Synthesis Of Ionic Liquids Research Articles

Synthesis and physical properties of new low-viscosity sulfonium ionic liquids

Several new sulfonium ionic liquids (ILs) with dicyanamide ([DCA]−) and bis(trifluoromethylsulfonyl)imide ([TFSI]−) counter anions have been synthesized. Their viscosity and ionic conductivity values were determined. The ILs with [DCA]− were previously prepared by the metathesis reaction involving silver dicyanamide (AgDCA). We report here a very convenient and much less expensive method using an ion-exchange resin. The structures of these ILs have been confirmed by 1H-NMR, 13C-NMR, and elemental analysis. Some of these sulfonium ILs displayed low viscosity ( 10 mS cm−1). A concluding remark on structure-property relationship has also been drawn involving alicyclic and cyclic sulfonium cations vs. [DCA]− and [TFSI]− anions.

Facile synthesis of DBU-based protic ionic liquid for efficient alcoholysis of waste poly(lactic acid) to lactate esters

Several DBU-based protic ionic liquids were facilely synthesized, they were successfully used as solvents and catalysts for alcoholysis of poly(lactic acid) (PLA) to yield lactate esters. The structure of ionic liquids and reaction parameters were optimized. Using [HDBU][AA] as the catalytic medium, which was composed by a 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) cation and an acetate anion, the PLA could be completely depolymerized with a 91% methyl lactate yield under the conditions of 100 °C, 5 mol% catalyst loading for 5 h. The effect of alcohol structures on the catalytic behaviors was studied, and good to excellent product yields were obtained. Moreover, the developed [HDBU][AA] showed excellent recyclability and structure stability. A possible reaction mechanism concerning the synergistic effect of the anion-cation ions was proposed. The DBU-based protic ionic liquids presented herein are low-cost and one-step synthesized, exhibiting great potential as green and efficient platform for direct and selective alcoholysis of PLA.

Synthesis of new ionic liquids based on dicationic imidazolium and their anti-corrosion performances

Ionic liquids with high environmental value and adsorption properties are a requirement for the new trend for corrosion inhibitors. Here, we synthesis three new ionic liquids based on dicationic imidazolium (IL1, IL2 and IL3) to produce green inhibitors for stainless steel corrosion in acidic environment. The anionic portion of all prepared ionic liquids is BF4−. New ionic liquids were recognized by means of element inspection, FT-IR, TGA and 1H NMR spectroscopy. All prepared ionic liquids work as good corrosion inhibitors. Where their efficiencies are 91.5%, 98.4% and 83.3% for IL1, IL2 and IL3, respectively at 100 ppm. The counter portion of ILs (BF4−) has a great role in the adsorption process.

Cost-saving and control investigation for isopentyl acetate ionic liquid catalyzed synthesis through conventional and dividing-wall reactive distillation

The reactive distillation process regarding ionic liquid-catalyzed transesterification for iso-pentyl acetate production is attracting increasing attention owing to outstanding properties of green homogeneous catalysts. This work investigates the economics and controllability of conventional reactive distillation (CRD) and dividing-wall reactive distillation (RDWC) configurations for this reaction. The optimizations of both configurations are carried out based on the minimum total annual cost (TAC) by the sequential iterative procedures. Their effective control structures are proposed and verified when either feed flow or feed composition disturbances are introduced. The results show that the RDWC process permits the reduction of up to 22.8% in the TAC compared to the CRD process. Furthermore, it is justified in view of the integral squared errors calculated that both control structures represent good dynamic performances in regard to resisting two kinds of feed disturbances.

Synthesis, Photophysical Properties, and Biological Importance of Pyrimidinium Ionic Liquids

AbstractThe synthesis of a family of organic salts and ionic liquids using pyrimidine as a heterocyclic core, an essential structural subunit of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) has been achieved. The pyrimidine‐containing ionic liquids coupled with tetrafluoroborate and bis(trifluoromethane)sulfonamide ( and ) as counter anions were synthesised via the nucleophilic addition of one of the N‐atoms of a pyrimidine to the arylalkyl and aryloxy alkyl halides followed by anion metathesis using highly stable and non‐hygroscopic sodium tetrafluoroborate (NaBF4) and bis(trifluoromethane)sulfonimide lithium salt (LiN(SO2CF3)2) in good to excellent yield. Further, the synthesised ionic liquids were utilised to explore their in vitro antibacterial activities along with evaluation of their photophysical, physical and thermal properties. The assessment of in vitro minimum inhibitory concentration (MIC) study against several pathogenic bacteria revealed that the 1‐(3‐phenylpropyl)pyrimidin‐1‐ium tetrafluoroborate (4 c: [(PhC3)Pym]BF4) is moderately active against Gram‐negative P. aruginosa bacteria (MIC=16 μg/mL) while 1‐phenethylpyrimidin‐1‐ium tetrafluoroborate (4b: [(PhC2)Pym]BF4), 1‐(3‐phenylpropyl)pyrimidin‐1‐ium tetrafluoroborate (4 c: [(PhC3)Pym]BF4), 1‐(phenoxypropyl)pyrimidin‐1‐ium tetrafluoroborate (4 d: [(PhOC3)Pym]BF4) and 1‐(phenoxybutyl)pyrimidin‐1‐ium tetrafluoroborate (4 e: [(PhOC4)Pym]BF4) exhibit moderate to good bioactivities against Gram‐positive S. aureus, and B. pumilis, respectively.

Imidazolium Chloride Immobilized Fly Ash as a Heterogenized Organocatalyst for Esterification Reaction under Microwave Irradiation Heating

An efficient solventless one-pot procedure for the synthesis of imidazolium-based ionic liquid under microwave irradiation is described in which 1-methylimidazole was modified by organosilane (3-chloropropyl triethoxysilane). This ionic liquid 1-methyl-3-[(triethoxysilyl)propyl]imidazolium chloride (TMICl) is immobilized on Mechanically activated Fly Ash (MFA) by co-condensation method to develop an active organocatalyst (TMICl/MFA). The mechanical activation has generated significant number of silanol groups suitable for immobilizing ionic liquids. For characterization of various materials, different techniques viz, XRD, FTIR, SEM-EDX, TGA, BET surface area, H1NMR are used. The prepared TMICl/MFA exhibited high catalytic activity for a series of microwave assisted esterification of aliphatic alcohols and salicylic acid for four successive reaction cycles under optimized conditions.

Synthesis, properties and adjuvant activity of docusate-based ionic liquids in pesticide formulations

Anionic surfactants are the largest group of surface-active compounds used in industry; therefore, the aim of this study was to adjust the properties of docusate salts by the introduction of appropriate counterions. Thus, low-toxicity cations were selected to obtain ionic liquids with the desired surface activity. The fundamental influence of the cation on the physicochemical properties was observed. Although the cations were characterized by low amphiphilicity, their selection has a significant impact on the surface parameters. Due to the surface properties of the obtained compounds, they were effective pesticide adjuvants with higher efficacy compared to the currently used additives.

Synthesis and Aggregation Behavior of Trisiloxane Ionic Liquids in Aqueous Solution

AbstractTrisiloxane ionic liquids with polyether groups (Si3pyCl‐EO3) were synthesized via thiol‐ene reaction between 1‐methyl‐1‐[bis(vinyldimethylsiloxy)methyl]silylpropylpyrrolidinium chloride (Vi‐Si3pyCl) and tri(ethylene glycol) methyl ether thiol. The aggregation behavior of the trisiloxane ionic liquids, Si3pyCl‐EO3 and Vi‐Si3pyCl, in aqueous solution was investigated using surface tension, electrical conductivity, dynamic light scattering, and transmission electron microscopy. The structures of trisiloxane ionic liquids can obviously influence their aggregation behavior. Vi‐Si3pyCl has excellent surface activity (22.3 mN m−1). However, Si3pyCl‐EO3 can only reduce the surface tension of water to 33.5 mN m−1. In comparison with Vi‐Si3PyCl, Si3PyCl‐EO3 has a bulkier hydrophobic group and a higher Αmin value (127.8 Å2) caused by the introduction of the tri(ethylene glycol) methyl ether groups by thiol‐ene reaction. The micellization of Vi‐Si3PyCl is entropy driven, while the aggregation process of Si3PyCl‐EO3 in aqueous solution is enthalpy driven.

Cellulose Dissolution and Biomass Pretreatment Using Quaternary Ammonium Ionic Liquids Prepared from H-, G-, and S-Type Lignin-Derived Benzaldehydes and Dimethyl Carbonate

The synthesis of novel benzyl alkylammonium ionic liquids (IL) from starting materials derived from grass, softwood, and hardwood lignin was performed using batch reactor systems followed by facile methyl carbonate ion exchange chemistry. Approximately 90% yields of the ILs were achieved over three synthetic steps, and all novel materials were fully characterized by 1H and 13C nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. The structure–activity relationships of the lignin-derived ILs were evaluated for their ability to dissolve microcrystalline cellulose and convert switchgrass to fermentable sugars (glucose and xylose). All ILs tested, including a 1:1:1 mixture of ILs prepared from vanillin, syringaldehyde, and p-anisaldehyde yielded 52–71% of the glucose and 50–71% of the xylose from the total amount of glucan and xylan available in the raw feedstock. These data compared well to the yields obtained from switchgrass pretreatment with the IL, 1-ethyl-3-methyl imidazolium a...

Synthesis, characterization, ecotoxicity and biodegradability evaluations of novel biocompatible surface active lauroyl sarcosinate ionic liquids

Ionic liquids (ILs) based surfactants have been emerged as attractive alternatives to the conventional surfactants owing to their tailor-made and eco-friendly properties. Therefore, present study described the synthesis of nine new fatty amino acids based IL surfactants utilizing lauroyl sarcosinate anion and pyrrolidinium, imidazolium, pyridinium, piperidinium, morpholinium and cholinium cations for the first time. The synthesized surface active lauroyl sarcosinate ionic liquids (SALSILs) were characterized by 1H NMR, 13C NMR and TGA. Next, the surface tension and critical micellar concentrations were determined and compared with the surface properties of ILs based surfactants. Further, the toxicity and biodegradability of the synthesized SALSIILs were evaluated to confirm their safe and efficient process applications. The studies revealed that three out of nine synthesized SALSILs containing pyridinium cation have showed strong activity towards the tested microbial growth. The remaining six SALSILs met the biocompatible measures demonstrating moderate to low activity depends on the tested microbes. The alicyclic SALSILs containing morpholinium and piperidinium cations have demonstrated 100% biodegradation after 28 days of the test period. Overall, it is believed that the synthesized SALSILs could effectively replace the conventional surfactants in a wide variety of applications.

Synthesis, molecular docking and ADMET study of ionic liquid as anticancer inhibitors of DNA and COX-2, TOPII enzymes

A new ionic liquid was synthesized by the reaction of caprolactam with salicylic acid (CL-SA) and characterized by analysis of spectroscopic and DSC data. The optimized geometry and the electrostatic potential map of CL-SA were calculated with DFT method using the wb97xd/6-31++G(d,p) level of theory. Molecular docking study of the CL-SA was carried out to clarify the probable binding modes between the title compound and DNA and COX-2 and TOPII enzymes. In silico ADMET study was also performed for predicting pharmacokinetic and toxicity profile of the synthesized ionic liquid which expressed good oral drug-like behavior and non-toxic nature. It was revealed that the compound has a potential to become a lead molecule in drug discovery process.Communicated by Ramaswamy H. Sarma

Synthesis and application of amino alcohol-derived chiral ionic liquids, as additives for enantioseparation in capillary electrophoresis

In this study, three functionalized chiral ionic liquids (CILs) derived from l-valinol, l-prolinol and l-phenylalaninol, namely N,N,N-trimethyl-l-valinol-bis(trifluoromethanesulfon)imide ([TMLV]+[Tf2N]−, CIL1), N,N-dimethyl-l-prolinol-bis(trifluoromethanesulfon)imide ([DMLP]+[Tf2N]−, CIL2) and N,N,N-trimethyl-l-phenylalaninol-bis(trifluoromethanesulfon)imide ([TMLP]+[Tf2N]−, CIL3), were synthesized and subsequently utilized for enantiomeric separation in capillary electrophoresis (CE) with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) as chiral selector for the first time. Compared with traditional single HP-β-CD separation system, the synergistic system exhibited substantially improved separations of six tested drugs. Using the CIL1/HP-β-CD as a model system, the influence of crucial parameters including the type and proportion of organic modifier, CILs concentration, HP-β-CD concentration and buffer pH was investigated in detail. Additionally, molecular modeling with AutoDock was applied to elucidate the enhanced enantioselectivity in the presence of CILs, which has certain guiding value in predicting the migration order of the enantiomers and studying the interactions important for the chiral recognition.

Ionic Liquids and Salts from Ibuprofen as Promising Innovative Formulations of an Old Drug.

Herein we report the synthesis of novel ionic liquids (ILs) and organic salts by combining ibuprofen as anion with ammonium, imidazolium, or pyridinium cations. The methodology consists of an acid-base reaction of neutral ibuprofen with cation hydroxides, which were previously prepared by anion exchange from the corresponding halide salts with Amberlyst A-26(OH). In comparison with the parent drug, these organic salts display higher solubility in water and biological fluids and a smaller degree of polymorphism, which in some cases was completely eliminated. With the exception of [C16 Pyr][Ibu] and [N1,1,2,2OH1 ][Ibu], the prepared salts did not affect the viability of normal human dermal fibroblasts or ovarian carcinoma (A2780) cells. Therefore, these ibuprofen-based ionic liquids may be very promising lead candidates for the development of effective formulations of this drug.

Synthesis and evaluation of a protic ionic liquid as a multifunctional lubricant additive

An oil soluble multifunctional protic ionic liquid (IL) was synthesized and its tribological and antioxidant properties in poly alpha olefin (PAO4) were investigated. The tribological results demonstrated that the IL significantly reduced friction and wear of PAO4. The PAO4 blend with IL resulted in an induced oxidation time of 555 min which is 8.2 and 3.5 times higher than that of pure PAO4 and PAO4 with zinc dialkyl dithiophosphate (ZDDP) for the rotating pressure vessel oxidation test. It is likely that free nonylated diphenylamine acted as a radical scavenger to enhance antioxidant performance, while free bis(2-ethylhexyl) phosphate was more prone to adsorb and react with the metal surface to form a phosphorus-rich tribofilm in order to protect the rubbing surface.

Synthesis and characterization of novel chiral imidazolium and pyridinium ionic liquids derived from tartaric acid and 2-oxazolidinone

Novel chiral imidazolium and pyridinium ionic liquids based on tartaric acid and 2-oxazolidinone were designed. Symmetrical dicationic ionic liquids based on tartaric acid have been synthesized and characterized. These chiral ionic liquids were designed by employing very short and simple methods. Incorporation of alkyl halide over tartaric acid and 2-oxazolidinone is an important step. N-methyl imidazole and pyridine were used for preparation of quaternary salts. These ionic liquids have been evaluated for the asymmetric sulfide oxidation. Chiral ionic liquids based on tartaric acid showed superior chiral inducing property as compare to 2-oxazolidinone based chiral ionic liquids.

Novel Synthesis of Choline-Based Amino Acid Ionic Liquids and Their Applications for Separating Asphalt from Carbonate Rocks

In this study, a series of choline-based amino acid ionic liquids have been synthesized in an economic method and are used to assist solvents with extracting asphalt from carbonate rocks. All of the ionic liquids perform well in extracting asphalt, especially choline histidine, by which the single-step recovery of asphalt is up to 91%. Furthermore, oil product with higher quality (fewer solids entrained) is also obtained. Molecular dynamics simulation and thermodynamic equilibrium method are applied to investigate the role of amino acid ionic liquids via interaction energy calculation and surface free energy calculations. The simulation results suggest that the ionic liquid phase is beneficial for the transfer of oil fraction from the carbonate surface to the organic solvent phase. Moreover, the results of simulated calculation show that the introduction of a functional group with conjugated structures into ionic liquid, such as an imidazole ring and a benzene ring, is beneficial for enhancing oil recovery, which are in accordance with the results of experimental tests.

Synthesis, microstructure and volumetry of novel metal thiocyanate ionic liquids with [BMIM] cation

We present a new family of ionic liquids (ILs) with a common cation, 1-butyl-3-methyl imidazolium, the popular [BMIM]+ (also written C4C1Im+) and a variety of anionic complexes (also called adducts) based in thiocyanate (SCN)−: one blank compound, BMIM(SCN), and ten doped with metals having different oxidation states: Al+3, Mn+2, Fe+3, Cr+3, Ni+2, Hg+2, Zn+2, Co+2, Cd+2 and Cu+, forming, respectively, [BMIM]3[Al(SCN)6], [BMIM]4 Mn(SCN)6, [BMIM]3 Fe(SCN)6, [BMIM]3 Cr(SCN)6, [BMIM]4 Ni(SCN)6, [BMIM]2 Hg(SCN)4, [BMIM]2 Zn(SCN)4, [BMIM]2 Co(SCN)4, [BMIM]2 Cd(SCN)4 and [BMIM]3 Cu(SCN)4. All of them were synthesized by us, except the blank IL and the Co thiocyanate, which are commercial. Obtained products have been characterized by NMR, and also by electrospray ionization, MS-ES, which allows the determination of the new ILs purities. Then, compounds have been analyzed using FT-IR and Raman spectroscopy. In addition, magnetic susceptibility and refractive index measurements were performed in some of the compounds studied, as well as thermal characterization using DSC and TGA. Finally, experimental measurements of density on all those ILs have been performed, and for some of the samples in a broad temperature range (about 100 K). In spite of being very similar compounds from the chemical point of view, they present quite different physical properties, including optical, thermal and magnetic ones… Also, they show different oxidation states (one with +1, six with +2 and other three with +3). We guess that this family of ILs will have interesting applications, mainly for photonic devices.

Synthesis and characterization of chiral ionic liquids based on quinine, l-proline and l-valine for enantiomeric recognition

The separation of enantiomers remains a major challenge for the pharmaceutical industry. In this work, eight chiral ionic liquids (CILs) directly derived from the ‘chiral pool’ were synthesized and characterized in order to develop enantioselective systems, for the chiral resolution. According to their chiral cations, three different groups of CILs were prepared, namely based on quinine, l-proline and l-valine, and their enantiomeric recognition ability evaluated. For that purpose the diastereomeric interactions between a racemic mixture of Mosher's acid sodium salt and each CIL were studied using 19F NMR spectroscopy. The remarkable chemical shift dispersion induced by some CILs demonstrates their potential application in chiral resolution. Additionally the optical rotation, thermophysical properties and ecotoxicity against the marine bacteria Aliivibrio fischeri of these chiral ionic liquids were addressed.

Protein-Rich Biomass Waste as a Resource for Future Biorefineries: State of the Art, Challenges, and Opportunities.

Protein-rich biomass provides a valuable feedstock for the chemical industry. This Review describes every process step in the value chain from protein waste to chemicals. The first part deals with the physicochemical extraction of proteins from biomass, hydrolytic degradation to peptides and amino acids, and separation of amino acid mixtures. The second part provides an overview of physical and (bio)chemical technologies for the production of polymers, commodity chemicals, pharmaceuticals, and other fine chemicals. This can be achieved by incorporation of oligopeptides into polymers, or by modification and defunctionalization of amino acids, for example, their reduction to amino alcohols, decarboxylation to amines, (cyclic) amides and nitriles, deamination to (di)carboxylic acids, and synthesis of fine chemicals and ionic liquids. Bio- and chemocatalytic approaches are compared in terms of scope, efficiency, and sustainability.

Monitoring an ionic liquid synthesis with in-situ IR-spectroscopy – The intricacy of solvent effects

This work focuses on the ionic liquid (IL) synthesis starting from dimethyl carbonate and 1-ethylimidazole in methanol. In-situ IR-spectroscopy is used to gain time-dependent concentrations for kinetic analysis. The reaction is found to be self-accelerating, since the solvent polarity increases with the formation of the ionic product. This corresponds to a salting-out effect. Since the reaction rate is increasing in the beginning, pre-dosing of the product is proposed to enhance the overall productivity. Therefore, the space-time-yield is calculated as the arithmetic mean of the reaction rate with a varying starting point. It turns out that pre-dosing does not enhance the productivity here, since the space-time-yield of the complete reaction progress is below the initial reaction rate. Beyond that, two sharp bends can be observed in the progress of the reaction rate coefficient that point towards sudden changes in the reaction environment. The first bend can be assigned to a phase separation of the ionic liquid on a microscopical scale. The second bend takes place when the IL concentration surpasses roughly one sixth of the methanol concentration. Above that threshold, the whole amount of methanol is captured in the solvation shell of the anion monomethyl carbonate, as quantum chemical calculations suggest. Finally, the reaction rate coefficients were calculated using quantum chemical methods with respect to the solvent environment. The theoretical results show a good accordance with experimental values for the starting compositions. Thus, theoretical calculations help to estimate productive reaction mixtures.