水热体系下ZrO_2-SiO_2混合氧化物催化纤维素转化

Catalytic Conversion of Cellulose in the Presence of Mixed-Oxide ZrO_2-SiO_2 Under Hot Compressed Water( HCW) Condition

采用共沉淀法合成了混合氧化物Zr O2-Si O2。用XRD,BET,NH3-TPD对其结构性质进行了表征。在水热条件下利用该催化剂催化纤维素转化。考察了n(Zr)/n(Si)、反应时间、反应温度等因素对纤维素转化的影响。结果表明,Zr O2-Si O2混合氧化物具有较高的酸量,n(Zr)/n(Si)=7时催化剂酸量最高,催化效果最优。反应条件为200℃、2.5 MPa N2、5 min时,纤维素转化率达到59.0%,葡萄糖、乳酸、乙酰丙酸、5-HMF的总收率为26.9%。

Mixed-Oxide ZrO2-SiO2 was prepared by co-precipitation method and characterized by XRD, BET and NH3-TPD. The conversion of cellulose catalyzed by ZrO2-SiO2 was studied under hot com- pressed water （HCW） condition. The influences of Zr/Si molar ratio, reaction time and temperature on cellulose conversion were investigated. Results showed that ZrO2-SiO2 possessed more acid sites. ZrO2- SiO2 with a Zr/Si molar ratio of 7：1 presented the highest acidity and reactivity toward hydrolysis and dehydration reactions. The conversion of cellulose reached 59.0% and the total yield of glucose, lactic acid, levulinic acid and 5-HMF were 26.9% within 5 min at 200 ℃ , 2.5 MPa N2.