Study Of Catalytic Hydrogenation Of Cellulose

Cellulose is the most abundant and renewable biological resources in biosphere, effective use of cellulose can not only bring huge economic benefits, but also bring great social benefits. Because of the complex structure and stability of cellulose, the degradation of cellulose have many defects, so cellulose can not yet be used as a chemical resource. Developing a new method of green and high conversion of cellulose to make full use of resources is a major challenge. Ethylene glycol is an important chemical product, which is widely used in polyester, cosmetics and explosives, etc. Using cellulose preparation glycol has the vital significance.The catalytic activity of catalysts such as Pt/C,Pd/C,Ru/C and Rh/C are compared in the catalytic hydrogenation of hydroquinone. The results show that the activity and the selectivity are the best when Pt/C is selected as the catalyst. The catalysts with Pt as active component and activated carbon, SiO2, Al-MCM-41as supports are prepared. The results show that the activity and the selectivity are the best when Pt/C is selected as the catalyst in the catalytic hydrogenation of hydroquinone. The influences of reaction conditions such as temperature, hydrogen pressure, solvent and reaction time on the conversion of cellulose and the selectivity of ethylene glycol are studied when Pt/C is selected as the catalyst. The suitable conditions are as follows:the reaction temperature is 250℃, the hydrogen pressure is 4 MPa, solvent is water, the reaction time is 2 h.And then the hydrogenation of cellulose after the ultrasonic pretreatment is also studied. The influences of ultrasonic time and ultrasonic temperature on the conversion of cellulose and the selectivity of Ethylene glycol are examined, and ultrasonic pretreatment conditions is ultrasonic time for 20 min, ultrasonic temperature for 80℃. With Pt/C as catalyst in ultrasonic time 20 min, ultrasonic temperature for 80℃conditions, the influences of hydrogenation reaction conditions such as the reaction temperature, reaction time, and hydrogen pressure on the reactions conversion and selectivity of product influence are studied. Results show that cellulose conversion is improved greatly, and the selectivity of ethylene glycol objective product without apparent change after the ultrasonic pretreatment. The suitable ultrasonic pretreatment conditions are ultrasonic time for 20 min, ultrasonic temperature for 80℃.The suitable conditions are as follows:the reaction temperature is 250℃, the hydrogen pressure is 4 MPa, solvent is water, the reaction time is 2 h. The conversion of cellulose is 88.13% and the selectivity of ethylene glycol is 66.82% in this optimum condition.