Effect of Dimethyl Disulfide on Activity of NiMo Based Catalysts Used in Hydrodeoxygenation of Oleic Acid

Alumina supported NiMo catalysts were synthesized. The prepared NiMo catalysts were activated by DMDS in a sulfidation process and characterized. The sulfided NiMo catalysts were next used in hydrodeoxygenation (HDO) of oleic acid in a batch reactor. Afterward, the NiMo catalysts were recovered and used in another set of HDO reactions of oleic acid under the same conditions used in the previous HDO reactions. After the HDO experiments, the active phase and deposited coke on spent catalysts were characterized. The results indicated that higher concentrations of DMDS promoted the production of heptadecane (C-17) but had no effect on the production of octadecane (C-18). Moreover, the XPS results revealed the promotional effect of DMDS concentration on maintenance of the sulfidity of the catalysts. In addition, the results for the experiments with the second run catalyst revealed a clear deactivation due to increased coke depositions. Furthermore, after two repeated experiments with first run and second run catalysts, it was observed that coke formation decreased when the concentration of DMDS was increased. These results dearly indicate a correlation between the concentration of DMDS and coke formation