5-methyl-1,3-dioxolane-2,4-dione

Lactic acid O-carboxyanhydride (lac-OCA) is an organic compound. It is used as a monomer equivalent to lactic acid or lactide in the preparation of poly(lactic acid). When this monomer undergoes ring-opening polymerization, one equivalent of carbon dioxide gas is released for every lactic acid unit incorporated into the polymer. This compound is prepared by treatment of lactic acid or its salts with phosgene or one of its equivalents, e.g. diphosgene.