Micellar-improved synthesis of bis-quaternary ammonium salts by the epichlorohydrin route

Abstract

A convenient procedure for the synthesis of bis-quaternary ammonium salts from long-chain alkyldimethylamines and epichlorohydrin is studied. An improved preparation of bis-quaternary ammonium salts from N,N-dimethyloctylamine, N,N-dimethyldodecylamine or N,N-dimethyloleylamine, their amine hydrochlorides, and epichlorohydrin can be achieved by carrying out the reaction in an aqueous micellar medium. The amine hydrochlorides are used as functional surfactants to produce the self-micellization and solubilization of reactants. The formation of micelles is a necessary condition for a successful quaternization. Comparison of the quaternization performance in ethanol, ethanol/water mixtures, and aqueous micellar medium leads to the conclusion that this micellar-improved synthesis enables easier and cheaper access to bis-quaternary ammonium salts by avoiding the formation of the mono-quaternary ammonium salts as intermediates, and by using water as solvent under mild reaction conditions. Mechanistic aspects of the quaternization reaction in micellized medium are also suggested.