Patent ID: 8710155

Claim:
A process comprising a) contacting an unsaturated compound containing aliphatic carbon-carbon double bonds with a quaternary ammonium tribromide or a quaternary phosphonium tribromide in the presence of at least one solvent for the unsaturated compound under conditions such that the unsaturated compound becomes brominated and, as a by-product, (1) a mixture of a quaternary ammonium monobromide salt and a quaternary ammonium monochloride salt or (2) a mixture of a quaternary phosphonium monobromide salt and a quaternary phosphonium monochloride salt is formed, b) separating the quaternary ammonium monochloride salt or quaternary phosphonium monochloride salt from the brominated unsaturated compound, then c) contacting a solution of said separated quaternary ammonium or quaternary phosphonium monochloride salt with a source of bromide ions under conditions that at least a portion of the quaternary ammonium or quaternary phosphonium monochloride salt reacts with said source of bromide ions to regenerate a quaternary ammonium monobromide salt or quaternary phosphonium monobromide salt and a chloride by-product; d) contacting the regenerated quaternary ammonium monobromide salt or regenerated quaternary phosphonium monobromide salt with bromine to form the corresponding quaternary ammonium tribromide or quaternary phosphonium tribromide; and then e) before, during or after step d), separating the chloride by-product from the regenerated quaternary ammonium or quaternary phosphonium monobromide salt or quaternary ammonium or quaternary phosphonium tribromide and then f) recycling quaternary ammonium tribromide or quaternary phosphonium tribromide obtained in step d) back into step a).