Process for preparing n-acyl amino acid salts

Abstract

N-Acyl amino acid salt compositions and an improved process for making them from fatty alkyl esters are disclosed. The process comprises reacting a fatty alkyl ester with an amino acid salt in the presence of an alkoxide catalyst at a pressure of at least 5 psig. At least 10 mole percent of catalyst is used based on the amount of fatty alkyl ester used as a reactant. Pressure and a minimum level of alkoxide catalyst are needed to give high fatty alkyl ester conversions and good yields of the desired N-acyl amino acid salt. The resulting N-acyl amino acid salt compositions have low color, an acceptable level of fatty acid soaps, and a small proportion of di-acylated by-products. Single-phase mixtures produced by combining various amino acid salts with glycinates, or by using an excess of either the fatty alkyl ester or amino acid salt, promote high conversions when the mixtures are reacted to give the desired N-acyl amino acid salt.