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. 04, 1987
Filed:
Sep. 12, 1986
Siegfried Schiessler, Bad Soden am Taunus, DE;
Ernst Spietschka, Idstein, DE;
Hoechst Aktiengesellschaft, , DE;
Abstract
Process for preparing 1,3,6,8-tetrabromopyrene by brominating pyrene in aqueous suspension with simultaneous reoxidation of the resulting hydrogen bromide to bromine by means of an oxidizing agent, which comprises reacting pyrene in a highly concentrated aqueous suspension having a pyrene-water weight ratio of 1:1.2 to 2 with bromine at temperatures of 40.degree. to 65.degree. C. with simultaneous reoxidation of the resulting hydrogen bromide to bromine using an oxidizing agent, completing the bromination by heating the reaction mixture to temperatures of 70.degree. to 130.degree. C., reducing excess bromine with a reducing agent to hydrogen bromide and subjecting the 1,3,6,8-tetrabromopyrene formed, preferably without intermediate isolation, to an alkaline aftertreatment at temperatures of 40.degree. to 100.degree. C. within the pH range 8.5 to 12.