The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 24, 1998
Filed:
May. 02, 1995
Herbert Peter Dengler, Baton Rouge, LA (US);
James Joseph Baiel, Morris Plains, NJ (US);
Exxon Chemical Patents Inc., Houston, TX (US);
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.