Patent ID: 6838557

Claim:
A process for making a chelating agent comprising: providing a tertiary amine where said tertiary amine is cyclic having the general formula: (R 1 ) 1 (—(CH 2 ) m —NR 2 —) x-2 —(CH 2 ) n —NR 3 —) 1 where n is 2 or 3; x is 3, 4 or 6; R 1 is((CH 2 ) n —NR 2 —) 1 when said tertiary amine is cyclic; R 2 is a substituent that includes a first ester group having the general formula: R 4 —O—(C═O)—(Y) m — where m is between 1 and 20, Y is a branched or linear organic substituent and wherein R 4 includes an organic substituent selected from the group consisting of alkyl groups having 20 carbon atoms or less, cycloalkyl groups having 20 carbon atoms or less and aromatic groups having 20 carbon atoms are less; and R 3 is a substituent that includes a carboxylic acid group and at least one carbon atom in R3 is attached to any one Nitrogen atom in the tertiary amine and said at least one carbon atom is between said one Nitrogen atom and said carboxylic acid group, and said R 2 is attached to remaining Nitrogen atoms of said tertiary amine; and combining said tertiary amine with a coupling agent and an active compound selected from the group consisting of imide-containing compounds, aryl-containing compounds with electron withdrawing groups and triazol-containing compounds to convert said R 3 to a second ester group and thereby form an active ester.