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

Abstract

The kinetic form of the suppression of the perchlorate catalysis of the methanolysis of triphenylmethyl chloride in benzene solvent by tetra-n-butylammonium chloride has been investigated. This is consistent with a catalysis brought about by a simple perchlorate ion, suppressed by a competition between such ions and alkylammonium chloride ion-pairs for the alkyl halide ion-pair.The results are discussed in relation to the qualitatively similar special salt effects observed in acetolysis reactions by Winstein and co-workers, with particular reference to the necessity of the concept of intimate and solvent-separated ion-pairs in the interpretation of these effects.

Living cationic polymerization of isobutyl vinyl ether, 1. Initiation by hydrogen iodide/tetraalkylammonium salts

“…The fact that the values of the obtained slopes of In kapp vs. In ([TBAPJ) are close to unity, indicates that mainly ion pairs are responsible for the catalytic activity of tetraalkylammonium salts in the polymerization reaction 14).…”

Electrofugalities of Acceptor‐Substituted Tritylium Ions

“…Common ion rate depression is a well‐known phenomenon5h,5i,11 that has recently been studied systematically in solvolyses of benzhydryl chlorides 12,13. It was shown that the determination of the ionization rate constants ( k ion ) can be simplified by addition of large amounts of amines, which rapidly trap the generated benzhydrylium ions and suppress the return of chloride ions (Scheme ) 12a.…”

The Kinetics of the Ethanolysis Reaction of Some 4-Nitro-substituted Triphenylmethyl Chlorides

“…This compound reacts via a carbonium ion mechanism even under conditions adverse to the ionization process. Thus in a benzene solution, which is colorless, the second-order reactions observed are in fact bimolecular attacks of the reagent on the triphenylmethyl chloride carbonium ion-pair (2)(3)(4)(5)(6)(7)(8)(9)(10)(11). In order to observe an S,2 reaction the substrate molecule must have its ionizing capability reduced by electron-withdrawing substituents on the phenyl rings.…”