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:
Jun. 25, 1991
Filed:
Feb. 22, 1990
Mark W Meszaros, Batavia, IL (US);
Amoco Corporation, Chicago, IL (US);
Abstract
A regioselective process is provided for preparing 4-bromo-o-xylene in an isomer mixture of 4-bromo-o-xylene and 3-bromo-o-xylene by combining bromine with o-xylene in liquid sulfur dioxide medium. A bromine to o-xylene mole ratio of about 0.4:1 to about 1:1 is utilized at a temperature in the range of about -20.degree. C. to about 40.degree. C. While preferred temperatures are in the about -15.degree. C. to about -9.degree. C. range, temperatures above about -9.degree. C. can be used by maintaining the reactant solution under pressure. A product isomer mixture can be isolated by vacuum distillation. A 92:8 weight ratio mixture of 4-bromo-o-xylene and 3-bromo-o-xylene is thus obtainable.