Synthesis of polyesters by reaction of carboxylic acid quaternary ammonium salts with alkyl halides or alkyl tosylates

The synthesis of polyesters by the reaction of dicarboxylic acid salts with bis halides or bis tosylates or by the self-condensation of salts of omega-bromocarboxylic acids, has been investigated under two different types of conditions. When benzyltrimethylammonium salts and halides were reacted together in acetonitrile at ca. 82 degrees C the results obtained were similar to those reported in the literature for experiments using sodium or potassium salts. Thus, the yields of polyesters were generally modest, with degrees of polymerization (DPs) being in the range from 17 to 47. Using liquid-liquid phase-transfer catalysis procedures the yields were high and the DPs were usually in the range from 22 to 161. This is the first time that the liquid-liquid phase-transfer catalysed synthesis of polyesters has produced such high DP values.