Liquid phthalic anhydride recovery process using a rectification tower
US5731443A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 2, 1995 |
| Grant date | Mar 24, 1998 |
| Priority date | — |
| Expiry date | May 2, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/573
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for recovering phthalic anhydride as a liquid from a vapor phase oxidation product which comprises mixing the vapor phase oxidation product having a temperature in the range of about 130.degree. C. or greater with a first stream comprising maleic anhydride and/or at least one compound selected from the group consisting of: citraconic anhydride, benzoic acid and phthalic anhydride in a rectification tower such that a substantial portion of the phthalic anhydride contained within the vapor phase oxidation product transfers from the vapor phase to a liquid phase and the by-products contained in the first stream which are more volatile than phthalic anhydride transfer from the liquid phase to the vapor phase and wherein a vapor-to-liquid weight ratio in the range between about 5 to 20 is exhibited within the rectification tower, thereby forming a liquid phase phthalic anhydride product having a phthalic anhydride concentration in the range between about 50-100 wt. %, preferably 90-100 wt. %, without the formation of an intermediate solid phase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.