Some salt effects on the reactions of 4-fluoro- and chloro-nitrobenzenes with trimethylamine in dimethyl sulphoxide

Abstract

The influence of lithium, potassium, and tetra-n-butylammonium perchlorates and of lithium and trimethylammonium chlorides on the title reactions has been studied. Increasing concentrations of all the salts have little effect on the rate of reaction of the chloro-substrate, but the rate for 4-fluoronitrobenzene shows a strong, curvilinear dependence on the concentration of lithium and trimethylammonium Ions. The results are interpreted in terms of a rate-determining electrophilically catalysed decomposition of the reaction intermediate formed by the fluoro-substrate.