Copper(I)-Catalyzed Synthesis of Nanoporous Azo-Linked Polymers: Impact of Textural Properties on Gas Storage and Selective Carbon Dioxide Capture

Abstract

A new facile method for synthesis of porous azo-linked polymers (ALPs) is reported. The synthesis of ALPs was accomplished by homocoupling of aniline-like building units in the presence of copper(I) bromide and pyridine. The resulting ALPs exhibit high surface areas (SABET = 862–1235 m2 g–1), high physiochemical stability, and considerable gas storage capacity especially at high-pressure settings. Under low pressure conditions, ALPs have remarkable CO2 uptake (up to 5.37 mmol g–1 at 273 K and 1 bar), as well as moderate CO2/N2 (29–43) and CO2/CH4 (6–8) selectivity. Low pressure gas uptake experiments were used to calculate the binding affinities of small gas molecules and revealed that ALPs have high heats of adsorption for hydrogen (7.5–8 kJ mol–1), methane (18–21 kJ mol–1), and carbon dioxide (28–30 kJ mol–1). Under high pressure conditions, the best performing polymer, ALP-1, stores significant amounts of H2 (24 g L–1, 77 K/70 bar), CH4 (67 g L–1, 298 K/70 bar), and CO2 (304 g L–1, 298 K/40 bar).

Bifunctionalized conjugated microporous polymers for carbon dioxide capture

“…Both of the polymer networks exhibited low gas coverage enthalpies of adsorption of around 7.8 kJ/mol (Fig. S7), which is comparable to the nonfunctionalized CMPs (7À10 kJ/mol) [36], the lithium doped CMP (8.1 kJ/mol) [46], the lithium modified covalent-organic polymer (~7.6 kJ/mol) [47], the porous benzimidazole-linked polymer (7.9e8.3 kJ/mol) [48], and the nanoporous azo-linked polymers (7.5e8.0 kJ/mol) [34]. The CO 2 uptakes of the polymer networks were measured up to 1.13 bar at 273 and 298 K, respectively (Fig.…”

“…1.80 mmol g À1 for CMP-1-(OH) 2 ) [17], the triazinefunctionalized CMPs (e.g. 2.62 mmol g À1 for TNCMP-2) [50], the amide-functionalized CMP of CMP-1-AMD1 (1.51 mmol g À1 ) [26], although it is still low in comparison with some other MOPs with high CO 2 uptake ability, such as the nanoporous azo-linked polymer of ALP-1 (236 mg g À1 ,~5.36 mmol g À1 ) [34], the polyaminetethered porous polymer network of PPN-6-CH2DETA (4.3 mmol g À1 at 295 K/1.0 bar) [24], the porous benzimidazolelinked polymer of BILP-4 (235 mg g À1 ,~5.34 mmol g À1 ) [48], the microporous polycarbazole of CPOP-1 (21.2 wt %,~4.8 mmol g À1 ) [51], the imine-linked porous polymer framework of PPF-1 (6.1 mmol g À1 ) [52], and the benzimidazole-incorporated porous polymer network of PPN-101 (5.1 mmol g À1 ) [53]. The relative high CO 2 uptake capacity of the BFCMPs could be attributed to the high surface area, and as well the introduction of polar functional groups (hydroxyl and sultone groups) into the polymer skeleton enhanced the binding affinity between the polymers and CO 2 molecules.…”

“…S10 and S11). Both of the bifunctionalized polymer networks showed very similar adsorption selectivities of 4.0 for CO 2 /CH 4 and 30 for CO 2 /N 2 at 273 K. The CO 2 / N 2 adsorption selectivity by both of the polymer networks is comparable to that of some other MOPs under the similar conditions, such as the triazine-functionalized CMPs (9.0e25.2 at 298 K) [50], the amide-functionalized CMPs (8.5e12 at 298 K) [26], the imine-linked porous polymer frameworks (14.5e20.4 at 273 K) [52], the carbazolic porous organic frameworks (19À37 at 273 K) [58], and the nanoporous azo-linked polymers (30e43 at 273 K) [34], though it is lower than that of some other reported MOPs with the CO 2 /N 2 adsorption selectivity higher than 100, such as the azobridged covalent organic polymer of Azo-COP-2 with a CO 2 /N 2 adsorption selectivity of 109 at 273 K [59], the porous benzimidazole-linked polymer of BILP-2 with a CO 2 /N 2 adsorption selectivity of 113 at 273 K [48], the PPN-6-SO 3 NH 4 with a CO 2 /N 2 adsorption selectivity of 196 at 295 K, and the tri(4-ethynylphenyl) amine-based porous aromatic framework with amine groups of PAF-33eNH 2 with the CO 2 /N 2 adsorption selectivity as high as 250 at 273 K [29]. However, the absolute amount of CO 2 adsorbed was only 1.19 mmol g À1 for PAF-33eNH 2 at 273 K/1.0 bar [29], much lower than that of the BFCMP-2 (2.77 mmol g À1 at 273 K/1.13 bar) in this work.…”

Bottom-up Approach for the Synthesis of a Three-Dimensional Nanoporous Graphene Nanoribbon Framework and Its Gas Sorption Properties

“…We found exceptional CO 2 /CH 4 selectivities of 52.5 and 62.7 at 1 bar, 298 K for pre-GNF and GNF-1. GNF-1 showed the highest CO 2 /CH 4 selectivity compared to recently reported nitrogen containing nanoporous polymers such as, Li-POPs 29 , PAF-30 (24.3-30.2) 26 , ALP (4-8) 52 and NPOFs (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) 55 . The CO 2 /CH 4 selec- tivity of GNF-1 is also very high compared to the activated carbon (3.7) 56 , thus showing clearly the promise of our bottom-up approach for the preparation of carbon-based frameworks.…”

Porous carbon derived via KOH activation of a hypercrosslinked porous organic polymer for efficient CO2, CH4, H2 adsorptions and high CO2/N2 selectivity

“…and thus porous carbons are investigated intensively over the years [6][7][8]. N-rich, hydroxy (-OH) functionalized porous organic polymers with high BET surface areas have attracted widespread interest today as selective adsorbents for CO 2 [9][10][11][12][13][14][15]. Physical or chemical activation of carbonaceous materials with CO 2 , steam, ZnCl 2 , KOH etc.…”