MoO＿3／（TiO＿2－SiO＿2）催化剂的表面分散状态及催化性能的研究

用气相流动吸附法（ｇｒａｆｔｉｎｇ）制备复合载体，用浸渍法（ｉｍｐｒｅｇｎａｔｉｏｎ）制备ＭｏＯ３／（ＴｉＯ２－ＳｉＯ２）催化剂．应用ＬＲＳ和ＴＰＲ技术研究ＭｏＯ３在复合载体ＴｉＯ２－ＳｉＯ２表面的分散状态，发现ＴｉＯ２在ＳｉＯ２表面的分散可增强ＭｏＯ３与载体之间的相互作用，提高ＭｏＯ３在载体表面的分散阈值．催化剂的活性评价在固定床中压反应装置中进行，以６９％（ｗｔ）环己烷、２０％（ｗｔ）的环己烯、１０％（ｗｔ）的苯、１％（ｗｔ）的噻吩混合液为反应液，以噻吩、环己烯和苯的转化率作为催化剂的ＨＤＳ、ＨＹＤ、ＢＨＤ活性指标．结果表明，经ＴｉＯ２调变后，其ＨＤＳ、ＨＹＤ、ＢＨＤ活性都较原来高，对于不同ＭｏＯ３含量的ＭｏＯ３／（ＴｉＯ２－ＳｉＯ２），ＨＤＳ、ＨＹＤ催化性能测试发现，当ＭｏＯ３含量低于分散阈值时，其ＨＤＳ、ＨＹＤ活性随ＭｏＯ３含量线性上升，但在高于分散阈值后，几乎保持不变．该催化剂对苯几乎没有加氢活性，显示出很高的环己烯加氢选择性．通过分散阈值与其ＨＤＳ、ＨＹＤ活性的关系可知，分散阈值可作为优化加氢精制催化剂配比的一个重要参数，具有较强的实际意义

Studies on Dispersion State and Catalytic Activities of MoO 3/(TiO 2 SiO 2)

The surface dispersion state and reduction behavior of MoO 3/(TiO 2 SiO 2) were studied by LRS, TPR and their thiophene hydrodesulfurization (HDS), cyclohexene hydrogenation (HYD) and benzene hydrogenation (BHD) activities were measured in a fixed bed reactor with 0.5 g of catalyst at 2.8 MPa H 2 pressure. The results are as follows: (1) The incorporation of TiO 2 not only promoted the dispersion of MoO 3 on complex support but also enhanced the interaction between MoO 3 and complex support, therefore, the dispersion threshold of MoO 3 was raised. (2) The TPR results indicated that the reducibility of Mo 6+ on the complex carrier increased, while that on SiO 2 decreased at high temperature. (3) It is observed that catalytic activities linearly increased with MoO 3 content up to dispersion threshold and then remained almost constant independent of the MoO 3 content. (4) The measurement of the catalytic activities shows that the activities of MoO 3/(TiO 2 SiO 2) are higher than that of MoO 3/SiO 2. TiO 2 can greatly improve the HDS, HYD activity of MoO 3/SiO 2.