Preparation And Catalytic Performance Of Mesoporous Metal(Salen) Composite

Heterogeneous catalytic oxidation is one of the more important research fields in the catalytic chemistry. Metal-salen complexes have already been reported important catalytic oxidation catalysts towards to all kinds of reactions, which exhibit excellent catalytic performance. However, the homogeneous catalysts often suffer from difficulty in the separation and recovery at the end of process, resulting in catalyst waste and the environment pollution. Therfore, in consideration of economic and environmental point of view, the heterogenization of Metal(salen) complexes and the design of hetegeneous catalysts in order to improve the catalytic performance are effective way to achieve their application. Accordingly, we have done following works.1. We prepared mesoporous structured aminopropyl group-functionalized SBA-15 silica materials supported Mn(salen) composite catalyst in the presence of NaClO solution by grafting method using tetraethyl orthosilicate (TEOS) as a inorganic silica source and 3-aminopropyl-trimethoxysilane(APS) as a linker reagent.The structure, and porosity of the resulting composite catalyst was well-characterized by Fourier transform infrared (FT-IR) spectroscopy, UV-vis diffuse reflectance spectroscopy (UV-vis/DRS), low-angle X-ray diffraction (LXRD) analysis, inductively coupled plasma atomic emission spectroscopy (ICP-AES), and transmission electron microscopy (TEM); Subsequently, the oxidation catalytic activity and selectivity of homogeneous and heterogeneous catalysts were studied through the epoxidation of styrene by using aqueous NaCIO as the oxidant and PPNO as axial catalyst; meanwhile, The influences of key reaction parameters, including the Mn(salen) loadings, axial ligand, molar ratios of NaCIO to styrene, and reaction time were also studied. Finally, the reusability of the catalysts was evaluated.2. We prepared mesoporous structured aminopropyl group-functionalized PMO silica materials supported Mn(salen) composite catalyst in the presence of NaCIO solution by grafting method using 1,2-bis(triethoxysilyl)ethane (BTSE) as a organic silica source and 3-aminopropyl-trimethoxysilane (APS) as a linker reagent. The structure, and porosity of the resulting composite catalyst was well-characterized by Fourier transform infrared (FT-IR) spectroscopy, UV-vis diffuse reflectance spectroscopy (UV-vis/DRS), low-angle X-ray diffraction (LXRD) analysis, inductively coupled plasma atomic emission spectroscopy (ICP-AES), nitrogen sorption analysis, and transmission electron microscopy (TEM); Subsequently, the oxidation catalytic activity and selectivity of homogeneous and heterogeneous catalysts were studied through the epoxidation of styrene by using aqueous NaClO as the oxidant and PPNO as axial catalyst; meanwhile, The influences of key reaction parameters, including the Mn(salen) loadings, axial ligand, molar ratios of NaClO to styrene, and reaction time were also studied. Finally, the reusability of the catalysts was evaluated.