Methane Uptakes in Covalent Organic Frameworks with Double Halogen Substitution

Abstract

The methane uptakes of six double halogen substituted covalent organic frameworks (COFs) based on COF-102 were simulated with grand canonical Monte Carlo simulation at 298 K and pressure ranges from 1 to 80 bar. The simulation shows that COF-102-1,4-2I reaches the DOE target of 180 V(STP)/V for methane delivery. The current study highlights the correlation between the structure and the adsorption property of the double halogen substituted COF-102. In COF-102-1,4-2I, the triangle arrangement of the six I atoms around the central B3O3 ring brings close contact between I atom and B3O3 ring, and thus enhances the attraction of CH4 with high CH4 density in the vicinity above and below this region, especially in particular adsorption sites. Such favorable structural arrangement, altogether with the strongest I–CH4 attraction among the halogen substituent in this study, gives the highest isosteric heat as well as the CH4 uptakes at 298 K and 35 bar in the hypobaric region. The result in this study demonstrates that double halogen substituted COF-102 is capable of increasing CH4 uptakes for practical applications.

Vapor-phase linker exchange of metal-organic frameworks

“…There was no direct contact between ZIF-8 and IIM. For linker exchange, the autoclave was heat-treated at 150°C for a certain period of time (1,3,6,12,24,48, and 72 hours). After natural cooling to room temperature, the exchanged ZIF-8/I was obtained.…”

Postsynthetic Covalent Modification in Covalent Organic Frameworks

“…Generally, these COFs were obtained under relatively higher temperature (up to 200 °C) with pronounce thermal and chemical stabilities. Another C and N aromatic (C−N aromatic ) linkage was also involved in synthesizing COFs resulting in dimerization (phenazine, imidazole) and cyclo‐trimerization (triazine) based COFs. The sp 2 ‐carbon (C=C) linkage has also been realized in COF synthesis which adopted the structural backbone of 2D graphene .…”

Design of Zeolite-Covalent Organic Frameworks for Methane Storage

“…That was, COF-103-Eth-trans and COF-102-Ant with methane adsorption capacity exceeding the target set by the DOE ( Figure S1). Another group, Jing Hao Hu et al, modified COF-102 with a double halogen substitution [26]. Their simulation result shows that the methane adsorption capacity of COF-102-1,4-2I is 181 V (STP)/V.…”