METHOD FOR INHIBITING POLYMERIZATION DURING THE RECOVERY ANDPURIFICATION OF UNSATURATED MONONITRILES

摘要

Economical processes are disclosed for recovery and refining of valuable nitrogen-containing organic compounds formed by catalytic oxidation of least one feed compound selected from the group consisting of propane, propylene, isobutane and isobutylene in the presence of ammonia to produce a gaseous. Processes of the invention include quenching the gaseous reactor effluent wi th an aqueous quench liquid; forming an aqueous solution comprising the corresponding unsaturated mononitrile, hydrogen cyanide and other organic co - products; and using an integrated sequence of distillations and phase separations to recover for recycle of a useful aqueous liquid, and obtain th e desired nitrogen-containing products. According to the invention aqueous solutions are fractionated in an integrated system of multi-stage columns while an effective polymerization inhibiting amount of at least one member o f a preselected class of p~-phenylenediamine compounds is maintained therein.< /SDOAB>