Postfunctionalization of Porous Organic Polymers Based on Friedel–Crafts Acylation for CO₂ and Hg²⁺ Capture

Abstract

Melamine-based porous organic polymers (POPs) are promising for gas uptake and water treatment because of their unique and tunable porosity, high nitrogen (N) content, and high Brunauer−Emmett−Teller (BET) surface area (S BET ). However, it is difficult to construct ketone-based POPs by the Friedel−Crafts acylation reaction. Herein, the ketone-based POPs were postfunctionalized with melamine (MA) by the Schiff-based reaction and the rigid triazine rings of MA were embedded in the polymer chains as rigid cross-linkers, resulting in the polymers with high S BET (555 m 2 •g −1 ) and total pore volume (0.72 cm 3 •g −1 ). Moreover, plentiful imine, amino, and triazine functionalities were inserted in the polymers, providing the polymers with high N content of 41.83 wt %. The resulting polymers were promising for CO 2 capture (145 mg• g −1 ; 273 K, 1.0 bar) and Hg 2+ removal (372 mg•g −1 ). This study offers a universal strategy to construct melamine-based POPs from various ketone-functionalized HCPs via a simple postfunctionalization.

Porphyrin-Based Nanoporous Organic Polymers for Adsorption of Carbon Dioxide, Ethane, and Methane

“…35 Moreover, this value greatly exceeds even that of Ni-Por-1 (137.7 mg/g), 40 despite the fact that Ni-Por-1 had a reported S BET value (1711 m 2 /g) more than double that of PNOP-1 (830 m 2 /g). Furthermore, the CO 2 uptake obtained by PNOP-1 also exceeds those obtained under the same testing conditions by many other microporous organic polymers, such as porous polybenzoxazole (PBO) (96−116 mg/g), 43 ketonefunctioned POPs (90−145 mg/g), 44 polypyrrole-based aerogel (PPA) (31 mg/g), 45 and triphenylamine-based polyaminal (TMP) networks (103−157 mg/g). 46 The results in Table 2 also indicate that the CO 2 adsorption capacities of the PNOPs at a temperature of 298 K are obviously less than those obtained at 273 K. This is because the nature of CO 2 adsorption on the PNOPs is physisorption.…”

Design, synthesis, and performance of adsorbents for heavy metal removal from wastewater: a review

“…Friedel–Crafts reactions could also be employed to synthesize a series of ketone-based HCPs which were post-functionalized with melamine (MA) through a Schiff-base reaction. 127 The triazine rings of MA offered rigid skeletons and plentiful nitrogen, affording various MA-based CMPs with a large surface area (up to 555 m 2 g −1 ) and high Hg( ii ) uptake (up to 372 mg g −1 ). Similarly, another triazine-based CMP (synthesized from MA and phthalate) obtained ample carboxyl and amino groups and thus displayed strong selectivity for Hg( ii ) over Fe( iii ), Cd( ii ), Ni( ii ), Zn( ii ), Ca( ii ), Mg( ii ), Na( i ), and K( i ).…”

Increasing the surface area and CO2uptake of conjugated microporous polymersviaa post-knitting method

“…20 In the past few years, many CMPs and HCPs with tunable nanopores, [21][22][23][24] various functional units [25][26][27][28][29][30] and a wide range of raw materials, [31][32][33] have been prepared. Additionally, to further improve the CO 2 uptake of these polymers, some commonly modified methods have been developed including carbonization, [34][35][36][37] post-functionalization [38][39][40][41] and composite processes. 42 However, CMPs and HCPs are still limited by the synthetic issue of the low surface area, which also brings about a large barrier to CCS technologies.…”