Abstract: Adiponitrile is made by reacting 3-pentenenitrile with hydrogen cyanide. The 3-pentenenitrile is made by reacting 1,3-butadiene with hydrogen cyanide and by isomerizing 2-methyl-3-butenenitrile. The reaction of 1,3-butadiene with hydrogen cyanide to produce 3-pentenenitrile also produces small amounts of dinitrile compounds, including adiponitrile (ADN) and methylglutaronitrile (MGN). Methylglutaronitrile is removed to provide an adiponitrile-enriched stream, which is used in a catalyst purification step.

Abstract: A hydrocyanation reaction is used to react 1,3-butadiene with hydrogen cyanide in the presence of a catalyst to produce pentenenitriles, as well as reaction byproducts, such as methylglutaronitrile (MGN). The effluent from the hydrocyanation reaction is distilled in a particular manner to produce a pentenenitrile-enriched stream, a catalyst-enriched stream and a stream enriched in methylglutaronitrile (MGN). At least a portion of the catalyst enriched stream may be recycled to the hydrocyanation reaction. 3-pentenenitrile may be recovered and, optionally, further reacted with HCN to make adiponitrile (ADN).