超细镍基催化剂对环戊二烯的选择性催化加氢性能

ULTRAFINE NICKEL CATALYSTS CATALYZED SELECTIVE HYDROGENATION OF CYCLOPENTADIENE

用原位溶胶-凝胶法制备了不同SiO_2含量及不同n(Ni):n(Mo)的负载型高性能超细镍金属NiO-MoO_3 /SiO_2-Al_2O_3-TiO_2催化剂。并以双环戊二烯为原料,经过热解聚得到环戊二烯,用脉冲反应色谱法研究了环戊二烯的选择性加氢生成环戊烯的过程。使用配方为S_2的催化剂,在反应温度50℃,载气流速30 mL/min,双环戊二烯进样量10μL时,环戊烯的选择性达到100%。由程序升温还原及正丁胺程序升温脱附法分析表明,催化剂的表面产生了还原性能不同的多种镍原子活性位,金属镍与载体间的相互作用增强,为中等强度的酸性催化剂。脉冲反应过程动力学的研究表明,该反应机理符合Rideal-Eley模型,并用该模型估算了环戊二烯加氢生成环戊烯的表观活化能,其结果为82.8 kJ/mol。

The NiO-MoO3/SiO2-Al2O3-TIO2 ultrafine nickel catalysts with different SiO2 contents and molar ratios of Ni/Mo were prepared by an in situ sol-gel method. The catalyst performance in the selective hydrogenation of cyclopentadiene was carried out in a pulse microreactor, combined with a GC. The selectivity to cyclopentene in the hydrogenation of cyclopentadiene over S2 catalyst was 100% under the conditions：reaction temperature 50℃ ,flow rate of carrier gas 30 mL/min and injection of 10 μL dicyclopentadiene. The results showed that the catalysts have excellent selectivity toward cyclopentene, and the catalytic performance is better than one of the compared industrial catalyst. The catalysts were characterized by temperature-programmed reduction （TPR）, butylamine-temperature-programmed desorption （C4 H9 NH2-TPD）. The results showed that the catalysts have several kinds of active sites of nickel components and the interaction between Ni and the support is enhanced. This type of catalysts has middle acid strength. The integral kinetics of the reaction was also investigated, and the results showed that the reaction mechanism is in accord with the Rideal-Eley model, from which the apparent activation energy for the hydrogenation of cyclopentene to cyclopentadiene was estimated to be 82.8 kJ/mol.