HDS of DBT with Molybdenum Disulfide Catalysts Prepared by In Situ Decomposition of Alkyltrimethylammonium Thiomolybdates

Three alkyltrimethylammonium thiomolybdates, [R-N(CH(3))(3)](2)MoS(4) (where R = lauryl, myristyl or cetyl) were synthesized in aqueous solution, and characterized by (1)H-NMR spectroscopy. These alkyltrimethylammonium thiomolybdates were used (the lauryl and myristyl thiomolybdates for the first time) as precursors for in situ prepared MoS(2) catalysts, activated during the hydrodesulfurization of dibenzothiophene. The catalysts were analyzed by EDX, showing large voids and a S/Mo ratio around 2. High surface areas up to 443 m(2)/g and type IV adsorption-desorption nitrogen isotherms were obtained. X-ray diffraction showed that the catalysts are poorly crystalline, with a very weak (002) peak intensity for all samples except the MoS2 catalyst prepared from pure ammonium tetrathiomolybdate precursor. A high dibenzothiophene conversion (74%) was observed with the catalyst obtained from the lauryltrimethylammonium thiomolybdate precursor, attributed mainly to its high specific surface area. Selectivity results showed that all the prepared catalysts strongly favored the hydrogenation pathway.