The highly efficient separation of C2H6/C2H4 meets great challenges due to their similar physicochemical property and molecular dimension. Herein, pure-silica MFI zeolite was incorporated with different heteroatoms (Mn, Cu, Ni, Zn) to achieve appropriate surface polarity. The results showed that the Mn sites in the zeolite frameworks could enhance both the affinity toward C2H6 and C2H4. Additionally, the P modification over Mn-containing MFI zeolites were conducted to restrict the electron transfer effect of Mnδ+ species. Notably, with the P contents increased to 0.75 wt%, the C2H4-favored separation behaviour was reversed to the C2H6-favored one. The isosteric adsorption heat and desorption active energy confirmed that the strong C2H6 affinity on the zeolite surface, which could verify the reverse process. Finally, the XPS spectra, Raman spectra and GCMC simulations further proved that the bonding between P and Mn could decrease the structural defects and weaken the electron transfer of Mnδ+ species within the functionalized zeolite, which exhibited significant impacts on the preferential capture of C2H6 versus C2H4 molecules. As such, an optimal trade-off between the dynamic C2H6/C2H4 separation selectivity and C2H6 uptake was realized by the cooperative strategy of Mn incorporation and P modification.
A series of dual functionalized ionic liquids with metal chelate cations from surfactant and alkali metal salt were designed, prepared, and used for SO2 capture. The effect of metal ions, coordination number, anionic structures, temperature, and pressure on SO2 absorption was investigated. The interaction of these functionalized ionic liquids with SO2 was explained by spectroscopic investigation. The results showed that these metal-containing ionic liquids exhibited high absorption capacity through a combination of physical and chemical interaction of SO2 with basic anions and ether-containing cations as well as excellent reversibility (21 recycles). Considering the easy preparation, low cost, and excellent performance, these dual functionalized metal-containing ionic liquids provide significant improvements over traditional ionic liquids, indicating the promise for industrial application in SO2 capture.
Abstract Porous liquids are a newly developed porous material that combine unique fluidity with permanent porosity, which exhibit promising functionalities for a variety of applications. However, the apparent incompatibility between fluidity and permanent porosity makes the stabilization of porous nanoparticle with still empty pores in the dense liquid phase a significant challenging. Herein, by exploiting the electrostatic interaction between carbon networks and polymerized ionic liquids, we demonstrate that carbon‐based porous nanoarchitectures can be well stabilized in liquids to afford permanent porosity, and thus opens up a new approach to prepare porous carbon liquids. Furthermore, we hope this facile synthesis strategy can be widely applicated to fabricate other types of porous liquids, such as those (e.g., carbon nitride, boron nitride, metal–organic frameworks, covalent organic frameworks etc.) also having the electrostatic interaction with polymerized ionic liquids, evidently advancing the development and understanding of porous liquids.
Carbon capture and storage (CCS) and carbon capture and utilization (CCU) are two kinds of strategies to reduce the CO2 concentration in the atmosphere, which is emitted from the burning of fossil fuels and leads to the greenhouse effect. With the unique properties of ionic liquids (ILs), such as low vapor pressures, tunable structures, high solubilities, and high thermal and chemical stabilities, they could be used as solvents and catalysts for CO2 capture and conversion into value-added chemicals. In this critical review, we mainly focus our attention on the tuning IL-based catalysts for CO2 conversion into quinazoline-2,4(1H,3H)-diones from o-aminobenzonitriles during this decade (2012~2022). Due to the importance of basicity and nucleophilicity of catalysts, kinds of ILs with basic anions such as [OH], carboxylates, aprotic heterocyclic anions, etc., for conversion CO2 and o-aminobenzonitriles into quinazoline-2,4(1H,3H)-diones via different catalytic mechanisms, including amino preferential activation, CO2 preferential activation, and simultaneous amino and CO2 activation, are investigated systematically. Finally, future directions and prospects for CO2 conversion by IL-based catalysts are outlined. This review is benefit for academic researchers to obtain an overall understanding of the synthesis of quinazoline-2,4(1H,3H)-diones from CO2 and o-aminobenzonitriles by IL-based catalysts. This work will also open a door to develop novel IL-based catalysts for the conversion of other acid gases such as SO2 and H2S.
Preserving the structural and functional integrity of interfaces and inhibiting deleterious chemical interactions are critical for realizing devices with sub-50 nm thin films and nanoscale units. Here, we demonstrate that ∼0.7-nm-thick self-assembled monolayers (SAMs) comprising mercapto-propyl-tri-methoxy-silane (MPTMS) molecules enhance adhesion and inhibit Cu diffusion at Cu/SiO2 structures used in device metallization. Cu/SAM/SiO2/Si(001) structures show three times higher interface debond energy compared to Cu/SiO2 interfaces due to a strong chemical interaction between Cu and S termini of the MPTMS SAMs. This interaction immobilizes Cu at the Cu/SAM interface and results in a factor-of-4 increase in Cu-diffusion-induced failure times compared with that for structures without SAMs.
Ionic liquids (ILs) with a reversible hydrophobic-hydrophilic transition were developed, and they exhibited unique phase behavior with H2O: monophase in the presence of CO2, but biphase upon removal of CO2 at room temperature and atmospheric pressure. Thus, coupling of reaction, separation, and recovery steps in sustainable chemical processes could be realized by a reversible liquid-liquid phase transition of such IL-H2O mixtures. Spectroscopic investigations and DFT calculations showed that the mechanism behind hydrophobic-hydrophilic transition involved reversible reaction of CO2 with anion of the ILs and formation of hydrophilic ammonium salts. These unique IL-H2O systems were successfully utilized for facile one-step synthesis of Au porous films by bubbling CO2 under ambient conditions. The Au porous films and the ILs were then separated simultaneously from aqueous solutions by bubbling N2, and recovered ILs could be directly reused in the next process.
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