Preparation of Porous Organic Polymer through Nuclephilic Substitution Polymerization between Dichloromaleimide and Aromatic Amine

Porous organic polymer (POP) has attracted great interests due to its excellent pore tunability and diverse synthetic methods, and has been widely used in the fields of gas storage, carbon capture, separation, catalysis, sensing, energy storage and conversion. However, most of the POPs are prepared from expensive monomers and noble metal catalysts which usually require complicated workup thus rise the cost and reduce the synthetic efficiency. It is necessary to explore some novel precious-metal-free and workup-easy polymerization reactions to obtain POP efficiently. In this work, the monomer 1, 2-bis(3, 4-dichloromaleimidyl)-hexane was firstly synthesized from the reaction of 1, 2-diaminocyclohexane and dichloromaleic anhydride. The POP was further synthesized through nucleophilic substitution polymerization between 1, 2-bis(3, 4-dichloromaleimidyl)-hexane and 1, 3, 5-tris-(4-aminophenyl) with acetic acid as solvent. Fourier Transform Infrared spectroscopy (FT-IR) indicates the formation of C-N bonds between dichloromale imide and aromatic amine units. Nitrogen adsorption-desorption isotherm shows that the prepared POP has a high surface area (404 m²/g) and a wide range of pore size distribution from 1 nm to 6 nm (containing micropore and mesopore). In addition, Scanning Electron Microscopy (SEM) shows that the prepared POP has a regular rod structure (diameter, 1-5 μm). The thermogravimetric analysis (TG) reveales that the POP has excellent thermal stability (degration temperature is up to 400℃). As a novel catalyst-free and workup-easy C-N coupling reaction, the developed nucleophilic substitution polymerization between dichloromale imide and aromatic amine works well to synthesize maleic amide-based POP efficiently, and it is an eco-friendly C-N crossing strategy which can provide people another choice to obtain the targeted POP free of catalysts efficiently.