylmethyl chloride concerned the catalysis of the reaction by saline perchlorate and the suppression of this catalysis by the common-ion chloride salt (6). The catalyzed reaction was found to have a kinetic order of one half with respect to the tetra-nbutylammonium perchlorate catalyst, which was interpreted to mean that the catalysis was brought about by single perchlorate ions.…”

“…Winstein prefers to explain this catalysis as an interaction involving the perchlorate ion-pair alone and has carried out a kinetic analysis to prove this (15). This paper included a criticism of Ingold's interpretation of the behavior of triphenylmethyl chloride in benzene, particularly with respect to the application of the steady state approximation to the mechanistic schemes proposed by Ingold et al It is stated that a common-ion retardation of the methanolysis rate as observed by Hughes et al (6) is not to be expected on the basis of the steady state approximation. However, the common-ion retardation was confirmed by Leffek and Waterfield (9) and the experimental behavior was fitted to an equation derived by use of the steady state approximation, from a mechanism which is essentially the same as that of Hughes …”