Process for the preparation of acetic acid and acetic anhydride

Abstract From the Canadian patent

To prepare acetic acid and acetic anhydride methanol and, methyl acetate are reacted under anhydrous conditions with carbon monoxide in the presence of a catalyst system containing carbonyl complexes of group VIII noble metals methyl iodide, an alkali metal acetate or iodide or, quaternary organophosphonium or organoammonium acetate or iodide. The hot carbonylation mixture is decompressed the, evaporated components are fed to a first distillation zone and the catalyst solution which remains is fed back to the reaction zone. In the first distillation zone the volatile, carbonylation products are subjected to fractional distillation; the low-boiling methyl iodide and methyl acetate pass back …