Highly stable nanoporous covalent triazine-based frameworks with an adamantane core for carbon dioxide sorption and separation

Abstract

Adamantane substituted with two to four 4-cyanophenyl groups was used for preparation of a new series of robust Porous Covalent Triazine-based Framework (PCTF) materials. Novel adamantane PCTFs were synthesized in good yields (>80%) by the trimerization reaction of 1,3-bis-, 1,3,5-tris-and 1,3,5,7tetrakis(4-cyanophenyl)adamantane, respectively, in the presence of ZnCl 2 (Lewis acid condition) and CF 3 SO 3 H (strong Brønsted acid condition). From N 2 adsorption isotherms, the Lewis acid condition gives higher surface areas than the strong Brønsted acid condition. The amorphous nano-to microporous frameworks (>50% micropore fraction) exhibit excellent thermal stabilities (>450 C) with BET surface areas up to 1180 m 2 g À1 . A very similar ultramicropore size distribution between 4 and 10 Å was derived from CO 2 adsorption isotherms with a "CO 2 on carbon based slit-pore model". At 1 bar the gases H 2 (at 77 K), CO 2 (at 273 and 293 K) and CH 4 (at 273 K) are adsorbed up to 1.24 wt%, 58 cm 3 g À1 and 20 cm 3 g À1 , respectively. Gas uptake increases with BET surface area and micropore volume which in turn increase with the number of cyano groups in the monomer. From single component adsorption isotherms, IAST-derived ideal CO 2 :N 2 , CO 2 :CH 4 and CH 4 :N 2 selectivity values of up to 41 : 1, 7 : 1 and 6 : 1, respectively, are calculated for p / 0 at 273 K. The adamantane PCTFs have isosteric heats of adsorption for CO 2 of 25-28 kJ mol À1 at zero loading and most of them also >25 kJ mol À1 over the entire adsorption range which is well above the heat of liquefaction of bulk CO 2 or the isosteric enthalpy of adsorption for CO 2 on activated carbons.

Carbonization of covalent triazine-based frameworks via ionic liquid induction

“…This behavior is attributed to the consumption of the monomer during the reactions. The peaks at 1523 and 1351 cm -1 in KPOP-6a and KPOP-6b's spectra confirm the formation of triazine rings 11,[35][36][37] while the very weak intensity of the corresponding peaks in the spectra of KPOP-6c, KPOP-6d, and KPOP-6e is indicative of the triazine decomposition. …”

“…Porous organic polymers (POPs), an inorganic node free version of porous materials (including crystalline covalent organic frameworks (COFs), 6 and amorphous porous aromatic frameworks (PAFs), 7 polymers of intrinsic microporosity (PIMs), 8 porous polymer networks (PPNs), 9 covalent triazinebased frameworks (CTFs) [10][11][12][13][14][15][16][17][18][19] ) are attracting more and more attention because of their great potential for practical applications, for example, gas storage, separation, catalysis, and electronic device. 20 Among these materials, CTFs can be obtained by using a cheap catalyst such as ZnCl 2 and possess high chemical and thermal stability.…”

Conversion of amorphous polymer networks to covalent organic frameworks under ionothermal conditions: a facile synthesis route for covalent triazine frameworks

“…[9][10][11][12][13][14][15][16][17][18][19][20] CTFs have also been applied as solid base catalysts for the conversion of CO 2 21 and as metal free catalysts for ORR. 22,23 The high surface area and nitrogen amount make CTFs attractive for the storage of gases 6,[24][25][26][27][28] or generally as sorbent materials. [29][30][31] Furthermore, due to the conjugated planar structure, CTFs are organic semiconductors.…”

Preparation and Characterization of the Phthalazinone Structure-based Microporous Organic Polymer

“…Molten ZnCl 2 acts as a Lewis acid catalyst, molten solvent and porogen for the polymerization_ENREF_14 [11]. The high-temperature trimerization of aromatic nitrile groups catalyzed by ZnCl 2 would form a C 3 N 3 triazine ring，which can be marked as a triangular ring.…”

“…CTFs exhibit large specific surface areas, as well as remarkable thermal stabilities, tunable pore sizes, and high gas adsorption capacities [3][4]. In addition, CTFs have been used in heterogeneous catalysis, as a catalytic support in liquid phase reactions, for gas storage and separation of organic dyes [11]. .…”