PROCESS FOR PRODUCING ALPHA.BETA-UNSATURATED NITRILE

A process for producing an alpha , beta -unsaturated nitrile from propylene, isobutylene or tert-butyl alcohol in an industrial fluidized reactor with the step of feeding methanol and an oxygen-containing gas in the course of the whole contact time of the reactor and reacting unreacted ammonia with the methanol and the oxygen-containing gas, which can reduce the amount of unreacted ammonia without lowering the yield of the nitrile; and an industrial process of conducting the above production in an industrial fluidized reactor having an inner diameter of 3 m or above and filled with a molybdenum-bismuth catalyst supported on silica, which can prevent the feed opening of a dispersing nozzle for the methanol from clogging with molybdenum oxides to attain constant reduction in the amount of unreacted ammonia. The former is a process of catalytically reacting propylene, isobutylene or tert-butyl alcohol with ammonia and an oxygen-containing gas at high temperature in a gas phase by the use of a fluidized bed catalyst to form an alpha , beta -unsaturated nitrile having the same number of carbon atoms as that of the starting propylene, isobutylene or tert-butyl alcohol, wherein methanol and an oxygen-containing gas are fed into the fluidized reactor at the positions corresponding to one-half to nine-tenths of the whole contact time from the point of feeding the starting materials through gas dispersing nozzles; and the latter is a process of producing an alpha , beta -unsaturated nitrile as described above, wherein the methanol is fed together with steam through the same gas dispersing nozzle to thereby inhibit the catalyst from adhering to the dispersing nozzle and remove the catalyst adherent thereto.