Process for producing acetic acid

A process for producing acetic acid, comprising the steps of:

• (a) reacting carbon monoxide with at least one reactant selected from the group consisting of methanol, methyl acetate, methyl formate, dimethyl ether and mixtures thereof in a reaction medium comprising water, methyl iodide, and a catalyst to produce a reaction product comprising acetic acid;
• (b) performing a vapor-liquid separation on said reaction product to provide a volatile phase comprising acetic acid, water, and methyl iodide and a less volatile phase comprising said catalyst;
• (c) distilling said volatile phase to produce a purified acetic acid product and a first overhead comprising water, methyl acetate, and methyl iodide;
• (d) phase separating said first overhead to provide a first liquid phase comprising water and a second liquid phase comprising methyl iodide;
• and
• (e) adding dimethyl ether to the process in an amount effective to enhance separation of the first overhead to form the first and second liquid phases.