Production of acetic acid with enhanced catalyst stability

摘要

Processes for the production of acetic acid by carbonylation of methanol and reactive derivatives thereof in a liquid phase reaction medium, wherein the reaction medium comprises a finite amount of water, a homogeneous catalyst, an alkyl halide promoter, and a catalyst stabilizer/co-promoter comprising an imidazolium cation R1R2Im+ as an iodide salt, wherein R1 and R2 are each independently a substituted or unsubstituted alkyl or cycloalkyl, with the proviso that R1 and R2 are not the same.

主权项

1. A process for producing acetic acid, the process comprising the steps of:
reacting carbon monoxide with at least one reactant selected from the group consisting of methanol, methyl acetate, methyl formate, dimethyl ether and mixtures thereof in a reactor containing a reaction medium to produce a reaction product comprising acetic acid, wherein the reaction medium comprises a finite amount of water, a homogeneous catalyst, an alkyl halide promoter, and a catalyst stabilizer comprising a dissymmetric imidazolium cation R1R2Im+as an iodide salt, wherein R1 and R2 are each independently a substituted or unsubstituted alkyl or cycloalkyl, with the proviso that R1 and R2 are not the same; and maintaining the reaction medium at a total iodide ion concentration of from 2 to 35 wt. % and an alkyl halide promoter concentration of greater than 1 wt. %, based on the total weight of the reaction medium.