Elsevier

Journal of Catalysis

Volume 27, Issue 3, December 1972, Pages 357-368
Journal of Catalysis

The CoOMoO3Al2O3 catalyst. IV. Pulse and continuous flow experiments and catalyst promotion by cobalt, nickel, zinc, and manganese

https://doi.org/10.1016/0021-9517(72)90171-6Get rights and content

Abstract

The activities of MoO3Al2O3 catalysts promoted with various amounts of cobalt, nickel, zinc, and manganese have been determined in pulse and continuous flow experiments for the hydrodesulphurization of thiophene at atmospheric pressure and 400 °C. The initial activities of a MoO3Al2O3 and a CoOMoO3Al2O3 catalyst as inferred from pulse experiments are equal. Continuous flow experiments for all catalysts show that the activity decays rapidly and approaches a steady-state level that depends on the promoter and its concentration. Maximum steady-state activity levels are attained for each of the promoter ions at different metal-to-molybdenum ratios. Some models are discussed in an attempt to explain the experimental results.

A preliminary investigation of hydrogenation activity of the above-mentioned catalysts is reported. With increasing promoter content a minimum for the initial hydrogenation activity is found. Hydrocarbon saturation at the steady-state is comparatively insensitive to the nature of the promoter ion, which may be associated with the sulphiding of the surface.

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