WS2 catalysts from tetraalkyl thiotungstate precursors and their concurrent in situ activation during HDS of DBT

The synthesis of tetraalkylammonium thiotungstates (R4N)(2)WS4 {R-4 = tetraheptyl or cetyltrimethyl}, using an aqueous solution method is reported. Tetraheptylammonium thiotungstate and cetyltrimethylammonium thiotungstate were synthesized and characterized using FTIR, UV, and TGA-DTA. These thiosalts precursors were in situ-activated concurrently during hydrodesulfurization (HDS) of dibenzothiophene (DBT), producing WS2 catalysts. These catalysts were analyzed by X-ray diffraction and surface area. The nature of the alkyl group affects both the surface area and the HDS selectivity. The X-ray diffraction study showed that the catalysts are poorly crystalline, with a very weak intensity of (002). (C) 2003 Elsevier Inc. All rights reserved.