Synthesis Of Ionic Liquids Research Articles

Determination of purity and anionic exchange efficiency of amino acid ionic liquids synthesis by multiple-injection capillary zone electrophoresis

The purity of ionic liquids (IL) is important for its performance, so the methods able to quantify low concentration impurities are necessaries. Therefore, this paper aims to determine the purity and the anionic exchange efficiency for the preparation of amino acids ionic liquids (AAIL). For this, a Multiple-Injection Capillary Zone Electrophoresis (MICZE) method with direct UV detection was developed and optimized for iodide (I−) determination as impurity of AAIL synthesis, comparing this method with traditional injection modes. Furthermore, this paper aims to demonstrate the use of factorial design methods for the optimization of MICZE method. The method optimization allowed five consecutives I− injections of sample in a single run, with analysis time of less than 3 min, showing a larger analytical frequency, counting with 31 injections per hour. It was possible to determine the high purity of the prepared and analyzed AAIL, ranging from 89% to 95% and its overall ionic exchange yield varying from 55% to 87%.

Synthesis, structure-properties relationship and biodegradability assessment of novel protic ionic liquids

In the present study, the design, synthesis and biodegradability assessment of 14 protic ionic liquids (PILs), among which nine are presented for the first time in bibliography, is presented. Furthermore, since PILs are considered as alternative green solvents with favorable properties for a variety of applications, we herein report the study of two of the most important PILs physicochemical properties, thermal behavior (melting, cold crystallization and glass transition temperatures) and viscosity. The effect of selected structural features of the PILs ions (such as the aromatic and alicyclic ring, the ions size and the presence of hydroxyl groups) on the above-mentioned properties has been also discussed.

Synthesis and Physical Properties of Tunable Aryl Alkyl Ionic Liquids (TAAILs).

Tunable aryl alkyl ionic liquids (TAAILs) based on the imidazolium cation were first reported in 2009. Since then, a series of TAAILs with different properties due to the electron‐donating or ‐withdrawing effect of the substituents at the aryl ring has been developed. Herein, a wide variety of those ionic liquids (ILs) is presented in terms of their cation structure. The authors synthesized ILs containing the bromide or bis(trifluoromethane)sulfonimide anion and 1‐aryl‐3‐alkyl imidazolium cations with various substituents in the ortho and/ or para position of the phenyl ring and alkyl chains of different lengths varying from butyl to dodecyl. The differences of their physical properties (melting point, thermal decomposition, viscosity, electro‐chemical window) of these ILs are reported according to their structure.

Comparative Studies between Conventional Techniques and Green Chemistry to Synthesis of Novel Piperidinium Salts Ionic Liquids (PBSILs)

Comparative Studies between Conventional Techniques and Green Chemistry to Synthesis of Novel Piperidinium Salts Ionic Liquids (PBSILs)

Synthesis, characterization and biological activity of bifunctional ionic liquids based on dodine ion.

Development of new plant protection strategies has become an urgent matter in modern agriculture, in view of the evidently proved negative effect of currently used active ingredients of pesticides. In recent years, much effort has been made to eliminate the use of pesticides established to be toxic to pollinators. In this study, we present a group of new bifunctional ionic liquids based on dodine (N-dodecylguanidine) cation whose physical and biological properties have been modified relative to those of the commercially available N-dodecylguanidine acetate. The decreased level of residue of active substances in plant tissues reduces their availability to pollinators, which increases the safety of their use. Moreover, lower environmental impact in combination with high antifungal activity and an additional biological function, that is the systemic acquired resistance induction, are in line with the goals of sustainable agriculture. The presented approach shows the possibility of derivatization of commonly used fungicide into the form of bifunctional salts whose physical and biological properties can be easily modified. The paper reports successful design and synthesis of new sustainable and green chemicals for the modern agriculture, being less toxic to the environment and human health but still effective against pathogens. © 2021 Society of Chemical Industry.

Synthesis and properties of Polymeric ionic liquids (PILs) bearing hydrophilic PEO groups: Evaluation of gas and water vapor separation performance

New pyridinium based PILs containing PEO pendants were synthesized to be examined as CO2 and water selective membranes. A two-step synthetic procedure was followed including an N-methylation reaction of a precursor copolymer and a subsequent anion exchange metathesis to afford the corresponding PILs. The prepared PILs having different counter-anions form mechanically robust, flexible membranes, which exhibit high thermal stability and Tgs close to room temperature. It was examined the effect of anion nature on physicochemical as well as gas/water vapor separation properties. The conversion of the precursor copolymer to its corresponding PIL analogues led to Tg increase and thermal stability decrease of the latter. Surprisingly, the gas permeability for all PILs was decreased compared to precursor owing to the strong cation-anion interactions developed in the PIL structures which lead to a tighter polymer chain packing and consequently to gas diffusion hindering. The PIL containing the C(CN)3− anion (PIL750-C(CN)3) experiences the lowest CO2 permeability compared to TFSI− and MeSO4− which is accompanied by a very high CO2/CH4 selectivity value of 70 that is among the highest reported in the literature for PILs. This behavior can be attributed to its dense polymer chain packing and thus to its strong sieve-sieving ability associated with the diffusion-driven permeability decrease. Regarding water vapor permeability, it was evidenced that the PIL containing the MeSO4− anion (PIL750-MeSO4) showed the highest water vapor permeability (80,000 Barrer) compared to anions TFSI− and C(CN)3−, which is attributed to MeSO4− increased hydrophilicity and higher hydrogen bond basicity. The high water permeability is accompanied by a very high H2O/CO2 and H2O/N2 selectivity. The water vapor effect on gas permeation of PIL750-TFSI and PIL750-MeSO4 under process gas streams conditions using two different mixtures with compositions 3% H2O:14.5% CO2:82.5 %N2 and 3% H2O:48.5% CO2:48.5% CH4, respectively, was also investigated. The results demonstrate that gas permeability of all tested gases increased under humid conditions due to plasticization induced by water vapor. Accordingly, the separation factors decreased when compared with ideal selectivities in dry conditions for both PILs. However, PIL750-MeSO4 combines the high water vapor permeability with the high H2O/CO2 and HO2/N2 separator factors highlighting its potential to be used in flue gas dehydration and air dehydration.

Facile Synthesis of Novel Polyethyleneimine Functionalized Polymeric Protic Ionic Liquids (PolyE‐ILs) with Protagonist Properties for Acid Catalysis

AbstractPolyethyleneimine (PEI), a potent architecture backbone was explored for the synthesis of novel polymeric ionic liquids (PolyE‐ILs) with protagonist properties. The simple quaternization of PEI dendrimer with Bronsted acids (H2SO4, H3PO4, CH3SO3H, CF3COOH and TsOH) leads to formation of series of protic PolyE‐ILs with corresponding counter anions [HSO4]−, [H2PO4]−, [CH3SO3]−, [CF3COO]− and [TsO]−. The physicochemical properties of synthesized PolyE‐ILs were studied by using TGA, Hammett acidity, hydrodynamic radii, solubility, and elemental analysis. PolyE‐ILs showed characteristic Hammett acidity (0.94–1.78), good thermal stability (<250 °C) and enhanced hydrodynamic radii. However, use of PolyE‐IL can be promoted for their wide applications as an acid catalysts. The reported PolyE‐IL‐1 with sulfonic acid counter ion was explored as catalyst for esterification of (E)‐cinnamic acids and it showed good catalytic activity. The enhanced hydrodynamic radii due to the branched architecture of PEI dendrimers facilities the separation process via Nanofiltration (NF) membrane with no membrane fouling. Thus, PolyE‐ILs can be highly active, easily recoverable, and reusable catalyst for esterification reactions with superior sustainability and economics. In addition to this the present one pot PolyE‐IL synthesis process is non‐complex and simple as compared to conventional post polymerization, ion exchange, and nucleophilic addition etc., strategies for synthesis of PILs.

An efficient Brønsted acid ionic liquid catalyzed synthesis of novel spiro1,2,4-triazolidine-5-thiones and their photoluminescence study

We have synthesized a novel Bronsted acidic ionic liquid, 1-(2-hydroxyethyl)-1-(4-sulfobutyl)piperidin-1-ium hydrogen sulfate, [HEPiPYBSA]+HSO4− and explored its catalytic efficiency for synthesis of indenoquinoxalone tethered spiro-1,2,4-triazolidine-5-thiones from reaction of 11H-[1,2-b]quinoxalin-11-one and thiosemicarbazide. The most stable geometries of synthesized ionic liquid (IL) [HEPiPYBSA]+ HSO4− were obtained through systematically optimization by the DFT theory at B3LYP/6-31G* level. A photoluminescence study of the synthesized spiro-1,2,4-triazolidine-5-thiones revealed a remarkable fluorescent activity. The advantages of the present method are a reusable hydrophilic green catalyst, mild reaction conditions, use of benign solvent system, short reaction span, high atom economy and wide substrate scope.

Synthesis of Ammonium-Based Ionic Liquids for the Extraction Process of a Natural Pigment (Betanin)

The use of new synthesized ammonium-based ionic liquids was explored as an alternative to the current process implemented in the betanin extraction from red beet juice, resulting in high yields: 70% and 82%. Betanin is a vegetal pigment that has been applied to a large variety of products in the food industry, which is important, for it can work as a substitute for the red synthetic dyes used nowadays. Additionally, the use of the kosmotropic salt sodium acetate was explored in order to separate the complex formed by the ionic liquid and pigment of interest in a process that combined two techniques: ATPS (aqueous two-phase system) and SOES (salting-out extraction system). The results reveal that the studied techniques could work as a novel process for the extraction of betanin from red beet juice employing ionic liquids, which have not been tested for this purpose in other research.

Synthesis, Crystal Structure, and Thermal Properties of Metal-Containing Ionic Liquids with Spiro Cations: (Spiro)2MCl4 (Spiro = 2,8-Dioxo-5-azoniaspiro[4.5]decane or 2-Oxo-5-azoniaspiro[4.4]nonane, M = Mn, Ni, Co)

Synthesis, Crystal Structure, and Thermal Properties of Metal-Containing Ionic Liquids with Spiro Cations: (Spiro)2MCl4 (Spiro = 2,8-Dioxo-5-azoniaspiro[4.5]decane or 2-Oxo-5-azoniaspiro[4.4]nonane, M = Mn, Ni, Co)

A novel phosphonium ionic liquid electrolyte enabling high-voltage and high-energy positive electrode materials in lithium-metal batteries

The synthesis of a new ionic liquid (IL), consisting of the symmetric tetra-butyl-phosphonium (P4444+) cation and the (nonafluorobutanesulfonyl)(trifluoromethanesulfonyl)imide (IM14–) anion, via a facile and environmentally-friendly aqueous route is reported. The novel P4444IM14 IL demonstrates excellent thermal and electrochemical stability (beyond 6 V vs. Li+/Li0 (against Ni-foil)) in combination with good near-room temperature conductivity and ionic liquid characteristics, such as non-measurable volatility and exceptional flame-retardant properties. Employed as electrolyte component in Li-metal cells together with the high-voltage, Li1.2Ni0.2Mn0.6O2 positive electrode material, enables an initial discharge capacity of 264 mA h g-1 at 12.5 mA g−1 and improved initial Coulombic efficiency. Additionally, the discharge capacity retention is promising (92.3% after 50 cycles and 84.4% after 100 cycles) when compared with using a conventional organic carbonate-based electrolyte (55.5% after 50 cycles). Further development of this ionic liquid electrolyte may facilitate the practical application of Li-metal anodes in high-voltage/high-energy lithium batteries.

Separation of lithium isotopes by crown ether-room temperature ionic liquid-anisole friendly solvent system

The solvent extraction separation of lithium isotopes has become of growing interest due to the need for 6Li and 7Li isotopes in the nuclear industry. A one-step synthesis of room temperature ionic liquid with low viscosity 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIm][NTf2]) (with reaction yields of 87.47%) was used by the ultrasonic method. The addition of ionic liquid [EMIm][NTf2] in the system significantly improved the extraction efficiency and separation factor compared to the traditional organic solvent anisole for extraction separation of lithium isotopes. The distribution ratio increased from 0.00145 (with the single stage separation factor of 1.024 ± 0.001) to 0.134 (with the single stage separation factor of 1.034 ± 0.001). Furthermore, a multi-stage extraction process was intended to enhance lithium isotope separation performance. Each stage of stripping can be considered as an extraction separation equilibrium process, in which the strip liquor from the load organic phase is used for separation in the next stage as the “original aqueous solution”. The abundance of 6Li+ gradually improved with an increase in the extraction stages. The relative abundance of 6Li+ increased by 1.492% at the 20-stage extraction separation (from 7.53% to 9.022%). This new and simple approach (stripping cross-flow multistage method (SCFM)) was to achieve large enrichment of lighter isotopes of lithium (6Li+) by combined extraction and stripping process. In summary, the present study offers the possibility for the enrichment of 6Li+ during lithium isotope extraction separation.

Reactive Amphiphilic Aprotic Ionic Liquids Based on Functionalized Oligomeric Silsesquioxanes

Abstract This paper discusses a method for the synthesis of ionic liquids which are mixtures of oligomeric silsesquioxanes (OSS) of polyhedral structure and their analogs with open chains containing aprotic cationic ionic groups with different lengths of alkyl substituents and reactive hydroxyl groups in the organic shell (OSS-ILs). This method includes the quaternization reaction of OSS with tertiary amine and primary and secondary hydroxyl groups by n-bromopropane or n-bromodecane. Obtained compounds were amorphous with glass transition temperature below 0 °C. The ionic conductivity of OSS-ILs increases with decreasing the alkyl substituent length and reaches 1.4·10−3 S/cm at 120 °C. Dynamic light scattering reveals that the length of alkyl substituent of OSS-ILs affects the assembly behavior in aqueous solutions. According to atomic force microscopy images, the surface morphology of the film of OSS-IL with short substituents showed disk-like flat micelles with an average diameter of 229 ± 92 nm and height of 2 nm. OSS-IL with long substituents formed polydisperse micellar morphologies, of which a majority showed elongated, worm-like structures with an average height of 2 nm. The ability to endow ionic conductivity and to tune morphology makes these materials promising as potential polymer electrolytes for various electrochemical applications, in particular ionic sensors and energy storage devices.

Synthesis and Characterization of New Imidazolium Ionic Liquid Based Energetic Plasticizers

AbstractIn the present research, two new ionic liquids (ILs) with imidazolium cation and dicyanamide anion were synthesized for their plasticizing capacity in solid propellants. The structure of plasticizers was confirmed by FT‐IR, 13C‐NMR and 1H‐NMR spectrum and their thermal behaviors were studied by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results of the thermal analysis showed that the thermal stabilities of these ILs are suitable and the phase change curves of ILs were consistent with their weight reduction changes by increasing temperature. Moreover, the low viscosities and high densities obtained from the ILs show that these compounds could be convenient alternatives for polymeric plasticizers in propellant compositions. To understand the plasticizing effect of synthesized IL plasticizers on glycidyl azide polymer (GAP), blends of 20 % of the synthesized IL plasticizers were prepared and analysed to determine glass transition temperature and viscosity. Among all plasticizers, [Vin‐IL] [N(CN)2]‐GAP and [Me‐IL][N(CN)2]‐GAP blends produced the lowest Tg. The results of viscosity analysis show that all synthesized IL plasticizers have reduced the viscosity of the GAP binder, which indicates the plasticizing properties of ILs.

Synthesis, characterization, antimicrobial activity and computational exploration of ortho toludinium carboxylate ionic liquids

As Ionic Liquids (IL) was considered as designer molecules for use in chemical and biological sectors, its demands and researches have been increasing day by day. To design new ILs and evaluate its antimicrobial activities, the ortho-toludinium carboxylate ionic liquids (OTILs) were synthesized through the Brønsted acid-base neutralization reaction between ortho toluidine and carboxylic acids with yields (74 to 88)%. The synthesized OTILs were characterized by FT-IR, UV and 1H-NMR, which had confirmed their conversion of the reaction and their structure. The eight human pathogenic bacteria were used for antibacterial screening, as well as three antifungal activities had estimated against three fungi. However, the synthesized ILs showed the good result to antimicrobial activity against both bacteria and fungi. Due to show high antimicrobial activity, MIC was performed against two bacteria whereas the MIC had found the range 250 to 500 mM. Furthermore, density functional theory (DFT) had used for determining the HOMO, LUMO and chemical reactivity descriptors for the computational investigation of OTILs, as well as molecular docking screening had performed against three pathogens. By the molecular docking score as binding affinity and chemical descriptors, the effect of alkyl chain and electronegative atom in anion had direct contribution on antimicrobial activity which was the similar result from the experimental data of antimicrobial activity. Finally, attaching Fluorine atom in anion could show the highest antimicrobial activity and docking score among chlorine, bromine, iodine even alkyl chain.

TBDH][HFIP] ionic liquid catalyzed synthesis of quinazoline-2,4(1H,3H)-diones in the presence of ambient temperature and pressure

The utilization of carbon dioxide under mild reaction conditions is an important aspect of the sustainable chemistry point of view. Herein, we prepared three bifunctional protic ionic liquids having 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) as a cation and an alcohol anions were prepared by simple neutralization of the super base TBD with proton donor alcohols such as hexafluoroisopropanol (HFIP), TFE (2,2,2-Trifluoroethanol) and TFA (2,2,2-Trifluoroacetic acid). These PILs were used as catalysts for chemical fixation of carbon dioxide into quinazoline-2,4(1H,3H)-diones. [TBDH+][HFIP-] protic ionic liquid (PIL) shows very good result compare to other PILs. As a bifunctional ionic liquid, it simultaneously activates 2-aminobenzonitrile as well as CO2 and shows excellent performance for the conversion of 2-aminobenzonitrile to quinazoline-2,4(1H,3H)-diones in presence of CO2 balloon pressure at 35 °C temperature. Moreover, the [TBDH+][HFIP-] PIL can be recycled up to six recycle run.

Lignin to Value-added Chemical Synthesis

Background: There is an increasing demand for innovation in petroleum system replacements. Towards this aim, lignocellulosic biomass is suggested as a possible sustainable source for the manufacturing of fuels and chemical production. This paper aims to investigate different kinds of β-O-4 lignin model compounds for the production of value-added chemicals in the presence of ionic liquids. Especially, cheap β-O-4 lignin model guaiacol glycerol ether (GGE) (Guaifenesin) is introduced to produce valuable chemicals and novel products. Methods: The research related to chemical depolymerization of lignocellulosic biomass activity is reviewed and an account of different methods such as thermal and microwave for the last 10 years is presented. So, this work provides an excellent background for academic research and it gives an efficient strategy for the manufacturing of novel value-added chemicals at an industrial scale. Results: The review concludes that ionic liquid microwave-assisted synthesis is a power-saving, cost-efficient, fast reaction, and clean way with high selectively and purity for the production of high-value chemicals rather than conventional heating. Guaiacol and catechol are some of these valuable chemicals produced from β-O-4 lignin model compounds with high demands and large industrial scale prospects. Conclusion: The β-O-4 lignin model compounds such as guaiacol glycerol ether (GGE) (Guaifenesin) are a good platform for developing food materials, perfumery, biorefinery, and pharmaceutical industry by ionic liquids-assisted lignin depolymerization method.

Ionic Liquids Based on the Concept of Melting Point Lowering Due to Ethoxylation.

Most of the commonly used Ionic Liquids (ILs) contain bulky organic cations with suitable anions. With our COMPLET (Concept of Melting Point Lowering due to Ethoxylation), we follow a different approach. We use simple, low-toxic, cheap, and commercially available anions of the type Cx(EO)yCH2COO– to liquefy presumably any simple metal ion, independently of its charge. In the simplest case, the cation can be sodium or lithium, but synthesis of Ionic Liquids is also possible with cations of higher valences such as transition or rare earth metals. Anions with longer alkyl chains are surface active and form surface active ionic liquids (SAILs), which combine properties of ionic and nonionic surfactants at room temperature. They show significant structuring even in their pure state, i.e., in the absence of water or any other added solvent. This approach offers new application domains that go far beyond the common real or hypothetical use of classical Ionic Liquids. Possible applications include the separation of rare earth metals, the use as interesting media for metal catalysis, or the synthesis of completely new materials (for example, in analogy to metal organic frameworks).

The effect of alkyl chain and electronegative atoms in anion on biological activity of anilinium carboxylate bioactive ionic liquids and computational approaches by DFT functional and molecular docking

The Brønsted acid-base neutralization was executed for synthesis of the anilinium carboxylate ionic liquids (ACILs), and obtained highly viscous liquids with yields about (90–94)%. These ILs were purified by distillation process and used vacuum oven, as well as characterized by FT-IR, UV spectroscopy and 1H-NMR. To evaluate the antimicrobial activity, the well diffusion method was used against eight human pathogenic bacteria, showing inhibition of zone at 13 mm–27 mm, and three fungi with result about 60%. Plus, the DFT functional from material studio 8.0 was used for evaluation of computational screening for estimating the chemical reactivity, HOMO, LUMO and HOMO-LUMO gap, recorded from -7.252 to -8.20 kcal/mol. The IL05 has showed about -6.5 kcal/mol docking score as standard inhibitor, as and higher than starting. Form AMDET properties, it has revealed that they have low toxicity, higher absorption through the biological system and non-carcinogenic. Finally, the electronegative groups, such as F, Cl and Br atoms in anion can show the higher antimicrobial activity and molecular docking score among all others while F atom containing IL05 shows the highest docking score and antimicrobial activity. However, it is concluded that rather than long large alkyl chain of anion, F atom (the highest electronegative atom) containing anion is better for biologically significance ILs.

Development of proton-exchange membrane fuel cell with ionic liquid technology

Fuel cells (FCs) are a chemical fuel device which can directly convert chemical energy into electrical energy, also known as electrochemical generator. Proton exchange membrane fuel cells (PEMFCs) are one of the most appealing FC systems that have been broadly developed in recent years. Due to the poor conductivity of electrolyte membrane used in traditional PEMFC, its operation at higher temperature is greatly limited. The incorporation of ionic liquids (ILs) which is widely regarded as a greener alternative compared to traditional solvents in the proton exchange membrane electrolyte shows great potential in high temperature PEMFCs (HT-PEMFCs). This review provides insights in the latest progress of utilizing ILs as an electrochemical electrolyte in PEMFCs. Besides, electrolyte membranes that are constructed by ILs combined with polybenzimidazole (PBI) have many benefits such as better thermal stability, improved mechanical properties, and higher proton conductivity. The current review aims to investigate the newest development and existing issues of ILs research in electrolyte and material selection, system fabrication method, synthesis of ILs, and experimental techniques. The evaluation of life cycle analysis, commercialization, and greenness of ILs are also discussed. Hence, this review provides insights to material scientists and develops interest of wider community, promoting the use of ILs to meet energy challenges.