|
Lower alcohols, including methanol, ethanol, propanol, isopropanol, ethylene glycol, propylene glycol and glycerin, are important chemical raw materials and chemical intermediates in chemical production widely used in the automotive, industrial, chemical, food, medicine and cosmetics industries. Since these alcohols were produced mainly by the raw materials from petroleum resource, the exhaustion of oil resource and the environmental pollution problems followed. The process of biomass renewable resource to lower alcohols shows broad prospects due to economic advantages, meeting the requirements of sustainable development.In this paper, the Ni, Mo, Cu/kieselguhr catalysts were prepared and used for sucrose hydrogenolysis. Kieselguhr is the support when the nitrates of Ni, Mo and Cu are the precursors. The process of catalyst preparation are discussed and optimized. Furthermore, the catalysts are characterized using the technique of X-ray diffraction, surface area measurement and temperature program reduction. The effects of calcinations conditions, baking time, addition sequence and the composition of the active components on activity of catalysts were studied. In addition, the effects of reaction temperature and pressure were studied in this research as well.With the temperature and pressure increasing, the hydrogenolysis rate of sugar also increased rapidly at start time. The yield of target products was enhanced to the highest at 150℃. When the temperature was above 180℃,the severe hydrogenolysis of sugar could decrease the yield of desired products due to the fierce side reaction. Beside, we get the most low alcohols under 6MPa H2 pressure when the amplification with the pressure increasing is not obvious under this H2 pressure.Ni is very common in most of the catalysts used for hydrogenation process. The presence of Mo and Cu promotes the activity of Ni supported on kieselguhr. It was found that the yield of lower alcohols increased with the increase of components of Ni. While the content of Ni arrive a certain value, the growing rate is not obvious. the same trend was found for Cu and Mo. The optimum (Ni,Mo,and Cu)/kieselgur catalyst has the following composition:Ni,30.04% by weight of catalyst;Mo,7.21% by weight of catalyst;Cu,1.28% by weight of catalyst with the corresponding conversion of sucrose and yield of lower alcohols were 93.63% and 21.1%, respectively.
|