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:
Jun. 07, 1983
Filed:
Jun. 20, 1979
Houssam M Naim, Naperville, IL (US);
Nicholas C Huie, Naperville, IL (US);
George E Kuhlmann, Naperville, IL (US);
Standard Oil Company (Indiana), Chicago, IL (US);
Abstract
An improved two-step catalytic neat oxidation of liquid xylene is provided wherein there is no separation of oxidation products from the first oxidation step nor minimum limitation imposed on the liquid o-xylene concentration entering the second step according to the prior two-step oxidations of o-xylene. Rather the first step is conducted under conditions such that the liquid effluent from the first step contains from 6 up to 30 weight percent liquid o-xylene and from 8 up to 40 weight percent o-phthalic acid and such effluent is directly oxidized with air in the second step. By such improved two-step oxidation there is obtained a liquid product containing o-phthalic acid in yields of up to 85-87% of the theoretical yield and also containing impurities separable from o-phthalic acid after it has been converted to its anhydride in vapor form and the anhydride vapors are separated from water vapor. Such two step neat oxidation of liquid o-xylene provides a route to phthalic anhydride commercially competitive with routes starting with the vapor phase oxidation of o-xylene.