Abstract: The hydrolytic stability,foaming power and foam stability,lime soap dispersing power and Krafft point of fatty acid methyl ester sulfonate (MES) were measured by potentiometric titration,Ross-Miles foam instrument,improved acidometric titration and turbidimetric test,respectively.The stability and detergency of the liquid detergent containing MES were also tested.The results show that when the storage temperature is 45 ℃,MES is stable at pH 4.5-9.0,however,when pH is 10.0,the mass fraction of disodium salt ofα-sulfonated fatty acid (DS) increases,indicative of obvious hydrolysis;MES shows excellent lime soap dispersing power with a value of 2.5 g calcium soap per gram of MES (In contrast,the value for LAS is 0.34 g calcium soap per gram of LAS);The Krafft point of MES is approximately 20.9 ℃;The liquid detergent products containing MES have excellent stability,and the detergency performance can meet the requirements of the national standard.

Key words: fatty acid methyl ester sulfonate, hydrolytic stability, lime soap dispersing power, liquid detergent