Process for producing carboxylic acids and/or esters thereof

Claim 1

A process for producing a carboxylic acid and/or its ester, which comprises reacting an alcohol selected from the group consisting of an aliphatic alcohol having 1 to 20 carbon atoms and an aromatic alcohol having 7 to 20 carbon atoms, or an ether selected from the group consisting of an aliphatic ether having 2 to 30 carbon atoms and an aromatic ether having 7 to 30 carbon atoms, with carbon monoxide in the presence of (1) elemental nickel or a nickel compound, (2) an organic nitrogen compound selected from the group consisting of (a) a compound of the formula ##STR3## wherein R 1 , R 2 and R 3 are identical or different and each represents hydrogen, alkyl or aryl, (b) a heterocyclic compound of trivalent nitrogen, and (c) a nitrile, and (3) iodine or an iodine compound selected from the following formulae (I) to (IV), RX.sub.n (I) wherein R represents a hydrogen atom or an alkyl or alkylene group, X represents an iodine or bromine atom, and n is an integer of 1 to 3, at least one of n·X's being an iodine atom, I.sub.2 or I.sub.3 - (II) RCOI (III) wherein R represents an alkyl group, MI.sub.2 (IV) wherein M represents an alkaline earth metal; the amount of the iodine or iodine compound being such that the amount of the free iodine or iodine compound not chemically bonded to the nickel or nickel compound or the organic nitrogen compound is at least 0.2 mole as elemental iodine per mole of each of the organic nitrogen compound and the nickel or nickel compound; the reaction being carried out at a carbon monoxide partial pressure of from 4 to 70 kg/cm 2 ·G.