Production of acetic acid by carbonylation of methanol catalysed by iridium in the presence of a bis-phosphonate promoter

摘要

Process for obtaining acetic acid by carbonylation of methanol in the presence of an iridium catalyst, a methyl iodide co-catalyst and a bis-phosphonate promoter. Acetic acid is produced by carbonylation with CO of methanol and/or a reactive derivative in a carbonylation reactor. The reactive composition comprises an Ir catalyst, a MeI co-catalyst and a final concentration of water, acetic acid, methyl acetate and promoter. The water concentration is at or below that at which the maximum occurs in the graph of velocity of carbonylation as a function of concentration. The reaction liquid is free from a promoter comprising Ru, Os, W, Rh, Zn, Ga, Cd or In, but contains a bis-phosphonate conforming to formula (I); R1, R2, R3, R4 = H or an organic group; Y = 1 - 10C alkylene or 6 - 10C aryl(optionally substituted).