RHODIUM / INORGANIC IODIDE CATALYTIC SYSTEM FOR METHANOL CARBONILATION PROCEDURE WITH IMPROVED IMPURITY PROFILE.

摘要

A process for producing acetic acid by reacting methanol with a source of carbon monoxide in a carbonylation reactor in which there is a reaction medium that contains a catalytically effective amount of rhodium and whose process comprises: maintaining in said reaction a medium during the course of said reaction with at least a finite concentration ranging from 0.1% by weight to less than 14% by weight of water together with: (a) a salt soluble in the reaction medium at the reaction temperature in an operational amount to maintain a concentration of ionic iodide in the range of 2 to 20% by weight effective as a catalytic and copromotor stabilizer, (b) 1 to 20% by weight of methyl iodide, (c) of 0, 5 to 30% by weight of methyl acetate, (d) a partial pressure of hydrogen between 0.68 kPa and 24.1 kPa under reaction conditions comprising 15 to 40 atmospheres (1.5 MPa at 4.0 MPa) reaction pressure to such and the concentration of hydrogen in the carbon monoxide that feeds the carbonylation reactor ranges between 0.001 mole percent and 0.3 mole percent, (e) a rhodium concentration of at least 500 ppm weight based on weight of the metallic rhodium in the reaction mixture; and (f) acetic acid.