Direct conversion of cellulose into polyols over Ni/W/SiO2-Al2O3.

The direct conversion of cellulose into polyols over Ni/W/SiO(2)-Al(2)O(3) catalysts with different Al molar fractions was examined. For comparison, Cu/W/SiO(2)-Al(2)O(3), Fe/W/SiO(2)-Al(2)O(3), and Co/W/SiO(2)-Al(2)O(3) were also evaluated. The bulk crystalline structure was determined using X-ray diffraction (XRD). The surface acidity was probed via temperature-programmed desorption of ammonia (NH(3)-TPD). The textural properties were investigated using N(2) physisorption. The metal contents were confirmed via inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Among the various metal catalysts, Ni/W/SiO(2)-Al(2)O(3) was confirmed to be the most favorable for hydrogenolysis of cellulose into polyols. The effect of the Al molar fraction in SiO(2)-Al(2)O(3) on this reaction over Ni/W/SiO(2)-Al(2)O(3) was also investigated. It was found that the polyol yield was closely related to the total acidity of the support. Compared to Ni/W/SBA-15, Ni/W/SiO(2)-Al(2)O(3) (Al/(Al+Si)=0.6) showed better stability during the recycling test. The catalyst deactivation was confirmed to be caused by metal leaching.