CuO/SBA-15催化剂上巴豆醛选择性加氢

Crotonaldehyde Hydrogenation over CuO/SBA-15 Catalyst

通过γ-氨丙基三甲氧基硅烷(APTS)偶联与Cu2+离子络合两步法将CuO负载到介孔分子筛SBA-15上,制得CuO/SBA-15催化剂,考察了催化剂的巴豆醛选择性加氢反应性能.通过X射线粉末衍射、氮气吸脱附和程序升温还原(TPR)技术对催化剂进行了表征.结果表明,SBA-15分子筛负载CuO后保持原有的介孔结构,但是孔容和比面表积随着CuO负载量的增大而下降.TPR结果表明CuO/SBA-15系列催化剂有三种CuO物种:高分散CuO、晶相CuO和进入SBA-15分子筛骨架的Cu2+.高分散CuO物种对巴豆醛加氢反应的催化活性最高,晶相CuO物种次之,而进入SBA-15分子筛骨架的Cu2+物种几乎没有活性.

CuO catalysts supported on SBA-15 were prepared by chelating Cu^2＋ with γ-aminopropyltrimethoxysilane （APTS） on the SBA-15 support and were tested for selective hydrogenation of crotonaldehyde. The CuO/SBA-15 catalysts with different CuO loadings were characterized by X-ray diffraction, N2 sorption, and hydrogen temperature-programmed reduction （H2-TPR）. N2 sorption results showed that the samples maintained a fine 2D-hexagonal structure after the CuO was loaded, whereas the BET surface area and pore volume decreased with increasing Cu content. He-TPR results revealed that there were three Cu species： finely dispersed CuO, bulk CuO, and Cu^2＋ ions incorporated into the framework of SBA-15. Catalytic activity of each species was evaluated. The finely dispersed CuO had the highest activity, and the bulk CuO had medium activity, while the Cu^2＋ in the SBA-15 framework was inactive in the reaction. These indicated that the finely dispersed Cu species were the active phase for the reaction. Furthermore, the catalyst calcined under N2 instead of air could increase the content of the finely dispersed CuO, which could consequently enhance the catalytic activity.