Types Of Deep Eutectic Solvents Research Articles

Determination of Trifluoperazine hydrochloride in pharmaceutical preparations using Spectrophotometric method

Ionic liquids with discrete anions are deep eutectic solvents can be utilized formetals electroplating. In this investigation various types of deep eutecticsolvents have been utilized such as Reline, Ethaline and Hybrid as solvents forthe electrodeposition of Sn, Zn and Zn-Sn alloys. Ethaline and Reline displayedidentical voltammetric profiles for the reduction of Zn+2 and Sn+2. Relinepossess high viscosity which lead to decreasing the quality of electroplating,therefore the process needs higher temperature or longer electroplating time.The surface morphology and compositions have been characterized usingscanning electron microscopy (SEM) and elemental analysis by energydispersive X-ray Spectroscopy (EDX). These techniques lead to detecting themetal alloy that have been added to the ionic liquids. Pure ionic liquidspreparation was another aim of this investigation, which utilized as a standardscale for comparison with the metal based liquids. Analysis of cyclicvoltammetry in all systems indicated differences in the reactivity and mobility ofspecies in solution which affected the growth mechanism and resulted inchanges in deposit morphology.

Experimental Study of the Solubility of CO 2 in Novel Amine Based Deep Eutectic Solvents

Abstract In this study, we report new measurements of the solubility of carbon dioxide in three types of deep eutectic solvents (DESs), (Choline chloride + Monoethanolamine, ChCl-MEA), (Choline chloride + Diethanolamine, ChCl-DEA) and (Choline chloride + Methyldiethanolamine, ChCl-MDEA), which was determined at three different ChCl:amine molar ratios of 1:6, 1:8 and 1:10. The selected amines represent the primary, secondary and tertiary amines, respectively. The CO 2 absorption was conducted with a solvent screening set-up (SSS) and the CO 2 loading was measured with an ‘Elementar’ total organic carbon (TOC) analyzer. The solubility experiments were performed based on the conditions of the absorber in the post-combustion capture process (P CO2 = 15 kPa and T = 40 o C). Results revealed that amine-based DESs have absorption capacity that is much higher than both 30wt% aqueous amine solutions and conventional DESs. The solubility of CO 2 was found to increase as the molar ratio of the amine in the DES increased. ChCl-MEA absorbed the highest quantity of CO 2 while ChCl-MDEA absorbed the least.

Improving the production of propyl and butyl ester-based biodiesel by purification using deep eutectic solvents

This study provides an alternative biodiesel manufacturing process that is less energy intensive combined with a more environmentally benign purification step. This was achieved by replacing methanol as the traditional alcohol source with longer chain alcohols, namely propanol and butanol. These alcohols reduce mass transfer limitations resulting in high purities of fatty acid propyl ester (FAPE) and fatty acid butyl ester (FABE). Transesterification of soybean oil using long chain alcohols was conducted at a 6:1 (alcohol to oil) ratio, 0.66 wt% of sodium alkoxide catalyst and at room temperature for 5 mins. After evaporating the excess alcohol, the FAPE and FABE contents were found to be 81.7 wt% and 89.8 wt%, respectively. The propyl and butyl esters were then purified for first time by two different types of deep eutectic solvents (DESs), glycerol-based DESs (DES1 to DES3) and ethylene glycol-based DESs (DES4 to DES6). The results indicated that DES5 and DES6 were most effective for improving FAPE and FABE contents. They were successful in extracting the glycerol completely from FAPE and FABE at 3:1 DES:biodiesel ratio. Furthermore, molar ratios of 1:1 DES5:FAPE and 0.5:1 DES5:FABE were selected as minimum ratios for FAPE and FABE purification, which could fulfil the EN14214 and ASTM D6751 requirements for ester and glycerol contents. It was possible to recover 70% of choline chloride using acetone as anti-solvent, suggesting that deep eutectic solvents can be recycled.

Ultrasound assisted-deep eutectic solvent based on emulsification liquid phase microextraction combined with microsample injection flame atomic absorption spectrometry for valence speciation of chromium(III/VI) in environmental samples

A new type of deep eutectic solvents (DESs) have been prepared and used as extraction solvents for ultrasound assisted-deep eutectic solvent based emulsification liquid phase microextraction method (UA-DES-ELPME) for the determination and speciation of total chromium, chromium(III) and chromium(VI). The chromium concentration in DES rich phase (extraction phase) was determined by using microsample injection flame atomic absorption spectrometer (FAAS). The detection limit (LOD), the quantification limit (LOQ), preconcentration factor and relative standard deviation were found as 5.5µgL−1, 18.2µgL−1, 20 and 6%, respectively. The accuracy of the developed method was evaluated by the analysis of water the certified reference materials (TMDA-53.3 Fortified environmental water and TMDA-54.4 Fortified Lake Water) and addition-recovery tests for water samples.

Alternative Approach to Synthesize Methylated Chitosan Using Deep Eutectic Solvents, Biocatalyst and “Green” Methylating Agents

Conventional synthesis of N-methylated chitosan involves the use of organic solvents in alkaline conditions, using methyl iodide as the methylating agent. However, the method does not result in selective N-methylation and is known to cause heavy polymer scission. In this investigation, we have reported alternative “green” approaches for methylated chitosan synthesis. Two types of deep eutectic solvents (DESs), viz., DES(Urea) and DES(Gly), either alone or in combination with other solvents, were screened as media for facilitating the methylation of chitosan. Our results indicated that DESs mediated selective N-methylation in the absence of NaOH, with no polymer scission, when compared with the reported methods. 1H NMR spectra confirmed selective N-methylation in the case of products obtained using DES(Urea), while that obtained using DES(Gly) demonstrated some O-methylation. Another green method investigated the unexplored property of biocatalyst lipase for methylating chitosan in the presence of “green” ...

A facile and sustainable method based on deep eutectic solvents toward synthesis of amorphous calcium phosphate nanoparticles: The effect of using various solvents and precursors on physical characteristics

Amorphous calcium phosphate (ACP) nanoparticles were synthesized using a sustainable method based on precipitation of calcium and phosphate precursors in deep eutectic solvents (DESs). To this aim, three types of DESs, i.e., choline chloride–urea, choline chloride–ethylene glycol, and choline chloride–glycerol were prepared by simple heating-mixing method. The DESs were used as synthesis media for synthesis of ACP nanoparticles from Calcium nitrate tetrahydrate/calcium chloride and di-potassium hydrogen orthophosphate/di-ammonium hydrogen orthophosphate precursors. Characterization of the synthesized ACP nanoparticles by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy–selected area electron diffraction, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy confirmed the formation of amorphous nanoparticles with spherical morphology and a high elemental/structural purity. Based on the results, with the change of DES from choline chloride–urea to choline chloride–ethylene glycol the diameter and Ca/P molar ratio of ACP nanoparticles changed from 24 to 39nm, and 1.15 to 1.01 respectively. No significant changes in particle size of ACP nanoparticles were detected with change of precursors. After synthesis, DESs were recovered and re-used for synthesis of ACP nanoparticles. Analysis results suggested successful synthesis of ACP nanoparticles with high phase/elemental purity in the recovered DESs.

Analysis of operating conditions for CO2 capturing process using deep eutectic solvents

Selected types of deep eutectic solvents (DESs) were compared for designing CO2 capturing process. Specifically, the typical absorption–desorption process is examined. A mathematical model based on Peng–Robinson equation of state was developed to estimate the CO2 solubility and to determine the VLE conditions in the desorption unit. The comparison of the DES performance is based on the solvent requirement in the absorption unit and the temperature condition in the desorption unit. Ethanol amine based DES has shown the best performance when operating the absorber at 10bar and the stripper at 1bar. However, the simulation results indicate that in order to reduce the energy requirements in the regeneration process a large amount of solvent is needed. In fact, for 80% CO2 recovery the solvent intake rate should be at least 5 times the flue gas flow rate. Finally, we have shown that (i) the desorption energy required with MEA based DESs is much lower compared to the classical MEA process and that (ii) the energy required for compression remains the most important drawback for a such process, especially at low CO2 concentrations.

Utilization of deep eutectic solvents as novel mobile phase additives for improving the separation of bioactive quaternary alkaloids

Deep eutectic solvents (DESs) were used as novel mobile phase additives to improve chromatographic separation of four quaternary alkaloids including coptisine chloride, sanguinarine, berberine chloride and chelerythrine on a C18 column. DESs as a new class of ionic liquids are renewably sourced, environmentally benign, low cost and easy to prepare. Seven DESs were obtained by mixing different hydrogen acceptors and hydrogen-bond donors. The effects of organic solvents, the concentration of DESs, the types of DESs and the pH values of the buffer solution on the separation of the analytes were investigated. The composition of acetonitrile and 1.0% deep eutectic solvents aqueous solution (pH 3.3, adjusted with hydrochloric acid) in a 32:68 (v/v) ratio was used as optimized mobile phase, with which four quaternary alkaloids were well separated. When a small amount of DESs was added in the mobile phase for the separation of alkaloids on the C18 column, noticeable improvements were distinctly observed such as decreasing peak tailing and improving resolution. The separation mechanism mediated by DESs as mobile phase additives can be attributed to combined effect of both hydrogen acceptors and hydrogen-bond donors. For example, choline chloride can effectively cover the residual silanols on silica surface and ethylene glycol can reduce the retention time of analytes. The proposed method has been applied to determine BerbC in Lanqin Chinese herbal oral solution and BerbC tablet. Utilization of DESs in mobile phase can efficiently improve separation and selectivity of analytes from complex samples.

Deep eutectic solvent-mediated extraction for ligand-less preconcentration of lead and cadmium from environmental samples using magnetic nanoparticles

A simple, rapid and eco-friendly deep eutectic solvent-modified magnetic nanoparticles extraction method has been reported for ligand-less separation/preconcentration of lead(II) and cadmium(II) for the first time. The metal ions interact with the deep eutectic solvent adhering to the magnetic nanoparticles. Trapped analytes can be easily desorbed with 1.0 M nitric acid and determined by flame atomic absorption spectrometry. The effects of pH value, type of deep eutectic solvent, sample volume, nature and concentration of desorbing solution, ionic strength and extraction time on the extraction were optimized. Under the optimized experimental conditions, the detection limits (defined as 3Sb/m) were 0.4 and 0.1 μg L−1 and the linear dynamic ranges were 2 to 250 μg L−1 and 0.5 to 30 μg L−1 for lead and cadmium, respectively. The relative standard deviations for six replicate measurements at 150 and 20 μg L−1 levels of lead and cadmium were 1.8 and 2.1 %, respectively. A sample volume of 60 mL resulted in a preconcentration factor of 100. The sorbent showed high capacity for lead (25.0 mg g−1) and cadmium (23.7 mg g−1). The method was successfully applied to the determination of lead and cadmium in soil, hair and several water samples.

Magnetic graphene oxide modified with choline chloride-based deep eutectic solvent for the solid-phase extraction of protein

Four kinds of green deep eutectic solvents (DESs) based on choline chloride (ChCl) have been synthesized and coated on the surface of magnetic graphene oxide (Fe3O4@GO) to form Fe3O4@GO-DES for the magnetic solid-phase extraction of protein. X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (FESEM) and thermal gravimetric analysis (TGA) were employed to characterize Fe3O4@GO-DES, and the results indicated the successful preparation of Fe3O4@GO-DES. The UV–vis spectrophotometer was used to measure the concentration of protein after extraction. Single factor experiments proved that the extraction amount was influenced by the types of DESs, solution temperature, solution ionic strength, extraction time, protein concentration and the amount of Fe3O4@GO-DES. Comparison of Fe3O4@GO and Fe3O4@GO-DES was carried out by extracting bovine serum albumin, ovalbumin, bovine hemoglobin and lysozyme. The experimental results showed that the proposed Fe3O4@GO-DES performs better than Fe3O4@GO in the extraction of acidic protein. Desorption of protein was carried out by eluting the solid extractant with 0.005molL−1 Na2HPO4 contained 1molL−1 NaCl. The obtained elution efficiency was about 90.9%. Attributed to the convenient magnetic separation, the solid extractant could be easily recycled.

The novel use of Deep Eutectic Solvents for enhancing heavy oil recovery

Increasing demand and dwindling supply of crude oil have spurred efforts towards enhancing heavy oil recovery. Recently, applications of ionic liquids (ILs) for heavy oil recovery and catalytic upgrading have been reported. However, ILs are generally considered too expensive for industrial applications. Moreover, certain types of ILs are non-biodegradable and toxic. An alternative class of ILs called Deep Eutectic Solvents (DESs) have recently been discovered and investigated upon. A DES generally composed of two or more components that are capable of self-association, to form eutectic mixture with a melting point lower than that of each individual component. DESs are non-toxic, biodegradable, recyclable, non-flammable, environmentally friendly and cheap. Therefore, DESs have found application in fields like extraction/separation, solvent development/reaction medium, hydrometallurgy, etc. In this study, and for the first time to our knowledge, the effectiveness of two different types of DESs, Choline Chloride:Glycerol (1:2) and Choline Chloride:Urea (1:2), in enhancing heavy oil recovery was thoroughly investigated. Effect of the two DESs diluted with formation brine on emulsification, altering wettability, spontaneous imbibitions, surface and interfacial tensions and tertiary residual heavy oil saturation reduction are studied experimentally at different temperatures. Heavy oil with 16 ˚API and formation brine from one of the Omani heavy oil field were utilized. The core flood experiments were conducted at reservoir condition and using Berea sandstone core plugs. The results showed that the two DESs did not make emulsion with the heavy oil. They increased the IFT of oil-brine system. Moreover, the two DESs altered the wettability of the sandstone rock surfaces from liquid-wetting towards intermediately air-wetting conditions at oil-air-rock system. The core flooding runs at different temperatures showed high potential of using these DESs for enhancing heavy oil recovery; where 14–30% of water flooded residual heavy oil was recovered after injecting the DES solvents as tertiary recovery stage. Wettability alteration phenomenon and viscose forces were known as the main mechanisms of enhancing the heavy oil recovery by DESs injection.

One-pot electrochemical gram-scale synthesis of graphene using deep eutectic solvents and acetonitrile

Interest in the exfoliation of graphite to prepare few layer graphene (FLG) has seen significant growth. The electrochemical procedure has, unfortunately, remained rather elusive to scaling-up options. This work builds on recent results of employing acetonitrile (ACN) as a solvent for reducing the amount of expensive ionic liquids (ILs) used as electrolytes. In order to move towards a more environmentally friendly synthesis route, the yield and energy consumption of graphene exfoliation using the four main types of deep eutectic solvents (DESs) has been investigated. Best performance, in terms of the highest specific yield (graphene weight per unit energy consumed) of 0.307g/kJ, is observed when Type IV DES is employed as the electrolyte in ACN. Similar results, but with less specific yield, is observed when Type I DES is used (other DESs and the IL, BMPyrrBTA, did not provide high yields of graphene but produced more carbonaceous particles and rolled sheets instead). The physicochemical properties of the DESs also confirm that the best DES for exfoliation is the Type IV variant, which needs further investigation. The quality of graphene produced is excellent (4–5 layers, 80% transparency, specific surface area of 180m2/g, conductivity of 2.1×105S/m and a contact angle of 94° thereby displaying hydrophobicity) and comparable to most graphene produced via other means. While maintaining high quality, the application of ACN and DES is economically attractive compared to other methods.

Acoustic investigation of choline chloride based ionic liquids analogs

Despite the surge in publications related to the characterization of deep eutectic solvents (DESs), the speed of sound of these liquids was not considered. This work represents the first study to report the acoustic properties of choline chloride-based DESs (Type III). Five different hydrogen bond donors were used to synthesize the DESs and the speed of sound was measured as a function of temperature within the range: 293.15–353.15K. In general the speed of sound was affected by the nature and molecular structure of the DES considered. A general decrease in the speed of sound with temperature was noticed for all studied DESs. Three different models were attempted to correlate the speed of sound with some basic physical properties of these DESs as well as the temperature. The Gorbachev's model was able to correlate the speed of sound for the examined DESs with an overall relative error of 0.273%. Further work needs to be done on characterizing other types of DESs (Types I, II and IV) as well as relating the speed of sound data to other physical and thermodynamic parameters.

Solubility of CO2 in deep eutectic solvents: Experiments and modelling using the Peng–Robinson equation of state

Carbon dioxide capture and sequestration is drawing increasing attention as a potential method for controlling greenhouse gas emissions. Low cost ionic liquid analogues, namely, deep eutectic solvents (DESs), have attracted more attention for use in a diversity of applications. DESs exhibit many favourable properties, such as availability, non-toxicity, biodegradability, recyclability, non-flammability, and low price.In this work, phosphonium- and ammonium-based DESs with different hydrogen bond donors (HBD) have been synthesised. Then, the CO2 solubility in the synthesised DESs at a fixed pressure and temperature was determined, experimentally. Furthermore, a mathematical model based on the Peng–Robinson (PR) equation of state (EoS) was developed to correlate the CO2 solubility in these types of DESs. The model was validated with the obtained experimental data and tested with other specific DESs reported in the literature over a wide range of temperature and pressure values. In general, there was a good agreement between the experimental data and the calculated data using PR EoS. The obtained model can be utilised to study the effectiveness of using DES in CO2 capturing processes or any other separation processes.

Chemoselective synthesis of xanthenes and tetraketones in a choline chloride-based deep eutectic solvent

Abstract A chemoselective synthesis of tetraketone and xanthene derivatives, by means of tandem Knoevenagel condensation and Michael addition in choline chloride-based deep eutectic solvents (DESs), is presented. The reaction of readily available aldehydes and active methylene compounds in malonic acid- and ZnCl 2 -based DES gives various xanthenes derivatives with good to excellent yields under mild reaction conditions. On the other hand, tetraketones were synthesized in almost quantitative yields by simple condensation of an aldehyde and active methylene compounds in milder deep eutectic solvents of urea and SnCl 2 . In addition, the reaction of other types of choline chloride-based DES leads to a mixture of tetraketone and xanthene.

Electrodeposition of some metals and their alloys using different deep eutectic solvents based on choline chloride

Ionic liquids with discrete anions are deep eutectic solvents can be utilized for metals electroplating. In this investigation various types of deep eutectic solvents have been utilized such as Reline, Ethaline and Hybrid as solvents for the electrodeposition of Sn, Zn and Zn-Sn alloys. Ethaline and Reline displayed identical voltammetric profiles for the reduction of Zn+2 and Sn+2. Reline possess high viscosity which lead to decreasing the quality of electroplating, therefore the process needs higher temperature or longer electroplating time. The surface morphology and compositions have been characterized using scanning electron microscopy (SEM) and elemental analysis by energy dispersive X-ray Spectroscopy (EDX). These techniques lead to detecting the metal alloy that have been added to the ionic liquids. Pure ionic liquids preparation was another aim of this investigation, which utilized as a standard scale for comparison with the metal based liquids. Analysis of cyclic voltammetry in all systems indicated differences in the reactivity and mobility of species in solution which affected the growth mechanism and resulted in changes in deposit morphology. Keywords