Chloride-based Deep Eutectic Solvents Research Articles

Reducing Free Fatty Acids in Crude Palm Oil Using Diethylene Glycol and Zinc(II) Chloride Based Deep Eutectic Solvent

Deep eutectic solvents (DES) were prepared by precise combinations of mol fractions of chemical compounds, resulting in a lowered melting point due to hydrogen bonding. This research aimed to elucidate the physicochemical attributes of DES and its effectiveness in mitigating free fatty acid (FFA) levels in crude palm oil (CPO). Zinc(II) chloride (ZnCl2) served as the hydrogen bond acceptor (HBA) while diethylene glycol (DEG) as the hydrogen bond donor (HBD). Characterization included freezing point, density, viscosity, conductivity, and pH determination. At a ZnCl2 mol fraction of 0.30, the resulting DES exhibited homogeneity with transparent liquid properties, featuring a freezing point below −10 °C, density of 1.42 g/mL, viscosity of 1933.40 cP, conductivity of 66.13 µS/cm, and pH 3.42. FTIR spectra confirmed hydrogen bond interactions between HBA and HBD. Applied to CPO at a 1:1 volumetric ratio (DES:CPO), with 2 h of stirring time at 50 °C, FFA content decreased from 4.11 to 0.86%. This research highlights DES as an environmentally sustainable purification agent, significantly reducing FFA levels in unrefined palm oil.

Process design for acidic and alcohol based deep eutectic solvent pretreatment and high pressure homogenization of palm bunches for nanocellulose production

This research aimed to study on nanocellulose production from palm bunch using process design and cost analysis. Choline chloride based deep eutectic solvent pretreatment was selected for high-purity cellulose separation at mild condition, followed by nano-fibrillation using mechanical treatment. Three types of choline chloride-based deep eutectic solvents employing different hydrogen-bond donors (HBDs) namely lactic acid, 1,3-butanediol and oxalic acid were studied. The optimal cellulose extraction condition was choline chloride/lactic acid (ChLa80C) pretreatment of palm empty bunch at 80 °C followed by bleaching yielding 94.96%w/w cellulose content in product. Size reduction using ultrasonication and high-pressure homogenization produced nanocellulose at 67.12%w/w based on cellulose in raw material. Different morphologies of nanocellulose were tunable in the forms of nanocrystals, nano-rods and nanofibers by using dissimilar deep eutectic solvents. This work offered a sustainable and environmentally friendly process as well as provided analysis of DES pretreatment and overview operating cost for nanocellulose production. Application of nanocellulose for the fabrication of highly functional and biodegradable material for nanomedicine, electronic, optical, and micromechanical devices is achievable in the near future.

Role of Oxidants in Metal Extraction from Sulfide Minerals in a Deep Eutectic Solvent.

Metallurgical applications of deep eutectic solvents (DESs), known as ionometallurgy, have received significant research attention in recent years. While many studies claim that DESs are generally green and enhance process efficiency, others believe that industrial applications of ionometallurgy are generally not viable. Here, we report on leaching experiments of a sulfide flotation concentrate using ethaline, a chloride-based DES, in the presence of common oxidants. Following a mineral-based approach, we compare results with those obtained from aqueous chloride solutions to assess the influence of the leaching medium. We aim to contribute to a basic understanding of key differences between DESs and aqueous solutions and hope that this will help to make informed decisions about the suitability of DESs for leaching applications. Experiments were performed on a feed concentrate comprising a mixture of sulfide minerals along with substantial concentrations of Au, Ag, and Te. We found similar leaching behaviors for ethaline and aqueous solutions in nonoxidative leaching. However, when oxidizing agents were introduced, ethaline exhibited higher leaching efficiencies. Notably, the oxidation rate of pyrite in ethaline was very low, while chalcopyrite exhibited high oxidation rates. Furthermore, the results highlight significant variations in leaching rates depending on the type of oxidant, with the highest rate observed for I2, followed by CuCl2, and FeCl3. H2O2 and O2 were less effective. The leaching of gold-silver tellurides was possible in ethaline. This could be of particular significance, given that Au-Ag-Te compounds pose challenges in conventional cyanide treatment.

Influence of Electrolyte Choice on Zinc Electrodeposition.

Zinc electrodeposition serves as a crucial electrochemical process widely employed in various industries, particularly in automotive manufacturing, owing to its cost effectiveness compared to traditional methods. However, traditional zinc electrodeposition using aqueous solutions faces challenges related to toxicity and hydrogen gas generation. Non-aqueous electrolytes such as ionic liquids (ILs) and deep eutectic solvents (DESs) have gained attention, with choline-chloride-based DESs showing promise despite raising environmental concerns. In this study, zinc electrodeposition on mild steel was investigated using three distinct electrolytes: (i) halide-free aqueous solutions, (ii) chloride-based DES, and (iii) halide-free acetate-based organic solutions. The study examined the influence of deposition time on the growth of Zn on mild steel substrates from these electrolytes using physical characterization techniques, including scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results indicate that glycol + acetate-based non-aqueous organic solutions provide an eco-friendly alternative, exhibiting comparable efficiency, enhanced crystalline growth, and promising corrosion resistance. This research contributes valuable insights into the impact of electrolyte choice on zinc electrodeposition, offering a pathway towards more sustainable and efficient processes. Through a comprehensive comparison and analysis of these methods, it advances our understanding of the practical applications of zinc electrodeposition technology.

Unconventional Electrochemical Behaviors of Cu Underpotential Deposition in a Chloride-Based Deep Eutectic Solvent: High Underpotential Shift and Low Coverage.

The (5 × 5) Moiré pattern resulting from coadsorption of Cu atoms and chloride ions on the Au(111) electrode is one of the most classical structures for underpotential deposition (UPD) in electrochemical surface science. Although two models have been proposed to describe the pattern, the details of the structure remain ambiguous and controversial, leading to a question that remains to be answered. In this work, we investigate the UPD behaviors of Cu on the Au(111) electrode in a chloride-based deep eutectic solvent ethaline by in situ scanning tunneling microscopy (STM). Benefiting from the properties of the ultraconcentrated electrolyte, we directly image not only Cu but also Cl adlayers by finely tuning tunneling conditions. The structure is unambiguously determined for both Cu and Cl adlayers, where an incommensurate Cu layer is adsorbed on the Au(111) surface with a Cu coverage of 0.64, while the Cl coverage is 0.32 (only half of the expected value); i.e., the atomic arrangement of the observed (5 × 5) Moiré pattern in ethaline matches neither of the models proposed in the literature. Meanwhile, STM results confirm the origin of the cathodic peak in the cyclic voltammogram, which indicates that the underpotential shift of Cu UPD in ethaline indeed increases by ca. 0.40 V compared to its counterpart in a sulfuric acid solution, resulting in a significant deviation from the linear relation between the underpotential shift and the difference in work functions proposed in the literature. The unconventional electrochemical behaviors of Cu UPD reveal the specialty of both the bulk and the interface in the chloride-based deep eutectic solvent.

Antiamoebic properties of Methyltrioctylammonium chloride based deep eutectic solvents.

This aim of this study was to assess anti-parasitic properties of deep eutectic solvents against eye pathogen, Acanthamoeba, often associated with the use of contact lens. Assays were performed to investigate the effects of various Methyltrioctylammonium chloride-based deep eutectic solvents on Acanthamoeba castellanii, comprising amoebicidal assays, encystment assays, excystment assays, cytotoxicity assays by measuring lactate dehydrogenase release from human cells, and cytopathogenicity assays to determine parasite-mediated host cell death. In a 2h incubation period, DES-B, DES-C, DES-D, and DES-E exhibited up to 85% amoebicidal activity at micromolar doses, which was enhanced further following 24h incubation. When tested in encystment assays, selected deep eutectic solvents abolished cyst formation and were able to block excystment of A. castellanii. All solvents exhibited minimal human cell cytotoxicity except DES-D. Finally, all tested deep eutectic solvents inhibited amoeba-mediated cytopathogenicity, except DES-B. Deep eutectic solvents show potent antiamoebic effects. These findings are promising and could lead to the development of novel contact lens disinfectants, as well as opening several avenues to explore the molecular mechanisms, various doses and incubation periods, and use of different bases against Acanthamoeba castellanii.

Evaluation of canonical choline chloride based deep eutectic solvents as dye-sensitized solar cell electrolytes.

Deep eutectic solvents (DESs) are beginning to attract interest as electrolyte alternatives to conventional organic solvents and ionic liquids within dye-sensitized solar cells (DSSCs). The precise roles played by DES components and whether they simply represent a benign medium for mobilizing charge carriers or present beneficial functionality that impacts device performance remain unclear. To begin to address this deficiency in understanding, we performed a comprehensive characterization of the three "canonical" choline chloride-based DESs (i.e., reline, ethaline, and glyceline) as DSSC electrolytes hosting the iodide-triiodide (I-/I3 -) redox couple. The measurement of electrolyte viscosities, determination of triiodide diffusion coefficients, and photovoltaic performances assessed for water contents up to 40 wt. % allow the emergence of several important insights. A comparison to the observed photovoltaic performance arising from the individual components aids in further clarifying the impact of DES chemistry and solution viscosity on photovoltaic and charge carrier diffusion characteristics. Finally, we introduce the DES guaniline-consisting of a 1:1 molar ratio mixture of choline chloride with guanidinium thiocyanate-demonstrating it to be a superior DSSC electrolyte over those formulated from the three most widely studied canonical DESs at all water contents investigated.

Solubilization properties and structural characterization of dissociated HgO and HgCl2 in deep eutectic solvents

A synergic approach combining X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopies together with quantum mechanical (QM) calculations on cluster models has been used to investigate the solvation properties of the HgCl2 salt and of HgO dissolved in deep eutectic solvents (DESs). Choline chloride (ChCl)-based DESs were prepared using different hydrogen bond donors, namely 1:2 mixtures of ChCl and either urea, acetylsalicylic acid (ASA) or sesamol (SES) and a 1:1 mixture of ChCl and pyrogallol (PYR). The XANES results show that both HgCl2 and HgO molecules are completely dissociated in all the investigated DESs and the Hg2+ first coordination shell is composed only of Cl− anions in all the systems, with a local structure of Cl− ligands around the Hg2+ ion that is the same independently of the DES solvent and of the nature of the dissolved species. By applying a deconvolution procedure on the Hg L3-edge raw XANES experimental data and carrying out fitting procedures of the deconvolved XANES data using different coordination models for the Cl− anions surrounding Hg2+, we were able to unambigously determine the coordination number and the geometry of the Hg2+ first shell complex, namely a [HgCl4]2− tetrahedral coordination model. The analysis of the EXAFS spectra of HgCl2 salt in ChCl-Urea, ChCl-ASA, ChCl-SES and ChCl-PYR and of HgO dissolved in ChCl-ASA allowed us to obtain a very accurate determination of the HgCl first shell average distance (2.47–2.48 Å), in agreement with the XANES determinations. Moreover, ab initio calculations of different [HgCln](2−n)+ clusters carried out both in vacuum and simulating bulk solvent effects by means of the SMD solvation model strongly support the experimental findings that, in DESs, Hg2+ forms a complex with four chloride ions arranged in a tetrahedral geometry. The Cl− ion is thus shown to form such strong interactions with Hg2+ that none of the DES hydrogen bond donors is able to compete with it and act as a ligand for Hg2+. The strong solvation ability of the Cl− anions towards metal ions can be at the origin of the high solubility of metal oxides in chloride-based DESs, which is crucial in several important processes such as metal winning, corrosion remediation and catalyst preparation.

Hydrophobic deep eutectic solvent-based ultrasonic-assisted dispersive liquid-liquid microextraction for preconcentration and determination of trace cadmium and arsenic in wine samples

In present study, DL-lactic acid/trioctylmethylammonium chloride-based deep eutectic solvent (DES), which was considered as an environmental friendly extraction solvent to replace traditional organic reagent, was firstly presented for monitoring of trace cadmium (Cd) and arsenic (As) in wine samples by ultrasonic-assisted dispersive liquid-liquid microextraction (UA-DLLME) method. Moreover, different extraction conditions, including the type and volume of DES and dispersive solvent, pH of the solution, salt amount, time of vortex and sonication, were systematically evaluated. At the optimized extraction conditions, good linear relationships (0.50–8.0 μg·L−1 for Cd, 2.0–50 μg·L−1 for As) were obtained and limits of detection of Cd and As were 0.080 and 0.30 μg·L−1, respectively. In addition, the accuracy (as recoveries %), and intra-/inter-day precision (as relative standard deviation %) were in the ranges of 90.6–103.6% and 2.9–4.5%, respectively. Finally, the proposed method was applied to analyze 6 kinds of wine samples, which possessed wide practical application value in monitoring heavy metal residues in wine and even complex food matrices.

Straightforward and rapid Petasis multicomponent reactions in deep eutectic solvent

Deep eutectic solvents (DESs) have emerged as a promising, inexpensive, safe, renewable, and biodegradable alternative to harmful organic solvents as a premise for the green industrial transformation. An efficient and straightforward one-pot three-component Petasis reactions of salicylaldehyde derivatives with various amines and boronic acids in the glycerol/choline chloride-based deep eutectic solvent (DES) were developed. Wide varieties of Mannich-type products were obtained in acceptable to excellent yields under mild conditions and short reaction times. The exceptional features of this procedure involve facile and environmentally friendly solvent, recyclable reaction media, and wide tolerance toward functional groups. The DES system can be recycled four times without significantly decreasing the yields.

Preparation of 5-HMF in a DES/Ethyl N-Butyrate Two-Phase System

In this paper, a two-phase system, formed by oxalic acid/choline chloride-based deep eutectic solvent (DES) and chosen extractants, was used as a dissolution–reaction–separation system, and metal chloride was used as a catalyst to study the degradation of cellulose to produce 5-hydroxymethylfurfural (5-HMF) and glucose. The effects of the amount of organic solvent and the reaction temperature on product yield, the repeated recycling of DES, the comparison between a two-phase system and a homogeneous system, and the mechanism of cellulose degradation to 5-HMF were investigated. The results show that ethyl n-butyrate has the best extraction effect on 5-HMF. Compared with the homogeneous system, the yield of 5-HMF and glucose in the two-phase system is significantly improved. At a temperature of 140 °C and a reaction time of 120 min, the yields of glucose and 5-HMF reached the maximum, which were 23.5% and 29.8%, respectively. After DES was reused three times, the yields of glucose and 5-HMF decreased greatly, indicating that the recycling rate of DES was low.

A methanol–choline chloride based deep eutectic solvent enhances the catalytic oxidation of lignin into acetovanillone and acetic acid

A methanol/choline chloride-based deep eutectic solvent enhances the catalytic oxidation of lignin into acetovanillone and acetic acid under mild conditions.

Preparation of some zinc chloride based deep eutectic solvents and their characterization

In this investigation, the evaporating method was successfully employed for the preparations of three deep eutectic solvents (DES) based on zinc chloride with different HBDs such as glucose, fructose and lactic acid. These DESs were subjected to study their physical properties such as density, conductivity, viscosity and pH. The H bonded interactions of these DESs were analyzed using FTIR spectroscopy. Three zinc chloride-based DESs were successfully synthesized and reported in this study. Data obtained indicated that the all these DESs are existing as a clear liquid at room temperature and the findings showed that the newly formed DESs have the potential for the usage as solvents.

Electrodeposition of Ferromagnetic FeCo and FeCoMn Alloy from Choline Chloride Based Deep Eutectic Solvent

The electrodeposition of Fe, Co, FeCo, and FeCoMn alloy films has been performed from the choline chloride/urea deep eutectic solvent without additives. The effects of solution temperature, electrolyte concentration, deposition potential, and solution agitation on deposition rate have been studied. Film composition, morphology, crystallographic structure as well as the magnetic moment and coercivity were characterized and compared against the deposition conditions. A dominant mass transport effect was observed across most of the deposition cases. A manganese underpotential deposition phenomenon occurred with the alloy deposition. An elevated temperature results in significantly faster deposition and promotes smooth film growth with limited cracking. As-deposited FeCo alloy films are found to be ferromagnetic and nanocrystalline.

Pulse Plating of Copper from Deep Eutectic Solvents

The effect of pulse parameters on the deposition of copper from a chloride-based deep eutectic solvent (DES) was investigated. While satisfactory deposits could be obtained for some pulse conditions, at small duty cycles or long off-times the current efficiencies obtained were very low. These findings were consistent with a corrosion process occurring during the off-time, most likely the comproportionation reaction: Cu + CuIICl4 2- -> 2CuICl2 -. Initial experimental results were consistent with the corrosion rate being controlled by the transport of the CuIICl4 2- species to the electrode surface. With this assumption, a simple corrosion model was developed to account for the observed loss in current efficiency as a function of the pulse conditions. While this model broadly predicts the observed results some discrepancy between the observed and measured were noted.

Effects of concentration, salinity and injection scenario of ionic liquids analogue in heavy oil recovery enhancement

Abstract Recently, Deep Eutectic Solvents (DESs) have been demonstrated to be an effective analogue of ionic liquid in many applications. In our previous report, for the first time, two Chloride-based DESs were shown to have significant effects on different oil recovery mechanisms in heavy oil/formation brine/Berea sandstone system. In this report, the same DESs were used. The effects of DESs concentration, secondary and tertiary DES injections and brine salinity on recovery performance were examined through IFT measurements, contact angle measurements and core flooding experiments. Results of capillary number calculations indicated that although DESs solutions increased the IFT value, the capillary numbers in DESs flooding due to viscous forces and wettability alteration were higher than brine flooding case. Results showed that for both DESs, although the heavy oil recovery factors decreased by diluting the DES solution with brine from 50 vol% to 5 vol%, they were still promising between 6.3 and 8.7% for DES1 and DES2 respectively at lower concentrations of 5 vol%. Also, by reducing concentration from 50 to 25 vol%, there were no changes in recovery factors from 14 to 13.6% for DES1 and from 23.2 to 23.1% for DES2. The same trend was observed during wettability alteration study by contact angle measurements between oil droplet and aged surface of rock samples in the both DESs solutions at different concentrations. It verified that wettability alteration during DES injection has significant impact on oil recovery and it could be dominant and governing mechanism of heavy oil recovery enhancement. The DESs flooding in tertiary stage led to higher total recovery factors. The total recovery at tertiary mode compared to secondary mode were around 16% higher at 50 vol% concentrations and 3–6% higher at 5 vol% concentrations for both DESs. In addition, Results confirmed that the DESs can tolerate wide range of reservoir’s salinities and there were no big changes in oil recovery at different brine salinity during tertiary DESs injection.

ChemInform Abstract: Choline Chloride Based Deep Eutectic Solvent as an Efficient Solvent for the Benzylation of Phenols.

ChemInformVolume 46, Issue 18 Isocyclic Compounds ChemInform Abstract: Choline Chloride Based Deep Eutectic Solvent as an Efficient Solvent for the Benzylation of Phenols. Abhilash S. Singh, Abhilash S. Singh Dep. Chem., Inst. Chem. Technol. (Deemed), Matunga, Mumbai 400 019, IndiaSearch for more papers by this authorSuresh S. Shendage, Suresh S. Shendage Dep. Chem., Inst. Chem. Technol. (Deemed), Matunga, Mumbai 400 019, IndiaSearch for more papers by this authorJayashree M. Nagarkar, Jayashree M. Nagarkar Dep. Chem., Inst. Chem. Technol. (Deemed), Matunga, Mumbai 400 019, IndiaSearch for more papers by this author Abhilash S. Singh, Abhilash S. Singh Dep. Chem., Inst. Chem. Technol. (Deemed), Matunga, Mumbai 400 019, IndiaSearch for more papers by this authorSuresh S. Shendage, Suresh S. Shendage Dep. Chem., Inst. Chem. Technol. (Deemed), Matunga, Mumbai 400 019, IndiaSearch for more papers by this authorJayashree M. Nagarkar, Jayashree M. Nagarkar Dep. Chem., Inst. Chem. Technol. (Deemed), Matunga, Mumbai 400 019, IndiaSearch for more papers by this author First published: 16 April 2015 https://doi.org/10.1002/chin.201518085Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume46, Issue18May, 2015 RelatedInformation

Zinc (II) chloride-based deep eutectic solvents for application as electrolytes: Preparation and characterization

Deep eutectic solvents (DESs) have gained interest due to their favorable electrochemical properties. This work introduced a new group of zinc (II) chloride based DESs and characterized their melting temperatures, viscosities, electrical conductivities, refractive indices, as well as electrical window over a wide range of temperatures. The ammonium-based deep eutectic solvents possessed lower melting temperatures, lower viscosities and higher electrical conductivities in comparison to phosphonium-based ones. The deep eutectic solvent made from choline chloride and zinc (II) chloride at a mole ratio of 1:1 possessed high conductivities, 574–4779μS·cm−1, relatively low viscosities, 0.8278–0.2842Pa·s, and wide electrochemical window, 3.74V within the studied temperature range. The attained measurements were compared with other reported deep eutectic solvents in the literature.

Evaluation of toxicity and biodegradability of choline chloride based deep eutectic solvents

Deep eutectic solvents (DESs) have been dramatically expanding in popularity as a new generation of environmentally friendly solvents with possible applications in various industrial fields, but their ecological footprint has not yet been thoroughly investigated. In the present study, three choline chloride-based DESs with glucose, glycerol and oxalic acid as hydrogen bond donors were evaluated for in vitro toxicity using fish and human cell line, phytotoxicity using wheat and biodegradability using wastewater microorganisms through closed bottle test. Obtained in vitro toxicity data on cell lines indicate that choline chloride: glucose and choline chloride:glycerol possess low cytotoxicity (EC50>10mM for both cell lines) while choline chloride:oxalic acid possess moderate cytotoxicity (EC50 value 1.64mM and 4.19mM for fish and human cell line, respectively). Results on phytotoxicity imply that tested DESs are non-toxic with seed germination EC50 values higher than 5000mgl−1. All tested DESs were classified as′readily biodegradable′ based on their high levels of mineralization (68–96%). These findings indicate that DESs have a green profile and a good prospect for a wider use in the field of green technologies.