PREPARATION OF MIXTURES OF BROMINATED BENZENES PREDOMINANT IN DIBROMOBENZENES AND TRIBROMOBENZENES

摘要

This invention provides a process for preparing a mixture of brominated benzenes predominant in dibromobenzenes and tribromobenzenes. The process comprises forming and heating a reaction mixture to form an intermediate mixture, in which the catalyst is deactivated. The intermediate mixture is formed by heating the reaction mixture until a meta-dibromobenzene:para-dibromobenzene molar ratio of about 1.8: 1 or more is reached. The intermediate mixture is either i) cooled to a temperature of about 0°C or less, and the solid and liquid phases formed upon cooling are separated, or ii) monobromobenzene is removed from the intermediate mixture. The reaction mixture is formed from a Lewis acid catalyst and an aromatic substrate comprising (a) benzene and/or monobromobenzene, optionally in a mixture with partially brominated benzenes, or (b) 1,4-dibromobenzene optionally in a mixture with partially brominated benzenes; when the aromatic substrate is (a), formation of the reaction mixture includes feeding bromine into the mixture.