Method for recovering phthalic anhydride/maleic anhydride mixtures by distillation
US5869700A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 21, 1997 |
| Grant date | Feb 9, 1999 |
| Priority date | — |
| Expiry date | Feb 21, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/573
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for recovering phthalic anhydride and maleic anhydride from a maleic anhydride-rich vapor phase oxidation product comprising the step of: contacting the vapor phase oxidation product with: (i) at least one by-product stream having a freezing point which is lower than the freezing point of pure phthalic anhydride; and/or (ii) 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.; 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. % and a first vapor stream.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.