262297-13-2Relevant academic research and scientific papers
Concentration-dependent apparent partition coefficients of ionic liquids possessing ethyl- and bi-sulphate anions
Jain, Preeti,Kumar, Anil
, p. 1105 - 1113 (2016)
This study deals with the concentration dependent apparent partition coefficients log P of the ethyl and bisulfate-based ionic liquids. It is observed that the bisulfate-based ionic liquids show different behaviour with respect to concentration as compared to ethyl sulphate-based ionic liquids. It is significant and useful analysis for the further implementation of alkyl sulfate based ionic liquids as solvents in extraction processes. The log P values of the ethyl sulphate-based ionic liquids were noted to vary linearly with the concentration of the ionic liquid, whereas a flip-flop trend with the concentration for the log P values of the bisulphate-based ionic liquids was observed due to the difference in hydrogen bond accepting basicity and possibility of aggregate formation of these anions. The π-π interactions between the imidazolium and pyridinium rings were seen to affect the log P values. The alkyl chain length of anions was also observed to influence the log P values. The hydrophobicity of ionic liquid changes with the alkyl chain in the anion in the order; [HSO4]- 4]- 4]-.
Fine tuning the ionic liquid-vacuum outer atomic surface using ion mixtures
Villar-Garcia, Ignacio J.,Fearn, Sarah,Ismail, Nur L.,McIntosh, Alastair J. S.,Lovelock, Kevin R. J.
, p. 5367 - 5370 (2015)
Ionic liquid-vacuum outer atomic surfaces can be created that are remarkably different from the bulk composition. In this communication we demonstrate, using low-energy ion scattering (LEIS), that for ionic liquid mixtures the outer atomic surface shows s
Choline chloride-thiourea, a deep eutectic solvent for the production of chitin nanofibers
Mukesh, Chandrakant,Mondal, Dibyendu,Sharma, Mukesh,Prasad, Kamalesh
, p. 466 - 471 (2014)
Deep eutectic solvents (DESs) consisting of the mixtures of choline halide (chloride/bromide)-urea and choline chloride-thiourea were used as solvents to prepare α-chitin nanofibers (CNFs). CNFs of diameter 20-30 nm could be obtained using the DESs comprising of the mixture of choline chloride and thiourea (CCT 1:2); however, NFs could not be obtained using the DESs having urea (CCU 1:2) as hydrogen bond donor. The physicochemical properties of thus obtained NFs were compared with those obtained using a couple of imidazolium based ionic liquids namely, 1-butyl-3-methylimidazolium hydrogen sulphate [(Bmim)HSO4] and 1-methylimidazolium hydrogen sulphate [(Hmim)HSO4] as well as choline based bio-ILs namely, choline hydrogen sulphate [(Chol)HSO4] and choline acrylate. The CNFs obtained using the DES as a solvent were used to prepare calcium alginate bio-nanocomposite gel beads having enhanced elasticity in comparison to Ca-alginate beads. The bio-nanocomposite gel beads thus obtained were used to study slow release of 5-fluorouracil, an anticancer drug.
Are alkyl sulfate-based protic and aprotic ionic liquids stable with water and alcohols? A thermodynamic approach
Jacquemin, Johan,Goodrich, Peter,Jiang, Wei,Rooney, David W.,Hardacre, Christopher
, p. 1938 - 1949 (2013)
The knowledge of the chemical stability as a function of the temperature of ionic liquids (ILs) in the presence of other molecules such as water is crucial prior to developing any industrial application and process involving these novel materials. Fluid phase equilibria and density over a large range of temperature and composition can give basic information on IL purity and chemical stability. The IL scientific community requires accurate measurements accessed from reference data. In this work, the stability of different alkyl sulfate-based ILs in the presence of water and various alcohols (methanol, ethanol, 1-butanol, and 1-octanol) was investigated to understand their stability as a function of temperature up to 423.15 K over the hydrolysis and transesterification reactions, respectively. From this investigation, it was clear that methyl sulfate- and ethyl sulfate-based ILs are not stable in the presence of water, since hydrolysis of the methyl sulfate or ethyl sulfate anions to methanol or ethanol and hydrogenate anion is undoubtedly observed. Such observations could help to explain the differences observed for the physical properties published in the literature by various groups. Furthermore, it appears that a thermodynamic equilibrium process drives these hydrolysis reactions. In other words, these hydrolysis reactions are in fact reversible, providing the possibility to re-form the desired alkyl sulfate anions by a simple transesterification reaction between hydrogen sulfate-based ILs and the corresponding alcohol (methanol or ethanol). Additionally, butyl sulfate- and octyl sulfate-based ILs appear to follow this pattern but under more drastic conditions. In these systems, hydrolysis is observed in both cases after several months for temperatures up to 423 K in the presence of water. Therein, the partial miscibility of hydrogen sulfate-based ILs with long chain alcohols (1-butanol and 1-octanol) can help to explain the enhanced hydrolytic stability of the butyl sulfate- and octyl sulfate-based ILs compared with the methyl or ethyl sulfate systems. Additionally, rapid transesterification reactions are observed during liquid-liquid equilibrium studies as a function of temperature for binary systems of (hydrogen sulfate-based ionic liquids + 1-butanol) and of (hydrogen sulfate-based ionic liquids + 1-octanol). Finally, this atom-efficient catalyst-free transesterification reaction between hydrogen sulfate-based ILs and alcohol was then tested to provide a novel way to synthesize new ILs with various anion structures containing the alkyl sulfate group. ? 2013 American Chemical Society.
A quick, simple, robust method to measure the acidity of ionic liquids
Gr?svik, John,Hallett, Jason P.,To, Trang Quynh,Welton, Tom
, p. 7258 - 7261 (2014)
Introduced here is a quick, simple, robust method to measure acidity in ionic liquid (IL) systems by the use of the NMR-probe mesityl oxide. Acidity corresponding to a Hammett acidity of -1 to -9 can be measured reliably using this technique, a range that vastly exceeds that of any single UV-vis probe.
Oxidative desulfurization of gasoline by ionic liquids coupled with extraction by organic solvents
Abro, Rashid,Gao, Shurong,Chen, Xiaochun,Yu, Guangren,Abdeltawab Salem, Ahmed A.,Al-Deyabb
, p. 998 - 1006 (2016)
In this work, desulfurization of real fluidized catalytic cracking (FCC) gasoline was investigated in dual steps; first in oxidative desulfurization (ODS) using imidazolium and pyrrolidonium based Br?nsted acidic ionic liquids (ILs) as solvent and catalyst and hydrogen peroxide as oxidant. In second step, extractive desulfurization took place using organic solvents of furfural, furfural alcohol and ethylene glycol. Variety of factors such as temperature, time, mass ratio of oil/ILs and regeneration and recycling of ILs, multiple-step desulfurization of ILs and organic solvents and solvent/oil ratio were also investigated. The S-content was significantly decreased to ca. 18 ppm from initial S-content of 260 ppm with a total S-removal of ca. 95percent in one-step ODS using pyrrolidonium based ILs coupled with five-step extraction desulfurization (EDS) using furfural alcohol as extractant. This work shows that oxidative desulfurization using ionic liquids coupled with extractive desulfurization using organic solvents is a potential method to produce clean gasoline.
Efficient combination of recyclable task specific ionic liquid and microwave dielectric heating for the synthesis of lipophilic esters
Arfan, Atef,Bazureau, Jean Pierre
, p. 743 - 748 (2005)
Mild and efficient esterification reactions of carboxylic acids with neo-pentanol were carried out using task-specific ionic liquids with hydrogen sulphate counteranion under microwave irradiation. The latent acidity of the ionic liquid was introduced by
Influence of anions of imidazole ionic liquids on dissolution of cellulose
Liu,Yu,Zhou,Zhang,Zhang
, p. 8266 - 8270 (2013)
[Bmim]Cl, [Bmim]Br, [Bmim]HSO4, [Bmim]BF4 and [Bmim]PF6 were synthesized to study the influence of anions on the dissolution of cellulose. Experimental studies showed that the dissolution of cellulose was related to the formation of hydrogen bonds between the anions and cellulose, which is attributed to the charge density on the anion. The sequence of solubility of cellulose in six ionic liquids tested was [Bmim]Cl > [Bmim]Br > [Bmim]HSO4 > [Bmim]BF4, [Bmim]PF 6. Thermogravimetric method was employed to investigate the stability of ionic liquids. The dissolution process was monitored with polarizing microscope. The results showed that dissolution of cellulose was related to stability of the ionic liquids. For similar ionic liquids, poorer stability led to higher solubility. Both the original and regenerated cellulose samples were characterized with wide-angle X-ray diffraction and FTIR. It was shown that the structures of original cellulose and regenerated cellulose were similar; however, the crystalline structure of cellulose was converted to cellulose II from cellulose I of the original cellulose.
Development of Acidic Imidazolium Ionic Liquids for Activation of Kraft Lignin by Controlled Oxidation: Comprehensive Evaluation and Practical Utility
Klapiszewski, ?ukasz,Szalaty, Tadeusz J.,Kurc, Beata,Stanisz, Ma?gorzata,Zawadzki, Bartosz,Skrzypczak, Andrzej,Jesionowski, Teofil
, p. 361 - 374 (2018)
A novel, eco-friendly method for the activation of lignin by controlled oxidation was studied. The results obtained for six acidic imidazolium ionic liquids containing the hydrogen sulfate anion were compared. The key goal of this research was to increase the content of carbonyl groups in the lignin structure because these may play the main role in the transport of protons and electrons in active materials for electrochemical applications. By means of a variety of analytical techniques (FTIR, 13C CP/MAS NMR, and X-ray photoelectron spectroscopy; selected reactions to determine the presence of carbonyl groups; SEM; zeta-potential analysis; thermogravimetric analysis/differential thermogravimetric analysis; and porous structure analysis), it was determined that the product obtained after treatment with 3-cyclohexyloxymethy-1-methylimidazolium hydrogen sulfate had favorable properties, in terms of the target application. Electrochemical tests proved that the obtained materials could be used as anodes in lithium batteries. The results show that the activation of lignin with ionic liquids can increase its capacity and maintain stability.
The efficient hydroxyalkylation of phenol with formaldehyde to bisphenol F over a thermoregulated phase-separable reaction system containing a water-soluble Bronsted acidic ionic liquid
Wang, Qing,Wu, Zhi Min,Li, Yongfei,Tan, Ying,Liu, Ning,Liu, Yuejin
, p. 33466 - 33473 (2014)
The efficient hydroxyalkylation of phenol with formaldehyde to bisphenol F over a thermoregulated phase-separable reaction system containing a water-soluble Bronsted acidic ionic liquid was studied. The reaction system containing the water-soluble IL showed thermoregulated biphasic behavior with change of the alkyl chain length of IL, temperature and water amount. Four types of imidazolium-, ammonium-, phosphonium- and pyridinium-based water-soluble ionic liquids with different anions of dihydrogen phosphate [H2PO4]-, acetate [CH3COO] - and hydrogen sulfate [HSO4]- were used as both Bronsted acidic catalysts and thermoregulated solvents. Among them, [C6MIM][HSO4] gave a high yield of 80.5% and a selectivity of 96.9% for bisphenol F, and the optimal reaction conditions were stirring speed 450 rpm, phenol-formaldehyde ratio 6:1, IL catalyst molar concentration 12.5%, reaction temperature 90 °C and reaction time 1 h. [C 6MIM][HSO4] could be recovered by simple decantation and could retain its original activity even after six recycling-uses [C nMIM][HSO4] with the alkyl chain length n = 6 found to be the most suitable for the synthesis of bisphenol F because of both the formation of a thermoregulated monophasic reaction system at 90 °C to enhance the reaction efficiency and as a thermoregulated phase-transition solvent to facilitate its recovery from the reaction system. the Partner Organisations 2014.
