2528. NIELSON, H. Destructive Distillation of Coal, Wood or Similar Materials. United States Patent 1,605,761, Nov. 2, 1926; appl. filed Nov. 27, 1922. Chem. Abs., vol. 21, 1927, p. 168.

Formic acid is made from CH4 or gas containing it by passing the gas over a metallic catalyst such as Cu suboxide. The reaction is as follows: CH4+O2=CO+H2O+H2=HCOOH. It may also be made from CO in the presence of H2O vapor and the catalyst.