Process for preparing carboxylic acids.

摘要

An improved liquid-phase process for preparing carboxylic acids having (n + 1) carbon atoms by rhodium catalysed carbonylation of an alcohol having n carbon atoms is provided. The process is particularily suitable for preparing acetic acid from methanol in commercial carbonylation reactors operating at steady-state with a low standing quantity of water (eg 0.5 to 5% by weight). The improvement lies in carrying out the carbonylation in the presence of an iodide stabiliser (eg lithium iodide) and a Group VI B metal costabiliser. The process can optionally be carried out in the presence of hydrogen.