溶胶-凝胶法制备Cu/SiO_2催化剂的表征与性能  

Characterizations and Catalytic Performances of Cu/SiO_2 Catalysts Prepared by Sol-Gel Method

作　　者：贺黎明[1,2] 陈晓春[1] 何海龙[2] 马京生[2] 王伟[2] 郝玉春[2] 

机构地区：[1]北京化工大学化学工程学院,北京100029 [2]中国石油化工股份有限公司北京化工研究院,北京100013

出　　处：《石油化工》2010年第12期1337-1343,共7页Petrochemical Technology

基　　金：中国石油化工股份有限公司资助项目(B05416)

摘　　要：以正硅酸乙酯为硅源,采用溶胶-凝胶法制备了草酸二乙酯(DEO)加氢催化剂Cu/SiO_2,考察了氨水的pH对催化剂比表面积、物相组成、活性组分分散性和铜元素价态等的影响;用BET,FTIR,XRD,XPS,TPR,SEM,TEM等技术对催化剂进行了表征。实验结果表明,pH较大时有利于催化剂中层状硅酸铜的形成,主要以无定形或微晶态形式存在;氨水pH为11.0的催化剂的比表面积可达458m^2/g,铜组分易从催化剂体相向表面迁移,层状硅酸铜在表面的分散性很好,易被还原成低价铜。对该催化剂在DEO加氢合成乙二醇反应中的催化性能进行了评价,在温度220℃、压力2.0 MPa、H_2的气态空速6250h^(-1)、DEO的液态空速0.55h^(-1)、n(H_2):n(DEO)=70的条件下,DEO的转化率可达96.0%,乙二醇的选择性为88.0%。A series of Cu/SiO2 catalysts for hydrogenation of diethyl oxalate （DEO） to ethylene glycol were prepared by the sol-gel method with tetraethoxysilane as the silicon source. Effects of the ammonia water pH value on specific surface areas, phase compositions, metal dispersions and copper valences of the catalysts were investigated. The catalysts were characterized by means of BET, FTIR, XRD, XPS, TPR, SEM and TEM. The results showed that high pH value was favorable to the formation of copper phyllosilicate, which existed mainly in amorphous or microcrystalline state. The specific surface area of the fresh catalyst reached 458 m^2/g at the ammonia water pH 11. The oxidized copper phyllosilicate could transfer easily from the catalyst bulk to its surface with high dispersion, which could be reduced easily to lower valent copper. The catalyst performance in the hydrogenation was evaluated. Under the reaction conditions of temperature 220℃, pressure 2.0 MPa, H2 GHSV 6 250 h^-1, DEO LHSV 0.55 h^-1 and n（ H2 ） ： n （DEO） 70, the conversion of DEO and the selectivity to ethylene glycol achieved 96.0% and 88.0%, respectively.

关 键 词：溶胶-凝胶法 铜/二氧化硅催化剂 层状硅酸铜 草酸二乙酯 加氢 乙二醇 

分 类 号：TQ203.2[化学工程—有机化工]