Process for the synthesis of lactide or glycolide from lactic acid or glycolide acid oligomers
US5374743A · kind A · utility
3Cited by
3References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1993 |
| Grant date | Dec 20, 1994 |
| Priority date | — |
| Expiry date | Sep 30, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D319/12
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for preparing lactide or glycolide from a lactic acid oligomer or glycolic acid oligomer is disclosed where the molecular weight of the synthesis reactor residue is controlled to no more than 1.2 times that in the feed. The process is carried out at 130.degree. to 280.degree. C. and preferably 180.degree. to 210.degree. C. using from 1 to 6 weight percent catalyst in the oligomer feed to the synthesis reactor. The catalysts are tin or tin compounds, yttrium or rare earth metal compounds, or antimony compounds which are known as alphahydroxycarboxylic acid cyclic dimerization or polymerization catalysts.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.