Potential Of Ionic Liquids Research Articles

Ionic Liquids and its Potential as a New Green Solvent for REE Extraction in Philippine Bauxite Residues

Abstract Rare earth elements (REEs) have become necessary for high-technology applications. This has prompted an increase in demand for REE exploration, production, and extraction. Despite its name, REEs are fairly rich in the Earth’s crust. REEs are estimated to have a crustal abundance of 9.2 ppm relative to other elements in our crust. In the Philippines, deposits are found to give adequately high concentrations of REE, ranging from approximately 200 ppm to 600 ppm. Samar bauxite deposits especially had around 500 ppm REE. In line with the planned bauxite production in the Philippines, it is of interest to further uncover ways to maximize its recovery. One of the possible optimizations in its extraction is to utilize its residue. There have been a number of methods to extract REE in bauxite residues. The use of ionic liquids (IL) to recover REE in bauxite offers a possibility of an effective and environmentally safe recovery process. ILs are molten salts that have melting points below 100degC. They exhibit high electrochemical stability, non-flammability, non-volatility, and can be tailored to the desired application. Hence, they have been the topic of study for different research regarding REE extraction in bauxite residues. Herein, the potential of ILs as a green solvent for REE extraction in bauxite is reviewed for future use in the extractive metallurgy of bauxites in the Philippines.

Potential of ionic liquids as emerging green solvent for the pretreatment of lignocellulosic biomass.

Lignocellulosic biomass is available in abundance as a renewable resource, but the major portion of it is often discarded as waste without utilizing its immense potential as an alternative renewable energy resource. To overcome recalcitrance of lignocellulosic biomass, various pretreatment methods are applied to it, so that the complex and rigid polymeric structure can be broken down into fractions susceptible for enzymatic hydrolysis. Effective and efficient biomass processing is the goal of pretreatment methods, but none of the explored pretreatment methods are versatile enough to fulfil the requirement of biomass processing with greater flexibility in terms of operational cost and desired output efficiency. Deployment of green solvents such as ionic liquids for the pretreatment of lignocellulosic biomass has been a topic of discussion amongst the scientific community in recent times. The presented work provides a detailed overview on the deployment of ionic liquid for the pretreatment of lignocellulosic biomass coupled with a brief discussion on other pretreatments methods. The recyclability and reusability along with other unique properties makes an ionic liquid pretreatment different from the other traditional pretreatment methods. Also, this study explores diverse critical parameters that governs the dissolution process of biomass. Hazardous properties of ionic liquids have also been explored. Future perspective and recommendations have been given for an efficient, effective, and eco-friendly deployment of ionic liquid in biomass pretreatment process.

Ionic Liquids as Biocompatible Antibacterial Agents: A Case Study on Structure-Related Bioactivity on Escherichia coli.

The potential of ionic liquids (ILs) to be used as antimicrobial agents for biomedical applications has been hindered by the fact that most of them are cytotoxic toward mammalian cells. Understanding the mechanism of bacterial and mammalian cellular damage of ILs is key to their safety design. In this work, we evaluate the antimicrobial activity and mode of action of several ILs with varying anions and cations toward the clinically relevant Gram-negative Escherichia coli. Langmuir monolayer technique was used to evaluate if the IL's mode of action was related to the bacterial cell membrane interaction for an effective E. coli killing. 1-Decyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [DMIM][TFSI] and trihexyltetradecyl phosphonium bis(trifluoromethylsulfonyl) imide [P6,6,6,14][TFSI] were surface-active and induced bacterial cell lysis, through a membrane-disruption phenomenon on bacteria, in a mechanism that was clearly related to the long alkyl chains of the cation. 1-Ethyl-3-methylimidazolium hydrogen sulfate [EMIM][HSO4] was highly antimicrobial toward E. coli and found suitable for biological applications since it was harmless to mammalian cells at most of the tested concentrations. The results suggest that the imidazolium cation of the ILs is mostly responsible not only for their antimicrobial activity but also for their cytotoxicity, and the inclusion of different anions may tailor the ILs' biocompatibility without losing the capacity to kill bacteria, as is the case of [EMIM][HSO4]. Importantly, this IL was found to be highly antimicrobial even when incorporated in a polymeric matrix.

Applying ionic liquids as oil additives for gearboxes: Going beyond the state of the art by bridging the nano-scale and component level

Ionic liquids (ILs) have been used effectively in many applications for reducing problems related to friction and wear. In this work, the potential of ILs as an anti-wear and extreme pressure lubricant additive for high load-carrying gearbox applications such as helicopter transmissions has been studied. Two halide-free ILs: {{rm{P}}_{8881}}{left({{rm{BuO}}} right)_2}{rm{PO}}_2^ - (1) and {{rm{P}}_{8881}}{left({{rm{MeO}}} right)_2}{rm{PO}}_2^ - (2), which are blended at 5 wt% each into a standard non-additivated FVA2 base oil (BO) are examined. Their solid—liquid interface, friction and load-carrying capacity, and wear (scuffing) behavior are studied on the nano-, lab-, and component-scale, respectively, at a different range of temperature and loading conditions by using the atomic force microscopy (AFM), Schwing—Reib—Verschleiß (SRV) friction tests, and Brugger tests, as well as forschungsstelle für zahnräder und getriebebau (FZG) back-to-back gear test rig. The AFM analysis shows nearly no change of adhesion over the full range of studied temperature for the IL blends compared to the BO. Similarly, IL blends demonstrate a very stable coefficient of friction (COF) of around 0.16, which even decreases with increasing test temperatures ranging from 40 to 120 °C. A clear reduction in COF up to 25% is achieved by adding only 5 wt% of the investigated ILs in the BO, and the Brugger tests also show a pronounced enhancement of load-carrying capacity. Finally, on the component-scale, a significant improvement in gear scuffing performance has been observed for both used IL blends. A detailed characterization of the wear tracks from the SRV friction tests via the transmission electron microscopy (TEM) revealed the formation of a phosphate (P—O)-based amorphous tribo-chemical layer of about 20 nm thickness. Therefore, this work may present an approach for ILs to be used as an additive in conventional lubricants due to their ability to enhance the lubrication properties, making them an alternative lubricant solution for high load-carrying gearbox applications.

Ionic liquid-mediated skin technologies: Recent advances and prospects

• Ionic liquid (IL) mediated technologies for topical and transdermal applications is gaining momentum. • Advance medical strategies have started using ILs for wound healing, sterilisation and other antibacterial applications. • Potency of IL in future innovative processes include vaccine delivery and insulin patches for transdermal delivery. The use of ionic liquids (ILs) in the health care sector has leveraged many existing methodologies. Their unique property of tunability has added new dimensions to conventional therapies. Skin-related applications of ILs find a large area of potential research, which can be continued with advances in the generation of newer type of ILs in the coming future. Transdermal drug delivery using ILs is a promising area that requires extensive studies to be implemented for effective strategies. These may include designing multifunctional ILs which could deliver drug molecules like proteins, peptides, and siRNAs. Recently, the potential of ILs as antimicrobials and their role in preventing biofilm formation has been discovered. An extension of this property has been to use them in wound healing applications. Interesting findings have been made with ILs used in combination with both natural and synthetic polymers. ILs also hold a bright future in exploration of other possibilities such as vaccine and insulin delivery. The review thus encompasses the latest developments in the field of ILs applied for skin-associated research.

Prospects and insights of protic ionic liquids: The new generation solvents used in fuel cells

The environmental pollution caused by rapid industrialization has augmented for several decades and there is a communal anticipation to design maintainable chemical processes so that fewer toxic materials are generated. Recently ionic liquids and its derived systems are projected as alternatives for traditional solvents because of their clean, effective and environment friendly nature. This class of solvents are tagged as ‘’designer solvents’’ due to their tunable nature and incomparable properties. The potential of ionic liquids has expanded in terms publications, so this review is devoted to a subclass of ionic liquids i.e., protic ionic liquids (PILs) with a special stress on their physicochemical properties like high thermal, electrochemical and ionic conductivity. Protic ionic liquids serve as perfect electrolytes and exhibit proton conductivity as well as activity in fuel cell electrode reactions. The good electrolytic behavior facilitates proton transport in non-aqueous condition which is one of the vital requirements in proton exchange membrane fuel cell. To exhibit better thermal stability the PIL based fuel cell electrolyte should have ΔpKa greater than 15 since the open circuit voltage displays maximum ΔpKa in the range of 16–18. PILs offer to be promising candidate for fuel cell applications and greatly enables the use of renewable energy sources.

Ionic Liquid Assessment as Suitable Solvent for Biogas Upgrading Technology Based on the Process System Engineering Perspective

AbstractBiogas requires specific processing in terms of upgradation to remove acid gas contents, making it a profitable fuel with higher energy content. This is conventionally attained through physical or chemical absorption due to the higher selectivity towards CO2 and H2S. The conventional processing technology impacts the process with higher energy content for solvent regeneration, solvent loss causing a threat to the environment with its toxicity, and damaging the equipment by corrosion. In this view, ionic liquids (ILs) emerged as potential candidates providing a favorable facet in terms of both processing and ecological aspects. Hence, herein the potential of IL and deep eutectic solvent (DES) in comparison to the conventional solvents and technologies used for biogas upgrading based on process system engineering perspective that showcases techno‐economic, energy‐economic, and environmental aspects and opportunities that may lead towards establishing sustainable and effective processing of biogas is shown and a comprehensive review on the opportunities, prospects, and challenges to make IL and DES as future solvent for biogas upgrading on the commercial scale is provided.

Unraveling weak interactions between fluorinated gases and ionic liquids

The efficient capture of fluorinated gases (F-gases) such as hexafluoroethane (R116) and 1,1,1,2-tetrafluoroethane (R134a) is critical owing to the high global warming potential of these species. Considering the potential of ionic liquids (ILs), especially fluorinated ILs (FILs), for capturing F-gases, in this study we systematically investigated the structure–property relationship between thermodynamic behaviors and weak interactions in F-gas/FIL systems. We focused on two cations, 1-octyl-3-methylimidazolium ([OMIM]+) and 1-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)-3-methylimidazolium ([FOMIM]+), and two anions, bis(trifluoromethylsulfonyl)amide ([Tf2N]−) and bis(pentafluoroethylsulfonyl)amide ([BETI]−). The effects of the IL structure on the gas–liquid equilibrium (GLE) of F-gas/FIL systems were elucidated by analyzing the experimental solubility data. The results indicate that while both the fluorinated cation and anion can enhance the solubility of F-gases, the contribution of the fluorinated cation to the increase in solubility is larger than that of the fluorinated anion. The relationship between GLE behavior and weak interactions of F-gas/FIL systems was determined by performing quantum chemical calculations.

Ionic Liquid Functionalised Nanoparticles Based Tanning System as a Less Chrome Tanning Approach

Nanoparticles due to their size and high reactivity towards collagen provide potential applications in the tanning process. The current study aims to investigate the potential of ionic liquid functionalized cerium oxide nanoparticles as a combination tanning agent with minimum utilization of the chromium. The experimental results indicate that the presence of nanoparticles increases the thermal stability from 62°C to 92°C. The physical strength and organoleptic characteristics of the nanoparticles-BCS tanned leather are on par with conventional chrome tanned leather. Antibacterial studies reveal that the leather tanned with nanoparticles shows improved antibacterial activity. Thus, nanoparticle based tanning system invokes a considerable array of interest as an alternative tanning process with minimal and efficient usage of chromium.

The potential of ionic liquids in biopharmaceutical engineering

• General criterions for ILs in biopharmaceutical applications are discussed. • Stabilization roles and mechanisms of ILs in biopharmaceuticals are described. • Application of ILs in transdermal and oral delivery of biopharmaceuticals are summarized. • Potential applications of ILs in the design of vaccine adjuvants are prospected. • Challenges of ILs in biopharmaceutical engineering are discussed. Biopharmaceuticals, such as proteins, peptides, nucleic acids and vaccines, bring about great hopes for the prevention and treatment of various diseases, but the industrialization of these products still faces challenges such as structural instability, inefficient bioactivity and low bioavailability. Ionic liquids (ILs), the marvelous solvent media with inimitable and tunable properties, may provide alternative solutions to overcome the above problems of biopharmaceutical industry. Progress has gradually been made through studies by combination of ILs with biomacromolecules. The applications involved the stabilization, protection, and delivery of biopharmaceuticals. Recent trends are being forwarded to using ILs in vaccines and nucleic acid drugs. However, challenges remain on the toxicity and safety issues. Besides, the cost of adding ILs to the benefits of biopharmaceuticals need to be considered.

Non‐Conventional Media as Strategy to Overcome the Solvent Dilemma in Chemoenzymatic Tandem Catalysis

AbstractThe amazing potential of multi‐catalytic cascade reactions to reduce the number of reaction steps and to solve synthetic problems brings the challenge of an increasing complexity that must be controlled. Particularly chemo‐enzymatic reactions are prone to conflicts regarding different optimal reaction conditions for chemical and biological catalysts. The preference of many chemical catalysts for hydrophobic (and often water‐free) solvent and of many enzymes for water poses a solvent dilemma. Recently, non‐conventional solvents have been very successful to provide suitable reaction media for catalysts that otherwise require very different solvents, and to alleviate fundamental problems such as the low solubility of many substrates in aqueous solvents. In the last few years, several examples underlined the considerable potential of ionic liquids and deep eutectic solvents for the engineering of cascade reactions. This mini‐review showcases the recent developments on the implementation of the so‐called non‐conventional media in such processes.

A Review on the Partial and Complete Dissolution and Fractionation of Wood and Lignocelluloses Using Imidazolium Ionic Liquids.

Ionic liquids have shown great potential in the last two decades as solvents, catalysts, reaction media, additives, lubricants, and in many applications such as electrochemical systems, hydrometallurgy, chromatography, CO2 capture, etc. As solvents, the unlimited combinations of cations and anions have given ionic liquids a remarkably wide range of solvation power covering a variety of organic and inorganic materials. Ionic liquids are also considered “green” solvents due to their negligible vapor pressure, which means no emission of volatile organic compounds. Due to these interesting properties, ionic liquids have been explored as promising solvents for the dissolution and fractionation of wood and cellulose for biofuel production, pulping, extraction of nanocellulose, and for processing all-wood and all-cellulose composites. This review describes, at first, the potential of ionic liquids and the impact of the cation/anion combination on their physiochemical properties and on their solvation power and selectivity to wood polymers. It also elaborates on how the dissolution conditions influence these parameters. It then discusses the different approaches, which are followed for the homogeneous and heterogeneous dissolution and fractionation of wood and cellulose using ionic liquids and categorize them based on the target application. It finally highlights the challenges of using ionic liquids for wood and cellulose dissolution and processing, including side reactions, viscosity, recyclability, and price.

Ionic Liquid Electrolytes for Metal-Air Batteries: Interactions between O2, Zn2+ and H2O Impurities

Motivated by the potential of ionic liquids (ILs) to replace traditional aqueous electrolytes in Zn-air batteries, we investigated the effects arising from mutual interactions between O2 and Zn(TFSI)2 as well as the influence of H2O impurities in the oxygen reduction/oxygen evolution reaction (ORR/OER) and in Zn deposition/dissolution on a glassy carbon (GC) electrode in the ionic liquid N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)-imide (BMP-TFSI) by differential electrochemical mass spectrometry. This allowed us to determine the number of electrons transferred per reduced/evolved O2 molecule. In O2 saturated neat BMP-TFSI the ORR and OER were found to be reversible, in Zn2+ containing IL Zn deposition/stripping proceeds reversibly as well. Simultaneous addition of O2 and Zn2+ suppresses Zn metal deposition, instead ZnO2 is formed in the ORR, which is reversible only after excursions to very negative potentials (−1.4 V). The addition of water leads to an enhancement of all processes described above, which is at least partly explained by a higher mobility of O2 and Zn2+ in the water containing electrolytes. Consequences for the operation of Zn-air batteries in these electrolytes are discussed.

Does choline-based amino acid ionic liquid behave as a biocompatible solvent for stem bromelain structure?

Abstract The potential of ionic liquids (ILs) as green solvent has opened burgeoning new areas of its application in various scientific and engineering fields. However, all ILs cannot be considered as “green solvent” due to toxicity and biodegradability issues associated with them. Therefore, the need of the hour is to synthesize green ILs in which efforts should be made to include cations and anions of the ILs from biological source. In this regard, choline glycine ([Ch][Gly]) has been synthesized in which both the ions belong to the bio-available sources. The stability and activity of stem bromelain (BM) have been studied in presence of choline bromide ([Ch][Br]) and [Ch][Gly]. The comparison of activity and stability of BM in both ILs have been performed using spectroscopic techniques and size parameter has been assessed using dynamic light scattering (DLS). On contrary to our expectation [Ch][Gly] proved to be a poor stabilizer for the BM when compared to [Ch][Br]. This can be due to the fact that in case of [Ch][Gly], Glycinate anions are forming strong H-bonds with the enzyme polypeptide backbone which dissociate the H-bonds that maintain the structural integrity of protein, while no such kind of interaction is present in case of [Ch][Br].

Emerging Corrosion Inhibitors for Interfacial Coating

Corrosion is a deterioration of a metal due to reaction with environment. The use of corrosion inhibitors is one of the most effective ways of protecting metal surfaces against corrosion. Their effectiveness is related to the chemical composition, their molecular structures and affinities for adsorption on the metal surface. This review focuses on the potential of ionic liquid, polyionic liquid (PIL) and graphene as promising corrosion inhibitors in emerging coatings due to their remarkable properties and various embedment or fabrication strategies. The review begins with a precise description of the synthesis, characterization and structure-property-performance relationship of such inhibitors for anti-corrosion coatings. It establishes a platform for the formation of new generation of PIL based coatings and shows that PIL corrosion inhibitors with various heteroatoms in different form can be employed for corrosion protection with higher barrier properties and protection of metal surface. However, such study is still in its infancy and there is significant scope to further develop new structures of PIL based corrosion inhibitors and coatings and study their behaviour in protection of metals. Besides, it is identified that the combination of ionic liquid, PIL and graphene could possibly contribute to the development of the ultimate corrosion inhibitor based coating.

Ionic liquids as heat transfer fluids – An assessment using industrial exchanger geometries

The objective of this work is to carry out a practical assessment of using a typical ionic liquid as a heat transfer fluid. In order to carry out such an assessment, the thermophysical properties, namely, density, heat capacity, viscosity, and thermal conductivity need to be known for the chosen ionic liquid. A typical ionic liquid chosen for the current study is 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide, ([bmim][Tf2N]) based on the availability of thermophysical properties over a range of temperatures. The assessment was carried out by simulating the heat transfer characteristics for this ionic liquid in two different types of heat exchangers, namely, a plate heat exchanger and a shell and tube heat exchanger. The results of the heat transfer behavior for the ionic liquid in these two exchanger types are described. These results are also compared with the results for a conventional industry standard heat transfer fluid. It is demonstrated that although the heat transfer characteristics, in terms of heat transfer coefficient, for the chosen ionic liquid are not particularly attractive, it is possible to obtain reasonable heat transfer coefficients by judicious selection of heat exchanger type, heat exchanger configuration and possible use of heat transfer enhancement technology. Finally conclusions are drawn about the potential of ionic liquids as heat transfer fluids taking into account the heat transfer assessment as well as a number of other practical considerations.From a practical perspective the paper reflects a typical work flow used by a practicing thermal engineer when heat transfer performance characteristics for a given fluid or a given heat exchanger type are to be assessed, with a view of optimizing the overall equipment or system performance.

Biomimetic Catalysis in Ionic Liquids: Markedly Enhanced Enantioselectivity in Amino Acid-Catalyzed Directed Asymmetric Aldol Reactions

AbstractAmino acid-catalyzed directed asymmetric aldol reactions showed enhanced enantioselectivity when conducted in ionicliquids. Optically active products were afforded in better yields (up to 23% higher) and enantiomeric excess (up to 21%higher) in ionic liquids than in conventional organic solvents.Keywords: Ionid Liquid, Aldol Reaction, Amino Acid, Catalysis 1. Introduction Room-temperature ionic liquids are attracting grow-ing interest as alternative reaction media for chemicaltransformations [1-2] . One major advantage of ionic liq-uids is that they have no detectable vapor pressure,making them environmentally benign. Hence, they areemerging as novel replacements for volatile organic sol-vents in industrial organic synthesis. Room-temperatureionic liquids are particularly promising as solvents forcatalysis, allowing enhanced catalyst activity, selectiv-ity, stability, and reusability. Research in this area hasso far focused on transition metal-catalyzed transforma-tions. Recently, research groups, including ours, havereported on the potential of ionic liquids as alternativereaction media for biocatalysis and biotransformation

The potential of ionic liquids for CO2capture

The potential of ionic liquids for CO2capture

Influence of Chemical Structure on the Solubility of Low Molecular Weight Carbohydrates in Room Temperature Ionic Liquids

The use of room temperature ionic liquids (ILs) as green solvents is an emerging and innovative technology, which is quickly expanding in carbohydrate chemistry. However, information about solubility of low molecular weight carbohydrates (LMWC) in ILs is still scarce. This study provides new solubility data for several LMWC dissolved in methylimidazolium-based ILs. Different solubility values have been obtained for carbohydrates depending on their structure. In general, ketoses are more soluble than their corresponding aldoses, and trisaccharides are more soluble than mono- and disaccharides, although some exceptions have been observed depending on the tested IL. [BMIM][MeSO4] and [HMIM][Cl] acted both as solvent and as catalyst for dehydration of ketoses (fructose and tagatose) into 5-hydroxymethylfurfural at 318 K. These findings pointed out the potential of ILs as an interesting alternative solvent for new applications in applied carbohydrate chemistry.

Biogrowth of <i>Escherichia coli</i> in Bio-Ionic Media

The impact of development of ionic liquids (ILs) in biochemical appliances has attracted attention from many researchers to further investigate on the potential of ILs. Use of ILs has provided an effective alternative in the conversion of source of carbohydrate in woody plant into fermentable sugar for ethanol production. To investigate how the presence of ILs affects the fermentation process, fermentation by using E. coli were conducted in different fermentation conditions with the presence of ILs. The purpose of this research is to investigate microbial growth under the presence of ILs with various parameters. Ability of E. coli to grow in facultative condition has made these bacteria suitable for this research. In this research, the growths of E. coli in the presence of ILs were observed by shaken culture method for 24 hours. The E. coli was tested to grow in 5 % v/v [0.005, 20 % v/v [0.02, and 50 % v/v [0.05 of IL concentration ratios. The three types of ILs used for this research were 1-Ethyl-3-methylimidazolium Acetate [EMIM][A, 1-Butyl-3-methylimidazolium Chloride [BMIM][Cl] and 1-Allyl-3-methylimidazolium Chloride [AMIM][Cl]. The growth patterns of E. coli were also observed during the fermentation with shaking frequency of 250 rpm, 300 rpm and 350 rpm.