Ti-Si复合氧化物催化剂的合成、表征及邻苯二酚O-单醚化反应性能

采用溶胶-凝胶法制备了不同Ti/Si比的钛硅氧化物及纯SiO₂和TiO₂样品， 通过XRD, FT-IR, UV-vis, NH₃-TPD和氮吸附等手段对材料的物理化学性质进行了表征. 结果表明， Ti-Si复合氧化物以无定形状态存在， 随着硅量的增加， 钛的存在形态由六配位为主向四配位为主转变， 表面酸量降低； 样品在以邻苯二酚和甲醇为原料气相法合成愈创木酚反应中的活性结果表明， n(Ti) ∶n(Si)＝6 ∶1的样品活性最高68％， 随着Ti/Si的减小活性降低， 这可能与样品表面酸量和酸类型变化有关.

Preparation and Characterization of Ti-Si Mixed Oxides and Their Catalytic Activities for Vapour-phase O-Methylation of Catechol

Ti-Si mixed oxides catalysts with different Ti/Si ratios were prepared by sol-gel method and characterized by means of XRD, FT-IR, N₂ adsorption, UV-vis and NH₃-TPD. The results show that the morphologies of Ti-Si mixed oxides change from anatase structure to amorphous with the addition of silicon. Both the acidic amount and strenth on the catalysts surface decrease with increasing Si content. Vapor-phase O-methylation of catechol with methanol was investigated over various Ti-Si catalysts. The results show that the sample of n(Ti) ∶n(Si)=6 ∶1 exhibits the highest activity (68%) and the activity decreases with increasing Si contents, which might relate to the amount and species of the surface acid.