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:
Sep. 26, 1995
Filed:
Jun. 02, 1994
Hoffmann-La Roche Inc., Nutley, NJ (US);
Abstract
A process is described for the manufacture of .beta.-ionone by the sulphuric acid-catalyzed cyclization of pseudoionone in a two-phase solvent system comprising concentrated sulphuric acid and a second solvent essentially immiscible with water, which process comprises using carbon dioxide liquefied under pressure as the second solvent. This process is carried out, inter alia, under a pressure of about 50 bar to about 150 bar and at temperatures from about -15.degree. C. to about +15.degree. C. prior to the subsequent stopping (quenching) of the cyclization reaction. The process in accordance with the invention is preferably carried out continuously and is an important intermediate stage in the synthesis of vitamin A.