The present invention relates to the preparation of a carboxylic acid from an alcohol, particularly by a carbonylation reaction.
Carbonylation or carboxylation reactions wherein olefins are reacted with carbon monoxide and water have long been known. See, for example, U.S. Pat. No. 1,924,766 to Carpenter. U.S. Pat. No. 1,940,674, also to Carpenter, discloses reaction of an alcohol with carbon monoxide to form a carboxylic acid. U.S. Pat. No. 2,658,075 to Reppe et al refers to the carbonylation reaction with olefins as follows:
"It is well known that carboxylic acids or their functional derivatives may be obtained by treating olefins with carbon monoxide and compounds containing a replaceable hydrogen atom, such as water, alcohols, mercaptans, ammonia or primary or secondary amines or carboxylic acids. This process is generally called carbonylation."
See also U.S. Pat. No. 3,282,993, entitled "Carbonylation Process", which briefly discusses the Koch reaction wherein an olefin is reacted only with CO to form an internal anhydride which is subsequently hydrolyzed to the acid. U.S. Pat. No. 3,176,585 refers to the reaction of olefin with carbon monoxide and water as carboxylation rather than simply as carbonylation.
The present invention is particularly concerned with the carbonylation of an alcohol. Tsuji et al, "Catalytic Carbonylation of Allylic Compounds with Palladium Chloride", J. Am. Chem. Soc. 86, (1964), pp. 4350-4353 (see also Tsuji et al, U.S. Pat. No. 3,427,344) disclose the reaction of allyl alcohol with carbon monoxide in the presence of a palladium chloride catalyst. The products formed include ethyl-3-butenoate in 42% yield when the reaction is carried out in an ethanol solvent, and 3-butenoic anhydride in 19% yield when the reaction is carried out in a benzene solvent. Tsuji et al do not show formation of 3-butenoic acid.
Carbonylation of olefins in alcoholic solvent to carboxylic acid esters in the presence of palladium compounds is described by K. Bittler et al (Angew. Chem. Internat. Edit., 1(5), 329, 1968). In one example, allyl alcohol was converted to methyl 3-butenoate in 65% yield. In order to convert this product to 3-butenoic acid, which is preferred for certain applications, additional processing steps are required, i.e., hydrolysis and purification.
A laboratory synthesis of 3-butenoic acid is described in Org. Synthesis 24,29 (1944). In this synthesis, allyl chloride is converted to 3-butenenitrile with CuCN, which is then hydrolyzed by concentrated HCl to 3-butenoic acid in about 60% over-all yield.