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[Display omitted] • Novel THEDES with capric acid and ketoconazole. • Reduced MIC against Candida albicans. • 6.19-fold increase in skin drug permeation. • Hydrogen bonding confirmed via NMR and FT-IR. • Sustainable and eco-friendly drug delivery. In this study, we reported the investigation of a novel therapeutic deep eutectic system (THEDES) formed between capric acid (CA) and ketoconazole (KCZ) to enhance the permeability and efficacy of the antifungal drug KCZ. A THEDES was formulated by combining KCZ and CA at different molar ratios, with a 1:5 ratio (K5) representing the most stable and lowest melting point. Characterization of the interactions between CA and KCZ using NMR and FT-IR spectroscopy revealed a hydrogen bonding interaction between the amine group of KCZ's imidazole ring and the carboxylic acid moiety of CA. This interaction resulted in converting the solid materials into liquid at room temperature, leading to a significant decrease in the melting points of the components, as confirmed by DSC. Next, the effectiveness of K5 as an antifungal agent against Candida albicans was evaluated. The results indicated a 2-fold reduction in the minimum inhibitory concentration (MIC). In addition, permeability studies conducted using a Franz diffusion cell revealed a significant enhancement in permeability with a 6.19-fold increase in flux compared to commercially available KCZ cream. The findings suggest that fatty acid-based deep eutectic systems, such as the KCZ THEDES, can serve as effective and green drug delivery systems, offering significant enhancements in drug permeability and therapeutic performance. This approach improves the efficacy of drugs and promotes the development of eco-friendly pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pseudo-gemini surfactants were synthesized from commercially available reagents. • Material-efficient and energy-efficient reaction pathway was selected. • Adsorption, micellization and antimicrobial properties were evaluated. • Molecular simulation was performed using Dissipative Particle Dynamics. • Theoretical CMC values were in good agreement with experimental values. In this work new pseudo-gemini type surfactants are constructed via a simple, energy and material efficient way, using piperazine, propylene oxide and seven different fatty acids: capric, lauric, myristic, stearic, oleic and linolenic. The compounds are characterized by 1H NMR, 13C NMR and FTIR studies. Micellization and adsorption properties of the novel pseudo-gemini surfactants are investigated via surface tension and conductivity measurements. Antimicrobial properties are evaluated using the simple disk diffusion test method. Dissipative Particle Dynamics (DPD) simulations are performed to model aggregation behavior of the new pseudo-gemini surfactants. Experimental studies revealed that Critical Micelle Concentration (CMC) of the obtained pseudo-gemini surfactants are lower than 1 mmol/L. Theoretically calculated CMC values are slightly higher than experimental CMC values. However, overall, very good agreement between theoretical and experimental CMC values is observed. Radial Distribution Function (RDF) and radius of gyration (R g) plots are analyzed to gain further insight into aggregation of the surfactant molecules in aqueous environment. The DPD model of the pseudo-gemini amphiphiles successfully predicts the most important traits of the aggregation process. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrophobic TOPO-Decanoic acid DES has been synthesized. • Structural insights using DFT has been performed. • Physico-chemical properties of DES diluted with chloroform were determined. • DES diluted with chloroform used for extraction of Y and Eu. Deep eutectic solvents (DESs) are recently regarded as evolving candidates in the field of separation science in order to achieve sustainability. In the present work, hydrophobic TOPO-Decanoic acid DES has been synthesized and scrutinized by FTIR and 1HNMR studies. The structures of TOPO (Tri-octyl phosphine oxide), decanoic acid, chloroform, DES and DES + chloroform have been optimized employing B3LYP functional using DFT-D3 of Grimme's method. The HOMO-LUMO (E g) energy gap, bond lengths, mulliken charges,dipole moment and interaction energy has been evaluated using DFT. The geometry optimization provides the bond parameters which explain about the existence of non-bonded interactions. DES and DES + chloroform show more reactiveness as compared to its constituents evident from the chemical potential value. Physico-chemical properties such as density, volumetric (V), dielectric constant (ε), refractive index (n D) and ultrasonic velocity (U) of the hydrophobic TOPO-Decanoic acid DES diluted with polar cosolvent chloroform have been determined over a wide range of mole fraction of DES at 298.15 K. The excess properties such as VE, εE, n D E and UE have been calculated to predict the type of inter-molecular interaction existing within the components of the DES diluted chloroform mixture. Different mixing rules have been used to estimate properties such as dielectric permittivity, refractive index and ultrasonic velocity. Various acoustic parameters such as Z, β s , and (L f) mix of binary mixtures are evaluated to predict about the presence of inter molecular interactions within the mixture components. The prepared hydrophobic eutectic mixture in chloroform has been further used for extraction of Y (III) and Eu (III). The solvent extraction of Eu (III) showed better performance as compared to that of Y (III). [ABSTRACT FROM AUTHOR]

• Seven TBAC-DEC/OC-based DES were prepared with molar ratio from 1:3 to 3:1. • Two eutectics were determined through their solid–liquid diagrams. • HBD affected the properties of DES, including phase behavior and thermal stability. • The mass-connectivity-index-based model was introduced for density prediction. Deep eutectic solvent (DES) is considered as one of the green solvents with bright prospect in this century. Its excellent performance is closely related to the hydrogen bonds formed between hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD). Through changing the type of HBD and adjusting its molar fraction, it makes a difference to the intensity of the hydrogen bonds. In this work, tetrabutylammonium chloride (TBAC) was chosen as HBA, decanoic acid (DEC) and octanoic acid (OC) were chosen as HBD. With the molar ratios ranging from 3:1 to 1:3, seven TBAC-DEC-based DES and seven TBAC-OC-based DES were synthesized. Based on the study of the structural characteristics and the thermophysical properties, such as the eutectic point, the thermal stability, the density and the viscosity, the effect of HBD on DES was investigated. The increased HBD destroyed the orderly configuration of DES. Meanwhile, the elongation of the HBD's alkyl chain enhanced the interaction between the components. Moreover, the mass-connectivity-based model and the hard sphere model were introduced to predict the density and viscosity, respectively. Both of the two models exhibited good predictivity, with the average absolute relative deviation less than 0.2 % and 5 %, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Acid molecules in the oil phase can act like surfactants and form micelles. • Ions can disturb water-acid and improve acid-surfactant interaction. • Enhanced acid-surfactant interaction keeps acid molecules near the interface. • Ions and acid molecules synergize to orient surfactants parallel to the interface. Low salinity water injection with surfactants is one of the standard approaches in enhanced oil recovery (EOR). This method relies on the interaction of surfactants and ions at oil/water interfaces to reduce the interfacial tensions. However, the details of the mechanisms governing the synergistic effects of these components are still debatable. In this study, molecular dynamic (MD) simulations have been employed to investigate the challenging interactions of chemicals and saline water at a molecular scale. The model oil phase used in this study was defined as a mixture of toluene and decane. In addition, the synergistic materials are NaCl, sodium dodecyl ethoxy sulfate (AES), and decanoic acid. The results of density profiles, planar distribution maps, and PMF calculations imply that the acid molecules in the oil phase act as surfactants and form micelles. A few water molecules are also transferred to the oil phase to form water-acid micelles at high surfactant concentrations. Consequently, the number of acid components in the interfacial area is decreased; hence, the IFT reduction is alleviated. The results showed that micelle formation was decreased by adding ions to the aqueous phase. RDF profiles indicate that surfactant-acid interaction improves by adding ions to the water phase. The higher surfactant-acid interactions keep the polar hydrocarbon molecules near the interface and prevent them from moving to the hydrocarbon phase. This study also highlights the vital role of surfactant-acid interactions in the arrangements and orientations of surface-active materials. Orientation analysis indicates that salts in water and hydrophobic acids synergize to orient surfactants parallel to the interface. These facts signify that the surfactant-acid interaction is one of the main factors that critically affect the water–oil interfacial behavior. [ABSTRACT FROM AUTHOR]

[Display omitted] • Efficient phase transfer catalyst-assisted alkaline hydrolysis procedure of parabens was introduced. • Applying decanoic acid as the parent compound to ameliorate the prepared DES greener. • Tributyl phosphate-decanoic acid hydrophobic deep eutectic solvent has been prepared and used for the first time. • The combination of tributyl phosphate and decanoic acid promoted the extraction efficiency and chromatographic behavior. Deep eutectic solvents (DESs) are new alternative solvents used in sample preparation for dissolution, extraction and preconcentration of analytes. In this work, a tributyl phosphate (TBP)-based hydrophobic deep eutectic solvent was applied in the liquid–liquid microextraction (LLME) of total parabens in beverages. The sample preparation procedure consisted of two main steps: the phase transfer catalyst-assisted alkaline hydrolysis of parabens and the LLME of parabens' hydrolysate p-hydroxybenzoic acid (PHBA). The hydrolysis procedure was improved efficiently by the addition of phase transfer catalyst and the extractant became greener as the natural lauric acid (LauA) was used as the component of the DES. It was verified that the DES composed of TBP and LauA (3:1, mol/mol) was the most effective option for PHBA extraction. Response surface methodology (RSM) based on Box-Behnken design (BBD) was adopted to optimize the predominant experimental conditions. The proposed method provided satisfactory linearity (R2 ≥ 0.9991), detection limits (0.02 μmol/L), precisions (RSDs ≤ 4.5%), recoveries (85.2% to 104.6%) and negligible matrix effects, which offered a promising way for screening total parabens in various beverage samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mixtures of benzocainium ibuprofenate in menthol:decanoic acid with molar ratios of 1:2, 1:1 and 2:1 were prepared. • More pronounced solvation ability of system with an excess of decanoic acid (Men:DecA/1:2) than the other systems. • System with excess decanoic acid leaves the possibility that its excess makes interactions with the ionic liquid. • The presence of benzocainium ibuprofenate increases structural organization in all three NADES systems. In this work, the mixture of the active pharmaceutical ingredient ionic liquid (API-IL) benzocainium ibuprofenate and natural deep eutectic solvents (NADESs) of menthol:decanoic acid with the molar ratios 1:2, 1:1 and 2:1 were prepared, and nature of interactions in these systems was investigated for the first time. These systems of hydrophobic API-IL-NADES are mixtures that are compatible and offer an opportunity for the topical application of ionic liquids, which are in a liquid state above room temperature and do not dissolve in water well. Ionic liquid and NADESs with different molar ratios were synthesized and characterized using infrared and nuclear magnetic resonance spectroscopy and differential scanning calorimetry. The densities, speeds of sound, and viscosities of the studied mixtures were measured in the temperature range from T = (293.15 to 318.15) K at different API-IL molalities. From obtained thermodynamic properties, it was discussed how the mole fraction of the NADES components influences the molecular and solvent performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrophobic natural Deep Eutectic Solvents suitable for toluene extraction. • Effective intermolecular interactions between the aromatic and the hydrophobic moieties. • Minor solvent disruption upon toluene solubilization. • Toluene clustering for large aromatic content. • Solvent toxicity considered through lipid bilayer models showing adsorption for used solvent content. The hydrophobic deep eutectic solvent formed by the equimolar combination of natural compounds cineole and decanoic acid is studied as an archetypical compound for aromatics (toluene) solubilization/extraction purposes. The physicochemical properties of toluene solutions in the solvents are studied as a function of composition and temperature. The nature of intermolecular forces between toluene and solvent molecules is analyzed using a minimal clusters approach through quantum chemistry methods. Classical molecular dynamics simulation on toluene solution allowed us to infer nanoscopic behavior and structuring of the toluene mixtures using static and dynamic approaches. Likewise, the possible biological effects of the considered solvent are studied considering its effect on lipid bilayers as a model of plasma membranes using coarse-grained molecular dynamics methods. The reported results provide a multiscale combined experimental and computational characterization of hydrophobic Deep Eutectics as suitable solvents for aromatic hydrocarbons. [ABSTRACT FROM AUTHOR]

[Display omitted] • Enoxacin is extracted from an aqueous system using hydrophobic deep eutectic solvents (DESs). • Higher than 82% extraction efficiency is achieved through a single stage batch-type separation. • The influence of initial drug concentration, mass ratio of phases and stirring conditions on the extraction performance are investigated. • Higher than 90% extraction is achieved by the recycle process where DES is regenerated. • The computational analysis suggests multiple interactions between the drug and the DES. The current work addresses the extraction of a drug (enoxacin) from an aqueous environment by liquid-liquid extraction using three hydrophobic deep eutectic solvents (DES) namely, (a) dl -menthol: decanoic acid (1:1), (b) dl -menthol: dodecanoic acid (2:1), and (c) dodecanoic acid: decanoic acid (1:2). The experiments were conducted at varying mass ratios of DES/ water phase at ambient condition followed by quantum chemical (QC) analysis. Within the batch process with a single cycle, the extraction efficiency and the distribution ratio of 82 % and 4.75 respectively, were reported with the DES; dl -menthol: decanoic acid (1:1). Different initial drug concentrations (5 to 20 ppm) were introduced to observe the extraction performance at various contamination levels. Followed by the batch-type extraction experiments, three different recycling schemes have been implemented to assess the reuse and recovery of DESs. A 90 % percentage extraction was achieved by recycling the DES phase with purification through activated carbon (AC) which allowed it to maintain its continuity of the aqueous phase. The higher hydrophobicity of the DES phase with relatively high drug solubility proved to be the driving force of the enhanced DES-drug interaction. This was supported by the QC analysis as comparably higher non-bonded interaction energy was obtained for the DES-enoxacin complex suggesting stronger interaction and compactness. The charge transfer (CT) process confirmed the magnitude of charge transfer between DES and the drug through natural bonding orbital (NBO) charge analysis. Non-bonded interactions with dispersion effect were confirmed by the structural arrangement analysis of the complex supported by frontier molecular orbital (FMO) analysis. The quantum theory of atom in molecules and the non covalent interaction (QTAIM & NCI) analysis suggest hydrogen bonding and dispersion interactions (van der Waals) as the basis of interaction between the molecular groups. [ABSTRACT FROM AUTHOR]

[Display omitted] • The structure–activity relationship between different components of DESs and CYC-EA was studied. • Four kinds of extractants for separating CYC-EA by extractive distillation were designed. • The separation performance of DESs for CYC-EA was studied quantitatively and qualitatively. • The VLE experiments of CYC-EA azeotrope separated by four DESs were studied. Selecting the appropriate extractant is of great significance for solving the problems of high energy consumption and difficult separation in the extractive distillation process. In this study, four deep eutectic solvents (DESs) were designed by combining menthol hydrogen bond acceptors with lauric acid and capric acid hydrogen bond donors and tetrabutylammonium bromide hydrogen bond acceptors with levulinic acid and ethylene glycol hydrogen bond donors. The interaction mechanism and structure–activity relationship between azeotropic system, hydrogen bond donor, hydrogen bond acceptor and deep eutectic solvent were studied. σ-profile, interaction energy, reduced density gradient, electrostatic potential, and natural bond orbital were used to study the microscopic mechanism and structure–activity relationship of azeotropes separated by DESs. On this basis, the vapor–liquid equilibrium experiments of separating ethyl acetate-cyclohexane azeotrope by DESs were carried out. The results showed that separating ethyl acetate-cyclohexane by using DESs is feasible and that the DES synthesized by using levulinic acid and tetrabutylammonium bromide is preferable for separation. Studying the relationship between DES structures and the azeotrope provides a theoretical basis for the screening and design of DES extractants for the separation of alkane-ester azeotropes using extractive distillation. [ABSTRACT FROM AUTHOR]

• Hydrophobic PCM and surfactant promote hydrate formation. • Hydrate formation/dissociation with PCM and surfactant has good stability. • There are some crystal plates with addition of CA-DE, but one big crystal with Tween80 or CA-DE + Tween80. • The hydrate growth shows a fractal growth mode with Tween80. • Hydrate growth rates with CA-DE or CA-DE + Tween80 is almost the same everywhere. Surfactant and hydrophobic materials are often used to accelerate hydrate formation. The effects of Tween80, decanoic acid (S10) and dodecyl alcohol (C10) on hydrate crystal growth after the nucleation of hydrate are investigated in this work. The droplets with HCFC-141b enhances hydrate formation. In the cycling procedure of formation and dissociation of hydrate, the hydrate formation with Tween80 has better stability than the system without Tween80. Additives alter the growth mode of hydrate crystal. The hydrate crystals grow at almost the same rate everywhere along the crystal growth direction in the presence of the mixture of decanoic acid and dodecyl alcohol (S10-C10) or S10-C10 + Tween80. However, hydrates grow at different rates at different sites when only Tween80 is used as additive. The hydrate lateral average growth rate (HLAGR) of crystals in the presence of 1 wt% S10-C10 and 1 wt% Tween80 is higher than that in the presence 1 wt% S10-C10. The influence of additives on hydrate crystal morphology is also studied. Clathrate hydrate crystal plates is scattered when S10-C10 is added in this work. When surfactant Tween80 is added in the experimental system, there is only one big clathrate hydrate crystal plate. There are some spicules crystals on the big crystal plate surface in the system of HCFC-141b + Tween80 + H 2 O. [ABSTRACT FROM AUTHOR]

• Gemini surfactant derived from cysteine ​​forms complexes with copper and silver salts. • There is a change in the morphology of the aggregates induced by the metallic salts. • The aggregates change from micelles to vesicles. • There is a redox process involved in the association of the Gemini with Cu (II) • The systems have antimicrobial properties against Gram positive and negative bacteria. Gemini surfactants are amphiphilic molecules formed by two polar heads and two hydrophobic tails joined by a spacer between the polar groups. Their molecular structure gives them particular physico-chemical properties in comparison with their monomeric counterparts. In this work we synthetized a Gemini surfactant (SDDC) derived from the amino acid cystine and decanoic acid. The influence of different metallic salts on the aggregation of the surfactant was studied. SDDC forms core–shell type triaxial ellipsoidal micelles in aqueous solution, but the aggregates suffer a change in morphology, forming vesicles in the presence of copper or silver ions. This behavior was corroborated by TEM and SAXS measurements. With the last technique was possible to estimate that vesicles formed in presence of copper consisted of 7.3 stacked bilayers. It was possible to determine that Cu2+ was reduced to Cu+ in the solution containing SDDC, through EPR and UV–visible spectrophotometry measurements. The reduction of copper was accompanied with the concomitant oxidation of the cystine. The antimicrobial activity of the different aggregates was studied against E. coli and S. aureus and compared with the conventional antibiotic ampicillin. The most efficient system resulted the mixture of SDDC:CuSO 4 /10:1 against the Gram-negative bacterium, there with the minimum concentration used (0.01 mM) was possible to inhibit 70 % of growth. The new systems characterized in this work have many possibilities for potential applications, mainly in the area of drug delivery systems, templates in the synthesis of nanomaterials or as antibacterial compounds. [ABSTRACT FROM AUTHOR]

[Display omitted] • A formulation processing method for dissolving the pesticide active ingredients (PAIs) in DESs was proposed firstly. • The DESs were green, designable, and possessed an excellent capacity for dissolving the PAIs. • Combining the COSMO-RS model to screen DESs was time and labor-saving. • The dissolution mechanism of the PAIs dissolved in DESs was explored. • The effects of different concentrations of DES on wheat seedlings' growth indexes were explored. The solubility of 9 water-insoluble pesticide active ingredients (PAIs) was predicted in 133 deep eutectic solvents (DESs) based on 7 hydrogen bond acceptors and 19 hydrogen bond donors, using a COSMO-RS model. 13 DESs with superior solubility of water-insoluble PAIs were screened out and verified with experiments. The actual measurement results agree well with the forecasting results. When compared with the solubility in pure water, some PAIs can even be mutually dissolvable with tetraethylammonium chloride: decanoic acid (1:2), tetrabutylammonium chloride: decanoic acid (1:3), and tetrabutylammonium chloride: phenol (1:5), such as butachlor, acetochlor, and metolachlor. FT-IR and 1H NMR spectra suggested that hydrogen bonding between DESs and PAIs molecules played a crucial role in solvation. Crucially, the study indicated that it's feasible to replace toxic organic solvents with DESs in emulsifiable concentrates formulations. The effects of different concentrations of tetraethylammonium chloride: decanoic acid (1:2) on the growth of wheat seedlings were also explored. The results showed that it did not affect the germination rate of wheat seeds, but with the increase of concentration, the growth indexes such as the lengths of shoots and roots grew shorter, the fresh weight of aboveground and underground decreased. This study provides COSMO-RS as a valuable and reliable tool to screen DESs, and highlights that DESs can be an alternative to replace toxic and harmful organic solvents in emulsifiable concentrates (EC), which provide ideas and a basis for designing new green pesticide formulations. [ABSTRACT FROM AUTHOR]

[Display omitted] • Stability of hydrophobic deep eutectic solvents (DESs) in aqueous phase. • Effect of hydrogen bond acceptor and donor type on hydrophobic DES stability. • Three-component DESs formation in the presence of water. • DESs based on terpenoids and tetraoctylammonium bromide as stable extractants. Numerous articles have been presented on efficient liquid–liquid extraction procedures from aqueous samples using deep eutectic solvents based on quaternary ammonium salts or natural terpenoids as hydrogen bond acceptors and fatty acids as hydrogen bond donors. However, precursors of these solvents are soluble in the aqueous phase and the composition of the solvents can be changed in the presence of water. In this research the stability and composition of deep eutectic solvents based on quaternary ammonium salts (tetrabutylammonium bromide and tetraoctylammonium bromide), terpenoids (menthol and thymol) and fatty acids (hexanoic, heptanoic, octanoic, nonanoic and decanoic acids) in aqueous phase were systematically investigated. It was shown that all studied two-component solvents are transformed into three-component solvents in the presence of water. Effects of hydrogen bond acceptors and donors type on formation of three-component solvents were investigated and discussed. It was established that, the ratio of aqueous and organic phases plays a key-role for stability of the solvents based on tetrabutylammonium bromide. The solvents based on terpenoids and tetraoctylammonium bromide remain stable in the wide range of phases ratios. In addition to the study of stability, changes in the physicochemical and extraction properties of ternary eutectic solvents in comparison with two-component solvents have been shown. [ABSTRACT FROM AUTHOR]

• A liquid was prepared from capric acid and menthol. • The liquid maintains its liquidity at room temperature and lower temperatures. • The liquid is a hydrophobic low viscosity liquid. • The liquid showed high solubilization power of risperidone. • The liquid is a vehicle with excellent permeation enhancement efficiency. The work outlined herein describes an evaluation of a green solvent working as a drug solubility and penetration enhancer made up of a deep eutectic system (DES) composed of menthol (MN) and capric acid (CA). Risperidone (RIS) was tested as a class II model drug. The system efficacy in enhancing drug solubility was carried out at five different CA: MN mass ratios (w/w) of 7:3, 6:4, 5:5, 4:6, and 3:7. The 7:3 CA:MN (w/w) mass showed the most remarkable solubility improvement of the drug of up to 73000-fold compared to water. The phase-forming mechanics involved in drug-related solubility were demonstrated in this work by studying the mixtures' viscosity and contact angle at the same above-mentioned CA:MA ratios. Moreover, the interactions between the components that constitute the DES were studied using DSC and FTIR analysis. Results confirmed that H-bonds between MN and CA formed the DES. The permeability of the systems was established through diffusion studies carried out using Franz cell. Preparations comprising the drug in DES showed the absence of any acute skin irritation/erosion effect on Wistar rats. [ABSTRACT FROM AUTHOR]

[Display omitted] • Decanoic acid rejects gadolinium (Gd3+) ions. • Solvation free energy of Gd3+ is more favorable in water. • Gd3+-Gd3+ and Gd3+-NO 3 -aggregates with T. In this manuscript, we present an all-atom molecular dynamics (MD) simulation to understand the separation behavior of the gadolinium ions (Gd3+) and its nitrates (NO 3 –) from the aqueous wastewater using directional solvent extraction (DSE) with decanoic acid (DEC) as an extractant. We analyze the detailed structure, dynamic and thermodynamic properties of Gd3+, NO 3 – and water (H 2 O) in the presence of DEC and bulk water (without DEC). DEC forms a bilayer-like structure in pure water and rejects the Gd3+ ions and NO 3 – ions. We have observed the enhanced Gd3+–NO 3 – and Gd3+-Gd3+ association with an increase in T due to the presence of DEC molecules. The diffusion of Gd3+ and NO 3 shows a decrease due to the Gd3+(NO 3) aggregation in water with an increase in T. The solvation free-energy analysis shown more favorable solvation of Gd3+, NO 3, and H 2 O in water when compared to solvation in DEC. Overall this manuscript provides detailed molecular level insights towards the application of DEC as an extractant for Gd3+ removal from radioactive waste using a membrane-free low-temperature DSE process. [ABSTRACT FROM AUTHOR]

[Display omitted] • HDESs based on binary natural antimicrobial including fatty acids and terpenoids were prepared and properties evaluation. • HDES-in-water nanoemulsions were successfully prepared and showed excellent storage, thermal, and pH stability. • The antibacterial effect affected by different types of bacteria, emulsified form, and HDES composition. • This study provides a new perspective on the application of HDES. In this study, hydrophobic deep eutectic solvent (HDES)-in-water nanoemulsions were prepared as potential antimicrobial delivery systems. Firstly, HDESs based on the eutectic mixing of binary natural antimicrobial including medium-chain fatty acids (caprylic acid, capric acid, or lauric acid) and terpenoids (menthol or thymol) were prepared, and their physicochemical properties were studied. Then HDES-in-water nanoemulsion stabilized by a food-grade non-ionic surfactant (Tween 80) was successfully prepared by ultrasonic treatment. Results showed that HDES components have a significant impact on the physicochemical properties of HDESs, such as surface tension, viscosity, and melting point, to affect the mean particle diameter and zeta-potential of the corresponding emulsions. Except for emulsions formed by thymol-based HDES, the mean particle diameter of the emulsions are normally < 100 nm. Besides, both emulsion stability and antimicrobial activity of the nanoemulsions against two foodborne pathogens (Escherichia coli, Staphylococcus aureus) were evaluated. It was found that the nanoemulsion maintained excellent performances in storage, thermal, and pH stability. The antibacterial effect is affected by differernt type of bacteria, emulsified form, and HDES compositions. This work represents the starting point for future applications of HDESs with antibacterial properties in food and other industries. [ABSTRACT FROM AUTHOR]

In this paper, the electrochemical properties of the ternary system ethanol (E) -water (W) -decanoic acid (HC10) in the absence and presence of Cu2+ ions were investigated. The ternary system was considered, as it is often used as a medium in which copper materials are immersed to treat their surfaces with the green inhibitor HC10. This compound is used to prevent corrosion of copper-based materials of cultural heritage interest. The three-component system was made, mainly, of 50%(v /v) E/W and HC10 varying from 1 to 16 mM, while CuSO 4 was employed as source of Cu2+ ions. The measurements were performed using cyclic voltammetry (CV) and a platinum microdisk electrode. CVs, performed in the 50%(v /v) E/W- HC10 solutions, provided a reduction process, involving hydrogen ions released from the weak acid; from the half-wave potential and the diffusion limiting current, the dissociation constant of HC10 was evaluated. The reduction of Cu2+ to Cu0 in the E/W mixture was investigated in detail without and with different amounts of HC10, as well as in the presence of Cl− ions. It was found that Cu2+ interacted slowly with HC10, under the acidic conditions ensuing by the dissociation of the acid itself, and provided soluble copper(II)-carboxylate species. These were reduced at potentials more negative than that due to the reduction of the free Cu2+ ions. The presence of Cl− ions did not provide any sensible change in the CV, apart from the split of the wave, for Cu2+ reduction, due to the formation of the stable CuCl 2 − specie. The layer of copper formed onto the electrode surface, ensuing the reduction of the various free Cu(II) or Cu(II)-carboxylate species present in the solutions, was passivated by the excess or unreacted HC10 in the medium. The decrease of the ethanol content in the E/W mixture below about 40%(v /v) caused the formation of a sparingly soluble compound, identified as Cu(C10) 2 by FTIR analysis. [Display omitted] • Voltammetry in the three-component system ethanol-water decanoic acid is performed. • The reduction of copper ions in the three-component system is investigated. • The reduction of decanoic acid (HC10) proceeds through a CE process. • Copper(II)-decanoate complexes are formed and reduces to metallic copper. • Metallic copper films electrogenerated onto a Pt microdisk is passivated by HC10. [ABSTRACT FROM AUTHOR]

The performance of three hydrophobic carboxylic acid based Deep Eutectic Solvents were evaluated for the extraction of 1-butanol and acetonitrile from aqueous solution. To do so, the phase diagrams of five ternary systems {[DL-menthol: lauric acid] + water + 1-butanol}, {[DL-menthol: capric acid] + water + 1-butanol}, {[DL-menthol: capric acid] + water + acetonitrile}, {[TBAMBr:capric acid] + water + 1-butanol} and {[TBAMBr: capric acid] + water + acetonitrile were measured at 298.15 K at atmospheric pressure. Liquid-liquid equilibria data were used to determine distribution coefficient (β) and selectivity (S) of the solvents. It was found that DL-menthol based DESs are of interest for the extraction of 1-butanol and acetonitrile. NRTL and UNIQUAC models provide a good representation of the phase diagrams measured in this work. COSMO-RS enables to predict phase diagrams of systems containing DL-menthol based Deep Eutectic Solvents with good accuracy. • Three hydrophobic carboxylic acid based Deep Eutectic Solvents (DESs) were prepared. • DESs were applied to butanol or acetonitrile extraction from aqueous mixtures. • Selectivity and distribution coefficients were calculated from LLE data. • LLE were correlated using NRTL model. • COSMO-RS thermodynamic model was applied to LLE. [ABSTRACT FROM AUTHOR]

Headspace gas chromatography mass spectrometry (HS-GC–MS) was used to determine the volatility of six selected hydrophobic deep eutectic solvents (DESs). The partial pressure of each DES constituent (decanoic acid, thymol, 1-tetradecanol, menthol or lidocaine) was measured from 313.15 to 373.15 K. The activity coefficients of the hydrogen bond acceptor (HBA) and the hydrogen bond donor (HBD) were determined to quantify the interactions between the DES constituents, thereby deepening the understanding of the thermodynamic nature of the DESs. In addition, the activity coefficients for both components in each DES were predicted with the UNIFAC group contribution method. Similar trends and reasonably close values were obtained for the measured and predicted activity coefficients. It has been found that the interactions between the DES constituents tend to become weaker with increasing temperature. Strong interactions occur between thymol and lidocaine, and thymol interacts moderately with menthol. A weak force exists between decanoic acid and menthol. The mixtures of menthol with 1-tetradecanol or lidocaine are not strictly DESs since for each DES constituent both the measured and predicted activity value is close to unity. A viscosity study was also carried out to quantify the interactions and similar results were found. The ideal mixing rule was proven to correctly describe the viscosity for the mixture of menthol with 1-tetradecanol or lidocaine. While compared to the ideal mixture viscosity, an increase in viscosity was observed for other studied DESs indicating stronger interactions. Finally, the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) was shown to accurately describe the thermodynamic properties, where the PC-SAFT pure-component parameters for the DESs were obtained by fitting to pure DES density and total vapor pressure data. • Volatility of DES was determined with HS-GC–MS method. • Activity coefficients of DES constituents were predicted with UNIFAC method. • Measured viscosities reflect the interaction strength between DES constituents. • PC-SAFT model was implanted for the description of DESs. [ABSTRACT FROM AUTHOR]