One‐Step C₂H₄Purification from Ternary C₂H₆/C₂H₄/C₂H₂Mixtures by a Robust Metal–Organic Framework with Customized Pore Environment

Abstract

One-step C 2 H 4 purification from ternary C 2 H 6 / C 2 H 4 /C 2 H 2 mixtures by a single adsorbent is of great industrial significance, but few adsorbents achieve this separation. Herein, we report a robust metal-organic framework (MOF) that possesses methyl-decorated nonpolar pores and shows one-step C 2 H 4 purification (purity > 99.9 %) from binary C 2 H 6 /C 2 H 4 mixtures and ternary C 2 H 6 /C 2 H 4 /C 2 H 2 mixtures. The methyl groups in pores provide a suitable pore environment to simultaneously enhance the adsorption capacity for C 2 H 2 and C 2 H 6 compared to C 2 H 4 . Simulations revealed the multiple interactions between C 2 H 6 or C 2 H 2 molecules and the pore wall, while the interactions with C 2 H 4 molecules are weak and also unfavorable due to the repulsion from methyl groups in pores. The MOF displays high C 2 H 6 and C 2 H 2 uptakes and benchmark C 2 H 6 /C 2 H 4 selectivity (2.2), surpassing all of the reported MOFs for one-step C 2 H 4 purification from ternary C 2 H 6 /C 2 H 4 /C 2 H 2 mixtures.

Enhanced one‐step purification of C2H4 from C2H2/C2H4/C2H6 mixtures by fluorinated Zr‐MOF

“…and UiO-66-(CF 3 ) 2 (1.1 and 1.4). The values are also comparable to the benchmark adsorbent capable of one-step purification of C 2 H 4 from the C 2 H 2 /C 2 H 4 /C 2 H 6 mixture (Figure3F) 7,8,21,[28][29][30][31][32][33][34][35]. The selectivities of C 2 H 2 /C 2 H 4 (1/99; v/v) and C 2 H 6 /C 2 H 4(10/90; v/v) were also calculated which are close to the values for equimolar mixtures (Figure S5).…”

Pillar-layer Zn–triazolate–dicarboxylate frameworks with a customized pore structure for efficient ethylene purification from ethylene/ethane/acetylene ternary mixtures

“…2d). 3,[12][13][14][15][16][25][26][27][28][29][30][31][32] The isosteric heats of adsorption (Q st ) of C 2 H 2 , C 2 H 4 and C 2 H 6 on HIAM-210 were determined by using the Virial equation (Fig. S8 and S9 †).…”

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

“…The appearance of physical adsorbents is hopeful of greatly reducing the energy consumption of the purification process, which has the potential to replace traditional cryogenic distillation. − Metal–organic frameworks (MOFs) as novel porous materials can be precisely regulated and designed to obtain desired pore sizes and environments at the molecular level through crystal engineering approaches. − In general, most MOF materials exhibit the outstanding adsorption of unsaturated C 2 hydrocarbons with the relationship of adsorption capacities and affinity order of C 2 H 2 > C 2 H 4 > C 2 H 6 because introducing open metal sites/clusters or polar groups on the pore surfaces of MOFs can give priority to binding molecules with high dipole and/or quadrupole moments (quadrupole moments of 7.2 × 10 –26 esu cm 2 for C 2 H 2 , 1.5 × 10 –26 esu cm 2 for C 2 H 4 , and 0.65 × 10 –26 esu cm 2 for C 2 H 6 ). − In addition, the kinetic diameter of C 2 H 4 (4.163 Å) is between C 2 H 6 (4.443 Å) and C 2 H 2 (3.3 Å), so molecular sieving by adjusting the pore aperture cannot be implemented . Therefore, the achievement of direct C 2 H 4 separation in one step is a more challenging and desirable target − because high-purity C 2 H 4 can be directly produced without an extra desorption step, thus avoiding a great deal of energy consumption.…”

“…25−29 In addition, the kinetic diameter of C 2 H 4 (4.163 Å) is between C 2 H 6 (4.443 Å) and C 2 H 2 (3.3 Å), so molecular sieving by adjusting the pore aperture cannot be implemented. 30 Therefore, the achievement of direct C 2 H 4 separation in one step is a more challenging and desirable target 31−33…”