SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Pengfei Li,Dawei Shang,Wenhui Tu,Shaojuan Zeng,Yi Nie,Lu Bai,Haifeng Dong,Xiangping Zhang
Ammonia (NH 3 ) is one of the main reasons for the formation of aerosols. NH 3 pollution mainly comes from a large amount of emissions in industrial production. Ionic liquids (ILs), as a green solvent, can efficiently separate and recover NH 3 from industrial NH 3 -containing tail gas. In this work, novel protic ionic liquids (PILs) with hydrogen bond donating ability were designed and synthesized by incorporating six-membered N -heterocyclic compounds including pyridinium and piperidinium as cations. Three pyridinium-based PILs with single protic H showed higher NH 3 capacity with the maximum of 3.078 mol NH 3 /mol IL at 313.1 K and 0.10 MPa than the piperidinium-based PILs with double interaction sites. However, there was obvious reduction in NH 3 capacity for pyridinium-based PILs during absorption and absorption-desorption cycles. The reason is that the acidic protic H of cations of pyridinium-based PILs is easily stripped in supersaturated alkaline environment due to the smaller p K a of pyridine derivatives than that of NH 3 , forming the NH 4 + and volatile neutral pyridine derivatives. This work will provide useful guidance to the design of novel ILs used for efficient and reversible absorption of NH 3 .
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Journal of Environmental Chemical Engineering
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2021
·
IF 5.909
Qingxiang Liu,Tao Zhang,Peng Gao,Jun Gao,Dongmei Xu,Pingping Zhao,Lianzheng Zhang,Yinglong Wang
As a hopeful solvent, ionic liquids with tremendous combination of functional chemical sites in the cations and anions can make the separation process efficiently and selectively. Thus, to test the effect of the functional chemical sites in the cations and anions on extracting typical heterocyclic N -compound, indole was adopted as the representative compounds due to its high content and valuable application. In present work, NMP-based IL, [EtOHpyr][BuRA], with dual functional chemical sites was designed and employed to separate indole from diverse resources. The mechanism for the separation process was explored, the IL is evaluated to separate indole with the polarity analysis based on the COSMO-SAC model. Molecular dynamics simulation analysis contributed to understand the H-bonds interaction between indole and IL more indicative. The results demonstrated that the H-bonds between indole and dual functional chemical sites in [EtOHpyr][BuRA] served as the key driving force during the separation process. To validate the effect of functional chemical sites, [EtOHpyr][BF 4 ], [Etpyr][BuRA] and [Etpyr][BF 4 ] were also used for comparison. Furthermore, the influence of extraction of NMP-based ILs on indole, mass ratio (IL: model oil) and extraction temperature were investigated. Under the optimal conditions (25 ℃, mass ratio = 1:5), [EtOHpyr][BuRA] showed the best performance among those four ILs, which extraction efficiency can reach up to 95.15 wt%. The results agreed with the simulation results well. This work can provide an efficient designed ILs for the extraction of indole.
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EUROPEAN POLYMER JOURNAL
·
2021
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IF 4.598
Qiaohong Peng,Li Wei,Xiaoyan Zhang,Ying Wu,Khalid Mahmood,Zhengping Liu,Lisha Zhang
Ionic liquids (ILs), instead of the classical organic solvents, have shown great improvements in chemical processes. Herein, Water-insoluble alkyl- and benzyl-substituted imidazolium bis(trifluoromethanesulfonyl)imides as non-volatile and thermostable solvents were employed in the direct polycondensation of l -lactic acid (LLA). The effects of monomer concentration, reaction temperature and miscibility between the ILs and poly( l -lactic acid) (PLLA) were comprehensively investigated. Biodegradable PLLA with weight-average molecular weight as high as 132 kDa was synthesized. Compared to melt-polycondensation of LLA, far higher molecular weight could be achieved via the solution polycondensation of LLA in ILs since the viscosity of the polymer melt could be significantly reduced based on the dilution effect of ILs. Polycondensation kinetics of LLA in bulk and in an IL demonstrated that the IL could accelerate the polycondensation of LLA. Influence of lactide, the main by-product, on the polycondensations of LLA was also studied kinetically.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2021
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IF 3.171
Yipeng Zheng,Zhennan Cao,Zheng Zhou,Gaodong Yang,Zhibing Zhang
A series of SO 3 -functional Brønsted acidic ionic liquids (SBAILs) were prepared to catalyze the N -formylation of aniline with DMF . The reaction conditions such as ionic liquid type, reaction temperature, catalyst loading and molar ratio of reactants were investigated. To the best of our knowledge, kinetic model for the N -formylation of aniline with DMF using SBAIL was firstly built and simulated. The studies on the reaction order of the reaction were evaluated by initial concentration method, and the kinetic parameters such as reaction rate constant and activation energy were proposed and used to explain the catalytic activities of the SBAILs catalysts. Accordingly, the recycling experiments showed that the SBAIL [Bsmim][HSO 4 ] can be easily recovered and reused with stable activity. Further, the temperature-controlled study emphasized that the ionic liquid was easy to be separated and environmentally friendly.
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AICHE JOURNAL
·
2019
·Vol. 66
·期 1
·e16779
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IF 3.463
Guiling Shi,Hongqin Zhao,Kaihong Chen,Wenjun Lin,Haoran Li,Congmin Wang
For an ideal absorbent for CO 2 capture from flue gas, there are some key features including easy preparation, high stability, low absorption enthalpy, high capacity at high temperature and excellent reversibility. Herein, several polyamine-functionalized ionic liquids (ILs) were easily prepared from cheap polyamines and lithium salts, which exhibited significantly improved stability due to the presence of multisite coordinating interactions. The viscosity was reduced by introducing polyalcohol-based ILs, leading to polyamine-based hybrid ILs. Interestingly, these polyamine-based hybrid ILs exhibited high CO 2 capacity (4.09 mmol/g, 0.1 bar) at high temperature (80°C) and excellent reversibility in the presence of H 2 O and O 2 , which is superior to many other good absorbents. Moreover, these ILs also showed good performance for CO 2 capture from stimulated air (2.10 mmol/g, 380 ppm). We believe that this method with easy preparation, low cost, high efficiency and excellent reversibility has a great potential in the industrial capture of CO 2 from flue gas.
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Frontiers in Chemistry
·
2019
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IF 3.782
Cai Guangming,Yang Shaoqi,Zhou Qing,Liu Lifei,Lu Xingmei,Xu Junli,Zhang Suojiang
In order to obtain the regularities of physicochemical properties of hydroxy protic ionic liquids (PILs) and broaden their potential application, a series of 2-hydroxyethylammonium sulfonate-based PILs were synthesized through proton transfer reaction and characterized by NMR and FT-IR and elemental analysis. Their phase transfer behavior (Tm) and initial decomposition point (Td) were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. Meanwhile, the regularities of density (ρ), viscosity (η) and electrical conductivity (σ) of synthesized PILs at different temperatures were measured. The results indicated that their physicochemical properties were tightly related with their structures and the interactions between cations and anions. In addition, the dissociation constants (pKa) of synthesized PILs were obtained by acid-base titration, which revealed that all synthesized PILs had pKa exceeding 7 and their cations were the crux of determining the pKa value. Moreover, several synthesized PILs with a low melting temperature also showed potential application in the deoxidation reaction of cyclohexanol, as they had conversion rates approximating 100% and the selectivity of cyclohexane or cyclohexene was about 80%.
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PubMed
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Green Energy & Environment
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2019
·
IF 0
Zhiyong Li,Ruipeng Li,Xiaoqing Yuan,Yuanchao Pei,Yuling Zhao,Huiyong Wang,Jianji Wang
Phenolic compounds exist in crude oil as pollutants, and their removal is vital important for the refining and further application of oils. In traditional separation approaches, strong acid and strong base have to be used to remove these compounds, which may cause serious environmental problems. In this work, 19 kinds of cholinium ionic liquids have been developed to separate phenol from model oil by liquid–liquid extraction. Structural effect of anions of the ionic liquids in the separation is systematically investigated. It is found that depending on the chemical structure of ionic liquids, phenol can be removed from toluene with single-step removal efficiency from 86 to 99% under optimal conditions. The type of substituent groups and the -CH 2 number between two carboxylates have obvious effect on the removal efficiency, and more hydrophilic ionic liquids have a stronger extraction performance for phenol. Furthermore, thermodynamic, 13 C NMR, 1 H NMR and density functional theory calculations have been performed to characterize the extraction process and to understand the extraction mechanism. It is shown that the extraction of phenol from oil to ionic liquid is a favorable process, and this process is mainly driven by enthalpy change . The formation of the hydrogen bond between anion of the ionic liquid and -OH of phenol is the main driving force for the extraction of phenol from oil to the ionic liquids.
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AICHE JOURNAL
·
2019
·Vol. 65
·期 8
·e16606
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IF 3.463
Li Cui,Kun Jiang,Junfeng Wang,Kun Dong,Xiangping Zhang,Fangqin Cheng
The solvent extraction of Li + by Cyanex 923 was investigated upon the addition of different imidazolium-based ionic liquids (ILs). The results showed 1-hydroxylethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([HOEmim][NTf 2 ]) can improve the extraction of Li + most effectively. The fundamental mechanism is that [HOEmim][NTf 2 ] can remarkably enhance the coordination ability of Cyanex 923 to Li + to form more stable and hydrophobic ion-pair species [Li(Cyanex 923) n ][NTf 2 ] ( n max = 3) resulting from the electrostatic interaction and typical hydrogen bonding of IL, and thus facilitating the transfer of Li + into organic phase. This work has revealed the transfer mechanism of Li + in a solvent extraction system comprising of IL and neural ligand. The knowledge of the coordination environment of Li + in the presence of IL also gives us a new insight into the separation of 6 Li/ 7 Li. The disadvantage of this process is the loss of IL. However, this study provides guidance for the design of better IL-based systems for the separation of metal ions.
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JOURNAL OF CHROMATOGRAPHY A
·
2019
·
IF 3.858
Xiaofei Ma,Yingxiang Du,Xiaodong Sun,Jie Liu,Zhifeng Huang
In this study, three functionalized chiral ionic liquids (CILs) derived from l -valinol, l -prolinol and l -phenylalaninol, namely N,N,N- trimethyl- l -valinol-bis(trifluoromethanesulfon)imide ([TMLV] + [Tf 2 N] − , CIL1), N,N- dimethyl- l -prolinol-bis(trifluoromethanesulfon)imide ([DMLP] + [Tf 2 N] − , CIL2) and N,N,N- trimethyl- l -phenylalaninol-bis(trifluoromethanesulfon)imide ([TMLP] + [Tf 2 N] − , CIL3), were synthesized and subsequently utilized for enantiomeric separation in capillary electrophoresis (CE) with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) as chiral selector for the first time. Compared with traditional single HP-β-CD separation system, the synergistic system exhibited substantially improved separations of six tested drugs. Using the CIL1/HP-β-CD as a model system, the influence of crucial parameters including the type and proportion of organic modifier, CILs concentration, HP-β-CD concentration and buffer pH was investigated in detail. Additionally, molecular modeling with AutoDock was applied to elucidate the enhanced enantioselectivity in the presence of CILs, which has certain guiding value in predicting the migration order of the enantiomers and studying the interactions important for the chiral recognition.
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ACS Sustainable Chemistry & Engineering
·
2018
·
IF 6.14
Guiling Shi,Kaihong Chen,Yongtao Wang,Haoran Li,Congmin Wang
Ionic liquids can be designed by varying a great deal of anions and cations offering efficient CO2 capture or CO2 utilization. Generally, the anion played a key role, but the cation did not have a significant impact. Here, a strategy for rational design of functionalized ionic liquids for efficient synthesis of quinazoline-2,4(1H,3H)-diones from CO2 has been developed through tuning the cations of aprotic ionic liquids. The basicity of cation affects its catalytic activity dramatically and the hydrogen bond from cation can promote this reaction. Then, hydroxyl functionalized ionic liquid [Ch][Im] was designed, which exhibited the best catalytic activity in this reaction. Through the combination of quantum-chemical calculations, NMR spectroscopic investigations, and controlled experiments, the results indicate that in situ generated [Ch][Im]-CO2 complex is the real catalyst. Furthermore, aprotic IL [Ch][Im] exhibits good generality and reuseability. Remarkably, quinazoline-2,4(1H,3H)-dione can also be obtained under simulated flue gas system on a gram scale with excellent yield using [Ch][Im] as catalyst. As we know, this is the first time that obtains quinazoline-2,4(1H,3H)-dione in excellent yield under flue gas condition.
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RSC Advances
·
2018
·Vol. 8
·期 47
·26554-26562
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IF 2.936
Liying Guo,Lili Deng,Xianchao Jin,Yirong Wang,Haozhi Wang
In this study, functionalized composite catalysts, namely, ILs (ILX/(ZnBr2)2), with hydroxyl, carboxyl and amino groups immobilized on a molecular sieve (MCM-22) support were synthesized with the help of a silane coupling agent, 3-chloropropyltriethoxysilane (CPTES). Cycloaddition of CO2 and propylene oxide (PO) was carried out in a fixed bed reactor. The results show that MCM-22-CPTES-[AeMIM][Zn2Br5] demonstrates the best catalytic properties for this reaction. A high selectivity and yield of propylene carbonate (PC) could be reached at 130 °C under a CO2 pressure of 2.0 MPa, with a LHSV of 0.75 h−1 and a molar ratio of CO2/PO of 3 : 1. The yield stabilized at 61.6% after 50 h in the fixed bed reactor.
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AICHE JOURNAL
·
2019
·Vol. 65
·期 8
·e16625
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IF 3.463
Zhen Song,Xutao Hu,Yageng Zhou,Teng Zhou,Zhiwen Qi,Kai Sundmacher
Although double salt ionic liquids (DSILs) offer significant advantages over classical two-ion ionic liquids as separation solvents, relevant studies are still scarce and a systematic DSIL selection method is thus highly desirable. In this contribution, a rational method for designing DSILs as extraction solvents is proposed and exemplified by the thiophene/ n -octane separation. The effects of additional degrees of freedom for DSIL design (i.e., double cations and/or anions and the ion ratio) on the thermodynamic properties are first analyzed by COSMO-RS. Then, a multilevel DSIL design method combining the prediction of infinite dilution thermodynamic properties, the estimation of physical properties, the evaluation of phase equilibrium behavior, and the experimental validation is proposed. By applying this method, [C 2 MIm][OAc] x [NO 3 ] 1- x ( x = [0, 1]) and [C 2 MIm][OAc] x [SCN] 1- x ( x = [0.70, 1]) are identified as promising DSIL solvents for the thiophene/ n -octane separation. Correspondingly, the liquid–liquid equilibria of {DSILs + thiophene + n -octane} with the designed DSILs are experimentally studied.
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