Patent ID: 8399686

Claim:
A process for preparing a cyclic ester having the formula: wherein each x is the same and is an integer ranging from 0 to 12; wherein each R 1a and each R 1b , when present, is independently hydrogen, hydroxy, amino, thio, halogen, substituted or unsubstituted C 1 -C 6 alkyl, substituted or unsubstituted C 1 -C 6 alkoxy, substituted or unsubstituted C 1 -C 6 alkylthio, substituted or unsubstituted C 1 -C 6 alkylamino, or substituted or unsubstituted C 1 -C 6 hydroxyalkyl; provided that each R 1a is the same and each R 1b is the same; wherein R 2 is hydrogen, hydroxy, amino, thio, halogen, substituted or unsubstituted C 1 -C 6 alkyl, substituted or unsubstituted C 1 -C 6 alkoxy, substituted or unsubstituted C 1 -C 6 alkylthio, substituted or unsubstituted C 1 -C 6 alkylamino, or substituted or unsubstituted C 1 -C 6 hydroxyalkyl; and wherein is an optional bond; the process comprising heating a liquid reaction medium comprising an oligomeric α-hydroxyacid having the formula: or a salt thereof, wherein n is an integer from 2 to 30, and wherein x, R 1a , R 1b , R 2 and are the same as defined above, at a temperature of from about 150° C. to about 300° C. to form the cyclic ester, while removing from the liquid reaction medium a composition comprising the cyclic ester.