Hydrodeoxygenation of sorbitol to gasoline-range hydrocarbons over Pt, Pd, Rh, Ru, Ni catalysts supported on tungstated alumina

Catalytic properties of the tungstated alumina (WA) supported catalysts with different nature and content of active metal (Pt, Pd, Rh, Ru, Ni) were studied in the continuous flow hydrodeoxygenation of sorbitol at a temperature of 653 K, a pressure of 4.0 MPa, and weight hourly space velocity (WHSV) of 1.0 h(-1). The catalysts were characterized by N-2 physical adsorption, H-2-TPR, CO chemisorption, TEM, and NH3-TPD. It was found that all catalysts provide complete conversion of sorbitol with the formation of C-5-C-7 hydrocarbons as the main products which include n-alkanes, cycloalkanes, and isoalkanes. The yield of C-5-C-7 hydrocarbons after 1 h of the reaction increases from 42 to about 74 mol% in a series of catalysts: 5% Ni/WA < 0.5% Ru/WA < 0.5% Pd/WA < 0.5% Rh/WA < 0.5% Pt/WA. The calculated value of the research octane number (RON) for the C-5-C-7 mixture rises from ca. 62 to 80 in a series of catalysts: 0.5% Pt/WA < 0.5% Pd/WA < 0.5% Rh/WA < 5% Ni/WA < 0.5% Ru/WA. The stable yield and RON values (no less than 57 mol% and 70, respectively) of C-5-C-7 hydrocarbon mixture are achieved during hydrodeoxygenation over the 0.5% Pd/WA catalyst for 8 h.