Process for the preparation of bis(amidocarboxylic acids)

A process for the preparation of a bis(amidocarboxylic acid) having the formula:

• ##STR8## wherein R and R.sup.1 are each independently a C.sub.1 -C.sub.12 radical selected from the group consisting of alkylene, alkenylene, cycloalkylene, cycloalkenylene, arylene and phenylene radicals;
• and
• R.sup.2 is hydrogen or a C.sub.1 -C.sub.12 radical selected from the group consisting of alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl and phenyl radicals;
• the process comprising the steps of:
• (i) charging a reactor with a reaction medium that includes a C.sub.1 -C.sub.8 mono- or polyhydric alcohol as solvent, an ester and an aminocarboxylate compound, the ester having the formula:
• ##STR9## wherein R.sup.3 is a C.sub.1 -C.sub.6 radical selected from the group consisting of alkyl, haloalkyl, hydroxyalkyl and phenyl radicals, the aminocarboxylate compound being a salt formed from and selected from the group consisting of lactams having the formula:
• ##STR10## and aminocarboxylic acids having the formula:
• ##STR11## the ester and aminocarboxylate compound being present in a respective weight ratio of from about 1:1 to about 1:4;
• (ii) reacting the ester with the aminocarboxylate compound;
• and
• (iii) recovering the bis(amidocarboxylic acid) from the reaction medium.