科创中国

Ionic liquids (ILs) offer a wide range of promising applications because of their much enhanced properties. However, further development of such materials depends on the fundamental understanding of their hierarchical structures and behaviors, which requires multiscale strategies to provide coupling among various length scales. In this review, we first introduce the structures and properties of these typical ILs. Then, we introduce the multiscale modeling methods that have been applied to the ILs, covering from molecular scale (QM/MM), to mesoscale (CG, DPD), to macroscale (CFD for unit scale and thermodynamics COSMO-RS model and environmental assessment GD method for process scale). In the following section, we discuss in some detail their applications to the four scales of ILs, including molecular scale structures, mesoscale aggregates and dynamics, and unit scale reactor design and process design and optimization of typical IL applications. Finally, we address the concluding remarks of multiscale strategies in the understanding and predictive capabilities of ILs. The present review aims to summarize the recent advances in the fundamental and application understanding of ILs.

Kun Dong;Xiaomin Liu;Haifeng Dong;Xiangping Zhang;锁江 张

Chemical Reviews

2017-5-24

In this study, a series of novel quasi-deep eutectic solvents (QDESs) based on organic base and thiourea (TU) and its derivatives were formed. Among them, DBU/TU or methylthiourea (MTU) could be used for the formation of the stable γ-Al₂O₃ colloid at quite a high concentration (0.6 mol %), which was verified by small-angle X-ray scattering (SAXS) experiments. The solution is highly fluidic with a viscosity of 46.2 mPa·s at 50 °C. The attenuated total reflection infrared spectra (ATR-IR), ²⁷Al nuclear magnetic resonance (NMR), and density functional theory (DFT) calculation proved that γ-Al₂O₃ was coordinated with the sulfur atom of methylthiourea. Electrodepositing of aluminum from the system at a low temperature (50 °C) and atmospheric environment was achieved. The cyclic voltammogram indicated a good aluminum deposition peak at -?0.26 V at 50 °C. SEM, EDS, and XRD pattern showed that homogeneous, pure, and adherent aluminum layers were obtained. Moreover, these DESs are versatile and can be used for dissolving other metals, metal sulfides, and metal oxides, including CoO, NiO, Ni₂O₃, MoO₃, CuS, Fe, W, Cu, and V₂VI₃ chalcogenides. Therefore, this work extended the scope of green solvent and made an improvement in both low temperature electrolytic alumina and solution processing of other metal-based materials.

Jinfang Wang;Peng Wang;Qian Wang;Hongyu Mou;Bobo Cao;Dongkun Yu;Debao Wang;锁江 张;Tiancheng Mu

ACS Sustainable Chemistry and Engineering

2018-11-5

The recovery of carboxylic acids from dilute aqueous solution is necessary but difficult in chemical industry. Methacrylic acid (MAA) is an important chemical widely used in polymer industry. In this work, the recovery of carboxylic acid from diluted aqueous solution by liquid-liquid extraction using ionic liquids (ILs) as extractants was studied. MAA was employed as model carboxylic acid. The partition coefficients of MAA in biphasic system and the extraction efficiencies of MAA were determined for imidazolium-based ILs and quaternary ammonium salt ILs with different structure of cation and anion. The extraction conditions such as extraction time, extraction temperature, mass ratio of ILs to MAA aqueous solution, initial concentrations of MAA, and water content were evaluated. An internal mechanism of the MAA extract by ILs was revealed by combining solvatochromic study, FT-IR and quantum chemical calculations. The results show that the strong hydrogen bond basicity (β) of ILs results in the high partition coefficient of MAA, which provides guidance to molecular design of ILs for the high efficient extractive separation of MAA from diluted aqueous solution. Based on this, IL with strong hydrogen bond basicity ([N₈₈₈₁]Cl) was used to extract MAA from dilute aqueous solution. Compared with hexane which is conventional solvent used in MAA extractive separation, [N₈₈₈₁]Cl can get 49 times higher of partition coefficient value and the extraction efficiency reach 94.57% for the single-stage extraction.

Yinge Bai;Ruiyi Yan;Feng Huo;Jianguo Qian;Xiangping Zhang;锁江 张

Separation and Purification Technology

2017

Ionic liquids have been regarded as a new and effective solvent and absorbent, however, the fluid dynamics of ionic liquids have not been thoroughly investigated. Computational fluid dynamics (CFD) is an increasingly important method to understand the fluid dynamics of multiphase fluid. In this work, the gas holdup, bubble size distribution and flow velocities of ionic liquid-air two-phase flow in bubble column were investigated by using Euler-Euler method and population balance model (PBM) coupled numerical model. Considering the special properties of ionic liquids, ionic liquid drag coefficient and Schiller-Naumann model were both used as interphase drag coefficient. The numerical simulation results showed that the general gas holdup and the uniformity of gas distribution both increased with increasing superficial gas velocity. The predicted general gas holdup with ionic liquid drag coefficient agreed with the experimental data better than that of Schiller-Naumann model. Ionic liquid drag coefficient overestimated the general gas holdup and the average error of simulation result with drag coefficient was 8.1%. Schiller-Naumann underestimated general gas holdup and the average error of simulation result with Schiller-Naumann model was 22.8%. The bubble size distribution was studied by using PBM model, discrete method was used to solve the population balance equations, and the bubbles in the column were divided into 10 groups ranging from 1 mm to 9.85 mm. The simulated bubble size distributions agreed with experimental results. The bubbles of low superficial gas velocity were larger than those of high superficial gas velocity, and the bubble size range of low gas velocity was wider than that of high gas velocity. This was caused by different bubble coalescence and breakup rates of different superficial gas velocities The study of bubble and liquid velocity distribution showed that the uniformity of liquid velocity in the column increased with increasing gas velocity.

Yan Xu;Haifeng Dong;Xiao Tian;香平 张;锁江 张

Huagong Xuebao/CIESC Journal

2011-10

Novel tetracarboxyl-functionalized 2,2′-biimidazolium-based ionic liquids (ILs) with different anions were synthesized in two steps from readily available and sustainable starting materials including ammonium acetate, glyoxal, and halogenated propionic acid. The functionalized IL exhibited higher catalytic activity towards the cycloaddition of CO₂ to terminal epoxides. With propylene oxide as a substrate, the optimum yield of propylene carbonate reached 82.7% at an initial CO₂ pressure of 2.0MPa for 4h at 140°C. Moreover, the functionalized IL catalyst displayed a high stability and can be reused for at least five cycles without obvious loss of catalytic activity. The results provide a simple and economical way to synthesize multi-functionalized imidazolium-based ILs with versatile potential applications.

Miaona Feng;Guoying Zhao;Hongling Gao;锁江 张

Australian Journal of Chemistry

2015

Sb-doped Mo-Bi-Fe-Co-Cs-Ce-K-O composite oxide catalyst was prepared by coprecipitation and was used in selective oxidation of isobutene to methacrolein (MAL). The effects of Sb dosage, GHSV, and volume ratio of isobutene to air on activity of catalyst were studied. The constituent of Sb-doped Mo-Bi-Fe-Co-Cs-Ce-K-O composite oxide catalysts were CoMoO₄ , Bi₂Mo₃O₁₂, FeMoO, and Bi₂Mo₂O₉. Doping of Sb to the catalyst led to distortion of Bi₂Mo₃O₁₂, which affected the catalytic performance and inhibited over-oxidation of product MAL, so higher MAL yield was achieved. The conversion of isobutylene, selectivity, and yield to MAL were 95.3, 71.7, and 68.3%, respectively.

Wei Tian;Hailang Zhang;Ruiyi Yan;Qian Wang;锁江 张

Petrochemical Technology

2008-11-15

As a novel class of green functional materials and benign solvents with unique properties, ionic liquids (ILs) have been attracted increasing attention. It is indispensable to understand the structure-property relationships of ILs from the viewpoints of multiscale. To bridge the electronic, atomistic/molecular and mesoscopic scales across several prders-of-magnitude in length and time, the molecular simulation are performed on the way. The multiscale structures of ILs have been studied and analyzed by using the computational chemistry. The approaches of quantum mechanics (QM), molecular dynamics (MD), computational fluid dynamics (CFD) and experimental measures have been performed to validate and support the quantitative structure-property relationships of ILs. On the above basis, the more and more applications of ionic liquids in process engineering, energy sources, environments and materials are expected.

锁江 张;Yao Xiaoqian;Liu Xiaomin;Wang Jinquan

Progress in Chemistry

2009-11

The photocatalytic hydrogen (H₂) generation by the high nuclearity Co substituted polyoxometalates (POMs), K₁₀Na ₁₂[{Co₃(B-β-SiW₉O₃₃(OH))(B- β-SiW₈O₂₉ (OH)₂)}₂] ·49H₂O (abbreviated as CoPOM) was reported. Owing to the multielectron redox capabilities of the high nuclearity CoPOM, the POM showed excellent photocatalytic activities toward H₂ evolution in both molecule scale (homogeneous) and composite (heterogeneous) systems. The photocatalytic activities of CoPOM were much better than H₃PW ₁₂O₄₀. UV-Vis-NIR absorption spectral, Raman spectral, cyclic voltammetric behavior and intermittent photoelectrochemical current response were used to characterize the structure of the TiO₂/CoPOM composite and interaction between TiO₂ and CoPOM. Analogous "Z-scheme" and "dye" sensitized mechanisms were proposed for the homogeneous and heterogeneous systems toward photocatalytic H₂ evolution under solar light irradiation, respectively.

Rongji Liu;Xinke Shang;Cuixia Li;Xiaolin Xing;Xuelian Yu;Guangjin Zhang;锁江 张;Hongbin Cao;Lihua Bi

International Journal of Hydrogen Energy

2013-8-12

In this work, the effect of SO₂ on the densities and viscosities during absorption processes of pyridinium-based ionic liquids (ILs), such as the conventional ILs [C₄Py][BF₄] and [C₄Py][SCN] and the tertiary amino-functionalized IL [NEt₂C₂Py][SCN], was investigated. The mechanism of the variations in these two physical properties was also explained in detail through a combination of experimental methods and simulation calculations. The results indicated that the densities of the conventional and functionalized ILs increased gradually with increasing amounts of SO₂. However, the viscosities of two kinds of ILs during SO₂ absorption showed different variation trends according to different mechanisms of SO₂ absorption, i.e., physical absorption and chemical absorption, which was proven by the in situ Fourier transform infrared results. The viscosity changes of the functionalized IL [NEt₂C₂Py][SCN] during SO₂ absorption experienced two stages. First, the viscosity increased sharply because of chemical interaction, forming a charge-transfer complex, and then decreased drastically because of the physical interaction between the anion and SO₂. However, there was a monotonous and sharp decline in the viscosity of the conventional ILs with an increase of the SO₂ capacity, which showed the same trend as that of [NEt₂C₂Py][SCN] in the SO₂ physical absorption stage. Furthermore, the ionic interaction and microstructures of the conventional ILs before and after SO₂ absorption were further studied by molecular dynamics simulation and quantum-chemical calculation. It was demonstrated that viscosity reduction may mainly originate from a decrease of the electrostatic interaction between the cation and anion of the ILs because of the presence of SO₂.

Shaojuan Zeng;Xiaochun Zhang;Hongshuai Gao;Hongyan He;香平 张;锁江 张

Industrial & Engineering Chemistry Research

2015-10-12

In bipropulsion systems, hypergolic ionic liquids with B-H groups, as promising alternatives to toxic hydrazine-based fuels, can improve propulsion performance. A series of borohydride cluster-based salts with excellent hydrolytic and thermal stabilities (T_d > 200 °C), and the highest density (1.18 g cm^-3) of any known borohydride hypergolic ionic liquids were prepared. Upon contact with white fuming nitric acid or N₂O₄, these new salts have ultra-fast ignition delay times (as low as 1 ms), which is a superior ignition performance. Theoretical studies were employed in order to understand their high stability and good ignition performance.

Nianming Jiao;Yanqiang Zhang;Long Liu;Jean'Ne M. Shreeve;锁江 张

Journal of Materials Chemistry A

2017