Search

Deep eutectic solvents (DESs) as promising green drying agents were first proposed to natural gas (NG) dehydration. In this work, choline chloride (ChCl)‐based DESs were prepared using ChCl as hydrogen bond acceptor (HBA) and triethylene glycol (TEG), ethylene glycol (EG) or Urea as hydrogen bond donors (HBDs). To explore the potential application, methane (CH4) dehydration experiment was conducted to verify the dehydration performance using prepared DESs. The thermodynamic properties were predicted by COSMO‐RS model (Conductor‐like screening model for real solvents). The quantum chemistry calculation was applied to understand the separation mechanism at the molecular level. The absorption performance of H2O in DESs depends on the weak interaction between Cl atom (or N and O atom) of ChCl and H atom of H2O as well as the free volume of DESs. Molecular dynamics (MD) simulation discloses the intermolecular interaction between HBA and HBD. This work makes the first multi‐scale analysis on NG dehydration using DESs. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs) as promising green absorbents were first proposed to capture the condensable cyclohexane gas. Choline chloride–ethylene glycol (EG) (Ethaline) and choline chloride–urea (Reline) were prepared using choline chloride as the hydrogen‐bond acceptor (HBA) and urea or EG as the hydrogen‐bond donor (HBD). To explore the potential application of DESs in condensable gas capture, the COSMO‐RS model was used to predict the solubility of cyclohexane in Ethaline and Reline. The thermodynamic properties, that is, Henry's constant and excess enthalpy, were estimated by correlating solubility data with Henry's law equation. Quantum chemical (QC) calculation was applied to understand the absorption mechanism at the molecular level. The results showed that the absorption performance of cyclohexane in Ethaline and Reline was dependent on the weak interaction between O of EG (or N of urea) and H of cyclohexane as well as the free volume effect of DESs. [ABSTRACT FROM AUTHOR]

• Preparation and characterization of new SUPRADES based on randomly methylated β-cyclodextrin. • Formation mechanism of SUPRADES revealed by molecular dynamics simulations at molecular level. • The physical absorption nature of VOCs in SUPRADES benefits recycling. • SUPRADES are promising absorbents to capture VOCs from industrial exhaust. The absorption of volatile organic compounds (VOCs) using supramolecular deep eutectic solvents (SUPRADES), composed of randomly methylated β-cyclodextrin (RAMEB) and conventional organic solvents, was systematically investigated from vapor-liquid experiments to molecular dynamic simulations. The obtained partition coefficients suggest that the combination of RAMEB and ethylene glycol (REG, mole ratio 1:40) significantly improves the absorption ability of ethylene glycol (EG), making REG even the most efficient absorbent for chloroform and limonene. By studying the key factors affecting the absorption process, we found that increasing the concentration of VOCs in the gas phase, lowering the absorption temperature or reducing the water content of the absorbent are effective in improving absorption. Regeneration test shows that the absorption ratio of chloroform using REG is maintained around 99% under six absorption–desorption cycles, highlighting its high absorption efficiency and stability. The absorption mechanism was then deeply explored by molecular dynamic simulation. It was found that the hydrogen bond between RAMEB and EG hinders the aggregation of neighboring RAMEB molecules, helping RAMEB to form stable and homogeneous solvent with EG. In addition, the interaction energy analysis demonstrates that van der Waals forces contribute the most to the absorption of chloroform by REG. Finally, the radical distribution function analysis was used to visualize the 2-dimensional molecule distribution of SUPRADES systems and the spatial distribution analysis verified the formation of RAMEB/chloroform inclusion complexes in the absorption process. The obtained results indicate that REG is a highly efficient and easy recyclable solvent for VOCs absorption. [ABSTRACT FROM AUTHOR]

• The absorption capacity of DESs for CH 2 Cl 2 was measured. • The removal ratio of DESs for CH 2 Cl 2 was investigated and compared. • Thermodynamic analysis for separation process was performed. • The separation mechanism was revealed at molecular level. A series of benzyl-based deep eutectic solvents (DESs) were successfully prepared and used for the capture of condensable dichloromethane gas. The COSMO-RS model was implemented to screen out the appropriate absorbent (i.e., DES TEBAC-TEG) for capturing dichloromethane. The physical properties of density and viscosity of DESs were measured to prove the feasibility of industrial application. The result of absorption experiment shows that TEBAC-TEG (the molar ratio 1:3) has big capacity of 581.72 mg/g with DCM partial pressure of 50 kPa at 303.15 K, and the removal ratio of dichloromethane reached 91.65 %. Further, the absorption mechanism was revealed by Gibbs free energy analysis and quantum chemical calculations. It was found that both chloride ion and TEG displayed high hydrogen bond (HB) acceptance ability, which could form HB with dichloromethane to enhance the absorption process. Particularly, the C H⋅⋅⋅π interaction is dominant between TEBA cation and dichloromethane molecule. [ABSTRACT FROM AUTHOR]