Sba-15 Mesoporous Materials, Function And Its Applications

Recently, a significant number of homogeneous catalysts have met some difficulties in terms of separating and recycling in the reaction system, especially some homogeneous catalysts which are matched with the precious metals and organic ligand will lead to serious environmental pollution and bring waste, higher costs and resource problems. To solve these problems, scientific workers have made a great number of researches from every aspect. Among of them, the best way is to choose a appropriate supporter which can be matched with different functional group. The mesoporous SiO2 nano materials SBA-15, as a new type of inorganic supported materials, has been widely used in organic functional modification and the catalysts loaded by metal.SBA-15 has a series of advantages, such as ordered pore structural, large specific surface area, uniform pore diameter and so on. In addition, the supported catalysts can be easily separated by centrifugation and filter. And the modified SBA-15 still has a uniform pore size. SBA-15, which is prepared by co-condensation, can make the loaded functional group disperse in the surface of the pore. Space limited effect in the pore will improve the catalysis environment and enhance the catalysis effect. Therefore, we have made two type of mesoporous silica-supported catalysts which prepared by different methods. And we also have carried out a amount of exploration of their catalysis performance.In the first part, we develop a facile preparation of mesoporous silica-supported iridium catalyst and apply it to C-3 alkylation of oxindole with various alcohols. The feature of it is that a mesoporous indene-modified SBA-15, a functionalized material, was prepared by co-condensation method. The multi-function of indene group is to match various transit metals which may result in an extensively application in catalytic reaction. The results showed that the catalyst exhibited high catalytic activity in C-3 alkylation of oxindole with various alcohols. What's more, such type of heterogeneous catalyst could be recovered and reused eight times without affecting its reactivity obviously, showing a good potential in industrial application.In the second part, a kind of mesoporous SBA-15 materials containing chiral (S,S)-TsDPEN were prepared through evaporation induced self-assembly(EISA) method. And the materials were complexed with [Cp*RhCl2]2. Then the chiral N-sulfonylated diamine-basedη5-Cp*-Rh heterogeneous catalyst with a 2D hexagonal structure was gotten. The catalysts exhibited high catalytic activity and high asymmetric stereoselectivity in the asymmetric hydrogen transfer of aromatic ketones. Furthermore, such a catalyst could be recovered easily and used repetitively five times without significantly affecting its catalytic activity and asymmetric stereoselectivity.