Ionic Liquid Mixtures Research Articles

Ionogels based on protic ionic liquid - lithium salt mixtures

The effect of the addition of lithium nitrate on the liquid range and electrical conductivity of mixtures of a protic ionic liquid, ethylammonium nitrate (EAN) with LiNO3 is reported in this work. Moreover, changes in these properties upon confinement in silica-based matrices are also analysed and related to variations on the microstructure of the mixtures. Our results show that gelation of the mixtures induces amorphous behaviour in all the samples, but no significant changes in the thermal stability are detected. However, important differences on the electrical conductivity of the liquid and gel states of the mixtures were observed. While this magnitude decreases with the addition of salt in the liquid samples for all the temperatures it increases at low concentrations of LiNO3 up to a maximum in the gelled samples with the lowest concentration of added salt (0.1 mol of salt by kg of EAN). High resolution magic angle spinning (HRMAS) NMR shows that the addition of lithium nitrate increases the mobility (both rotational and translational motion) of the cation EA+ within the ionogel and the diffusion of the cation provides evidence of the presence of two different populations of the same molecules experiencing two distinct apparent diffusion coefficients (bi-exponential decay of magnetization in diffusion NMR experiments), while it is mono-exponential in the pure ionic liquid. The Li+ cation is shown to display a higher mobility (both rotational and translational motion) in the ionogel than in the neat ionic liquid. The frustration of the formation of solvation complexes due to the confinement is suspected to be behind this behaviour.

A state-of-the-art theoretical method for estimating ultrasonic velocity in ionic liquid mixtures: An extension of McAllister's interaction model

McAllister’s Interaction Model has been extended to predict ultrasonic velocities in eight binary mixtures of ionic liquids and water at temperatures T = 288.15 K, 298.15 K, and 308.15 K.The ionic liquids chosen for the current study are [BMim][TfO], [BMpyr][TfO], [BMpy][TfO], [BMim][dca], [HMim][dca], [BMpyr][dca], [Mpy][MSO4], and [EEpy][ESO4]. The interactions considered in present cases have been investigated for a range of variations from three-body interactions to nine-body interactions. The experimental values of ultrasonic velocities for all the mixturesat temperatures T = 288.15 K, 298.15 K, and 308.15 Kare compared with the computed values. The differences between the experimental and theoretically predicted velocities are determined in terms of absolute percentage deviation. It is worth mentioning that McAllister’s Model of interactions has been extended, for consideration, from three-body interactions to nine-body interactions among constituent molecules of binary mixtures and applied for the prediction of ultrasonic velocities in binary mixtures of water and ionic liquids for the first time. The extended Huckel theory (EHT) is used to calculate the charge distributions in eight ionic liquids and water molecules to understand the active sites available for interactions on each constituting molecule of the binary mixtures under investigation. The results we obtained complemented our decision to extend McAllister’s interactions model (MAIM) to higher orders (four-body to nine-body interactions). The results obtained (using extended MAIM) report an excellent agreement with experimental velocity values for nine-body interactions for all the systems under study. It is also pointed out that McAllister’s assumption that the free energies of activation are the additive quantity for viscosity investigation in organic liquid mixtures is also valid in the case of ultrasonic velocity studies for ionic liquids and water mixtures. Considering McAllister’s conjecture that rather than a planar system of interactions among solvent-solute molecules, a three-dimensional approach to intermolecular interactions can be more appropriate, authors have confirmed the validity of McAlliter’s conjecture by successfully investigating three-dimensional multi-body (in the present case: 9-body) interactions in the binary mixtures of ionic liquids and water.

Study on association and thermal stability of binary imidazolium ionic liquid mixtures

Ionic liquid (IL) mixtures with specific properties can be designed by the combination of different ionic liquids (ILs), but there are few studies on the physicochemical properties of IL mixtures with different ratios. Thus, this work explores the association and thermal stability of binary imidazolium IL mixtures. In particular, the physicochemical properties of binary IL mixtures at different ratios were investigated. Four different ILs, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), 1-butyl-3-methylimidazolium nitrate ([BMIM][NO3]), 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM][TFO]), and 1-butyl-3-methyl-imidazolium trifluoroacetate ([BMIM][CF3COO]), were selected as the parent salts to form the different binary imidazolium IL mixtures. These IL mixtures were tested at different temperatures (25, 30, 35, 40, 45, and 50 °C) and ratios (1:9, 3:7, 5:5, 7:3, and 9:1) by viscometer, conductivity meter, and then by isothermal thermogravimetric analysis in the temperature rise range of 30–500 °C. It was found that the increase in temperature decreased the association of IL mixtures, thus destroying the association behavior between the parent salts. Accordingly, different ratios of the parent salts had no significant effect on the thermal stability of some IL mixtures. Moreover, the results showed that smaller anions were more likely to combine with cations to form ion clusters or ion pairs, enhancing the association of binary IL mixtures. Thus, it increased the thermal stability of IL mixtures.

Exploring the behavior of Candida antarctica lipase B in aqueous mixtures of an imidazolium ionic liquid and its surfactant analogue.

The performance of Candida antarctica lipase B (CALB) has been evaluated in 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4)/water mixtures in a wide range of molar fractions () with and without 1-dodecyl-3-methylimidazolium tetrafluoroborate (C12-MIMBF4), a surfactant derived from BMIMBF4. The main aim of this work is to evaluate the influence of over micellar aggregates to assess the activity of enzymatic reactions. The investigated reaction corresponds to the hydrolysis of the substrate p-nitrophenyl laureate in each . The kinetic study for at around 0.2 proved to be a border point in enzymatic activity. At = 0.1, the lipase activity increases in the presence of C12-MIMBF4. However, at higher concentrations, BMIMBF4 has a negligible effect over the lipase activity. These results suggest specific interactions between water and BMIMBF4 molecules in relation to CALB. This research highlights the superactivity phenomenon driven by the reaction media and the micelle interface. In this interfacial interaction, BMIMBF4 acts directly on the changes induced on the enzyme upon its interaction with the micellar interface. This study opens a green perspective toward the biocatalysis field.

Chain-length dependent organisation in mixtures of hydrogenous and fluorous ionic liquids.

As part of an ongoing study of the structure and properties of mixtures of ionic liquids in which one component has a hydrocarbon chain and the other a semiperfluorocarbon chain, we now report a study of the mixtures [C8MIM]1-x[C10MIM-F17]x[Tf2N], [C10MIM]1-x[C8MIM-F13]x[Tf2N] and [C10MIM]1-x[C10MIM-F17]x[Tf2N], where [C8MIM][Tf2N] is 1-methyl-3-octylimidazolium bis(trifluoromethylsulfonyl)imide, [C10MIM][Tf2N] is 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C8MIM-F13][Tf2N] is 1-(1H,1H,2H,2H-perfluorooctyl)-3-methylimidizolium bis(trifluoromethylsulfonyl)imide and [C10MIM-F17][Tf2N] is 1-(1H,1H,2H,2H-perfluorodecyl)-3-methylimidizolium bis(trifluoromethylsulfonyl)imide. The mixtures were investigated using small-angle X-ray (SAXS) and neutron (SANS) scattering complemented by molecular dynamics simulations (with viscosity and surface tension measurements also possible for the mixtures [C10MIM]1-x[C8MIM-F13]x[Tf2N]). Unlike previous studies of [C8MIM]1-x[C8MIM-F13]x[Tf2N], where no strong evidence of alkyl/fluoroalkyl chain segregation or triphilic behaviour was seen (Elstone et al., J. Phys. Chem. B, 2023, 127, 7394-7407), these new mixtures show the formation of small aggregates of varying sizes of each component, even though all were co-miscible across the full range of compositions. Thus, while a clear polar non-polar peak (PNPP) was observed at large or small values of x, at intermediate compositions the small-angle neutron scattering at low q was dominated by scattering from these small aggregates, while at other compositions, there was little or no evidence of the PNPP. The origins of this behaviour are discussed in terms of inter-chain interactions.

Wave mechanics in an ionic liquid mixture.

Experimental measurements of interactions in ionic liquids and concentrated electrolytes over the past decade or so have revealed simultaneous monotonic and oscillatory decay modes. These observations have been hard to interpret using classical theories, which typically allow for just one electrostatic decay mode in electrolytes. Meanwhile, substantial progress in the theoretical description of dielectric response and ion correlations in electrolytes has illuminated the deep connection between density and charge correlations and the multiplicity of decay modes characterising a liquid electrolyte. The challenge in front of us is to build connections between the theoretical expressions for a pair of correlation functions and the directly measured free energy of interaction between macroscopic surfaces in experiments. Towards this aim, we here present measurements and analysis of the interactions between macroscopic bodies across a fluid mixture of two ionic liquids of widely diverging ionic size. The measured oscillatory interaction forces in the liquid mixtures are significantly more complex than for either of the pure ionic liquids, but can be fitted to a superposition of two oscillatory and one monotonic mode with parameters matching those of the pure liquids. We discuss this empirical finding, which hints at a kind of wave mechanics for interactions in liquid matter.

Self-propelled motion controlled by ionic liquids.

We studied the self-propulsion of a camphor disk floating on a water surface using two types of ionic liquids (hexylammonium-trifluoroacetate (HHexam-TFA) and hexylethylenediaminium-trifluoroacetate (HHexen-TFA)). Bifurcation between continuous, oscillatory, and no motion was observed depending on the concentration of the ionic liquid. The bifurcation concentration between oscillatory and no motion for HHexam-TFA was lower than that for HHexen-TFA. The different bifurcation concentrations are discussed in relation to the surface tension and Fourier transform infrared spectra of the mixtures of camphor and ionic liquids. These results suggest that the interaction between the ionic liquid molecules at the air/water interface is weakened by the addition of camphor molecules and the features of self-propulsion vary due to the change in the driving force.

Dispersions of magnetic nanoparticles in water/ionic liquid mixtures.

Nanoparticles (NPs) of iron oxide are dispersed in mixtures of water and ionic liquid, here ethylammonium nitrate (EAN), and the NP/NP and NP/solvent interactions are studied. They are analysed via small-angle X-ray scattering and dynamic light scattering coupled to forced Rayleigh scattering, from 22 °C to 80 °C. The NPs are well-dispersed as individual objects in the whole range of compositions and temperatures thanks to sufficient repulsion due to the organization of the solvents at the interface. The surface changes from hydrophilic to hydrophobic around a proportion of 50 vol% water : 50 vol% EAN, following the evolution of the bulk mixtures, which remain heterogeneous in the whole range of compositions.

Origin of ργ/T scaling of primary and secondary conductivity relaxation times in mixture of water with protic ionic liquid.

Murali et al. [J. Phys. Chem. Lett., 2024, 15, 3376-3382] made ambient and high pressure dielectric measurements of a supercooled aqueous mixture of an acidic ionic liquid to find the presence of the primary (σ) conductivity relaxation together with the secondary (ν) conductivity relaxation originating from the water clusters confined by the cations and anions with relaxation times τσ and τν respectively. From the isothermal and isobaric conductivity relaxation data found on varying thermodynamic conditions (i.e. T and P) at constant τσ are the invariance of (i) the frequency dispersion or the Kohlrausch function exponent (1 - n) of the primary conductivity relaxation, and (ii) the ratio of the primary and secondary conductivity times, τσ/τν. This co-invariance of τσ, τν, and (1 - n) at constant τσ was observed before in non-aqueous ionic liquids, but it is found for the first time in aqueous ionic liquids. The new data together with PVT measurements enable Murali et al. to show additionally that both τσ and τν are functions of ργ/T with a single exponent γ = 0.58. The Coupling model is the only theory predicting the co-invariance of τσ, τν, and (1 - n) as well as the ργ/T scaling of both τσ and τν. It is applied herein to address and explain the data of the ionic liquid-water mixture.

An eminent approach towards next generation solvents for sustainable packaging and stability of enzymes: a comprehensive study of ionic liquid and deep eutectic solvent mixtures.

Hybrid ionic fluids (HIFs) are newly emerging and fascinating sustainable solvent media, which are attracting a great deal of scientific interest in protecting the native structure of proteins. For a few decades, there has been a demand to consider ionic liquids (ILs) and deep eutectic solvents (DESs) as biocompatible solvent media for enzymes; however, in some cases, these solvent media also show limitations. Therefore, this work focuses on synthesising novel HIFs to intensify the properties of existing ILs and DESs by mixing them. Herein, HIFs have been synthesised by the amalgamation of a deep eutectic solvent (DES) and an ionic liquid (IL) with a common cation or anion. Later on, the stability and activity of hen's egg white lysozyme (Lyz) in the presence of biocompatible solvent media and HIFs were studied by various techniques such as UV-vis, steady-state fluorescence, circular dichroism (CD), Fourier transform infrared spectroscopy (FT-IR) and dynamic light scattering (DLS) measurements. This work emphasises the effect of a DES (synthesised using 1 : 2 choline chloride and malonic acid) [Maline], ILs (1-butyl-3-methylimidazolium chloride [BMIM]Cl or choline acetate [Chn][Ac]) and their corresponding HIFs on the structure and functionality of Lyz. Moreover, we also studied the secondary structure, thermal stability, enzymatic activity and thermodynamic profile of Lyz at pH = 7 in the presence of varying concentrations (0.1 to 0.5 M) of [BMIM]Cl and [Chn][Ac] ILs, Maline as a DES, and Maline [BMIM]Cl (HIF1) and Maline [Chn][Ac] (HIF2). Spectroscopic results elucidate that ILs affect the activity and structural stability of Lyz. In contrast, the stability and activity are inhibited by DES and are enhanced by HIFs at all the studied concentrations. Overall, the experimental results studied explicitly elucidate that the structure and stability of Lyz are maintained in the presence of HIF1 while these properties are intensified in HIF2. This study shows various applications in biocompatible green solvents, particularly in the stability and functionality of proteins, due to their unique combination where the properties counteract the negative effect of either DESs or ILs in HIFs.

Enhancing boundary friction and wear reduction through adsorption control in protic ionic liquid and carbon mixtures

Enhancing boundary friction and wear reduction through adsorption control in protic ionic liquid and carbon mixtures

Experimental and in silico insights: interaction of dimethyl sulphoxide with 1-hexyl-2-methyl imidazolium bromide/1-octyl-2-methyl imidazolium bromide at different temperatures.

Ionic liquids have gained attention as 'designer solvents' since they offer a broad spectrum of properties that can be tuned by altering the constituent ions. In this work, 1-alkyl-2-methyl imidazolium-based ionic liquids with two different alkyl chains (alkyl = hexyl and octyl) have been synthesized and characterized. Since the binary mixture of ionic liquids with molecular solvents can give rise to striking physicochemical properties, the interaction of the synthesized room temperature ionic liquids, 1-hexyl-2-methyl imidazolium bromide [HMIM][Br]/1-octyl-2-methyl imidazolium bromide [OMIM][Br] with DMSO has been examined through density and specific conductance at T = (303.15, 308.15, 313.15 and 318.15) K under atmospheric pressure. The obtained molar volume and excess molar volume are fitted to the Redlich-Kister polynomial equation, and the standard deviation is noted. The positive excess molar volume at elevated temperatures indicates volume expansion due to the mutual loss of dipolar association and differences in the sizes and shapes of the constituent molecules. To have a better understanding of the reactivity and efficacy of 1-hexyl-2-methyl imidazolium bromide and 1-octyl-2-methyl imidazolium bromide with DMSO, the Becke, 3-parameter, Lee-Yang-Parr (B3LYP) correlation function of density functional theory (DFT) has been used. The ORCA Program version 4.0 calculates the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy. The effective reactivities of both the compounds that showed an energy band gap (ΔE), i.e., the difference between ELUMO and EHOMO, are 7.147 and 8.037 kcal mol-1.

Ionic Liquids, Synthesized and Utilized by Greener Methods, for the Application in High-Voltage Lithium-Ion Batteries

Due to their high energy density and reliability, lithium-ion batteries (LIBs) are a crucial energy storage system for portable electronic devices, which has dominated the market for more than 30 years. To increase their energy density even more, it is imperative to replace the commonly employed cathode materials (such LiCoO2) with cathode materials that can operate at higher potentials, like LiNi0.5Mn1.5O4 (LNMO) working at 4.7V vs Li+/Li. However, standard electrolytes, typically containing carbonate-based solvents (e.g., LP30), are unstable at such high potentials and suffer from oxidation decomposition. To mitigate this problem, ionic liquids (ILs) have recently been proposed as an additive to them. Despite this, their application in industrial-scale is hindered by the high-cost and environmentally unfriendliness of their synthesis [1]. In this study, ILs containing oxalatoborate anions—known to form the so-called cathode-electrolyte interphase (CEI), a protective layer on the cathode surface [2]—have been obtained by using mostly water as solvent, to minimize the impact of the synthesis on the environment. Four different ILs have been synthesized: N-ethoxyethyl-N-methylpiperidinium bis(oxalato)borate (PIP1,2O2BOB), N-ethoxyethyl-N-methylpiperidinium difluoro(oxalate)borate (PIP1,2O2DFOB), N-propyl-N-methylpiperidinium bis(oxalato)borate (PIP1,3BOB) and N-propyl-N-methylpiperidinium difluoro(oxalate)borate (PIP1,3DFOB). All of them have been characterized by IR spectroscopy and thermal analysis (DSC and TGA). The thermal analyses highlighted that all the ILs are thermally stable up to 280°C. Furthermore, PIP1,2O2DFOB and PIP1,2O2BOB did not show any crystallization behavior even at sub-zero temperatures, but only a glass-transition (at -70 °C and -30 °C, respectively). The improved liquid property is related to the presence of an ether oxygen in the cation structure.The four ILs have been then used as the additive for LP30 at a concentration of 0.3M and the resulting mixtures have been tested in Li|LP30+IL|LNMO coin-cells at 1C (147 mA g-1) for over 150 charge/discharge cycles. The results obtained showed that the addition of the ILs to the electrolyte has ensured more stable charge/discharge cycles, with higher coulombic efficiency and improved discharge capacity retention especially in the case of BOB-based ILs, while Li|LP30|LNMO cells prepared as a reference failed after about 100 cycles. On the promise that the ILs play an important role at the surface of cathode, another approach has been tested: 3 wt% of IL has been added directly to the slurry during the preparation of LNMO electrodes. These IL-added electrodes have been tested in Li|LP30|LNMO+IL coin-cells. Remarkable improvements in the stabilities of the cells have been observed also in this case. In IL-added electrodes, the total amount of IL in the system is almost 40 times smaller than that used in LP30+IL mixtures as the electrolytes. These results show that presence of ILs closer to the electrode is crucial to obtain an improvement of the stabilities of high-voltage cathodes. The combination of greener synthesis and utilization is expected to enhance the sustainability of LIBs.[1] E. Simonetti, M. De Francesco, M. Bellusci, G. Kim, F. Wu, S. Passerini, G. B. Appetecchi, ChemSusChem, 2019, 12, 4946– 4952[2] A. Tsurumaki, M. Branchi, A. Rigano, R. Poiana, S. Panero, M.A. Navarra, Electrochimica Acta, 2019, 315, 17-23 Figure 1

Nanoscale Investigations of the Electric Double Layer in Protic Ionic Liquids

A hydrogen-based energy storage system will be the backbone of a future energy grid using renewable energies. Polymer electrolyte membrane fuel cells (PEMFCs) are a key element in this energy system as they convert chemical energy stored as hydrogen into electrical energy on demand. PEMFC systems, especially for automotive application, could be significantly improved by increasing the operation temperature above 100 °C. Protic ionic liquids are promising candidates as non-aqueous protic electrolytes for next-generation high-temperature polymer electrolyte membrane fuel cells. These fuel cells have a target operation temperature of 160 °C and allowing for a more efficient water and heat management compared to conventional Nafion®-based PEMFCs, which operate at temperatures below 80 °C [1].In order to ensure a reliable and efficient operation an electrolyte with a high electrochemical performance and stability has to be selected. For this purpose, protic ionic liquids have been proposed and first fuel cell tests have shown promising results [2]. Hence, we aim on understanding the properties of this class of novel electrolytes on an atomistic level, which would allow designing suitable material combinations and predicting their properties for an efficient fuel cell operation. As ionic liquids are molten salts, which are liquid below 100 °C, their electrochemical properties differ significantly from those of aqueous solutions. Instead of a classical electric double layer, which can be described by the models provided by Helmholtz, Gouy-Chapman and Stern, the interface structure formed between the electrolyte and a charged electrode is governed by the interplay between coulomb interaction and steric effects between the (large) molecular ions [3]. In order to understand the formation of this double layer on a metallic electrode, we employ atomic force microscopy and infrared spectroscopy in combination with molecular dynamics simulations. Our results show that in the interface region between the prototype protic ionic liquid diethylmethylammonium triflate ([Dema][TfO]) and a Pt electrode, a dense layered structure consisting of alternating anion and cation layers is present, that extends several nanometres into the bulk of the electrolyte [4]. The composition and structure changes with applied potential due to a preferential attraction of anions or cations depending on the electrode charge. When water is added to the ionic liquid, the layered structure becomes distorted and water molecules appear near the electrode. Since the presence of water will also influence the relevant electrochemical processes such as the oxygen reduction reaction (ORR), the analysis of the double layer structure on an atomistic scale is necessary in order to understand the subtle interactions between the molecules in the electrolyte and to propose design routes for novel more efficient ionic liquid-based electrolytes. Wippermann, K.; Suo, Y.; Korte, C. Oxygen Reduction Reaction Kinetics on Pt in Mixtures of Proton-Conducting Ionic Liquids and Water: The Influence of Cation Acidity. J. Phys. Chem. C 2021, 125, 4423–4435, doi:10.1021/acs.jpcc.0c11374.Skorikova, G.; Rauber, D.; Aili, D.; Martin, S.; Li, Q.; Henkensmeier, D.; Hempelmann, R. Protic Ionic Liquids Immobilized in Phosphoric Acid-Doped Polybenzimidazole Matrix Enable Polymer Electrolyte Fuel Cell Operation at 200 °C. Journal of Membrane Science 2020, 608, 118188, doi:10.1016/j.memsci.2020.118188.Rodenbücher, C.; Wippermann, K.; Korte, C. Atomic Force Spectroscopy on Ionic Liquids. Applied Sciences 2019, 9, 2207, doi:10.3390/app9112207.Rodenbücher, C.; Chen, Y.; Wippermann, K.; Kowalski, P.M.; Giesen, M.; Mayer, D.; Hausen, F.; Korte, C. The Structure of the Electric Double Layer of the Protic Ionic Liquid [Dema][TfO] Analyzed by Atomic Force Spectroscopy. International Journal of Molecular Sciences 2021, 22, 12653, doi:10.3390/ijms222312653. Figure 1

Extraction of Pyrrole from Its Mixture with n-Hexadecane Using Ionic Liquids and Their Binary Mixtures.

The conventional hydrodenitrogenation method is expensive and involves the use of catalysts and harsh procedures. In the last few years, ionic liquids (ILs) have gained attention as a promising alternative solvent for fuel oil extractive denitrogenation. In this work, the Conductor-like Screening Model for Real Solvents (COSMO-RS) was used to screen 173 potential ILs as solvents for fuel oil. Two ILs (1-ethyl-3-methylimidazolium dicyanamide ([EMIM][N(CN)2]) and 1-ethyl-3-methylimidazolium methanesulfonate ([EMIM][MeSO3])) were selected for experimental investigation. The experimental liquid-liquid extraction of pyrrole (taken as the model nitrogen compound) from n-hexadecane (the model fuel) was conducted at 298 K and 1 atm with feed concentrations of pyrrole ranging from 10 to 50 wt%, using either the two pure ILs or their mixtures with dimethylformamide or ethylene glycol. Moreover, the NRTL model was effectively used to correlate the experimental tie lines. This work shows that the use of a binary mixture of ILs with a conventional solvent results in good selectivity, but has a low capacity for extracting pyrrole compounds. On the other hand, using an IL-IL mixture exhibits good results for both capacity and selectivity. All the ternary systems tested showed positive slopes, indicating that the nitrogen compounds had a higher affinity for the IL and binary mixture extract phase. In fact, the extraction efficiency for all the systems shows promising results. This characteristic is advantageous, as it requires less solvent to remove nitrogen compounds.

Synthesis of new imidazole-based ionic liquids with antifungal activity against Candida albicans.

Candida albicans cause a problematic condition in immunocompromised patients that could not be treated quickly due to the resistant behavior of microorganisms. This study aimed to investigate the effect of a novel ionic liquid (IL) as a new drug on C. albicans strains. Seven newly binary ionic liquids mixtures were synthesized, and among them, ([prollinium chloride] [1-methylimidazolium 3-sulfonate] ([pro-HCl][MImS]) was selected and characterized by 1HNMR, 13C NMR, and FT-IR methods. Samples from patients (n=50) with candidiasis were collected and identified through culture media. ERG11 gene overexpression was related to resistance against azole-bearing drugs. The antibiogram, well diffusion assay, MICs, and MFCs tests were operated. PCR and Real-time evaluated the expression of the ERG11 gene, and the rate of cell death was detected using Flow Cytometry. Our data manifested that this novel IL (Ionic Liquid) can inhibit C. albican's growth, reduce the expression of ERG11 and increase dead cells. The newly synthesized IL had an inhibiting effect on the growth of the C. albicans strains and may be used as an alternative candidate for novel drug design.

Prediction of Refractive Indices of Binary Mixtures of Ionic Liquids and Water

In the present work, we have successfully predicted the refractive indices of binary mixtures containing ionic liquids (ILs) and water as a component following the approach of Gladstone–Dale and Newton. These approaches were proposed as adequate to predict the refractive indices of mixtures containing imidazolium-based ILs with water or ethanol. It requires just the knowledge of the density and refractive index of pure components to obtain the value of refractive index of binary mixtures at any composition. We have selected 30 binary systems that contain ILs from imidazolium, ammonium, pyrrolidinium, and pyridinium families for validation. The tested data comprise of more than 400 mixture points. The results are presented in terms of average percentage deviations (APDs) from the experimental values. The Gladstone–Dale method gives better results compared to the Newton approach. The reasons why these approaches give large APDs for some mixtures are discussed in the manuscript.

Structures and dynamics of protic [EtNH3][NO3] and aprotic [Emim][NO3] ionic liquid mixtures around the single-walled carbon nanotubes: The critical role of imidazolium-based cations

Molecular dynamics (MD) simulations and a series of ab initio calculations have been applied to systematically investigate the structural and dynamic properties for ionic liquid (IL) mixture of equimolar protic [EtNH3][NO3] and aprotic [Emim][NO3] around the single-walled carbon nanotubes (SWCNTs) of (4,4), (8,8) and (12,12). Our simulation results demonstrated that ions of IL mixtures display a well-defined shell structures at the interface irrespective of the diameters of SWCNTs. The aprotic [Emim]+ cations adsorb preferentially over protic [EtNH3]+ at the interface of SWCNTs irrespective of its diameters. Further analysis reveals that these two cations and the [NO3]– anions display ordered arrangement in the first solvation shell. Accordantly, the rotational dynamics of interfacial [Emim]+ and [EtNH3]+ cations decay much slower than those of the bulk curves, suggesting the rotational motions of these two cations at the interface of the SWCNTs are significantly restricted. Interfacial [Emim]+ cations decay much slower rotational motions as the SWCNTs diameter increases. However, for interfacial [EtNH3]+ cations, because they are far from the interface, they display similar rotations regardless of the SWCNTs diameters. More importantly, the HB lifetime of interfacial [Emim]+–[NO3]– and [EtNH3]+–[NO3]– are much longer than the corresponding bulk values due to the restrictions on the rotational motions of cations, suggesting the strength of these two HBs are enhanced at the interface. The binding energies for the above HBs were determined by the ab initio calculations, which are in accordance with the MD simulation results. Our results provide a molecular-level understanding the structural and dynamic properties of [EtNH3][NO3] and [Emim][NO3] IL mixtures around the SWCNTs, which highlighted the critical role of the imidazolium-based cations.

Modelling mixtures of ammonium and pyridinium-based ionic liquids and carbon dioxide with the Cubic Plus Association Equation of state

Modelling mixtures of ammonium and pyridinium-based ionic liquids and carbon dioxide with the Cubic Plus Association Equation of state

Molecular dynamics simulation of the effect of alkyl side chain length on the mixture of imidazolium-based ionic liquids and water

Molecular dynamics simulation of the effect of alkyl side chain length on the mixture of imidazolium-based ionic liquids and water