Relevance of sulfiding pretreatment on the performance of Re/ZrO2 and Re/ZrO2-sulfated catalysts for the hydrodeoxygenation of guayacol

The effect of the sulfiding mixture (H2/H2S and N2/H2S) over Re/ZrO2 and Re/ZrO2-sulfated catalysts in the hydrodeoxygenation (HDO) of 2-methoxyphenol (guayacol) in the presence of CS2 has been studied. The catalysts were prepared by wet impregnation and characterized by X-ray diffraction (XRD), BET surface area, X-ray photoelectron spectroscopy (XPS) and surface acidity techniques. The reaction was carried out in a batch reactor at 300 °C and 5 MPa. Reaction rates for both catalysts increased upon sulfiding in N2/H2S mixture. This N2/H2S mixture promotes the formation of ReS(2 − x) species over support surfaces and leads to an increase in the rate of direct demethoxylation and an enhancement in the phenol/cathecol ratio. An increase in the concentration of CS2 leads to an increase in the HDO and cathecol and inhibits the demethoxylation of guayacol.

Figure optionsDownload high-quality image (92 K)Download as PowerPoint slideResearch highlights▶ Effect of the sulfiding pretreatment (H2/H2S and N2/H2S mixture) on Re/ZrO2 and Re/ZrO2-sulfated catalysts for the hydrodeoxygenation of guayacol were investigated. ▶ It was found that Re/ZrO2 and Re/ZrO2-S catalysts sulfided under N2/H2S mixture increases the activity of guayacol hydrodeoxygenation. ▶ The increase in the H2S partial pressure decreases the activity of guayacol hydrodeoxygenation and changes the (phenol/cathecol) ratio, favoring the formation of cathecol.