Acrylonitrile and methacrylonitrile recovery and purification system

Claim 2

IN THE PROCESS FOR THE RECOVERY AND PURIFICATION OF ACRYLONITRILE OR METHACRYLONTRILE OBTAINED BY THE AMMOXIDATION OF PROPYLENE OR ISOBUTYLENE WHEREIN A. THE REACTOR EFFLUENT IS DIRECTLY CONTACTED WITH AN AQUEOUS STREAM TO COOL THE GASES IN A QUENCH COLUMN, B. THE ACRYLONITRILE AND HCN ARE RECOVERED IN THE FORM OF AN AQUEOUS SOLUTION, C. SOME OF THE WATER AND IMPURITIES ARE REMOVED BY DISTILLATION TO FORM A CONCENTRATED AQUEOUS MIXTURE OF ACRYLONITRILE AND HCN,

Claim 3

The process of claim 1 wherein the HCN in the HCN distillation column is stabilized with acetic acid.

Claim 4

The process of claim 1 wherein acrylonitrile is recovered and purified.

Claim 5

In the process for the recovery and purification of acrylonitrile or methacrylonitrile obtained by the ammoxidation of propylene or isobutylene wherein a. the reactor effluent is directly contacted with an aqueous stream to cool the gases in a quench column; b. the acrylonitrile and HCN are recovered in the form of an aqueous solution; c. some of the water and impurities are removed by distillation to form a concentrated aqueous mixture of acrylonitrile and HCN; d. the aqueous mixture of acrylonitrile and HCN is distilled in an HCN distillation column to remove the HCN in an overhead stream; and e. the bottoms in the HCN distillation column are fed to a decanter where an aqueous layer and an organic layer are formed, the improvement comprising removing the aqueous layer from the decanter and recycling the aqueous layer to the quench column where it is directly contacted with the reactor effluent.

Claim 6

In the process for the recovery and purification of acrylonitrile or methacrylonitrile obtained by the ammoxidation of propylene or isobutylene wherein a. the reactor effluent is directly contacted with an aqueous stream to cool the gases in a quench column; b. the acrylonitrile and HCN are recovered in the form of an aqueous solution; c. some of the water and impurities are removed by distillation to form a concentrated aqueous mixture of acrylonitrile and HCN; d. the aqueous mixture of acrylonitrile and HCN is distilled in an HCN distillation column to remove the HCN in an overhead stream; and e. the bottoms in the HCN distillation column are fed to a decanter where an aqueous layer and an organic layer are formed, the improvement comprising removing the aqueous layer from the decanter and recycling the aqueous layer to the quench column where it is directly contacted with the reactor effluent.

Claim 7

The process of claim 4 wherein the HCN in the HCN distillation column is stabilized with acetic acid.

Claim 8

The process of claim 4 wherein acrylonitrile is recovered and purified.