大孔SO_4^(2-)/ZrO_2-SiO_2复合固体酸制备及催化性能  

Macroporous SO_4^(2-)/ZrO_2-SiO_2 Solid Superacid Catalyst:Preparation and Catalytic Property

作　　者：侯琳熙[1] 尹锡俊[1] 龙能兵[1] 杨沈激[1] 张瑞丰[1] 

机构地区：[1]宁波大学材料科学与化学工程学院,宁波315211

出　　处：《无机化学学报》2012年第2期239-244,共6页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.20674041);宁波大学王宽诚幸福基金资助项目

摘　　要：利用浸渍水解法在大孔SiO2载体上组装固体酸制备出大孔径SO42-/ZrO2-SiO2复合固体酸催化剂。用扫描电镜、红外光谱仪和粉末X射线衍射仪等对其进行表征,结果表明:大孔SiO2载体的毛细管效应促使ZrO2以纳米薄层方式均匀地沉积在SiO2薄层表面,并抑制了ZrO2晶体的生长和晶相的转变,载体的大孔全连通的结构赋予该复合材料高的通透性(孔径在1~2μm)、两面活性点和大的比表面积(约156 m2.g-1)。Hammett指示剂法测得经550℃焙烧后产物的酸强度H0值小于-13.75,属于固体超强酸。以乙酸正丁酯的合成为探针反应考察硫酸浸渍液浓度、焙烧温度等制备条件对其催化活性的影响,结果表明,该SO42-/ZrO2-SiO2固体酸具有较好的催化活性,当焙烧温度为550℃和硫酸浸渍液浓度为1.5 mol.L-1时,超强酸对酯化反应的催化酯化率达到97%。A macroporous SO42-/ZrO2-SiO2 solid superacid catalyst was prepared by using a macroporous SiO2 as a support and by introduction of ZrO2 via the dipping-hydrolysis method.The physicochemical properties of the composite materials were characterized by SEM,FTIR and XRD.The results show that the silica support have a strong capillary effect.This effect favors the formation of thin film ZrO2 cover on the 3D silica layer and delays the growth and phase transition of ZrO2.Furthermore,the silica support with connected macroporous pores provides the composite material with double active sites,higher permeability and larger specific surface area.The material calcined at 550 ℃ is estimated to have H0-13.75,indicating a solid superacid catalyst.The results of esterification for n-butanol with acetic acid under different conditions show that the SO42-/ZrO2-SiO2 catalyst exhibits a better activity of esterification,and the better yield of n-butyl acetate（97%） is obtained with the H2SO4 concentration of 1.5 mol·L-1 and the calcination temperature of 550 ℃.

关 键 词：固体酸 二氧化硅载体 二氧化锆 酯化反应 大孔材料 

分 类 号：O643.1[理学—物理化学]