The effect of boron addition on hydrodesulfurization and hydrodenitrogenation activity of NiMo/Al2O3 catalysts

Studies of catalytic activity of a series of nickel-molybdenum catalysts su pported on Al2O3 modified with berate ions were performed for the hydrotrea ting of coal Liquid. Decomposition of isopropyl alcohol, diacetone alcohol and ethylbenzene was performed for the characterization of acidity of the c atalysts. Quinoline and carbazole hydrodenitrogenation (HDN) were used as t est reactions. It was found that modification of the support with berate io ns increases the acidity of nickel-molybdenum catalyst, in particular, the amount of acidity centers of intermediate strength. However, although the m odification practically does not affect the hydrosulfurization activity of coal Liquid, it considerably affects its HDN activity. In the latter case, it leads to an increase in the resistance to coking of the modified catalys ts. This particularly applies to the HDN process in which the above catalys ts are still very active after a long period of run, and hence their dehydr ogenation activity rises. The high HDN activity is connected to the increas ing number of acid centers of intermediate strength. (C) 2000 Elsevier Scie nce Ltd. All rights reserved.