PROCESS TO PREPARE AMINO ACID-N, N-DIACETIC ACID COMPOUNDS

摘要

The invention relates to a process for the production of an amino acid having at least one secondary or tertiary amino group and three or more carboxyl groups or its salt with less than an equivalent of alkaline metal based on the number of carboxyl groups, said process comprising reducing alkali metal ions from an aqueous solution of an alkali metal salt of an amino acid having at least one secondary or tertiary amino group and three or more carboxyl groups and acidifying the amino carboxylate starting material by first performing a chemical acidification step using an organic or inorganic acid to get a compound in which at least one of the groups is protonated, and in a subsequent step further acidifying the amino carboxylate starting material and reducing alkali metal ions from an aqueous solution of the partially acidified alkali metal salt of the amino acid having at least one secondary or tertiary amino group and three or more carboxyl groups by electrodialysis, wherein the electrodialysis is performed using a hydrogen ion permselective membrane on the anode side and a cation-permeable membrane on the cathode side.