Patent ID: 6107509
Filing Date: 2000-08-22
Classification: C07C

Abstract:
A process for the manufacture of an unsaturated mononitrile selected from the group consisting of acrylonitrile and methacrylonitrile comprising transporting a reactor effluent containing the unsaturated mononitrile to a first column where the reactor effluent is cooled with a first aqueous stream, transporting the cooled effluent containing the unsaturated mononitrile into a second column where the cooled effluent is contacted with a second aqueous stream to absorb the unsaturated mononitrile into the second aqueous stream, transporting the second aqueous stream containing the unsaturated mononitrile from the second column to a first distillation column for separation of the crude unsaturated mononitrile from the second aqueous stream, and transporting the separated crude unsaturated mononitrile to a second distillation column to remove at least some impurities from the crude mononitrile, and transporting the partially purified crude unsaturated mononitrile to a third distillation column to further purify the crude unsaturated mononitrile, recovering the purified unsaturated mononitrile in a sidestream from the third distillation column, introducing about 100 to about 2000 ppm of water in the form selected from the group consisting of steam, distilled water and mixtures thereof into the bottom stream obtained from the third distillation column and recycling at least part of the bottom stream obtained from the third distillation column to the bottom portion of the third distillation column.