Recovery of lactic acid values from a meso-lactide stream
US8552209B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 12, 2010 |
| Grant date | Oct 8, 2013 |
| Priority date | — |
| Expiry date | Mar 12, 2030 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D319/12
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Lactic acid equivalents are recovered from a starting lactide stream by catalytically racemizing a portion of the lactide in the stream at a temperature of 180° C. or below. This increases the proportion of two species of lactide (i.e., at least two of S,S-, R,R- or meso-lactide) at the expense of the third species. The racemized mixture so obtained can be separated to recover some or all of one or more of the lactide species from the remaining lactide species, by a process such as melt crystallization or distillation. Impurities in the starting lactide stream usually are retained mostly in the remaining meso-lactide, so a highly purified S,S- and/or R,R-lactide stream can be produced in this manner. Such a purified S,S- and R,R-lactide stream is suitable for polymerization to form a polylactide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.