乙醇制1,3-丁二烯MgO/SBA-15催化剂的制备及其催化性能

以介孔分子筛SBA-15为载体,采用浸渍法制备了新型负载型MgO/SBA-15催化剂,采用低温N₂吸附-脱附、X射线衍射(XRD)、透射电子显微镜(TEM)、²⁹Si核磁共振(²⁹Si NMR)、NH₃程序升温脱附(NH₃-TPD)、CO₂程序升温脱附(CO₂-TPD)等表征手段研究了不同MgO负载量(质量分数)对催化剂的结构、物化性能和催化乙醇合成丁二烯反应活性的影响。 研究结果表明,MgO负载量为20%时,所制备的催化剂的活性最好,此时MgO高度分散在载体SBA-15的有序孔道中,形成了Mg-O-Si结构,有利于提高目标产物丁二烯的选择性。 该催化剂在温度350 ℃、进料质量空速2.64 h^-1的反应条件下,可获得最佳催化效果,乙醇转化率最高可达55.8%,丁二烯选择性可达80.2%。 MgO/SBA-15催化剂在乙醇法生产丁二烯工艺中具有潜在的应用前景。

Preparation of MgO/SBA-15 Catalyst and Its Catalytic Performance for the Synthesis of 1,3-Butadiene from Ethanol

The novel MgO/SBA-15 catalysts were prepared via impregnation of magnesium oxide onto the SBA-15 zeolite support. The effect of MgO content on the structure, physic-chemical properties and catalytic performances of catalysts was studied by Brunauer-Emmett-Teller(BET) measurement, X-ray diffraction(XRD), transmission electron microscopy(TEM), ²⁹Si NMR(nuclear magnetic resonance) spectroscopy, NH₃-TPD(temperature programmed desorption) and CO₂-TPD. It is found that the catalyst with 20% mass fraction of MgO can form well-dispersed MgO in the inner pores of SBA-15 zeolite and the Mg-O-Si structure between MgO and SBA-15, which is beneficial to the production of 1,3-butadiene. Under the optimal reaction conditions of 350 ℃ and feed weight hourly space velocity of 2.64 h^-1, the best catalytic performance is obtained with the ethanol conversion of 55.8% and the 1,3-butadiene selectivity of 80.2%. The MgO/SBA-15 catalyst has potential applications in the production of butadiene from ethanol.