http://www.mdpi.com/journal/molecules/special_issues/ionic-liquids-molecules/ {snippet name="submission_info"} http://www.mdpi.com/1420-3049/15/4/2405/ Ionic liquids (ILs) have been applied in different areas of separation, such as ionic liquid supported membranes, as mobile phase additives and surface-bonded stationary phases in chromatography separations and as the extraction solvent in sample preparations, because they can be composed from various cations and anions that change the properties and phase behavior of liquids. Although the applications of ILs in separations are still in their early stages, the academic interest in ILs is increasing. An overview of the principle applications of ILs in separation technology is present in this work. Furthermore, the prospects of the ILs in separation techniques are discussed. http://www.mdpi.com/1420-3049/15/4/2405/ Mon, 05 Apr 2010 00:00:00 CEST Molecules 2010-04-05 15 4 Review 2405 2426 1420-3049 Recent Applications of Ionic Liquids in Separation Technology 2010-04-05 doi: 10.3390/molecules15042405 Han Row http://www.mdpi.com/1420-3049/15/2/793/ We report on the solubility of hen lysozyme (HEWL) in aqueous ethylammonium nitrate (EAN) as a function of water content. We find the solubility behavior to be complex, exhibiting both a maximum (400 mg/mL) at very high EAN content) and a minimum at intermediate EAN content. We exploit this solubility profile in a novel approach to generating crystals of hydrophilic proteins, based on rehydration of a high concentration protein solution. We describe the production of crystals of X-ray diffraction quality. Two related ionic liquid solvent systems, with the same solubility profiles but different effective pH characteristics, are identified for future evaluation. http://www.mdpi.com/1420-3049/15/2/793/ Thu, 04 Feb 2010 00:00:00 CET Molecules 2010-02-04 15 2 Communication 793 803 1420-3049 The Solubility of Hen Lysozyme in Ethylammonium Nitrate/H2O Mixtures and a Novel Approach to Protein Crystallization 2010-02-04 doi: 10.3390/molecules15020793 Nolene Byrne C. Austen Angell http://www.mdpi.com/1420-3049/14/12/5001/ The pH-profiles of the extraction of Cs+ into four conventional (1-butyl-3-methylimidazolium hexafluorophosphate and bis[trifluoromethyl)sulphonyl]imides of 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, and 1-(2-ethylhexyl)-3- methylimidazolium) and two novel (trioctylmethylammonium salicylate and tetrahexylammonium dihexylsulfosuccinate) room temperature ionic liquids have been determined both in the absence and in the presence of crown ether (18-crown-6 or dibenzo-18-crown-6). The pH-profiles of distribution ratio of crown ethers have been established in the same conditions. The relationship of cesium extraction efficiency both with the stability of its complexes with crown ethers and crown ethers’ distribution ratio has been clarified. http://www.mdpi.com/1420-3049/14/12/5001/ Wed, 02 Dec 2009 00:00:00 CET Molecules 2009-12-02 14 12 Article 5001 5016 1420-3049 18-Crown-6 and Dibenzo-18-crown-6 Assisted Extraction of Cesium from Water into Room Temperature Ionic Liquids and Its Correlation with Stability Constants for Cesium Complexes 2009-12-02 doi: 10.3390/molecules14125001 Andrey Grigoryevich Vendilo Dmitry Ivanovich Djigailo Svetlana Valeryevna Smirnova Irina Ivanovna Torocheshnikova Konstantin Ivanovich Popov Vladimir Georgyevich Krasovsky Igor Vladimirovich Pletnev http://www.mdpi.com/1420-3049/14/11/4682/ Injection of a mixture of HAuCl4 and cellulose dissolved in the ionic liquid (IL) 1-butyl-3-methylimidazolium chloride [Bmim]Cl into aqueous NaBH4 leads to colloidal gold nanoparticle/cellulose hybrid precipitates. This process is a model example for a very simple and generic approach towards (noble) metal/cellulose hybrids, which could find applications in sensing, sterile filtration, or as biomaterials. http://www.mdpi.com/1420-3049/14/11/4682/ Wed, 18 Nov 2009 00:00:00 CET Molecules 2009-11-18 14 11 Article 4682 4688 1420-3049 Cellulose/Gold Nanocrystal Hybrids via an Ionic Liquid/Aqueous Precipitation Route 2009-11-18 doi: 10.3390/molecules14114682 Zhonghao Li Andreas Taubert http://www.mdpi.com/1420-3049/14/11/4396/ Ionic liquids (ILs) are known to be non-volatile and thus to have low potential for atmospheric contamination or intoxication of humans by inhalation. However ILs have the potential to contaminate soil and water as they might be water soluble and can be sorbed onto solids. The investigation of possible natural ways of reducing the concentration of ILs in the environment is of high importane, especially because the requirement for biodegradable chemicals increases, together with pressure for reduction of incineration and landfill waste. It was found that the upper concentration threshold for primary biodegradation of 1-methyl-3-octylimidazolium chloride is 0.2 mM. At higher concentrations the dehydrogenase activity of the cells dropped markedly, indicating that the IL inhibits cell activity. This concentration is in good agreement with the minimal inhibitory concentration of the same compound found for a series of bacteria and fungi by this research group. The sorption of 1-methyl-3-octylimidazolium chloride was found to be significant, and the sorption coefficient was determined to be 98.2 L kg-1. http://www.mdpi.com/1420-3049/14/11/4396/ Mon, 02 Nov 2009 00:00:00 CET Molecules 2009-11-02 14 11 Article 4396 4405 1420-3049 1-Methyl-3-octylimidazolium Chloride—Sorption and Primary Biodegradation Analysis in Activated Sewage Sludge 2009-11-02 doi: 10.3390/molecules14114396 Marta Markiewicz Christian Jungnickel Aleksandra Markowska Urszula Szczepaniak Monika Paszkiewicz Jan Hupka http://www.mdpi.com/1420-3049/14/11/4351/ In this work, an N-butyl-pyridinium-based ionic liquid [BPy]BF4 was prepared. The effect of extraction desulfurization on model oil with thiophene and dibenzothiophene (DBT) was investigated. Ionic liquids and hydrogen peroxide (30%) were tested in extraction-oxidation desulfurization of model oil. The results show that the ionic liquid [BPy]BF4 has a better desulfurization effect. The best technological conditions are: V(IL)/V(Oil) /V(H2O2) = 1:1:0.4, temperature 55 °C, the time 30 min. The ratio of desulfurization to thiophene and DBT reached 78.5% and 84.3% respectively, which is much higher than extraction desulfurization with simple ionic liquids. Under these conditions, the effect of desulfurization on gasoline was also investigated. The used ionic liquids can be recycled up to four times after regeneration. http://www.mdpi.com/1420-3049/14/11/4351/ Wed, 28 Oct 2009 00:00:00 CET Molecules 2009-10-28 14 11 Article 4351 4357 1420-3049 Oxidative Desulfurization of Fuel Oil by Pyridinium-Based Ionic Liquids 2009-10-28 doi: 10.3390/molecules14114351 Dishun Zhao Yanan Wang Erhong Duan http://www.mdpi.com/1420-3049/14/10/4275/ Preparation of (S)-1-chloro-2-octanol and (S)-1-bromo-2-octanol was carried out by the enzymatic hydrolysis of halohydrin palmitates using biocatalysts. Halohydrin palmitates were prepared by various methods from palmitic acid and 1,2-octanediol. A tandem hydrolysis was carried out using lipases from Candida antarctica (Novozym® 435), Rhizomucor miehei (Lipozyme IM), and “resting cells” from a Rhizopus oryzae strain that was not mycotoxigenic. The influence of the enzyme and the reaction medium on the selective hydrolysis of isomeric mixtures of halohydrin esters is described. Novozym® 435 allowed preparation of (S)-1-chloro-2-octanol and (S)-1-bromo-2-octanol after 1–3 h of reaction at 40 °C in [BMIM][PF6]. http://www.mdpi.com/1420-3049/14/10/4275/ Fri, 23 Oct 2009 00:00:00 CEST Molecules 2009-10-23 14 10 Communication 4275 4283 1420-3049 Preparation of (S)-1-Halo-2-octanols Using Ionic Liquids and Biocatalysts 2009-10-23 doi: 10.3390/molecules14104275 Mireia Oromí-Farrús Jordi Eras Núria Sala Mercè Torres Ramon Canela http://www.mdpi.com/1420-3049/14/9/3780/ Ionic liquids are novel solvents of interest as greener alternatives to conventional organic solvents aimed at facilitating sustainable chemistry. As a consequence of their unusual physical properties, reusability, and eco-friendly nature, ionic liquids have attracted the attention of organic chemists. Numerous reports have revealed that many catalysts and reagents were supported in the ionic liquid phase, resulting in enhanced reactivity and selectivity in various important reaction transformations. However, synthetic chemists cannot ignore the stability data and intermolecular interactions, or even reactions that are directly applicable to organic reactions in ionic liquids. It is becoming evident from the increasing number of reports on use of ionic liquids as solvents, catalysts, and reagents in organic synthesis that they are not totally inert under many reaction conditions. While in some cases, their unexpected reactivity has proven fortuitous and in others, it is imperative that when selecting an ionic liquid for a particular synthetic application, attention must be paid to its compatibility with the reaction conditions. Even though, more than 200 room temperature ionic liquids are known, only a few reports have commented their effects on reaction mechanisms or rate/stability. Therefore, rather than attempting to give a comprehensive overview of ionic liquid chemistry, this review focuses on the non-innocent nature of ionic liquids, with a decided emphasis to clearly illuminate the ability of ionic liquids to affect the mechanistic aspects of some organic reactions thereby affecting and promoting the yield and selectivity. http://www.mdpi.com/1420-3049/14/9/3780/ Fri, 25 Sep 2009 00:00:00 CEST Molecules 2009-09-25 14 9 Review 3780 3813 1420-3049 On the Chemical Stabilities of Ionic Liquids 2009-09-25 doi: 10.3390/molecules14093780 Subbiah Sowmiah Venkatesan Srinivasadesikan Ming-Chung Tseng Yen-Ho Chu http://www.mdpi.com/1420-3049/14/8/2935/ The oxo-diperoxo molybdenum(VI) complex MoO(O2)2•2QOH (QOH = 8-quinilinol) was prepared and characterized by elemental analysis, IR and UV-Vis spectra. The ionic liquids (ILs) [bmim][BF4], [hydemim][BF4], and [bmim][PF6] were characterized by 1H-NMR and UV-Vis spectra. The epoxidation of a technical mixture of methyl oleate and methyl linoleate with H2O2, in [bmim][BF4], [hydemim][BF4] and [bmim][PF6], catalyzed by MoO(O2)2•2QOH (QOH = 8-quinilinol) and with NaHCO3 as co-catalyst has been studied for the first time. It was found that high conversions of methyl oleate and methyl linoleate to their respective oxidation products, as well as the total selectivity of their oxidation products to oxirane in [hydemim][BF4] were obtained. Also, the IL phases containing the Mo(VI) catalyst can be readily recycled by washing with diethyl ether and drying, and the Mo(VI) catalyst can be reused at least five times. http://www.mdpi.com/1420-3049/14/8/2935/ Mon, 10 Aug 2009 00:00:00 CEST Molecules 2009-08-10 14 8 Article 2935 2946 1420-3049 Catalytic Epoxidation of a Technical Mixture of Methyl Oleate and Methyl Linoleate in Ionic Liquids Using MoO(O2)2•2QOH (QOH = 8-quinilinol) as Catalyst and NaHCO3 as co-Catalyst 2009-08-10 doi: 10.3390/molecules14082935 Shuang-Fei Cai Li-Sheng Wang Chuan-Lei Fan http://www.mdpi.com/1420-3049/14/8/2888/ Ionic liquids (ILs) are finding technological applications as chemical reaction media and engineering fluids. Some emerging fields are those of lubrication, surface engineering and nanotechnology. ILs are thermally stable, non-flammable highly polar fluids with negligible volatility, these characteristics make them ideal candidates for new lubricants under severe conditions, were conventional oils and greases or solid lubricants fail. Such conditions include ultra-high vacuum and extreme temperatures. Other very promising areas which depend on the interaction between IL molecules and material surfaces are the use of ILs in the lubrication of microelectromechanic and nanoelectromechanic systems (MEMS and NEMS), the friction and wear reduction of reactive light alloys and the modification of nanophases. http://www.mdpi.com/1420-3049/14/8/2888/ Tue, 04 Aug 2009 00:00:00 CEST Molecules 2009-08-04 14 8 Review 2888 2908 1420-3049 Ionic Liquids as Advanced Lubricant Fluids 2009-08-04 doi: 10.3390/molecules14082888 María-Dolores Bermúdez Ana-Eva Jiménez José Sanes Francisco-José Carrión http://www.mdpi.com/1420-3049/14/7/2521/ While there has been much effort in recent years to characterise ionic liquids in terms of parameters that are well described for molecular solvents, using these to explain reaction outcomes remains problematic. Herein we propose that many reaction outcomes in ionic liquids may be explained by considering the electrostatic interactions present in the solution; that is, by recognising that ionic liquids are salts. This is supported by evidence in the literature, along with studies presented here. http://www.mdpi.com/1420-3049/14/7/2521/ Mon, 13 Jul 2009 00:00:00 CEST Molecules 2009-07-13 14 7 Article 2521 2534 1420-3049 Ionic Liquids: Just Molten Salts After All? 2009-07-13 doi: 10.3390/molecules14072521 Hon Man Yau Si Jia Chan Stephen R. D. George James M. Hook Anna K. Croft Jason B. Harper http://www.mdpi.com/1420-3049/14/7/2394/ The transformations of organic molecules with F-TEDA-BF4 (1) were investigated in the hydrophilic ionic liquid (IL) 1-butyl-3-methyl-imidazolium tetrafluoroborate ([bmim][BF4], 2) and the hydrophobic IL 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6], 3). The range of substrates included alkyl substituted phenols 4a-c, 9, 13, 1,1-diphenylethene (15), alkyl aryl ketones 19-22, aldehydes 23-25 and methoxy-substituted benzene derivatives 26-30. The evaluation of the outcome of reactions performed in IL media in comparison to those of the corresponding reactions in conventional organic solvents revealed that the transformations in IL are less efficient and selective. The effect of the presence of a nucleophile (MeOH, H2O, MeCN) on the course of reaction was also studied. http://www.mdpi.com/1420-3049/14/7/2394/ Mon, 06 Jul 2009 00:00:00 CEST Molecules 2009-07-06 14 7 Article 2394 2409 1420-3049 Transformations of Organic Molecules with F-TEDA-BF4 in Ionic Liquid Media 2009-07-06 doi: 10.3390/molecules14072394 Jasminka Pavlinac Marko Zupan Stojan Stavber http://www.mdpi.com/1420-3049/14/6/2286/ Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided. http://www.mdpi.com/1420-3049/14/6/2286/ Wed, 24 Jun 2009 00:00:00 CEST Molecules 2009-06-24 14 6 Review 2286 2305 1420-3049 Ionic Liquids in Tribology 2009-06-24 doi: 10.3390/molecules14062286 Ichiro Minami http://www.mdpi.com/1420-3049/14/6/2235/ A convenient route for the preparation of C2-substituted imidazolium ionic liquids is reported. This method involves the alkylation of N-heterocyclic carbenes, which are readily generated from the C2-unsubstituted imidazolium ionic liquids. It works well for non-functionalized alkyl chlorides, and less well for alkyl bromides and iodides, likely due to competing elimination reactions. The resulting C2-substituted salts can be transformed into ionic liquids via standard anion metathesis reactions. http://www.mdpi.com/1420-3049/14/6/2235/ Fri, 19 Jun 2009 00:00:00 CEST Molecules 2009-06-19 14 6 Article 2235 2245 1420-3049 A Facile Route to C2-Substituted Imidazolium Ionic Liquids 2009-06-19 doi: 10.3390/molecules14062235 Elliot Ennis Scott T. Handy http://www.mdpi.com/1420-3049/14/6/2127/ The retention behaviour of four active compounds from Sophora Flavescens Ait using three ionic liquids as mobile phase modifiers was examined. The effect of the pH and the amount of ionic liquid modifier on the retention of these compounds was determined in methanol/water (v/v) as the mobile phase containing different ionic liquids ranging in concentration from 0.1 mmol/L to 3.0 mmol/L. The ionic liquids showed promise as additives in high-performance liquid chromatography. http://www.mdpi.com/1420-3049/14/6/2127/ Thu, 11 Jun 2009 00:00:00 CEST Molecules 2009-06-11 14 6 Article 2127 2134 1420-3049 Effect of Ionic Liquids as the Mobile Phase Additives on the HPLC Resolution of Four Active Compounds from Sophora flavescens Ait 2009-06-11 doi: 10.3390/molecules14062127 Minglei Tian Junyu Liu Kyung Ho Row http://www.mdpi.com/1420-3049/14/5/1840/ Several new acyclic ammonium-TFSI ionic liquids with an allyl substituent(s) were synthesized and their physicochemical and electrochemical properties were characterized. [AAMM]Am-TFSI (3) with two allyl groups showed the widest electrochemical stability window (5.9 V) among the ammonium-based ILs reported to date because of the increment of both the anodic and cathodic limits. The charge-discharge performance of a LiCoO2-based half-cell containing [AAMM]Am-TFSI as an electrolyte was better in cycleability (the capacity retention ratio: 99% after 20 cycles) than that of the cell with the corresponding partially saturated analogue, [AMMP]Am-TFSI (2) (the capacity retention ratio: 92% after 20 cycles). http://www.mdpi.com/1420-3049/14/5/1840/ Fri, 15 May 2009 00:00:00 CEST Molecules 2009-05-15 14 5 Article 1840 1851 1420-3049 Synthesis and Properties of Acyclic Ammonium-based Ionic Liquids with Allyl Substituents as Electrolytes 2009-05-15 doi: 10.3390/molecules14051840 Taeeun Yim Chang Young Choi Junyoung Mun Seung M. Oh Young Gyu Kim http://www.mdpi.com/1420-3049/14/5/1781/ Thenanofiltration of aqueous solutions of the ionic liquids (ILs) 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4), and 1-butyl-3-methylimidazolium bromide ([Bmim]Br) with a polyamide nanofiltration membrane was investigated. The practical transport coefficients, including hydrodynamic permeability (Lp), reflection (σ) and solute permeability (ω) were calculated in terms of a non-equilibrium thermodynamics approach. It was found that Lp and σ diminished as the concentration of the IL solutions increased. These characteristics are similar to those observed in inorganic electrolyte-water systems. In addition, it was shown that the rejection and volume flux for both ionic liquid solutions rose with feed pressure, while it decreased with feed concentration. The maximum rejection efficiencies for [Bmim]Br and [Bmim]BF4 are 67 % and 60 %, respectively, on our experimental scale. All the data suggests that a highly efficient process for IL separation could be developed when the operating conditions are optimized further. http://www.mdpi.com/1420-3049/14/5/1781/ Mon, 11 May 2009 00:00:00 CEST Molecules 2009-05-11 14 5 Article 1781 1788 1420-3049 Non-Equilibrium Thermodynamic Analysis of Transport Properties in the Nanofiltration of Ionic Liquid-Water Solutions 2009-05-11 doi: 10.3390/molecules14051781 Bo Wu Yu M. Zhang Hua P. Wang