3105.     SCHRADER, H.  [Production of Formic Acid From Carbon Monoxide and Steam, and From Carbon Dioxide and Hydrogen, at High Temperatures and Pressures.]  Ges. Abhandl. Kenntnis Kohle, vol. 6, 1921, pp. 65-78; Chem. Abs., vol. 19, 1925, p. 36.

        By heating 20 cc. of water with Co under 135 atm. pressure in Fe autoclaves, 14.2 and 7.2 cc. of 0.1 N HCO₂H were obtained at 350° and 400°, respectively, while the residual gases contained, respectively, 14.0% and 28.0% of CO₂.  Considerable quantities of Fe carbonyl were in the solution.  On using a Cu-lined autoclave, the quantity of HCO₂H produced increased successively from 5.55 cc. to 14.4 cc. of 0.1 N solution in 5 experiments, and the CO₂ content of the residual gases fell 34.1-4.2%.  Apparently some impurity with a harmful catalytic action was removed gradually from the apparatus or was rendered inactive; these results, however, could not always be repeated.  Only small quantities of formic acid could be obtained in autoclaves lined with Ag, and, moreover, the residual gases contained but little CO₂.  The action of Fe and Cu agrees with observations by Armstrong and Hildtich (abs. 76).  The hydrogenating action of CO and steam upon coal (see abs. 749 and 750, Part I, of Bibliography of Pressure Hydrogenation, Bureau of Mines Bull. 485), apparently depends upon the intermediate formation of HCO₂H.  In the thermal decomposition of HCO₂H at 400° under 120 atm. pressure in Cu autoclaves, the proportion remaining undecomposed was approximately the same as that produced from CO and steam, but, at 300°, the proportion undecomposed was somewhat greater than that formed at the same temperature.  The formation of HCO₂H from a mixture of CO₂ under 30 atm. and H₂ under 50 atm. pressure was much greater in Fe than in Cu autoclaves.  In the presence of Na₂CO₃, the yield of 0.1 N HCO₂H was 78.3 cc. at 350°.  H₂ and Na₂CO₃ solution, on heating in Fe autoclaves, yielded 15.7 cc. of 0.1 N, HCO₂H, but none was obtained in Cu autoclaves.