Synthesis of Rice Bran Fatty Acids (RBFAs) Based Cationic Surfactants and Evaluation of Their Performance Properties in Combination with Nonionic Surfactant

Cationic surfactants are mainly used for fabric softening in laundry applications. Esterquats are one class of cationic surfactants and are superseding other existing cationic surfactants on account of their excellent biodegradability. However, indigenous and cost-effective production of esterquats poses new challenges for the researchers. The availability of rice bran fatty acids and its price structure in Indian scenario makes this fatty feed-stock quite lucrative for cost-effective synthesis of cationic surfactants. In the present study, esterquats based on rice bran fatty acids (RBFAs) were synthesized by using different alkanol-amines i.e. diethanolamine (DEA) and triethanolamine (TEA) and dimethyl sulphate (DMS) for obtaining cationic surfactants which was used as active softener ingredient. For this purpose, esterquats have been synthesized by esterification of RBFAs and alkanolamines to recover diesters followed by the subsequent quaternization of diesters by DMS. It was found that the optimum reaction conditions for esterification of RBFAs and DEA was 140 degrees C and 3 h of duration. However, for RBFAs and TEA, it was found to be 140 degrees C and 4 h of duration. The chemical structures of diesters and esterquats were confirmed by FT-IR and NMR spectra. Studies of surface active and performance properties of these surfactants showed that esterquats based on TEA had better surface active and performance properties as compared to DEA based esterquats. The synthesized cationic surfactants when mixed with nonionic surfactant showed better performance properties as compared to the nonionic surfactant alone.