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US 4,362,603 AGranted
Continuous acetonitrile recovery process
AssigneeThe Standard Oil Company
InventorsRobert D. Presson, Hsin-Chih Wu, Edward J. Sockell
Life of this patent
Estimating the term…
Abstract
Crude acetonitrile is purifed to 99+ weight percent by a continuous distillation procedure.
Claims12
A continuous process for recovering highly pure acetonitrile from crude acetonitrile by-produced during amoxidation of propylene containing acetonitrile, water, HCN and heavy organics, said process comprising:
- (1) distilling said crude acetonitrile in a first distillation zone at a first pressure at or above 1 atmosphere to remove HCN therefrom and produce a first acetonitrile/water azeotrope and a first bottoms product containing water,
- (2) distilling said first azeotrope in a second distillation zone at a second pressure less than 1 atmosphere to separate said first azeotrope into a second bottoms product containing water and a second acetonitrile/water azeotrope having a greater acetonitrile concentration than said first azeotrope, and
- (3) distilling said second acetonitrile/water azeotrope in a third distillation zone at a third pressure above 1 atmosphere to produce a third acetonitrile/water azeotrope containing substantially all of the water in said second azeotrope, third bottoms product comprising acetonitrile and heavy organics and a sidestream comprising said highly pure acetonitrile of at least 95%.
A process for recovering highly pure acetonitrile from a first acetonitrile/water mixture by-produced during amoxidation of propylene containing about 15 weight percent or more water comprising:
- (1) distilling said first mixture in a first distillation zone at a first pressure below 1 atmosphere to produce a water-containing bottoms product and a second acetonitrile/water mixture comprising an azeotrope of acetonitrile and water more concentrated in acetonitrile than said first mixture,
- (2) distilling said second mixture at a second pressure above 1 atmosphere to produce a third acetonitrile/water mixture comprising an azeotrope of acetonitrile and water less concentrated in acetonitrile than said second mixture and said highly pure acetonitrile of at least 95%, and
- (3) recycling said third mixture so that said third mixture is distilled along with said first mixture.
Dependencies are inferred from the claim text.