固体超强酸S_2O_8^(2-)/TiO_2-WO_3的制备及其催化性能研究

Preparation and Catalytic Activity of Solid Super-acid S_2O_8^(2-)/TiO_2-WO_3

用溶胶-凝胶法制备了固体超强酸S2O82-/TiO2-WO3,并对其进行了XRD与IR表征,用乙酸乙酯合成模型反应考察了其催化性能,系统研究了WO3的含量、焙烧温度等制备条件对S2O82-/TiO2-WO3性能的影响。实验表明:在(NH4)10W12O41.xH2O质量分数为5.0%、焙烧温度为500℃条件下通过溶胶-凝胶法制备的固体超强酸S2O82-/TiO2-WO3,其载体为微细且晶格不太完整的锐钛矿型TiO2,比表面积较大,具有比浸渍法制备的SO42-/TiO2更高的硫含量和更强酸性,并具有较高的催化酯化活性和稳定性,在反应条件为:醇酸摩尔比1.48∶1、催化剂用量为冰醋酸的6.0%、反应时间2.0h,乙酸转化率可达74.1%(不加分水器)。催化剂在无需任何再生的条件下重复使用,活性下降趋势平缓,显示良好的稳定性。

A novel solid super-acid S2O8^2-/TiO2-WO3 was prepared by solgel method and was characterized by XRD and IR. Its catalytic activity was investigated by acting as a catalyst to synthesize acetic ether. The preparation conditions have also been investigated ,that is, the mass ratio of （NH4）10W12O41 ·@xH2O used in the compound is 5.0 %, the calcination temperature is 500℃. The results show the carrier TiO2 of the catalyst is fine and its crystalline lattice incomplete, which results high specific surface area. The catalyst shows high catalytic activity and stability in the esterifieation with higher sulfur content and stronger acidity than SO42-/TiO2 by impregnation method. When the amount of catalyst is 6.0 % （based on mass of acetic acid）, molar ratio of absolute alcohol to glacial acetic acid isl.48：1, the conversion of acetic acid was 74.1% after 2.0 h. Meanwhile, the activity of catalyst used repeatedly declined slowly under no deactivation, which demonstrates that the solid super-acid S2O8^2-TiO2-WO3 has high stability property.