Addition of hydrogen to carbon monoxide feed gas in producing acetic acid by carbonylation of methanol
US4994608A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 5, 1987 |
| Grant date | Feb 19, 1991 |
| Priority date | — |
| Expiry date | Aug 5, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/12
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The carbonylation of an alcohol to produce a carboxylic acid, especially methanol to produce acetic acid, in a low water reaction medium containing a rhodium catalyst stabilized with an iodide salt, especially lithium iodide, along with alkyl iodide such as methyl iodide and alkyl acetate such as methyl acetate in specified proportions is improved by the addition of hydrogen in the feed gas to the low water reaction medium to obtain a reactor hydrogen partial pressure of at least about 4 psi. The presence of hydrogen in the reaction medium increases significantly the carbonylation reaction rate and reduces formation of byproduct carbon dioxide. The present reaction system not only provides an acid product of unusually low water content at unexpectedly favorable reaction rates but also, whether the water content is low or, as in the case of prior-art acetic acid technology, relatively high, is characterized by unexpectedly high catalyst stability; i.e., it is resistant to catalyst precipitation out of the reaction medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.