JOURNAL OF MOLECULAR LIQUIDS
·
2023
·
IF 6
Haocheng Wang,Yi Li,Songwei Zhang,Qinglun Che,Litian Hu,Jianjun Zhang
Although carbon dots (CDs) have attracted much attention due to their excellent lubricity and high load-carrying capacity as lubricant additives, the deficiency of easy agglomeration and the feature of solid state still restrict the application of CDs in the field of lubrication engineering. In order to break through the above limitations, novel liquid CD materials, carbon dot-based ionic liquids (CDILs), were synthesized via ionic modification of CDs with organic ammonium cations endowing new functions as novel liquid lubricants, which demonstrates that CDILs provide better lubrication performance than classical ILs ([BMIM][BF 4 ]) and at room and high temperature (30 °C and 100 °C). More importantly, the newly synthesized [N888H][CDs] containing tertiary ammonium cations with long alkyl chains exhibits the best lubrication performance. The resultant analyses give direct evidence that CD anions play a surprising role in improving the lubricity and protecting the steel/steel friction pairs, growing robust tribofilm with abundant CDs on the worn surfaces. Hence, it can not only offer fundamental insights into the formation of the tribofilm, but also provide a method for modifying CDs to promote their lubricity as liquid lubricants.
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ACS Nano
·
2022
·
IF 18.027
Yumiao Lu,Yanlei Wang,Feng Huo,Wei Chen,Ming Ma,Wei-Lu Ding,Hongyan He,Suojiang Zhang
Ultralow friction between interacting surfaces in relative motion is of vital importance in many pure and applied sciences. We found that surfaces bearing ordered monolayer ionic liquids (ILs) can have friction coefficient μ values as low as 0.001 at pressures up to 78 MPa and exhibit good structure recoverability. This extreme lubrication is attributed primarily to the ordered striped structure driven by the “atomic-locking” effect between carbon atoms on the alkyl chain of ILs and graphite. The longer alkyl chain has lower μ values, and the stripe periodicity is decisive in reducing energy dissipation during the sliding process. In combination with simulation, the alternate atomic-scale ordered and disordered ionic regions were recognized, whose ratio fundamentally determines the μ values and lubrication mechanism. This finding is an important step toward the practical utilization of ILs with negligible vapor pressure as superlubricating materials in future technological applications operating under extreme conditions.
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ACS Applied Polymer Materials
·
2022
·
IF 4.855
Yanyan Xie,Hongshuai Gao,Puyu Zhang,Congwen Qin,Yi Nie,Xue Liu
Biodegradable films prepared from cellulose have been developed in recent years. In this work, six kinds of wood cellulose films (WCFs) were successfully prepared using wood cellulose as raw materials and six ionic liquids (ILs) as solvents. The structure and properties of WCFs produced using six imidazole-based and 1,5-diazabicyclo[4.3.o]non-5-ene (DBN)-based ILs were investigated systematically. It indicated that the WCFs produced from 1-ethyl-3-methylimidazolium diethyl phosphate ([Emim]DEP) had a maximum transmittance of 90.1% and tensile strength of 124.5 MPa, which were much higher than the counterparts to 26.2% and 42.0 MPa of the WCFs produced using DBN-based ILs. Moreover, the structure and properties of WCFs and ILs had a little change after five recycles. Based on that, we used the screened [Emim]DEP as a solvent to prepare a highly efficient ultraviolet (UV)-to-red light conversion cellulose film (LCF) by doping rare-earth light-converting particles, CaAlSiN3:Eu2+ (CASN). Results showed that the LCF emitted red light at 640 nm and had excellent light conversion ability, which was conducive to photosynthesis.
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Applied Materials Today
·
2022
·
IF 8.663
Mengyang Dong,Kuiyuan Zhang,Xinyi Wan,Zhou Fang,Yue Hu,Zhizhen Ye,Yuqi Wang,Zhen Li,Xinsheng Peng
As a sustainable and environmental-friendly solvent with broad solubility, ionic liquids (ILs) have been utilized as a common medium to dissolve small molecules for industrial and biological applications The performance of these applications is inevitably affected by the transport behaviors of small molecules in ILs Here we present a promising method to acquire significantly accelerated transport of small molecules in ILs by confining ILs in two-dimensional nanochannels. The diffusion behavior of the chosen indicator, ferrocene, was enhanced by up to 40-fold in graphene oxide composed nanochannels compared with bulk systems. Modeling suggests the elevated molecular transport in ILs ascribes to the highly-ordered distribution and depressed interplay of nanoconfined ILs. This phenomenon offers a promising platform to manufacture novel devices of ultrafast molecular transport.
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Green Energy & Environment
·
2020
·
IF 6.395
Jiaqi Wu,Lei Zhang,Jinxing Long,Qiang Zeng,Biaolin Yin,Xuehui Li
Ionic liquids (ILs) have attracted increasing attention since last few decades due to their high molecular design abilities and wide applications in different fields. In this study, four novel fluorescent isoquinolino [2,1-a]quinoxalin-5-ium ILs were designed and synthesized via a two-step process including a simple dual Schiff's base formation and a subsequent [RhCp∗Cl 2 ] 2 -catalyzed oxidative C–H activation/annulation reaction. The as-synthesized ILs were extensively characterized using FT-IR, 1 H-NMR, 13 C-NMR, 19 F-NMR, HSQC-NMR, HMBC-NMR and HR-MS. Their photophysical properties were determined by steady-state fluorescence spectroscopy. The results demonstrate that all these ILs showed dual or triple emissions, large stokes shift (90 nm) and mechanochromic behaviors. Basing on solvatochromism and titration experiments, it is thought that the emission bands of the ILs are raised from their local excited states, charge transfer states or excited state proton transfer of cations, while the substitute effect of these quinoxaline derived ILs on their stokes shifts is negligible.
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JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Ting Huang,Wen Zhao,Xiaohua Zhang,Xuliang Nie,Jing Chen,Wanming Xiong
The hexafluorophosphate type ionic liquids , as one kind of functionalized ionic liquids, have a good application prospect in many fields. In this work, a series of diimidazole hexafluorophosphate ionic liquids with different carbon chain lengths (CnDIMF, n = 1, 2, 3, 4, 5, 6) were synthesized and characterized, so as to find the influence of cation on their structure and properties. The results showed that these products are needlelike or lamellar crystals , and their solubility and thermal stability were similar, but there are significantly different in their melting points and crystal structures. They were insoluble in non-polar or weak polar solvents , while have good solubility in polar aprotic solvents . Surprisingly, they could exhibit the temperature-controlled characteristics in methanol and water. These products have a good thermal stability up to 300 °C, and their decomposition temperature also slightly increases from 360 to 395 °C with the increase in the spacer chain length. The melting points of them are above 120 °C, which increased with the decrease of molecular weight if they belong to the same crystal system. Crystallography data showed that two cationic 1-vinylimidazolium were bound to the both sides of alkyl group , and the two imidazole rings were crystallographically dependant plane, and their structure changed from a semi-capsule with a close angle to a linear with a wide angle between the two imidazole rings. The study and determination of these properties, especially the temperature-controlled performance, is interesting and can afford reliable reference for future applications.
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JOURNAL OF MOLECULAR LIQUIDS
·
2021
·
IF 6.165
Yuqing Fei,Zhengjian Chen,Jiliang Zhang,Mingyuan Yu,Jing Kong,Zhisheng Wu,Jun Cao,Jiaheng Zhang
Thiazolium salts are structurally analogous to the most common imidazolium-based ionic liquids (ILs), and are supposed to be a new class of ILs. However, there are up to now only a few reports and absence of systematic study on thiazolium ILs. In this work, several thiazolium-based ILs were prepared, characterized and comparatively studied. Most of the thiazolium ILs are liquid at room temperature, with melting points below 43.0 °C. Good thermal stability was observed for thiazolium ILs, resulting in thermal decomposition temperatures up to 264 ∼ 358 °C. In comparison with the conventional imidazolium ILs, thiazolium ILs exhibit moderate density, refractive index and surface tension, which all generally decrease with temperature. According to the temperature-dependent viscosity and conductivity, thiazolium ILs follow fractional Walden’s rule, indicating strong ion-ion coupling. Besides, thiazolium ILs display relatively narrow electrochemical window (3.1 ∼ 4.0 V).
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JOURNAL OF MOLECULAR LIQUIDS
·
2019
·
IF 4.561
Yu Sun,Mengyi Qing,Luxin Chen,Jun Liu,Fei Zhong,Ping Jiang,Guowei Wang,Linghua Zhuang
Two Brönsted acidic ionic liquids (1-methy-3-(3-sulfopropyl) imidazolium acetate, as mPSAc, and 1-butyl-3-(3-sulfopropyl) imidazolium acetate, as bPSAc) were synthesized for chitosan dissolution. Physical properties, including density, pH value, viscosity, Hammett acidity (H 0 ), and Kamlet-Taft parameters (β and π*) of Brönsted acidic ionic liquids (BAILs), were studied and analyzed. The dissolution performance and regeneration properties of chitosan in BAILs were studied and compared with other ordinary ionic liquids ([Emim]Cl, [Bmim]Cl, [Amim]Cl, [Emim]Ac, [Bmim]Ac, [Amim]Ac). 1% chitosan was dissolved in two BAIL aqueous solutions (5% w /w) at 30 °C (35 min and 37 min, respectively). The regenerated chitosan was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). Molecular weight and deacetylation degree results showed that mPSAc endowed slight hydrolysis upon chitosan, only dissolution of chitosan at lower temperature. Density functional theory (DFT) simulations were performed to study the interactions between sulfopropyl imidazolium acidic ionic liquids and chitobiose. Four types of hydrogen bonds (C-H…O, O-H…O, N-H…S, N-H…O) and many strong hydrogen bonds were found in BAIL-chitobiose, suggesting strong interactions between BAILs and chitobiose. DFT simulation results indicated that the active hydrogen atom of imidazole ring, sulfonate ion and acetate ion played important roles in the chitosan dissolution process by the disruption of native hydrogen bonds of chitobiose.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2019
·Vol. 411
·期 19
·4929-4935
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IF 3.286
Cheng Kai,Wu Qiong,Jiang Ling,Liu Maili,Li Conggang
Ionic liquids have been extensively used as environmentally friendly solvents for enzymatic reactions and other biological systems. Understanding the mechanism of how ionic liquids affect protein stability is crucial for the biological reaction processes and protein storage using ionic liquids as solvents. Although effects of ionic liquids on protein stability have been studied, equilibrium thermodynamics of protein stability in ionic liquids has not been quantitatively measured. Herein, we utilized 19 F NMR to measure the equilibrium thermodynamics of protein stability in ionic liquid [C 4 -mim]Br. Our results show that proteins are significantly destabilized in [C 4 -mim]Br ionic liquids. Our results suggest that 19 F NMR provides a simple and effective way to study the thermodynamics of protein stability in ionic liquids. 19 F NMR will be applicable to facilitate the protein–protein interaction study in ionic liquids.
Graphical abstract
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ENERGY & FUELS
·
2018
·
IF 3.024
Zhongqi Ren,Lu Wei,Zhiyong Zhou,Fan Zhang,Wei Liu
Deep desulfurization of fuels has attracted worldwide attention as a result of environmental concerns. In this study, a new series of protic ionic liquids (PILs) with different acidic anions were synthesized and the extraction desulfurization of dibenzothiophene (DBT), benzothiophene (BT), and 4,6-dimethyldibenzothiophene (DMDBT) in model oil was carried out. The result showed that the extraction efficiency of DBT decreased in the order of [1,8-diazabicyclo[5.4.0]undec-7-ene] ([DBU]) > [N-formylmorpholine] ([NFM]) > [N-methylimidazole] ([HMIM]) > [N-methylmorpholine] ([NMM]) while the PIL anion was formate and DBU-based PILs with different anions could remove more than 80% DBT and BT in 1 cycle. The extraction efficiencies of [DBU]Pr were 98.33% for DBT (from 500 to 8.35 ppm) and 98.67% for BT (from 500 to 6.65 ppm) after 3 extraction cycles. The value for DMDBT was 99.38% (from 500 to 3.10 ppm) after 5 cycles. The interaction energies of these PILs with three aromatic sulfur compounds were also studied through quantum chemistry calculation. Finally, the regeneration of the used PIL was performed by the back-extraction method and checked by 1H nuclear magnetic resonance.
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ENERGY & FUELS
·
2019
·
IF 3.021
Jingjing Li,Xiao-Jie Lei,Xiao-Dong Tang,Xiao-Pu Zhang,Zhi-Yu Wang,Shuang Jiao
A series of imidazole- and pyridine-based dicationic ionic liquids (DILs) were synthesized and employed in extractive desulfurization (EDS) for the removal of sulfur compounds from commercial fluid catalytic cracking (FCC) gasoline. The influence parameters in the EDS process and regeneration of DILs are discussed. Under optimum operating conditions, the desulfurization efficiency can reach 79.72%. After five cycles, the sulfur content was reduced to less than 10 μg/g, and deep desulfurization was realized. The regeneration of the used DILs was performed by back-extraction, and the Fourier transform infrared and 1H nuclear magnetic resonance (NMR) spectra proved that the structure of DILs did not change. The relationship between acid strength and the desulfurization effect of DILs was studied by UV–vis spectroscopy. According to 1H NMR characterization, the main mechanism of the DILs' EDS process may be the interaction of π–π bonds. It is inferred from the chemical shift that the DILs have larger cation volume, which was conducive to increasing the aromatic π-electron density, producing stronger π–π interaction between the cations and aromatic sulfides, and thus having better EDS effect than ILs with mono-cationic. Finally, the adaptability of DILs was studied, and DILs have excellent desulfurization adaptability for different FCC gasolines.
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FUEL
·
2015
·
IF 3.52
Xianxiang Liu,Qiong Xu,Junyi Liu,Dulin Yin,Shengpei Su,Hui Ding
An effective method was developed for the production of reducing sugars (RS) from the hydrolysis of cellulose over a magnetic acid catalyst. The sulfonation of the core–shell structured Fe 3 O 4 @C with Fe 3 O 4 as a magnetic core could generate the magnetic acid catalyst (Fe 3 O 4 @C-SO 3 H). The hydrolysis of cellulose was performed under several crucial conditions. Hydrolysis of cellulose in ionic liquid 1-butyl-3-methyl imidazolium chloride ([BMIM]Cl) was greatly affected by the content of water. The highest RS yield and glucose selectivity were obtained in 72.1% and 82.5% at 110 °C after 3 h with the weight ratio of [BMIM]Cl to water being 20. It should be mentioned that this catalyst not only owns the high stability but also can be facile recovered by an external magnet.
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危险品化学品经营许可证（带存储）