Patent ID: 8242040

Claim:
A process for the liquid phase carbonylation of a carbonylatable reactant selected from the group consisting of methanol and reactive derivatives thereof to produce a carbonylatable product selected from the group consisting of acetic acid, acetic anhydride and mixtures thereof, which process comprises contacting, in a reaction zone, the carbonylatable reactant with carbon monoxide in a liquid reaction composition, said liquid reaction composition comprising a carbonylation catalyst selected from the group consisting of iridium, rhodium and mixtures thereof; methyl iodide, an alkali metal or alkaline earth metal salt capable of generating iodide ions and corrosion metal contaminants, in which process the liquid reaction composition is separated in a flash separation zone to obtain a vapor fraction comprising the carbonylatable product and a liquid fraction comprising a carbonylation catalyst solution wherein said carbonylation catalyst solution comprises the carbonylation catalyst, the alkali or alkaline earth metal and the corrosion metal contaminants and wherein at least a portion of the carbonylation catalyst solution is recycled to the reaction zone, wherein the carbonylation catalyst solution recycled to the reaction zone has a reduced corrosion metal contaminant content and the concentration of alkali metal or alkaline earth metal in the liquid reaction composition is controlled by contacting at least a portion of the carbonylation catalyst solution with a cation exchange resin having its active sites partially loaded with a sufficient amount of lithium or sodium, wherein the lithium or sodium loading on the resin is >0 to 60% of the resin active sites.