FIELD: method of separating acrylonitrile or methacrylonitrile. SUBSTANCE: method includes transportation of reactor effluent produced in ammoxidation of propylene or isobutylene to column of quick cooling in which hot effluent is cooled by contact with sprayed water; passage of selected cooled effluent from column top to absorption column in which nonpurified acrylonitrile or methacryloniltile is absorbed by water; passage of aqueous solution containing nonpurified acrylonitrile or methacrylonitrile to the first decanter, where the first water layer and the first organic layer are formed and they contain acrylonitrile and methacrylonitrile; transfer of the first organic layer to the second decanter in which the second water layer and the second layer are formed and regeneration of acrylonitrile or methacrylonitrile from the second organic layer. The method is distinguished by the fact that it includes operation of the first and second decanters with their interval temperature from about of 32 F (0. C) to about 75 F (23.89 C). EFFECT: simplified process and improved quality of end product. 7 cl, 1 dwg
