3001.     SABATIER, P., AND SENDERENS, J. B.  [Direct Hydrogenation of Oxides of Carbon in Presence of Various Finely Divided Metals.]  Compt. rend., vol. 134, 1902, pp. 689-691; Bull. soc. chim., vol. 29, III, 1903, p. 294; Jour. Chem. Soc., vol. 82, II, 1902, p. 317.

        Although CO is converted completely into CH₄ by H₂ in the presence of finely divided Ni at 250°, at 280° another reaction becomes obvious, the formation of CO₂ and finely divided C.  Thus, at 280°, CO and H₂ (1:3) yield a gaseous mixture, which consists of CO₂, 10.5; CH₄, 67.9; H₂, 21.6%; whereas, when equal volumes of CO and H₂ (water gas) are used, 52.5% CO₂, 39.8 CH₄, 7.1 H₂, and 0.6 CO are formed.  Co resembles Ni in its action on mixtures of CO₂ and H₂ and on CO and H₂ but is less energetic; the reduction of CO₂ begins at 300° and is rapid at 360°-400°; no formation of C or CO and no oxidation of the metal occur.  CO begins to be reduced at 270°, but at 300° the formation of CO₂ and C also is noticeable; the latter reaction plays a more prominent part the higher the temperature and the greater the proportion of CO in the mixture of this gas and H₂, that is led over the Co.  Pt sponge and Pt black, Pd sponge and reduced Fe do not bring about reduction of the oxides of C.  Reduced Cu converts a mixture of H₂ and CO₂ into CO and H₂O at 430°.