Method for purifying hydroxycarboxylic acid, method for producing cyclic ester, and method for producing polyhydroxycarboxylic acid
US8039548B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 10, 2007 |
| Grant date | Oct 18, 2011 |
| Priority date | — |
| Expiry date | May 5, 2028 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G63/08
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for purification of a hydroxycarboxylic acid by distillation, comprising: distilling a hydroxycarboxylic acid solution containing a high-boiling point hydroxy compound comprising at least one species selected from the group consisting of alcohols and phenols having a higher boiling point than the hydroxycarboxylic acid. As a result, a hydroxycarboxylic acid suitable as a starting material for production of a polyhydroxycarboxylic acid can be obtained. The purified hydroxycarboxylic acid is further polycondensed to provide a hydroxycarboxylic acid oligomer, which is de-polymerized to provide a cyclic ester comprising a dimer of the hydroxycarboxylic acid, and the cyclic ester is converted into a polyhydroxycarboxylic acid by ring-opening polymerization thereof.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.