Common Ionic Liquids Research Articles

Glucose‐based Ionic Liquid Organocatalysts for Asymmetric aza‐Diels‐Alder Reactions

AbstractCarbohydrate‐based ionic liquids and salts (CHILS) have recently emerged as an uprising sub‐class of ionic liquids. Their starting materials are available in abundant natural resources from plants and fauna. Carbohydrates are not only sustainable; they also exhibit natural chirality. To use this, novel glucosyl imidazolium NTf2 ionic liquids were synthesized and applied as organocatalysts in aza‐Diels‐Alder reactions in this work, where we used aldimines and Danishefsky's diene as substrates. We investigated the structure‐activity relationships of these glucosyl imidazolium NTf2 organocatalysts through several functionalizations on the carbohydrate and the imidazole and compared them with common metal catalysts and ionic liquids. Our organocatalysts improved the yield of the model aza‐Diels‐Alder reaction highly and also had a positive effect on the overall diastereomeric excess.

Investigating the ions emitted by multiply charged ionic liquids from a porous electrospray ion source

A porous electrospray ion source was tested with three ionic liquids in order to investigate the effects of ionic liquid properties on the sizes of ion clusters emitted by purely ionic electrospray sources. Two of the ionic liquids, bis(1-ethyl-3-methylimidazolium) tetrathiocyanatocobaltate and 1,6-bis(3-methylimidazolium-1-yl)hexane bis(trifluoromethylsulfonyl)amide, were selected due to them having a dication or dianion, which were termed multiply charged ionic liquids due to them containing anions or cations with more than one charge within them. These were selected in order to investigate ionic clustering within electrospray ion emission and were compared against one of the most common ionic liquids, EMI-BF4. The current–voltage data showed that EMI-BF4 emitted similar levels of current to bis(1-ethyl-3-methylimidazolium) tetrathiocyanatocobaltate, even though the latter liquid had significantly lower conductivity and higher viscosity, suggesting an improvement in current speculated to be due to the extra charges contained by the ions. Time-of-flight and retarding potential analysis data are provided, showing all three liquids emitting ions comprising of monomers, dimers, trimers, and quadramers, with some of the 1,6-bis(3-methylimidazolium-1-yl)hexane bis(trifluoromethylsulfonyl)amide data showing heavier species emission. The data also suggested that the multiply charged ionic liquids produced ions that have two anions or cations attached, termed “double ions,” with these ions not been previously reported using porous electrospray sources. Furthermore, it was found that the dimers emitted by both of the multiply charged ionic liquids seemed to be more stable than EMI-BF4 dimers, providing insight into ion cluster formation.

Absorption-Desorption Characteristics of the Synthesized Deep Eutectic Solvents for Carbon Dioxide Capture

The development of an environmentally friendly CO2 absorbent with significant energy utilization which can be an alternative to CO2 capture by an ethanolamine solution is presently an obligatory issue. In this work, binary and ternary deep eutectic solvents (DESs) were prepared according to their CO2 absorption/desorption performances. A series of DESs comprise different hydrogen bonding donor (HBD)- acceptor (HBA) pairs as CO2 capturing solvents; HBAs include choline chloride (ChCl) and tetrabutylammonium bromide (TBAB), and selected amines are represented as HBDs and include monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA). Binary DESs synthesized of ChCl/MEA, ChCl/DEA, ChCl/TEA, TBAB/MEA, TBAB/DEA, and TBAB/TEA in a CO2 absorption cell at a mole ratio of 1:4. While selected amidines were represented as super-based (SB) and included 1,5-Diazabicyclo [4.3.0] non-5-ene (DBN) and 1,8-Diazabicyclo [5.4.0] undec-7-ene (DBU). The ternary DESs were prepared by adding DBN or DBU to the binary DESs system in a (1:4:3) molar ratio. CO2 absorption experiments were attained at atmospheric pressure and a temperature of 30 °C using 15 vol.% CO2 with 85 vol.% N2. On the other hand, the regeneration process for DESs was conducted at 90 oC. Binary DES synthesized from ChCl/MEA gives a higher absorption rate of CO2 of 0.0177 mole/kg. min, CO2 absorption loading of 2.9092 mole CO2/kg solvent, cyclic loading of 2.0001 mole CO2/kg solvent, and a regeneration efficiency of 68.75%. The synthesis DESs showed a better performance compare with a common Ionic liquids.

SYNTHESIS AND CHARACTERIZATION OF 2-(METHYLAMINO)ETHANOL-BASED DEEP EUTECTIC SOLVENTS FOR CO2 CAPTURE

In recent years, deep eutectic solvents (DESs) have attracted the interest of many researchers for application in a wide range of industrial and scientific fields, including carbon dioxide (CO2) capture. DESs exhibit favourable solvent properties for CO2 removal applications; hence, they have become promising alternatives to common amine solutions and ionic liquids (ILs). In this context, a novel DES was synthesised by mixing 2 (methylamino)ethanol (2-MAE) as a hydrogen bond donor with choline hydroxide (ChOH) as a hydrogen bond acceptor with a molar ratio of ChOH:2-MAE of 1:1. The solubility of CO2 in the prepared systems was determined and characterised before and after CO2 absorption by measuring their physicochemical properties (density and viscosity) and analysing their FTIR spectra. The results showed that the DES and 2M DES aqueous solutions exhibited CO2 absorption capacities comparable to those of other reported DESs. These physicochemical properties were comparable to those reported in the literature. Besides, the FTIR analysis of the studies systems after absorption indicates the formation of carbamate.

Standard partial molar volumes of single aqueous ions composing ionic liquids. Measurement and evaluation of temperature dependent values. Parsing and LSER correlation with molecular descriptors based on DFT/COSMO approach

The densities of highly dilute aqueous solutions (m < 0.2 mol·kg−1) of 50 common ionic liquids (ILs) or related salts were accurately measured at seven equidistant temperatures in the range of (288.15 to 318.15) K and ambient pressure. The examined set of ILs/salts composed of 31 ions was judiciously selected to cover wide ranges of ion sizes and chemical structures and allow reliable evaluation of ionic contributions. The data were duly analyzed to infer related thermodynamic properties and information on the behavior of these systems on a molecular level. Appropriate means of mathematical statistics were used to estimate data uncertainties, assign weights to data correlations, and judge the significance of the results obtained. The standard partial molar volumes V¯∞ of the ILs/salts at infinite dilution were evaluated through fitting the concentration dependence of respective apparent molar volumes to Redlich-Meyer equation and their temperature dependence was correlated to quadratic polynomial. The data presented were compared whenever possible with those available in the literature; good agreement was often found, although some data from the literature were also considerably dispersed or in error. Standard partial molar volumes of ILs/salts obeying ionic additivity were split by least-squares optimization into temperature-dependent single-ion values based on the Conway-Millero extrathermodynamic assumption. The ionic additivity of BV parameter was also identified. Its magnitude for anions is typically greater than that for cations, supporting the fact that an anion dominates the volumetric behavior of aqueous ILs. As the BV,anion and the second temperature derivative ∂2V¯anion∞/∂T2 were found to correlate, the two solute’s water structure making/breaking ability indicators appear to speak consistently. Enhanced values of standard partial molar expansion were observed for both strongly kosmotropic and chaotropic anions and a plausible explanation of this phenomenon was suggested. To correlate and analyze the effect of ionic structure on V¯ion,298∞, Linear Solvation Energy Relationship (LSER) methodology with the recently proposed four quantum chemistry computed descriptors based on DFT/COSMO approach was employed providing excellent fit (SD = 2.48 cm3·mol−1, R2 = 0.9996).

Reliable unencapsulated Ag/Ag2S micro-reference electrodes for battery research and other applications in organic media

Reliable electrochemical measurements depend on the availability of robust reference electrodes (RE) with well-defined potentials. While many reliable REs are known, they are not applicable in certain demanding media such as ionic liquids, nor in small confined spaces. Here, we describe the fabrication of a simple yet robust Ag/Ag2S micro-reference electrode (μ-RE) where a micron-thick Ag2S layer is formed by isothermal reaction with sulfur vapor. Scanning electron microscopy, X-ray photoemission spectroscopy, and spectroscopic ellipsometry characterization reveals that the optimal morphology corresponds to a slightly porous Ag2S film. We demonstrate that the Ag/Ag2S μ-RE can be operated in and cycled through a wide variety of polar organic solvents, including common protic solvents (EtOH), aprotic solvents (ACN, DMSO, NMP, DMF) and ionic liquids (EMIM-TFSI, BMP-TFSI), with short equilibration time (tens of seconds) and little drift (<20 mV), without requiring encapsulation, protective liquid junctions, nor special conditioning. A redox potential of 0.54 ± 0.02 V was obtained for ferrocene in acetonitrile, which places this RE at 0.08 V vs Ag/AgCl. We have also successfully embedded the electrode inside the CR2032 coin cell to perform cyclic voltammetry of battery materials. These results underpin the suitability of this simple micro-reference electrode for a wide variety of electrochemical measurements in demanding and/or miniaturized environments.

Liquid Structure of Ionic Liquids with [NTf2]- Anions, Derived from Neutron Scattering.

The liquid structure of three common ionic liquids (ILs) was investigated by neutron scattering for the first time. The ILs were based on the bis(trifluoromethanesulfonyl)imide anion, abbreviated in the literature as [NTf2]- or [TFSI]-, and on the following cations: 1-ethyl-3-methylimidazolium, [C2mim]+; 1-decyl-3-methylimidazolium, [C10mim]+; and trihexyl(tetradecyl)phosphonium, [P666,14]+. Comparative analysis of the three ILs confirmed increased size of nonpolar nanodomains with increasing bulk of alkyl chains. It also sheds light on the cation-anion interactions, providing experimental insight into strength, directionality, and angle of hydrogen bonds between protons on the imidazolium ring, as well as H-C-P protons in [P666,14]+, to oxygen and nitrogen atoms in the [NTf2]-. The new Dissolve data analysis package enabled, for the first time, the analysis of neutron scattering data of ILs with long alkyl chains, in particular, of [P666,14][NTf2]. Results generated with Dissolve were validated by comparing outputs from three different models, starting from three different sets of cation charges, for each of the three ILs, which gave convergent outcomes. Finally, a modified method for the synthesis of perdeuterated [P666,14][NTf2] has been reported, with the aim of reporting a complete set of synthetic and data processing approaches, laying robust foundations that enable the study of the phosphonium ILs family by neutron scattering.

SBP]BF4 Additive Stabilizing Zinc Anode by Simultaneously Regulating the Solvation Shell and Electrode Interface

The zinc anode mainly faces technical problems such as short circuits caused by the growth of dendrite, low coulomb efficiency, and a short cycle life caused by side reactions, which impedes the rapid development of aqueous zinc-ion batteries (AZIBs). Herein, a common ionic liquid, 1,1-Spirobipyrrolidinium tetrafluoroborate ([SBP]BF4), is selected as a new additive for pure ZnSO4 electrolyte. It is found that this additive could regulate the solvation sheath of hydrated Zn2+ ions, promote the ionic mobility of Zn2+, homogenize the flux of Zn2+, avoid side reactions between the electrolyte and electrode, and inhibit the production of zinc dendrites by facilitating the establishment of an inorganic solid electrolyte interphase layer. With the 1% [SBP]BF4-modified electrolyte, the Zn||Zn symmetric cell delivers an extended plating/stripping cycling life of 2000 h at 1 mA cm−2, which is much higher than that of the cell without additives (330 h). As a proof of concept, the Zn‖V2O5 battery using the [SBP]BF4 additive shows excellent cycling stability, maintaining its specific capacity at 97 mAh g−1 after 2000 cycles at 5 A g−1, which is much greater than the 46 mAh g−1 capacity of the non-additive battery. This study offers zinc anode stabilization through high-efficiency electrolyte engineering.

Survey of the multi-stage mass spectrometry of common ionic liquid cations and some polyfluorinated ions

Ionic liquids are useful for many applications and the structural diversity as a class is ever increasing. Knowledge of gas-phase dissociation pathways can inform analytical method development for the characterization of novel syntheses, degradation products, or environmental contaminants, and can inform our knowledge of the fate of ionic liquid species in the gas phase (e.g., after ejection by electrospray spacecraft thrusters). In this work, the N-heterocyclic (NHC) ions:1-butyl-1-methylpiperidinium (BMPi), 1-methyl-1-propylpiperidinium (MPPi), 1-butyl-1-methylpyrrolidinium (BMPyr), 1-ethyl-1-methylpyrrolidinium (EMPyr), 1-butylpyridinium (BPy), and 1-Butyl-1-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl) imidazolium (BFIm) were studied. An additional fluorinated anion, nonafluorobutanesulfonate (NFBS), was also studied. Collision-induced dissociation mass spectrometry (CID-MS), as MS2 and MS3 using an ion trap mass spectrometer and energy-resolved breakdown curves using a quadrupole time-of-flight mass spectrometer, were used to determine dissociation patterns. Assignment of proposed dissociation pathways were made based on the experimental results and complementary computational chemistry. It was observed that for aromatic NHCs, cleavage at the C–N bond was preferred, to generate alkene-based neutral losses. Non-aromatic NHCs typically generated both alkane- and alkene-based neutral losses. Breakdown curves, supported by theoretical thermodynamic calculations, suggest that the loss of the alkane is the favorable dissociation pathway. Additionally, some ring-opening and ring contraction reactions via C–C bond cleavage were observed in non-aromatic species, whereas the intact aromatic NHC is typically a stable terminal ion. The polyfluorinated imidazolium fragmented via the breaking of C–N, C–C, and C–F bonds. The fluorinated anion, NFBS, fragmented by C–C and C–S bond cleavage to generate fluoroalkene, sulfur dioxide, and sulfur trioxide neutral losses. Beyond these broad stroke findings, the dissociation pathways of the seven ionic liquid ions were mapped using evidence from MS3, breakdown curves, and computational chemistry together assigning product ions as either arising from competitive or sequential pathways and proposing tentative structures. Some of the ionic liquid ions showed class-based product ions which will be useful in analytical development for their characterization. Finally, these results were contextualized within previous literature reports on other ionic liquid species.

An Electrochemical Description of 1-Alkyl-3-Methyimidazolium Chloride Ionic Liquids

Three common Ionic Liquids (ILs) were selected 1-Methylimidazolium chloride ([Hmim]Cl), 1-Butyl-3-methylimidazolium chloride ([Bmim]Cl) and 1-Octyl-3-methylimidazolium chloride ([Omim]Cl) for investigation to explore the effects of alkyl chain length and cation protonation on corrosion rate. The aqueous IL solutions have demonstrated a range of identifiably distinct behaviours as a function of changing solution concentration in the range of 70-99.5 mol% water. These behaviours are evidenced by large changes in conductivity, density, and viscosity; these are measurable properties indicating an evolution of hydrogen bonding networks in these systems. These bulk solution properties are critical to the interaction with a metal surface; this was explored using electrochemical testing with Cu and Zn working electrodes. Herein, the focus will be on the use of cyclic voltammetry (at 75 mol%, 85 mol%, 97 mol% and 99.5 mol% water in IL) to describe metal dissolution, deposition, and hydrogen evolution in ILs. The system of equations implemented, to interpret the electrochemical data obtained, have wide-reaching implications in understanding the fundamental behaviours causing observed corrosion behaviours; additionally, the prediction of IL solution conductivity, a vital property for applications of ILs, is of significant value.A kinetic analysis of these solution systems are benefited by the simplicity of the system with no bulk electrolyte, i.e. only the two components: water and IL. Ohmic migration in the bulk and discharge on electrode surface are the two contributions which need to be considered in the Butler-Volmer equation. (n.b. A limitation in the treatment is that thus far no account is taken for the process of solid deposition via a nucleation stage.) In this approximation the following equations can be derived. Each discharging particle must pass two consecutive processes: (1) migration in the field, with characteristic time τohm, and (2) discharge, with the time τBV. The total time will be τtot = τohm + τBV, where τohm -1 = kohm and τBV -1 = kBV. Expressions for Icathodicscan and Ianodicscan results, where φ =E-Ec , for which Ec is the potential at zero current. Two examples are included (Figure 1) to highlight the performance of the models with experimental data. The first case illustrates a particularly good agreement with a cyclic voltammogram experimentally measured for a Cu working electrode in an aqueous-IL solution, the second case is included to demonstrate that the characterstic reversal (near I=0) can be produced. Some deviation, particularly at high current, is likely due to capacitive current. The fitting also gives conductivity, which can be compared and shows good agreement with independent experimental measurements. As such, this successful prediction of the electrochemical behaviours provides an important step in the utilisation of cyclic voltammetry as a method for delivering insight into these two-component IL-containing solutions systems through fundamentally derived expressions. Figure 1

Transport and Energetics of Carbon Dioxide in Ionic Liquids at Aqueous Interfaces.

A major hurdle in utilizing carbon dioxide (CO2) lies in separating it from industrial flue gas mixtures and finding suitable storage methods that enable its application in various industries. To address this issue, we utilized a combination of molecular dynamics simulations and experiments to investigate the behavior of CO2 in common room-temperature ionic liquids (RTIL) when in contact with aqueous interfaces. Our investigation of RTILs, [EMIM][TFSI] and [OMIM][TFSI], and their interaction with a pure water layer mimics the environment of a previously developed ultrathin enzymatic liquid membrane for CO2 separation. We analyzed diffusion constants and viscosity, which reveals that CO2 molecules exhibit faster mobility within the selected ILs compared to what would be predicted solely based on the viscosity of the liquids using the standard Einstein-Stokes relation. Moreover, we calculated the free energy of translocation for various species across the aqueous-IL interface, including CO2 and HCO3-. Free energy profiles demonstrate that CO2 exhibits a more favorable partitioning behavior in the RTILs compared to that in pure water, while a significant barrier hinders the movement of HCO3- from the aqueous layer. Experimental measurement of the CO2 transport in the RTILs corroborates the model. These findings strongly suggest that hydrophobic RTILs could serve as a promising option for selectively transporting CO2 from aqueous media and concentrating it as a preliminary step toward storage.

Environmental Sustainability of π-Electron Donor-Based Deep Eutectic Solvents for Toluene Absorption: A Life-Cycle Perspective.

The novel π-electron donor-based deep eutectic solvents (DESs) have been shown to be a promising type of absorbent with excellent performance on toluene absorption. However, their greenness or sustainability is still unclear. Thus, to bridge the gap and give a comprehensive evaluation for their industrialization potential, the life cycle assessment (LCA) was used to evaluate the potential environmental impacts incurred from their production and usage for absorbing toluene. The environmental profiles are also compared with that of popular choline chloride (ChCl) based DES, common organic solvent triethylene glycol (TEG) and ionic liquid ([EMIM][Tf2 N]). The results indicate that among the involved hydrogen bond acceptors (HBAs), TEBAC generally imparts lower environmental impacts than other HBAs but has higher impacts than ChCl. Although TEBAC-PhOH is not the most environmentally friendly absorbent during the production stage, its outstanding absorption performance minimizes the environmental impact when absorbing the same mass of toluene. Furthermore, the environmental impacts of the toluene absorption process using TEBAC-PhOH is significantly lower than that of [EMIM][Tf2 N], slightly lower than TEG. Therefore, considering both absorption performance and environmental impacts, TEBAC-PhOH can be used as a promising "green and sustainable" toluene absorbent to traditional absorbents and ionic liquids.

Lithium Ion Battery Electrolytes Based on Deep Eutectic Solvents

Deep eutectic solvents (DESs) have emerged as an alternative to both common organic solvents and ionic liquids (ILs). DESs share physicochemical properties with ILs such as low vapor pressure, high thermal stability, while offering advantages such as low toxicity, lower cost, and ease of preparation. Moreover, DESs are attractive candidates for electrochemical applications due to their large voltage windows and solubility properties. DESs as a solvent class share a general composition of a hydrogen bond donor (HBD), typically a polyol, amide, or acid, and a hydrogen bond acceptor (HBA), usually a quaternary ammonium or phosphonium salt. At a specific molar composition of a HBD and HBA, the DES forms a eutectic mixture resulting in a large melting point depression.Despite being widely studied, the microscopic structures of DESs have remained largely uncharacterized. Herein, we present a multitechnique NMR study of ethaline (ethylene glycol + choline chloride). Pulsed field gradient diffusion, nuclear Overhauser effect spectroscopy (NOESY), 13C NMR relaxation experiments are deployed to sample a range of frequencies and modes of motion of the polyol and choline components of the DES. Generally, translational and rotational diffusion of polyols are more rapid than those of choline while short-range rotational motions observed from 13C relaxation indicate slow local motion of ethylene glycol at low choline chloride (ChCl) content.Additionally, we have investigated the solubility properties of several lithium salts (LiTFSI, LiFSI, LiBF4, and LiOAc) in these DESs and utilized the same suite of NMR techniques to understand how they act as solvents. One interesting observation is that the Li+ diffusivity exceeds that of the counterion for TFSI-, but not for FSI-. Finally, large changes in the structural organization of DESs that result from the presence of lithium salts may serve as a guide to the design of a new class of electrolytes for lithium-ion batteries.

Ionic liquids as model systems for the study of the behaviour of electrolytes and surfactants in solutions

Abstract Ionic liquids are among the most studied systems in recent years, and this field is still growing considerably, focusing not only on fundamental research but also on the development of ionic liquids for specific applications. In this paper, the similarities and differences between conventional, “classical” electrolytes and common surfactants and ionic liquids, as well as the surface-active ionic liquids, are discussed to highlight their importance and point out their weaknesses. A brief review of the literature data shows that ionic liquids behave like “classical” electrolytes in solutions and can be described by existing models within the range of their validity. Models that describe concentrated electrolyte solutions well are still lacking, and here ionic liquids, which are less constrained by solubility than ordinary electrolytes, can serve as model systems. The micellization of surface-active ionic liquids in aqueous solutions can be described in the same way as for conventional surfactants, but surface-active ionic liquids offer more opportunities to study specific ion and isomer effects.

Unusual phosphatidylcholine lipid phase behavior in the ionic liquid ethylammonium nitrate

HypothesisThe forces that govern lipid self-assembly ionic liquids are similar to water, but their different balance can result in unexpected behaviour. ExperimentsThe self-assembly behaviour and phase equilibria of two phospholipids, 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), in the most common protic ionic liquid, ethylammonium nitrate (EAN) have been investigated as function of composition and temperature by small- and wide-angle X-ray scattering (SAXS/WAXS) and small-angle neutron scattering (SANS). FindingsBoth lipids form unusual self-assembly structures and show complex and unexpected phase behaviour unlike that seen in water; DSPC undergoes a gel Lβ to crystalline Lc phase transition on warming, while POPC forms worm-like micelles L1 upon dilution. This surprising phase behaviour is attributed to the large size of the EAN ions that solvate the lipid headgroup compared to water changing amphiphile packing. Weaker H-bonding between EAN and lipid headgroups also contributes. These results provide new insight for the design of lipid based nanostructured materials in ionic liquids with atypical properties.

A facile green synthesis of Pd3Cu1 nano-urchins with highly catalytic selectivity for p-nitrobenzaldehyde hydrogenation

Developing a facile green strategy to one-step prepare anisotropic bimetallic nanomaterials with hierarchical structures is preferred choice but remains technically challenge. Here, a simple ionic liquid-directed route is developed for the fabrication of Pd3Cu1 alloy nano-urchins (NUs) at room temperature in aqueous solution. To achieve the synthetic protocol, water-soluble Na2PdCl4 and CuCl2 are used as the initial raw materials, ascorbic acid as the reducing agent, and a common ionic liquid 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) is applied to guide the growth and formation of Pd3Cu1 NUs, vividly demonstrating the green and cost-saving features. The various factors affecting the shapes and sizes of products are researched. The results show that [C4mim]Cl is vital to the formation of thorny Pd3Cu1 NUs. The Pd3Cu1 NUs possess uniform morphology, lots of sharp thorns, high specific surface area and 3D freestanding structures, and exhibit outstanding catalytic activity, selectivity and durability for p-nitrobenzaldehyde hydrogenation having 100% conversion and 94.6% selectivity to p-aminobenzaldehyde. It is believed that the 3D Pd3Cu1 NUs would also have hopeful prospects in electrocatalysis, sensor and beyond.

Process hazard assessment of energetic ionic liquid with kinetic evaluation and thermal equilibrium

With the continuous development of battery technology, there are new research investments in materials of various parts. In the field of electrolytes, ionic liquids (IL) are considered to be excellent electrolytes and have been widely studied in distinct energy fields. However, it is necessary to pay attention to the safety characteristics of ionic liquids at high temperature due to the application of energy, but there is little research on the reaction and kinetics of ionic liquids. To ensure the safety of ionic liquids, such as high temperature, the common ionic liquid 1-Ethyl-3-methylimidazolium nitrate ([Emim] NO3) was selected for analysis. The exothermic mode is obtained from the data of differential scanning calorimetry. The basic reaction parameters of [Emim] NO3 were determined with thermodynamic equation simulation. For ionic liquids in the actual situation, consider adding a heat balance model to estimate its temperature change pattern and find out the hazard temperature and related safety parameters. Temperature changes were estimated by constructing 25.0 g and 50.0 g packages to simulate material reactions and heat transfer in the external environment. The results showed that [Emim] NO3 had shorter TMRad and TCL (<1 day) when the temperature was above 180 °C.

Effect of Electrode Morphology on Performance of Ionic Actuators Based on Vat Photopolymerized Membranes.

Bucky gel electrodes are composed of morphology-determining polyvinylidene difluoride (PVDF) filled with carbon nanotubes (CNT). The electrodes are commonly fabricated via the casting of a CNT dispersion containing PVDF and ionic liquid. In this study, several pore-forming additives such as polyethylene glycol (PEG), dibutyl phthalate (DBP), and the common ionic liquid BMIMBF4 were used to control the morphology of the bucky gel electrodes. The crystalline phase type and content of PVDF in the electrodes were determined by FT-IR and DSC, respectively. SEM revealed a sponge-like structure in the case of the use of BMIMBF4 and a spherulite structure if PEG and DBP were used as additives. A strong influence of morphology on the anisotropic increase in the volume of electrodes upon impregnation with electrolyte was observed. The PEG-based electrode elongated more than the others, while the BMIMBF4-based electrode thickened to a greater extent. Ionic actuators were fabricated to experimentally reveal the effect of electrode morphology on their electromechanical efficiency. A high-precision vat photopolymerization technique was used to fabricate identical ionic membranes and minimize their influence on the properties of the actuators. The electrodes were characterized by the same porosity and electrical capacitance, while the actuators differ significantly in performance. As a result, a simple method of using pore-forming additives made it possible to increase the maximum deformation of bucky gel ionic actuators by 1.5 times by changing the morphology of the electrodes.

Unusual Cation-Pi Solute Interactions with Deep Eutectic Solvents

Deep eutectic solvents (DESs) have emerged as an alternative to both common organic solvents and ionic liquids (ILs). DESs share physicochemical properties with ILs such as low vapor pressure, high thermal stability, high viscosity while offering advantages such as low toxicity, lower cost, and ease of preparation. Moreover, DESs are attractive candidates for electrochemical applications due to their large voltage windows and solubility properties. DESs as a solvent class share a general composition of a hydrogen bond donor (HBD), typically a polyol, amide, or acid, and a hydrogen box acceptor (HBA), usually a quaternary ammonium or phosphonium salt. At a specific molar composition of a HBD and HBD, the DES forms a eutectic mixture resulting in a large melting point depression due to extensive hydrogen bonding between the components.Despite being widely studied, the use and subsequent characterization of DESs as solvents for aromatic phenols and related aromatics has only recently received attention. In this study we have investigated the solubility of a broad class of aromatic solutes as a function of DES composition and solute concentration using 1H, 13C, pulsed field gradient (PFG), and nuclear Overhauser effect (NOE) NMR. The degree to which homogenous mixtures versus heterogeneous and/or multi-phase systems are formed as a function of solute, temperature, and DES composition is examined. Two classes of DESs glyceline (glycerol + choline chloride) and ethaline (ethylene glycol + choline chloride) were investigated.As many as three distinct phases depending on the nature of the aromatic solute are observed by NMR. {1H-1H}-NOESY measurements show strong correlations between the choline chloride ammonium cation and the aryl protons with cation-pi interactions disrupting the hydrogen bonding network of the DES. We will discuss the implications for these systems as green solvents and comment on how clustering of solutes on the nanoscale may find use in catalysis and self-assembly.

(Digital Presentation) Fundamentals of Deep Eutectic Solvents As Electrolytes for Lithium-Ion Batteries

Deep eutectic solvents (DESs) have emerged as an alternative to both common organic solvents and ionic liquids (ILs). DESs share physicochemical properties with ILs such as low vapor pressure, high thermal stability, high viscosity while offering advantages such as low toxicity, lower cost, and ease of preparation. Moreover, DESs are attractive candidates for electrochemical applications due to their large voltage windows and solubility properties. DESs as a solvent class share a general composition of a hydrogen bond donor (HBD), typically a polyol, amide, or acid, and a hydrogen box acceptor (HBA), usually a quaternary ammonium or phosphonium salt. At a specific molar composition of a HBD and HBD, the DES forms a eutectic mixture resulting in a large melting point depression due to extensive hydrogen bonding between the components.Despite being widely studied, the microscopic structures of DESs have remained largely uncharacterized. Herein, we present a multitechnique NMR study of two DESs: glyceline (glycerol + choline chloride) and ethaline (ethylene glycol + choline chloride). Fast-field cycling 1H relaxometry, pulsed field gradient diffusion, nuclear Overhauser effect spectroscopy (NOESY), 13C NMR relaxation, and pressure-dependent NMR experiments are deployed to sample a range of frequencies and modes of motion of the polyol and choline components of the DES. Generally, translational and rotational diffusion of polyols are more rapid than those of choline while short-range rotational motions observed from 13C relaxation indicate slow local motion of glycerol at low choline chloride (ChCl) content. We show how the additional hydroxyl group present in glycerol contributes to not only higher viscosities, but a larger perturbation of the hydrogen bonding network by the addition of ChCl.Additionally, we have investigated the solubility properties of several lithium salts (LiTFSI, LiFSI, LiPF6, LiBF4, and LiOAc) in these DESs and utilized the same suite of NMR techniques to understand how they act as solvents. We observe that due to anion effects, the heterogeneities present in DES result in differential solvation for some species where there is a distinction of lithium salts co-existing in these holes as well as the bulk. The large changes in the structural organization of DESs that result from the presence of lithium salts will serve as a guide to the design of a new class of electrolytes for lithium-ion batteries.