8 results on '"Wang, Jianji"'
Search Results
2. Insight into the cosolvent effect of cellulose dissolution in imidazolium-based ionic liquid systems.
- Author
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Zhao Y, Liu X, Wang J, and Zhang S
- Subjects
- Anions chemistry, Hydrogen Bonding, Molecular Dynamics Simulation, Quantum Theory, Solubility, Cellulose chemistry, Imidazoles chemistry, Ionic Liquids chemistry, Solvents chemistry
- Abstract
Recently, it has been reported that addition of a cosolvent significantly influences solubility of cellulose in ionic liquids (ILs), but little is known about the influence mechanism of the cosolvent on the molecular level. In this work, four kinds of typical molecular solvents (dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), CH₃OH, and H₂O) were used to investigate the effect of cosolvents on cellulose dissolution in [C₄mim][CH₃COO] by molecular dynamics simulations and quantum chemistry calculations. It was found that dissolution of cellulose in IL/cosolvent systems is mainly determined by the hydrogen bond interactions between [CH₃COO](-) anions and the hydroxyl protons of cellulose. The effect of cosolvents on the solubility of cellulose is indirectly achieved by influencing such hydrogen bond interactions. The strong preferential solvation of [CH₃COO](-) by the protic solvents (CH₃OH and H₂O) can compete with the cellulose-[CH₃COO](-) interaction in the dissolution process, resulting in decreased cellulose solubility. On the other hand, the aprotic solvents (DMSO and DMF) can partially break down the ionic association of [C₄mim][CH₃COO] by solvation of the cation and anion, but no preferential solvation was observed. The dissociated [CH₃COO](-) would readily interact with cellulose to improve the dissolution of cellulose. Furthermore, the effect of the aprotic solvent-to-IL molar ratio on the dissolution of cellulose in [C₄mim][CH₃COO]/DMSO systems was investigated, and a possible mechanism is proposed. These simulation results provide insight into how a cosolvent affects the dissolution of cellulose in ILs and may motivate further experimental studies in related fields.
- Published
- 2013
- Full Text
- View/download PDF
3. Aggregation of ionic liquids [C(n)mim]Br (n = 4, 6, 8, 10, 12) in D2O: a NMR study.
- Author
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Zhao Y, Gao S, Wang J, and Tang J
- Subjects
- Deuterium Oxide, Magnetic Resonance Spectroscopy, Motion, Solutions, Water, Imidazoles chemistry, Ionic Liquids chemistry
- Abstract
Aqueous solutions of five ionic liquids (ILs) of the 1-n-alkyl-3-methylimidazolium bromide family, [C(n)mim]Br (n = 4, 6, 8, 10, 12), were investigated by NMR measurements at 298.2 K as a function of IL concentrations. Critical aggregation concentrations and aggregation numbers of these ILs were determined by 1H NMR except for [C4mim]Br in D2O. The effects of the alkyl chain length of the cations were examined on the aggregation behavior of the ILs. 1H NMR data of the solvent D2O were used to investigate the hydration of the ILs in D2O, and it was found that the ionic hydration and the cation-anion association or aggregation of the ILs offset each other. The microenvironment of different protons of cations of the ILs in the aggregates was probed by determining the spin-lattice relaxation rate (1/T1). It is suggested that the imidazolium rings in the aggregates are exposed to water and that the molecular motion of the aggregates is more restricted than that of the monomers of the ILs. Furthermore, a stair-like microscopic aggregation structure is suggested for the [C(n)mim]Br/D2O (n = 6, 8, 10) systems from 2-D 1H-1H NOESY measurements.
- Published
- 2008
- Full Text
- View/download PDF
4. Apparent Molar Volumesand Expansivities of IonicLiquids [Cnmim]Br (n=4, 8, 10, 12) in Dimethyl Sulfoxide.
- Author
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Wang, Huiyong, Wang, Jianji, and Zhang, Shibiao
- Subjects
- *
MOLECULAR volume , *IONIC liquids , *DIMETHYL sulfoxide , *SOLUTION (Chemistry) , *TEMPERATURE effect , *ATMOSPHERIC pressure , *DILUTION - Abstract
Densities for solutions of [Cnmim]Br(n= 4, 8, 10, 12) ionic liquids (ILs) in dimethylsulfoxide (DMSO) have been determined as a function of ionic liquidconcentration at the temperature T= (293.15, 298.15,303.15, 308.15, and 313.5) K and atmospheric pressure. The apparentmolar volumes, apparent molar volumes at infinite dilution, and limitingapparent molar expansivities of the ILs have been obtained from theexperimental density data. These data were used to understand theeffect of the alkyl chain length of the ILs and experimental temperatureon the IL–DMSO interactions occurring in the studied solutions.It was shown that the apparent molar volumes at infinite dilutionincreased with increasing alkyl chain length of the ILs and temperatureof the systems. Furthermore, the values of the limiting apparent molarexpansibilities were found to be positive and decreasewith increasing temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
5. Effect of Alkyl ChainLength in Anions on Thermodynamicand Surface Properties of 1-Butyl-3-methylimidazolium CarboxylateIonic Liquids.
- Author
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Xu, Airong, Wang, Jianji, Zhang, Yajuan, and Chen, Qingtai
- Subjects
- *
IONIC liquids , *THERMODYNAMICS , *ANIONS , *IMIDAZOLES , *CARBOXYLATES , *CELLULOSE , *SURFACE chemistry , *LIGNINS , *TEMPERATURE effect - Abstract
Carboxylate-anion-based imidazolium ionic liquids (ILs)are powerfulsolvents for cellulose and lignin. However, little is known abouttheir fundamental physicochemical properties. In this work, 1-butyl-3-methylimidazoliumcarboxylate ILs 1-butyl-3-methylimidazolium formate ([C4mim][HCOO]), acetate ([C4mim][CH3COO]), propionate([C4mim][CH3CH2COO]), and butyrate([C4mim][CH3(CH2)2COO]),in which the alkyl chain length in the anions is being varied in contrastto the more usual studies where alkyl chain length in the cationsis varied, have been synthesized and their densities and surface tensionshave been determined experimentally at different temperatures. Byusing these data, the molar volume, isobaric expansivity, standardentropy, lattice energy, surface excess entropy, vaporization enthalpy,and Hildebrand solubility parameter have been estimated for theseILs. From the analysis of structureâproperty relationship,the effect of alkyl chain length in the anions on these physicochemicalproperties of the ILs has been assessed and the dissolution of celluloseand lignin in these ILs has been discussed. Such knowledge is expectedto be useful for understanding the nature of this class of solventfor the dissolution of biomacromolecules. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
6. Aggregation Behavior Modulation of 1-Dodecyl-3-methylimidazolium Bromide by Organic Solvents in Aqueous Solution.
- Author
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Wang, Jianji, Zhang, Lamei, Wang, Huiyong, and Wu, Changzeng
- Subjects
- *
CLUSTERING of particles , *ORGANIC solvents , *AQUEOUS solutions , *IMIDAZOLES , *IONIC liquids , *CHEMICAL sample preparation , *POLLUTION , *LIGHT scattering - Abstract
Material preparation in ionic liquids and environmental pollution control by ionic liquids are often closely dependent on the aggregation behavior of ionic liquids in solution. In the present work, conductivity, fluorescence probe, and dynamic light scattering techniques have been used to study the effect of organic solvents on the aggregation behavior of 1-dodecyl-3-methylimidazolium bromide in water. It was shown that the critical aggregation concentration (CAC), the ionization degree of the aggregates (α), and the standard Gibbs energy of aggregation (ΔGm°) of the ionic liquid increase, while its aggregation number (Nagg) and aggregates’ size decrease with increasing concentration of organic additives in water. These results have been discussed from the favorable interactions of alkyl chain of the ionic liquid with the mixed solvents. It is suggested that the solvophobic parameter, characterized quantitatively by Gibbs energy of transfer of hydrocarbon from gas into a given solvent, can be used to account for the effect of organic additives on the formation and growth of the ionic liquid aggregates in water. Aggregation behavior of ionic liquids in aqueous organic solutions can be modulated simply by the solvophobic parameters of hydrocarbon in the mixed solvents. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
7. Ionic-Liquid-Based CO2 Capture Systems: Structure, Interaction and Process.
- Author
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Zeng, Shaojuan, Zhang, Xiangping, Bai, Lu, Zhang, Xiaochun, Wang, Hui, Wang, Jianji, Bao, Di, Li, Mengdie, Liu, Xinyan, and Zhang, Suojiang
- Subjects
- *
IONIC liquids , *CARBON monoxide , *SOLUBILITY , *FUNCTIONAL groups , *ANIONS - Abstract
The inherent structure tunability, good affinity with CO2, and nonvolatility of ionic liquids (ILs) drive their exploration and exploitation in CO2 separation field, and has attracted remarkable interest from both industries and academia. The aim of this Review is to give a detailed overview on the recent advances on IL-based materials, including pure ILs, IL-based solvents, and IL-based membranes for CO2 capture and separation from the viewpoint of molecule to engineering. The effects of anions, cations and functional groups on CO2 solubility and selectivity of ILs, as well as the studies on degradability of ILs are reviewed, and the recent developments on functionalized ILs, IL-based solvents, and IL-based membranes are also discussed. CO2 separation mechanism with IL-based solvents and IL-based membranes are explained by combining molecular simulation and experimental characterization. Taking into consideration of the applications and industrialization, the recent achievements and developments on the transport properties of IL fluids and the process design of IL-based processes are highlighted. Finally, the future research challenges and perspectives of the commercialization of CO2 capture and separation with IL-based materials are posed. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
8. Effect of Substituent Groups in Anions on Some Physicochemical Properties of 1-Butyl-3-methylimidazolium Carboxylate Ionic Liquids.
- Author
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Xu, Airong, Zhang, Yajuan, Li, Zhiyong, and Wang, Jianji
- Subjects
- *
SUBSTITUENTS (Chemistry) , *ANIONS , *CARBOXYLATES , *IONIC liquids , *THERMODYNAMICS , *ETHYLENE glycol , *VAPORIZATION - Abstract
Inthis work, four 1-butyl-3-methylimidazolium carboxylate ionicliquids (ILs) with different substituent groups in anions, including1-butyl-3-methylimidazolium glycollate [C4mim][HOCH2COO], 1-butyl-3-methylimidazolium lactate [C4mim][CH3CHOHCOO], 1-butyl-3-methylimidazolium benzoate [C4mim][C6H5COO], and 1-butyl-3-methylimidazoliumglycinate [C4mim][H2NCH2COO], havebeen synthesized and characterized. Their densities (ρ) andsurface tensions (γ) have been determined experimentally inthe temperature range of (298.15 to 343.15) K. By using thermodynamicand empirical equations, molar volume (Vm), isobaric expansivity (αp), standardentropy (S°), lattice energy (UPOT), surface excess entropy (Ss), vaporization enthalpy (ΔlgHm0) and Hildebrand solubility parameter(δH) of these ILs have been derived from densityand surface tension data. The effects of substituent groups in carboxylateanions on densities and surface tensions of these ILs have been assessedfrom the analysis of the structure–property relationship. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
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