Deep Eutectic Research Articles

Exploring the Efficiency of Caprylic Acid and Quaternary Ammonium Salt-Based Deep Eutectic Solvents for Separation of CO2 and H2S from Gas Mixtures Using Molecular Dynamics Simulations and COSMO-RS

In the present study, quaternary ammonium salts (QAS) and caprylic acid based deep eutectic solvents (DES) were employed for the separation of CO2 and H2S from natural gas (NG). To understand the extraction mechanisms of H2S from NG, we utilized MD simulations to understand intermolecular interactions between the gases and the eutectic solvents. Our detailed analysis for better understanding of QAS absorption capability in H2S extractions included combined distribution functions (CDFs), which encompass radial distribution functions (RDFs), angular distribution functions (ADFs), hydrogen-bonding networks, density profiles, spatial distribution functions (SDFs), and the non-bond energies between H2S and the DES components, all measured at 310 K. Additionally, we calculated the solubility of H2S and CO2 gases as well as the solubility selectivity and diffusivity selectivity parameters to evaluate the performance of the QAS-based DES in sweetening processes of NG. The results represent that eutectic solvents based on quaternary ammonium chloride are effective for H2S adsorption and show selectivity for H2S in gas mixtures. Furthermore, the COSMO-RS model was used to predict the solubility of various gases (H2S/CO2) in the QAS-based DES, providing further insights into their effectiveness.

Salting-out Effects in Extraction of Phenol from Aqueous Solutions Using a Hydrophobic Deep Eutectic Solvent Based on Dodecanoic and Octanoic Acids: Experimental Study and Comparison

Salting-out Effects in Extraction of Phenol from Aqueous Solutions Using a Hydrophobic Deep Eutectic Solvent Based on Dodecanoic and Octanoic Acids: Experimental Study and Comparison

In-Syringe Vortex-Assisted Liquid-Liquid Microextraction Based on Natural Deep Eutectic Solvent for Simultaneous Determination of the Two Anticancer Polyphenols Chrysin and Resveratrol.

The simultaneous determination of multiple anticancer drugs in combination therapy poses a significant analytical challenge due to their complex nature and low concentrations. In this study, we propose an in-syringe vortex-assisted liquid-liquid microextraction (IS-VA-LLME), based on a green natural deep eutectic solvent (NaDES) for the simultaneous determination of two coadministered anticancer drugs (resveratrol and chrysin) prior to the HPLC-UV analysis, for the first time. The key parameters affecting the extraction efficiency, such as extraction solvent, vortex time, pH, and ionic strength were optimized. Under optimal conditions, the method demonstrates good linearity over the range of 0.05-15.0 μg/mL for RVT and 0.50-15.0 μg/mL for CHR with low limits of detection (LODs) of 16.78 and 161.60 ng/mL for RVT and CHR, respectively, confirming the high sensitivity of the method. The interday and intraday precision values, expressed as %RSDs, are below 2.0%, indicating good repeatability and reproducibility. Furthermore, the proposed method could be efficiently applied for the determination of the two drugs in human plasma and river water. The obtained results show satisfactory % recoveries (97.80%-102.04%), highlighting the accuracy and reliability of the developed method. The sustainability of the method was comprehensively evaluated using seven different tools. In conclusion, the developed IS-VA-LLME-NaDES allows for enhanced extraction efficiency, reduced extraction time, and improved recovery of the target analytes. This method holds great promise for applications in clinical and environmental research, enabling the precise quantification of these anticancer drugs in complex matrices.

Unravelling The Bioactivities of Acmella paniculata Extract-Mediated Green Deep Eutectic Solvent of Citric Acid Monohydrate and Glycerol

Plants are important sources of underlying medicinal value properties. The extraction of bioactive compounds from botanical sources using green solvents has gained interest due to its environmental sustainability. This study highlighted the bioactivities potential of Acmella paniculata extract mediated by green deep eutectic solvent (DES) composed of the citric acid monohydrate and glycerol. Acmella paniculata, a local flowering shrub was selected due to its rich medicinal value compounds. The synergistic effect between plant’s bioactive compounds and DES is capable of enhancing bioactivity, making DES a promising plant solvent extractor candidate. The plant extracts were prepared in leaf and flower parts using the centrifugation method. The phytochemical screening for both extracts showed the presence of terpenoids and steroid constituents which have valuable bioactivity functions. The antibacterial activity assessed by disc diffusion assay exhibited higher susceptible bacterial response of E. coli, Salmonella enterica ser. Typhimurium and S. aureus against the flower extract compared to the leaf extract. The DPPH assay was conducted to assess free radical scavenging activity. The flower extract demonstrated radical scavenging activity (RSA) of 75%-77% while the leaf extract demonstrated 65%-69%. The flower extract results showed higher RSA emphasizing its potential as a natural antioxidant. The anti-inflammatory activity was determined by egg albumin denaturation assay, which showed a greater inhibition rate in flower extract than the leaf extract which was up to 95% and 89% respectively. Thus, both extracts possess an in vitro anti-inflammatory effect. Conclusively, flower extract exhibited better bioactivities value than leaf extract in a green DES. Hence, offering a new insight into its application as an effective alternative in natural product-based therapeutics.

Total Utilization of Components Contained in Coconut Husk by Microwave-Assisted Thermal Hydrolysis and Deep Eutectic Solvent Treatment

Total Utilization of Components Contained in Coconut Husk by Microwave-Assisted Thermal Hydrolysis and Deep Eutectic Solvent Treatment

Rapid and Environmentally-Friendly Synthesis of Thiazolidinone Analogues in Deep Eutectic Solvent Complemented with Computational Studies.

A greener, safer, and more efficient methodology for the synthesis of (Z)-5-benzylidene-2-thioxothiazolidin-4-ones (3 a-u) and (Z)-5-benzylidenethiazolidine-2,4-diones (4 a-i) has been developed. The deep eutectic solvent (DES) ZnCl2/urea used as a greener solvent as well as a catalyst in this study accelerated the condensation of rhodanine and thiazolidine-2,4-dione with different aldehydes to afford the target scaffolds in excellent yields (88-98 %). The reaction methodology adopted offered significant advantages such as mild reaction conditions, functional group tolerance, quick reaction time, column-free isolation, catalytic recyclability, and applicability to gram-scale production. Moreover, density function theory calculations were carried out to investigate the global reactivity and stability profiles of these compounds. Finally, the green metrics analysis supported the greener nature of the present methodology.

Comparison of the Effects of NaOH and Deep Eutectic Solvent Catalyzed Tobacco Stock Lignin Isolation: Chemical Structure and Thermal Characteristics

Uncovering the structure of lignin from biorefinery has an important effect on lignin catalytic depolymerization and the production of bioenergy. In this study, two biorefinery lignins were isolated from tobacco stalks via alkaline and deep eutectic solvent (DES) catalyzed delignification processes, and the lignin heterogeneity structural characteristics were elucidated by gel permeation chromatography, 2D-HSQC, FT-IR, etc., to understand the relationship between the structure and the thermal characteristics of lignin. It was found that the lignins presented various structural characteristics and components, in which the predominant interunit linkages of black liquor lignin are β-O-4 and β-β linkages, and the β-O-4 linkages disappeared by DES treatment. DES lignins exhibited lower molecular weights and yields than black liquor lignin. Thermogravimetric analysis and fixed-bed pyrolysis were also performed to investigate the lignin thermal behavior. The results show that the DES approach can improve the bio-oil production from lignin and highlight the potential of DES lignin as a promising feedstock in the lignin pyrolysis process. This work provides a valuable example of the conversion of biorefinery lignin into pyrolysis products.

Optimization of White Tea Flavanol Extraction Process by the Ultrasonic‐Assisted Deep Eutectic Solvent Method and Determination of the Antioxidant and Antibacterial Activity

ABSTRACTFlavanols have a variety of health benefits and biological activities and become the hotspot of the food development and research. In this research, flavanols were extracted from white tea by ultrasonic‐assisted deep eutectic solvent (DES) method. High‐performance liquid chromatography was used to determine the content of flavanols. The influence of four factors on the flavanol extraction yield was analyzed by single factor experiments, including deep eutectic solvent mole ratio (the mole of hydrogen bond acceptors: the mole of hydrogen bond donors), solid–liquid ratio (white tea sample weight/g: the volume of DES/mL), extraction time and extraction temperature. On the basis of single factor experiments, the factors which had significant effects on the flavanol extraction yield were further optimized by the response surface test. The results showed that the optimized extraction conditions were as follows: the mole ratio of DES 1: 4 (choline chloride: 1,2‐propanediol), the solid–liquid ratio 1:30, the extraction temperature 56°C, the extraction time 53 min, and the ultrasonic power 341 W. Under the above parameters, the extraction yield of white tea flavanols was 9.63 mg/g. After purification with macroporous resin, antioxidation and antibacterial experiments were carried out. The results showed that the antioxidant and antibacterial effects of white tea flavanols were remarkable. The antibacterial effects performed best on Escherichia coli, followed by Bacillus subtilis and Staphylococcus aureus. The maximum diameter of the antibacterial zone on Escherichia coli was 0.95 ± 0.11 mm. The best radical scavenging rates of OH, ABTS+ and DPPH were 97.1%, 97.5%, and 88.4%, respectively, when the flavanol concentration was 9.5 mg/mL. The conclusions of this research can provide theoretical foundation for the further study of white tea flavanols.

Silica‐Mediated Incorporation of Lipase Into The Bulk of a Deep Eutectic Solvent: An Efficient Biocatalytic Phase for Esters Synthesis

Aiming at sustainable solutions suitable for industrial‐scale catalysis catalytic phase containing lipase and Deep Eutectic Solvent (DES) was designed. To achieve this, both physical and chemical immobilizations of lipases were performed on the surface of silica and carbon materials. The catalytic activity of developed biosystem was tested in biotransformation of α‐angelica lactone into butyl levulinate at 60°C. The best results were achieved for Candida antarctica lipase B adsorbed on fumed silica suspended in choline chloride: glycerol (1:2) with the addition of 20 wt% of water. Under these conditions 99.9% conversion of α‐angelica lactone and 100% selectivity to butyl levulinate were obtained after 45 min. The biocatalytic system maintained its activity for up to five consecutive reaction cycles with full conversion of lactone to ester. The heterogenization of the enzyme allowed the biocatalyst to be integrated into the bulk of the DES, which includes essential water. This combination resulted in the formation of a stable and easy‐to‐operate catalytic phase where reagents formed a second organic phase. The integration of cost‐effective biocatalyst with process efficiency provides a greener alternative with significant potential for industrial use.

OPTIMIZATION ULTRASOUND-ASSISTED EXTRACTION USING CHOLINE CHLORIDE-BASED NATURAL DEEP EUTECTIC SOLVENT TO INCREASE PHENOLIC COMPOUNDS AND ANTIOXIDANTS FROM RHODOMYRTUS TOMENTOSA LEAVES

Objective: The main purpose of this study is to give recommendations for the ideal extraction conditions for improving the extraction yield and antioxidant activity of R. tomentosa leaves. Methods: First, the extraction total phenolic yields of five choline chloride-based Natural Deep Eutectic Solvents (NADES) were evaluated. Then, Box Behnken designs of Response Surface Methodology (RSM) were conducted in order to optimize the extraction condition. The extraction variables investigated were extraction time, water content in NADES, and solid-to-liquid ratio. Meanwhile, total phenolic and 2,2′-azinbis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) free radicals scavenging activity were used as responses. Results: NADES with combination of choline chloride and propylene glycol with a molar ratio of 1:1 was found to be the best solvent for extracting phenolic compound. The total phenolic compound obtained was 29.6351 mg GAE/g dried leaves with ABTS scavenging activity about 96.84% under the optimum extraction condition (extraction time of 60 min, 25% water content in NADES, and solid-to-liquid ratio of 0.02 g/ml). Better results were shown compared to extracts with conventional solvents. Conclusion: In sum, the use of choline chloride-based NADES as extraction solvent under optimum condition was proven to be effective in increasing the extraction efficiency of phenolic compounds and antioxidant activity from R. tomentosa leaves.

Enhanced Chemical Stability of Tetramethylammonium Head Groups via Deep Eutectic Solvent: A Computational Study.

The chemical stability of tetramethylammonium (TMA) head groups, both with and without the presence of a choline chloride and ethylene glycol-based deep eutectic solvent (DES), was studied using Density Functional Theory (DFT) calculations and ab initio Molecular Dynamics (MD) simulations. DFT calculations of transition state energetics (ΔEreaction, ΔGreaction, ΔEactivation, and ΔGactivation) for key degradation mechanisms, ylide formation (YF) and nucleophilic substitution (SN2), suggested that the presence of DES enhances the stability of the TMA head groups compared to systems without DES. Ab initio MD simulations across hydration levels (HLs) 1 to 5 indicated that without DES, YF dominates at lower HLs, while SN2 does not occur. In contrast, both mechanisms are suppressed in the presence of DES. Temperature also plays a role: without DES, YF dominates at 298 K, while SN2 becomes prominent at 320 K and 350 K. With DES, both degradation mechanisms are inhibited. These findings suggest DES could improve the chemical stability of TMA head groups in anion exchange membranes.

A Low-cost and Green Zinc-Iron Battery Achieved by Ethaline Deep Eutectic Solvent.

Deep eutectic solvents (DESs) were considered as a potential electrolyte because of their low price, harmless to environment and wider electrochemical window potential compared to water. In this work, Fe(Ⅲ)/Fe(Ⅱ) and Zn(Ⅱ)/Zn redox couples were used as the positive and negative active materials, respectively, in a DES system using choline chloride and ethylene glycol in a molar ratio of 1:2 (ethaline). The possible working mechanism of the battery was studied by cyclic voltammetry, spectroscopic and simulation methods. The effects of different temperatures, concentrations of zinc ions in the anolyte and current densities on battery performance were evaluated. The results showed that the designed zinc-iron battery should preferably be operated at a current density of 0.5 mA cm-2 and the temperature of 313~323 K, which will improve the energy efficiency and maintain a high coulombic efficiency. The variation of cycle performance test presents a different pattern from the usual batteries, which is due to the effect of RO- group. At 313 K and 0.5 mA cm-2, the coulombic efficiency increases from 14.1% to 100.2% after 46 cycles, and then remains at about 100% during the rest 54 cycles, which demonstrates a good cycle stability of DES-based zinc-iron battery.

The versatility of iota-carrageenan biopolymer for the fabrication of non-toxic bio-based energy storage devices

The number of portable devices produced worldwide is strongly increasing, which results in an increasing need for energy storage devices. These devices are typically fabricated with scarce and toxic materials. Consequently, there is a current trend towards the substitution of these materials by biopolymers, although they are still often mixed with toxic substances to improve specific performance aspects. To address this issue, this work presents a self-standing non-toxic and potentially biodegradable polymer electrolyte membrane for electrochemical energy storage applications consisting of an abundant biopolymer, iota-carrageenan, and Deep Eutectic Solvent (DES).11List of abbreviations: DES: Deep eutectic solvent [EMIM][SCN]: 1-Ethyl-3-methyl-imidazolium thiocyanate CV: Cyclic voltammetry FTIR: Fourier transformed infrared spectroscopy EIS: Electrochemical impedance spectroscopy CPE: Constant phase element. Ionic conductivities as high as 2 mS/cm were achieved for a proportion of carrageenan and DES of 25:75. Aqueous electrically conductive inks containing carbon black and active carbon were also developed using the same polymeric matrix. The inks were successfully printed (stencil method) on different substrates and electrically characterized, achieving sheet resistances as low as 38 Ω/sq. Supercapacitors were then fabricated by printing the electrically conductive ink on both sides of the self-standing membrane, demonstrating the versatility of iota-carrageenan biopolymer in the development of sustainable energy storage devices. The measured capacitance of the supercapacitors was 3.3 mF/cm2 in cyclic voltammetry characterization and 2.7 mF/cm2 when charging-discharging at 0.05 mA/cm2. The supercapacitors were found to be stable in cyclability studies, showing a capacity retention of 99 % after 5000 charge–discharge cycles.

Response Surface Methodology (RSM) Design to Optimize the Cathode of Li-Ions Batteries Recycling in Deep Eutectic Solvent and DFT Simulation

Response Surface Methodology (RSM) Design to Optimize the Cathode of Li-Ions Batteries Recycling in Deep Eutectic Solvent and DFT Simulation

Comparing Leaching Efficiency of Novel Deep Eutectic Solvent with Mineral Acids: Spodumene Ore

Comparing Leaching Efficiency of Novel Deep Eutectic Solvent with Mineral Acids: Spodumene Ore

Sustainable Extraction Strategy for Lignin from Coconut Coir Using Organosolv and Deep Eutectic Solvents (DES)

Sustainable Extraction Strategy for Lignin from Coconut Coir Using Organosolv and Deep Eutectic Solvents (DES)

Selective Leaching of Cadmium from Cold Filter Cake Using Green Deep Eutectic Solvent Choline Chloride-Oxalic Acid

Selective Leaching of Cadmium from Cold Filter Cake Using Green Deep Eutectic Solvent Choline Chloride-Oxalic Acid

Unveiling the high-pressure behavior of thymol+carvone NADES: A combined experimental-computational approach

this study considers the high-pressure behavior of thymol + carvone Natural Deep Eutectic Solvent using a combined experimental and computational approach. Experimentally, PVT (pressure – volume/density - temperature) measurements were conducted to characterize the fluid volumetric behavior as well as compressibility and internal pressure, which are directly related with hydrogen bonding and nanoscopic structuring. Likewise, these measurements provide crucial insights into the thermodynamic properties of the considered fluid under high pressure, which is pivotal for scaling up and process design for high pressure operations. Computationally, the PC-SAFT equation of state was employed to predict phase equilibria and PVT behavior, Machine Learning for density predictions, while Density Functional Theory and Classical Molecular Dynamics simulations were considered for the structural and dynamic characterization. These simulations provides insights into the electronic structure, intermolecular interactions (hydrogen bonding), liquid structuring and they unveil the pressure's impact on microscopic interactions, structural organization, and transport properties. This comprehensive investigation aims to shed light on the behavior under high pressure, facilitating their optimization for applications in chemical processing, energy storage, and materials science.

Spatially Confined Engineering Toward Deep Eutectic Electrolyte in Metal-Organic Framework Enabling Solid-State Zinc-Ion Batteries.

Uncontrollable interfacial side reactions generated from common aqueous electrolytes, just like the hydrogen evolution reaction (HER) and dendrite growth, have severely prevented the practical application of zinc-ion batteries (ZIBs). Solid-state ZIBs are considered to be an efficient strategy by adopting high-quality solid-state electrolytes (SSEs). Here, by confining deep eutectic electrolyte (DEE) into the nanochannels of metal-organic framework (MOF)-PCN-222, a stable DEE@PCN-222 SSE with internal Zn2+ transport channels was obtained. A distinctive ion-transport network composed of DEE and PCN-222 in the interior of DEE@PCN-222 realizes the efficient Zn2+ conduction, contributing to high ionic conductivity of 3.13×10-4 S cm-1 at room temperature, low activation energy of 0.12 eV, and a high Zn2+ transference number of 0.74. Furthermore, experimental and theoretical investigations demonstrate that DEE@PCN-222 with its unique channel structure could homogeneously regulate the Zn2+ distribution and effectively alleviate the side reactions. Highly reversible Zn plating/stripping performance of 2476 h can be realized by the SSE. The solid-state ZIBs show a specific capacity of 306 mAh g-1 and display cycling stability of 517 cycles. This unique design concept provides a new perspective in realizing the high-safety and high-performance ZIBs.

Investigation of Cellulose Nanocrystals Fabricated via Sulfuric Acid Combined with Deep Eutectic Solvent Route

To make full use of waste tobacco in cigarette production and enhance resource utilization efficiency, cellulose nanocrystals (CNCs) were prepared by a method of sulfuric acid combined with a deep eutectic solvent. This method was compared with conventional methods, and the CNCs were thoroughly characterized. The results indicated that the yield of CNCs prepared by the sulfuric acid combined with a deep eutectic solvent method exceeded 26%, with the highest yield reaching 29.5%, surpassing the yields from two other methods of 12.5%, 17.2%, corresponding to sulfuric acid and sulfuric acid-oxalic acid, respectively. Scanning electron microscopy revealed a laminar morphology of CNCs, in which the CNCs maintained a cellulose type I structure with well-preserved crystallinity. In addition, CNCs prepared by the sulfuric acid combined with a deep eutectic solvent method exhibited good thermal stability, with maximum mass loss at temperature of 342.8°C during third pyrolysis stage, higher than that of sulfuric acid at 316.7°C and sulfuric acid-oxalic acid at 335.9°C. Steady-state rheological testing revealed that the viscosity of the CNCs suspension decreased with an increasing shear rate, which is characteristic of pseudoplastic fluid shear thinning behavior. CNCs prepared by the sulfuric acid combined with DES method reduced the amount of sulfuric acid, and the yield was much higher than that of the other two methods. Moreover, the method using sulfuric acid combined with DES method was simple and safe, and the obtained CNCs had high thermal stability and viscosity, which expands the application prospects in biocomposite material fields.