Abstract: Silica-supported H3PW12O40 (e.g. PW12/SiO2) catalysts were prepared in the sol-gel method to solve the problems of H3PW12O40 such as low surface area, difficult separation, and reuse. The catalysts were characterized by XRD and N2-adsorption, their catalytic performance for the condensation of benzaldehyde with glycerol evaluated. The effects of calcination temperature of catalyst, PW12 loading, catalyst dosage and reaction time were investigated. The results show that PW12/SiO2(550 ℃) solid acid have a mean grain size of 20.9~26.4 nm which are typically amorphous. The nanoparticles have high catalytic activity and stability for synthesizing benzaldehyde glycerol acetals. The optimum conditions are as follows: the catalyst calcination temperature is 550 ℃, PW12 loading (mass fraction ) is 10%, the catalyst dosage is 0.5 g, n(benzaldehyde)∶n(glycerol)=1∶1.1, the volume of toluene is 15 mL, the reaction time is 2.0 h. Under these conditions, the conversion of benzaldehyde is 99.2%. Obviouslyy, the unique structure of the Keggin anions and surface acid center and the high specific surface area and the pseudoliquid phase of PW12/SiO2 play an important role in the condensation of benzaldehyde with glycerol.

Key words: H3PW12O40 , Condensation , Sol-gel , Solid acid

摘要： 采用溶胶—凝胶法制备了不同w (磷钨酸)的H3PW12O40/SiO2(简称PW12/SiO2)固体酸催化剂,用
XRD和N2-吸附对PW12/SiO2固体酸催化剂进行了表征,考察了催化剂的焙烧温度、w (磷钨酸)、m (催化剂)、反应
时间的影响。结果表明,焙烧温度550℃,w (PW12)10%,m (催化剂)0.5g,n(苯甲醛)∶n(甘油)=1∶1.1、V(甲苯)
15mL,反应时间2.0h,苯甲醛的转化率达99.2%。PW12/SiO2固体酸催化剂所具有的独特Keggin阴离子结构和表
面酸中心、高表面积和准液相在苯甲醛和甘油的缩合中具有重要的作用。

关键词: 磷钨酸 , 缩合反应 , 溶胶-胶凝 , 固体酸