2719. ------. [PRUDHOMME, E. A.] (L. H. Roman). Formaldehyde. United States Patent 2,000,096, May 7, 1935; appl. filed July 20, 1931, Serial No. 551,976. Chem. Abs., vol. 29, 1935, p. 4029.

Current of gas containing essentially H₂ and CO is passed, at a temperature of 130°-200°, through a hydrogenation catalyst of the Ni group of the periodic system until the catalyst becomes polarized by polymerization of aldehydes formed; depolarization is effected with a current of N₂.