PURPOSE: To obtain the titled substance useful as a raw material for drugs, agricultural chemicals, etc. economically in high yield, by reacting acrylonitrile with ammonium chloride or an alkaline (earth) metal chloride in an aqueous solution of sulfuric acid under heating.

CONSTITUTION: Acrylonitrile (AN) is reacted with an inorganic chloride in an aqueous solution of sulfuric acid under heating to give the titled substance. Ammonium chloride, an alkali metal chloride, etc. is used as the inorganic chloride, its amount is an amount to give 1Wdouble the molar amount of AN, 60W80wt% aqueous solution of sulfuric acid in an amount to give twiceWthree times as much sulfuric acid as AN by mole is used, and the reaction is carried out at 80W125°C for 1W8hr. In a concrete reaction method, preferably given amounts of AN, the inorganic chloride, and water are added to a reactor, and conc. sulfuric acid is added dropwise to it.