US Patent 7550551 Brominated flame retardant

A process for preparing a polybromoaryl ether comprising adding to a solvent for the polybromoaryl ether a mixture of (1) at least one compound of the structure HO—Ar—X1, X2, X3, X4, X5, wherein Ar is an aryl group and X1, X2, X3, X4, and X5 are independently selected from hydrogen and bromine, provided that at least one of X1, X2, X3, X4, and X5 is bromine, (2) at least one alkali or alkaline metal hydroxide, and (3) at least one polymerization initiator, wherein the solvent for the polybromoaryl ether is a non-solvent for alkali metal bromides.