Catalyst recovery for halogen exchange reactions

摘要

It has been found possible to separate catalytically-active aminophosphonium catalysts from mixtures composed predominately of aminophosphonium catalyst residue(s) and heavy ends from a halogen exchange reaction conducted in an aprotic solvent/diluent by extracting such mixtures with a neutral or acidic aqueous extraction solvent medium. Various ways of isolating from the halogen exchange reaction product mixture a mixture composed predominately of aminophosphonium catalyst residue(s) and heavy ends are described. Halogen exchange processes in which the catalytically-active aminophosphonium catalysts are separated for reuse are also described. Since aminophosphonium catalysts are expensive, the present process technology fulfills a need which has existed for an effective way of recovering such catalysts in catalytically active form enabling reuse of such materials, especially as halogen exchange catalysts.