Abstract:

Hyper-cross-linked polymers （HCPs） have been one of the hotspots of the porous organic polymers because of their high Brunauer-Emmett-Teller （BET） surface area （S_BET） and unique porosity. Moreover， their simple synthetic procedure of one-pot Friedel-Crafts reaction and various aromatic monomers make HCPs one of the hotspots of porpous organic polymers. Porphyrins are a kind of macromolecular heterocyclic compounds formed by the interlinking of four α-carbon atoms of pyrrole subunits via submethyl bridges. It can form stable complexes with a variety of metals， and has good applications in the adsorption and detection of heavy metals， adsorption and separation of gases， etc. However， the reported porphyrin-based HCPs in the literature are almost fabricated according to the Friedel-Crafts alkylation， while the Friedel-Crafts acylation reaction is rarely reported. The ketone-functionalized porphyrin-based HCPs based on the Friedel-Crafts acylation possess plentiful acyl groups， which offers a potential prospect for their further functionalization. However， these ketone-functionalized HCPs own very poor porosity， and their construction of unique porosity for this kind of HCPs is of great significance. Herein， the Friedel-Crafts acylation was performed for tetraphenylporphyrin and pyromellitic dianhydride， and the synthesized ketone-functionalized HCPs were further carried out for the Schiff-base reaction using melamine as the reactant. The resulting melamine-modified porphyrin-based HCPs exhibit medium S_BET （118 m²/g）， excellent hierarchical porosity， and high N content （46.28%）， indicative of its outstanding CO₂ capture and Hg²⁺ removal， the CO₂ uptake is 93 mg/g at 273 K and 101 kPa， and the Hg²⁺ adsorption reaches equilibrium within 30 min with the maximum capacity of 494.1 mg/g.

Key words: Melamine, Porphyrin, Friedel-Crafts acylation, Carbon dioxide capture, Hg（Ⅱ） ion removal