Method for the preparation of lactic acid and calcium sulphate dihydrate
US6632966B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 30, 2001 |
| Grant date | Oct 14, 2003 |
| Priority date | — |
| Expiry date | Aug 30, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/44
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The invention relates to a method for the preparation of lactic acid and calcium sulphate, in which (a) an aqueous solution that contains lactate is reacted with sulphuric acid at a temperature that is essentially higher than the transition temperature of calcium sulphate dihydrate (CaSO4.2H2O), with the formation of a mixture that contains calcium sulphate hemihydrate and lactic acid, (b) the mixture from step (a) is subjected to at least one recrystallization step at a temperature that is essentially lower than the transition temperature of calcium sulphate dihydrate, with the formation of a precipitate of calcium sulphate dihydrate and an aqueous solution of lactic acid, and (c) the precipitate of calcium sulphate dihydrate is separated off from the aqueous solution of lactic acid.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.