Ultramicroporous Metal–Organic Framework with Inert Pore Surfaces for Inversed Separation of Ethylene from C₂ Hydrocarbons Mixtures

Abstract

The achievement of direct C 2 H 4 separation from C 2 hydrocarbons is very challenging in the petrochemical industry due to their similar molecular sizes, boiling points, and physicochemical properties. In this work, a nonpolar/inert ultramicroporous metal− organic framework (MOF), [Co 3 (μ 3 -OH)(tipa)(bpy 1), with stand-alone one-dimensional square tubular channels was successfully constructed, its pore enriched with plenty of aromatic rings causing nonpolar/inert pore surfaces. The MOF shows preferential adsorption of C 2 H 6 compared to C 2 H 4 and C 2 H 2 in the low-pressure region, which is further verified by adsorption heats and selectivities. The C 2 H 4 separation potential in one step for binary C 2 H 6 /C 2 H 4 (50/50 and 10/90) and ternary C 2 H 4 /C 2 H 6 / C 2 H 2 (89/10/1) is also examined by transient breakthrough simulations. Moreover, grand canonical Monte Carlo simulations demonstrate that the unique reversed adsorption mechanism is due to the shortest and most number of C−H•••π interactions between C 2 H 6 and the framework.

An ultramicroporous multi-walled metal–organic framework for efficient C2H2/CO2 separation under humid conditions

“…2b and c). The adsorption capacity of C 2 H 2 at 298 K is lower that of several benchmark MOFs such as SNNU-45 (134.0 cm 3 g −1 ), 36 FJU-90 (180 cm 3 g −1 ), 37 and UTSA-74 (103.5 cm 3 g −1 ) 38 (Table S1 †) but is comparable to that of other ultramicroporous MOFs, such as [Co 3 (m 3 -OH)(tipa)(bpy) 1.5 ]$ 3DMF$6H 2 O (39.5 cm 3 g −1 ), 39 PCPs-asp (36.7 cm 3 g −1 ), 40 Cu(bpy) NP (50.7 cm 3 g −1 ), 41 and Cu I @UiO-66-(COOH) 2 (51.7 cm 3 g −1 ). 42 It is worth noting that the slope of the C 2 H 2 adsorption isotherm at low pressure is steeper than that of CO 2 , indicating stronger interactions for C 2 H 2 with the framework.…”

Microporous Fluorinated MOF with Multiple Adsorption Sites for Efficient Recovery of C2H6 and C3H8 from Natural Gas

“…Metal–organic frameworks (MOFs) have shown great potential in gas adsorption and separation due to their high surface area, modified pores, adjusted topological structure, and high adsorption capacity, as compared to traditional porous materials like zeolites and activated carbon. − Several classic MOFs, including ZU-801, DUT-52, ZJU, , and DMOF, have exhibited excellent gas storage and separation performance. Researchers have made efforts to enhance gas adsorption and separation properties by functionalizing MOFs through the introduction of functional groups (−CH 3 , −NH 2 , −OH), tuning of pore size and the construction of open metal sites (OMSs). − Previous studies have shown that providing an appropriate aromatic pore environment can enhance interactions between light hydrocarbon molecules and the MOF framework through dispersion and induction forces, a widely used and effective approach. ,− Our research group is committing to the engineering of pores to achieve efficient gas capture. ,,, In our work, we aim to introduce additional functional sites into the aromatic pore environment to achieve a synergistic effect from multiple adsorption sites.…”