Patent ID: 8329944

Claim:
A carbonylation process for producing acetic acid comprising: (a) carbonylating methanol or its reactive derivatives in the presence of a homogeneous Group VIII metal catalyst and methyl iodide promoter to produce a liquid reaction mixture including acetic acid, water, methyl acetate and methyl iodide; (b) feeding the liquid reaction mixture at a feed temperature to a flash vessel which is maintained at a reduced pressure; and (c) heating the flash vessel while concurrently flashing the reaction mixture to produce a crude product vapor stream; wherein the reaction mixture composition, the flow rate of the reaction mixture to the flash vessel, and the amount of heat supplied to the flash vessel are controlled such that the temperature of the crude product vapor stream, as measured at a vapor outlet of the flash vessel, is maintained at a temperature less than 90° F. cooler than the feed temperature of the liquid reaction mixture fed to the flasher and the concentration of acetic acid in the crude product vapor stream is greater than 70% by weight of the crude product vapor stream.