703.    DOBYCHIN, D. P., ROGINSKIĬ, S. Z. AND TSELLINSKAYA, T. F.  [Increasing the Activity of Nickel Formate Catalysts.]  Jour. Phys. Chem. (U.S.S.R.), vol. 13, 1939, pp. 1367-1388; Chem. Abs., vol. 35, 1941, p. 373.

     Activities of Ni(CHO₂)₂ catalysts obtained at various temperatures , 150°-300° in vacuo and in a stream of H₂, were determined by means of the I numbers of the oils obtained by hydrogenation in their presence.  Catalysts obtained in a stream of H₂ were as much as 5 times as active as those obtained in vacuo.  Up to 245°, a higher temperature yields a more active catalyst, 2-3 fold at 220°-245°; further heating again yields less active catalysts because of rapid aging.  The temperature should be brought up to the optimum as rapidly as possible.  Similar results should be found for other catalysts produced by endothermic reactions.  Catalysts prepared from Ni(HCO₂)₂ suspended in oil are more active than those prepared from the dry salt; the oil produces a more disperse catalyst by hindering recrystallization and sintering.  Experimental data under various conditions and the activity of catalysts obtained are shown in 9 tables and 17 figures.  IN the initial stages the rate is given by the equation for a topochemical reaction, ³√ p=a+βt.  After a surface layer of Ni covers the formate crystal, the rate of decomposition is given by v =k(a-x) 2/3.  For decomposition in oil, the initial rate is given by v=At³-Bt⁴.