Preparation and application of heterogeneous catalyst PCuMo₁₁/ nitrogen rich covalent organic framework material for olefin epoxidation with molecular oxygen oxidant

Epoxide is an important organic synthesis intermediate and chemical raw material that is mainly prepared from the olefin epoxidation. It is a very interesting work to prepare efficient catalysts with stability and recyclability for aerobic olefins epoxidation. Composite PCuMo₁₁/PC was prepared by using the nitrogen rich covalent organic framework material (PC) as support and the polyoxometalate PCuMo₁₁ as active substance. The materials were characterized by FT-IR, N₂ adsorption and desorption, XPS, TEM and EDS. The application of PCuMo₁₁/PC for heterogeneous catalytic epoxidation of olefins (styrene, 1-octene, cyclooctene, cyclododecene) with molecular oxygen oxidant has obtained high catalytic activity and selectivity. There is no significant decrease in catalytic activity after recycling over five times. The experimental results show that large surface area and rich nitrogen content in the skeleton of the two-dimensional layered nitrogen rich covalent organic framework material are benefit to disperse the catalytic active substance polyoxometalate uniformly and establish a relatively stable chemical link, so as to improve the catalytic activity and stability of the composite.