Industrial Application Of Ionic Liquids Research Articles

Revisiting the Advances on Specific Industrial Applications of Ionic Liquids for a Sustainable Green Future – A Review

Revisiting the Advances on Specific Industrial Applications of Ionic Liquids for a Sustainable Green Future – A Review

Purification of Ionic Liquid Solvents in a Self-Optimizing, Continuous Microfluidic Process via Extraction of Metal Ions and Phase Separation

Industrial applications of ionic liquids (ILs)─solvents that can serve as green alternatives to volatile organic compounds─are often hampered by their high cost. Solvent recycling provides a feasible pathway to recover IL solvents to reduce lifecycle costs. Herein, we demonstrate a continuous microfluidic process to purify metal-ion-loaded IL solvents, wherein Fe(III) ions are extracted from a prototypical IL, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM-NTf2), to deionized (DI) water with subsequent membrane separation of the IL and aqueous phases. Inline analytical tools, design of experiment statistical optimization, and a self-optimizing, modified Nelder-Mead simplex algorithm facilitate locating the best parametric operating conditions to optimize both ion extraction and physical phase separation. This process was then adapted to a more challenging purification application: recovery of the IL trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethyl-pentyl)phosphinate (Cyphos 104) from the rare-earth metal Nd(III). This application demonstrated that optimized conditions obtained from a single stage could be applied across a multistage process. Together, these results demonstrate that statistical and inline optimization tools can be used to identify working parameters for different flow systems with a variety of governing fluid properties, for example, viscosity and interfacial tension.

Application Areas of Ionic Hydraulic Fluids

AbstractIonic liquids, as high‐tech technical fluids, have been in practical application in various fields of technology for several years. The search for ionic liquids suitable for use within hydraulic systems, as another new very important field of technology, has taken more than a decade. The development included the identification of material properties important for usage as a hydraulic fluid, an extensive preselection process and laboratory testing of suitable ionic liquids, as well as long‐term testing using real hydraulic components under real operating conditions. Based on the findings, potential areas of industrial application of ionic liquids as hydraulic fluids are presented, which arise from their extraordinary physicochemical properties.

Ferrocene based ionic liquid: synthesis, structure, transport properties and mechanism of thermal degradation

Doping with transition metals is a promising way to expand the industrial applications of ionic liquids (ILs). This study reports the synthesis, structure and physicochemical properties of a novel butyl-dimethyl-(ferrocenylmethyl)ammonium bis(trifluoromethanesulfonyl)imide ([BDFA][NTf2]) IL. The thermo-gravimetric analysis combined with mass spectrometry of evolved gases demonstrated the high thermal stability of [BDFA][NTf2] up to 500 K. The thermal degradation of [BDFA][NTf2] at higher temperatures is a multi-step process accompanied by the cation destruction through the Hofmann elimination reaction and the subsequent transformations, such as fragmentation of the products of thermal degradation of the [NTf2]-anion and the direct interaction between these products. The glass transition and melting temperatures of [BDFA][NTf2] measured by the differential scanning calorimetry are 229 and 320 K, respectively. The electrical conductivities and densities of binary mixtures of [BDFA][NTf2] with acetonitrile (AN) were measured in the temperature range of 293 – 348 K at atmospheric pressure. The isobaric thermal expansion coefficients were calculated from the experimental data. The conductivity – temperature dependences were analyzed using the Arrhenius and Vogel-Fulcher-Tammann equations. The activation energy of ion transport and limiting conductivity increased with the IL mole fraction in AN.

Industrial Applications of Ionic Liquids.

Since their conception, ionic liquids (ILs) have been investigated for an extensive range of applications including in solvent chemistry, catalysis, and electrochemistry. This is due to their designation as designer solvents, whereby the physiochemical properties of an IL can be tuned for specific applications. This has led to significant research activity both by academia and industry from the 1990s, accelerating research in many fields and leading to the filing of numerous patents. However, while ILs have received great interest in the patent literature, only a limited number of processes are known to have been commercialised. This review aims to provide a perspective on the successful commercialisation of IL-based processes, to date, and the advantages and disadvantages associated with the use of ILs in industry.

Quantum chemical calculation, molecular dynamics simulation and process design for separation of heptane - butanol using ionic liquids extraction

Investigating energy-saving and environmentally friendly green solvents is an inevitable requirement for the sustainable development of liquid-liquid extraction. In this work, σ- profiles were drawn using COSMO-SAC model according to the extraction mechanism. Based on quantum chemistry method, the interaction energy, total charge density, deformed charge density and bond length of ionic liquids and butanol were calculated. According to the absolute value of the interaction energy, the hydrogen bond of the total charge density and the deformed charge density, the extractant with good extraction effect can be determined. The radial distribution function of ionic liquids was calculated at the molecular level through molecular dynamics simulation, and the extraction ability of ionic liquids were analyzed. According to the binary interaction parameters obtained from the liquid-liquid equilibrium data of 298.15 K ternary system, the extraction process was simulated. The minimum total annual cost was calculated when the required butanol recovery and heptane purity were achieved. Combining quantum chemical calculation and molecular dynamics simulation to select the best extractant, and verifying the feasibility of ionic liquids as extractant through the simulation process, is of great significance for the industrial application of ionic liquids.

Ionic liquids removal by sequential photocatalytic and biological oxidation

AbstractBACKGROUNDThe industrial application of ionic liquids (ILs) can induce the generation of wastewater and their release into the aquatic media. ILs can be efficiently removed by advanced oxidation processes (AOPs), which are expensive to implement. An alternative, using solar photocatalysis and biological degradation in combination, was used here to remove 1‐hexyl‐3‐methylimidazolium chloride (HmimCl) and 1‐butyl‐4‐methylpyridinium chloride (BmpyrCl). The chemical pretreatment allowed the ILs to be converted into by‐products for easier biodegradation in a sequential batch reactor (SBR).RESULTSPhotocatalytic degradation, using 0.25 g TiO2 L−1 and 600 W m−2 solar radiation for 24 h, allowed a complete ILs removal and a partial mineralization of the organic matter, 28% for Bmpyr+ and 35% for Hmim+. A degradation pathway based on the by‐products identified was proposed for each IL. The reaction effluents were submitted to a biological treatment in an SBR, using organic loading rates of 0.18–0.2 kg COD kg−1 VSS d−1 and a biomass concentration of 3.5 g VSS L−1 in 8 h cycles. The combined treatment allowed highly efficient removal of organic matter [total organic carbon (TOC) conversion exceeded 75% for HmimCl and 78% for BmpyrCl].CONCLUSIONSolar photocatalytic oxidation efficiently removed ILs and produced more biodegradable and less ecotoxic effluents. Biological oxidation increased TOC and chemical oxygen demand (COD) removal to more than 75% for the overall treatment. Combining solar photocatalysis and biological degradation therefore provided an effective system for IL removal. © 2019 Society of Chemical Industry

Osmotic pressure as driving force for recovering ionic liquids from aqueous solutions

An emerging challenge occurs for recovering ionic liquids (ILs) because of their exponential growth in academic and industrial applications. We report for the first time to reclaim water-soluble ILs from their aqueous solutions by osmotically driving water to spontaneously permeate through semi-permeable membranes. Theoretical simulation indicates a weak hydrability of ILs and a tendency to form micelles in water. We thus demonstrate a significant difference in osmotic pressures between the aqueous solutions of ILs and inorganic salts. Four categories of broadly representative ILs are continuously recovered from their diluent aqueous solutions (~1 wt%) with semi-permeable membranes. Eventually, a record-high concentration up to 58–78 wt% is achieved in this work. Our strategy integrates superiorities of low energy consumption, universal applicability toward ILs, diversified selection of semi-permeable membranes, almost unattenuated water flux and high rejection to ions, hopefully providing new insights into the authentic “green” industrial applications of ILs.

The effect of imidazolium and phosphonium ionic liquids on toluene absorption studied by a molecular simulation

Toluene absorption by the ion pairs of 1-butyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([Bmim][TFSI]), 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) and tributyl(propyl)phosphonium tetrafluoroborate ([P4443][BF4]) is performed at the GGA/PW91 level using a density functional theory (DFT). The ion pairs of [Bmim][TFSI], [Bmim][BF4] and [P4443][BF4] are stable with five, five and six hydrogen bonds between the anions and cations, respectively. There is no hydrogen bond and just one C–H⋯π bond between toluene and [Bmim][TFSI], while two hydrogen bonds and three C–H⋯π bonds are formed between absorbed toluene and [Bmim][BF4] or [P4443][BF4]. That shows the interaction between the ion pairs of [Bmim][BF4] and [P4443][BF4] with toluene is stronger than that of [Bmim][TFSI]. Moreover, [P4443]+ has greater effect on the charge transfer of toluene than [Bmim]+ based on the higher electrostatic force with toluene, which indicates that [P4443][BF4] has better advantage on toluene absorption than [Bmim][BF4]. The absorption energy (Eabs, in kJ·mol-1) between toluene and ion pairs of [Bmim][TFSI], [Bmim][BF4] and [P4443][BF4] is −28.88 kJ mol−1, -34.13 kJ mol−1 and -39.38 kJ mol−1, respectively. The frontier molecular orbital (FMO) analysis indicates that absorption of toluene by ionic liquids is a physical process. The HOMO and LUMO of [P4443][BF4]·C7H8 are all localized in toluene, but the LUMO of [Bmim][BF4]·C7H8 is composed by the atoms of imidazolium ring in cation, which also shows that the interaction between toluene and [P4443][BF4] is stronger. In the simulation study, the molecular insight into mechanism of toluene absorption by imidazolium and phosphonium ionic liquids is provided by the comprehension including hydrogen bond, C–H⋯π bonds, electrostatic force and the frontier molecular orbital, which is fundamental for industrial application of ionic liquids in toluene separation.

Numerical modeling for characterization of CO2 bubble formation through submerged orifice in ionic liquids

Industrial applications of Ionic liquids (ILs) in CO2 capture are still limited due to lack of research on CO2-ILs bubble dynamics. A CFD model was developed to understand CO2 bubble formation in the pool of ILs by coupling improved VOF (Volume of Fluid) method with FW–H (Ffowcs Williams and Hawkings) acoustic formulation. Conventional VOF method was improved by adding suitable drag force for CO2-ILs interaction and ILs viscosity was considered as a variable with dissolved CO2. The predicted results are in good agreement with experimental measurements. Based on current CFD model, distinct acoustics pressure signals were examined to characterize CO2 bubble formation stages (growth, necking, detachment). It was investigated that bubble diameter and detachment time were increased with increasing of orifice diameter. Moreover, effects of gas and ILs inlet velocities were explained by fluctuations in Reynolds number and acoustic pressure signals respectively. Higher dissolved CO2 quantity and earlier bubble detachment time were obtained in aqueous ILs than pure ILs. The results have potential to give some useful guidelines to design industrial gas distributor (multiple-holes) for CO2-ILs system.

Speed of Sound and Ultrasound Absorption in Ionic Liquids.

A complete review of the literature data on the speed of sound and ultrasound absorption in pure ionic liquids (ILs) is presented. Apart of the analysis of data published to date, the significance of the speed of sound in ILs is regarded. An analysis of experimental methods described in the literature to determine the speed of sound in ILs as a function of temperature and pressure is reported, and the relevance of ultrasound absorption in acoustic investigations is discussed. Careful attention was paid to highlight possible artifacts, and side phenomena related to the absorption and relaxation present in such measurements. Then, an overview of existing data is depicted to describe the temperature and pressure dependences on the speed of sound in ILs, as well as the impact of impurities in ILs on this property. A relation between ions structure and speeds of sound is presented by highlighting existing correlation and evaluative methods described in the literature. Importantly, a critical analysis of speeds of sound in ILs vs those in classical molecular solvents is presented to compare these two classes of compounds. The last part presents the importance of acoustic investigations for chemical engineering design and possible industrial applications of ILs.

A Mixture of Ionic Liquid and Ethanol Used for Galvanostatic Electrodeposition of CuInxGa1-xSe2 Thin Films

A mixture of 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF4) and ethanol is used for synthesizing CuInxGa1-xSe2 (CIGS) thin films by one-step electrodeposition. The conductivity and electrochemical windows of the mixtures with different volume ratios of ethanol are studied, and Fourier transform infrared spectroscopy spectra are recorded for investigating the interaction between BMImBF4 and ethanol, which indicates that the cations and anions of the ionic liquid interact with ethanol molecule. The electrochemical behaviors of Cu-In-Ga-Se systems are investigated with different ethanol volume fraction. Quantum chemical calculations and molecular dynamic simulations are introduced to study the electronic properties and orbital information of mixtures and electrochemical behaviors of Cu-In-Ga-Se in the mixture. CIGS thin films are characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy in terms of morphology and composition, and by X-ray diffraction and Raman regarding crystal structure. The results show ethanol content has great influences on the electrochemical behaviors of Cu-In-Ga-Se systems as well as the composition and morphology of CIGS thin films. The deposited CIGS thin films are high crystalline quality p-type semiconductor with a bandgap of 1.28 eV after annealed. The mixture can be a promising candidate in industrial application of ionic liquids for electrodeposition of CIGS thin films, even other metals, alloys and semiconductors.

Industrial application of ionic liquids for the recoveries of spent paint solvent

The recovery of industrially valuable organic solvents from liquid waste, generated in chemical processes, is economically crucial to countries which need to import organic solvents. In view of this, the main objective of this study was to determine the ability of selected ionic liquids, namely, 1-ethyl-3-methylimidazolium ethylsulphate, [EMIM][ESO4] and 1-ethyl-3-methylpyridinium ethylsulphate, [EMpy][ESO4] to recover aromatic components from spent paint solvents. Preliminary studies done on the liquid waste, received from a paint manufacturing company, showed that the aromatic components were present in the range of (6–21)% by volume. The separation of the aromatic components was performed with the ionic liquids listed above. The phases, resulting from the separation of the mixtures, were analysed with a gas chromatograph (GC) coupled to a FID detector. Chromatograms illustrate that the chosen ZB-Wax-Plus column gave excellent separation of all components of interest from the mixtures, including the isomers of xylene. The concentrations of aromatics recovered from the spent solvents were found to be in the % ranges of (13−33) and (23–49), respectively for imidazolium and pyridinium based ionic liquids. These results also show that there is a significant correlation between π-character of ionic liquids and the level of extraction. It is therefore concluded that ionic liquids have the potential for macro-scale recovery of re-useable solvents present in liquid waste emanating from paint manufacture.

Regeneration of the ionic liquid tetraoctylammonium oleate after metal extraction

Ionic liquids (ILs) have been presented as suitable candidates for metal extraction in the hydrometallurgy. It has already been proven that they have an adjustable selectivity towards metal ions. However, industrial applications of ILs are often limited due to their high price. Therefore, regeneration and reuse of ILs is necessary. In this study the regeneration of the fatty acid based IL tetraoctylammonium oleate was investigated, because in previous study excellent metal salt extraction efficiencies were obtained with this benign IL. Two methods for regeneration were investigated, i.e. electro-deposition and chemical regeneration. Electro-deposition turned out to be unfeasible for this IL. Chemical regeneration showed that the metal ions (Zn, Co and Mn) can be selectively back-extracted, so that metals can also be separated from each other in this step. The best stripping solution was aqueous sodium oxalate, which allowed the IL to be reused with no further treatment.

Ionic Liquids, Superionic Glasses, Quasi-Ionic Liquids, Quasi-Liquid Ionics, All with High Conductivities but Some with Little Fluidity. Where does the Paradigm End?

Ionic liquids (ILs) are interesting in electrochemistry mainly because of their ability to carry high ionic currents in two distinct cases: (i) for the aprotic class of ILs it is for current flow within a large window of electrochemical stability and hence the support a range of battery electrochemistries[1], and (ii) for the protic class of ILs (PILs) it is for their tunability within a very wide "acidity window"[2]. For case (i), the stability window can extend to almost 6 volts (liquids), and much more at the oxidative end if the liquid has vitrified[3]. The protic ionic liquids are prepared by proton transfer from a Bronsted acid to a Bronsted base, and have been widely studied. Much less well- studied are the "halide-transfer" ionic liquids in which a halide ion is transferred from a halogenated molecular liquid to a strong Lewis acid[4, 5]. Where the proton transfer can be 100% complete in most cases, it is difficult to obtain 100 % halide transfer. In some cases the conductivity is apparently much more complex in nature involving transient oxygen links to the Lewis acid[6]. This means that members of this class of ionic liquid tend to be of low ionicity relative others examined on a Walden plot, although they can still be highly conducting due to their high fluidities. Finally we will discuss some new cases where the conductivity is liquid-like (10 mScm-1), while the system formally has solidified. These are obtained from ionic liquids that have frozen only in the first stage where the centers of mass have become ordered but the rotational and positional order of alkali cations, remains liquid-like[7].[1] J.S. Wilkes, Green industrial applications of ionic liquids. (Editors, R. D. Rogers, K. R. Seddon, and S. Volkov.) (2003) 295-320.[2] C.A. Angell, Y. Ansari, Z.-F. Zhao, Faraday Discussion, 154 (2012) 9-27.[3] A. Hayashi, S. Hama, F. Mizuno, K. Tadanaga, T. Minami, M. Tatsumisago, Solid State Ionics, 175 (2004) 683-686.[4] K. Xu, N.D. Day, C.A. Angell, J. Electrochem. Soc. , 143 (1996) L209-L211.[5] T.G. Tucker, C.A. Angell, (to be published).[6] K. Xu, S.S. Zhang, C.A. Angell, J. Electrochem. Soc. , 143 (1996) 3548-3554[7] T.G. Tucker, C.A. Angell, (to be published), (2014).

Vapor–Liquid Equilibria of Water + Alkylimidazolium-Based Ionic Liquids: Measurements and Perturbed-Chain Statistical Associating Fluid Theory Modeling

The industrial application of ionic liquids (ILs) requires the knowledge of their physical properties and phase behavior. This work addresses the experimental determination of the vapor–liquid equilibria (VLE) of binary systems composed of water + imidazolium-based ILs. The ILs under consideration are 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium thiocyanate, 1-butyl-3-methylimidazolium tosylate, 1-butyl-3-methylimidazolium trifluoroacetate, 1-butyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium methanesulfonate, and 1-butyl-3-methylimidazolium acetate, which allows the evaluation of the influence of the IL anion through the phase behavior. Isobaric VLE data were measured at 0.05, 0.07, and 0.1 MPa for IL mole fractions ranging between 0 and 0.7. The observed increase in the boiling temperatures of the mixtures is related with the strength of the interaction between the IL anion and water. The Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) was further used to describe the obtained experimental data. The ILs were treated as molecular associating species with two association sites per IL. The model parameters for the pure fluids and the binary interaction parameter kij between water and ILs were determined by a simultaneous fitting to pure-IL densities, water activity coefficients at 298.15 K and VLE data at 0.1 MPa. Pure-IL densities, water activity coefficients, and VLE data were well described by PC-SAFT in broad temperature, pressure, and composition ranges. The PC-SAFT parameters were applied to predict the water activity coefficients at infinite dilution in ILs, and a satisfactory prediction of experimental data was observed.

Applications of ionic liquids in organic synthesis and catalysis

In recent years, various novel and greener methodologies have been developed using ionic liquids (ILs). In these reactions, IL has played multiple roles like catalyst, solvent, and catalyst support. In some cases, it was observed that IL enables efficient catalytic reactions in comparison with conventional molecular solvents. On the other hand, although a number of catalytic reaction processes in which ILs are used have been established in industry, there were also some unexpected problems, such as unintelligible aberrance or degradation of so-called task-specific ILs occurring in reaction processes and on the pilot plant scale. Also, several urgent questions regarding the fundamental aspects of ILs particularly toxicity and greener preparation methods need to be clarified. Several industrial applications of ILs are also discussed.

Novel Synthesis of Altretamine and their Process Impurities Using Imidazolium Type of Ionic Liquids

Recent increased awareness of the potentially effects, of organic solvents on environment (air pollution, ozone depletion and global climate change) has led to growth in alternative reaction media. Alternative is Room Temperature ionic liquids (RTILs). Owing to the unique advantages of ionic liquids, and industrial applications of ionic liquids have attracted considerable interest. Herein we report novel synthesis of Antineoplastic (Used for Ovarian Cancer) drug Altretamine and their process impurities using imidazolium based Room-Temperature Ionic Liquid (RTIL).

Novel Synthesis of Bicalutamide Drug Substance and their Impurities using Imidazolium Type of Ionic Liquid

The chemical and pharmaceutical industry is under an accelerating pressure to find environmentally friendly organic reaction methodologies. Owing to the unique advantages of ionic liquids, the preparation and industrial applications of ionic liquids have attracted considerable interest. Herein we report novel synthesis of imidazolium based Room-Temperature Ionic Liquid (RTIL) using cheaper reagents which have been used for the synthesis of Antiandrogenic and Antineoplastic drug Bicalutamide and its impurities reported in US pharmacopoeia.

Recovery of Ionic Liquids with Aqueous Two‐Phase Systems Induced by Carbon Dioxide

Recovery is a very important factor for the industrial application of ionic liquids (ILs). In this work, a novel method is presented for the recovery of ILs by using carbon dioxide (CO₂-induced formation of aqueous two-phase systems (ATPSs). It was found that, in the presence of amines, introduction of CO₂ into aqueous IL solutions leads to the formation of ATPSs at 25 °C and atmospheric pressure, in which the upper phase is ammonium-salt-rich and the lower phase is IL-rich. Thus, the ILs in aqueous solutions can be significantly enriched, and the amines can be regenerated by heating and bubbling Ar or N₂ in the salt-rich phase. To better understand the recovery of ILs, the phase diagrams of the ATPSs were measured at 25 °C, and the effects of the molecular structure of the ILs and the amines and temperature of the systems on the recovery efficiency of the ILs were investigated. It was shown that the single-step recovery efficiency of the ILs could be as high as 99 % in the presence of primary or secondary amines. Therefore, this new method could potentially be sustainable, efficient, and attractive to industry.