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:
Jul. 04, 2000
Filed:
Apr. 16, 1999
Shiao-Jung Chu, Hsin Chu, TW;
Chian-Liang Hwang, Kao Hsiung, TW;
Chinese Petroleum Corp., Taipei, TW;
Abstract
The present invention relates to a process for preparing pyromellitic dianhydride via an oxidation in gas phase under normal pressure. The process is characterized in that a catalyst system is used, which catalyst system comprises a catalyst which is a mixture of vanadium and tungsten oxides; a catalyst support comprising rutile and at least one material selected from the group consisting of tungsten carbide, silicon carbide and a mixture thereof; and a cocatalyst comprising oxides of manganese, antimony, bismuth, phosphorus, copper, aluminum, titanium or a mixture thereof, an oxide of an element of the VIIIB group of the periodic table, and an oxide of an alkali metal and/or alkaline earth metal. In this process, pyromellitic dianhydride is produced from a feedstream containing 1,2,4,5-tetraalkylbenzene in a gas flow rate of 4,000.about.12,000 hr.sup.-1 via a selective oxidation at 300.about.450.degree. C. in the presence of air which acts as an oxidant.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile