Use Of Ionic Liquids Research Articles

(Physical and Analytical Electrochemistry Division Max Bredig Award In Molten Salt and Ionic Liquid Chemistry) Of Ionic Liquids and Hydrogen Bonds

Whether it is the solubility of biopolymers, the rates of reactions, the physical properties of ionic liquids, or the formation of Deep Eutectic Solvents, the concept of the hydrogen bond often finds itself at the centre of explanations of ionic liquids’ behaviours. How strange it would seem to someone entering the field today that the idea that hydrogen bonds could form in ionic liquids was even recently controversial. So, how did this transformation come about?In this presentation, you will meet some of the most well-known names in ionic liquids, both past and present. Key insights have only come from a variety of different techniques, both experimental and theoretical, being brought to bear on the question of whether hydrogen bonds exist or are of any use in ionic liquids and their solutions. You will also see that opposing views can turn out to both be correct and controversies are not always solved by one side ‘winning’ over the other.

The Impact of Phase Changes of Imidazolium Based Ionic Liquids on the Solubility of Hydrofluorocarbons

Project EARTH (Environmentally Applied Research Toward Hydrofluorocarbons) is focused on developing sustainable processes for selectively separating refrigerant mixtures with high global warming potentials. The initial focus of the project is R-410A which is widely used in both commercial refrigeration systems and residential air conditioning. It is an azeotropic mixture containing 50 wt.% HFC-32 (CH2F2) and 50 wt.% HFC-125 (CHF2CF3). The separation approaches being investigated include membranes, porous media, and the use of ionic liquids as entrainers for extractive distillation.This poster will describe the work being conducted using ionic liquids and will specifically focus on the impact of phase changes of imidazolium based ionic liquids that are solid at room temperature on the solubility of HFC-32 and HFC-125. The poster will include an overview of how we use specialized equipment including a High-Pressure View Cell and Hiden Isochema IGA gravimetric microbalance to build a comprehensive understanding of these solubility differences.

Beckmann Rearrangement with Improved Atom Economy, Catalyzed by Inexpensive, Reusable, Bro̷nsted Acidic Ionic Liquid

Inexpensive protic ionic liquids, synthesized from di- or triamines and excess sulfuric acid, were used as solvents and catalysts for the Beckmann rearrangement. The use of ionic liquids in place of oleum or sulfuric acid allowed the base neutralization step, which is required in the conventional Beckmann rearrangement, to be entirely avoided, thereby dramatically improving the atom economy. Using a biphasic water/organic solvent extraction system, it was possible to recover and reuse the ionic liquid. The proposed method was found applicable for the synthesis of a range of primary and secondary amides.

Chemical hydrolysis of hemicellulose from sugarcane bagasse. A comparison between the classical sulfuric acid method with the acidic ionic liquid 1-ethyl-3-methylimidazolium hydrogen sulfate

Dilute sulfuric acid and acidic ionic liquids are pretreatment methods used to selectively hydrolyze hemicellulose from lignocellulosic biomasses. In this work, a comparison between these techniques is carried out by treating sugarcane bagasse both with 1-ethyl-3-methylimidazolium hydrogen sulfate at different ionic-liquid and water contents and with H 2 SO 4 at the same conditions and equivalent ionic liquid molar contents. Results from the use of ionic liquid showed that it was possible to tune the biomass treatment either to achieve high hemicellulose hydrolysis yields of 72.5 mol% to very low furan and glucose co-production, or to obtain furfural at moderate yields of 18.7 mol% under conditions of low water concentration. In comparison to the use of ionic liquid, sulfuric acid pretreatment increased hemicellulose hydrolysis yields by 17%, but the 8.6 mol% furfural yield was also higher, and these yields were obtained at high water concentration conditions. Besides, no such tuning ability of the biomass treatment conditions can be made.

SYNTHESIS AND GROWTH-STIMULATING ACTIVITY OF TRIMECAINE ETHYL IODOETHANOATE

Novel activation methods such as ultrasonic activation and microwave irradiation are becoming increasingly popular in the green synthesis of ionic liquids and ionic compounds. The use of ionic liquids and ionic compounds is becoming more and more interesting for scientists precisely because of their growth-stimulating activity.The purpose.Synthesisof trimecaine ethyl iodoethanoatewascarried out via N-alkylation in classical conditions and using ultrasonicirradiation and microwave-assisted synthesis. Methodology.Thestructure and functional groups of novel synthesized substanceidentifiedby1H,13C NMRandIR,and growth-stimulating activity tested fortengenotypes of sweet sorghum seeds.Thesynthesis of trimecaine ethyliodoethanoate was carried out via N-alkylation in classical conditions and using microwave radiation and ultrasonic activation. Results.The synthesized ionic compoundswere characterized by IR, 1H and 13C NMR, growth-stimulating activity was tested on ten varieties and hybrids of sweet sorghum seeds. Alternative methods for the synthesis of ultrasonic and MW activation showed a good result in the synthesis of N,N-diethyl-N-ethylethanoate-N-(2-(mesitylamino)-2-oxoethyl)aminium iodide with a higher isolation yield in a shorter time compared to classical conditions. Conclusion.The product with the highest yield is formed under MW irradiation in a short time, while under classical conditions the yield was lower, and the reaction time was longer. The synthesized ionic compound had a better effect on the energy and germination of all types of sweet sorghum seeds compared to the control.

Condensation Reactions of Aromatic Aldehydes with Active Methylene Compounds: The Beneficial Sinergy of Alkaline Ionic Liquid in One Pot Synthesis

Background: In recent times, there has been on-going interest in developing convenient and environmentally friendly synthetic methods in organic chemistry. The use of ionic liquid catalysts in organic synthesis is a developing area that allows reactions to be run at low temperatures and without solvents. Literature overview revealed that room temperature supported ionic liquid catalysis is a developing field in catalytic science with huge application in organic synthesis. Hence in this current article, our focus is on the one-pot synthesis of arylidene derivatives with the use of ([bmim] OH) ionic liquid. Objectives: We describe here the use of an ionic liquid catalyst, 1-n-butyl-3-methylimidazolium hydroxide, [bmim] OH), in the convenient one pot synthesis of arylidene derivatives by the reaction of the active methylene compound, malononitrile, with pyrazole aromatic aldehydes under microwave irradiation. Methods: The functionalized ionic liquid, 1-n-butyl-3-methylimidazolium hydroxide ([bmim] OH), catalyzed Knoevenagel condensation reactions of pyrazole aromatic aldehydes with active methylene compound malononitrile carried out under microwave irradiation. The reaction progress was monitored by thin layer chromatography and the synthesized compounds were further characterized by NMR spectroscopy. Results: This proposed work demonstrates the utility of the use of the ionic liquid catalyst [bmim] OH, in the suitable, high yield (80-95%) microwave assisted reactions of pyrazole aromatic aldehydes with the active methylene compound, malononitrile. Conclusion: An eco-friendly synthesis of pyrazole derivatives has been demonstrated using ([bmim] OH) ionic liquid as a catalyst for the Knoevenagel condensation reactions of pyrazole aromatic aldehydes and malononitrile with microwave irradiation. The advantages of this green method are its convenience, mild reaction conditions, and high product yields (80-95%).

Effect of Iodide-Based Organic Salts and Ionic Liquid Additives in Dye-Sensitized Solar Cell Performance.

The use of ionic liquid and organic salts as additives for electrolyte systems in dye-sensitized solar cells have been widely described in recent years. The tunability of their physical-chemical properties according to the cation–anion selection contributes toward their high efficiencies. For this purpose, several iodide-based organic salts including imidazolium, picolinium, guanidinium and alkylammonium cations were tested using acetonitrile/valeronitrile electrolytes and their photovoltaic parameters were compared. A best efficiency of 4.48% (4.15% for the reference) was found for 1-ethyl-2,3-dimethylimidazolium iodide ([C2DMIM]I) containing electrolyte, reaffirming the effectiveness of these additives. 4-tertbutylpyridine was included into the formulation to further improve the performance while determining which iodide salts demonstrate the highest synergy with this additive. [C2DMIM]I once again proved to be the superior additive, achieving an efficiency of 6.48% (6% for the reference). Electrochemical impedance spectroscopy was employed to elucidate the effects of the various additives, demonstrating the relevance of the counter electrode resistance on device performance. Finally, several computational descriptors for the cationic structures were calculated and correlated with the photovoltaic and resistance parameters, showing that properties related to polarity, namely relative positive charge, molecular polarizability and partition coefficient are in good agreement with the counter-electrode resistance.

Recent applications of ionic liquid-based tags in glycoscience

The functionalization of glycosides with ionic compounds such as ionic liquids provides enhanced polarity for the labelled glycans thanks to the presence of a permanent positive charge. The chemical derivatisation of glycans with ionic liquids constitutes an emerging strategy to boost the detection sensitivity in MS applications. This allows the straightforward monitoring and detection of the presence of labelled glycans in complex matrices and in those cases where very limited amounts of material were available such as in biological samples and chemoenzymatic reactions. The use of ionic liquid based derivatisation agents can be further exploited for the labelling of live cells via metabolic oligosaccharide engineering for the detection of cancer biomarkers and for the tuning of live cells-surface properties with implications in cancer prognosis and progression. In this mini-review we summarise the latest development of the ionic liquid based derivatisation agents in glycoscience focussing on their use for sensitive MS applications.

Liquid antisolvent crystallization of pharmaceutical compounds: current status and future perspectives.

The present work reviews the liquid antisolvent crystallization (LASC) to prepare the nanoparticle of pharmaceutical compounds to enhance their solubility, dissolution rate, and bioavailability. The application of ultrasound and additives is discussed to prepare the particles with narrow size distribution. The use of ionic liquid as an alternative to conventional organic solvent is presented. Herbal compounds, also known for low aqueous solubility and limited clinical application, have been crystalized by LASC and discussed here. The particle characteristics such as particle size and particle size distribution are interpreted in terms of supersaturation, nucleation, and growth phenomena. To overcome the disadvantage of batch crystallization, the scientific literature on continuous flow reactors is also reviewed. LASC in a microfluidic device is emerging as a promising technique. The different design of the microfluidic device and their application in LASC are discussed. The combination of the LASC technique with traditional techniques such as high-pressure homogenization and spray drying is presented. A comparison of product characteristics prepared by LASC and the supercritical CO2 antisolvent method is discussed to show that LASC is an attractive and inexpensive alternative for nanoparticle preparation. One of the major strengths of this paper is a discussion on less-explored applications of LASC in pharmaceutical research to attract the attention of future researchers.

Ionic liquid‐functionalized reinforcements in epoxy‐based composites: A systematic review

AbstractSeveral high‐performance reinforcements may be used in epoxy‐based composites. These commonly undergo chemical and/or physical treatments to enhance their interfacial interactions with polymer matrices. One recent technology comprises the use of ionic liquids (IL) as compatibilizers. This strategy may result in the development of composite materials with greater performance or multifunctional characteristics. Herein, an overview in the area of IL‐modified reinforcements and their effect on epoxy‐based composites is presented. The PRISMA protocol was followed for the review, and the focus of these studies was on the modification of carbon nanotubes, followed by graphene/graphite nanoplatelets and bio‐fillers. The most used IL were those based on imidazolium cation, especially 1‐butyl‐3‐methylimidazolium chloride. In most cases, when IL are used, the reinforcement displays stronger interactions with the epoxy matrix, depending the treatment route employed. Improved interfacial interactions are cited as the main reason for the improvement in the composite mechanical and thermal performances. It was also found that strategies for using low IL content, or routes that enable recovery of the salts after fiber/particle treatment, are still required, as well as the study of the influence of different amounts/types of IL on the structure of fillers and their relationships with the composite properties.

Oil recovery tests with ionic liquids: A review and evaluation of 1-decyl-3-methylimidazolium triflate

The main advantages of the use of ionic liquids in enhanced oil recovery are their tunability and stability in harsh environmental conditions. In this work, a comprehensive review of ionic liquids proposed to improve current chemical oil recovery methods has been presented, focusing on core flooding experiments. With an almost infinite number of possible ionic liquids, the amount of experiments carried out up to now has been very limited. However, results are promising, with additional recovery after secondary flooding of up to 32% of the original oil in place. Most formulations with ionic liquids have been proposed for sandstone reservoirs, the number of studies with carbonate cores being very scarce. The possibilities of a new room temperature surface active ionic liquid, 1-decyl-3-methylimidazolium triflate, for this application were analyzed. It was shown that it is able to drastically reduce the water/oil interfacial tension. An optimized formulation was proposed for carbonate reservoirs. After secondary flooding with brine, an additional recovery of 10.5% of original oil in place was achieved at room conditions. A combination of the proposed method followed by a polymer flooding step with polyacrylamide led to a lesser but still significant recovery, reducing the costs associated to the ionic liquid.

Adsorption, thermodynamic, and quantum chemical investigations of an ionic liquid that inhibits corrosion of carbon steel in chloride solutions

The purpose of this work lies in the use of ionic liquids as corrosion inhibitors due to the difficulty in some oil fields with the solubility of corrosion inhibitors and these materials can be miscible with water and thus provide a solution to such problems in the industry. The second purpose is concerned with the lower toxicity of these compounds compared with the most common corrosion inhibitors. The study covered the corrosion inhibition performance of the ionic liquid 1-butyl-3-methylimidazolium trifluoromethyl sulfonate ([BMIm]TfO) for carbon steel in 3.5% NaCl solutions. The study comprised electrochemical, adsorption, and quantum chemical investigations. The results manifested that [BMIm]TfO can be considered a promising corrosion inhibitor and the inhibition efficacy intensifies as the concentration rises. The observed inhibitive effect can be correlated to the adsorption of the ionic liquid species and the creation of protecting films on the surface. The mode of adsorption follows the Langmuir adsorption isotherm. The polarization results showed that the ionic liquid [BMIm]TfO functions as a mixed inhibitor. Reliance of the corrosion influence on the temperature in the existence and absence of [BMIm]TfO was demonstrated in the temperature range of 303–333 K using polarization data. Activation parameters were determined and discussed. The observed inhibition performance of [BMIm]TfO was correlated with the electronic properties of the ionic liquid using a quantum chemical study.

Deconstruction of lignocellulosic biomass for bioethanol production: Recent advances and future prospects

The total annual emission due to fossil fuel and agro waste stubble burning is 36.73 teragrams CO2 equivalent. Many international organizations focus on alternative energy sources such as biofuel production. In the recent past, biofuel production has gathered pace and increased dramatically, with the USA and Brazil topping the list for bioethanol production. Recent advancements in pre-treatment technologies include the use of ionic liquids and deep eutectic solvents. In this review, many recent advancements on pre-treatment technology of biomass have been discussed. This review also emphasizes on the recent advancements made in the field of saccharification technology. Bioethanol production from cellulosic biomass is facilitated by a complex set of enzymes mainly endoglucanase, exoglucanase and ß-glucosidase apart from other auxillary enzymes and accessory protiens. In this review, multiple approaches have been explored which enhance biofuel production such as developing cellulose degrading microbial consortia and genetically modified microbes. This study also highlights the importance of bioethanol production with reference to climate change concerns, advances in technologies and future perspectives.

Probing new DABCO-F based ionic liquids as catalyst in organic synthesis

The use of ionic liquids as an alternative to the traditional organic solvents offers many advantages, such as their (relatively) low cost of production, ease of handling and storage, high thermal stability, non-volatility, and ability to dissolve different organic and inorganic compounds. The use of ionic liquids for organic syntheses is also sustainable and environmentally friendly as they can be easily recovered and recycled after use. Herein we have synthesized 1,4-diazabicyclo[2.2.2]octane (DABCO)-based ionic liquids with fluoride anion, hence DABCO-C5-F and DABCO-C7-F, containing C5 and C7 alkyl chains respectively, were synthesized and characterized. Thermal studies (TGA/DSC) were also carried out to find out the decomposition temperature (and hence the working temperature range) of the ionic liquids. Moreover, quantum mechanical calculations were performed to obtain the optimized geometry configuration of ionic liquids and their stability was evaluated via binding energy calculation obtained from the MP2 method on the optimized structures. Finally, the DABCO ionic liquids were investigated for their efficiency for the synthesis of different organic compounds (indoles and 1,4-dihydropyridines), which were prepared in good to excellent yields indicating that these DABCO-F can be successfully utilized in organic syntheses by their dual role as ionic liquid and as a catalyst.

Recent Developments in Ionic Liquid-Assisted Topical and Transdermal Drug Delivery

Ionic liquids (ILs) have attracted growing interest as designer solvents/materials for exploring unrealized functions in many areas of research including drug formulations and delivery owing to their inherent tunable physicochemical and biological properties. The use of ILs in the pharmaceutical industry can address challenges related to the use of conventional organic solvent-based chemical permeation enhancers. Their tunability in forming ion pairs with a diverse range of ions enables the task-specific optimization of ILs at the molecular level. In particular, ILs comprising second- and third-generation cations and anions have been extensively used to design biocompatible drug delivery systems to address the challenges related to conventional topical and transdermal drug delivery, including limited permeability, high cytotoxicity, and skin irritation. This review highlights the progress in IL-related research with particular emphasis on the very recent conceptual developments in transdermal drug delivery. Technological advancement and approaches for the formation of IL-based topical and transdermal delivery systems, as well as their promising application in drug delivery, are also discussed.

Ionic Liquid and Ionanofluid-Based Redox Flow Batteries—A Mini Review

Stationary energy storage methods such as flow batteries are one of the best options to integrate with smart power grids. Though electrochemical energy storage using flow battery technologies has been successfully demonstrated since the 1970s, the introduction of ionic liquids into the field of energy storage introduces new dimensions in this field. This reliable energy storage technology can provide significantly more flexibility when incorporated with the synergic effects of ionic liquids. This mini-review enumerates the present trends in redox flow battery designs and the use of ionic liquids as electrolytes, membranes, redox couples, etc. explored in these designs. This review specifically intends to provide an overview of the research prospects of ionic liquids for redox flow batteries (RFB).

Solvent Extraction of Metal Ions from Synthetic Copper Leaching Solution Using R4NCy

Recent works suggest that the use of ionic liquids in the copper solvent extraction industry is feasible. However, the reports did not use real solutions (or synthetic solutions with various elements). This fact remains poorly established, and the interaction efficiencies are still under study. The objective of this research is to explore the extraction and stripping of the four major elements present in a copper industrial pregnant leach solution (Cu(II), Fe(III), Mn(II), and Zn(II)) using the methyltrioctyl/decylammonium bis(2,4,4-trimethylpentyl)phosphinate (R4NCy) ionic liquid as an extractant. The work conditions studied in extraction were ionic liquid concentration, initial pH, and O/A ratio, and in stripping were H2SO4 concentration and O/A ratio. The test was carried out at room temperature and ambient pressure. High efficiency and selectivity (99.82% and 113,755 over Cu(II), respectively) were observed for Fe(III) extraction over the other elements. Moreover, after the extraction test, significant difficulty in stripping Fe(III) loaded in the ionic liquid was observed (28.7% at 0.5 M of H2SO4). Finally, the present study demonstrates that the R4NCy ionic liquid is not suitable for copper extraction because it has a higher selectivity for Fe(III) and Zn(II).

Ionic Liquid Promoted Regio‐Selective Synthesis of 2‐Methyl amino‐3‐Nitro‐pyrano[3,2‐c]chromen‐5‐ones

AbstractAn efficient, and simple protocol for the synthesis of extremely functionalized pyrano[3,2‐c]chromen‐5‐ones (4 a–v) has been developed. One‐pot multicomponent cyclo‐condensation of 4‐hydroxycoumarin, aromatic‐aldehydes, and (E)‐N‐methyl‐1‐(methylthio)‐2‐nitroethenamine (NMSM) catalyzed by ionic liquid [(EMIM)Ac] in two different methods as methanolic mediated and at solvent free condition is described which presumably involve the Knoevenagel reaction succeeding Michael‐addition and O‐cyclization with elimination of methanethiol. The noteworthy features of this protocol are use of ionic liquid as catalyst, good to excellent yield, optimum reaction time with easy experimental procedure. The prepared derivatives were characterized by IR, 1HNMR,13CNMR and HRMS spectroscopic techniques.

Biocompatible Cationic Lipoamino Acids as Counterions for Oral Administration of API-Ionic Liquids

PurposeThe use of ionic liquids (ILs) in drug delivery has focused attention on non-toxic IL counterions. Cationic lipids can be used to form ILs with weakly acidic drugs to enhance drug loading in lipid-based formulations (LBFs). However, cationic lipids are typically toxic. Here we explore the use of lipoaminoacids (LAAs) as cationic IL counterions that degrade or digest in vivo to non-toxic components.MethodsLAAs were synthesised via esterification of amino acids with fatty alcohols to produce potentially digestible cationic LAAs. The LAAs were employed to form ILs with tolfenamic acid (Tol) and the Tol ILs loaded into LBF and examined in vitro and in vivo.ResultsCationic LAAs complexed with Tol to generate lipophilic Tol ILs with high drug loading in LBFs. Assessment of the LAA under simulated digestion conditions revealed that they were susceptible to enzymatic degradation under intestinal conditions, forming biocompatible FAs and amino acids. In vitro dispersion and digestion studies of Tol ILs revealed that formulations containing digestible Tol ILs were able to maintain drug dispersion and solubilisation whilst the LAA were breaking down under digesting conditions. Finally, in vivo oral bioavailability studies demonstrated that oral delivery of a LBF containing a Tol IL comprising a digestible cationic lipid counterion was able to successfully support effective oral delivery of Tol.ConclusionsDigestible LAA cationic lipids are potential IL counterions for weakly acidic drug molecules and digest in situ to form non-toxic breakdown products.

Role of Ionic Liquids in Capillary Electrophoresis

Ionic liquids are a very important class of compounds due to their remarkable properties and wide range of applications. On the other hand, capillary electrophoresis is also gaining importance in separation science because of its fast speed and inexpensive nature. The use of ionic liquids in capillary electrophoresis is gaining importance continuously. The present review article describes the applications of ionic liquids in capillary electrophoresis. This article also describes the general aspects of ionic liquids and capillary electrophoresis. The use of ionic liquids in capillary electrophoresis, optimization of separation, mechanism of separation, and toxicity of ionic liquids, as well as their future perspectives, have also been discussed. It was observed that not much work has been performed in capillary electrophoresis using ionic liquids. It was also realized that the use of ionic liquids in capillary electrophoresis could revolutionize analytical science. Briefly, there is a great need for the use of ionic liquids in capillary electrophoresis for better and more effective separation.