A process for producing a high-purity acetonitrile product from a low-purity acetonitrile feedstock streams. In particular, the present disclosure relates to a process for producing a sales-grade, high purity acetonitrile by (a) distilling the feedstock stream in a to yield a crude acetonitrile stream, (b) treating the crude acetonitrile stream to produce an intermediate acetonitrile stream, (c) purifying the intermediate acetonitrile stream in a pressure swing distillation system to produce a recycle stream and an acetonitrile product stream, (d) recycling the recycle stream to the first distillation column, and (e) distilling the acetonitrile product stream to yield a purified acetonitrile product stream of at least 98 wt. % acetonitrile.