一步法制备多级孔全硅分子筛silicalite-1及其在丙烷脱氢中的应用

调节硅源、原料比例、加料顺序等结晶条件,采用一步水热法直接制备具有多级孔结构和高比表面积的全硅分子筛silicalite-1。SEM,BET及XRD表征表明其平均粒径250 nm,比表面积500 m~2·g~(-1),具有多级孔径结构,NH_3-TPD及红外测试表明其表面具有大量的弱酸位。将其作为催化剂载体,应用到丙烷脱氢制丙烯反应中,表现出优异的催化活性和稳定性。丙烷转化率超过40%,接近平衡转化率,丙烯选择性约95%,连续运行120 h催化性能基本保持稳定,相比传统丙烷脱氢Al2O3载体催化剂体系具有广阔的开发潜力和市场前景。

One-step synthesis of nano-silicalite-1 with hierarchical pore and application in dehydrogenation of propane to propylene

Haierarchical porous molecular sieve silicalite-1 was successfully prepared by one step hydrothermal method through adjusting agent resources, precursor components, charging order.Average size of the synthesized silicalite-1 was about 250 nm and surface area was up to 500 m²·g^-1.BET characterization showed the silicalite-1 was composed of hierarchical pore.Ammonia adsorption-desorption and FT-IR indicated that there were large amounts of surface weak acid sites.When silicalite-1 was applied as catalyst carrier in propane dehydrogenation to propylene,conversion of propane was up to 42%,closing to equilibrium conversion,and selectivity of propylene was around 95%.Notably,after continuous test of 120 h,activity and selectivity kept almost constant.Compared to commercial catalyst with alumina carrier,the prepared hierarchical porous silicalite-1 supported catalyst showed much better activity, selectivity and stability.