Abstract
Sulfurizatioin of Ni and NiS0.5 with some sulfur compounds and reduction of NiS0.8 with hydrogen have been studied kinetically.
Sulfurization rate of NiS0.5 with H2S was the 0.86th order with respect to H2S concentration and nearly independent of temperature. Kinetic orders of this process were the 0.98th and 0.82th for CS2 and thiophene respectively and activation energies were 8.0kcal/mol for CS2, and 9.6kcal/mol at lower temperature range (400-430°C) and 39kcal/mol at higher temperature range (430-460°C) for thiophene.The reactivities in sulfurization changed in the order of CS2>H2S> thiophene, which coincided with the order of desulfurizabilities by this catalyst.
Reduction rate of NiS0.8 with hydrogen was 1st order with respect to hydrogen concent ration and activation energy of this process was 15.4kcal/mol, and this reduction rate was more rapid than that of sulfurization in the concentration range of sulfur compounds below 2.8%.
From these results it was concluded that, in the case of hydrogenolysis of thiophen (<2.8%) in benzene by this catalyst the process of sulfrization of the surface was the rate determining step.
