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:
Feb. 26, 1991
Filed:
Dec. 20, 1989
Applicant:
Inventors:
Andreas B Ernst, Glen Ellyn, IL (US);
Gunter Caspari, Wheaton, IL (US);
Assignee:
Amoco Corporation, Chicago, IL (US);
Primary Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
568 33 ;
Abstract
A process is described to make a dihydroxydiphenol sulfone product with a 4,4'-dihydroxydiphenol sulfone purity in excess of 90 wt. % by reaction of phenol and concentrated sulfuric acid in a solvent mixture containing a lower-boiling and a higher-boiling hydrocarbon, removal by azeotropic distillation of water, hydrocarbon, and phenol, phase separation of the distillate, and return of at least the phenol to the reaction at a rate which maintains a phenol to sulfuric acid mol ratio in the reaction of at least 2 to 1.