3142.     SCHWAB, G. M., AND SCHWAB-AGALLIDIS, E.  [Alloys as Catalysts.]  Naturwissenschaften, vol. 31, 1943, pp. 322-323; Chem. Abs., vol. 38, 1944, p. 1679.

        Effect of separation of phases in alloys on their catalytic effect was studied.  An alloy of Al with 9.7 at. % Ag has the homogenous δ phase above 490°; below this temperature it has the hexagonal γ phase.  This change of phases, however, does not affect the catalytic effect of the alloy on decomposition of EtOH above and below 490°.  The heat of activation of the reaction with the alloy was 25-26 kcal.; that on the separately prepared pure γ phase, 28 kcal.  The same holds for MeOH decomposition.  Any effect of C on the surface is considered improbable.  With the decomposition of HcO₂H over Cu-Ag catalysts, it appeared that the heat of activation changed from 18 kcal. for pure Ag to 24 for Cu; it was 24 for 5 at. % Ag, and 20.2 for 7.5 at % Cu.  The method used was direct determination of gas flow (H₂ and CO₂) resulting from the vapor-phase reaction.  Results by a static method agreed with the above.  A simple mixing rule seems to hold.