PURPOSE: To obtain the title compound in an improved way by removing alkali metal salt from a solution containing a betaine compound, low-molecular weight organic cationic compound and alkali metal slat, by electrodialysis.
CONSTITUTION: The objective betaine compound can be obtained by removing alkali metal salt from a solution containing a betaine compound, low-molecular weight organic cationic compound and alkali metal salt, by electrodialysis using (1) a cation exchange membrane prepared by oxidative polymerization of an relevant aromatic compound the surface or surface layer of a sulfone-type cation exchange membrane 0.05-0.3 (g water/g wet resin) in water content or (2) another cation exchange membrane prepared by treatment with an aldehyde of the above cation exchange membrane 1. With the present production method, the dimensional growth and efficiency decline for the cation exchange membrane will be avoided, enabling easy production of the objective betaine excellent in stability.
KUBO MAKOTO
IMOTO HIROYUKI
MITOBE HIROYUKI
