Solvent assisted process for recovery of phthalic anhydride in the liquid phase by distillation
US5718808A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 29, 1996 |
| Grant date | Feb 17, 1998 |
| Priority date | — |
| Expiry date | Nov 29, 2016 |
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 of about 130.degree. C. or greater with a first stream comprising a solvent having a boiling point in the range between about 150.degree. to 350.degree. C. and a freezing point of less than 40.degree. C., and, optionally, at least one by-product selected from the group consisting of: maleic anhydride, citraconic anhydride, benzoic acid and phthalic anhydride, in a contacting means 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 a substantial portion of 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 2 to 20 is exhibited within the contacting means, 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.