科创中国

In this study, we proposed a strategy that combines the fragment contribution corresponding states (FCCS) and free volume theory (FVT) method, namely FCCS-FVT, to calculate the viscosities of ionic liquids (ILs) covering a wide range of temperatures and pressures. In the method, the FCCS model was used to calculate the critical properties and densities of ILs, and then based on those values, the FVT model was applied to calculate the viscosities of ILs. The results indicated that the FCCS-FVT method shows high accuracy with 6.6% in average absolute relative deviation of total 2138 data points (25 ILs), which covers a wide range of temperatures (258.15-573 K) and pressures (0.06-300 MPa). Moreover, it is more convenient for the FCCS-FVT method to be applied for quick and accurate calculation of viscosities of ILs because it needs only three adjustable parameters.

Wenhui Tu;Shaojuan Zeng;Xiaochun Zhang;Xuezhong He;Lei Liu;锁江 张;Xiangping Zhang

Industrial & Engineering Chemistry Research

2019-4-10

In this work, the all-atom (AA) force fields were set up for three kinds of dual amino-functionalized imidazolium-based ionic liquids (ILs), composed by cations with different alkyl chain length and amino acid anion [Gly]^-. The force field was based on our previous work and the default parameters were developed in this study. Molecular dynamics simulations were performed. Validation was carried out by comparing simulation densities with experimental data, and good agreement was obtained. Molar volume and heat capacity at constant pressure were predicted. Mean square displacements for these ILs were computed and these ILs were proved to move very slowly. It may be caused by hydrogen-bonded network between ions and the terminal azyl. To depict the microscopic structures of the ILs, many types of radial distribution functions were investigated. It is interesting to find that not only the cation and anion, but also the anions themselves will form hydrogen bonds.

Xiaomin Liu;Guohui Zhou;锁江 张;Xiaoqian Yao

Fluid Phase Equilibria

2009-10-15

To obtain O-acylated chitin from shrimp shells directly, the used solvent should have multiple functions to remove calcium carbonate, protein, and acylated chitin. Herein, we use the acidic natural deep eutectic solvents (NADESs) with the ability to release H⁺ and various hydrogen bonding sites to achieve the above goal. The involved NADESs with three abilities of decalcification, deproteinization and acylation replaced acids, alkalis, catalysts, and acylation reagents in the conventional method. The experimental results revealed that the components of the NADESs, experiment temperature and time played key roles in the purity and degree of substitution (DS) of O-acylated chitin. Meanwhile, the ratio of shrimp shells to NADESs and a small amount of water had little effect on the preparation of O-acylated chitin. With the optimal NADES (choline chloride/dl-malic acid 1:2, ChCl 1-dl Mal 2) treatment under the optimal conditions, the purity of O-malate chitin reached 98.6% with a DS of 0.46, exhibiting antibacterial and anti-tumor effects. The experimental results showed that the removal of calcium carbonate and protein and acylation of chitin were carried out simultaneously. Mechanistic exploration using spectroscopy and experiments confirmed that H⁺ release from ChCl 1-dl Mal 2 was the main reason for the removal of calcium carbonate and initiation acylation reaction. The protein was degraded to amino acids because of the acidity of ChCl 1-dl Mal 2 and dissolved in the NADES due to hydrogen bonding formation with ChCl 1-dl Mal 2.

Mi Feng;兴梅 吕;Jie Zhang;Yi Li;Chunyan Shi;Lingling Lu;锁江 张

Green Chemistry

2019

Lithium-sulfur flow batteries show great superiority in large-scale energy storage. However, the sulfur utilization in high sulfur loading suspension catholyte declines sharply due to the insulating nature of sulfur/sulfides. Adding more carbon conductive materials can augment sulfur utilization, while high carbon content limits the specific energy and meanwhile increases the viscosity of suspension catholyte. In this work, a high-energy, low-temperature sulfur suspension catholyte is designed and prepared based on polyvinylpyrrolidone (PVP) functionalized Sulfur-Ketjenblack-Graphene composite (S-KB-G@P). Amphiphilic PVP is anchored onto the surface of graphene to enhance contact between polar sulfur species and conductive network constructed by nonpolar graphene and KB, and then facilitate the redox reaction of sulfur catholyte. Meanwhile, anchored PVP endows S-KB-G nanoparticles with well-dispersed characteristics, which reduces the viscosity and accelerates the ion transfer in highly concentrated S-KB-G@P suspension. The S-KB-G@P suspension catholyte exhibits high sulfur utilization of 89.5% and volumetric energy of 718 W h L⁻¹; moreover, high energy density of 445 W h L⁻¹ and excellent cycle stability are achieved at −30 °C. Verified in a laboratory flow cell, the strategy offers a new opportunity to develop high-energy flow batteries by amphiphilic functionalization in cold-climate region.

S. Xu;L. Zhang;H. Zhang;明灯 魏;X. Guo;锁江 张

Materials Today Energy

2020-12

A series of 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU) based bifunctional protic ionic liquids (DBPILs) were easily prepared by acid-base reactions at room temperature. They were used to catalyze the cycloaddition reaction of CO₂ with epoxides under mild conditions. As a metal free catalyst, the best DBPIL showed a 92% yield of products within 6 hours at 30 °C and 1 bar CO₂ without any solvents and co-catalysts. It could afford carbonates in good yields with broad epoxide substrate scope and CO₂ from simulated flue gas (15% CO₂/85% N₂). IR spectroscopy and DFT studies were carried out to investigate the mechanism of the cycloaddition reaction. The results showed that the DBPILs could activate both CO₂ and epoxides by alkoxy anions and powerful hydrogen-bonding, which was well consistent with experiments.

Xianglei Meng;Zhaoyang Ju;锁江 张;Xiaodong Liang;Nicolas Von Solms;Xiaochun Zhang;Xiangping Zhang

Green Chemistry

2019

A cobalt and iodide co-catalyzed oxidative amidation reaction between alcohols or aldehydes and amines has been developed. The reactions proceeded smoothly under mild conditions using tert-butyl hydroperoxide solution in water as the terminal oxidant, with broad functional group tolerance. Mechanistic studies indicated that the tBuO/tBuOO radical generated insitu is the active species responsible for hydrogen abstraction in this catalytic process, and not IO^-/IO₂ ^-/IO₃ ^- ions. Investigation into the reaction mechanism also revealed the potential transiency of a hemiaminal and the important role of its regeneration by imine hydration. A good hyd-ing: A protocol for Co^II/I^-/tert-butyl hydroperoxide-catalyzed oxidative cross-coupling of alcohols or aldehydes with amines has been developed. tBuO/tBuOO rather than IO^-/IO₂ ^-/IO₃ ^- is the active hydrogen-abstraction species in this catalytic process. Investigation into the reaction mechanism also revealed the potential transiency of a hemiaminal and the important role of its regeneration by imine hydration.

Ya Fei Guo;Tian Lu Ren;Bao Hua Xu;Yao Feng Wang;锁江 张

Asian Journal of Organic Chemistry

2016-4-1

A novel dual amino-functionalized ionic liquid, 1, 3-di (2′-aminoethyl)-2-methylimidazolium bromide (DAIL), was synthesized and investigated as a potential absorbent for CO₂ capture. CO₂ absorption behavior on pressure, temperature and concentrations of DAIL in aqueous solution were studied, and the absorption mechanism was investigated by spectroscopic methods and DFT calculations. The CO₂ capture capacity of 18.5 wt % and good thermal stability (T_d = 521.6 K) make DAIL a good candidate for industrial applications for CO₂ capture.

Jinzhi Zhang;Cai Jia;Haifeng Dong;Jinquan Wang;香平 张;锁江 张

Industrial & Engineering Chemistry Research

2013-5-1

A new approach is proposed by introducing mixture-type groups to the modified universal functional activity coefficient (UNIFAC, Dortmund) model for prediction of infinite dilution activity coefficients in highly nonideal aqueous solutions. The mixture-type group means a hypothetical one that appears in a particular type of mixtures only, and is considered here to account for hydrophobic effects specially taking place in a type of systems including water. Compared with the analytical solution of group (ASOG) model, the various UNIFAC models, and the correlation method of Pierotti, Deal and Derr (PDD), the new method has shown good accuracy. In addition, the new method can also improve considerably the predictive accuracy of mutual solubility, especially for systems with very small distribution ratios, in such cases the present group contribution models with common interaction parameters perform unsatisfactorily.

锁江 张;Toshihiko Hiaki;Kazuo Kojima

Fluid Phase Equilibria

1998-8

The alkylation of iso-butane with 1-butene was catalyzed by triflic acid (TFOH) coupled with a series of protic ammonium-based ionic liquids (AMILs), and the addition of the AMILs dramatically enhanced the efficiency of TFOH for the alkylation reaction. Up to 85.1% trimethylpentanes (TMP) selectivity and 98 research octane number (RON) were achieved with the optimized TFOH/AMIL catalyst (75 vol.% triflic acid and 25 vol.% triethylammonium hydrogen sulfate), which were much better than that with the commercial H₂SO₄ catalyst (65% TMP selectivity, 97 RON) and pure triflic acid. The addition of AMILs increased the I/O ratio dissolved in the catalyst system and adjusted the acidity of the TFOH/AMILs catalyst system, which were highly beneficial to the alkylation reaction and resulted in high TMP selectivity and high RON.

Peng Cui;Guoying Zhao;Hailing Ren;Jun Huang;锁江 张

Catalysis Today

2013-2-1

In recent years, a variety of ionic liquids (ILs) were found to be capable of dissolving cellulose and mechanistic studies were also reported. However, there is still a lack of detailed information at the molecular level. Here, long time molecular dynamics simulations of cellulose bunch in 1-ethyl-3-methylimidazolium acetate (EmimAc), 1-ethyl-3-methylimidazolium chloride (EmimCl), 1-butyl-3-methylimidazolium chloride (BmimCl) and water were performed to analyze the inherent interaction and dissolving mechanism. Complete dissolution of the cellulose bunch was observed in EmimAc, while little change took place in EmimCl and BmimCl, and nothing significant happened in water. The deconstruction of the hydrogen bond (H-bond) network in cellulose was found and analyzed quantitatively. The synergistic effect of cations and anions was revealed by analyzing the whole dissolving process. Initially, cations bind to the side face of the cellulose bunch and anions insert into the cellulose strands to form H-bonds with hydroxyl groups. Then cations start to intercalate into cellulose chains due to their strong electrostatic interaction with the entered anions. The H-bonds formed by Cl^- cannot effectively separate the cellulose chain and that is the reason why EmimCl and BmimCl dissolve cellulose more slowly. These findings deepen people's understanding on how ILs dissolve cellulose and would be helpful for designing new efficient ILs to dissolve cellulose.

Yao Li;Xiaomin Liu;锁江 张;Yingying Yao;Xiaoqian Yao;Junli Xu;兴梅 吕

Physical Chemistry Chemical Physics

2015-7-21