Continuous one-pot hydrodeoxygenation of sorbitol to fuel components over Pd/WO –ZrO2 catalysts

Abstract

The one-pot hydrodeoxygenation (HDO) of an aqueous sorbitol solution (20 wt%) was studied over Pd (0.5 wt%)/WOx–ZrO2 catalyst at the variable reaction conditions in a continuous mode focusing on the effect of the calcination temperature of tungstated zirconia (1073 and 1223 К), the Pd containing catalyst reduction temperature, as well as on the correlation between their physical-chemical properties and fuel hydrocarbons yield. It was found that sorbitol HDO under reaction conditions such as temperatures 573 and 613 K, hydrogen pressure 4.0 MPa, and WHSV of 1.0 h–1 resulted in the highest yield of C5+ hydrocarbons 76–81 mol% mainly consisting of isoalkanes, cycloalkanes, n–alkanes and arenes. The maximum yield of the targeted isoalkanes and cycloalkanes with RON>70 (34 mol%) along with the minimum amount of undesirable C6–C8 arenes (2 mol%) were obtained at 613 K. Under these conditions the Pd catalyst reduced at 613 K using tungstated zirconia calcined at 1073 K as a support afforded formation of Pd/WOx–ZrO2 with the optimal microtexture, acidity and dispersion of catalytically active phase. Physicochemical properties of the catalyst and support were studied by XRD, low temperature N2 physical adsorption, NH3–TPD, H2–TPR, CO chemisorption, XPS, and CO2–TPD.