Process for the preparation of carboxylic acids from organic halides

A process for the preparation of carboxylic acid by reaction of carbon monoxide with an organic halide selected from the group consisting of aromatic and aliphatic halides, and catalyzed by a phosphine palladium complex selected from the group consisting of (a) a palladium complex of the formula Pd[P(R).sub.3 ].sub.m wherein m is a whole number from 2 to 4, and (R).sub.3 represents a homogeneous or heterogeneous group consisting of phenyl and alkyl radicals;

• (b) a palladium complex of the formula Pd[P(R).sub.2 --(CH.sub.2).sub.n --P(R.sub.2)].sub.p wherein (R).sub.2 has the same meaning indicated above for (R).sub.3, p is a whole number from 1 to 2, and m is a whole number from 1 to 6;
• or (c) a palladium complex of the formula ##STR4## wherein the groups (R).sub.3, equal to or different from each other have the same meaning as indicated above, and Y is a halogen atom and an aryl radical
• and in the presence of a quaternary alkyl-ammonium salt having a total of at least 6 carbon atoms, characterized in that said process is conducted in a double liquid phase consisting of (a) said organic halide and said catalytic palladium complex or their solutions in a hydrocarbon solvent immiscible with H.sub.2 O, and (b) an aqueous sodium hydroxide or potassium hydroxide solution containing said quaternary alkyl-ammonium salt
• at a temperature between about 50.degree. C. and 150.degree. C., the molar ratio of Pd/organic halide being between 0.1 and 0.0001 and the molar ratio of sodium or potassium hydroxide/organic halide being greater than equimolar, and
• acidifying the resulting intermediate product to obtain said carboxylic acid.