Solvent effect over the promoter addition for a supported NiWS hydrotreating catalyst

- Highly active NiWS catalysts were prepared from Ni(acac)2 and tested in the HDS of 4,6 DMDBT.
- Ni(acac)2 was added directly over supported sulfided tungsten.
- Among different solvents used in the reflux, the promoting effect varied significantly.
- XPS analyses indicated that 100% of the methanol-added nickel was forming the decorated “NiWS” phase.

A series of NiWS catalysts supported on alumina was synthesized using a reflux of nickel acetylacetonate Ni(acac)2 solution over previously impregnated and sulfided tungsten. Methanol, isopropanol, acetone and toluene were used as solvents in the incorporation of Ni. The catalysts were tested in the Hydrodesulfurization of 4,6 dimethyldibenzothiophene and compared with a conventional NiWS/Al2O3 catalyst (prepared from Ni(NO3)2). UV-vis spectroscopy results showed that the interaction between the nickel atom and its environment was affected in relation to the solvent used. The Ni(acac)2 based catalysts showed up to a 3-fold increase in the reaction rate when compared with the reference catalyst. Among the solvents in the impregnation of the metal complex, methanol induced the highest specific activity, 130% higher than the catalyst prepared using toluene. XPS analyses indicated that up to 100% of the methanol-added nickel was forming the decorated “NiWS” active phase.

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