METHOD FOR THE PRODUCTION OF AMINODICARBOXYLIC ACID-N,N-DIACETIC ACIDS

The present invention relates to a method for the production of aminodicarboxylic acid-N,N,diacetic acids of the general Formula I, wherein X independently of one another represents hydrogen or an alkali metal and n represents a number 1 or 2. Furthermore, the invention relates to aminodicarboxylic acid-N,N-diacetic acids of high purity. The inventive method comprises the following steps: a) reacting an aminodicarboxylic acid of the general Formula II, wherein X and n have the aforementioned meanings, with 0.8 to 1.2 mole equivalents of formaldehyde and with 0.8 to 1.2 mole equivalents of hydrocyanic acid; b) reacting the reaction products of step a) with 0.8 to 1.2 mole equivalents of hydrocyanic acid and with 0.8 to 1.2 mole equivalents of formaldehyde; c) hydrolyzing in the reaction product obtained in step b).