above listed components could also be purified processed the product of the purification step is a stream generally containing methanol methyl acetate acceptable level of impurities essentially no polymer solids and sufficiently low amounts of water the impurities or amounts thereof as well as the water concentration can vary based on the desired application and the equipment in use typically for methyl acetate to be used in a methanol carbonylation unit for production of acetic acid it is recommended that no more than about one molecular unit of water per molecular unit of methyl acetate be present in the stream the invention will be described with more particularity in relation to the production of acetic acid from polyvinyl alcohol but it is recognized by those of skill in the art that production of acetic anhydride or coproduction of acetic acid and acetic anhydride can also be produced from the methyl acetate formed acetic acid anhydride or coproduction of each may be produced by a variety of methods well known in the art the present invention is not directed with the manner of making the acid or coproduction of acid and anhydride but with the integrated process allowing use of a purified or treated methyl acetate when acid anhydride or coproduction of each is produced by the method of methanol carbonylation either employing rhodium or iridium as a catalyst water and impurity levels in the methyl acetate are a concern this is because the rate of generation of water by methanation of the methanol and or reactive derivative in the carbonylation reactor is relatively high and can be greater than the.