3245.     SPINGLER, H., AND REINHARD, O.  [“Magnetocatalytic Effect” in the Hydrogenation of Carbon Dioxide of Carbon Monoxide on Nickel.]  Ztschr. physik. Chem., vol. 190, A, 1942, pp. 331-340; Chem. Abs., vol. 37, 1943, p. 4958.

        Mixture of CO or CO₂ and H₂ was passed over powdered Ni heated to temperatures near the Curie point (350°-360°) in an apparatus similar to that of Fischbeck and Salzer (abs. 938).  The amount of reaction was determined by collecting and weighing the H₂O formed and the residual CO₂.  The percent of CO₂ hydrogenated in 15 min. increased with increase in temperature, but there was no discontinuity in the curve at the Curie point.  Analogous results were obtained for decreasing temperatures.  In the hydrogenation of CO there is a decided increase in activity beginning at approximately 350° and ending at approximately 370° in a sudden decrease (abs. 1387).  The sudden decrease at 370° apparently is independent of the proximity of the Curie point; it may result from the deposition of C on the catalyst as a result of disproportionation of CO (abs. 130).  No change could be detected in the catalyst in this temperature region.  Above 370°, the curve of % hydrogenation of CO versus temperature was very irregular; this is attributed to the antagonistic effects of the activating and poisoning mechanisms.  The change in the catalytic activity of Ni in the region of the Curie point probably is not related to the Curie transformation but depends on the specific catalytic properties of the stable phase in that temperature region; hence, the existence of the magnetocatalytic or Hedvall effect is doubtful.