Abstract: Crude acetonitrile containing impurities such as hydrogen cyanide, allyl alcohol, oxazole and water is purified by a process including the steps of removing water lower part acetonitrile is treated with an alkali in an amount sufficient to extract water present in the crude acetonitrile, to be thereby divided into an organic liquid phase and an aqueous liquid phase, and the aqueous liquid phase is removed.

Abstract: Crude acetonitrile containing impurities such as hydrogen cyanide, allyl alcohol, oxazole and water is purified by at least one of the following processes (i) through (iv). (i) Process of removing hydrogen cyanide wherein crude acetonitrile is treated with an alkali in an amount sufficient to convert a substantial part of the free hydrogen cyanide present in the crude acetonitrile to an alkali metal cyanide but insufficient to convert a substantial part of the combined hydrogen cyanide present in the crude acetonitrile to an alkali metal cyanide; and then, the so obtained reaction mixture is subjected to distillation under reduced pressure.