Synthesis of carboxylic acids

Carboxylic acids are prepared by reacting olefinic compounds with carbon monoxide in the presence of an organic sulphonic acid catalyst, and treating the product with water to produce a carboxylic acid. Olefinic compounds are where R1 is hydrogen, an aliphatic group (1-18 C), or a phenyl group, R2 is hydrogen, halogen or aliphatic group (1-6 C), R3 is hydrogen, halogen, or aliphatic group (1-6 C), and R4 is hydrogen or aliphatic (1-6 C), and with the two central carbon atoms R1 and R3 may form an alicyclic ring (6-12 C). Aliphatic sulphonic acids, e.g. D-camphor-10-sulphonic acid, methane sulphonic acid and those derived from the sulphonation of paraffins, and aromatic sulphonic acids, e.g. benzene sulphonic, benzene meta-disulphonic and naphthalene sulphonic acid, p-toluene sulphonic acid, cumene sulphonic acid, and dodecylbenzene sulphonic acid are mentioned and may be used alone or with sulphuric or phosphoric acids. Olefines mentioned are the tetramer of propylene, the dimer of isobutylene, 1-decene, 1-dodecene, 1-hexadecene, 1-octadecene, squalene, cyclohexene, 1,5-cyclooctadiene, 1,5,9-cyclododecatriene limonene and 1,2-dichloroethylene.