Glycolide production process, and glycolic acid oligomer for glycolide production

The invention relates to a glycolide production process wherein a depolymerization reaction system comprising a glycolic acid oligomer or a glycolic acid oligomer and a polar organic solvent is heated to depolymerize the glycolic acid oligomer into glycolide, the resulting glycolide or the glycolide and polar organic solvent are distilled out of the depolymerization reaction system, and the glycolide is recovered from distillates obtained by distillation. The glycolic acid oligomer or the glycolic acid oligomer and polar organic solvent are continuously or intermittently charged into the depolymerization reaction system, thereby carrying out depolymerization reactions continuously or repeatedly. During the depolymerization reactions, a compound having an alcoholic hydroxyl group is permitted to exist at a specific quantitative ratio in the depolymerization reaction system. The invention is also concerned with a glycolic acid oligomer for the production of glycolide, which is obtained by condensation of glycolic acid in the presence of the compound having an alcoholic hydroxyl group.