Acetic acid production methods incorporating tin or ruthenium catalyst stabilizers

Abstract

Processes for the production of acetic acid by carbonylation of methanol, and reactive derivatives thereof, in a reaction mixture using a rhodium-based catalyst system with at least one catalyst stabilizer selected from the group of ruthenium catalyst stabilizers, tin catalyst stabilizers, and mixtures thereof are provided. The catalyst stabilizers minimize precipitation of the rhodium metal during recovery of the acetic acid product, particularly in flasher units in an acetic acid recovery scheme. Stability of the rhodium metal is achieved even when the acetic acid is produced in low water content reaction mixtures in the presence of an iodide salt co-promoter at a concentration that generated an iodide ion concentration of greater than about 3 weight % of the reaction mixture. The stabilizing ruthenium or tin compounds may be present in the reaction mixture for the production of acetic acid at molar concentrations of ruthenium or tin metal to rhodium of about 0.1:1 to about 20:1.

Dependencies are inferred from the claim text.