284049-75-8Relevant academic research and scientific papers
Viscosities and conductivities of 1-butyl-3-methylimidazolium carboxylates ionic liquids at different temperatures
Xu, Airong,Zhang, Yajuan,Li, Zhiyong,Wang, Jianji
, p. 3102 - 3108 (2012)
In recent years, 1-butyl-3-methylimidazolium carboxylates ionic liquids (ILs) have been reported to be powerful solvents for the dissolution of cellulose and chitosan. However, very few studies have been conducted to investigate their basic physicochemical properties such as viscosity and conductivity. In this work, we have synthesized 1-butyl-3-methylimidazolium carboxylates ILs: 1-butyl-3-methylimidazolium formate ([C4mim][HCOO]) , 1-butyl-3-methylimidazolium acetate ([C4mim][CH3COO]), 1-butyl-3-methylimidazolium propionate ([C4mim][CH3CH 2COO]), and 1-butyl-3-methylimidazolium butyrate ([C 4mim][CH3(CH2)2COO]), in which the alkyl chain length in the anions is varied. The experimental viscosities (η) and conductivities (σ) for these ILs have been determined at different temperatures, and well correlated by the Vogel-Fulcher-Tammann (VFT) equation. Walden plots indicate an increase in ion pairs and/or ionic aggregates in the ILs with increasing alkyl chain length. Furthermore, the effect of alkyl chain length in carboxylate anions on viscosities and conductivities of the ILs has been discussed in light of the contribution from van der Waals interactions. Such knowledge would be useful for the understanding of the structure-property relationship of ILs and for the rational design of novel task-specific ILs.
On the Mechanism of the Reactivity of 1,3-Dialkylimidazolium Salts under Basic to Acidic Conditions: A Combined Kinetic and Computational Study
Rico del Cerro, Daniel,Mera-Adasme, Raúl,King, Alistair W. T.,Perea-Buceta, Jesus E.,Heikkinen, Sami,Hase, Tapio,Sundholm, Dage,W?h?l?, Kristiina
, p. 11613 - 11617 (2018)
Comprehensive spectroscopic kinetic studies illustrate an alternative mechanism for the traditional free-carbene intermediated H/D exchange reaction of 1,3-dialkylimidazolium salts under neutral (D2O) and acidic conditions (DCl/D2O 35 wt % solution). The deuteration of high purity [bmim]Cl in D2O is studied at different temperatures, in absence of catalyst or impurities, to yield an activation energy. DFT transition-state modelling, of a small water cluster and [bmim] cation, also yields an activation energy which strongly supports the proposed mechanism. The presence of basic impurities are shown to significantly enhance the exchange reaction, which brings into question the need for further analysis of technical purities of ionic liquids and the implications for a wide range of chemical reactions in such media.
Salting-out effect of ionic liquids on poly(propylene glycol) (PPG): Formation of PPG + ionic liquid aqueous two-phase systems
Wu, Changzeng,Wang, Jianji,Pei, Yuanchao,Wang, Huiyong,Li, Zhiyong
, p. 5004 - 5008 (2010)
In the present work, aqueous poly(propylene glycol) (PPG) solution was separated into aqueous two-phase systems (ATPSs) in the presence of ionic liquid 1-allyl-3-methylimidazolium chloride ([Amim]Cl), 1-butyl-3-methylimidazolium acetate ([C4mim]Ac), or 1-butyl-3-methylimidazolium chloride ([C 4mim]Cl). The top phase was PPG-rich, whereas the bottom phase was ionic liquid (IL)-rich. Liquid-liquid equilibrium data for the ATPSs and the salting-out coefficients of the ILs have been determined at 298.15 K and atmospheric pressure. It was shown that the binodal curves and the tie-lines could be described by a three-parameter equation and the Othmer-Tobias and Bancroft equations, respectively. The salting-out ability of the ILs on PPG was found to follow the order: [Amim]Cl > [C4mim]Ac > [C 4mim]Cl > [C4mim][BF4]. Since PPG is a thermo-sensitive polymer and can be recovered simply by heating, these novel ATPSs are expected to have applications in the recycling and/or enrichment of hydrophilic ILs from aqueous solutions.
Cellulose dissolution at ambient temperature: Role of preferential solvation of cations of ionic liquids by a cosolvent
Xu, Airong,Zhang, Yajuan,Zhao, Yang,Wang, Jianji
, p. 540 - 544 (2013)
Highly effective cellulose solvents for the dissolution of cellulose at ambient temperature have been designed by adding any aprotic polar solvent to 1-butyl-3-methylimidazolium acetate ([C4mim][CH3COO]). The effects of molar ratio o
Effect of alkyl chain length in anion on dissolution of cellulose in 1-butyl-3-methylimidazolium carboxylate ionic liquids
Xu, Airong,Zhang, Yibo,Lu, Weiwei,Yao, Kaisheng,Xu, Hang
, p. 211 - 214 (2014)
In recent years, 1-butyl-3-methylimidazolium carboxylate ionic liquids (ILs) have been reported to be powerful solvents for cellulose. However, little is known for the influence of the chain length in carboxylate anion on the solubility of cellulose. Therefore, in this work, we have synthesized 1-butyl-3-methylimidazolium carboxylate ILs including 1-butyl-3- methylimidazolium formate ([C4mim][HCOO]), acetate ([C 4mim][CH3COO]), propionate ([C4mim][CH 3CH2COO]) and butyrate ([C4mim][CH 3(CH2)2COO]), in which the alkyl chain length in the carboxylate anion is being varied. Solubilities of cellulose in the ILs have been determined experimentally at 70 °C. The effect of the chain length in carboxylate anion on the solubility of cellulose has been estimated and investigated by 1H NMR. Meanwhile, the regenerated cellulose from the ILs were investigated by scanning electron micrograph (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. Such knowledge would enhance our understanding of the design of novel ILs for cellulose.
The effect of the ionic liquid anion in the pretreatment of pine wood chips
Brandt, Agnieszka,Hallett, Jason P.,Leak, David J.,Murphy, Richard J.,Welton, Tom
, p. 672 - 679 (2010)
The effect of the anion of ionic liquids on air-dried pine (Pinus radiata) has been investigated. All ionic liquids used in this study contained the 1-butyl-3-methylimidazolium cation; the anions were trifluoromethanesulfonate, methylsulfate, dimethylphosphate, dicyanamide, chloride and acetate. Using a protocol for assessing the ability to swell small wood blocks (10 × 10 × 5 mm), it was shown that the anion has a profound impact on the ability to promote both swelling and dissolution of biomass. Time course studies showed that viscosity, temperature and water content were also important parameters influencing the swelling process. We used Kamlet-Taft parameters to quantify the solvent polarity of the ionic liquids and found that the anion basicity described by the parameter β correlated with the ability to expand and dissolve pine lignocellulose. It is shown that 1-butyl-3-methylimidazolium dicyanamide dissolves neither cellulose nor lignocellulosic material.
Effects of anionic structure and lithium salts addition on the dissolution of cellulose in 1-butyl-3-methylimidazolium-based ionic liquid solvent systems
Xu, Airong,Wang, Jianji,Wang, Huiyong
, p. 268 - 275 (2010)
Cellulose is the most abundant biorenewable and biodegradable resource on the earth. However, the extent of its application is limited due to its inefficient dissolution in solvents. Thus, the development of new cellulose solvents continues to be an activ
Rhodium nanoparticles impregnated on TiO2: Strong morphological effects on hydrogen production
Albuquerque, Brunno L.,Chacón, Gustavo,Nazarkovsky, Michael,Dupont, Jairton
, p. 13249 - 13258 (2020)
The effect of the shape of rhodium nanoparticles impregnated on TiO2 on photocatalytic hydrogen generation using methanol as a sacrificial reagent has been investigated by using a simple home-made UV-LED light strip reactor to activate the catalyst surface. For rhodium nanocubes, the normalised rate of H2 production was 22.4 mmol h-1 m-2 at 365 nm and 7.5 mmol h-1 m-2 at 400 nm. The normalised activity/surface area of the studied Rh nanoparticles showed a trend that led to establishing a relationship between the exposed [100] facets and photocatalytic activity. The Rh shape-dependent H2 production follows a trend of cubic > spherical > octahedral, which is associated with a higher surface energy of the Rh nanoparticles. This journal is
Interactions of 1-butyl-3-methylimidazolium carboxylate ionic liquids with glucose in water: A study of volumetric properties, viscosity, conductivity and NMR
Zhuo, Kelei,Chen, Yujuan,Chen, Jing,Bai, Guangyue,Wang, Jianji
, p. 14542 - 14549 (2011)
Extensive applications of ionic liquids (ILs) may result in their accumulation in the ecological environment and organisms. Although ILs are popularly called "green solvents", their toxicity, in fact, has been exhibited. Therefore the interaction of ILs with biomolecules is a cutting-edge research subject. Herein, the interactions of 1-butyl-3-methylimidazolium carboxylate ionic liquids ([C4mim][HCOO], [C4mim][CH 3COO] and [C4mim][CH3CH2COO]) with glucose in water were studied for their volumetric properties, viscosity, conductivity and NMR spectra. Limiting apparent molar volumes (V0Φ,IL), viscosity B-coefficients, limiting molar conductivities (Λ0) and Walden products (Λ0η0) were evaluated for the ILs in glucose + water solutions. Volumetric interaction parameters were also obtained from the transfer volumes of the ionic liquids. The contributions of the solvent properties (B1) and the ionic liquid-solvent interactions (B2) to the B-coefficient were extracted, together with molar activation energies (Δμ0≠IL) of the ionic liquids for viscous flow of the aqueous glucose + IL solution. In addition, the 13C and 1H NMR spectra of methyl β-d-glucopyranoside and ILs in β-d-glucopyranoside + IL + D2O were studied. The NMR results show that no special and strong interactions were observed between glucopyranoside and the ILs. However, it was confirmed that the H2 on the imidazolium ring has more activity (acidity) than atoms H4 and H5. The macro-properties and their changes were also discussed in terms of the size, structure and solvation of the ILs and glucose. the Owner Societies 2011.
Experimental and theoretical studies on solvation in aqueous solutions of ionic liquids carrying different side chains: the n-butyl-group versus the methoxyethyl group
De Jesus, Jessica C.,Pires, Paulo A. R.,Mustafa, Rizwana,Riaz, Naheed,El Seoud, Omar A.
, p. 15952 - 15963 (2017)
We used solvatochromic compounds to probe solvation in mixtures of water, W, and four ionic liquids (ILs), 1-R-3-methylimidazoliumX, where R = n-butyl or methoxyethyl and X = acetate and chloride; these are denoted as (C4MeImAc), (C3OMeImAc), (C4MeImCl), and (C3OMeImCl). Our aim was to investigate the effects on solvation when an ether linkage is substituted for a-CH2-group in the IL side chain. We used the solvatochromic probes 2,6-dichloro-4-(2,4,6-triphenylpyridinium-1-yl)phenolate (WB) and 5-nitroindoline, 1-methyl-5-nitroindoline to determine the solvent polarity, ET(WB), and Lewis basicity, SB, respectively. From UV-Vis spectral data, we calculated ET(WB) as a function of the water mole fraction (χW) at different temperatures; from 15 to 60 °C for WB in IL-acetate-W; 25 °C for SB and WB in IL-chloride-W. For all IL-W mixtures, the dependence of ET(WB) on χW is non-linear and, surprisingly, shows negligible dependence on the nature of the side chain. Values of the SB of IL-W were higher for C4MeImX-W than for C3OMeImX. A rationale for these results is the deactivation of the ether oxygen due to the formation of intramolecular hydrogen bonds with the hydrogens of the imidazolium ring. Our hypothesis is confirmed by quantum chemistry and molecular dynamics calculations (energy of the conformers and radial distribution functions), density, and 1H NMR data (chemical shifts, line widths). We attributed the non-linear dependence of the solvatochromic parameters on χW to preferential solvation of the dyes. We treated ET(WB) data with a model that includes the formation of the complex solvent IL-W. Equilibrium constants for solvent exchange in the solvation layer of WB were calculated; their values showed that IL-W is the most efficient solvent species present.
