Abstract: Acrylonitrile is a monomer that is widely used in the synthesis of a vast variety of polymers. Undesirable quantities of unpolymerized residual acrylonitrile are often present in these acrylonitrile polymers. This residual or free acrylonitrile dissolved in an acrylonitrile polymer and/or its emulsifier system and the water phase used in its polymerization can be reduced significantly in concentration by treatment with oximes. Oximes react with acrylonitrile by an oxygen-cyanoethylation reaction which results in the formation of a cyanoethyl oximino ether linkage.