858. ------. [GRESHAM, W. F.] (E. I. du Pont de Nemours & Co.). Synthesis of Carboxylic Acids. United States Patent 2,432,474. Dec. 9, 1947. Chem. Abs., vol. 42. 1948, p. 1961.

Patent Abstracts

Carboxylic acids are prepared by the reaction of a polyalkylene cyclic monoether with CO in the presence of a Ni carbonyl catalyst. Thus, NiCl₂.6 H₂O. 23.8; Ni(CO)₄, 17.1; tetrahydrofuran, 72.1; and H₂O. 70.3 gm. are heated in a Cu-lined shaker tube at 290º-315ºwith CO at 740-800 atm. The ether extract of the reaction mixture is fractionated to yield 31.9 gm. of an acid fraction b₂₈75º-97º, neutralization equivalent 106; 17.8 gm. acid b1 up to 131º: and 6.4 gm. solid acidic residue. The main fraction is resolved by redistillation into EtCHMeCO₂H and BuCO₂H.