Porous Materials Based Catalysts For The Selective Oxidation Of Hydrocarbon

As key intermediates of fine chemicals,epoxides and aromatic ketones can be produced by the selective oxidation of hydrocarbons.Hence,developing efficient catalysts for such reaction is of highly importance.Compared with conventional homogeneous catalysts based on transition metal complex,heterogeneous catalysts are preferable due to their convenient separation from reaction mixture and recycle.In this work,efforts were made to develop heterogeneous catalysts for the selective oxidation of hydrocarbons.Loading catalytic active components onto proper supporters is a valid route to produce heterogeneous catalysts.In general,the surface area and porosity of materials have conspicuous impact on their catalytic performance.Metal-organic frameworks(MOFs)are regarded as promising supporters owing to their large surface area,tunable pore structure and facile modification.Herein,heterogeneous catalysts with cobalt imine-pyridine-carbonyl complex sites were developed using NH₂-MIL-101 as supporter.The MOF-based catalysts showed high activity on the aerobic epoxidation of alkene.The catalytic performance decreased gradually during the first runs but remained almost unchanged in the following cycles,which is probably due to the transformation of cobalt coordination surroundings.Research on carbon-based metal-free catalysts was further performed for developing a more sustainable system and avoiding the metal pollution from the origin.Sulfur,nitrogen dual doped porous carbon materials were prepared by pyrolyzing the mixture of polymer precursor and templates,that is,nano-Ca CO₃ or nano-Si O₂.The surface area and porous structure of resultant materials are enhanced with the employment of templates.Besides,it is noteworthy that nano-Ca CO₃ promotes the sulfur content to a large degree,and has a significant influence on the mode of sulfur.The carbon-based catalysts exhibited satisfactory catalytic performance on the selective benzylic C-H oxidation of aromatic alkane.Furthermore,their catalytic effects are highly related to the content and mode of hetero elements.