WO_3-SiO_2模型催化剂孔径对C_2H_4-C_(10)H_(20)歧化性能的影响

蒸发自组装30~150 nm单分散SiO2微球制备孔径均一的SiO2模型载体,采用等体积浸渍法制备WO3单层负载WO3-SiO2催化剂并对其进行低温氮吸附、压汞、程序升温氨脱附和扫描电子显微镜等表征,然后进行C2H4-C10H20歧化反应实验。结果表明,在相同的实验条件下,相同孔道结构的球形SiO2模型载体孔径对反应结果有重要的影响。催化剂孔径越大,起始乙烯转化率和丙烯选择性越高,反应失活也越快,即内扩散对C2H4-C10H20歧化反应有明显的影响。

Influence of WO3-SiO2 Model Catalysts Pore Diameter on C2H4-C10H20 Metathesis

The spherical model support with uniform pore diameter were fabricated by ordered packing of 30~150 nm monodisperse SiO2 microspheres.WO3-SiO2 metathesis catalysts of WO3 loading amount of monolayer were prepared through impregnation and characterized by means N2 adsorption-desorption,mercury penetration,NH3 temperature programmed desorption and SEM.The catalytic properties of WO3-SiO2 catalysts were evaluated in C2H4-C10H20 metathesis reaction under the same reaction conditions.The results showed that the catalytic properties of WO3-SiO2 model catalysts were dependent on the spherical model supports pore diameter with the same pore structure.The bigger pore size of the catalyst,the higher ethene conversion and propene selectivity in the initial stage of C2H4-C10H20 metathesis reaction.However,the deactivation rate of the catalyst was also higher,the internal diffusion had a strong influence on C2H4-C10H20 metathesis reaction.