Synthesis Of Functional Microporous Organic Polymers Via Post-modified Strategy For Heterogeneous Catalysis

Porous organic polymers?POPs?are a kind of new porous materials.Compared with traditional porous materials such as zeolite,molecular sieve and porous silicon,POPs have low skeletal density,convenient chemical modifiability and could be equipped with hierarchical pores using reasonable molecular design.Therefore,in recent years,POPs have been widely studied and are used in the fields of separation,adsorption,biomedicine,and heterogeneous catalysis,etc.Although there are many researches on POPs,there are still broad space for development of various organic porous materials research.For example,how to prepare a kind of organic porous material having a controlled pore structure,and in the field of immobilized catalysis,how to easily load a catalytically active small molecule onto a porous material is still a challenging subject.This thesis was divided into three chapters.The first chapter is a general introduction of porous organic polymers and its applications and related backgrounds on click chemistry and magnetic materials.Chapter 2 presents a general method of loading small molecular organic catalysts onto hyper-crosslinked organic porous materials.A core-shell bottlebrush copolymer?PGM-g-?PLA-PS/PVBC??was used as the precursor and then turned to a chloromethyl-based organic porous polymer?Cl-MONNs?via a Friedel-Crafts hyper-crosslinking reaction.The chlorine atoms were further converted into azide groups to obtain N₃-MONNs.TEMPO molecules were then modified onto the tubular wall by click reaction.The structure and properties of TEMPO-MONNs were characterized by nitrogen adsorption-desorption isotherm,TEM and FT-IR,etc.Results show that the obtained material has a tubular network structure with surface area as 617.9 m²/g,pore volume as 1.01 cm³/g,and TEMPO loading amount as 0.34 mmol/g.TEMPO-MONNs are proved to be a high activity catalyst for the selective oxidation of benzyl alcohol and maintained a high conversion after 10 cycles.In order to prove that this method of loading the catalyst is universal,this chapter choose another small molecule catalyst DMAP and obtain DMAP-MONNs by click reaction similarly.A series of characterizations showed its porous structure and high specific surface area?534.7m²/g?.For the DMAP-MONNs,the esterification reaction was selected to test its catalytic activity which demonstrating that it has a high catalytic activity and can be recycled for 8 times.In Chapter 3,a magnetic-organic hollow sphere porous composite?Fe₃O₄@TBD-HMONs?with alkali-catalyzed activity was synthesized.A porous polymer with bromomethyl group?Br-HMONs?hollow sphere network structure was obtained using PLA-b-PS copolymer as the precursor.The co-precipitation method was used to introduce magnetic Fe₃O₄ nanoparticles into the hollow structure.Finally,TBD molecules were modified on the shell and abtained Fe₃O₄@TBD-HMONs.The material was characterized by nitrogen adsorption-desorption isotherm,TEM and FT-IR,magnetic test,elemental analysis,etc.It was proved that the magnetic-organic porous material has a core-shell structure with high surface area?602.1 m²/g?and TBD loading amount as 0.58 mmol/g.In order to test the catalytic activity of Fe₃O₄@TBD-HMONs,knoevenagel reaction was selected as a model reaction.It was found that Fe₃O₄@TBD-HMONs has high catalytic activity and can be magnetically efficiently separated and recycled for 8 times.