The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 26, 2007
Filed:
Apr. 10, 2002
Kazuyuki Yamane, Fukushima, JP;
Yukichika Kawakami, Fukushima, JP;
Kazuyuki Yamane, Fukushima, JP;
Yukichika Kawakami, Fukushima, JP;
Kureha Corporation, Tokyo, JP;
Abstract
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.