Abstract: The invention comprises a method of inhibiting the formation of foulants and residues, gums and precipitates, polymeric tars and other highly oxidized carbonaceous tars which can be formed in the process of manufacture and recovery of acrylonitrile. The method comprises adding to the liquid or gaseous phases passing through, or stored in acrylonitrile process equipment, an effective antifouling amount of a dispersant which is stable in the environment within an acrylonitrile process and is neutral to the equipment used for the manufacture of acrylonitrile.