Process for making mixtures of chelating agents

A process for making a chelating agent comprising:

• (A) a compound according to formula (I):
• R1—CH(COOX1)—N(CH2COOX1)2 (I)
• (B) at least one compound having a formula selected from the group consisting of formulae (III a) and (III b):
• R1—CH(COOX1)—N(CH2COOX1)(CH2CONH2) (III a)
• R1—CH(COOX1)—N(CH2CONH2)2 (III b);
• and
• in total 1 ppm to 1.5% by weight of an inorganic non-basic salt based on a total amount of components (A) and (B),
• wherein:
• R1 is selected from the group consisting of C1-C4 linear alkyl, C1-C4 branched alkyl, phenyl, benzyl, CH2OH, and CH2CH2COOX1,
• X1 is (NaxH1−x),
• x is in a range of from 0.6 to 1, and
• wherein component (A) and component (B) are present in a molar ratio in a range of from 2:1 to 0.1:1,
• the process comprising:
• (a) contacting a solid, a slurry or a solution of a compound according to formula (II)
• R1—CH(COOX2)—N(CH2CN)2 (II)
• wherein:
• X2 is (NayH1−y),
• y is in the range of from zero to 1,
• with an aqueous solution of sodium metal hydroxide, wherein a molar ratio of sodium metal ions to nitrile groups is in a range of from 0.6:1 to 0.95:1, and
• (b) reacting the compound according to formula (II) with the sodium metal hydroxide.