Abstract:

WO _x /SBA?15 catalysts with different loading amounts were prepared by wet impregnation method, and the effect of WO _x dispersion on the olefin disproportionation reaction was discussed.The results show that the loading amount affects the dispersion of WO _x on the carrier surface, as well as the catalytic activity.The best catalytic performance of WO _x /SBA?15 can be achieved with 10% loading amount of WO _x .The higher loading amount of WO _x could induce aggregation of WO _x on the SBA?15 surface, and then covering the active sites.The weaving properties of the samples were characterized by physical adsorption,XRD,SEM,and the acidity and acid amount of the samples were characterized by pyridine IR and chemisorption. Reaction evaluation shows that the sample with 10% loading amount of WO _x exhibits the best catalytic activity.The propylene yield of the 10% WO _x /SBA?15 catalyst is up to 50% and the propylene selectivity is nearly 90%.

Key words: Impregnation method, Olefin disproportionation, Dispersion, Catalytic activity

摘要：

采用湿浸渍法制备了不同负载量的WO _x /SBA?15催化剂，讨论了WO _x 分散性对烯烃歧化反应的影响。结果表明，负载量影响了WO _x 在载体表面的分散度，进而影响催化活性；负载量10%的催化性能最佳；高负载量的WO _x /SBA?15表面聚集态WO _x 数目较多，掩盖了活性位点。采用物理吸附、XRD、SEM表征样品织构性质，采用吡啶红外、化学吸附表征了样品的酸性和酸量。反应评价显示10%负载量的10%WO _x /SBA?15催化活性最佳，丙烯收率可达50%，丙烯选择性近90%。

关键词: 浸渍法, 分散度, 烯烃歧化, 催化活性