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. 17, 1987
Filed:
Dec. 20, 1985
Avinash Kachhy, Edison, NJ (US);
Stauffer Chemical Company, Westport, CT (US);
Abstract
A process for purifying crude substituted phthalic anhydrides, e.g. 4-methylphthalic anhydride, derived from the dehydrogenation in the presence of bromine of a Diels-Alder addition product of a conjugated diene, e.g. isoprene, and maleic anhydride. In this process, a mixture of the crude, liquid substituted phthalic anhydride, e.g. 4-methylphthalic anhydride, and an alkali is heated to a temperature effective to reduce the impurities present in the crude substituted phthalic anhydride. Suitable alkalis can include sodium hydroxide and sodium carbonate. Mild alkalis are heated to a higher temperature, e.g. 130.degree. C. for sodium carbonate, whereas stronger alkalis are heated to a lower temperature, e.g. 90.degree. C. for sodium hydroxide.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile