Abstract: A process for preparing a carboxylic acid having (n+1) carbon atoms (e.g. acetic acid) from an alcohol having n carbon atoms (e.g. methanol) by liquid phase, rhodium catalyses carbonylation is provided. The process is characterized by using a catalyst stabilizer selected from certain classes of imidazolium iodides, alkyl substituted pyridinium iodides and hydroxypyridinium iodides. Most preferred are those derived from the amines 2-ethyl-4-methyl imidazole, 4-ethylpyridine, 4-t-butylpyridine and 3,4-lutidine by quarternisation with a methyl group.

Abstract: The solubility and stability of rhodium catalysts in rhodium-catalysed carbonylation of alkyl esters or alkyl ethers under substantially anhydrous conditions to produce carboxylic acid anhydrides is improved by the use of co-promoters selected from the group:1,3-dialkyl-4-methylimidazolium iodide;1,3-dialkyl-4-ethylimidazolium iodide;1,3-dialkyl-4-n-propylimidazolium iodide;1,3-dialkyl-4-isopropylimidazolium iodide;1,3-dialkyl-4-n-butylimidazolium iodide1,3-dialkyl-4-sec-butylimidazolium iodide1,3-dialkyl-4-tert-butylimidazolium iodide;1,3-dialkyl-2,4,5-trimethylimidazolium iodide and mixtures thereof wherethe alkyl groups are independently C.sub.1 to C.sub.20 alkyl.

Abstract: A process for preparing ketones comprises reacting an alkene with carbon monoxide and a secondary alcohol at elevated temperature in the presence of a rhodium catalyst and an aminoalcohol or aminoether promoter. A preferred catalyst is Rh.sub.6 (CO).sub.16 and a preferred promoter is N(CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 OCH.sub.3).sub.3.

Abstract: A liquid phase process for preparing alpha-hydroxyketones is provided. The process comprises condensing one or more aldehydes in the presence of a thiazolium salt and a sterically hindered base having a pKa value greater than 12.0. The sterically hindered base is preferably either an amidine or a secondary or tertiary alkoxide of an alkali metal.