掺杂元素对TiO2/SO2-4固体酸特性的影响

为了进行掺杂元素对超强酸特性的影响研究,采用均匀沉淀法合成了Fe、Si、Al和Zr氧化物掺杂的TiO2/SO2-4的固体酸(TiO2-MrOy),采用XRD、FTIR、NH3-TPD以及H2-FPR等分析方法对催化剂进行表征.以大豆油和甲醇的酯交换反应为活性评价反应,比较了各催化剂的催化活性.研究发现,除了Al外掺杂元...

Properties of solid acid TiO2/SO42 - doping different oxides

 Mixed oxides TiO₂-M_xO_y(M=Fe, Si, Al, Zr）prepared by co-precipitation method were impregnated in aqueous solutions of sulfuric acid to form doped solid acid samples.These catalysts were characterized by XRD, FTIR, NH₃-TPD and H₂-TPR.Their catalytic activity was tested in the transesterification reaction between soybean and methanol.The results showed that the addition of second oxide into TiO₂/SO₄^{2 -} could improve the catalytic activity and inhibit the formation of TiOSO₄ in impregnation process except Al.The restraint effect was the strongest for silica.The doping of Si, Zr and Fe oxides could enhance surface acidity of catalysts while the addition of Al even made the acidity lower.The decrease of reduction temperature by H₂ was larger for Fe-involving sample than for Si-involving one.The Fe doped catalyst was found to be readily reusable in activity upon reuse for three times with subtle decrease conversion.