Patent ID: 6222070
Filing Date: 2001-04-24
Classification: B01J,C07C,Y02P

Abstract:
In a liquid phase carbonylation process for the production of acetic anhydride by reacting in a carbonylation zone a feed stream comprising methyl acetate, dimethyl ether or mixtures thereof, methanol, carbon monoxide and hydrogen using a Group VIII metal-containing catalyst and a halogen or halide containing material, wherein a liquid reaction product is continuously withdrawn from the carbonylation zone and fed to an evaporation/separation zone to separate volatile constituents of the reaction from the non-volatile constituents prior to returning the non-volatile constituents to the carbonylation zone, wherein the non-volatile constituents includes a portion of the Group VIII metal catalyst from the carbonylation reactor having a reduced catalytic activity, wherein the improvement for regenerating said Group VIII metal-containing catalyst and reducing an amount of EDA produced comprises contacting said Group VIII metal-containing catalyst with a gas stream having from 0.01 to 1.8 volume % hydrogen for a period of from about 0.001 seconds to about 200 seconds as said Group VIII metal-containing catalyst is being returned to said carbonylation zone whereby a hydrogen treated Group VIII metal-containing catalyst is obtained and re-circulated to said carbonylation zone.