process for preparing tri (alkali metal) salt of n-n-diacetic methylglycine acid

PROCESS FOR PREPARING TRI SALT (ALKALINE METAL) OF N-DIACHETIC METHYLGLYCIN ACID. The invention relates to a process for producing tri-alkali metal salt of the lightly colored, low by-product methylglycine-N, N-dietanoic acid by alkaline hydrolysis of the diacetonitrile methylglycine, said process comprising the steps which are carried out in order (a) to (f): (a) mixing the methylglycine diacetonitrile with an aqueous alkaline bleach at a temperature = 30 ° C; (b) the aqueous alkaline diacetonitrile methylglycine suspension is then reacted at a temperature ranging from 10 to 30 ° C over a period of 0.1 to 10 hours to form a solution; (c) the solution obtained in step (b) is then reacted at a temperature ranging from 30 to 40 ° C for a period of 0.1 to 10 hours; (d) optionally, the solution obtained in step (c) is reacted at a temperature ranging from 50 to 800 ° C for a period of 0.5 to 2 hours; (e) optionally, the solution obtained in step (c) or (d) is reacted at a temperature ranging from 110 to 200 ° C for a period of 5 to 60 min; (f) hydrolysis and isolation of ammonia from the solution obtained in step (c), (d) or (e) by depletion at a temperature between 90 and 105 ° C.