Ionic-Liquid-Modified Nanoparticles as Potential Mucus Modulators for Nasal Drug Delivery.

Recent scientific studies are rapidly advancing novel technological improvements and engineering developments that demonstrate the ability to minimize, eliminate, or facilitate the removal of various contaminants and green house gas emissions in power generation. The Integrated Gasification Combined Cycle (IGCC) shows promise for carbon dioxide mitigation not only because of its higher efficiency as compared to conventional coal firing plants, but also due to a higher driving force in the form of high partial pressure. One of the novel technological concepts currently being developed and investigated is membranes for carbon dioxide (CO2) separation, due to simplicity and ease of scaling. A challenge in using membranes for CO2 capture in IGCC is the possibility of failure at elevated temperatures or pressures. Our earlier research studies examined the use of ionic liquids on various supports for CO2 separation over the temperature range, 37°C-300°C. The ionic liquid, 1-hexyl-3methylimidazolium Bis(trifluoromethylsulfonyl)imide, ([hmim][Tf2N]), was chosen for our initial studies with the following supports: polysulfone (PSF), poly(ether sulfone) (PES), and cross-linked nylon. The PSF and PES supports had similar performance at room temperature, but increasing temperature caused the supported membranes to fail. The ionic liquid with the PES support greatly affected the glass transition temperature, while withmore » the PSF, the glass transition temperature was only slightly depressed. The cross-linked nylon support maintained performance without degradation over the temperature range 37-300°C with respect to its permeability and selectivity. However, while the cross-linked nylon support was able to withstand temperatures, the permeability continued to increase and the selectivity decreased with increasing temperature. Our studies indicated that further testing should examine the use of other ionic liquids, including those that form chemical complexes with CO2 based on amine interactions. The hypothesis is that the performance at the elevated temperatures could be improved by allowing a facilitated transport mechanism to become dominant. Several amine-based ionic liquids were tested on the cross-linked nylon support. It was found that using the amine-based ionic liquid did improve selectivity and permeability at higher temperature. The hypothesis was confirmed, and it was determined that the type of amine used also played a role in facilitated transport. Given the appropriate aminated ionic liquid with the cross-linked nylon support, it is possible to have a membrane capable of separating CO2 at IGCC conditions. With this being the case, the research has expanded to include separation of other constituents besides CO2 (CO, H2S, etc.) and if they play a role in membrane poisoning or degradation. This communication will discuss the operation of the recently fabricated ionic liquid membranes and the impact of gaseous components other than CO2 on their performance and stability.« less

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

Ionic systems in materials research : new materials and processes based on ionic polymerizations and/or ionic liquids

Some of the most critical issues facing the nanocomposite community include the need for multi-scale imaging of hierarchical structures, effective methods for controlling nanoparticle chemistry and surface-energy, and efficient processing methods for preparing nanoparticles and nanocomposites. Over the last decade we have employed a number of approaches to address some of these challenges. This paper will review our efforts centered on the use of ionic liquids and fluorescence microscopy to develop tools to enable industry to more quickly bring new nanocomposite-based products to market. Research results focused on polymer nanocomposite based on multiwalled-carbon-nanotube (MWCNT), Montmorillonite (MMT) and nanofibrillated-cellulose (NFC) will be presented.

Although the use of ionic liquids (IL) in polymeric membranes is known to elevate the electrochemical performance for proton exchange membrane-based fuel cells (PEMFC), they suffer from drawbacks such as IL drain and lowering in mechanical properties that lead to deterioration in PEMFC performance. To mitigate these issues, we report, for the first time, the use of polymeric ionic liquid (PIL), namely, poly(diallyl dimethyl ammonium trifluoride methane sulphonate) (P[DADMA][TFMS]) to be blended with polybenzimidazole (PBI-I) as a membrane material for PEMFC. PBI-I and (P[DADMA][TFMS]) were chosen because they form miscible blends and are suitable for acid doping as a matrix, which can eventually be used as proton conductor. The structure, miscibility and inter-polymer interactions were studied by infrared (IR) spectroscopy and differential scanning calorimetry (DSC). The increase in proton conduction in comparison to the PBI membranes was observed due to the presence of ionic groups of PILs in blend membranes. With the increase in PIL content, the proton conductivity of the composite membranes gradually increased from 0.04 S cm−1 for PBI to 0.07 S cm−1 for the blend membrane at 150 °C. The MEAs were fabricated with PBI-I, PBI-PIL15, PBI-PIL25 and PBI-PIL35. Corresponding single cells were successfully tested at temperatures of 160 °C. The maximum power density and current density obtained were 515 mW cm−2 and 1632 mA cm−2, respectively, for PBI-PIL25-based MEA.

The diversity and intensity of ionic liquid (IL) research in the Australasian region has mirrored that worldwide, as these unique materials move from simply being conceptually interesting, to valuable commodities for many different areas of application. The presentations in the 5th Australasian Symposium on Ionic Liquids (ASIL-5) reflected the variety of research in the field and highlighted the exciting promise of ILs in applications ranging from electrochemistry to green chemistry, corrosion resistance to pharmaceutical salts. The fifth in the series of the very successful AustralasianSymposium on IonicLiquidswas held on the3rd–4th May 2012 in Clayton, Australia. The symposium was co-hosted by theARCCentre of Excellence for Electromaterials Science at Monash University, CSIRO and the Monash Ionic Liquids group. The symposiumwas initiated in 2003 and has remained a magnet for world-leaders in the field as well as a friendly forum for young students and researchers to present their work. International speakers at ASIL5 included Professor Hiroyuki Ohno, Tokyo University of Agriculture and Technology, Professor Frank Endres, Clausthal University of Technology, Professor Suojiang Zhang, Chinese Academy of Sciences, Professor EdwardMaggin, University of Notre Dame, Professor Toshiyuki Itoh, Totteri University, and Professor Sergey Verevkin, University of Rostock. The symposium also featured speakers from CSIRO and a range of Australian universities including Curtin University, Deakin University, Monash University, the University of Newcastle, the University of New South Wales, and the University of Sydney. Contributions from an invited selection of speakers are presented here, in this special IL issue of the Australian Journal of Chemistry – an International Journal for Chemical Science. The electrochemical applications of ILs have always been one of the leading interests in the field, particularly their use for electrodeposition and battery applications. Endres and coworkers, have shown that polycarbonate templates can be used within a chloroaluminate-based IL for the electrodeposition of aluminium nanowire electrodes. These electrodes show promising properties for use as anodes in lithium ion batteries, with good mechanical stability after 50 cycles in an IL-based electrolyte. Additives within chloroaluminate-based ILs can also influence the nucleation process, morphology, and crystallinity of aluminium electrodeposits, as reported by Zhang et al. Endres and coworkers also show that lithium can be deposited onto copper electrodes modified with polystyrene sphere opals, using an air and water stable IL-based medium, producing lithium either as hollow spheres or with a macroporous structure. This work highlights the complex nature of electrodeposition from ILs, and also points the way towards high surface area lithium electrodes that could be useful for rechargeable lithium metal micro-batteries. The use of ILs in lithium metal batteries is attracting increasing interest, particularly from a safety perspective as many ILs are non-flammable. One important aspect of this research involves understanding any chemical reaction between the lithium metal and the IL, normally assessed during or after cycling the battery. A novel approach is discussed here by Bhatt and coworkers, who report a significant influence of storage time on the morphology and performance of lithium electrodes in an IL/lithium salt medium. This indicates that for use of ILs in practical battery applications, the periods when the battery is not in use may also impact the performance.

This chapter reviews the roles of ionic liquids (ILs) in pharmaceutical manufacturing processes, including the use of ILs as solvents in the synthesis of drugs or isolation of drug intermediates, the use of ILs in pharmaceutical crystallization, in pharmaceutical separation, for the extraction of drugs from natural products, to deliver drugs, to detect drugs, and even as active pharmaceutical ingredients (APIs). ILs have also been considered as alternatives to organic solvents in the pharmaceutical industry. A large volume of volatile organic solvents (VOCs) is used in the process of drug extraction from natural products, resulting in serious environmental problems and replacement of conventional solvents by ILs might prevent the emission of VOCs. While ILs have been shown to be efficient vehicles in transdermal drug delivery, until recently they were not studied as transdermal drugs themselves because ionized salts normally diffuse poorly through lipid membranes.

PurposeThe use of ionic liquids (ILs) in drug delivery has focused attention on non-toxic IL counterions. Cationic lipids can be used to form ILs with weakly acidic drugs to enhance drug loading in lipid-based formulations (LBFs). However, cationic lipids are typically toxic. Here we explore the use of lipoaminoacids (LAAs) as cationic IL counterions that degrade or digest in vivo to non-toxic components.MethodsLAAs were synthesised via esterification of amino acids with fatty alcohols to produce potentially digestible cationic LAAs. The LAAs were employed to form ILs with tolfenamic acid (Tol) and the Tol ILs loaded into LBF and examined in vitro and in vivo.ResultsCationic LAAs complexed with Tol to generate lipophilic Tol ILs with high drug loading in LBFs. Assessment of the LAA under simulated digestion conditions revealed that they were susceptible to enzymatic degradation under intestinal conditions, forming biocompatible FAs and amino acids. In vitro dispersion and digestion studies of Tol ILs revealed that formulations containing digestible Tol ILs were able to maintain drug dispersion and solubilisation whilst the LAA were breaking down under digesting conditions. Finally, in vivo oral bioavailability studies demonstrated that oral delivery of a LBF containing a Tol IL comprising a digestible cationic lipid counterion was able to successfully support effective oral delivery of Tol.ConclusionsDigestible LAA cationic lipids are potential IL counterions for weakly acidic drug molecules and digest in situ to form non-toxic breakdown products.

Review: 122 refs.

In recent years, with the development of micro/nanoelectromechanical systems (MEMS/NEMS), the demand for efficient lubricants of silicon surfaces intensified. Although the use of ionic liquids (ILs) as additives to base oils in the lubrication of steel/steel or other types of metal/ metal tribological pairs has been investigated, the number of studies involving Si is very low. In this work, we tested imidazolium-based ILs as additives to the base oil polyethylene glycol (PEG) to lubricate Si surfaces. The friction coefficients were measured in a nanotribometer. The viscosity of the PEG + IL mixtures as well as their contact angles on the Si surface were measured. The topography and chemical composition of the substrates surfaces were determined with atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. Due to the hygroscopic properties of PEG, the first step was to assess the effect of the presence of water. Then, a series of ILs based on the cations 1-ethyl-3-methylimidazolium [EMIM], 1-butyl-3-methylimidazolium [BMIM], 1-ethyl-3-vinylimidazolium [EVIM], 1-(2-hydroxyethyl)-3-methylimidazolium [C2OHMIM] and 1-allyl-3-methylimidazolium [AMIM] combined with the anions dicyanamide [DCA], trifluoromethanesulfonate [TfO], and ethylsulfate [EtSO4] were added to dry PEG. All additives (2 wt %) led to a decrease in friction coefficient as well as an increase in viscosity (with the exception of [AMIM][TfO]) and improved the Si wettability. The additives based on the anion [EtSO4] exhibited the most promising tribological behavior, which was attributed to the strong interaction with the Si surface ensuring the formation of a stable surface layer, which hinders the contact between the sliding surfaces.

Perspective on ionic liquids and ionic liquid membranes

Dilute sulfuric acid and acidic ionic liquids are pretreatment methods used to selectively hydrolyze hemicellulose from lignocellulosic biomasses. In this work, a comparison between these techniques is carried out by treating sugarcane bagasse both with 1-ethyl-3-methylimidazolium hydrogen sulfate at different ionic-liquid and water contents and with H 2 SO 4 at the same conditions and equivalent ionic liquid molar contents. Results from the use of ionic liquid showed that it was possible to tune the biomass treatment either to achieve high hemicellulose hydrolysis yields of 72.5 mol% to very low furan and glucose co-production, or to obtain furfural at moderate yields of 18.7 mol% under conditions of low water concentration. In comparison to the use of ionic liquid, sulfuric acid pretreatment increased hemicellulose hydrolysis yields by 17%, but the 8.6 mol% furfural yield was also higher, and these yields were obtained at high water concentration conditions. Besides, no such tuning ability of the biomass treatment conditions can be made.

Chemical flooding process has shown great potential in Enhanced Oil Recovery (EOR).Unfortunately, chemicals used have some disadvantages such as high cost, high toxicity and high adsorption tendency.In this study, we aim at using Ionic Liquids (ILs) as alternatives for traditional chemicals.Ionic liquids are salts having melting point below 100°C and they found as a liquid at room temperature.Nine Ammonium and Phosphonium based ILs were screened.The screening was based on their solubility in brines of different compositions, thermal stability and ability to reduce the aqueous-oleic phase's Interfacial Tension (IFT).The screening process flagged Ammoeng 102 as the favored ionic liquid.More investigations of Ammoeng 102 solutions indicated a sharp exponential decrease of IFT values with increasing concentration.On contrary to surfactant solutions, Lower IFT values were obtained with increasing brine salinity indicating the ILs superiority in high salinity reservoirs.Two tertiary flooding experiments were conducted using 500 ppm Ammoeng 102 diluted in 10% and 20% (w/w) brine salinity to investigate its recovery efficiency.Lower salinity secondary brine flooding provided higher recovery.The opposite trend occurred in tertiary ionic solution flooding where recovery is higher for high salinity ionic solution indicating the effectiveness of ILs in recovering oil in high salinity, high temperature environment.In addition, the low cost and low toxicity are more advantages to promote the use of Ionic liquids in future EOR processes.

Ionic liquids in electrokinetic chromatography

Extraction of organic compounds involved in the kinetic resolution of rac-2-pentanol from n-hexane by imidazolium-based ionic liquids: Liquid-liquid equilibrium