Synthesis and Properties of Tetradecyltrimethylammonium Carboxylates

Abstract

A series of tetradecyltrimethylammonium carboxylates based on the general formula-CH 3 (CH 2 ) 12 CH 2 N þ (CH 3 ) 3 Á -OOCCH 2 (CH 2 ) n CH 2 CH 3 (n ¼ 4, 6, 8) were synthesized. The tetradecyldimethylamines were quaternized with dimethyl carbonate, followed by reaction with different carboxylic acids to prepare the tetradecyltrimethylammonium carboxylates, and their structures were characterized by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. The critical micelle concentration and the minimum surface tension of these surfactants were also studied. The results indicated that the prepared surfactants could reduce the surface tension of water to 21-26 mN/m at concentration levels of 10 À4 mol/L. Furthermore, their wetting ability and emulsifying ability were also investigated.