Patent ID: 7282600

Claim:
A process for recovery of at least one of acrylonitrile, methacrylonitrile, acetonitrile, and hydrogen cyanide, formed by catalytic ammoxidation of propane, propylene or isobutylene with ammonia and a gaseous source of dioxygen which process comprises: providing an aqueous solution comprising acrylonitrile or methacrylonitrile, hydrogen cyanide and other organic co-products; fractionating the aqueous solution as by distillation in at least a first multi-stage column and a second multi-stage column; and maintaining within the columns an effective polymerization inhibiting amount consisting of at least one compound represented by the formula: wherein Ph is a phenylene group, and R 1 and R 2 are the same or different and are hydroxyl free organic alkyl moieties having about 2 to about 10 carbon atoms with the proviso that neither R nor R 2 is a phenyl group.