Nanoporous Fluorinated Covalent Organic Framework for Efficient C₂H₂/CO₂ Separation with High C₂H₂ Uptake

Abstract

Effective C 2 H 2 /CO 2 separation is regarded as a crucial procedure in the C 2 H 2 industry yet extremely challenging because of their similar physical and chemical properties. Covalent organic frameworks (COFs) have become a promising platform for gas adsorption separation, but they still suffer from unsatisfactory C 2 H 2 adsorption capacity and selectivity. Herein, we report a nanoporous fluorine-functioned COF (TpPa-F) for C 2 H 2 /CO 2 separation, which was synthesized by a mechanochemical approach with a F-containing precursor (2-fluoro-1,4-benzenediamine). A superior C 2 H 2 adsorption capacity of 117 cm 3 /g (4.78 mmol/g) and a C 2 H 2 / CO 2 selectivity of 3.3 at 298 K and 1 bar were achieved, which surpass most of the reported COF adsorbents in the literature. Notably, TpPa-F exhibited an extraordinary thermal stability of up to around 673 K and showed chemical robustness in organic or acidic/basic solutions. Theoretical calculations reveal the hydrogen bond interaction of C�C−H•••F, which contributes to the high C 2 H 2 uptake and separation selectivity. This work provides a promising strategy of fluorine functionalization for enhancing the ability to recognize and separate small gas molecules in a large channel.

Nanoporous Cu(II)-Adenine-Based Metal–Organic Frameworks for Selective Adsorption of C2H2 from C2H4 and CO2

“…The IAST adsorption selectivity of C 2 H 2 /C 2 H 4 for Cu-AD-SA is superior to those for Cu-AD-GA, NOTT-300, and the MOF-74 series MOFs (Table ) and approximates with that for HUST-6 but lower than those for the SIFSIX series, NBU-1 and MUF-17 . The IAST adsorption selectivities of C 2 H 2 /CO 2 for Cu-AD-SA are higher than those for HOF-5a and closer than those for Cu-AD-GA and UPC-200(Fe)-F-H 2 O but lower than those for CPOC-101α, FJU-6-TATB, HOF-FJU-8, ECUT-HOF-30, FJU-90, and TpPa-F (Table ). In addition to adsorption capacity and selectivity, stability and reproducibility for adsorption performance are also important indicators for evaluating the economic and effective separation potentials of porous materials.…”

Separation of High-Purity C2H2 from Binary C2H2/CO2 Using Robust Al-Based MOFs Comprising Nitrogen-Containing Heterocyclic Dicarboxylate

“…Acetylene (C 2 H 2 ) serves as a crucial feedstock in the petrochemical industry, essential for the production of a wide range of chemicals and polymers. , Additionally, it finds extensive utility as a fuel for gas-welding and cutting processes, accounting for a notable 20% of the total global consumption . The primary source of C 2 H 2 is derived from the cracking of petroleum, coal, or coal-derived coke, as well as the partial combustion of methane (CH 4 ), resulting in crude C 2 H 2 that contains CO 2 impurities. , Therefore, cryogenic distillation or extraction with an amine or basic solution is required to obtain a C 2 H 2 product with high purity levels exceeding 99.95%. However, these conventional processes are energy-intensive and present safety concerns related to explosion risks.…”

“…This approach stands as a promising alternative to conventional distillation and extraction techniques. Consequently, a wide array of porous materials have been investigated for the efficient production of high-purity C 2 H 2 through adsorption-based processes. − …”