Ionic Liquid Forms Research Articles

Glassy gels toughened by solvent.

Glassy polymers are generally stiff and strong yet have limited extensibility1. By swelling with solvent, glassy polymers can become gels that are soft and weak yet have enhanced extensibility1-3. The marked changes in properties arise from the solvent increasing free volume between chains while weakening polymer-polymer interactions. Here we show that solvating polar polymers with ionic liquids (that is, ionogels4,5) at appropriate concentrations can produce a unique class of materials called glassy gels with desirable properties ofboth glasses and gels. The ionic liquid increases free volume and therefore extensibility despite the absence of conventional solvent (for example, water). Yet, the ionic liquid forms strong and abundant non-covalent crosslinks between polymer chains to render a stiff, tough, glassy, and homogeneous network (that is, no phase separation)6, at room temperature. Despite being more than 54 wt% liquid, the glassy gels exhibit enormous fracture strength (42 MPa), toughness (110 MJ m-3), yield strength (73 MPa) and Young's modulus (1 GPa). These values are similar to those of thermoplastics such as polyethylene, yet unlike thermoplastics, the glassy gels can be deformed up to 670% strain with full and rapid recovery on heating. These transparent materials form by a one-step polymerization and have impressive adhesive, self-healing and shape-memory properties.

Preparation of N, S doped Co-Fe/C catalyst derived from ZIF-67/ionic liquid and its catalytic activity for oxygen reduction reaction in alkaline electrolyte

ZIF-67(CoFe) was synthesized using the solvothermal method, and the precursor of ZIF-67(CoFe)/xC-yIL was obtained by grinding the mixture of ZIF-67(CoFe), [BMIM][NTf2] ionic liquid (IL), and carbon black. A series of ZIF-67(CoFe)/xC-yIL-T catalysts were prepared by calcining the precursor at different temperatures. The structure of the catalysts was examined using XRD, TEM, BET and XPS analysis. The results show that the high-temperature treatment of the precursor contributes to the formation of the structure of the N, S-co-doped carbon-coated nanoparticles. The introduction of ionic liquid increases the specific surface area of the catalysts and exposes more active sites. At the same time, as a sulfur source, ionic liquid forms a C-S bond, which is conducive to improving ORR activity. The optimal ORR half-wave potential and limited current density of ZIF-67(CoFe)/1.5 C-45IL-600 are 0.87 V vs. RHE and 4.64 mA cm-2, respectively, in 0.1 mol L−1 KOH.

Combined DFT and ionic model computational study of the effect of alkali metal cations on the structure, bonding and properties of molten cryolites, M3AlF6 (M = li, Na, K, Rb, and Cs)

ABSTRACT Ionic melts, in the form of ionic liquids and molten salts, are important in many technological aspects such as metal production and energy applications. Cryolite melts constitute an important family especially for the industrial production of Al. The present computational study aims to analyse the effect of different cations on the structure and properties of Al (III) fluorocomplexes in cryolite melts. Cation effects are discussed as the ion pair interactions due to alkali metal cations of cryolite compounds M3AlF6 with M= Li, Na, K, Rb, or Cs for various microclusters using ionic interaction model (IM) and DFT calculations. DFT results for different ion complexes are compared with the energy calculations using a pseudoclassical model for isolated clusters. QTAIM and ELF analyses were performed to understand the nature of interactions in detail. A link between open-shell interactions and decreased ionic conductivity is proposed within the series of K, Rb, and Cs. Environmental effects, such as temperature and presence of other ions, are investigated in detail by DFT analysis.

Structure, dynamic, and free energy analyses of 5-hydroxymethylfurfural in aprotic solvents and imidazolium ionic liquids using all-atom molecular dynamics simulations.

5-Hydroxymethylfurfural (5-HMF) is an important chemical generated from lignocellulosic biomass (LCB) to produce a wide variety of value-added chemicals, biofuels, and biochemicals. Different forms of ionic liquids (ILs) have been utilized for the formation of 5-HMF from LCB. However, 5-HMF is highly soluble in imidazolium-based ionic liquids (IMILs), which makes it difficult to separate after its formation from LCB. In this manuscript, we perform all-atom molecular dynamics simulations to investigate the performance of several aprotic solvents in the extraction of 5-HMF from various IMILs. We consider twelve aprotic solvents with different physicochemical properties, such as acetonitrile (AN), acetone (AT), 1,4-dioxane (DI), N,N-dimethyl acetamide (DMA), N,N-dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), gamma-butyrolactone (GBL), gamma-valerolactone (GVL), hexamethylphosphoramide (HMPA), N-methyl pyrrolidone (NMP), propylene carbonate (PC), and sulfolane (SF). We analyze various structures and dynamics and perform a detailed thermodynamic analysis to understand the underlying molecular behavior. The results indicate that solvents AT and DI showed the least favorable interactions with 5-HMF, whereas HMPA showed the most favorable interactions with 5-HMF. Based on the detailed structural insights, HMPA enhances the separation of 5-HMF from the ILs. Furthermore, different anion combinations were tested to benchmark their separation capability. Overall, the results presented in this manuscript guide the selection of solvent and IL combinations for the effective separation of 5-HMF.

Photo-thermal conversion properties of phosphonium-based ionic liquid, its magnetized and emulsion forms

In this work, phosphonium-based ionic liquid (PIL) and its magnetized form (MPIL) were used for heat generation from light. Based on the experimental results, MPIL shows better performance compared to PIL. The MPIL nanofluid was stable even after several consecutive heating/cooling cycles in the closed system. Due to low transparency, the MPIL exhibits the most light-to-heat conversion efficiency on its surface so that the surface temperature respectively reaches 62.5 ℃ and 78.0 ℃ after 60 min simulated light and sunlight irradiation. The photo-thermal conversion ability of the MPIL was examined at various light intensities. Several thermo-physical parameters for PIL and MPIL were calculated and compared, approving the superiority of the MPIL in photo-thermal conversion. To overcome the high cost of large amount of utilized MPIL, which is the drawback of most of ionic liquids, the stable surfactant-free MPIL+Oil emulsion is prepared with a very low amount of MPIL (for the first time), which shows good photo-thermal conversion performance. The outstanding advantages of both MPIL nanofluid and MPIL+Oil emulsion including not using dispersant and high photo-thermal durability/ability make them suitable candidates for practical photo-thermal conversion applications.

In Vitro Antimicrobial Studies of Mesoporous Silica Nanoparticles Comprising Anionic Ciprofloxacin Ionic Liquids and Organic Salts.

The combination of active pharmaceutical ingredients in the form of ionic liquids or organic salts (API-OSILs) with mesoporous silica nanoparticles (MSNs) as drug carriers can provide a useful tool in enhancing the capabilities of current antibiotics, especially against resistant strains of bacteria. In this publication, the preparation of a set of three nanomaterials based on the modification of a MSN surface with cholinium ([MSN-Chol][Cip]), 1-methylimidazolium ([MSN-1-MiM][Cip]) and 3-picolinium ([MSN-3-Pic][Cip]) ionic liquids coupled with anionic ciprofloxacin have been reported. All ionic liquids and functionalized nanomaterials were prepared through sustainable protocols, using microwave-assisted heating as an alternative to conventional methods. All materials were characterized through FTIR, solution 1H NMR, elemental analysis, XRD and N2 adsorption at 77 K. The prepared materials showed no in vitro cytotoxicity in fibroblasts viability assays. The minimum inhibitory concentration (MIC) for all materials was tested against Gram-negative K. pneumoniae and Gram-positive Enterococcus spp., both with resistant and sensitive strains. All sets of nanomaterials containing the anionic antibiotic outperformed free ciprofloxacin against resistant and sensitive forms of K. pneumoniae, with the prominent case of [MSN-Chol][Cip] suggesting a tenfold decrease in the MIC against sensitive strains. Against resistant K. pneumoniae, a five-fold decrease in the MIC was observed for all sets of nanomaterials compared with neutral ciprofloxacin. Against Enterococcus spp., only [MSN-1-MiM][Cip] was able to demonstrate a slight improvement over the free antibiotic.

Development of Edaravone Ionic Liquids and Their Application for the Treatment of Cerebral Ischemia/Reperfusion Injury.

Preparation of the ionic liquid (IL) form of active pharmaceutical ingredients (APIs), termed API-IL, has attracted attention because it can improve upon certain disadvantages of APIs, such as poor water solubility and low stability. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) is a clinically approved cerebroprotective agent against ischemic stroke and amyotrophic lateral sclerosis, while new formulations that enable improvement of its physicochemical properties and biodistribution are desired. Herein, we report a newly developed API-IL of edaravone (edaravone-IL), in which edaravone is used as an anionic molecule. We investigated the physicochemical properties of edaravone-IL and its therapeutic effect against cerebral ischemia/reperfusion (I/R) injury, a secondary injury after an ischemic stroke. Among the cationic molecules used for edaravone-IL preparation, the IL prepared with tetrabutylphosphonium cation existed as a liquid at room temperature, and significantly increased the water solubility of edaravone without decreasing its antioxidative activity. Importantly, edaravone-IL formed negatively charged nanoparticles upon suspension in water. Intravenous administration of edaravone-IL showed significantly higher blood circulation time and lower distribution in the kidney compared with edaravone solution. Moreover, edaravone-IL significantly suppressed brain cell damage and motor functional deficits in model rats of cerebral I/R injury and showed comparable cerebroprotective effect to edaravone. Taken together, these results suggest that edaravone-IL could be a new form of edaravone with superior physicochemical properties and could be useful for the treatment of cerebral I/R injury.

Gallium(III)- and Indium(III)-Containing Ionic Liquids as Highly Active Catalysts in Organic Synthesis.

The chemical industry still requires development of environmentally friendly processes. Acid-catalysed chemical processes may cause environmental problems. Urgent need to replace conventional acids has forced the search for sustainable alternatives. Metal-containing ionic liquids have drawn considerable attention from scientists for many years. These compounds may exhibit very high Lewis acidity, which is usually dependent on the composition of the ionic liquid with the particular content of metal salt. Therefore, metal-containing ionic liquids have found a lot of applications and are successfully employed as catalysts, co-catalysts or reaction media in various fields of chemistry, especially in organic chemistry. Gallium(III)- and indium(III)-containing ionic liquids help to transfer the remarkable activity of metal salts into even more active and easier-to-handle forms of ionic liquids. This review highlights the wide range of possible applications and the high potential of metal-containing ionic liquids with special focus on Ga(III) and In(III), which may help to outline the framework for further development of the presented research topic and synthesis of new representatives of this group of compounds.

High-intensity ultrasound assisted-emulsification using ionic liquids as novel naturally-derived emulsifiers for food industry applications

Over the last decade, conscious food consumption has been revolutionizing the food industry. The search for additives that meet concepts of naturalness, healthiness and sustainability represents one of the major challenges in food industry. The development of emulsifiers in the ionic liquid (IL) form using compounds that can be obtained from natural sources to replace conventional ones is a promising approach. In this work, we have reported the application of bio-based ILs derived from fatty acids (FAs) and choline (Ch) as novel emulsifiers to produce potential food-grade oil-in-water emulsions by pre-mixing (PM) or PM followed by high-intensity ultrasound (HIUS)-assisted process (PM + U). The effects of the type of IL, considering molecular structures of FAs (C18OOH or C18:1OOH) and vegetable oil concentration (30:70 or 70:30, oil:water ratio) to form and stabilize emulsions were evaluated. The study was focused on the following aspects: synthesis and characterization of ILs, and kinetic stability, droplet size and size distribution, optical microscopy, viscosity profile and rheological behavior of the emulsions. ILs presented high emulsifier ability, since some emulsions were stable after storage time of at least 30 days, being such stability related to the type of IL, oil concentration and emulsifying process. The observed behavior was associated to lower droplet size and/or emulsion viscosity. [Ch][C18OO] presented higher emulsifier ability than [Ch][C18:1OO], and this behavior was more evident at higher oil concentration. Emulsions obtained by PM presented phase separation after their preparation, whereas most of those prepared by PM + U were visually stable, being those containing higher oil concentration the formulations that presented higher viscoelasticity, with a gel like behavior. Therefore, bio-based ILs have promising application potential as emulsifiers, and their use to obtain high stable emulsions can be enhanced by using the HIUS technique.

Stimulation of B-Lymphopoiesis by Administration of a Trimecaine-Based Ionic Compound in Cyclophosphamide-Induced Hematopoietic-Depressive Model.

According to the WHO, the secondary form of hematopoietic-depressive status increases the risk of death in people with oncological, infectious, and hormonal diseases. The choice of drugs that stimulate the hematopoietic activity of B-lymphopoiesis is limited. The current leucopoiesis drugs have a number of side effects: thymic preparations stimulate the production of PGE2, which causes chronic inflammation and various autoimmune diseases through the differentiation of T helper 1 (Th1) cells, the proliferation of Th17 cells, and the production of IL-22 from Th22 cells through EP2 and EP4 receptors; cytokine preparations can cause uncontrolled immune reactions and impaired contractility of smooth and cardiac muscles; drugs based on nucleic acids can stimulate the division of all cells, including bacterial and cancerous ones. The use of oligonucleotides such as ribozymes and antisense oligodeoxynucleotides (AS-ODNs) shows promise as therapeutic moieties, but faces a number of challenges such as nuclease sensitivity, off-target effects, and efficient delivery. The search for substances that stimulate B-lymphopoiesis among ionic compounds was motivated by the discovery of the unique properties of lidocaine docusate, one of the first ionic liquid forms of the known drugs. The lidocaine docusate (protonated form of lidocaine (2-(diethylamino)-N-(2,6-dimethylphenyl) acetamide + docusate-anion (dioctylsulfosuccinate))) suppresses the division of pheochromocytoma cells and activates immunity in rats. The trimecaine-based ionic compound (TIC) demonstrates high B-lymphopoiesis-stimulating activity. The TIC compound stimulates an increase in the volume of transitional B cells, which play an important role for further differentiation and formation of a sufficient number of mature B1 cells and mature B2 cells, where mature B2 cells make up the bulk of the functional population of B lymphocytes. The TIC compound most strongly stimulated the restoration of the number of marginal zone B cells, follicular B cells, and activated germinal center B cells after the cytotoxic emptying of the follicular centers of the spleen induced cyclophosphamide. It significantly exceeds the activity of the comparison drug methyluracil. The TIC compound does not affect the level of pro-B, pre-B-I, or pre-B-II bone marrow cells, which prevents the risk of the formation of immature functionally defective cells.

Novel naturally derived encapsulation agents in the ionic liquid form for sustainable emulsion-based products

Naturally derived ionic liquids are efficient encapsulation agents for sustainable emulsion-based products.

Combined Surface Light Scattering and Pendant-Drop Experiments for the Determination of Viscosity and Surface Tension of High-Viscosity Fluids Demonstrated for Ionic Liquids

The present study provides a strategy for the determination of the viscosity and surface tension of high-viscosity fluids in the form of ionic liquids (ILs) at equilibrium conditions by combining surface light scattering (SLS) and the pendant-drop (PD) method within one experimental setup. Through the study of the same sample under identical conditions by both methods inside a closed system, the surface tension determined via the PD method can be directly used to evaluate the dynamics of surface fluctuations of ILs with an overdamped behavior probed by SLS for accessing their viscosity. In connection with the SLS experiments, variations in the applied detection geometries in reflection and transmission direction and in the probed wave vectors down to relatively small values were also addressed. The reliability and self-consistency of SLS and the PD method applied within the same sample cell has been proven by investigating the reference fluids tris(2-ethylhexyl) trimellitate (TOTM) and n-dodecane featuring relatively high and low viscosities. For the two studied model ILs of opaque to non-transparent color, i.e., the hydrophobic 1-methyl-3-octylimidazolium hexafluorophosphate ([OMIM][PF6]) and the hydrophilic 1,3-bis(2-(2-methoxyethoxy)ethyl)imidazolium iodide ([(mPEG2)2Im]I), the combination of PD measurements and SLS experiments in reflection direction performed at ambient pressure between (303 and 373) K allowed access to the viscosity and surface tension with typical relative expanded uncertainties of (4 and 2) %. These results agree well with own viscosity data from capillary viscometry and experimental data in the literature, demonstrating the performance of the novel approach for the contactless in-situ measurement of viscosity and surface tension of fluids with relatively high-viscosity such as ILs.

Polymeric ionic liquid forms of PEI microgels as catalysts for hydrogen production via sodium borohydride methanolysis

• Ionic liquid (IL) forms of polyethyleneimine (PEI) as metal free catalyst for H 2 . • NaBH 4 methanolysis via PEI-X (X:Anion) catalyst for green H 2 production. • Highly reusable IL colloidal polymeric catalyst with low Ea in H 2 generation. • Green energy carrier, H 2 release from NaBH 4 via highly regenerable PEI-X catalyst. Ionic liquid (IL) forms of polyethyleneimine (PEI) microgels were prepared using anion exchange and direct acid treatment techniques employing tetrafluoroborate (TFB) and hexafluorophosphate (HFP) anions as well as their corresponding acids, tetrafluoroboric acid (TFBA) and hexafluorophosphoric acid (HFPA), respectively. Then, these polymeric ionic liquids (PIL) of PEI microgels were used as metal-free catalysts for hydrogen (H 2 ) production from sodium borohydride (NaBH 4 ) solution in methanol (methanolysis). The parameters affecting H 2 production rates such as the types of anions, the methods of PIL preparation, temperature, reusability, and regeneration of PEI-based microgels were investigated. In the dehydrogenation reaction of NaBH 4 in methanol catalyzed by PEI-based PIL microgels, the lowest Ea value in the temperature range of −10–40 °C was calculated as 16.0 ± 0.8 kJ/mol for PEI-HFP PIL microgel, prepared by anion exchange method. The reusability studies of PEI-TFB PIL microgels revealed that the catalytic activity was decreased to 89 ± 5% after 5 consecutive use with 100% conversions for every use. Additionally, independent of the anion exchange methods, PEI-based PIL microgels afford catalytic H 2 production from NaBH 4 methanolysis in a wide range of temperatures including subzero temperatures with facile regenerations by the treatments with TFBA and HFPA resulting in 100% recovery of catalytic activities at each regeneration. The metal-free PIL form of PEI microgel catalyst renders much better catalytic performances and advantages than metal nanoparticle-based catalysts for green H 2 production offering viable alternatives in industrial application.

Impact of the Dicarboxylic Acid Chain Length on Intermolecular Interactions with Lidocaine

Acid–base multicomponent systems have become a popular choice as a strategy to fine-tune the physicochemical properties of active pharmaceutical ingredients. Current prediction tools based on the principles of anticrystal engineering cannot always accurately predict the nature of intermolecular interactions within a multicomponent system. Even small changes in the physicochemical parameters of parent components can result in unexpected outcomes, and many salt, cocrystal, and ionic liquid forms are still being discovered empirically. In this work, we aimed to establish structural consistency in a series of mixtures comprising lidocaine (LID) with decanedioic, undecanedioic, dodecanedioic, and tridecanedioic acids and to explore how length and flexibility of the acid carbon backbone affect the molecular recognition, crystallization, and thermal behavior of the expected binary systems. We found that neat grinding of LID with dicarboxylic acids results in the formation of eutectic phases. The observed eutectic melting points deviated from the ideal eutectic temperatures predicted by the Schroeder van Laar model because of hydrogen bonding between the reacting components within the mixtures. Furthermore, thermal and infrared analysis provided evidence for the possible formation of new phases stemming from partial ionization of the counterions. Besides, the structure of a previously undetermined form I of the tridecanedioic acid was solved by single crystal X-ray diffraction.

Current Drifts in Design and Development of Prodrugs

The design and development of prodrug is based on the objectivity to improve the pharmacokinetic and pharmacodynamic profiles including toxicity of the potent chemical entity. Currently, the prodrug approach is extended with conjugating the parent drug with a self immolating molecule or linker which itself assembles into nanoparticles and prolonged the blood circulation and having passive targeting ability. It also includes delivery of the drug at target site having specific pH condition, delivery of drug to brain by endogenous carrier molecule, NQO1 activable prodrug, prodrug with sustained release behavior, receptor targeted, dual action prodrug, activation via specific enzyme like human carboxylesterase, and phospholipase A2. Some other approaches to prodrug development are that the conversion of active pharmaceutical ingredient (API) into ionic liquids (ILs). In this the biocompatible ionic liquids include choline and amino acid esters are used. One of the anticancer drug methotrexate is formulated into ionic liquid form and used as potential anticancer prodrug. In addition to improvement in combination chemotherapy, there is photoresponsive hybrid prodrug that consists of a photoremovable protecting group. The release of doxorubicin and combrestatin A4 is mainly triggered by 405 nm light and 365 nm light respectively and displayed a quasi-sequential release behavior.

Formation of low melting point binary systems comprising ketoprofen and an amide local anaesthetic

Liquid forms of active pharmaceutical ingredients, ionic liquids (ILs) and deep eutectic mixtures (DEMs), offer several potential benefits in respect to advancing pharmaceutical formulations. The aim of this study was to develop and characterise ILs/DEMs composed of two active molecules: ketoprofen (KET), as the acidic component, and a local anaesthetics (LA), lidocaine (LID), mepivacaine (MEP) or bupivacaine (BUP), which constituted the basic component. A mechanosynthetic approach was successfully applied to obtain LA-KET low melting systems. Composition/temperature phase diagrams were determined by differential scanning calorimetry. The amide LA-KET mixtures showed a eutectic behaviour during heating and formed viscous liquids upon quench cooling. Considering the quench cooled LA-KET mixtures, LA crystallisation was observed only in the LA-rich mixtures. LID, MEP and BUP formed disordered complexes with KET at an approximate 1:2 stoichiometry. Infrared spectroscopy studies revealed that the mixtures were composed mainly of hydrogen bonded acid and base molecules, but small amounts of carboxylate anions were detected. The formation of LA-KET complex not only suppressed the high crystallisation tendency of the LA molecules in the dry state, but also eliminated the crystallisation of KET and LA molecules induced by moisture, as revealed by dynamic vapour sorption studies.

Nanomaterials for Fuel Cell and Corrosion Inhibition: A Comprehensive Review

: A transforming society towards sustainable industrial practices and products chooses to implement “Green Nanomaterial”, with high energy efficiency, minimizing the damage to the environment and exploitation of non-renewable energy resources. A combined overview of recent developments in green nanostructured fuel cells with enhanced durability and activity is presented in this review along with the advancements of green nano materials in the area of corrosion inhibition. : Fuel cells being the next generation ecofriendly energy source, the modification to the solid oxide, microbial and alkaline fuel cell through green nanomaterial are discussed with an emphasis on electrodes, electrolyte, electrode catalysts and membrane components. In addition, the role of green nanomaterial in the form of nano metal oxides, hydroxides, grains, dendrimers, gels, composites, functionalized graphene, halloysite nanotubes and ionic liquids in greening the phenomenon of corrosion inhibition, investigated by various researchers is briefly addressed. : As no single engineered green nanomaterial is emerging as unparalleled and most viable, they are evaluated according to their economic impact, diverse properties, durability and stability. Eventually, these materials with improvement in biocompatibility, solubility, fabrication and handling techniques are predicted to change the environmental and occupational scenario, with some of them already have been found to impact upon the altering global energy needs.

Electrochemical Decomposition of Ethylene Glycol-Choline Chloride Deep Eutectic Solvent

Deep eutectic solvents (DES) are a form of ionic liquid that can offer a larger electrochemical window than water while remaining relatively conductive as compared to other non-aqueous options. DES are made from the eutectic combination of a variety of hydrogen bond donors and acceptors. At a molar ratio of donor and acceptor specific to each DES, the melting point of the mixture is significantly depressed resulting in a room temperature liquid with a high boiling point. As a result, they are considerably less volatile and therefore a safer alternative to traditional organic solvents such as acetonitrile. The low vapor pressure associated with a deep eutectic composition allows for operation at elevated temperatures for faster kinetics, increased conductivity and lower viscosity. DES can also contain a greater concentration of supporting charge carries than many organic solvents (up to 8 M) and many redox active organic compounds are also highly soluble in DES. These factors make DES a promising electrolyte for redox flow batteries, with the potential for higher energy densities than can be achieved in aqueous electrolytes.One of the most commonly studied DES is a 1:2 molar ratio mixture of choline chloride and ethylene glycol respectively. This mixture, commonly called ‘ethaline’ is one of the most conductive, lowest viscosity DES. While these are desirable characteristics, the stable electrochemical window is only ≈2 V which is only somewhat larger than the usable window of an alkaline aqueous electrolyte. The objective of this effort is to investigate the electrochemical decomposition of ethaline at the anodic and cathodic limits.Relatively little literature exists on the decomposition of ethaline. It has been claimed that at the anode, several different chlorinated organics are created by various mechanisms and that hydrogen is evolved at the cathode from water contained in the electrolyte.1 While the oxidation of ethylene glycol (EG) is well studied2 , 3, the oxidation of ethaline and the reduction of EG and ethaline both are somewhat unknown. A series of electrolysis experiments using a divided cell were carried out using dry ethaline prepared in a glove box with a water vapor content below 5 ppm. The water content in the electrolyte was determined by Karl Fischer titration to be less than 300 ppm. The products of these experiments were analyzed using mass spectroscopy (of both the anodic and cathodic electrolytes and of the headspace above each) and FTIR. These results show that the positive decomposition involves the oxidation of ethylene glycol to glycolaldehyde, and subsequent formation of the glycolaldehyde dimer in solution. At the negative limit, hydrogen is evolved in direct proportion to the current passed. However, it can be conclusively shown that the reduction current can exceed the maximum possible current due to the reduction of water, implying that the reduction of the DES components is necessary. GC-MS analysis of the negative electrolyte showed the presence of higher molecular weight fragments consistent with the reaction scheme shown in Fig 1 below. In this scheme, the reduction of ethylene glycol results in the generation of H2 gas as observed, and the formation of ethylene oxide. The ethylene oxide produced then can react chemically with ethylene glycol to yield dimers and trimers of polyethylene glycol whose molecular masses are consistent with the peaks observed in the GC-MS analysis.The identification of these breakdown pathways will provide insight into safety concerns related to overcharge of ethaline electrolytes and will allow for the development of alternative formulations that can extend the potential limits to allow for the incorporation of higher voltage redox couples in redox flow batteries based on DES electrolytes.

Formulation of ionic liquid APIs via spray drying processes to enable conversion into single and two-phase solid forms

Ionic liquid (IL) forms of drugs are increasingly being explored to address problems presented by poorly water-soluble drugs and solid-state stability. However, before ILs of active pharmaceutical ingredients (APIs) can be routinely incorporated into oral solid dosage forms (OSDs), challenges surrounding their ease of handling and manufacture must be addressed. To this end a framework for transforming API-ILs into solid forms at high loadings based on spray encapsulation using an immiscible polymer has recently been demonstrated. The current work demonstrates that this framework can be applied to a broad range of newly synthesized low glass transition temperature (Tg) API-ILs. Furthermore, the work explores a second novel approach to solidification of API-ILs based on polymer-API-IL miscibility that, to the best of our knowledge, has not been previously demonstrated. Modulated differential scanning calorimetry (mDSC) and attenuated total reflectance Fourier transform infrared spectroscopy showed that it was possible to produce spray dried solid materials, at acceptable loadings and yields for OSD applications in the form of both two-phase phase encapsulated systems and single phase amorphous solid dispersions (ASDs). This was achieved by the appropriate selection of an API-IL insoluble polymer (ethyl cellulose) for phase separated systems, or a miscible polymer with an exceptionally high Tg (the polysaccharide, maltodextrin) for the ASDs. Both approaches successfully overcame the Tg suppression associated with room temperature ILs.This work represents the first step to understanding the fundamental critical physical attributes of these systems to facilitate a more mechanistic methodology for their design.

Solvent‐Cast Polymeric Films from Pectin and Eudragit® NE 30D for Transdermal Drug Delivery Systems

In this study, solvent-cast polymeric films containing ionic liquid lidocaine/aspirin for transdermal patches were developed. Solvent-cast polymeric films were prepared from two polymers, pectin and Eudragit® NE 30D, by drying the polymeric solution in a hot air oven at 70 ± 3 °C for 10 h. Glycerin was used as a plasticizer. Lidocaine and aspirin were prepared in ionic liquid form and loaded into the patches. The physicomechanical properties of the films were characterized by texture analysis, differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction. A scanning electron microscope was used to photograph the surfaces of solvent-cast polymeric films. Eudragit® NE 30D significantly decreased the toughness and rigidity of the films. The transdermal patches were in the amorphous state, and their thermal properties were not changed from blank polymeric films. The surfaces of transdermal patches were rougher than blank polymeric films and revealed the distribution of the drug. Eudragit® NE 30D significantly decreased the trends of entrapment efficiency and in vitro release of lidocaine and aspirin drugs. The kinetic release observed in vitro fitted to Higuchi’s model rather than zero and first order models, indicating that a diffusion mechanism governed the release of the drug from the patch. Thus, the solvent-cast polymeric films from two polymers, pectin and Eudragit® NE 30D, are suitable for transdermal patches loaded with ionic liquid lidocaine/aspirin.