Addition of iridium to the rhodium/inorganic iodide catalyst system
AssigneeCelanese International Corporation
InventorsHung-Cheun Cheung, Elaine C. Sibrel, Robin S. Tanke, G. Paull Torrence
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Abstract
The present invention provides a process for the carbonylation of an alcohol, ether or ester to products comprising a carboxylic acid, the anhydride thereof or coproduction of the carboxylic acid and anhydride. More particularly, the present invention provides a process for the carbonylation of methanol to produce acetic acid by reacting methanol with carbon monoxide in a liquid reaction medium containing a catalyst comprising rhodium, iridium, iodide ion, and said reaction medium further comprising water, acetic acid, methyl iodide, and methyl acetate and subsequently recovering acetic acid from the resulting reaction product.
Claims12
In a process for producing acetic acid by reacting methanol with a carbon monoxide feed in a liquid reaction medium containing a catalyst comprising a rhodium salt and an iridium salt, and comprising water, acetic acid, methyl iodide, and methyl acetate and subsequently recovering acetic acid from the resulting reaction product, the improvement which comprises:
- maintaining in said reaction medium during the course of said reaction about a finite amount to less than 14 wt % of water together with (a) an effective amount of iodide ion in the range of about 2 to 20 wt % as catalyst stabilizer/co-promoter selected from the group consisting of alkali metal and alkaline earth metal salts, quaternary ammonium, phosphonium iodide salts, (b) about 5 wt % to 30 wt % of methyl iodide, and (c) about 0.5 wt % to 30 wt % of methyl acetate.
Dependencies are inferred from the claim text.