2676.     ---------------.  [PICHLER, H.]  [Reaction of Carbon Dioxide During Hydrogenation.]  Brennstoff-Chem., vol. 24, 1943, pp. 39-40; Chem. Zentralb., 1943, I, p. 2556; British Chem. Abs., 1944, B, p. 194; Chem. Abs., vol. 37, 1943, p. 6526.

        In the Fischer-Tropsch synthesis, CO₂ does not react in the presence of CO; atomic H is assumed to be necessary for the hydrogenation of CO₂.  Only little chemisorbed H₂ is present on the catalyst surface during the formation of higher hydrocarbons.  The hydrogenation of CO₂ does not follow the same course as that of CO.  HCOOH may be considered the first intermediate product in the hydrogenation of CO₂ and it is converted isomerically into dioxymethylene.  The next stage is CHOH with liberation of H₂O from which CH₄ or MeOH is formed according to the reaction conditions.