437.    CARPENTER, H. C. H., AND SMITH, C. C.  Some Experiments on the Reaction Between Pure Carbon Monoxide and Pure Electrolytic Iron Below the A Inversion.  Jour. Iron Steel Inst., vol. 98, 1918, pp. 139-197; Chem Abs., vol. 12, 1918, p. 2523.

                   Experiments with electrolytic Fe were all conducted in a quartz tube.  The reaction temperature was 650° in all except the 1^st few experiments.  The tube was heated by enclosing it in another quartz tube, which was wound with Ni-Cr wire and suitably packed in a heat-insulating medium.  The total impurities in the Fe amounted to only 0.033%.  The CO was prepared by dropping pure HCOOH on concentrated H₂SO₄.  Special precautions were taken with regard to all the other reagents used.  The data obtained from the experiments indicate that the reaction between CO and Fe at 650° is of a complex nature and it was not possible to reach a conclusion as to the precise change or changes.  It was demonstrated, however, that a substance is formed that appears to be Fe₂C.  The presence of enough CO₂ in the gas prevents the formation of this substance.  The addition of H₂ to CO favors the production of the carbide.  In most cases, carbonaceous products are formed containing Fe, C, and O.