Production of acrylic nitrile

Claim 1

IN A PROCESS FOR OBTAINING ACRYLIC NITRILE FROM THE REACTION OF ACETYLENE WITH HYDROCYANIC ACID IN THE PRESENCE OF AN AQUEOUS SOLUTION OF A CUPROUS SALT FOLLOWED BY WATER WASHING OF THE RESIDUAL GASES OF REACTION, THAT IMPROVEMENT, WHICH COMPRISES INTRODUCING THE MIXTURE OF REACTION VAPORS CONTAINING ACRYLIC NITRILE, ACETYLENE, VINYLACETYLENE AND DIVINYLACETYLENE WITH STREAM AT A TEMPERATURE BETWEEN 70-100 C. AT THE BASE OF A RECTIFYING COLUMN FED AT THE TOP WITH WASH WATER, THE FLOW AND TEMPERATURE OF THE WASH WATER AT THE TOP OF SAID COLUMN AND THE MIXTURE OF VAPORS AND STEAM AT THE BOTTOM OF THE COLUMN BEING ADJUSTED SO THAT A WATER SOLUTION OF ACRYLIC NITRILE FLOWS OUT OF THE BASE OF THE COLUMN AT A TEMPERATURE BETWEEN ABOUT 20 AND 40* C., SAID SOLUTION BEING PRACTICALLY FREE OF ACETYLENE, VINYLACETYLENE AND DIVINYLACETYLENE AND RECTIFYING THE ACETYLENE, VINYLACETYLENE, AND DIVINYLACETYLENE RESIDUAL GAS MIXTURE OBTAINED AT THE TOP OF THE RECTIFYING COLUMN IN THE PRESENCE OF A COUNTER FLOWING MINERAL OIL SOLVENT FOR VINYLACETYLENE, SAID MINERAL OIL HAVING A BOILING POINT BETWEEN 150 AND 300* C. AND WHICH IS SATURATED WITH SULPHUR, THE TEMPERATURE OF THE MINERAL OIL SOLVENT FOR VINYLACETYLENE BEING MAINTAINED NEAR THE BOILING POINT OF VINYLACETYLENE WHERE SUBSTANTIALLY PURE ACETYLENE FREE FROM VINYLACETYLENES, IS OBTAINED AT THE TOP OF THE RECTIFYING COLUMN AND A CONCENTRATED SOLUTION OF VINYLACETYLENE IS OBTAINED AT THE BOTTOM OF THE RECTIFYING COLUMN.