Catalytic Hydrogenation Of Cellulose To Produce Ethylene Glycol

The use of renewable biomass resources to produce high value-added chemicals has become a research hotspot in the field of energy catalysis.Two novel,high-efficiency,green catalysts were prepared and used in the catalytic reaction of high selectivity to ethylene glycol by direct catalytic hydrogenolysis of cellulose.The catalyst support ZrO2 was prepared by coprecipitation method.The alkali metal Cs modified Ni-H3PW12O40/ZrO2 series catalyst were prepared by two-step impregnation method and ion exchange method.These catalysts were characterized by several physic-chemical techniques such as XRD,XRF,BET,NH3-TPD,H2-TPR and FTIR.The catalytic performance of each catalyst was evaluated in the reaction of cellulose hydrogenation to ethylene glycol.The effects of reaction temperature,reaction time,Ni loading and W content on the catalytic activity were investigated.The results show that the optimal catalyst 5%Ni/Cs2.5H0.5PW12O40/ZrO2-2 obtained 100%cellulose conversion and 47.1%yield for ethylene glycol at 240℃,6 MPa H2 for 1 h.This catalyst exhibited poor reusability,and the ethylene glycol yield decreased to 22.2%after three recycled runs.A series of unsupported Ni-Mo-W trimetallic catalysts with different nickel contents were prepared.The prepared catalysts were characterized by BET,XRD,XPS and H2-TPR characterization methods.The influence of factors such as reaction temperature,reaction time,the content of Ni,the calcination temperature and the amount of the catalyst on the hydrogenation reaction of cellulose were discussed.The results show that the content of Ni doped in the catalyst has a great influence on the distribution and selectivity of the reaction products.The catalytic activity increases as the content of Ni in the catalyst increases.It was found that complete cellulose conversion(100%)was achieved over the optimal unsupported Ni-Mo-W trimetallic catalyst Ni2MolW1 along with a high ethylene glycol yield(61.75%)at 260℃,6 MPa H2 for 2 h.This catalyst has excellent reusability as the ethylene glycol yield was stabilized at 27%in the seven catalyst recovery cycle experiments.The characterization results show that Ni and W species(WOx)play a very good synergistic catalysis in the reaction of cellulose hydrogenolysis to ethylene glycol.