Method of producing aromatic carboxylic acids by oxidizing alkyl aromatic hydrocarbons or partially oxidized intermediates thereof
US6194607A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 3, 1999 |
| Grant date | Feb 27, 2001 |
| Priority date | — |
| Expiry date | Dec 3, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P20/52
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
An improved production method of aromatic carboxylic acid products of significantly improved yield and quality by oxidizing alkyl aromatic substrates or their partially oxidized intermediates in a conventional MC-type catalyst system modified to contain additional components such as alkali metal or alkaline earth metal in an acetic acid medium in a feed gas containing oxygen and optionally carbon dioxide. Since carbon dioxide functioned as a co-oxidant along with oxygen in the oxidation reaction, the oxidation reaction proceeds more selectively to produce the carboxylic acid product much faster under milder reaction conditions over the conventional MC-type oxidation. In particular, the oxidation of para-xylene carried out by the novel present method enabled production of terephthalic acid of higher yield and enhanced quality, which were improved far more than the extent that generally could be expected by current PTA producers. The present invention also provides an effective purification process to produce highly pure terephthalic acid or isophthalic acid by the oxidation of impurities such as 4-carboxybenzaldehyde and para-toluic acid or 3-carboxybenzaldehyde and meta-toluic acid…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.