Glycolide
Glycolide is a dimer of glycolic acid. Its structure is six-membered ring containing two lactones, an oxidized variant of p-dioxane. The compound can be synthesized from glycolic acid, via a high-temperature oligomerization to form polyglycolide followed by a depolymerization process. A more direct method is by self-condensation of the sodium salt of chloroacetic acid. It is useful as a starting material for the production of polyglycolide.