Efficient Purification of Ethylene from C₂ Hydrocarbons with an C₂H₆/C₂H₂-Selective Metal–Organic Framework

Abstract

The separation of ethylene (C2H4) from C2 hydrocarbons is considered as one of the most difficult and important processes in the petrochemical industry. Heat-driven cryogenic distillation is still widely used in the C2 hydrocarbons separation realms, which is an energy intensive process and takes up immense space. In response to a greener, more energy-efficient sustainable development, we successfully synthesized a multifunction microporous Mg-based MOF [Mg2(TCPE)­(μ2-OH2)­(DMA)2]·solvents (NUM-9) with C2H6/C2H2 selectivity based on a physical adsorption mechanism, and with outstanding stability; especially, it is stable up to 500 °C under an air atmosphere. NUM-9a (activated NUM-9) shows good performances in the separation of C2H6/C2H2 from raw ethylene gases. In addition, its actual separation potential is also examined by IAST and dynamic column breakthrough experiments. GCMC calculation results indicate that the unique structure of NUM-9a is primarily conducive to the selective adsorption of C2H6 and C2H2. More importantly, compared with C2H4, NUM-9a prefers to selectively adsorb C2H6 and C2H2 simultaneously, which makes NUM-9a as a sorbent have the capacity to separate C2H4 from C2 hydrocarbon mixtures under mild conditions through a greener and energy-efficient separation strategy.

Synergistic binding sites in a hybrid ultramicroporous material for one-step ethylene purification from ternary C 2 hydrocarbon mixtures

“…Another important dimension is that the altering of anion pillars (e.g., SiF 6 ) can induce the distortion of pore shapes and the rotation of organic ligands (14,15), thus anionpillared HUMs have emerged as the promising C 2 light hydrocarbon adsorbents for binary separations such as C 2 H 2 /C 2 H 4 (16), C 2 H 2 / CO 2 (17), and C 2 H 4 /C 2 H 6 (18). However, the single-step C 2 H 4 purification from ternary C 2 mixtures has never been achieved in adsorptive separations using anion-pillared HUMs, because the quadrupole moment and kinetic diameter of C 2 H 4 [1.5 × 10 −26 (5,(20)(21)(22)(23)(24)(25)(26)(27).…”

Rational Construction and Performance Regulation of an In(III)–Tetraisophthalate Framework for One-Step Adsorption-Phase Purification of C2H4 from C2 Hydrocarbons

“…Since Zhou and co-workers discovered the first MOF TJT-100 for simultaneous capture of C 2 H 2 and C 2 H 6 from C 2 H 4 , the potential of MOFs for such an application has still not been fully explored. To the best of our knowledge, only seven MOF compounds have been documented to date, − with limited uptake capacity and poor to moderate adsorption selectivity, primarily as a result of the lack of strong recognition sites simultaneously toward C 2 H 6 and C 2 H 2 . Therefore, there is a huge opportunity to increase the separation efficiency with respect to direct purification of C 2 H 4 via appropriately engineering the nanosized pore space and surface chemistry of MOFs.…”

Lanthanide–Organic Frameworks Featuring Three-Dimensional Inorganic Connectivity for Multipurpose Hydrocarbon Separation

“…For example, natural gas (NG) is composed mainly of methane (CH 4 ) but also includes various quantities of CO 2 as well as C 2 hydrocarbons. CO 2 /CH 4 and C 2 /C 1 separations thus present a major step toward NG purification, which avoids pipeline corrosion by acidic CO 2 and recovers C 2 hydrocarbon resources to increase its added values. − Apart from NG upgrading, C 2 H 4 purification is also a very important industrial process involving the capture from C 2 H 4 of its competing C 2 analogues, including acetylene (C 2 H 2 ) and ethane (C 2 H 6 ). − Due to their similar properties (Table S1), separation of C 2 H 4 from a trinary C 2 hydrocarbon mixture is extremely difficult. In addition, CO 2 as an impurity frequently exists in C 2 hydrocarbons.…”