Process for preparing 1,3,6,8-tetrabromopyrene

US4684753A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Siegfried Schiessler · Frankfurt am Main, DE
• Ernst Spietschka · Idstein, DE

Key dates

• Filing date: Sep 12, 1986
• Grant date: Aug 4, 1987
• Expiry date: Sep 12, 2006

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C17/12
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

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.