Magnetic Ionic Liquid Research Articles

PIM-1 mixed matrix membranes incorporated with magnetic responsive cobalt-based ionic liquid for O2/N2 separation

Membrane technology for O2/N2 separation is a mature industrial unit. Membranes with excellent permeation-separation performance are still one of the critical requirements. The cobalt-based compounds have been well known for their good affinity for O2, which can facilitate O2 transfer and improve the O2/N2 selectivity in membranes. The cobalt-based compounds, moreover, have a magnetic responsive effect, which can lead to a further improvement in O2/N2 separation under a magnetic field. A class of PIM-1 mixed matrix membranes (MMMs), containing cobalt-based ionic liquid (CILs)@polyarylate (aromatic polyester) (PAR) (core-shell) composite nanospheres (CILs@PAR (c-s) CNPs), were prepared. Chemical compositions of CILs@PAR (core-shell) CNPs were determined by Fourier transform infrared spectroscopy (FTIR). Morphologies and structures of CILs@PAR (core-shell) CNPs were observed by transmission electron microscopy (TEM). Gas adsorption properties of CILs@PAR (core-shell) CNPs were tested. Thermal properties of the (CILs@PAR (c-s) CNPs)/PIM MMMs were investigated by simultaneous thermal analysis (TGA-DSC). Gas permeation-separation performances of the (CILs@PAR (c-s) CNPs)/PIM MMMs were also reported. Compared with the original PIM-1 membrane, the (CILs@PAR (c-s) CNPs)/PIM MMMs display higher O2/N2 selectivity because of cobalt-based ionic liquid as O2 carrier, coupled with a reduction in O2 permeability. With increasing the content of the CILs@PAR (c-s) CNPs, the O2/N2 selectivity increases, and the O2 permeability decreases. It is also found that, as a magnetic field on the MMMs, the O2/N2 selectivity further increases; and it increases more, as a higher content of CILs@PAR (c-s) CNPs. Therefore, the (CILs@PAR (c-s) CNPs)/PIM MMMs exhibit excellent O2/N2 selectivity of ∼5 coupled with good O2 permeability of ∼140 Barrer under a 180 mT magnetic field and show great potential for air separation.

Investigating the Structural, Electronic, and Topological Properties of [BMIm][Fe(NO)2Cl2] Magnetic Ionic Liquid: Density Functional Theory Approaches

Magnetic ionic liquids (MILs) show clear superiority over conventional ionic liquids suitably nested in many applications, particularly in medicine and drug delivery engineering. The easy way of collecting them using an external magnet and separating them from the reaction mixture is a favorable and unique technique. A magnetic imidazolium-based IL, including iron coordinated with -NO and chloride ligands ([BMIm][Fe(NO)2Cl2]) (BMIm = 1-n-butyl-3-methyl-imidazolium), has been studied using density functional theory. Such dinitrosyl iron compounds are significant as NO-saving sources and carriers because of their longer physiological lifetime compared with molecular NO. The dependability of the calculations was examined and elucidated at three different methods (M06-2X, B3LYP, and B3LYP-D3) to unravel the importance of noncovalent interactions, including dispersion and H-bonding. Also, the effect of a large basis set on different features of this MIL was assessed. This research is a pioneer in theoretically characterizing the type of -NO moiety of this open-shell dinitrosyl iron compound. The complicated structure of the dinitrosyliron unit was determined by the geometrical parameters, stretching frequencies, and magnetic moment calculation. Based on these fingerprint data, the predominant form of two NO's in this MIL is the nitroxyl anion NO-, rather than ṄO or NO+. Unraveling that one of the NO ligands structurally is dangling enhances the application of this MIL as a NO-saving and source compound. Consequently, Fe3+ is identified as the major oxidation state of the iron atom, leading to the MIL with a strong magnetic moment (of 5.22μB).

Dual-responsive imidazolium-based ionic liquid with different alkyl chains as draw solutes for forward osmosis

Imidazolium-based magnetic ionic liquids (MILs) with dual responsiveness, a series of 1-alkyl-3-methylimidazolium tetrachloroferrates (Cn-FeCl4, n = 4, 8, and 12, where n denotes the number of carbon atoms in the alkyl group of 1-alkyl-3-methylimidazolium), were synthesized to assess their ability as smart draw solutes for forward osmosis (FO). The recovery properties and FO performance of Cn-FeCl4 were investigated extensively. This series of Cn-FeCl4 exhibits lower critical solution temperature (LCST) characteristics and paramagnetic behavior in the magnetization curve as a function of the magnetic field, which minimizes the energy consumption for recovering draw solutes from spent draw solutions. The LCSTs of the C4-FeCl4, C8-FeCl4, and C12-FeCl4 draw solutions at a concentration of 20 wt % were approximately 76, 43, and 55 °C, respectively. The respective calculated magnetic susceptibilities of MILs were 5.92 × 10−5, 4.53 × 10−5, and 4.12 × 10−5 emu cm−3 at 300 K. Moreover, when the concentration of the draw solution was 20 wt %, the water flux of C8-FeCl4 was approximately 17.30 LMH and 10.04 LMH in active layer facing draw solution and active layer facing feed solution modes, respectively. Subsequently, in desalination applications, C8-FeCl4 exhibited feasibility in saline water with 2000 and 30,000 ppm NaCl. Therefore, for the first time, we studied the effect of the structural transformation of MILs on draw solute properties and examined the applicability of magnetic and thermal dual-responsive MILs as draw solutes for FO processes.

Asymmetric anion effects of anions in ionic liquids: Crystal polymorphs and magnetic properties

In this study, the phase transitions and magnetic properties of magnetic ionic liquids (mILs) were investigated at low temperatures. The mILs were [Cnmim]2[MnCl4-mBrm] (n = 2, 3, and 4; m = 0, 1, 2, 3, and 4), where [Cnmim]+ is 1-alkyl-3-methylimidazolium. Here, simultaneous X-ray diffraction and differential scanning calorimetry were used to determine the crystal polymorphs in the mILs. The results showed that shorter alkyl chain lengths of cations and symmetric anions aided crystallization. Melting points in [C2mim]2[MnCl4-mBrm] were also found to be strongly dependent on asymmetric anionic configurational and cationic conformational entropies. Furthermore, the asymmetric anion effect contributed slightly to the paramagnetic properties of mILs.

A microwave-assisted extraction method combined with magnetic ionic liquid-based dispersive liquid-liquid microextraction for the extraction of chloramine-T from fish samples prior to its determination by high-performance liquid chromatography.

In the present work, a combination of microwave-assisted extraction with magnetic ionic liquid-based dispersive liquid-liquid microextraction was developed for the extraction of chloramine-T from fish samples. In this method, the sample was mixed with a hydrochloric acid solution and exposed to microwave irradiations. By doing so, chloramine-T was converted to p-toluenesulfonamide and extracted from the sample into an aqueous phase. Then, a mixture of acetonitrile (as a dispersive solvent) and magnetic ionic liquid (as an extraction solvent) was rapidly injected into the obtained solution. In the following, the magnetic solvent droplets including the extracted analytes were isolated from the aqueous solution in the presence of an external magnetic field and after diluting with acetonitrile injected into high-performance liquid chromatography equipped with a diode array detector. Under the optimum extraction conditions, high extraction recovery (78%), low limits of detection (7.2ng/g) and quantification (23.9ng/g), good repeatability (relative standard deviations ≤5.8 and 6.8% for intra- and inter-day precisions, respectively), and wide linear range (23.9-1000ng/g) were obtained. Finally, various fish samples marketed in Tabriz city (East Azarbaijan, Iran) were analyzed with the suggested method.

Magnetic ionic liquid 1-ethyl-3-methylimidazolium tetrachloroferrate characterized by XPS

The XPS spectra of ionic liquid 1-ethyl-3-methylimidazolium tetrachloroferrate (EmimFeCl4) were collected with Al Kα x-radiation, and the result provides a valence band spectrum in addition to the core Fe 2p, Cl 2p, and C 1s spectra.

Magnetically-separable quasi-homogeneous catalyst: Brush-type ionic liquid polymer coated magnetic polymer microspheres for tandem reactions to produce 4H-pyrans/biodiesel

Employing magnetic polystyrene microspheres as the core and brush-type alkaline imidazolium ionic liquid polymers as the covalent bonds, a robust magnetically-separable quasi-homogeneous magnetic brush-type ionic liquid polymers ([Im][OH]/MP-B) was synthesized. Due to the features of brush-type ionic liquid polymer (BILPs), [Im][OH]/MP-B demonstrated high catalytic activity. With a broad variety of substrates, [Im][OH]/MP-B was applied in Knoevenagel-Michael tandem reactions for the synthesis of 4 H-pyrans (achieving 99.99% conversion and 93.6% yield) and transesterification tandem reactions for sustainable biodiesel production (achieving 99.9% conversion and 95.2% yield). Furthermore, the catalytic performance of [Im][OH]/MP-B was superior to that of [Im][OH]/MP-CL and [Im][OH]/MP-L and comparable with that of homogeneous catalysts. The reasonable and feasible reaction mechanism of magnetic ionic liquid polymers catalyzing tandem reactions was explored in-depth based on the catalytic performance and kinetics, which clearly demonstrated the catalytic activity and stability of [Im][OH]/MP-B. Notably, [Im][OH]/MP-B was effortlessly recovered by magnetic separation and reutilized numerous times with no evident change in catalytic performance, composition, or microstructure, indicating promising possibilities for ecologically friendly procedures. This work provides a potential strategy for the synthesis of magnetic BILPs for tandem reactions, which could serve as a platform for ecologically friendly and sustainable chemistry.

Faraday effect and refractive index of some imidazolium-based room-temperature ionic liquids and magnetic ionic liquids

Knowledge of the Faraday effect (FE) is very important in fundamental research and applications. Here, we report FE and refractive index studies for two magnetic ionic liquids (MILs), namely 1-ethyl- and 1-butyl-3-methylimidazolium tetrachloroferrate. Similar studies are also conducted for ionic liquids (ILs) that have a diamagnetic counteranion in place of [FeCl4]. The magnitudes of the Verdet constants of MILs are comparable and exhibit a negative sign. Furthermore, they are about one order larger than those of ILs with a diamagnetic counteranion of a positive sign. The Verdet constant shows monotonic variations as a function of wavelength in the range from 450 to 650 nm and is mainly related to charge transfer transitions in [FeCl4], with bands located in the UV region, though the contribution of d-d transitions in Fe+3 is negligible. A model for describing the measured Verdet constant data as a function of wavelength and temperature is given with respective values of effective Faraday A-, B-, and d-terms. The introduction of an empirical rule allows the estimation of Verdet constants of iron and imidazolium derivative based MILs, which are in some cases very high, thus indicating their potential in photonics applications. Imidazole shows a positive and nearly-two orders lower magnitude of the Verdet constant. The mixture of an MIL and acetonitrile allows the tuning of both the Verdet constant and the refractive index. The refractive indices, thermo-optic coefficients, and electronic polarizabilities of MILs are higher than those of ILs with a diamagnetic counteranion.

Dual role of magnetic ionic liquid in EMI absorbing polymer composites of P(VDF-TrFE) and f-MWCNTs

Dual role of magnetic ionic liquid in EMI absorbing polymer composites of P(VDF-TrFE) and f-MWCNTs

Isolation of DNA from plant tissues using a miniaturized matrix solid-phase dispersion approach featuring ionic liquid and magnetic ionic liquid solvents

The isolation of high-quality plant genomic DNA is a major prerequisite in many plant biomolecular analyses involving nucleic acid amplification. Conventional plant cell lysis and DNA extraction methods involve lengthy sample preparation procedures that often require large amounts of sample and chemicals, high temperatures and multiple liquid transfer steps which can introduce challenges for high throughput applications. In this study, a simple, rapid, miniaturized ionic liquid (IL)-based extraction method was developed for the isolation of genomic DNA from milligram fragments of Arabidopsis thaliana plant tissue. This method is based on a modification of vortex-assisted matrix solid-phase dispersion (VA-MSPD) in which the trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide ([P6,6,6,14+][NTf2-]) IL or trihexyl(tetradecyl)phosphonium tris(hexafluoroacetylaceto)nickelate(II) ([P6,6,6,14+][Ni(hfacac)3-]) magnetic IL (MIL) was directly applied to treated plant tissue (∼1.5 mg) and dispersed in an agate mortar to facilitate plant cell lysis and DNA extraction, followed by recovery of the mixture with a qPCR compatible co-solvent. This study represents the first approach to use ILs and MILs in a MSPD procedure to facilitate plant cell lysis and DNA extraction. The DNA-enriched IL- and MIL-cosolvent mixtures were directly integrated into the qPCR buffer without inhibiting the reaction while also circumventing the need for additional purification steps prior to DNA amplification. Under optimum conditions, the IL and MIL yielded 2.87 ± 0.28 and 1.97 ± 0.59 ng of DNA/mg of plant tissue, respectively. Furthermore, the mild extraction conditions used in the method enabled plant DNA in IL- and MIL-cosolvent mixtures to be preserved from degradation at room temperature.

Thermoresponsive magnetic ionic liquids as forward osmosis draw solutes for seawater desalination

Thermoresponsive magnetic ionic liquids (TMILs) showing lower critical solution temperature (LCST)-behavior were fabricated and utilized as forward osmosis (FO) draw solutes for seawater desalination. The MILs, 8-alkyl-1,8-diazabicyclo[5.4.0]undec‑7-ene bromotrichloroferrate (DBU-R[FeBrCl3], or d-R-FeX4) with different alkyl chain lengths (R = C4H9, C6H13, C7H15, or C8H17), exhibited tunable LCSTs from 30 to 65 °C by varying the chain length and the solution concentration. Upon heating above their LCSTs, more than 43% of the TMILs could be magnetically extracted via phase separation, demonstrating a facile magnet-assisted draw solution regeneration approach. In addition, an aqueous solution containing 25 wt% D-Bu-FeX4 was able to achieve a water flux as high as 4.5 L m−2h−1 (LMH) in desalinating seawater. Their ionic nature, together with unique thermo- and magnetic-responsive behaviors, make them promising candidates as ideal FO draw solutes for desalination and wastewater reclamation.

An affordable and semiautomated approach as a novel strategy for the extraction of DNA using magnetic ionic liquids followed by real time-polymerase chain reaction.

This technical note describes a novel and straightforward experimental strategy for the extraction/capture of DNA using magnetic ionic liquid (MIL) followed by real time-polymerase chain reaction (qPCR) analysis. An affordable and low-cost magneto-based multiwell platform was first examined for capturing DNA allowing for simultaneous extractions that increased the analysis throughput of the experimental workflow. This configuration was composed of a series of neodymium rod magnets attached to a multiwell device in which a magneto-active extraction phase (MIL) was suspended for a single drop microextraction (SDME) approach. In this configuration, up to 32 extractions were able to be performed simultaneously, and DNA was successfully extracted from aqueous samples. Furthermore, as a proof-of-concept, this affordable and simple experimental strategy proved to be efficient for the extraction/capture of DNA from challenging samples such as whole blood without any pretreatment. This fact also consists of important feature compared to previous methodologies that required additional steps of sample preparation.

Physico-Chemical Properties of Magnetic Dicationic Ionic Liquids with Tetrahaloferrate Anions.

A series of imidazolium-based symmetrical and asymmetrical dicationic ionic liquids (DcILs) with alkyl spacers of different length and with [FeCl3 Br]- as counter ion have been synthesized. The synthesized DcILs are characterized by using FTIR and Raman spectroscopy as well as mass spectrometry, along with single-crystal XRD analysis. Physicochemical properties such as solubility, thermal stability and magnetic susceptibility are also measured. These compounds show low melting points, good solubility in water and organic solvents, thermal stability, and paramagnetism. The products of molar susceptibility and temperature (χmol ⋅T) for the synthesized DcILs have been found between 4.05 to 4.79 emu mol-1 K Oe-1 and effective magnetic moment values have also been determined to be compared to that expected from the spin-only approximation.

Removal of Cd(II) ion from aqueous solution using magnetic ionic liquid based nanocomposites [NiFe2O4@BMSI]Br: kinetics, isotherm and thermodynamic studies

Removal of Cd(II) ion from aqueous solution using magnetic ionic liquid based nanocomposites [NiFe2O4@BMSI]Br: kinetics, isotherm and thermodynamic studies

Multi-magnetic center ionic liquids for dispersive liquid-liquid microextraction coupled with in-situ decomposition based back-extraction for the enrichment of parabens in beverage samples

In this paper, several new multi-magnetic center magnetic ionic liquids (MMILs) were prepared with paramagnetic component simultaneously contained in both the cation and anion and used as extractants to establish a dispersive liquid-liquid microextraction (DLLME) approach followed by in-situ MMIL decomposition based back-extraction for the enrichment and determination of four parabens in beverages. The appropriate MMIL was selected by investigating the extraction performances of the obtained MMILs combined with high performance liquid chromatography-ultraviolet detection (HPLC-UV), and some other experimental factors were explored. Under the optimized DLLME conditions, the four parabens exhibited coefficients of determination (R2) above 0.9987 in the linear range of 0.1-500 ng·mL−1 for ethylparaben, propylparaben and butylparaben and 0.2-500 ng·mL−1 for methylparaben. The limits of detection (LODs) and limits of quantification (LOQs) were respectively within 0.03-0.06 ng·mL−1 and 0.1-0.2 ng·mL−1, and the relative standard deviations (RSDs) for intra-day and inter-day precision were below 10.8%. Moreover, the application of the developed MMIL-based DLLME method in beverage samples exhibited recoveries within 81.3%-112.1% with RSDs of 0.3%-13.1% at three different spiked levels.

Functionalized aqueous biphasic system coupled with HPLC for highly sensitive detection of quinolones in milk

Two PPG1000 based thermo-sensitive magnetic ionic liquids were synthesized and characterized. A novel analytical method of thermo-sensitive magnetic ionic liquid aqueous biphasic system coupled with HPLC was employed for the successive enrichment and highly sensitive detection of trace amount of quinolones in milk for the first time. It has realized successive enrichments in an analytical method for the first time. High enrichment factors were achieved and the detections were highly sensitive. The advantages of rapid pretreatment, completely free of organic solvent, magnet assisted phase separation and recyclability of magnetic ionic liquid were simultaneously realized in an analytical method for the first time. Under the optimum conditions, Satisfactory recoveries, linear ranges, enrichment factors, precisions and limits of detection and quantification were obtained. The analysis of real milk was satisfactory. Although this method was just recently developed by us, it is showing great potential for highly sensitive detection of extremely trace amount of targeted analytes in foods and drinks.

Selective separation and simultaneous recoveries of amino acids by temperature-sensitive magnetic ionic liquid aqueous biphasic system

Two temperature-sensitive magnetic ionic liquids (MILs) based on polypropylene glycol 600 were used to construct novel temperature-sensitive magnetic ionic liquid aqueous biphasic systems (MILABSs) with different inorganic salts. Phase behaviors were studied in detail to give useful guidance for practical separation applications. These developed temperature-sensitive MILABSs were further employed for the selective separation of arginine and tyrosine mixtures as well as their simultaneous recoveries. Several factors affecting extraction efficiencies of both amino acids were optimized to achieve satisfactory selectivity. Magnet was applied to enhance phase separation efficiency. After extraction, for the MIL-rich phase, both pure arginine and MIL were perfectly recovered simply by heating. For the salt-rich phase, pure tyrosine was easily obtained simply by pH adjustion and cooling. This is the first time to realize simultaneous recoveries of targeted compounds from both MIL-rich phase and salt-rich phase for a temperature-sensitive MILABS. The whole separation and recovery processes were simple and free of any organic solvents. Moreover, temperature-sensitive MIL could be reused for at least 6 times with steadily satisfactory extraction performances. These specific temperature-sensitive MILABSs applied for selective separation and simultaneous recoveries of amino acids is revealing great potential for the simultaneous recoveries of different targeted compounds in an industrial separation-recovery process.

Dispersive solid-phase extraction of non-steroidal anti-inflammatory drugs in water and urine samples using a magnetic ionic liquid hypercrosslinked polymer composite

In this work, Friedel-Crafts alkylation was successfully applied to prepare a magnetic ionic liquid hypercrosslinked polymer composite (Fe3O4@IL-HCP), which was subsequently employed as magnetic solid-phase extraction (MSPE) adsorbent for the isolation and enrichment of trace non-steroidal anti-inflammatory drugs (NSAIDs). The developed composite was comprehensively characterized using various techniques, with the results indicating that it possessed high saturation magnetization (39.44 em g − 1), large specific surface area (175 m2g − 1), and high adsorption capacity for NSAIDs. The adsorption behavior and mechanisms were also investigated in detail. NSAIDs were adsorbed onto the Fe3O4@IL-HCP sorbent via a heterogeneous multilayer process consisting of hydrogen bonding and π-π and electrostatic interactions. Additionally, the composite's large surface area and multiple active sites enabled extraction equilibrium within 6 min. By coupling with high performance liquid chromatography (HPLC), the developed MSPE/HPLC method was applied for the determination of selected NSAIDs in water and urine samples. The developed method displayed wide linear ranges, low limits of detection (0.12–0.30 ng mL−1 and 0.15–1.5 ng mL−1 in water and urine samples, respectively), sufficient recoveries (92.8–109%), and good precision (relative standard deviations ≤ 4.6%). Thus, the findings of this work provide an appealing alternative for the extraction and determination of trace NSAIDs in environmental water and biological samples.

Ionic liquid-loaded triazine-based magnetic nanoparticles for promoting multicomponent reaction

A novel hybrid magnetic ionic-liquid as a heterogeneous catalyst was synthesized by hybridization of imidazolium based-ionic liquid onto the nitrogen rich magnetic nanocomposite. The resulting catalyst (n-Fe3O4@SiO2-TA-SO3H IL) has two advantages besides recyclability: (i) high capacity of functional-SO3H group with imidazolium-IL cation for promoting symmetric and asymmetric Hantzsch reaction and (ii) easy recovery. Caused by the polymeric and magnetic nature of the n-Fe3O4@SiO2-TA-SO3H IL, large quantities of acidic groups were bound to the n-Fe3O4@SiO2-TA surface, which reduced the catalyst mass applied to the catalytic reaction. Moreover, superior catalytic performance and outstanding recyclability of n-Fe3O4@SiO2-TA-SO3H IL in mild condition make this method a green pathway for manufacture of satisfactory chemicals.

A Gadolinium-Based Magnetic Ionic Liquid for Dispersive Liquid-Liquid Microextraction of Ivermectin from Environmental Water.

The recently introduced gadolinium-based magnetic ionic liquid (Gd-MIL) has been exploited as an extractant in dispersive liquid-liquid microextraction (DLLME) for preconcentration of ivermectin (IVR) from water samples followed by analysis using reversed-phase HPLC with UV detection at 245nm. The utilized Gd-MIL extractant is hydrophobic with markedly high magnetic susceptibility. These features result in an efficient extraction of the lipophilic analyte and facilitate the phase separation under the influence of a strong magnetic field, thus promoting the method sensitivity and increasing the potential for automation. To maximize the IVR enrichment by DLLME, the procedure was optimized for extractant mass, dispersive solvent type/volume, salt addition and diluent pH. At optimized conditions, an enrichment factor approaching 70 was obtained with 4.0-mL sample sizes. The method was validated in terms of accuracy, precision, specificity and limit of quantitation. The method was successfully applied to the determination of IVR in river water samples with a mean relative recovery of 97.3% at a spiked concentration of 400ng/mL. Compared with other reported methods, this approach used a simpler procedure with improved precision, lower amounts of safer solvents and a short analysis time.