Synthesis, Characterization, and Surface‐Active Properties of Carboxylbetaine and Sulfobetaine Surfactants based on Vegetable Oil

Abstract

AbstractA novel series of carboxylbetaine‐type and sulfobetaine‐type zwitterionic surfactants (castor oil amidoethyl betaine, castor oil amidoethyl sulfobetaine [CAAS], cottonseed oil amidoethyl betaine, and cottonseed oil amidoethyl sulfobetaine [COAS]) were synthesized via the reactions of nonedible vegetable oils (castor oil and cottonseed oil) with dimethylaminoethylamine, followed by the reaction with sodium chloroacetate and sodium 2‐hydroxy‐3‐chloropropane sulfonate, respectively. Their chemical structures were confirmed using the electrospray ionization mass spectrum (ESI‐MS) and infrared (IR) spectra. The surface activities of the prepared compounds were measured by surface tension. It was noticed that the sulfobetaine‐type surfactants in aqueous solution performed slightly better at reducing surface tension than the carboxylbetaine‐type surfactants. Meanwhile, the synthesized surfactants possess a broad range of isoelectric points, superior foam properties, and exhibit some antibacterial activity on Gram‐positive and Gram‐negative bacteria.