Catalytic Hydrogenation Of Microcrystalline Cellulose To Eg Over Ni Amorphous Alloy Catalyst

In this paper, a series of NiWB and NiWB/CNTs catalysts were prepared by using chemical reduction method, sodium borohydride(abbreviate NaBH4, the same below) as reducing agent to reduce nickel acetate(C4H6NiO4·4H2O) and ammonium paratungstate((NH4)6H2W12O40) and CNTs as carrier. The catalytic performance of the catalytic conversion of cellulose into ethylene glycol(abbreviate EG) was explored. The effect of NaBH4 concentration and CNTs on the performance of the catalyst was studied. The optimum NaBH4 concentration was determined. The effects of reaction temperature,reaction time, hydrogen pressure and catalyst dosage on the conversion of cellulose and the selectivity of EG were studied by experiments, the catalysts were characterized by BET、TEM、XPS、NH3-TPD、XRD、ICP etc.The experimental results show that the appropriate concentration of reducing agent is0.5mol/L; The optimum reaction conditions are: reaction temperature 250℃, reaction time2 h, reaction hydrogen pressure 6MPa, cellulose and catalyst dosage is 0.5g/0.15 g. Under the conditions of modification, the conversion of microcrystalline cellulose was 100%, the yield of EG is 53%, hexahydric alcohol(sorbitol and mannitol, the same below) was13.67%, 1,2- PD yield was 7.01%. The XRD results show that the fresh catalysts showed an amorphous structure. The results of BET indicates that the concentration of reducing agent will impact the structure of the catalysts remarkably. The results of XPS shows that surface element composition of catalyst was changed by the concentration of reducing agent. TEM results showed that the catalyst had better dispersion under low reducing agent concentration.The experimental results of Ni WB/CNTs show that the optimum reaction conditions are: reaction temperature 250℃, reaction time 2h, reaction hydrogen pressure 6MPa,cellulose and catalyst dosage is 0.5g/0.15 g. Under the conditions of modification, the conversion of microcrystalline cellulose was 100%, the yield of EG is 57.7%, hexahydric alcohol was 10.3%, 1,2- PD yield was 4.6%. The results of NH3-TPD and XPS show that the acid synergistic effect of CNTs and WO3 increased the acidity of the catalyst. The results of XPS show that the metallic nickel has catalytic activity.