Patent ID: 7820855

Claim:
A carbonylation process for producing acetic acid comprising: (a) carbonylating methanol or its reactive derivatives in the presence of a rhodium 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 to a flash vessel which is maintained at a reduced pressure; (c) heating the flash vessel while concurrently flashing the reaction mixture to produce a crude product vapor stream, wherein the reaction mixture is selected and the flow rate of the reaction mixture to the flash vessel as well as the amount of heat supplied to the flash vessel is controlled such that the temperature of the crude product vapor stream is maintained at a temperature of greater than 300° F., as measured as close as practical to a vapor outlet of the flash vessel, and the concentration of acetic acid in the crude product vapor stream is greater than 70% by weight of the stream.