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:
Aug. 16, 1983
Filed:
Sep. 18, 1981
Nicholas P Greco, Pittsburgh, PA (US);
Koppers Company, Inc., Pittsburgh, PA (US);
Abstract
A process is disclosed for making 1,3-cyclic diones by vapor-phase cyclization of delta-keto carboxylic acid esters over a carbon catalyst bed. The delta-keto ester is conveyed through the catalyst bed by a carrier gas characterized by being liquid at 25.degree. C. and having a sufficiently high boiling point that the carrier gas is easily condensable under ambient conditions. The delta-keto ester is highly soluble in the liquid carrier, while the cyclic dione product of the ester has very low solubility in the liquid carrier. Use of the described carrier in vapor-phase cyclization of delta-keto esters allows efficient separation of cyclic dione product and unreacted starting material from the carrier after the cyclization reaction.