Acrylonitrile and methacrylonitrile recovery and purification system

• US 3,885,928 A
• Filed: 06/18/1973
• Issued: 05/27/1975
• Est. Priority Date: 06/18/1973
• Status: Expired due to Term

• Current Assignee: Hsin Chih Wu
• Original Assignee: Hsin Chih Wu
• Inventors: Wu, Hsin Chih
• Primary Examiner(s): Adee, John
• Application Number:
  US05/371,043
• Time in Patent Office: 708 Days
• Field of Search: 55/82,85,89,70
• US Class Current: 95/193
• CPC Class Codes: C07C 253/34 Separation; Purification
• CPC Class Codes: C07C 255/08 Acrylonitrile; Methacrylonitrile

Abstract

In the recovery and purification of acrylonitrile or methacrylonitrile obtained by the ammoxidation of propylene or isobutylene, the aqueous layer of the decanter associated with the column removing HCN from the nitrile is recycled to the quench column wherein the hot gases from the reactor are directly contacted with the aqueous recycle stream.

Claims

1. 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,

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

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

4. 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.

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

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