Binary Deep Eutectic Solvents Research Articles

Molecular Dynamic Simulation of the Interaction of a Deep Eutectic Solvent Based on Tetraethylammonium Bromide with La3+ in Acidic Media

In recent years, noticeable progress has been made in the development of alternative extraction systems characterized by greater sustainability. In this context, deep eutectic solvents (DESs) have emerged as a promising alternative to the conventional solvents commonly used in metal extraction. This work focuses on investigating the extraction of lanthanum in an aqueous solution of sulfuric acid using a deep eutectic solvent, employing molecular dynamics simulations (MD). The structural characteristics of the solvent and its interactions with the components of the aqueous solution are explored. In this study, tetraethylammonium bromide (TEABr) is combined with ethylene glycol (EG) to form a DES, in which sodium cyanide (NaCN) is subsequently solubilized. According to the results obtained from the MD simulation, the primary interactions in the DESs are established through hydrogen bonds between the bromine and the hydrogens of the methyl group of tetraethylammonium at 3.5 Å, as well as between the bromine and the hydrogens of the methylene group of ethylene glycol at 3.5 Å. Similarly, the main interactions between the binary DES and sodium cyanide occur through the hydrogens of the hydroxyl group of EG and the carbon of cyanide at 1.7 Å, and between the oxygen of the hydroxyl group of EG and the sodium at 2.5 Å. In the acidic solution, the primary interaction is highlighted between the lanthanum ion and the oxygen of the bisulfate at 2.8 Å. Additionally, it is observed that the interaction between the DES and the aqueous solution occurs between the lanthanum and the oxygen of the hydroxyl group of EG, as well as between the lanthanum and the carbon of cyanide at 4.4 Å. It is important to note that, when increasing the temperature from 25 to 80 °C, the interaction distance between the lanthanum and the carbon of cyanide decreases to 2.4 Å, suggesting a possible correlation with the increase in lanthanum extraction, as experimentally observed. Overall, this study underscores the importance of considering the fundamental structural interactions of the DES with the lanthanum acid solution, providing an essential theoretical basis for future experimental investigations.

Efficient Absorption of CO2 by Protic-Ionic-Liquid Based Deep Eutectic Solvents.

Carbon capture, utilization, and storage (CCUS) are among the key technologies to achieve large-scale carbon emission reduction globally. Deep eutectic solvents (DESs) are considered as designable solvents, which has attracted intensive attention for CO2 capture. Here, a series of binary DESs are synthesized through one-step mixing with the starting materials of protic ionic liquid (PIL) and amine. The eutectic behavior was investigated by measuring the melting point of PILs and amine. The saturated vapor of these DESs and industrial MDEA solution were measured and compared. These DESs are investigated to have high absorption capacity (0.1 g ⋅ g-1 at 1.0 bar and 25 °C), superior apparent absorption rate constant (0.381 min-1 vs 0.012 min-1 of 70 wt.% MDEA), moderate interaction with CO2 (the enthalpy change is as low as -34.8 kJ ⋅ mol-1). The absorption mechanism is also investigated by NMR analysis. Eight absorption/desorption regeneration experiments are carried out to show their reversibility. Considering the advantages, including convenience of synthesis, large absorption capacity, fast absorption rate, and moderate interaction energy as well as good regeneration, these DESs are believed to be as potential CO2 absorbent in practical applications.

Investigation of the effects of ternary deep eutectic solvent composition on pretreatment of sorghum stover

AbstractBiomass‐derived deep eutectic solvents (DESs) have been introduced as promising pretreatment and fractionation solvents because of their mild processing conditions, easy synthesis, and green solvent components from biomass. In recent DES studies, solvent‐based third constituents like water, ethanol, and others improve the processibility of typical binary DESs. However, the impacts of these components are not well understood. Here, two solvent‐based constituents, including water and ethylene glycol, were applied to 3,4‐dihydroxybenzoic acid (DHBA)‐based DES system for improving the conversion efficiency of cellulose‐rich fraction and the properties of lignin fraction. Chemical composition, enzymatic digestibility, degree of polymerization of cellulose and physicochemical properties of lignin were used to evaluate the impact of each third constituent on biomass processing. Ternary ChCl‐DHBA DESs exhibited better performances in delignification, fermentable sugar production, and preservation of β‐O‐4 ether linkage in lignin compared with binary ChCl‐DHBA DES.

ZnCl2:ChCl:2urea as a new ternary deep eutectic for clean production of high content zwitterionic micro- or nano-cellulose by passing to the binary DES of ZnCl2:2urea

Deep eutectic solvents (DESs) are clean alternatives for chemical reagents and reaction media. Herein, a novel method for zwitterionzation of micro-/nano-cellulose (MC/NC) by a novel ternary DES (TDES) from ZnCl2, choline chloride (ChCl), and urea was established. In the characterized TDES of ZnCl2:ChCl:2urea, by phase diagram, viscosity, density, FT-IR, and TGA analyses, ZnCl3−Ch+ is hydrogen bond-acceptor (HBA) and two urea molecules are hydrogen bond-donors (HBDs). The theoretical investigations on donor–acceptor mechanism by Functional Density Theory, the reduced density gradient isosurface, and electrostatic potential surface (EPS demonstrate the co-existences of the H-bonding and electrostatic-interactions in formation of ZnCl2:ChCl:2urea. These interactions between ZnCl3−Ch+ complex as HBA and urea HBDs provide a higher equilibrium than the related binary DESs. By this new TDES, alkalized MC or NC was zwitterionized without any additional reagent and the products were characterized by FT-IR, FESEM, EDX, PZC, TGA, and XRD analyses. Dual positively/negatively sites on cellulose and decrease in crystallinity-index (7%) and thermal-stability detected for the given zwitterionized celluloses. In this new protocol, the simply prepared ZnCl2:ChCl:2urea served as both of reaction medium for dissolution of cellulose and cholinating agent for the zwitterionization of cellulose by nucleophilic attack of the alkalized MC/NC to activated-ChCl by TDES.

Critical Properties of Ternary Deep Eutectic Solvents Using Group Contribution with Extended Lee-Kesler Mixing Rules.

One of the most commonly used molecular inputs for ionic liquids and deep eutectic solvents (DESs) in the literature are the critical properties and acentric factors, which can be easily determined using the modified Lydersen-Joback-Reid (LJR) method with Lee-Kesler mixing rules. However, the method used in the literature is generally applicable only to binary mixtures of DESs. Nevertheless, ternary DESs are considered to be more interesting and may provide further tailorability for developing task-specific DESs for particular applications. Therefore, in this work, a new framework for estimating the critical properties and the acentric factor of ternary DESs based on their molecular structures is presented by adjusting the framework reported in the literature with an extended version of the Lee-Kesler mixing rules. The presented framework was applied to a data set consisting of 87 ternary DESs with 334 distinct compositions. For validation, the estimated critical properties and acentric factors were used to predict the densities of the ternary DESs. The results showed excellent agreement between the experimental and calculated data, with an average absolute relative deviation (AARD) of 5.203% for ternary DESs and 5.712% for 260 binary DESs (573 compositions). The developed methodology was incorporated into a user-friendly Excel worksheet for computing the critical properties and acentric factors of any ternary or binary DES, which is provided in the Supporting Information. This work promotes the creation of robust, accessible, and user-friendly models capable of predicting the properties of new ternary DESs based on critical properties, thus saving time and resources.

Extreme-environment-adapted eutectogel mediated by heterostructure for epidermic sensor and underwater communication

In recent years, gel-based ion conductor has been widely considered in wearable electronics because of the favorable flexibility and conductivity. However, it is of vital importance, yet rather challenging to adapt the gel for underwater and dry conditions. Herein, an anti-swelling and anti-drying, intrinsic conductor eutectogel is designed via a one-step radical polymerization of acrylic acid and 2, 2, 2‑trifluoroethyl methacrylate in binary deep eutectic solvents (DESs) medium. On the one hand, the synergistic effects of hydrophilic/hydrophobic heteronetworks can elicit the integrity stability of eutectogel in liquid environment. It is proved that both the mechanical property and conductivity are maintained after immersing in different salt, alkaline and acid solution and organic solvent for one month. On the other hand, the eutectogel inherits well conductivity (93 mS/m), anti-drying and antibacterial properties from DESs. Based on the above features, the resulting eutectogel can be assembled as smart sensor for stable information transmission in air and underwater with fast response time (1 s), high sensitivity (Gauge factor = 1.991) and long-time reproducibility (500 cycles, 70 % strain). Considering the simple preparation and integration of multiple functions, the binary cooperative complementary principle can provide insights into the development of next-generation conductive soft materials.

Ternary choline chloride/benzene sulfonic acid/ethylene glycol deep eutectic solvents for oxidative desulfurization at room temperature.

Deep eutectic solvents (DESs) have been extensively studied as promising green solvents to attain a better removal efficiency of sulfide. A new DES system formed from choline chloride (ChCl), benzene sulfonic acid (BSA), and ethylene glycol (EG) as a class of ternary DESs was prepared and used in the oxidative desulfurization (ODS) of different sulfides. Ternary DESs have distinct advantages such as volatility and high activity compared with organic acid-based binary DESs. Under the optimum conditions with VDES/VOil = 1 : 5, O/S (molar ratio of oxygen to sulfur) = 5, and T = 25 °C, the desulfurization efficiencies of dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), and benzothiophene (BT) were all achieved to 100% in 2 h. Through experimental and density functional theory (DFT) calculation methods, this new system as a class of ternary DESs shows good stability and excellent desulfurization performance at room temperature. The investigation of this study could supply a new idea of ternary DESs for oxidative desulfurization.

Efficient and selective absorption of SO2 by low-viscosity matrine-based deep eutectic solvents

Designing excellent liquid absorbents with low viscosity for efficient and selective absorption of sulfur dioxide (SO2) from flue gas is important but still challenging. Herein, matrine-based binary deep eutectic solvents (DESs) were prepared by mixing matrine (Mat) with three different amides including N-methylformamide (MFA), N-ethylformamide (EFA), and N-methylacetamide (MAA). It is found that the viscosities of these three DESs were lower than 20 cP at room temperature, which is significantly lower than other previous DESs or ILs that have been reported. Moreover, the results of SO2 capture showed that the absorption rate of SO2 by the Mat-MFA (1:2) DES was very fast (<3 min) to achieve a relatively large absorption capacity (0.84 g/g at 293.2 K and 1 bar). Mat-MFA (1:2) DES also displayed very high selectivity (576) for the SO2/CO2 (10/90, v/v) mixture, which is higher than most of the liquid absorbents and solid adsorbents currently reported. Furthermore, breakthrough experiments verified the good separation performance of Mat-MFA (1:2) DES in capturing 2% SO2 in the mixture of SO2/N2 or SO2/CO2, respectively. The results illustrated that the features of low viscosity, fast absorption rate, and high selectivity of SO2 capture make the matrine-based DESs have great potential for flue gas desulfurization.

Sustainable chitosan packaging films: Green tea polyphenolic extraction strategies using deep eutectic solvents

In this work, an alternative approach towards the use of a ternary natural deep eutectic solvent (ChCl/glycerol/lactic acid: NADES-3) as an environmentally friendly medium for the extraction of polyphenolic compounds from green tea (GT) was investigated. The ternary NADES have a higher capacity of polyphenolic extraction in comparison with the other two binary NADES (NADES-1 and NADES-2, ChCl/glycerol and ChCl/Lactic acid, respectively). The extraction GT solutions were used to improve chitosan (Chit) film properties, using the casting method, to produce films with and without different GT/NADES (ternary and binary) plasticizers. Transparent, uniform, and homogeny films (without cracks or pores) were obtained and evaluated in terms of mechanical, water resistance, optical and microstructural properties. The results were compared with those obtained for chitosan films containing binary deep eutectic solvents (ChCl/glycerol and ChCl/lactic acid, with and without GT)) as plasticizers in their formulations. In this sense, the presence of GT polyphenolic compounds led to different surface structures, and the surface of the biofilms become rougher with the increase of GT content. FTIR spectra confirmed physical entanglements film components and suggested the existence of the interaction between the extract's polyphenols and the Chit matrix. Films with 10% of NADES (binary and ternary) showed good high water barrier properties. Regarding mechanical properties, they also showed higher resistance, being the NADES-2 (10%) the film with better resistance.

Predicting the Surface Tension of Deep Eutectic Solvents: A Step Forward in the Use of Greener Solvents.

Deep eutectic solvents (DES) are an important class of green solvents that have been developed as an alternative to toxic solvents. However, the large-scale industrial application of DESs requires fine-tuning their physicochemical properties. Among others, surface tension is one of such properties that have to be considered while designing novel DESs. In this work, we present the results of a detailed evaluation of Quantitative Structure-Property Relationships (QSPR) modeling efforts designed to predict the surface tension of DESs, following the Organization for Economic Co-operation and Development (OECD) guidelines. The data set used comprises a large number of structurally diverse binary DESs and the models were built systematically through rigorous validation methods, including ‘mixtures-out’- and ‘compounds-out’-based data splitting. The most predictive individual QSPR model found is shown to be statistically robust, besides providing valuable information about the structural and physicochemical features responsible for the surface tension of DESs. Furthermore, the intelligent consensus prediction strategy applied to multiple predictive models led to consensus models with similar statistical robustness to the individual QSPR model. The benefits of the present work stand out also from its reproducibility since it relies on fully specified computational procedures and on publicly available tools. Finally, our results not only guide the future design and screening of novel DESs with a desirable surface tension but also lays out strategies for efficiently setting up silico-based models for binary mixtures.

Electropolymerisation of brilliant cresyl blue and neutral red on carbon-nanotube modified electrodes in binary and ternary deep eutectic solvents

Brilliant cresyl blue (BCB) and neutral red (NR) have been electropolymerized in binary and ternary deep eutectic solvents (DES) on glassy carbon electrodes (GCE) modified with multiwalled carbon nanotubes (CNT). The influence of binary and ternary DES composition on the polymer film properties was evaluated. Cyclic voltammetry and electrochemical impedance spectroscopy were used to characterise the PBCB and PNR films. PBCB/CNT/GCE and PNR/CNT/GCE platforms with polymer formed in ternary DES led to an improvement of the electrochemical properties of the modified electrodes compared to polymer synthesised in the corresponding binary DES. The second hydrogen bond donor tuned the DES characteristics, leading to a sensor platform with higher sensitivity. The PNR/CNT/GCE prepared in different binary and ternary DES were successfully tested for ascorbate sensing and demonstrated the applicability of the sensor architectures.

Photocatalytic oxidative of Keggin-type polyoxometalate ionic liquid for enhanced extractive desulfurization in binary deep eutectic solvents

A series of novel binary deep eutectic solvents (DESs) composed of choline chloride (ChCl) and formic acid (HCOOH) with different molar ratios have been successfully synthesized and applied in extractive desulfurization (EDS). Keggin-type polyoxometallate ionic liquid [TTPh]3PW12O40 was prepared and used as catalyst to enhance the EDS capacity by means of photocatalytic oxidative process. Both of the DESs and [TTPh]3PW12O40 ionic liquid catalyst were characterized in detail by Fourier transform infrared spectroscopy spectra (FT-IR), elemental analysis, and X-ray photoelectron spectroscopy (XPS). It was found that the molar ratios of ChCl:HCOOH had a major impact on desulfurization performance, and the optimal desulfurization capacity 96.5% was obtained by ChCl/5HCOOH. Besides dibenzothiophene (DBT), the desulfurization efficiencies of 4-methylbenzothiophene (4-MDBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT), two kinds of DBT derivatives, were also investigated under the same experimental conditions. Moreover, the free radical scavenging experiments manifested that superoxide radical (O2−) and hole (h+) played important roles in the desulfurization system. After further analysis of the oxidation products by gas chromatography-mass spectrometry (GC–MS), the possible reaction mechanism was proposed. Thus, photocatalytic oxidative has been proved to be one of the efficient approaches for enhancing the extractive desulfurization performance in DES.

Turning deep-eutectic solvents into value-added products for CO2 capture: A desirability-based virtual screening study

Carbon dioxide capture and storage is one of the primary mitigation approaches endorsed by current global climate change policies, since it is the largest contributing gas to the greenhouse effect. Recently, deep eutectic solvents (DESs) have been found as promising green solvents for CO2 capture, particularly in industrial applications. Compared to conventional ionic liquids, for example, DESs display similar solvent properties but they are far cheaper, easier to prepare, and greener. Yet their major drawback is linked to their high viscosity that impedes management not fulfilling industrial demands. Further efforts are thus required to develop new DES solvents that hold together high capacity for CO2 uptake and low viscosity. In this work, we adopted a desirability-based decision approach to jointly handle these two conflicting properties. We began by setting up Quantitative Structure-Property Relationships (QSPR) models for uncovering the two properties based on a dataset of known binary DESs. Then, desirability functions derived from the individual QSPR models were found and combined into an overall desirability-based criterion that was applied to screen and rank two libraries, one comprising experimentally reported DESs and another one with newly designed DESs. The latter enabled us to propose novel efficient DESs for CO2 uptake, i.e., with the most suitable trade-offs between CO2 absorption capacity and viscosity. Finally, but most importantly, this work demonstrates the usefulness of the desirability-based approach for the rational discovery of deep eutectic solvents or other materials to suit particular sustainable applications.

Effect of Water on a Hydrophobic Deep Eutectic Solvent.

Deep eutectic solvents (DESs) formed by hydrogen bond donors and acceptors are a promising new class of solvents. Both hydrophilic and hydrophobic binary DESs readily absorb water, making them ternary mixtures, and a small water content is always inevitable under ambient conditions. We present a thorough study of a typical hydrophobic DES formed by a 1:2 mole ratio of tetrabutyl ammonium chloride and decanoic acid, focusing on the effects of a low water content caused by absorbed water vapor, using multinuclear NMR techniques, molecular modeling, and several other physicochemical techniques. Already very low water contents cause dynamic nanoscale phase segregation, reduce solvent viscosity and fragility, increase self-diffusion coefficients and conductivity, and enhance local dynamics. Water interferes with the hydrogen-bonding network between the chloride ions and carboxylic acid groups by solvating them, which enhances carboxylic acid self-correlation and ion pair formation between tetrabutyl ammonium and chloride. Simulations show that the component molar ratio can be varied, with an effect on the internal structure. The water-induced changes in the physical properties are beneficial for most prospective applications but water creates an acidic aqueous nanophase with a high halide ion concentration, which may have chemically adverse effects.

Understanding the bulk and interfacial structures of ternary and binary deep eutectic solvents with a constant potential method: a molecular dynamics study

In the last decade, deep eutectic solvents (DESs) have emerged as promising electrolytes in supercapacitors and rechargeable batteries due to their unique properties, wide electrochemical windows, low viscosity, and high ionic conductivity. The molecular structural behavior of these solvents, which plays an important role in their efficiency is not deeply understood. Therefore, in this work, by considering two types of DES electrolytes, we investigate their bulk and interfacial structures at the molecular level using molecular dynamics studies. In this regard, two different DESs-a binary DES including choline chloride and urea in a 1 : 2 molar ratio, and a ternary DES containing choline chloride, urea, and ethylene glycol with a molar ratio of 1 : 1 : 2-are considered. For the bulk phase, the partial site-site and center of mass radial distribution functions (RDFs), the mean square displacement (MSD), and the self-diffusion coefficient of the ternary system are explored. We demonstrate that in deep eutectic solvents, in addition to hydrogen-bonding and long-range and short-range correlations, a variety of neutral species play crucial roles in the properties of the bulk phase. Furthermore, considering two graphene sheets as electrodes on both sides of the DES samples, the profiles of the number density, charge density, orientational order parameter, and electrostatic potentials at different potential conditions near the electrodes are investigated. The results reveal the presence of multilayers of the neutral species in the vicinity of electrodes in addition to the ionic components of both DES systems. Finally, the computed differential capacitances (Cd) for DESs disclose that the positive electrode capacitance is higher than that of the negative electrode, and in the ternary system, the total capacitance is greater than in the binary system. Our findings give a better perspective of a new generation of electrolytes at the molecular level for electric double-layer capacitors.

Synthesis of task-specific ternary deep eutectic solvents for deep desulfurization via reactive extraction

Deep eutectic solvents (DESs) are a new type of green solvents, which have received widespread attention due to their similar nature to that of ionic liquids. They are generally composed of two or more components through physical interaction. In this work, a series of three-component DESs were synthesized by simple mixing of three components including boric acid, ethylene glycol and choline-like quaternary ammonium salt (2-hydroxyethyl)-n-alkyl-dimethylammonium chloride ([CnDMEA]Cl) with different molar ratios, where the alkyl group (Cn, n = 4, 8, 12) represented different lengths of carbon chain. The characterization results of DESs through FT-IR and 1H NMR showed that DESs were formed by hydrogen bonding interaction. Extractive desulfurization combined with oxidation was established, where DESs were used as not only extractant but also catalysts. Compared with binary DESs, the ternary DES [C4DMEA]Cl/H3BO3/EG (1:3:5) showed higher catalytic activity in desulfurization of fuel, and the sulfur removal could reach up to 95.3% under optimized reaction conditions. Moreover, the high extraction efficiency of DESs was beneficial to their oxidation of the sulfur compounds. The reaction mechanism was studied by electron spin-resonance spectroscopy test and radical capture experiment.

Synergy of high permeability and selectivity of superbase/choline chloride/urea solution impregnated membranes for CO2 capture

A new generation of solvents called ternary deep eutectic solvents have emerged as a promising candidate to replace ionic liquids (IL) in CO2 capturing due to its inherent advantages of both, superbase and deep eutectic solvents (DES). In this work, the binary and ternary DES were synthesized to investigate the effect of superbase on the performance of DES based membrane systems for acid gas capture. The reline DES system was chosen as binary DES and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was used as superbase. The ternary DES was prepared by mixing DBU in reline DES system in different molar ratios. The permeability and selectivity of the synthesized membrane for CO2, CH4, and N2 were investigated in pure and mixed gas experiments. Moreover, the effect of the DES molar ratio, operating conditions of feed on the DES based supported liquid membranes (SLMs) performance was studied comprehensively. These novel ternary DES SLMs showed significant permeability and selectivity values up to 38.12 Barrer and 58.65 respectively. These values were found to be significantly higher than the permeability and selectivity value of binary DES-SLM i.e. 31 Barrer and 51.67 respectively. The improved gas performance results of ternary DES can be attributed to the basicity and fast reaction kinetics of the superbase/DBU. The ternary DES can potentially alternate the ILs and commonly used binary DESs in CO2 capturing process due to their high affinity towards CO2 gas.

Molecular dynamics of binary deep eutectic solvents as biocompatible working fluids in heat and mass transfer systems

Non-biocompatibility, volatility, toxicity, and corrosiveness are associated with conventional working fluids in heat and mass transfer systems. These issues can be mitigated using binary deep eutectic solvent (DES) fluids. This study aims to characterize and evaluate different DES as bio-working fluids. Eleven binary DES samples were prepared by mixing different ratios of compounds and then classified into four groups. Group DES A was developed from C5H14ClNO and (CH2OH)2, DES B from C6H16ClNO and (CH2OH)2, DES C from C8H15ClN2 and ZnCl2 (CH2OH)2, and DES D from C8H15ClN2 and (CH2OH)2. The molecular structures of each category of binary DES were built using the BIOVIA material studio software 6.0 (ACCELRYS). The samples' molecular dynamics, rheology and physiochemical properties were numerically evaluated to predict the material's profile. The chemical fingerprint, inter-molecular behavioral properties, functional groups, rheology, thermal stability, conductivity, electrophoretic properties, and possible emissions at elevated temperatures of the samples have been evaluated. The measured viscosities of the eleven samples, between 0.015 and 0.04 Pa∙s are low compared to conventional ionic liquids and some nanofluids reported in the literature. The average thermal conductivity of the investigated binary DESs was between 0.228 and 0.17 W/m·K at 25 °C. Group DES C thermally decomposes after 350 °C, while other DESs exhibited thermal stability until about 150 °C. Additionally, toxicity analyses of the DESs revealed their bio-friendliness. This property is owed to the emitted compounds with health benefits, including triacetin, procainamide, monoacetate, and 2, 2 difluoroethyl acetates, witnessed at 250 °C of injection temperature.

Dehumidification and thermal regeneration characterization of binary deep eutectic solvents in liquid desiccant air conditioning systems

The energy-saving propensity of liquid desiccant air dehumidification technique compared with its counterparts, mitigating the limitations of conventional desiccant solutions and the need for energy optimization in indoor space cooling, has invigorated the exploration of alternative desiccant solutions. This study investigates different binary deep eutectic solvents as a potential alternative working fluids in liquid desiccant air conditioning systems. Hydrogen bond acceptors (Choline chloride, N, N-Diethylethanolammonium chloride, 1-Butyl-3-methylimidazolium chloride, ZnCl2) and hydrogen bond donor (Ethylene glycol) were synthesized in different ratios to form binary deep eutectic solvents. The physiochemical, thermophysical and rheological properties of the investigated solutions were characterized and evaluated. DES A1 (mixture of choline chloride and ethylene glycol in ratio 1:2) and DES D1 (1-Butyl-3-methylimidazolium chloride and ethylene glycol in ratio 1:1) were found best among investigated binary DES solutions. The dehumidification and thermal regeneration potential of these promising solutions were further investigated in a humidity chamber and a drying oven, respectively. At 65 % relative humidity, 30 °C air temperature, and 3.77 × 10−4 m2 moisture-desiccant contact area, the estimated dehumidification mass flux of DES A1 and DES D1 are 4.61 × 10−2 and 3 × 10−2 g/m2∙s, respectively. Empirical correlations obtained for deep eutectic solvents moisture absorption in this study provide an error limit between ±2.6 % to ±3.5 %. These solutions are found promising as alternative solutions for dehumidification and thermal regeneration.

Novel Deep Eutectic Solvents Based on Pyrogallol: Synthesis and Characterizations

In this work, novel binary deep eutectic solvents (DESs) have been synthesized using pyrogallol (PY) as a hydrogen bond donor (HBD) and quaternary ammonium salts, choline chloride (ChCl), n-dodecyl...