Recovering C 2 H 4 from refinery gas is an effective way to broaden the source of ethylene. However, it's a challenging task to separate C 2 H 4 and C 2 H 6 due to their very close physical properties and molecular size. Metal-organic frameworks (MOFs) are shown broad prospects in the field of light hydrocarbon separation in recent years. In this work, NH 3 is used to modify the structure of UTSA-280, the efficient separation of C 2 H 4 /C 2 H 6 can be achieved through the adjustment of one-dimensional channels. UTSA-280 has undergone stepwise adsorption of ammonia gas at 298 K and 100 kPa. After partial ammonia removal, we obtained the modified UTSA-280 that ammonia adsorption modification with a mass loading of 5.6% for UTSA-280-M1 and 2.8% for UTSA-280-M2. The NH 3 modified UTSA-280 shows a unique ultramicroporous structure that can enhance the adsorption of C 2 H 4 and does not adsorb the slightly larger C 2 H 6 , achieving the ideal C 2 H 4 /C 2 H 6 adsorption selectivity (more than 1000). Ammonia molecules play the role of perfectly adjusting the size of one-dimensional channels and realize the ideal screening effect of C 2 H 4 /C 2 H 6 . The C 2 H 4 adsorption capacity of NH 3 modified UTSA-280-M2 can be improved to 2.83 mmol/g at 298 K and 100 kPa (an increase of 29% compared with initial material). And its ultramicroporous structure can fully block the adsorption of C 2 H 6 , which finally achieves a C 2 H 4 /C 2 H 6 selectivity over 1200. Grand Canonical Monte Carlo (GCMC) simulation of C 2 H 4 /C 2 H 6 mixed gases (equal volume) adsorption results showed that the modified UTSA-280 had more C 2 H 4 adsorption distribution in the mixed components than C 2 H 6 . Through the C 2 H 4 /C 2 H 6 mixed gases breakthrough test at 298 K, NH 3 modified UTSA-280-M2 shows a separation time of more than 48 min, which is more than the initial 25 min. Compared with the unmodified material, the separation performance is nearly doubled. Scalable synthesis, stable structure, and the advantages of controllable performance after ammonia modification have prompted this material to have great prospects in the industrialization of C 2 H 4 /C 2 H 6 separation. Keywords metal-organic frameworks; NH 3 modification; C 2 H 4 /C 2 H 6 separation; selectivity

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A copper nanoparticles-catalyzed three-component coupling reaction of alkyne, dihalomethane, and amine (AHA coupling) was reported for the synthesis of propargylic amine. The catalytic AHA coupling reaction was carried out under mild conditions with dihalomethane as substrate and solvent, and good to excellent yields were also achieved. Furthermore, the nanoparticle catalyst could be recovered and reused effectively, and no obvious reduction on catalytic activity was observed for five recycles.

In this work, the competitive adsorption behavior of H₂ and CO on strained Fe(110) are investigated by the first-principles method based on the spin-polarized density functional theory to study the hydrogen embrittlement of steels. The results show that the most stable adsorption site for CO is top site, and the orbital of CO molecule hybridizing with Fe 3p and 4s states illustrates a strong electronic interaction between them. The adsorption energy values of CO at the four calculated adsorption sites are more negative than those of H₂, which favors the binding with Fe(110) surface. The potential energy variations for CO and H₂ molecules close to the surface are calculated. The attractive force of the Fe(110) surface acting on CO in 1.5–3 Å is greater than that acting on H₂. The pre-adsorbed CO increases the dissociation energy barrier of H₂ from 0.08 eV to 0.13 eV but reduces the force between H₂ and surface. The surface tensile strain enhances the interaction between hydrogen and Fe(110), which, however, is reduced by the compressive strain. The opposite tendency is found in the adsorption of CO. The binding strength of CO is stronger than that of H₂ on the strained Fe(110) surface. The difference in adsorption energy between CO and H₂ decreases with tensile strain increasing. The effect of surface strain and partial pressure of CO gas phase on the surface coverage ratio of H atom are also calculated quantitatively based on thermodynamics at 298 K, with the partial pressure of H₂ set to be 10 MPa. The surface ratio of the H atom decreases with partial pressure of CO increasing. The hydrogen coverage drops nearly to zero when the partial pressure of CO reaches a certain value. This result reveals that CO can inhibit hydrogen adsorption on Fe surface. In the case where the surface ratio of hydrogen decreases to 1%, the corresponding CO partial pressures are 105 Pa, 1.1 × 10³ Pa, 2.4 × 10⁵ Pa on –2%, 0, 2% strained Fe(110) surface, respectively. High CO partial pressure is needed to suppress the hydrogen adsorption since the binding strength of CO is close to that of H₂ on the expanded surface.

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