Citric acid and citramalic acid preparation
US4022823A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 1976 |
| Grant date | May 10, 1977 |
| Priority date | — |
| Expiry date | Apr 26, 1996 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/27
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for the preparation of citric acid which comprises contacting an unsaturated compound selected from 3-methylene-1,5-pentanediol and its esters with a nitric acid solution in an amount of 2 to 50 mols of nitric acid feed per mol of unsaturated compound feed, and at least 0.005 mol percent nitrogen dioxide based on nitric acid, at a temperature between -10.degree. and 120.degree. C., to thereby oxidize said unsaturated compound to citric acid. Preferably the contacting of the unsaturated compound so as to synthesize citric acid is carried out in the absence of any substantial amount of vanadium as the presence of vanadium catalysts has been found to effectively prevent the recovery of good yields of citric acid from the process. The citric acid synthesis preferably is carried out by an overall process wherein isobutene is reacted with two mols of formaldehyde to produce 3-methylene-1,5-pentanediol, which is then converted to citric acid by reaction with nitrogen dioxide/nitric acid. Citramalic production from 3-methyl-3-buten-1-ol is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.