Search

Microwave is a good candidate towards lipid extraction from microalgae in a bid to reduce the overall energetic consumption and extraction time. 1-octyl-3-methylimidazolium-based ILs belonging to 1st generation and 2nd generations, have been used. At 2.5% of [Omim][OAc] in the medium, 19.2% of lipid were obtained, while the conventional IL-less system only yielded 10.9%. More interestingly, the extraction efficiency increases with increasing amount of IL. A broader range of fatty acid profiles was also found to be extracted in the presence of ILs. The lipid extraction ability of the ILs was further confirmed and even dramatically enhanced under high pressure microwave irradiation. At 1.5% IL, the lipid yield reached 37% with FAME profile mirroring the results obtained by hydrophobic IL based extraction. The energy balance calculation have shown a reduction in the energy loss with the different type of IL used resulting in a 12% net energy gain with the [Omim][NTf2] IL based extraction. A key finding in this study suggests that both the polarity of the ILs and the electronegativity of the anions play an important role in the type of lipids extracted.

Four different dicyanamide-based ionic liquids (ILs), [Cnmpy][DCA] (n = 4, 6, 8, and 10), were synthesized, characterized, and used to separate ethylbenzene from n-octane. Equilibrium data for the corresponding ternary systems were measured at 313.15 K under atmospheric pressure. A higher selectivity is observed for lower aromatic concentrations in the feed (20% max); this is a key factor in selecting a suitable IL. The distribution ratio and selectivity obtained in this work are comparable to those of commercial solvents. The nonrandom two-liquid model (NRTL) was successfully used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. Moreover, the antimicrobial activities of the ILs were evaluated by examining their 50% effective concentrations (EC50) using the standard microbroth dilution test against four human bacterial pathogens. 1-Butyl 3-methylpyridinium dicyanamide [C4mpy][DCA] was found as the most suitable IL among those investigated because of i...

This present study is dedicated to the synthesis, characterization and microbial toxicity assessment of phosphonium- and ammonium-based ionic liquids (ILs) bearing four different anions phenylalalinate (Phe), taurinate (Tau), hydroxide (OH), and acetate (Ac). The structures of the subsequent ILs were confirmed by 1H and 13C nuclear magnetic resonance (NMR). Physicochemical properties such as density, thermal stability, conductivity, surface tension, and refractive index were measured. Subsequently, the in vitro toxicity profiles of the ILs were determined for selected Gram-positive and Gram-negative bacteria in terms of inhibition zones (IZ), minimum inhibitory concentrations (MIC), and minimum bactericidal concentrations (MBC). The results showed that the ILs were in the range of “practically harmless” to “harmless”. The order of the same was OH > Ac > Tau > Phe, with phenylalalinate being the most toxic anion owing to its aromatic nature. With reference to the experimental results, the nature of the critical micellar concentrations and water octanol partitioning was discussed in the context of microbial toxicity. Hence, it was shown that anions, rather than cations, were the major contributors to toxicity.

Biodiesel production via esterification/transesterification reactions can be catalyzed by homogenous or heterogeneous catalysts. Development of heterogeneous catalysts for biodiesel production is highly advantageous due to the ease of product purification and of catalyst recyclability. In this current work, a novel acidic [DABCODBS][CF3SO3]2 dicationic ionic liquid (DIL) was used as heterogeneous catalyst to produce biodiesel using oleic acid as model oil. The esterification was conducted under ultrasonic irradiation (20 kHz) using a 14 mm ultrasonic horn transducer operated at various duty cycles. It was observed that the duty cycle, amplitude, methanol to oil molar ratio, catalyst amount and reaction temperature were the major factors that greatly impact the necessary reaction time to lead to a high yield of biodiesel. The reaction conditions were optimized with the aid of Response Surface Methodology (RSM) designed according to the Quadratic model of the Box Behnken method. The optimum conditions were found to be at catalyst amount of 0.64 mol%, methanol to oil ratio of 14.3:1, temperature of 59 °C, reaction time of 83 min and amplitude of 60% in continuous mode. The results showed that the oleic acid was successfully converted into esters with conversion value of 93.20% together with significant reduction of reaction time from 7 h (using mechanical stirring) to 83 min (using ultrasonication). The results also showed that the acidic DIL catalyst we designed purposely was efficient to catalyze the ultrasonic-assisted esterification yielding high conversion of oleic acid to methyl oleate on short times. The DIL was also recycled and reused for at least five times without significant reduction in performance. Overall, the procedure offers advantages including short reaction time, good yield, operational simplicity and environmentally benign characteristics.

In this work the synthesis of five new Bronsted acidic ionic liquids (BAILs) bearing same anion (camphorsulfonate) but different cations; 3-(3-sulfopropyl)-imidazolium, 1-methyl-3-(3-sulfopropyl)-imidazolium, 1-methyl-3-(4-sulfobutyl)-imidazolium, 1-ethyl-3-(3-sulfopropyl)-imidazolium, 1-butyl-3-(3-sulfopropyl)-imidazolium) were synthesized and characterized. The characterization of BAILs was carried out using NMR, FTIR and elemental analysis (CHNS). The thermophysical properties of these ILs such as density, refractive index, viscosity and thermal stability were analyzed in wide temperature window. Furthermore, the effect of alkyl chain length of cations on thermophysical properties was well studied. The experimental values of density were further used to calculate other significant properties such as molar volume, standard molar entropy, lattice energy and thermal expansion coefficients. The Bronsted acidities of investigated ILs were determined using Hammett method. Furthermore, COSMO-RS study was performed to determine δ-surface, and δ-profile of the studied ILs.

In this study, four new protic ionic liquids (PILs), possessing camphorsulfonate anion with four different cations, 2-methyl-3-(3-sulfopropyl)-imidazolium (7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methanesulfonate [2MeimPS][CS], 2-ethyl-3-(3-sulfopropyl)-imidazolium (7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methanesulfonate [2EteimPS][CS], 2-phenyl-3-(3-sulfopropyl)-imidazolium (7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methanesulfonate [2PhimPS][CS] and 3-(3-sulfopropyl)-benzimidazolium (7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methanesulfonate [BnzimPS][CS] were synthesized and characterized. The effect of alkyl and aromatic substitution on the imidazolium cation was investigated in terms of fluctuations in density, viscosity and thermal degradation of ILs. The density and viscosity were determined within a broad temperature range and measured values of density were used to calculate molar volume, standard molar entropy, lattice energy and thermal expansion coefficients. The refractive indices were measured with an ATAGO refractrometer (RX-5000a) within the temperature range of 288.15–333.15 K. The studied ILs exhibited strong Bronsted acidities as determined by Hammett method. Three human pathogenic bacteria i.e. Escherichia coli E149 (EC), Staphlylococcus aureus S244 (SA) and Aeromonas hydrophilla A97 (AH), were deployed to investigate the toxicity behaviour of studied ILs and their 50% effective concentrations (EC50) were found in comparison with the least toxic imidazolium-based ILs. COSMO-RS was used to determine δ-surface, δ-potential and δ-profile of the investigated ILs.

Protic ionic liquids (ILs) with seven-membered azepanium cation were synthesized and characterized. The molecular structure of the synthesized ILs was confirmed using 1H NMR and 13C NMR spectroscopy. In one hand, sulfonic acid ( SO3H) group was tethered to the azepanium moiety combined with HSPO4 or H2PO4−anion and on the other hand azepanium based alkyl sulfate ILs were synthesized by reacting azepane with corresponding dialkyl sulfates. Thermo-physical properties (density, viscosity, glass transition temperature, thermal decomposition temperature) of the synthesized ILs were measured. All the studied ILs showed good thermal stability. From the viscosity and density data of alkyl sulfate ILs, the volumetric properties such as molar volume, lattice energy and standard molar entropy were calculated. COSMO-RS was used to predict hydrogen bonding energy, interaction energy, Van der Waals energy and H-bond accepting and H-bond donating nature of these pure ILs. Activity coefficient values have also predicted for these ILs with cellulose.

This present article covers a comparative study of esterification reaction using either ultrasound cavitation or conventional mechanical stirring with a series of newly developed SO 3 H-functionalized dicationic ammonium- and DABCO-based acidic ionic liquids. As a baseline for performance evaluation, esterification reaction was also conducted with a series of SO 3 H-functionalized monocationic ammonium-based acidic ionic liquids and several conventional mineral acids (H 2 SO 4 , etc.). Their efficacy as catalyst towards perceptive esterification for the synthesis of biodiesel from free long-chain fatty acids with methanol were appraised. The Hammett acidity of these conventional acids and acidic ionic liquids were also assessed using UV–visible spectroscopy. Four factors were studied in the process of optimizing the reaction conditions, which are methanol to oil molar ratio (3–15), catalyst amount (0.2–1.0%), temperature (25–60 °C) and time (0–60 min). Whereas esterification under mechanical stirring leads to formation of a triphasic system (methanol, ionic liquids and esters) easing final separation of components, the same reaction under ultrasonic irradiation leads to formation of one phase layer at the end of reaction but the esters were simply isolated using centrifugation. The results showed that whatever ultrasound or mechanical stirring, the use of dicationic ionic liquids authorized better conversion yields of free fatty acid (FFA) into fatty acid methyl esters (FAME) with better yields than with either monocationic ionic liquids or mineral acids. The novel ionic liquids together with the design of a clean procedure offers advantages including short reaction time, good yield, operational simplicity, and environmentally benign characteristics.

Over the past decades, Ionic liquids (ILs) have gained considerable attention from the scientific community in reason of their versatility and performance in many fields. However, they nowadays remain mainly for laboratory scale use. The main barrier hampering their use in a larger scale is their questionable ecological toxicity. This study investigated the effect of hydrophobic and hydrophilic cyclic cation-based ILs against four pathogenic bacteria that infect humans. For that, cations, either of aromatic character (imidazolium or pyridinium) or of non-aromatic nature, (pyrrolidinium or piperidinium), were selected with different alkyl chain lengths and combined with both hydrophilic and hydrophobic anionic moieties. The results clearly demonstrated that introducing of hydrophobic anion namely bis((trifluoromethyl)sulfonyl)amide, [NTF2] and the elongation of the cations substitutions dramatically affect ILs toxicity behaviour. The established toxicity data [50% effective concentration (EC50)] along with similar endpoint collected from previous work against Aeromonas hydrophila were combined to developed quantitative structure-activity relationship (QSAR) model for toxicity prediction. The model was developed and validated in the light of Organization for Economic Co-operation and Development (OECD) guidelines strategy, producing good correlation coefficient R2 of 0.904 and small mean square error (MSE) of 0.095. The reliability of the QSAR model was further determined using k-fold cross validation.

Highlights: • Addition of ionic liquid has impacts acoustic cavitation by increasing its efficiency. • Ionic liquid alkyl chain length effects the viscosity & surface tension of water. • Presence of ionic liquid may extend the life of radicals formed from sonolysis effect., This study investigates the potential of using small amounts of ionic liquids (IL) to enhance ultrasound-assisted extraction of lipids content from green microalgae. Three imidazolium-based ILs (butyl, octyl and dodecyl), each of them with two anions (bromide and acetate) were tested as additives. Viscosity and surface tension of the ILs aqueous mixtures were analyzed to determine the influence of ILs’ anions and alkyl chain length, whereas KI dosimetry experiments were used as an indicator of radicals formation. A key finding suggests that the small addition of ILs improves the ultrasonication either by enhancing the viscosity and reducing the water surface tension, leading to a more powerful acoustic cavitation process or by increasing HO° production likely to oxidize the microalgae cells membranes, and consequently disrupting them on a more efficient manner. KI dosimetry also revealed that long ILs alkyl chain is detrimental. This experimental observation is confirmed thus strengthened as the yield of extracted lipids from green microalgae has shown an incremental trend when the IL concentration also increased. These hypotheses are currently under investigation to spot detailed impact of ILs on cavitation process.

In this work, three novel imidazolium-based ionic liquids containing aromatic group in the cation combined with bis(trifluoromethylsulfonyl)imide anion were synthesized and characterized. Their thermophysical properties namely, density, viscosity, thermal decomposition, glass transition, and heat capacity were measured at various temperatures and atmospheric pressure. In addition, physicochemical properties such as molar volume (Vm) and crystal energy (UPOT) were also determined from the obtained density data. Novel group contribution parameters were obtained using Gardas and Coutinho model aiming at providing simple method to predict density and viscosity of ionic liquids.

The adsorption isotherms of two new ionic liquids (4-tert-butyl-1-propylpyridinium bromide: IL1 and (4-ter-butyl-1-(2 carboxyethyl) pyridinium bromide: IL2) and ibuprofen (2-[4-(2-methylpropyl) phenyl] propanoic acid: IBP) on an activated carbon cloth were studied at 286, 298 and 313 K. Experimental adsorption isotherms were simulated by a single energy monolayer model using statistical physics, allowing to determine the number of molecules per site ( n ), the density of receptor sites ( N M ) and the concentration at half saturation ( c 1/2 ). Simulation results suggested that two adsorbates were docked per receptor sites of the activated carbon cloth surface. As a function of temperature, the study of the monolayer adsorbed quantity has indicated that the adsorption process is exothermic. The magnitudes of the estimated adsorption energies have indicated that IBP and ILs have been physisorbed on the adsorbent. The conductor-like screening model for real solvents (COSMO-RS) was applied to calculate three specific interaction energies of ILs and IBP with a graphene layer, i.e., the electrostatic misfit energy (E MF ), the hydrogen-bonding energy (E HB ) and the Van der Waals energy (E vdW ). The COSMO-RS model has proved that the interaction of all the three studied adsorbates with a graphene layer mainly depends on the Van der Waals contribution. The highest interaction energies of IL2 and IBP with the carbon surface have been explained by the additional contribution of hydrogen bond attributed to the presence of a carboxyl group on these molecules.

Owing to their remarkable physical-chemical properties, Ionic Liquids are considered as very promising capturing/transportation fluids in biotechnological applications for gaseous pollutants such as Carbon dioxide (CO2) which can be then remediated by living microorganisms. However, Ionic Liquids are also toxic towards the majority of living species used for remediation purposes among green microalgae. In this study different ionic liquids were tested for their toxicity for different concentrations on one type of commonly used green microalgae, Botryococcus braunii. Ionic liquids bearing long alkyl chain do display higher CO2 uptake than ioni liquids analogue bearing shorter alkyl chain. This might explain why the production of biomass is dramatically enhanced with 1-octyl-1-Methyl Piperidinium bis (trifluoromethylsulfonyl) imide OMPip[NTf2] compared to 1-Butyl-1-Methyl Piperidinium bis(trifluoromethylsulfonyl) imide BMPip[NTf2] as the latter can supply more CO2 to the microalgae than the former leading to enhanced organism growth.

Ionic liquids (ILs) are molten salts that possess low melting points and wide solvation properties. ILs attracted the attention of the academic and industrial professionals due remarkable properties such as low vapor pressure and thermal stability which make them more environmentally friendly as they can replace volatile organic solvents (VOCs) in many organic reactions. This has brought attention to broaden this research area to overcome the harmful emissions from VOCs in industry. Pyridinium ILs have a wide range of applications in various domains such as material sciences, organic and bioorganic syntheses, biotechnologies, nanotechnology and Enhanced Oil Recovery (EOR). However, available toxicity data in literature is yet scarce and hampers a large scale development. In this study, 18 synthesized ILs were tested against guppy fish and four bacterial strains. Two gram negative bacteria: Salmonella enterica, Vibrio cholera and two gram positive bacteria: Listeria monocytogenes, Staphylococcus aureus were chosen to represent each category of bacteria . Fish test was conducted using OECD guidelines and the “96-well plate” procedure was adopted for the bacterial test using (CLSI M100-S24). Results showed that long alkyl chain length ILs showed higher toxicity than short alkyl chain analogs on all the targeted strains. The highest toxic effect exhibited by pyridinium ILs towards guppy fish was moderately toxic and the rest varied between relatively harmless and practically nontoxic. The highest antibacterial effect indicated slightly toxic effect towards Staphylococcus aureus obtaining EC 50 = 19.3 mg/L. In most cases, pyridinium ILs indicated relatively harmless and practically harmless effects towards bacteria after comparing the EC 50 values obtained with Passino and Smith 1987 hazard ranking.

Catalysis is important in various applications of organic chemistry and its output product control for stereoselective compounds is outrageous. Establishment of experimental facts of stereoselective compounds from catalysis and their validation using theoretical evidences is the key to understand various mechanisms of optically active compounds. A family of new ionic liquids (ILs) with various imidazolium cations and camphorsulfonate anion as environmentally benign liquid salts have been synthesized and deployed for catalysis of β-amino carbonyl compounds. The products were formed using ILs as a homogeneous catalyst with excellent product yield and diastereoselectivity. The effect of counter ions, Hammett acidity and viscosity of ILs along with solvent and temperature are explored in terms of reaction kinetics and product yields. Density functional theory (DFT) was used to investigate thermodynamical study of mechanistic pathway of the reaction. The DFT calculations predicted that the catalysis mechanism involved both counterions of the IL. Moreover, it is evidenced that the syn-pathway required lower activation energy while anti-pathway led to thermodynamically stable product. This study explores new avenues for using ILs as potential homogeneous catalysts for the production of stereoselective species.

The physicochemical properties including density, viscosity and refractive index of five ionic liquids (ILs) consisting of 2-acrylamido-2-methylpropanesulfonate [AMPS] as anion source with ammonium-based cations (tetrabutylammonium [TBA], tetrapropylammonium [TPA] and tetraethylammonium [TEA], tetramethylammonium [TMA] and (vinylbenzyl)trimethylammonium [vbn]) were measured and influence of these properties upon CO2 sorption was investigated. The viscosity and density measurements were taken at atmospheric pressure within the temperature range of (293.15–363.15) K, whereas refractive indexes were determined within (288.15–333.15) K. An increase in the side-carbon chain length of ammonium-based cations resulted in decreased density with a corresponding increase in viscosity and refractive index. Among the studied ILs, [TBA][AMPS] gave the highest viscosity and least density over the whole range of temperature and a higher CO2 sorption of 0.51 mol fraction at 298.15 K and 1 MPa was observed showing dependency of CO2 solubility on the thermophysical properties of studied ILs. Moreover, among investigated ILs, molar volume of [TBA][AMPS] was found to be largest (433.3729 cm3mol-1), which resulted in the higher amount of CO2 sorption in comparison to other investigated ILs. Also, Henry's constant of 1.51 MPa was found for [TBA][AMPS] which was 10.9, 33.4, 44.3 and 24.8% less than [TPA][AMPS], [TEA][AMPS], [TMA][AMPS] and [vbn][AMPS], respectively. The current work offers an in depth study to understand structure-activity relation between physicochemical properties and CO2 solubility of investigated ILs and explores the ways for enhanced CO2 sorption.

The antibacterial assay and Bronsted acidities of seven protic ILs bearing 1-ethyl-3-methyl imidazolium ([emim]), 1-butyl-3-methyl imidazolium ([bmim]), 1-benzyl-3-methyl imidazolium ([bnmim]), 1-butyl-1methyl pyrrolidinium ([bmpyr]), N-butyl pyridinium ([bpyn]), morpholinium ([mrph]) and (vinylbenzyl)trimethylammonium ([vbn]), as cation sources paired with 2-acrylamido-2- methyl-1-propanesulfonate ([AMPS]) anion were investigated. Escherichia coli E149 (EC), Aeromonas hydrophilla A97 (AH) and Staphlylococcus aureus S244 (SA) were used for toxicity determination of prepared ILs. Molecular docking studies were carried out for confirmation of binding interactions of molecules with the target complex. A good correlation was observed between experimental and theoretical results. The Hammett acidity functions of studied ILs were calculated from Hammett equation. Moreover, COSMO-RS computational study was done to study the cationic structural variations in studied ILs on the interaction of ILs with CO2. The current work offers a thoughtful understanding of acidity, toxicity and CO2 sorption of AMPS-based ILs to unfold the routes for their further synthetic, biological and environmental applications as promising applicants with multidimensional properties.

A series of five AMPS-based new ionic liquids (ILs) paired with different cations (thiazolium, ammonium, morpholinium, pyrrolidinium and iminium) has been synthesized and characterized by spectroscopic analysis. 3-Benzyl-5-(2-hydroxyethyl)-4-thiazolium [bnthia], (vinylbenzyl)trimethylammonium [vbn], morpholinium [mrph], 1-butyl-1-methylpyrrolidinium [pyrli] and (chloromethylene)dimethyl iminium [diMeimi] were used as cation moieties. DNA binding interactions, antioxidant assay and DFT studies have further been performed. The DNA binding analysis revealed that all the investigated ILs were able to electrostatically interact with DNA. None of the IL could intercalate into DNA. The DFT calculations predicted that [bnthia][AMPS] and [vbn][AMPS] may stabilize incoming electrons in their LUMO orbitals and can be radical scavenger. This prediction was supported by antioxidant assay using UV–Vis spectroscopy and cyclic voltammetry where DPPH radical scavenging by [bnthia][AMPS] and [vbn][AMPS] confirmed the DFT prediction. However, rest of the ILs did not scavenge DPPH free radicals.

The use of neoteric solvents to substitute organic molecular solvents offers new opportunities to develop more environmentally friendly synthetic organic chemistry to access to new molecules, materials or processes. Most known and investigated neoteric solvents (NS) remain nowadays supercritical fluids (SCF), room temperature ionic liquids (RTILS) and deep eutectic solvents (DES). Each of them offers several advantages over organic molecular solvents but also display inherent drawbacks. In order to tackle the latter moving forward to safer and faster processes, ultrasound technology was recently coupled synergistically with these new media. These three categories of NS are hereafter briefly introduced together with their own remarkable properties permitting their use as alternative benign solvents. Insights of striking developed applications with ultrasound will be then given in order to unleash the promising potential of coupling ultrasound technology with neoteric solvents.

The thermophysical properties such as density, refractive index, and viscosity of five aprotic ILs bearing imidazolium (1-ethyl-3-methylimidazolium [emim], 1-butyl-3-methylimidazolium [bmim], 1-benzyl-3-methylimidazolium [bnmim]), pyrrolidinium (1-butyl-1methylpyrrolidinium [bmpyr]), and pyridinium (N-butylpyridinium [bpyn]) cations with 2-acryloamido-2-methylpropanesulfonate [AMPS] anion were studied, and their effect on CO2 solubility was explored. The density and viscosity were determined within the temperature range of (293.15 to 363.15) K at atmospheric pressure, while refractive indices were measured within the temperature range of (288.15 to 333.15) K. Among imidazolium cations, increasing the side chain length resulted in increased refractive index and viscosity with a corresponding decrease in density. In the presented ILs, [emim][AMPS] showed the highest density and least viscosity over the entire temperature range and an enhanced CO2 dissolution of 0.40 mole fraction at 1 MPa was observed at 29...

A promising method of Carbon dioxide (CO2) valorization is to use green microalgae photosynthesis to process biofuel. Two Phase Partitioning Bioreactors (TPPBR) offer the possibility to use non-aqueous phase liquids (NAPL) to enhance CO2 solubility; thus making CO2 available to maximize algae growth. This requires relatively less toxic hydrophobic Ionic Liquids (ILs) that comprise a new class of ionic compounds with remarkable physicochemical properties and thus qualifies them as NAPL candidates. This paper concerns the synthesis of ILs with octyl and butyl chains as well as different cations containing aromatic (imidazolium, pyridinium) and non-aromatic (piperidinum, pyrrolidinium) rings for CO2 absorption studies. The authors measured their respective toxicity levels on microalgae species, specifically, Scenedesmus quadricauda, Chlorella vulgaris and Botryococcus braunii. Results revealed that octyl-based ILs were more toxic than butyl-based analogues. Such was the case for bmim-PF6 at double saturation with an absorbance of 0.11, compared to Omim-PF6 at 0.17, bmim-NTf2 at 0.02, and Omim-NTf2 at 0.14, respectively. CO2 uptake results for ILs bearing octyl-based chains compared to the butyl analog were 54% (nCO2/nIL) (i.e., moles of CO2 moles of IL) and 38% (nCO2/nIL), respectively. Conclusively, 1-butyl-1-methylpiperidinium absorbed 13% (nCO2/nIL) and appeared the least toxic, having an absorbance of 0.25 at 688 nm (double saturation at 7 d) compared to 1-butyl-3-methylimidazolium, which showed the highest toxicity with zero absorbance. Accordingly, these findings suggest that 1-butyl-1-methylpiperidinium is capable of transporting CO2 to a system containing green microalgae without causing significant harm; thus allowing its use in TPPBR technology.

Ionic liquids (ILs) are considered as emergent pollutants as their synthesis and further use at a large scale might generate environmental problems. The adsorption on activated carbons represents one of the most effective methods to remove ionic liquids and other micropollutants from wastewater. In this work, the adsorption properties on an activated carbon cloth of two pyridinium ionic liquids (4-tert-butyl-1-propylpyridinium bromide (IL1) and 4-tert-butyl-1-(2-carboxyethyl)pyridinium bromide (IL2)) newly synthesized, were compared with the ones of ibuprofen. The adsorption kinetics and isotherms were studied at pH 3 and 7.5. The adsorption thermodynamic parameters calculated from the isotherms indicate an exothermic process, typical of physisorption. The adsorption kinetics of a mixture of the molecules show a competition between ibuprofen and IL2. The location of each adsorbed ionic liquid and ibuprofen into the porosity of the activated carbon cloth was determined from N2 (at 77 K) and CO2 adsorption isotherms (at 273 K). The purification process of an effluent containing the ionic liquids and the ibuprofen in mixture or in single solute could be workable by adsorption on an activated cloth. Keywords: Adsorption, Kinetics, Isotherms, Activated carbon cloth, Ibuprofen, Ionic liquid

A new group of low viscosity hydrophobic trioctylammonium-based protic ionic liquids (PILs) with 2-naphthoate, 4-tert-butylbenzoate, 2-hexyldecanoate, and 4-phenylbutanoate anions were synthesized. All the synthesized PILs were liquids at room temperature. The PILs were characterized using nuclear magnetic resonance, elemental analysis, and Fourier transform infrared spectroscopy. Thermogravimetric analysis was conducted to determine the decomposition temperature of the PILs. The PILs were then subjected to thermophysical properties study where their densities, viscosities, refractive indices, and surface tensions were measured within the temperature range of 298.15 to 363.15 K at atmospheric pressure and correlated with established empirical equations. Other thermophysical properties such as molar volume, standard entropy, and lattice potential energy were determined using the measured density data whilst the surface excess energy and entropy were estimated using the measured surface tension data.

The thermal degradation of two ionic liquids (ILs) was investigated using thermogravimetric analysis (TG) to establish a relationship between the thermokinetics and thermal stability. N-butyl, N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [BMPyrro][NTf2] and N-octyl, N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide[OMPyrro][NTf2] were subjected to thermogravimetric analysis at varying heating rates of 5, 10 and 20 °C min−1 in the temperature range of 50–600 °C. The data obtained were analysed for thermokinetics using Ozawa, Kissinger and Starink methods using differential thermogravimetric (DTG) techniques, and Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS) and Starink methods using TG techniques. The results produced very high regression coefficients (R 2 ) values around 0.996, which exhibited that they were best fitted by the kinetics equations. The average calculated activation energy (E a) of [BMPyrro][NTf2] using FWO, KAS and Starink methods was 128.6, 123.6 and 124 kJ mol−1, respectively, and 113.7, 107.8 and 108.2 kJ mol−1, respectively, for [OMPyrro][NTf2] using same empirical methods. This emphasizes that the activation energy is strongly related to the length of the side alkyl chain of a given IL. In other words, the longer the side alkyl chain, the lower the activation energy. The E a trends with degree of conversion (α) suggest that a single mechanism without formation of intermediates or short-life intermediates was followed by the pyrolysis kinetics. This study introduced thermokinetics as a tool to study the thermal stability of ionic liquids.

Development of a simple route for the catalytic conversion of starch-based industrial waste (potato peels) and potato starch into reducing sugars was investigated in two ionic liquids for comparison – 1-allyl-3-methylimidazolium chloride [AMIM]Cl and 1-(4-sulfobutyl)-3-methylimidazolium chloride [SBMIM]Cl. Over a two hour period, a 20 wt% solution containing up to 43% and 98% of reducing sugars at low temperature in aqueous [SBMIM]Cl was achieved for the starch-based waste and the potato starch, respectively. In addition, the use of microwave and low frequency ultrasound to perform the depolymerisation of the raw starch-based material was explored and compared with conventional heating processes. peerReviewed

The viability of using ionic liquids (ILs) as extractive solvents to remove naphthalene (aromatics) and dibenzothiophene (DBT; Sulfur) from base oil by liquid-liquid extraction was investigated. The experiments were designed using Response Surface Methodology (RSM) with 1-butyl-3-methylpyridinium dicyanamide [BMPY][DCA], 1-butyl-3-methylimidazolium dicyanamide [BMIM][DCA], 1-butyl-3-methylimidazolium thiocyanate [BMIM][SCN] and 1-butyl-3-methylimidazolium dimethylphosphate [BMIM][DMP] ILs. The sulfur compound and aromatics were analyzed using Total Sulphur analyzer and High Performance Liquid Chromatography (HPLC) with high coefficient of determination i.e. R2 values of 0.964 and 0.997 respectively. The effects of different ILs, temperatures, and ILs to oil mass ratio (IL:Oil) were optimized.[BMPY][DCA] appeared as the most promising medium with 94.3% of dibenzothiophene and 83.1% of naphthalene removal after a single extraction step. The aromatics and sulfur removal efficiency of [BMPY][DCA] IL was 54.3%, 78.3% and 82.9%, 93.8% at IL:Oil ratios of 0.4 and 1.8, respectively. An increase in temperature did not improve the extraction efficiency, but a slight decrease was noted.Results emphasized that extraction of aromatics and sulfur compoundsfrom base oil can be achieved successfully using selected ionic liquids.

Due to their harmful effects on human's life and aquatic environments, designing easy and swift yet efficient methodologies to remove pollutants from water stream is one of the important tasks of the scientific community. Among the pollutants, dyes have a significant role on water pollution, because their presence, even in low concentration, impacts the aquatic life by preventing the photosynthesis process and it can be considered as toxic chemicals endangering the human's health. In this study three newly synthesized Task Specific Ionic Liquids (TSILs) incorporating different types of aromatic group on imidazolium ring namely, 1-Butyl-3-Benzoimidazolium bis(trifluoromethylsulfonyl)imide [BzBIm][NTf 2 ]; 1-Butyl-2-Phenyl-imidazolium bis(trifluoromethylsulfonyl)imide [BPhIm][NTf 2 ]; and 1-Benzyl-3-butyl-imidazolum bis(trifluoromethylsulfonyl)imide [BnBIm][NTf 2 ] have been employed to remove swiftly heavy loads (up to 1,500 ppm) of cationic Methylene Blue dye (MB) from aqueous solution without pH adjustment. The results showed that the presence of additional aromatic groups has a significant effect on the extraction efficiency of MB removal through enhancement of the π–π interactions between ILs and the aromatic structure of MB. Conductor-like Screening Model for Real Solvent (COSMO-RS) was used to analyse the IL-MB interaction in the studied systems. Finally, an original microbiological method has been designed not only to assess the toxicity of aqueous solution before and after the extraction process to reveal the industrial potential of this methodology but also to highlight the high hydrophobicity of these new TSILs.

Ionic liquids (ILs) are often touted as potential ‘green’ substitutes for volatile organic compounds in process chemistry. However, their often high solubility in water limits their applications since discharge of spent ILs into natural water bodies may have significant detrimental eco-toxicological consequences for aquatic organisms. This is especially true for most imidazolium and pyrdinium based ILs which have been proven as toxic to aquatic life organisms. The challenge is therefore to synthesize ILs which exhibit inherently low aquatic toxicity. In the present work, five choline based ILs pairing five different amino acid anions [Cho][AA] have been synthesized and characterized. Their thermal stability, density, viscosity and thermal expansion coefficient were reported. The toxicity behavior of a synthesized ILs were investigated on guppy fish ( Poecilia reticulate ) and three microbial species. Fish acute toxicity test reveal that the studied ILs could be classified as non-toxic while their 50% effective concentrations (EC 50 ) were found to be comparable to the least toxic imidazolium-based ILs.

The liquid-liquid extraction of Methylene Blue (MB) from aqueous solution was undertaken with 5 hydrophobic ionic liquids (ILs) based on bis(trifluoromethylsulfonyl)imide anion [NTf2] for comparison purpose where three of them were of commercial origin, 1-butyl-3-methyl imidazolium [BMIm], 1-hexyl-3-methylimidazolium [HMIm] and 1-octyl-3-methylimidazolium [OMIm] cations and the two other were purposely designed for this work, 1-hexyl-2-phenylimidazolium [HPhIm], and 1-benzyl-3-methyl-imidazolium [BnMIm]. Several parameters such as the place and nature of the aromatic ring, the length of the side alkyl chain and the ability to form hydrogen bonding were investigated to evaluate their impact on extraction performances. Results show that the incorporation of the functional group (aromatic group) not only led to excellent results of dye removal compared to commercially available ones but allowed easier recovery and subsequent reuse of the functionalized ILs. Conductor like Screening Model for Real Solvents (COSMO-RS) calculations were also performed to see the structural variations of the ILs their extraction capabilities of MB from water. The finding of this study may assist in reducing the pollution of wastewater from dye industries.

Ionic Liquid (IL), combination of an organic cation with an organic or inorganic cation, possess some remarkable physical chemical properties such as no virtual vapor pressure (allowing recyclability and reusability), wide liquid range, high thermal and chemical stability, ease to choose hydrophobic/hydrophilic character and wide electrochemical window. Owing to that, they have become increasingly popular as green solvents/additives/catalysts for organic synthetic chemistry, extraction, electrochemistry, catalysis, biomass conversion, biotechnologies and pharmaceutical applications. This is acknowledged by the exponential number of yearly published articles related to them. However, even if these are very widely studied in the international scientific community, they are not or very little used on an industrial scale, particularly because of the lack of data on their toxicity and biodegradability. Notably hydrophobic ILs seems to display higher toxicity towards microorganisms and lower biodegradability co...

Ionic liquids are no longer a curiosity since they have shown tremendous potential in several key sectors of chemical sciences proven by the exponential number of publications in recent years. However, due to its toxicity and time-consuming synthesis route, these have become a technical hurdle of their use in pilot or industrial scales. Notably their syntheses not only time and energy consuming but also rather of dirty nature with the use of molecular solvents for synthesis and purification steps, leading to high production cost and impeding the possible further industrial outcome. In this preliminary work, we have developed a neat and quick synthesis pathway of di-cationic ionic liquids, reducing not only the necessary time from days to minutes but also the overall energy consumption resulted in high purity, increasing their potential as green alternative to common molecular organic solvents.

Choline-Amino acid based ionic liquids (AAIL) have sparked recent interest throughout the scientific community due to their allegedly low cost and natural origin. They are considered as a potential “green” solvent to replace conventional volatile organic solvents. However, much is still scarce on their (AAILs) microbial toxicity and biodegradability. This study reports the synthesis of ten AAILs with cholinium cation and variable anions derived from amino acids. Their microbial biocompatibility to gram-positive (Bacillus licheniformis and Staphylococcus aureus) and gram-negative (Pseudomonas aeruginosa and Vibrio cholerae) bacteria and biodegradability by industrial sewage water were analyzed. All the tested AAILs were reported to have EC50 values in the range of 160-1120 mg/L which is deemed “practically harmless” based on hazard rankings. The toxicity trend was seen to reduce as the molecular weight of the anion decreased. The level of mineralization of AAILs through anaerobic microbial breakdown was found to be a factor of anion and its functional group in all the cases. They resulted to over 60% biodegradation in 28 days (readily biodegradable).

Dicationic ionic liquids are attractive new group of ionic liquids that acquire higher melting point, wider liquid range and better thermal stability. However, the exploration made on the utilization of these dicationic ionic liquids in any application is still limited. To the best of the author’s knowledge, this is the first review article that discuss about this new type of ionic liquids. This review describes about ionic liquids in general and gives a survey on the latest developments and progress concerning dicationic ionic liquids, from their classifications and properties to their employment in many applications.

Butylpyridinium thiocyanate [BuPyr]SCN ionic liquid was synthesized by metathesis and characterized. NMR spectrum has shown the [BuPyr] cation while FTIR has shown the SCN anion peak which confirms the structure of the synthesized ionic liquid. The ionic liquid was impregnated on activated carbon in order to enhance performance of sulfur dioxide adsorption compared to the non-impregnated raw activated carbon. Two types of activated carbons were used; activated carbon cylindrical granules and cloth. Different percentages of ionic liquid loading (1%, 10% and 20%) were applied. The capacity of the adsorbent for treatment of 10 ppm and 50 ppm SO2 was determined by breakthrough curve analysis whereby optimum breakthrough time was obtained. [BuPyr]SCN impregnated on activated carbon cloth have shown higher adsorption performance.

Non-conventional techniques, such as microwave (MW) and power ultrasound (US) as well as combined MW/US irradiation, have been used to promote one-pot synthesis of second-generation ionic liquids (ILs), cutting down reaction times and improving yields. However, the use of chloroalkanes in the alkylation of N -heterocycles requires more drastic conditions if results are to match those obtained with more reactive alkyl halides. The present paper describes a series of MW- or MW/US-promoted IL preparations starting from chloroalkanes and classic heterocycles (1-methylimidazole, pyridine and 1-methylpyrrolidine). When reactions were carried out under conventional heating in an oil bath they required longer reaction times and gave poorer yields. 1 H-NMR analysis and ion-exchange chromatography showed that the present solventless procedure afforded ILs of satisfactory purity. The observed high yields (usually 70-98% isolated), and short reaction times showed that a straightforward access to ILs can be also achieved with the use of alkyl chlorides, resulting in a considerable reduction of costs.

A new method for the benzoin condensation is proposed in imidazolium-based ionic liquids as solvents/catalysts. The use of a 30 kHz ultrasonic irradiation as activation method provides a quantitative yield of benzoin in 1-octyl-3-methyl-imidazolium bromide without degrading the ionic medium which can be-reused at least three times with no loss of activity.

International audience; Four new ionic liquids (ILs) based on 1-(2-hydroxyethyl-3-methylimidazolium) cation with glycinate, serinate, alaninate, and prolinate amino acid anions have been synthesized, and their thermo-physical properties (density, viscosity, surface tension, and heat capacity) were measured. Data were described using empirical expressions to determine other physical-chemical properties, such as molecular volume, standard molar entropy, and lattice energy. Moreover, acute toxicity tests toward Scenedesmus quadricauda (green algae) and Vibrio fischeri have been conducted. The high values obtained for the 50% effective concentration (EC50) indicated that these new ionic liquids can be considered eco-friendly. (C) 2015 Elsevier B.V. All rights reserved.

A series of new synthesized ionic liquids based on 1-octyl-3-methylimidazolium with glycinate, alaninate, serinate, prolinate, and asparaginate anions were prepared. Their thermophysical properties (density, viscosity, surface tension, and heat capacity) were measured at various temperatures and atmospheric pressures. Physicochemical properties such as thermal expansion coefficient values, molecular volume, standard molar entropy, and lattice energy standard were also determined using empirical methods. The effects of anions on the studied properties were further analyzed.

Tuning the characteristics of solvents to fit industrial requirements has currently become a major interest in both academic and industrial communities, notably in the field of room temperature ionic liquids (RTILs), which are considered one of the most promising green alternatives to molecular organic solvents. In this work, several sets of imidazolium-based ionic liquids were synthesized, and their toxicities were assessed towards four human pathogens bacteria to investigate how tunability can affect this characteristic. Additionally, the toxicity of particular RTILs bearing an amino acid anion was introduced in this work. EC50 values (50% effective concentration) were established, and significant variations were observed; although all studied ILs displayed an imidazolium moiety, the toxicity values were found to vary between 0.05 mM for the most toxic to 85.57 mM for the least toxic. Linear quantitative structure activity relationship models were then developed using the charge density distribution (σ-profiles) as molecular descriptors, which can yield accuracies as high as 95%.

A solventless benzoin condensation was performed with several imidazolium-based ionic liquids as catalysts under microwave irradiation. The process enables the formation of α-hydroxy-α-phenylacetophenone with good yield (up to 97%) and purity in a very short time. Moreover, the work-up only requires the use of water, giving a green touch to the overall process.

The use of ionic liquids (ILs) as a novel class of environmentally friendly solvents is now of topical interest among the chemical community, worried about the environmental impact of chemicals. Many reactions of organic chemistry have thus been re-examined since the 1990s. Nevertheless, even if a given preparation of ILs does not represent any particular difficulty, the reaction times appear to be long and the use of large amounts of classical solvents for the synthesis and the purification steps is crucial. This article presents preliminary work performed for the ultrasound assisted preparation of several 1-butyl-3-methylimidazolium salts (BF4, PF6, CF3SO3 and BPh4). In all cases a clear yield increase results and a dramatic reduction of the reaction time accompanied by an improved quality of the products occurs. After a short and simple work-up, the ILs are ready to use without a further purification step. Moreover, an original and simple analytical way to follow the reaction in real time is also presented.

Three 1-(2-hydroxyethyl)-3-alkylimidazolium chloride room temperature ionic liquids (ILs) [2OHimC(n)][Cl]; (n=0, 1, 4) have been synthesized from the appropriate imidazole precursors and characterized by IR and NMR spectroscopies and elemental analysis. Their anti-microbial activities were investigated using the well-diffusion method. The viabilities of Escherichia coli, Aeromonas hydrophila, Listeria monocytogenes and Salmonella enterica as a function of IL concentrations were studied. The minimal inhibitory concentrations (MICs) and EC₅₀ values for the present ILs were within the concentration range from 60 to 125 mM and 23 to 73 mM. The anti-microbial potencies of the present ILs were compared to a standard antibiotic, gentamicin. The finding affords additional perspective on the level of ILs toxicity to aquatic lifeforms and yet, this characteristic can be readily harnessed to detect microbial growth and activity.

Precipitation and liquid–liquid extraction of PtX62− (X = Cl−, Br−, SCN−) in acidified aqueous solutions ranging from 0.1 M to 9 M HBr or 11 M of HCl have been studied using water-soluble or hydrophobic ionic liquids. Divalent hexachloroplatinate(IV) anions appear to be extracted much less efficiently than tetrachloroaurate(III) complexes. At a concentration of 11 M HCl, values of 15 and 800 for the distribution coefficients of PtCl62− and PtBr62− in [OMIM][NTf2] have been obtained accordingly. The presence of a labile hydrogen on the imidazolium ring has been found to play a specific role in the extraction of platinum(IV) complexes in concentrated HCl or HBr. Pt(SCN)62− appears to be very efficiently extracted at pH 1 using [OMIM][NTf2], exhibiting a distribution coefficient of 6150. Finally, two methods for quantitative separation of gold and platinum in water using in each method two extraction steps have been proposed. The back extraction of platinum(IV) during the second separation process was also discussed.

Adsorption isotherms and kinetics of three ionic liquids (1-methyl-3-octylimidazolium chloride, 1-butyl-3-methylimidazolium chloride and N -octylpyridinium bromide) were studied on several types of activated carbon (AC) – a microporous granular AC (from China), a microporous–mesoporous AC fabric (Zorflex from Calgon) and an AC prepared from Artichoke leaves using phosphoric acid activation. ACs were characterized by N 2 adsorption measurement at 77 K (DFT pore size distribution), acido-basic titrations (Boehm method) and point of zero charge measurement. Isotherms were studied, using UV–visible spectrometry, in buffer solutions at pH = 2, 7 and 9, in the temperature range 20–50 °C. Kinetics models were found to be dependent on adsorbent type. Adsorption uptakes were correlated to the AC porous structures. The kind of interactions between organic cations and the carbon surface were found to be related to the amount of oxygenated groups and to the ionic liquid type. Presence of oxygen groups promoted electrostatic interactions which were stronger for the more hydrophilic cation (1-butyl-3-methylimidazolium). The calculated thermodynamic parameters showed that as compared to methylimidazolium, the adsorption of longer chain cations and pyridinium like cations was more favorable.

International audience; Five first generation ionic liquids (RTILs : BMImCl, OMImCl, AMImCl, BPyBr and OPyBr) were intercalated into the layered structure of a Na-montmorillonite by dispersion in aqueous solutions ([RTIL] ⩽ 20 mmol.L-1). For all ionic liquids, the intercalation expanded the spacing of the silicate layers, as measured by X-ray diffraction. FTIR, thermogravimetric analyses and sodium titrations of the solutions after intercalation proved the adsorption of the RTILs through a cation exchange mechanism. Adsorption isotherms, done at pH = 7 and at 25°C, displayed that the maximum adsorption capacity of the substrates was closely linked to the nature of the organic cation and the length of the alkyl chain (BPyBr > OPyBr ∼ AMImCl ∼ BMImCl > OMImCl). For the five RTILs, calculated parameters obtained from the adsorption isotherms studied at 3 temperatures (25°C, 40°C and 55°C) concluded to an endothermic and spontaneous adsorption reaction.

Bronsted-acidic ionic liquids that bear a sulfonic acid group, known as Forbes acids, show a good catalytic activity for the Beckmann rearrangement, used to prepare e-caprolactam, which is a precursor of Nylon 6. The activity essentially stems from the acidity of the sulfonic acid group. Although these task specific ionic liquids suffer from a high viscosity, this draw-back can be circumvented at higher temperatures. A combination of the hydrogen sulfate anion and the sulfonic acid group of the cation is needed to obtain the rearrangement product rapidly under mild conditions. When using an excess of ionic liquid, we postulate that the internal pressure of the ionic medium, generated by the high viscosity and the high number of hydrogen-bonds, is strong enough to contribute to a decrease of the thermodynamic barrier. In accordance with the "Principles of Green Chemistry," we have developed a synthesis of e-caprolactam that requires no additional chemicals except cyclohexanone oxime and the reusable TSIL.

An original route to 2-alkyamino-4-phenylquinazolines in three steps from simple (hetero)aromatic amines is reported here. The key step involves the intramolecular cyclization of benzoyl arylguanidines performed in [OMIm]Cl ionic liquid. The basic (hetero)aromatic guanidines deprotonate the imidazolium-based ionic liquid, thus triggering the cascade process ultimately leading to the intramolecular cyclization. This reaction is the first example of a Friedel-Crafts-type reaction in which an N-heterocyclic carbene is involved in the formation of the electrophilic intermediate.

The present work deals with the hydrodynamic behavior of several room-temperature ionic liquids presenting the same bis(trifluoromethanesulfonyles)imide anion, associated with four different cations: 1-butyl-3-methylimidazolium, 1-octyl-3-methylimidazolium, N-trimethyl-N-propylammonium and 1-butyl-1-methylpyrrolidinium cations. Steady state voltammetry was used as an electrochemical technique to characterize mass transfer in both silent and sonicated conditions, using a rotating disk electrode. Results obtained in RTILs media are compared to those acquired in synthetic solutions of controlled viscosity, in order to develop a better understanding of the phenomena involved in such media.

The synthesis of ionic liquids under non conventional activation methods is historically reviewed and completed with the recent developments of “one-pot” synthesis and combination of these activation methods.

A novel method is described for the one-pot synthesis of various ionic liquids in a competitive time. By using ultrasonic irradiation, different families of nitrogen-bearing ionic liquids can be obtained in a solvent-free or in aqueous medium, which gives a greener touch to the overall process.