Hypercrosslinked porous polyporphyrin by metal-free protocol: characterization, uptake performance, and heterogeneous catalysis

Abstract

Through metal-free protocol, hypercrosslinked porous polyporphyrin with permanent porosity was obatined via the Friedel–Crafts alkylation of tetracarbazolylporphyrin using formaldehyde dimethyl acetal as an external cross-linker. Its chemical structure and porosity was well characterized and confirmed. The BET specific surface area value of HCP-TCPP is 1050 m2 g−1 and related dominant pore size is centered at 0.63 nm. The adsorption amount of methanol by HCP-TCPP is high up to 800 mg g−1 (about 25.0 mmol g−1) at its saturated vapor pressure, which is higher than that of toluene (600 mg g−1, 6.5 mmol g−1). Further study indicates that polymer HCP-TCPP, possessing the high BET specific surface area and total pore volume, exhibits good hydrogen uptake of 3.44 wt % (77 K) and high carbon dioxide uptake of 41.1 wt % (298 K) at 18.0 bar. Besides, the obtained porous polymer can also be used as an effective heterogeneous catalyst for the Knoevenagel condensation between various aldehydes and malononitrile.

Keywords

• Adsorption
• catalysis
• hypercrosslinking
• porous polymers
• porphyrin