加氢法制苯甲醛的MnO_x/Al_2O_3催化剂研究  

Study on MnO_x/Al_2O_3 Catalysts for Producing Benzaldehyde with Hydrogenation Technology

作　　者：潘云飞[1] 林陵[1] 曾崇余[1] 

机构地区：[1]南京工业大学化学化工学院,江苏南京210009

出　　处：《化工时刊》2007年第6期18-21,共4页Chemical Industry Times

摘　　要：采用等体积浸渍法制备了MnOx／Al2O3催化剂，在固定床连续反应器上考察了MnOx负载量对苯甲酸加氢制备苯甲醛的催化性能的影响，采用TG-DSC、H2-TPR、NH3-TPD和CO2-TPD等手段对催化剂进行了表征，并与催化剂活性和苯甲醛选择性关联。研究表明，在常压、380℃、氢气空速为760h^-1、氢／酸物质的量比为68的条件下，锰负载量为10％-15％的催化剂苯甲酸转化率在92％以上，苯甲醛选择性接近90％。H2-TPR表明，苯甲酸加氢反应与催化剂的氧化还原性有很大的关联，催化剂表面氧空位增加对苯甲酸加氢反应有利。NH3-TPD和CO2-TPD表明催化剂的表面酸碱性对反应活性有很大影响，具有表面弱酸性和中等强度碱性的催化剂活性和苯甲醛选择性比较高。A series of MnOx/Al2O3 catalysts were prepared with hole volume saturation impregnation. The catalytic performance of MnOx/Al2O3 catalyst for vapour- phase hydrogenation of benzoic acid to benzaldehyde was investigated in a continuous flow and fixed - bed reactor. TG - DSC, H2 - TPR, NH3 - TPD and CO2 - TPD were employed to characterize catalyst. The results showed that under the reaction conditions of atmospheric pressure, 380℃, hydrogen space velocity 760 h^-1, and n（hydrogen）/n（benzoic acid） = 68, the conversion of benzoic acid and selectivity of benzaldehyde reached 92 % and 90 %. H2 - TPR results showed that the reaction activity was associated with the redox properties of catalysts, a increasing number of oxygen vacancy sites on the surface of catalysts were beneficial to the reaction. NH3 - TPD and CO2 - TPD results showed that when the surface of catalysts had the weak acid sites and middle basic sites, the reaction activity and selectivity of benzaldehyde were higher.

关 键 词：MnOx/Al2O3 加氢 苯甲酸 苯甲醛 表征 

分 类 号：O643.32[理学—物理化学]