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Ionic liquids (ILs) are promising solvents for separating aromatics from fuel oils. However, studies for separate polycyclic aromatics with ILs are rare and insufficient, and the impact of solute structure on extraction performance still needs to be determined. In this work, we use 1‐ethyl‐3‐methylimidazolium bis([trifluoromethyl]sulfonyl)imide ([EMIM][NTF2]) as an extractant to separate 1‐methylnaphthalene, quinoline, and benzothiophene from dodecane mixtures. Liquid–liquid equilibrium experiments identified the optimal operating conditions. Nine solute molecules, including five alkanes and four aromatic hydrocarbons, were used to study the relationship between extraction performance and solute structure. Molecular dynamics simulation and quantum chemistry calculations gave a deep insight and reasonable interpretation of the structure‐performance relationship at the molecular level. An industrial‐scale extraction process was proposed. The IL can be easily regenerated using heptane as a back‐extractive solvent. A high‐purity fuel oil with aromatic content below 0.5 wt% is obtained after 8‐stage extraction. [ABSTRACT FROM AUTHOR]

With the rapid development of the semiconductor industry, the demand for ultraclean and high‐purity electronic chemicals, especially ultrapure water as a general solvent for cleaning semiconductor chips, has increased dramatically. The distillation process is a good choice for large‐scale production of ultrapure water that can be used to clean semiconductor chips, but there is a lack of basic thermodynamic theory for removing ionic impurities. In this work, the temperature and vapor–liquid phase composition of sodium and potassium salts aqueous solutions at vapor–liquid equilibrium (VLE) were investigated by experiments. The microstructure of each inorganic salt aqueous solution was explored by molecular dynamics simulation and quantum chemical calculation, and the interaction between each ion and water molecule was analyzed. A volatilization mechanism of inorganic salts was proposed, and it was found that the volatilization of inorganic salts in an aqueous solution was affected by the strength of interaction between the dissociated anions and cations and water molecules. Finally, the conductor‐like screening model segment activity coefficient (COSMO‐SAC) model predicted the VLE values of inorganic salt aqueous solutions. The prediction at low concentrations (xs < 0.06) was in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Using new green solvents to effectively capture volatile organic compounds (VOCs) is considered as an attractive green sustainable chemical development route. In this work, benzene, toluene, ethylbenzene and p-xylene (BTEX) were selected as typical aromatic VOCs. The gas absorption performance of proton [MIM][NTF 2 ] and aprotic [EMIM][NTF 2 ] ionic liquids (ILs) for BTEX were studied by computational thermodynamics combined with gas absorption experiments. Absorption experiments of BTEX and regeneration experiments of ILs were carried out at different temperatures, and ILs had good stability. The interaction type and intensity were determined by Interaction Region Indicator (IRI) analysis of IL-BTEX blend systems. The C-H···π and π-π interaction between imidazole ring and BTEX were the direct reason why ILs can efficiently absorb BTEX. Molecular dynamics simulations were performed to explore the diffusion behavior of gas in ILs. The increase of methyl group increases the interaction strength of the system, and the fractional free volume of IL-BTEX blend systems decreases gradually, which limits the diffusion of BTEX. Non-bond interaction analysis shows that van der Waals interaction was the main driving force of BTEX absorption in ILs. • Protic [MIM][NTF 2 ] and aprotic [EMIM][NTF 2 ] ILs were proposed to enhance the capture of BTEX. • PIL and AIL still maintained good absorption effect after 5 adsorption-desorption cycles. • The C-H···π and π-π interaction is the main interaction between ILs and BTEX. • The diffusion behavior of gas in ILs was revealed by MD simulations and FFV theory. • van der Waals interaction is the main driving force of BTEX absorption in ILs. [ABSTRACT FROM AUTHOR]

• A control test was carried out based on the prediction results of COSMO-RS model. • Extraction efficiency of TP and BTP by TEAC:PrA were 98.06 % and 98.53 %, respectively. • The structure–activity relationship between DES and TP or BTP was studied by molecular simulation. • The interaction types and site distribution of extractive desulphurization were revealed at the atomic level. The improvement of fuel quality requires the reduction of sulfur content. The main challenge of catalytic cracking diesel extraction desulfurization is to find low-price and good-performance extractants. Based on experimental research, this work further explores the separation mechanism of DES for thiophene (TP) and benzothiophene (BTP). First, the COSMOS-RS model was used to predict the separation performance of 10 HBAs and 10 HBDs for TP and BTP. The results showed that the low-cost carboxylic acid based DES had excellent separation performance. Secondly, the effect of experimental conditions on the separation performance of three carboxylic acid based DESs was investigated. When the molar ratio of DES to TP and BTP was 3:1, after three stage extraction, the extraction rates of TP and BTP by TEAC: PrA(1:3) were 98.06 % and 98.53 %, respectively. Finally, the structure–activity relationship was studied by using quantum chemistry and molecular dynamics simulation. It was found that E vdW plays a dominant role in the desulfurization process and does not include H-bond interactions. TEA+ was distributed parallel to the aromatic ring and has a CH···π interaction with thiophene. TP and BTP were distributed in the voids of DES and do not affect the regeneration performance of DES. [ABSTRACT FROM AUTHOR]

• The first time to explore the effect of ILs and DESs in separating diisopropyl ether-ethanol azeotrope system. • Combined with molecular simulation, the mechanism of extraction and separation was clarified. • Designed the extraction and separation process of diisopropyl ether-ethanol-ILs for the first time. • For the extraction process, the impact on human health and the environment was evaluated using life cycle assessment. • Considering the high cost of ILs, recycling experiments are carried out. Ionic liquids (ILs) and deep eutectic solvents (DESs) were first proposed as green solvents to study and compare their azeotropic separation effects in diisopropyl ether (DIPE) and ethanol (EA). The COSMO-RS model was used to screen ILs/DESs, and the feasibility of the extractants were comprehensively analyzed in terms of viscosity, thermal stability, and toxicity. Experiments were carried out on selected ILs and DESs, and the results showed that the separation effect of ILs was significantly stronger than that of DESs. Quantum chemical calculations and molecular dynamics simulations were combined to comprehensively analyze and compare the microscopic mechanisms of extraction separation. Based on the experimental data, a DIPE-EA extraction-coupled separation process was designed. For the first time, life cycle analysis was used to comprehensively evaluate the impact of this process on human health and the environment from multiple perspectives, providing theoretical guidance for the separation of alcohol ethers in the industry. [ABSTRACT FROM AUTHOR]

[Display omitted] • Efficient extraction of S -heterocyclic aromatics with oxalic acid-based DES is proposed. • The COSMO-RS model were implemented to screen the appropriate DES. • The extraction mechanism was investigated by MD simulation and QC calculation. • The weak interaction was determined by the ESP and IGM analyses. The presence of thiophenes in fuel oil not only affects the quality of oil products, but also causes serious environmental problems. The efficient extraction of S -heterocyclic aromatics from fuel oil by π-electron donor-based (i.e., oxalic acid) deep eutectic solvents (DESs) is proposed for the first time. The distribution coefficient and separation factor of n-heptane + 2-methylthiophene/3-methylthiophene/thiophene in 100 DESs were predicted by COSMO-RS model, and the optimal DESs (i.e., Tetraethylammonium chloride-oxalic acid / Tetraethylammonium bromide-oxalic acid) was selected as the potential extractants. The selectivity and extraction capacity of the two DESs were measured and compared by liquid–liquid equilibrium experiments. The thermodynamic consistency of the experimental data was tested by Othmer-Tobias and Hand equations, which show that R 2 is>0.95, and the experimental results have high reliability. The interaction mechanism between the extractant and the target systems was analyzed by molecular dynamics simulation and quantum chemical calculation. The results of the mean square displacement and fraction free volume show that thiophene has higher displacement and diffusion in DES2 (i.e., tetraethylammonium bromide and oxalic acid) compared to 2-methylthiophene and 3-methylthiophene molecules. Moreover, the interaction analysis show that electrostatic energy is the main effect between molecules. Finally, the weak interaction between different molecular pairs was identified by the molecular surface electrostatic potential and the independent gradient model. This work provides insight into the design and screening of novel DESs for the extraction and separation of S -heterocyclic aromatics. [ABSTRACT FROM AUTHOR]

• π electron donor-based DESs were proposed to enhance the capture of BTEX. • The screening of 4 DESs out of 182 was used as absorbent for BTEX. • DESs still maintained good absorption effect after six adsorption–desorption cycles. • The electrostatic interaction is the main interaction between DESs and BTEX. • The absorption mechanism was revealed by QC calculations and MD simulations. π-electron donor-based deep eutectic solvents (DESs) were proposed to enhance the absorption of benzene, toluene, ethylbenzene, xylene (BTEX). The gas absorption performance of π-electron donor-based DESs for BTEX were systematically studied by computational thermodynamics combined with gas absorption experiments. COSMO-RS model was implemented to obtain the solvent capacity of BTEX in 182 DESs (i.e., 13 HBDs and 14 HBAs) to screen out potential excellent absorbents. In addition, the selected HBA, HBD and BTEX were analyzed by σ-profiles to preliminarily determine the interaction between molecules. The absorption properties of BTEX in DESs were measured. The results showed that the DES tetrabutylammonium bromide (TBAB) + benzoic acid (BA) (1:3) had the highest absorption capacity for BTEX in all DESs studied in this work (e.g. 0.911 g benzene/g at 298.15 K). Molecular dynamics simulations were performed to explore the diffusion behavior of gas in DESs. The free volume of DESs-gas blends gradually decreases with the increase of aromatics branched chains, and the mean square displacement shows the same trend. This indicates that aromatics without branched chains are easier to diffuse in DESs. Non-bond interaction analysis shows that electrostatic interaction and π-π interaction are the main interactions. In addition, the direct reason for the enhancement of BTEX absorption by π-electron donors is to enhance the X (O, C)-H···π interactions between DES and BTEX, and increase the additional π-π interaction with BTEX. [ABSTRACT FROM AUTHOR]

• The application of DESs in MTBE production is proposed for the first. • An extraction coupled distillation process based on DESs was developed. • The separation mechanism of DESs was elucidated at molecular scale. • DESs was determined by quantum chemistry and molecular dynamics simulation. Deep eutectic solvents (DESs) were first applied in the azeotrope separation process for the production of methyl tert -butyl ether (MTBE). Quantum chemistry and molecular dynamics simulations were used to explore the interaction mechanism of ChCl-based DESs in the liquid–liquid extraction of the MTBE–methanol (MeOH) system. The results showed that the extraction of MeOH by DESs mainly depended on the Van der Waals interactions between Cl atoms in ChCl and H atoms in the MeOH hydroxyl group. Hydrogen bond donors also enhanced the extraction effect to a certain extent. Liquid-liquid equilibrium experiments were carried out for the three selected DESs, and the ideal separation effect was obtained. The complete separation process of the MTBE-MeOH system was developed based on experimental data. This work demonstrates the application of DESs in the MTBE-MEOH system and provides guidance for the selecting and analysis of other DES extractants for the separation of low-carbon alcohol systems. [ABSTRACT FROM AUTHOR]