Mixture of O2 and H2O vapor, not >1 vol. of O2 to 2 vol. of H2O vapor, is passed over C at a temperature not execeeding 750° and CO2 is removed to obtain a mixture containing H2, 2 and CO, 1 vol. By preheating the O2 and H2O vapor and using a temperature <700°, a mixture of H2, 3 and CO, 1 vol. is obtained. Pressures up to 20 atm. may be used, and the gas mixtures obtained may be used for the synthesis of hydrocarbons, MeOH, and other O-containing organic compounds.