- Direct reduction of carbon dioxide to formate in high-gas-capacity ionic liquids at post-transition-metal electrodes
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As an approach to combat the increasing emissions of carbon dioxide in the last 50 years, the sequestration of carbon dioxide gas in ionic liquids has become an attractive research area. Ionic liquids can be made that possess incredibly high molar absorption and specificity characteristics for carbon dioxide. Their high carbon dioxide solubility and specificity combined with their high inherent electrical conductivity also creates an ideal medium for the electrochemical reduction of carbon dioxide. Herein, a lesser studied ionic liquid, 1-ethyl-3-methylimidazolium trifluoroacetate, was used as both an effective carbon dioxide capture material and subsequently as an electrochemical matrix with water for the direct reduction of carbon dioxide into formate at indium, tin, and lead electrodes in good yield (ca. 3 mg hr-1 cm -2).
- Watkins, John D.,Bocarsly, Andrew B.
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- Heat capacities and excess enthalpies of 1-3ethyl-3-methylimidazolium-based ionic liquids and water
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Heat capacities and excess enthalpies were determined for three different binary water + ionic liquid systems, from (283.15 to 348.15) K, and covering the entire composition range. Specifically, the three completely water-miscible ionic liquids used were 1-ethyl-3-methylimidazolium ethylsulfate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, and 1-ethyl-3- methylimidazolium trifluoroacetate. The influence of temperature and composition was assessed, and suitable equations were used to correlate the experimental data. In addition, it was found that 1-ethyl-3-methylimidazolium ethylsulfate decomposes in the presence of water to form 1-ethyl-3-methylimidazolium hydrogen sulfate and ethanol under ambient conditions.
- Ficke, Lindsay E.,Rodriguez, Hector,Brennecke, Joan F.
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- Temperature and composition dependence of the density and viscosity of binary mixtures of water + ionic liquid
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Density and viscosity were determined for binary mixtures of water and three ionic liquids: 1-ethyl-3-methylimidazolium ethylsulfate, 1-ethyl-3-methylimidazolium trifluoroacetate, and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate. The experimental measurements of these properties were carried out at atmospheric pressure and temperatures from (278.15 to 348.15) K. The temperature dependence of density and viscosity for these systems can be described by an empirical second-order polynomial and by the Vogel - Fulcher - Tammann equation, respectively. Excess molar volumes and viscosity deviations were calculated and correlated by Redlich - Kister polynomial expansions. The latter correlations describe the variation of density and viscosity with composition. Comparison of the results for the three binary systems elucidates the influence of the anion on these physical properties.
- Rodriguez, Hector,Brennecke, Joan F.
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- Physicochemical properties of [Cnmim][TFA] (n = 2, 3, 4, 5, 6) ionic liquids
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A series of ionic liquids based on trifluoroacetic acid, namely, [Cnmim][TFA] (n = 2, 3, 4, 5, 6) (1-alkyl-3-methylimidazolium trifluoroacetate), were designed and synthesized. The density, surface tension and refractive index were measured in the temperature range of 293.15 to 343.15 ± 0.05 K, and some physicochemical properties of the ILs were calculated. Using the concept of molar surface Gibbs free energy, the traditional E?tv?s equation was improved into a modified E?tv?s equation, in which the intercept and the slope represented the molar surface enthalpy and the molar surface entropy, respectively, for [Cnmim][TFA] (n = 2, 3, 4, 5, 6). The thermal expansion coefficient (α) of [Cnmim][TFA] was calculated according to the interstitial model, and the order of magnitude of the calculated values was in good agreement with the corresponding experimental values. A new hypothesis was proposed, stating that the interstitial molar surface Gibbs free energy (gs) is not determined by the type of IL. From the refractive index and the molar surface Gibbs free energy, an equation to predict the surface tension of ILs was derived and the predicted values were highly correlated with the corresponding experimental values. Finally, a new polarity scale for ILs was developed, and the polarity order of the [Cnmim][TFA] (n = 2, 3, 4, 5, 6) ILs was estimated.
- Fang, Da-Wei,Zhang, Fang,Jia, Rui,Shan, Wei-jun,Xia, Li-xin,Yang, Jia-zhen
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- Solubility of sugars and sugar alcohols in ionic liquids: Measurement and PC-SAFT modeling
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Biorefining processes using ionic liquids (ILs) require proper solubility data of biomass-based compounds in ILs, as well as an appropriate thermodynamic approach for the modeling of such data. Carbohydrates and their derivatives such as sugar alcohols represent a class of compounds that could play an important role in biorefining. Thus, in this work, the pure IL density and solubility of xylitol and sorbitol in five different ILs were measured between 288 and 339 K. The ILs under consideration were 1-ethyl-3-methylimidazolium dicyanamide, 1-butyl-3-methylimidazolium dicyanamide ([bmim][DCA]), Aliquat dicyanamide, trihexyltetradecylphosphonium dicyanamide, and 1-ethyl-3-methylimidazolium trifluoroacetate. Comparison with the literature data was performed, showing good agreement. With the exception of [bmim][DCA], the solubility of these sugar alcohols in the other ILs is presented for the first time. The measured data as well as previously published solubility data of glucose and fructose in these ILs were modeled by means of PC-SAFT using a molecular-based associative approach for ILs. PC-SAFT was used in this work as it has shown to be applicable to model the solubility of xylitol and sorbitol in ILs (Paduszynì?ski;et al. J. Phys. Chem. B 2013, 117, 7034-7046). For this purpose, three pure IL parameters were fitted to pure IL densities, activity coefficients of 1-propanol at infinite dilution in ILs, and/or xylitol solubility in ILs. This approach allows accurate modeling of the pure IL data and the mixture data with only one binary interaction parameter kij between sugar and the IL or sugar alcohol and the IL. In cases where only the pure IL density and activity coefficients of 1-propanol at infinite dilution in ILs were used for the IL parameter estimation, the solubility of the sugars and sugar alcohols in the ILs could be predicted (kij = 0 between sugar and the IL or sugar alcohol and the IL) with reasonable accuracy. ? 2013 American Chemical Society.
- Carneiro, Aristides P.,Held, Christoph,Rodriì?guez, Oscar,Sadowski, Gabriele,Macedo, Eugeì?nia A.
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- Convenient synthesis of perfluoroalkyltrifluoroborates
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Perfluoroalkyltrimethoxyborates were converted into the corresponding perfluoroalkyltrifluoroborates in high yield by the action of potassium bifluoride in acidic media, i.e. in hydrochloric acid (37%), glacial acetic acid, and trifluoroacetic acid as wel
- Sprenger, Jan A.P.,Kerpen, Christoph,Ignat'ev, Nikolai,Finze, Maik
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- Experimental research on no2 viscosity and absorption for (1-ethyl-3-methylimidazolium trifluoroacetate + triethanolamine) binary mixtures
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The viscosity (9.34–405.92 mPa·s) and absorption capacity (0.4394–1.0562 g·g?1 ) of (1-ethyl-3-methylidazolium trifluoroacetate + triethanolamine) binary blends atmospheric pressure in the temperature range of 303.15–343.15 K and at different mole fractions of [EMIM] [TFA] have been carried out. The molar fraction of [EMIM] [TFA] dependence of the viscosity and absorption capacity was demonstrated. The addition of a small amount of [EMIM] [TFA] into TEA led to rapidly decreased rates of binary blends’ viscosity and absorption capacity. However, the viscosity and absorption of binary blends did not decrease significantly when [EMIM] [TFA] was increased to a specific value. Compared with the molar fraction of the solution, the temperature had no obvious effect on viscosity and absorption capacity. By modeling and optimizing the ratio of viscosity and absorption capacity of ([EMIM] [TFA] + TEA), it is proven that when the mole fraction of [EMIM] [TFA] is 0.58, ([EMIM] [TFA] + TEA) has the best viscosity and absorption capacity at the same time. In addition, at 303.15 K, ([EMIM] [TFA] + TEA) was absorbed and desorbed six times, the absorption slightly decreased, and the desorption increased.
- Jin, Nanxi,Liu, Baoyou,Tian, Jie,Wang, Xinyu,Yang, Huilong,Zhang, Peiwen
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- Induction of lignin solubility for a series of polar ionic liquids by the addition of a small amount of water
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Addition of a small amount of water was found to induce the lignin solubilizing ability in several polar ionic liquids which showed no lignin solubility in the absence of water. Similarly, addition of water was found to enhance lignin solubility in many polar ionic liquids. Though addition of water lowered the proton accepting ability of these ionic liquids, their proton donating ability was found to increase. The lignin dissolution by ionic liquids was newly found to be a function of both the proton accepting ability and proton donating ability of the ionic liquids. Water is a poor solvent for polysaccharides, and water addition has therefore been confirmed to be effective to improve the selective extraction yield of lignin from cedar powder under mild conditions.
- Akiba, Takashi,Tsurumaki, Akiko,Ohno, Hiroyuki
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supporting information
p. 2260 - 2265
(2017/07/24)
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- Redox Reaction: A New Route for the Synthesis of Water-Miscible Imidazolium Ionic Liquids
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A novel chemical redox route was developed for the preparation of water-miscible imidazolium ionic liquids (ILs). In this method, the reaction between 1-alkyl-3-methylimidazolium bromides or 3-butyl-1-phenylimidazolium bromide and the appropriate acid reactant was promoted by the redox reaction between the bromide ion and aqueous hydrogen peroxide, with hex-1-ene as both solvent and bromine scavenger. The residual bromide ion and water contents of the prepared ILs were determined by ion chromatography and the Karl-Fischer test, respectively. This method not only produces water-miscible ILs in high purity and high yield, but also simplifies the reaction conditions in comparison with previous routes.
- Li, Wenxiu,Dai, Shangwu,Li, Dong,Zhang, Qinqin,Fan, Hongtao,Zhang, Tao,Zhang, Zhigang
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p. 1065 - 1072
(2017/02/23)
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- 1,3-Dimethylimidazolium-2-carboxylate: A zwitterionic salt for the efficient synthesis of vicinal diols from cyclic carbonates
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The development of efficient, cheap and recyclable catalysts for reactions under mild reaction conditions is a very attractive topic in green chemistry. Herein, a series of basic ionic liquids (ILs) were investigated as catalysts for the synthesis of vicinal diols via the hydrolysis of cyclic carbonates in order to improve this kind of synthetic process. The effects of the IL structure, the molar ratio of cyclic carbonate to water, and various reaction parameters on the catalytic performance were investigated in detail. It was found that 1,3-dimethylimidazolium-2-carboxylate, a simple halogen-free zwitterionic catalyst, showed high activity (a space-time yield of 1086 h-1) and excellent selectivity for the preparation of ethylene glycol via the hydrolysis of ethylene carbonate. The catalyst could be reused over six times without obvious loss of catalytic activity. Also, it was applicable to a variety of cyclic carbonates for the production of their corresponding vicinal diols with high yields and selectivities. A possible catalytic cycle for this kind of catalytic process was proposed based on the experimental results, NMR spectroscopy and theoretical calculations. This reaction protocol opens a new possibility for chemical synthesis as a substitution for traditional base or basic ILs. This journal is the Partner Organisations 2014.
- Sun, Jian,Yao, Xiaoqian,Cheng, Weiguo,Zhang, Suojiang
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supporting information
p. 3297 - 3304
(2014/06/10)
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- Arylation of sensitive 1-(Pyrrolidin-1-yl)-diazen-1-ium-diolate in ionic liquids
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The purpose of this research was to investigate the stability and reactivity of 1-(pyrrolidin-1-yl)diazen-1-ium-1,2-diolate (PYRRO/NO) in dimethylformamide (DMF, as the reference solvent) and compare them to those obtained using different ionic liquids. The results of our experiments showed that PYRRO/NO is more stable (based on reactivity) in ionic liquid [EMIM][Ms] (with reaction yields up to 52%) than in DMF, that substitution products can be separated directly and quantitatively from the ionic liquid using a single flash-column separation, and that the ionic liquids can also be recovered and reused in a second iteration of the same reaction to achieve similar yields.
- Velazquez, Carlos A.,Lynn, Geoffrey M.,Kumar, Vineet,Keefer, Larry K.,Malhotra, Sanjay V.
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experimental part
p. 1322 - 1332
(2010/07/04)
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- PROCESS FOR PREPARING IONIC LIQUIDS BY ANION EXCHANGE
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Process for preparing salts of the formula I [in-line-formulae](B+)nxAy?[/in-line-formulae] where B is a cation comprising at least one nitrogen atom, A is an anion and n is an integer from 1 to 3, x and y are each an integer from 1 to 3 and the product of x and y is equal to n, by reacting salts of the formula II [in-line-formulae](B+)nxAy?[/in-line-formulae] where B and n, x and y are as defined above and C is a compound which has one or more carboxylate groups (referred to as carboxylate for short) and is different from A, with the ammonium salt of the anion A or with the protic acid of the anion A in the presence of ammonia.
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Page/Page column 9
(2010/09/05)
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- METHOD FOR PRODUCING ONIUM SALTS COMPRISING ALKYL ANIONS OR ARYL SULFONATE ANIONS OR ALKYL ANIONS OR ARYL CARBOXYLATE ANIONS HAVING A LOW HALIDE CONTENT
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The invention relates to a method for producing onium salts comprising alkyl anions or aryl sulfonate anions or alkyl carboxylate anions or acryl carboxylate anions by reacting an onium halide with an alkyl silyl ester or trialkyl silyl ester of an alkyl sulfonic acid or aryl sulfonic acid or an alkyl carboxylic acid or aryl carboxylic acid or the anhydrides thereof.
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Page/Page column 37-38
(2008/06/13)
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- Organic salt conditioner, organic salt-containing composition, and uses thereof
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The present invention relates to the use of, and a composition containing, at least one non-polymeric organic salt with a melting point of less than 60° C. These organic salts may be imidazolium, pyrazolium, pyridinium, pyrimidinium or tetraalkylphosphonium salts. The inventinon composition may be used for washing (cleaning) and/or conditioning keratin materials, and especially the hair.
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- Process for preparing ambient temperature ionic liquids
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A process for preparing an ionic liquid or salt, preferably in which the cation comprises an N-alkylated base and the anion is a carboxylate, formed by reaction between an organic base and an alkylating agent, wherein the alkylating agent is a fluorinated ester or an alkyl sulfonate, is described. Suitable organic bases include imizadoles, substituted imidazoles, pyridines and substituted pyridines. The so-formed products can be subsequently transformed into different ionic liquids or salts by metathesis.
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- Electrophilic nitration of aromatics in ionic liquid solvents
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Potential utility of a series of 1-ethyl-3-methylimidazolium salts [emim][X] with X = OTf-, CF3COO-, and NO3- as well as [HNEtPri2][CF3COO] (protonated Huenig's base) ionic liquids were explored as solvent for electrophilic nitration of aromatics using a variety of nitrating systems, namely NH4NO3/TFAA, isoamyl nitrate/BF3·Et2O, isoamyl nitrate/TfOH, Cu(NO3)/TFAA, and AgNO3/Tf2O. Among these, NH4NO3/TFAA (with [emim][CF3COO], [emim][NO3]) and isoamyl nitrate/BF3·Et2O, isoamyl nitrate/TfOH (with [emim][OTf]) provided the best overall systems both in terms of nitration efficiency and recycling/reuse of the ionic liquids. For [NO2][BF4] nitration, the commonly used ionic liquids [emim][AlCl4] and [emim][Al2Cl7] are unsuitable, as counterion exchange and arene nitration compete. [Emim][BF4] is ring nitrated with [NO2][BF4] producing [NO2-emim][BF4] salt, which is of limited utility due to its increased viscosity. Nitration in ionic liquids is surveyed using a host of aromatic substrates with varied reactivities. The preparative scope of the ionic liquids was also extended. Counterion dependency of the NMR spectra of the [emim][X] liquids can be used to gauge counterion exchange (metathesis) during nitration. Ionic liquid nitration is a useful alternative to classical nitration routes due to easier product isolation and recovery of the ionic liquid solvent, and because it avoids problems associated with neutralization of large quantities of strong acid.
- Laali,Gettwert
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