MOR@SAPO-11复合分子筛的合成及Pt/MOR@SAPO-11催化剂的加氢异构化性能

采用硅铝源法制备具有核壳结构的复合分子筛MOR@SAPO-11。利用XRD、SEM、N2物理吸附 脱附曲线、NH3-TPD和Py-FTIR等手段对MOR@SAPO-11复合分子筛的晶体结构、分子筛形貌和酸性质进行表征。结果表明，采用硅铝源法制备的复合分子筛MOR@SAPO-11呈现以丝光沸石为核，SAPO-11为壳的核壳结构。相比于单一分子筛MOR、SAPO-11和机械混合物MOR+ SAPO-11，MOR@SAPO-11复合分子筛具有更适宜的酸性和较高的B酸分布。这说明MOR@SAPO-11复合分子筛发生了协同作用，通过物理或者化学作用紧密相连，改善了自身的酸性。在相同的反应条件下，以硅铝源法制备的复合分子筛MOR@ SAPO-11为载体的Pt催化剂异构化活性和异构烃选择性比以单一分子筛和机械混合分子筛为载体的Pt催化剂有明显提高。

Synthesis of MOR@SAPO-11 Composite Molecular Sieve and the Hydroisomerization Evaluation of Pt/MOR@SAPO-11 Catalyst

The core-shell structure MOR@SAPO-11 composite molecular sieve was synthesized by using silica-alumina source method. The framework structure，crystals patterns and acid property of MOR@SAPO-11 molecular sieve were characterized by using XRD, SEM, N2 adsorption/desorption isotherm, NH3-TPD and Py-FTIR. Results show that the composite zeolites exhibit uniform structures morphology. MOR and SAPO-11 zeolites act as core and shell, respectively. Compared with MOR, SAPO-11 and MOR+ SAPO-11, MOR@ SAPO-11composite molecular sieve has more suitable acid and higher Br?nsted acid strength. The promotion effect is attributed to complex pore channel structure and acid sites of MOR@ SAPO-11 molecular sieve, with improved cooperation between MOR and SAPO-11 in the composite molecular sieve. Results demonstrate that the conversion and isomer selectivity of n-C12 over Pt loaded MOR@ SAPO-11 were obviously enhanced, much higher than the Pt-based catalysts supported by MOR, SAPO-11 and MOR+SAPO-11, respectively.