Use Of Ionic Liquids Research Articles

Ionic Liquids for the Chemical Recycling of Polymeric Materials and Control of Their Solubility.

Plastics are wonderful materials that have modernized our daily life; however, importance of effective recycling of plastics is gradually recognized widely. In this account, we describe our discovery of new and efficient methods for the chemical recycling of plastics using ionic liquids (ILs). Since the chemical recycling usually requires high temperature conditions to breakdown chemical bonds in polymeric materials, we thought that less-flammability and non-volatility of ionic liquids are the most suitable physical properties for this purpose. Ionic liquids successfully depolymerized polyamides and unsaturated polyesters smoothly and corresponding monomeric materials were obtained in good yields. To the best of our knowledge, this was the first use of Ionic liquids for such reactions. However, we encountered another difficult problem-separation. To solve the problem, we developed solubility-switchable ionic liquids, a new type of ionic liquids in which solubility is readily changed using the chemistry of protective groups. Conversion between hydrophilic and lipophilic forms was readily achieved using a simple chemical treatment under mild conditions, and the complete separation of products was achieved by liquid-liquid-extraction. The robustness of either form unlocks their wide use as reaction solvents.

Effects of nickel and manganese on ductile iron utilizing ionic liquid harvested iron and Bosch byproduct carbon

To ensure the success of surface missions and the eventual habitation of the Lunar and Martian surfaces, construction materials for machine components, tools, plumbing, and more must be considered for the long-term supportability of astronauts. The financial burden of launching these materials from Earth is far too great; therefore, in-situ resource utilization (ISRU) technology will be required. The Martian environment contains numerous elements for producing bulk metal components; however, these elements are almost exclusively found as compounds. The use of ionic liquids (ILs) for elemental metal harvesting is being researched by NASA's Marshall Space Flight Center (MSFC) to extract feedstock materials from local regolith and meteorites. Studied at MSFC as a life support system, the Boschprocess produces a byproduct elemental carbon (C) during oxygen (O2) regeneration from metabolic or environmental carbon dioxide (CO2). This study details the refinement of a ductile iron (DI) designed to simulate the combination of IL-harvested iron (IL-Fe) and Bosch C by investigating the effects of Ni and Mn addition on IL-DI properties. Dilatometry was used to evaluate how the properties of the IL-DI might vary when produced in the Martian environment. DIs were cast using commercial elements with C produced via a C formation reactor (C–Fr) at MSFC with microstructural, hardness, and phase diagram analyses completed. Results suggest that the combination of IL-Fe and Bosch C could be a viable means of producing DI alloys in-situ and, with the quantities used here, the use of Ni could be more beneficial to alloy customization than Mn additions for IL-DI alloys.

A kinetics study of copper-catalysed click reactions in ionic liquids.

Copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reactions are of extensive interest in chemical synthesis. While the use of ionic liquids (ILs) as solvents for synthesis has been widely explored in recent years, the understanding of their influence on the mechanism and reactivity of CuAAC reactions remains poorly understood. Here, we investigate the kinetics of a phenylacetylene-benzylazide and acetylene-benzylazide CuAAC reaction to probe the influence of IL structure, including the role of the base used to promote the reaction and the importance of water content. The use of 'wet' ILs led to remarkable changes in the kinetic profile of the reaction by eliminating the initial induction period. The reaction rate was found to be dependent on the copper(I) source. The effect of an added base was also studied, with the use of a tertiary amine-bearing IL leading to high conversions in under 5 min at ambient temperature. The results of this study highlight the nature and complexity of CuAAC reactions in ILs. As more ILs are getting involved in industrial processes, the data obtained from this study are valuable for better understanding processes that affect the CuAAC reaction in IL media and for creating customized systems for organic synthesis, thus improving the efficiency and sustainability of such processes.

Mixture of an ionic liquid and organic solvent at graphene: interface structure and ORR mechanism.

Aprotic lithium-oxygen batteries are attracting the attention of the scientific community due to their outstanding theoretical performance, which, however, still has not been achieved in practice. One of the promising directions for improving the stability of Li-O2 batteries is electrolyte design, which would provide good cyclability, inhibition of parasitic processes, and high energy density. In recent years, there has been progress in the use of ionic liquids in the composition of the electrolyte. The present work reveals possible explanations of the influence of the ionic liquid on the mechanism of the oxygen reduction reaction by the example of a combined electrolyte from an organic solvent DME and an ionic liquid Pyr14TFSI. Molecular dynamics modelling of the interface between a graphene electrode and an organic solvent DME with a variable volume fraction of the ionic liquid shows the influence of the electrolyte structure at the interface to the kinetics on the adsorption and desorption stages of oxygen reduction reaction reactants. The obtained results suggest the promotion of a two-electron oxygen reduction reaction mechanism through the formation of solvated O22-, which may explain the reduced recharge overpotential reported in experiments.

Ionic liquids as potential electrolytes for sodium-ion batteries: an overview.

In this study, we present an overview on the use of ionic liquids (ILs) as electrolytes in sodium-ion batteries (SIBs). The development of SIBs has gained traction over the last few years because Na is cheaper and more abundant than Li. In this case, although great efforts have been devoted to finding high-capacity and high cell potential materials for SIBs, electrolyte safety is an important factor in producing more competitive and reliable devices. Specifically, the intrinsic volatility of the organic solvent-based electrolytes commonly used in commercial systems is a safety risk during the operation of batteries, and thus replacing them with ILs is an alternative that should be considered. This family of electrolytes is more thermally stable than organic solvents, but they suffer from poor transport properties. Herein, we discuss these properties, considering neat ILs, effects of cations and anions, and effect of salt concentration. Moreover, the strategies to overcome the transport limitations are highlighted. Then, the recent applications of mixtures containing sodium salts and ILs as electrolytes for the negative and positive electrodes in SIBs are presented. Finally, the use of Na-IL mixtures in solid-state electrolytes is discussed.

IONIC LIQUIDS – NEW GAS CHROMATOGRAPHIC PHASES WITH UNIQUE PROPERTIES. A REVIEW

A necessary and the most difficult element in the study of many chemical processes is a reliable chemical analysis of both the initial reagents and the products of their transformation. One of the most common methods for such analysis is a capillary gas chromatography, which, unfortunately, has a number of limitations. The limitations include, for example, the low thermal stability of high polarity stationary liquid phases (SLF). A way to overcome this limitation is the use of ionic liquids (IL) as SLF. In this review, we focus on the use of liquid phases based on ILs with cations of various chemical classes. The properties of such phases are considered from the point of view of their possible chromatographic selectivity, and examples of the use of columns with ILs for solving specific analytical problems are given. The properties of currently available commercial columns where ILs are used as the phases are discussed.

Synthesis of pyridinium-based ionic liquids and their application to improve Candida rugosa lipase stability in a methanol-water solvent system.

This paper studied the effect of pyridinium-based ionic liquids as cosolvents in a methanol-water solvent system on the hydrolytic activity of Candida rugosa lipase. These ionic liquids were successfully synthesized using imidazolium-based ionic liquid synthesizing methods with a certain adjustment. The hydrolytic activity of Candida rugosa lipase was analyzed using 4-nitrophenol acetate (pNPA) and 4-nitrophenol palmitate (pNPP) as substrates. The addition of ionic liquids had no significant effect on the hydrolytic activity of lipase in a water solvent, and it had a greater effect in methanol. The addition of [C6Py] Br ionic liquid as a methanol cosolvent (methanol: ionic liquid, 10:5) could increase the hydrolytic activity of lipase. The use of ionic liquid as a cosolvent could increase the hydrolytic activity of lipase by about 15.61% while using pNPP as a substrate in the methanol system. A molecular dynamics study for the interaction between lipase and ionic liquids supported the experimental results. The ionic liquid using bromide as an anion provided more stability on lipase conformation. It tends to form the short-range interaction between the lipase and bromide anion.

Microemulsion system formed with new piperazinium-based surface-active ionic liquid

The intensive use of ionic liquid (IL) in various researches and applications induces the imperative need of specific functional ILs. Present work introduces a novel piperazinium-based surface-active IL (SAIL) which shows great potential for the preparation of microemulsion (ME), namely 1-(2-hydroxyethyl)piperazinium laurate ([HEP][C11CO2]). Important fundamental physicochemical properties have been investigated, revealing higher surface activity for the SAIL than common surfactants. [HEP][C11CO2] is able to solubilize different oil components and water with short-chain alcohol as cosurfactant, forming stable ME in a wide range of ratio of water to oil, and a broad microemulsion region covering over 50 % of the pseudo-ternary phase diagram can be found. The structural transition of water-in-oil to bicontinuous occurs at the water content of 0.60 to 0.65 for the SAIL/1-butanol/n-heptane/water systems at the ratios of SAIL to 1-butanol of 1:1 and 1:2, as confirmed by electrical conductivity measurements. Moreover, the solubilization of oil and water was investigated in the presence of NaCl, KCl or MgCl2, and the optimal salinity was determined. While Mg2+ induces formation of emulsion probably due to the poor solubility of Mg2+/[C11CO2]− complexes, the ME system is much more stable with the presence of monovalent ions like Na+ and K+. For the NaCl-contained system, the salinity window of the bicontinuous phase changes from 0.030 to 0.025 and 0.020 when the temperature rises from 15 °C to 25 °C and 35 °C, which mainly results from the enhanced hydrophobic interactions and the weakened electrostatic interactions. Present studies elucidate that [HEP][C11CO2] is feasible to form various microemulsion systems which may have extensive potential in further applications like size-controlled syntheses and oil recovery.

Metal Ions Removal from Contaminated Water Using Membranes Functionalized with Ionic Liquids

The present work studies the efficiency of new innovative quaternized polysulfone (PSFQ)/ionic liquid (IL) membranes in the treatment process of water containing cadmium ions (Cd(II)). The design and development of the polysulfone membranes with morphology tailored by the use of ILs (Cyphos 101 IL and Aliquat 336) was based on the rheological study of the casting solutions that dictated the optimal compositions of ILs and facilitated the preparation of the membranes for performance tests. Thus, according to the variation of the rheological functions obtained (G′, G″), it was demonstrated that Aliquat 336 has better compatibility with PSFQ, facilitating the workability of the solution and improving the final properties of the membranes relative to Cyphos 101 IL. However, the casting solutions consisting of 5 wt.% Ph-IL and 15 wt.% Am-IL content produce membranes with superior physico-chemical properties. Also, the surface chemistry and morphology analysis of the membranes obtained were investigated in order to understand the relationship between the PSFQ and ILs, as well as their surface properties, as indicators for their future applications. Additionally, the results obtained from the kinetic studies regarding Cd(II) removal from aqueous solutions and the amount of Cd(II) accumulated onto the membranes showed that the ILs enhance the filtration efficiency of the membranes studied and underlined the positive effect of IL in the structure of the quaternized polysulfone membranes. A content of 15 wt.% Aliquat 336 in PSFQ membranes shows the best properties for Cd(II) removal from aqueous solutions; the maximum amount of Cd(II) accumulated on the membrane studied was 3300 mg/m2. This behaviour was maintained for two cycles of washing/filtration, and then the efficiency decreased by 20%. The results obtained showed that the membranes functionalized with ionic liquid could be used efficiently in the treatment of water containing trace concentration of cadmium.

Nanocellulose-Based Polymer Composites Functionalized with New Gemini Ionic Liquids.

The manuscript discusses the application of dimeric imidazolium ionic liquids with an aliphatic linker of different lengths, constituting a new class of compounds called gemini, for the modification of renewable materials. This innovative functionalization with the use of ionic liquids made it possible to obtain polymer composite nanomaterials with renewable fillers, which will reduce the consumption of petroleum-based raw materials and also be directly related to the reduction of energy intensity. Renewable filler in the form of nanocellulose modified with ionic liquids, as well as polymer composites with such filler obtained by extrusion and injection molding techniques, were subjected to detailed characterization using techniques like: X-ray diffraction (XRD), Fourier transform spectroscopy (FTIR), dispersion studies (DLS), morphological analysis (SEM), differential scanning calorimetry (DSC), hot-stage polarized light microscopy and characterization of mechanical properties. The use of innovative dimeric ionic liquids proved to be an effective method to carry out efficient functionalization of cellulose. This provided a stable space structure between polysaccharide particles, limiting aggregate formation. It was shown that chemical modification with ionic liquids has a significant effect on the nucleation activity of cellulose fillers and the formation of the supermolecular structure of the polymer matrix, which consequently allowed to obtain polymer composites with excellent strength characteristics and increased flexibility, which will allow to increase their application potential. Innovative ionic liquids have contributed to obtaining green nanomaterials with excellent functional properties, which have not been described in the literature so far.

Progress on Electrodeposition of Metals and Alloys Using Ionic Liquids as Electrolytes

The electrodeposition process of metals and their alloys is widely used in the automotive, space, electronics, computing, jewelry, and other consumer items industries. Over the years, the search for new coatings with more suitable characteristics for their application led to the use of ionic liquids (ILs) as electrolytic solutions. In addition to having good conductive properties, the growing interest in these solvents has environmental appeal due to their low toxicity. Furthermore, the ability of these electrolytes to dissolve compounds containing less soluble metals makes them potential substitutes for environmentally harmful solvents. In this sense, this review describes the current state and the innovations concerning the electrodeposition of metals and alloys using ILs as electrolytes in the last five years. Metals were classified into five groups (common, light, noble, rare earth, and others), highlighting not only the ability to form a smooth, homogeneous, and anti-corrosive deposit, but also the reactive capacity of metals in hydrogen evolution and catalytic processes.

Technological advancements in the use of ionic liquid- membrane systems for CO2 capture from biogas/flue gas - A review

Carbon capture has become a very important method for curbing the problems associated with the release of carbon dioxide into the atmosphere, which in turn has detrimental effects on the planet and its inhabitants. Ionic liquids and membrane separation have been explored in this review paper as effective means of capturing carbon dioxide. An innovative approach to CO2 capture is the use of Ionic liquids (ILs) since they exhibit certain significant traits such as good stability (thermal, mechanical and chemical), inflammability and high absorptive capacities. Ionic liquids (ILs) are widely regarded as nontoxic substances. Viscosity and thermal degradation of ILs at temperatures slightly above 100 °C are the major disadvantages of ILs. Membrane separation is a technique used for the effective separation of substances by materials bearing holes in a continuous structure. Membrane technology has gained significant improvements, over the years. Several ILs and membrane systems were considered in this work. Their weaknesses, strengths, permeability, selectivity, operating conditions and carbon capture efficiencies, were all highlighted in order to gain a good perspective on ways by which the individual systems can be improved upon. The study considered several polymer-Ionic liquid hybrid materials as viable options for CO2 capture from a post-combustion process. Different ILs were scrutinized for possible integration in membranes by taking full advantage of their individual properties and harnessing their tune-able characteristics in order to improve the overall carbon capture performance of the system. Several options for improving the mechanical, chemical, and thermal stabilities of the hybrid systems were considered including the use of cellulose acetate membrane, nanoparticles (graphene oxide powder) alongside potential ionic liquids. Doping membranes with ILs and nanoparticulates such as graphene oxide serves as a potential method for enhancing the CO2 capture of membranes and this review provides several evidences that serve as proofs for this concept.

Recovery of Cellulose from Polyester/Cotton Fabrics Making Use of Ionic Liquids

Polymer Science: Peer Review Journal Recovery of Cellulose from Polyester/Cotton Fabrics Making Use of Ionic Liquids Villalta Boza E, Riba-Moliner M and Lis Arias MJ* INTEXTER-UPC Colon, 15 08222 Terrassa, Barcelona, Spain *Corresponding author:Lis Arias MJ, INTEXTER-UPC Colon, 15 08222 Terrassa, Barcelona, Spain, ORCID Number: 0000- 0002-2026-085X M Riba Moliner ORCID Number: 0000-0003-0001-2055 Submission: November 04, 2022;Published: November 29, 2022 DOI: 10.31031/PSPRJ.2022.04.000590 ISSN: 2770-6613 Volume4 Issue3

Insights on Some Polysaccharide Gel Type Materials and Their Structural Peculiarities.

Global resources have to be used in responsible ways to ensure the world's future need for advanced materials. Ecologically friendly functional materials based on biopolymers can be successfully obtained from renewable resources, and the most prominent example is cellulose, the well-known most abundant polysaccharide which is usually isolated from highly available biomass (wood and wooden waste, annual plants, cotton, etc.). Many other polysaccharides originating from various natural resources (plants, insects, algae, bacteria) proved to be valuable and versatile starting biopolymers for a wide array of materials with tunable properties, able to respond to different societal demands. Polysaccharides properties vary depending on various factors (origin, harvesting, storage and transportation, strategy of further modification), but they can be processed into materials with high added value, as in the case of gels. Modern approaches have been employed to prepare (e.g., the use of ionic liquids as "green solvents") and characterize (NMR and FTIR spectroscopy, X ray diffraction spectrometry, DSC, electronic and atomic force microscopy, optical rotation, circular dichroism, rheological investigations, computer modelling and optimization) polysaccharide gels. In the present paper, some of the most widely used polysaccharide gels will be briefly reviewed with emphasis on their structural peculiarities under various conditions.

Toward Sustainable and Cost‐Effective CO2 Conversion Processes to Propylene Carbonate Based on Ionic Liquids

AbstractThe use of ionic liquids (ILs) for CO2 capture and utilization into a valuable product is attracting interest even though literature evaluating their sustainability is scarce. A liquid–liquid extraction (LLE)‐based separation is recently proposed as an alternative to the high energy‐consuming distillation‐based reference approach to produce propylene carbonate (PC). In this work, the environmental impacts associated to the distillation‐based reference and two proposed LLE‐based approaches to produce PC are evaluated by means of process modeling and life cycle impact assessment tools. Simulations prove that tuning operating variables in terms of environmental benefits also improves the cost‐effectiveness of the process. In addition, sustainability of the processes is nearly not altered by the IL selection when an effective recovery is designed. The emissions associated to the proposed approaches vary between 0.12 and 0.22 kg CO2 equiv. per kgPC, while the operational costs range from 3 to 8 $ per tPC. The water‐mediated LLE‐based approach imposes the best environmental, capital expenditures, and operating expenses performance.

Multifunctional Characteristics of Carbon Fibers Modified with Imidazolium Ionic Liquids.

A multifunctional designing approach is of great importance for advanced composite applications. This study assessed the use of ionic liquids (ILs) to modify the surface of carbon fiber (CF) and impart multifunctional characteristics to it. For that, ethanolic solutions of different ILs, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium chloride and 1-(2-hydroxyethyl)-3-methylimidazolium chloride, at different concentrations, were used to treat the CF. Fourier-transform infrared spectroscopy confirmed the presence of IL on the CF surface. The contact angle for 1% w/v IL-treated CF and DGEBA epoxy decreased by up to 35%, corresponding to an increase in surface energy of fiber, accompanied by an increase of 91% in interfacial shear strength. These enhancements were achieved with the hydroxy-functionalized IL, showing the tunability of CF properties through the N-imidazolium substituent. An increase in crystallite size along the basal plane was also found due to the ordering of the graphitic structure on the surface. Moreover, there was a decrease in electrical resistivity of 77%. In all, the imidazolium ILs were considered a promising approach to induce multifunctional characteristics, namely enhanced interfacial strength and electrical conductivity, to unsized CF, which can also be beneficial for recycled fibers without deteriorating their inherent surface properties.

Study on functionalized acidic imidazolium‐based ionic liquids as effective adsorbents for HCHO storage

AbstractBACKGROUNDRecent works have shown how to develop methods with specific economic and environmental aspects; this is the main motivation for research on energy efficient processes and environmentally friendly materials for formaldehyde (HCHO) storage. One specific goal is to improve the adsorption capacity for HCHO by constructing closely contacted connections with absorbents.RESULTSIn this study, two ionic liquids (ILs), 1‐methylimidazole hydrogen sulfate [MIM][HSO4] and Imidazole hydrogen sulfate [IM][HSO4] as newly developed absorbents for HCHO storage are applied for the first time. Based on thermogravimetric analysis (TGA) and nuclear magnetic resonance (NMR) results, it is concluded that their exceptional capacity for storage of HCHO is 31.07 and 34.60 (g formaldehyde)⋅(mol ionic liquid)−1, respectively. In addition, to study the renewability of HCHO, the decomposition rates of the reaction products (as a function of decomposition time and decomposition temperature) were measured. The optimal kinetic model was selected to satisfy the formation and decomposition processes of the products. Thereafter, the activation energy (E), pre‐finger factor (A), decomposition rate constant of the decomposition reaction, and the rate constant of the reaction were determined. NMR results confirmed that the higher storage capacity of HCHO in [MIM][HSO4] and [IM][HSO4] is mostly attributed to the stronger covalent bonds between the ionic liquids (ILs) and HCHO.CONCLUSIONThese ILs are, thus, promising candidates as adsorbents for the design of air depollution processes. This study may provide new insights into the use of ILs for storage of HCHO for low‐cost, high‐performance, and environmentally benign adsorbents for indoor air purification. © 2022 Society of Chemical Industry (SCI).

Ionic liquid assisted nanocellulose production from microcrystalline cellulose: Correlation between cellulose solubility and nanocellulose yield via COSMO-RS prediction

The use of ionic liquids (ILs) in nanocellulose (NC) production from cellulosic materials has gained significant interest due to the intrinsic physical solubility of cellulosic materials in many ILs. However, given the numerous possible cation–anion combinations, selecting potential candidates from thousands of ILs for NC production is rather difficult. In addition, NC yield depends on the types of ILs and their capability in dissolution of cellulosic materials. In this study, we investigate NC production from microcrystalline cellulose (MCC) using various ILs as a reaction medium. Firstly, the prediction of MCC solubility in 300 ILs (15 cations and 20 anions) was obtained by deploying the conductor-like screening model for real solvents (COSMO-RS) which has emerged as a reliable and promising tool for solvents screening based on the dominant interactions of H-bonds, misfits, and Van der Waals energies of the fluid mixture. Experimental measurement of NC production from MCC in six ILs, namely [Emim][OAc], [Bmim][OAc], [Bmim][Cl], [Emim][HSO4], [Bmim][HSO4], and [Hmim][HSO4], was conducted. Based on the logarithmic activity coefficient prediction at infinite dilution, there was a negative correlation between cellulose solubility and experimental NC yield obtained. [Hmim][HSO4] IL showed the highest nanocellulose yield (65%) due to a relatively weaker H-bonding ability with cellulose. Moreover, the multiparameter scale of the Kamlet-Taft of six ILs revealed that the increase in alkyl side chain length of the IL cation resulted in a decrease of hydrogen bonding acidity, which contributed to higher NC yield. The quantitative prediction of COSMO-RS, coupled with the experimental study, can therefore be utilized to screen, and classify the potential ILs to prepare nanocellulose.

Electrical conductivity and tribological behavior of an automatic transmission fluid additised with a phosphonium-based ionic liquid

There are electric vehicle configurations with the electric motor (EM) inside the transmission housing, putting in contact the automatic transmission fluid (ATF) with the EM. In this case the ATF must fulfil several requirements, such as electrical and material compatibilities, improved cooling performance, etc. The use of ionic liquids (IL) as lubricant additive can impact on electrical conductivity (κ) and tribological behaviour of the ATF. This work analyses the influence of a phosphonium-based ionic liquid ([P6,6,6,14][BEHP]) used as additive at 1 and 3 wt% concentration on the abovementioned properties of a commercial ATF. The addition of the IL increased the κ of the ATF but it continues being dissipative; however, the dielectric strength decreased drastically and further tests about this property should be performed. The IL promotes the formation of a phosphorous-rich tribofilm, which is related to the improved antiwear performance. This formulation including the IL could be used in electric vehicles.

(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.