Application of deep eutectic solvents and their individual constituentsas surfactants for enhanced oil recovery (original) (raw)
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Fluid Phase Equilibria, 2017
Several novel applications of Deep Eutectic Solvents (DESs) have emerged recently. With a growing interest in the field, there is an urge to understand formation and functioning of these solvents at molecular level, which in turn would assist in further designing of DESs. We herein performed molecular dynamics simulations on three of the commonly used type III DES, viz, reline, ethaline, and glyceline, which are mixtures of urea, ethylene glycol, and glycerol with choline chloride at eutectic composition. Our results explain the role of inter-molecular and intra-molecular hydrogen bonding and energies on formation of these DESs. Furthermore, the ability of these DESs to be altered in a desired way through a simple addition of water makes it versatile solution for several other applications. Hence, simulations are also performed on the aqueous DES solutions, which reveal the effect of water on intermolecular network of interaction existing within these DESs.
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.
Deep eutectic solvents (DESs) are derived from two or more salts as the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). In this work, six deep eutectic solvents (DESs) were prepared namely allyltriphenyl phosphonium bromide- diethylene glycol (ATPPB-DEG) and allyltriphenyl phosphonium bromide - triethylene glycol (ATPPB-TEG) using three molar ratios of 1:4, 1:10 and 1:16 salt to HBDs. The temperature range for experimental viscosity was from 293.15 to 343.15 K and that of the experimental surface tension was between 298.15 and343.15 K. The results disclosed that hydrogen bonding (H…Br) in DESs has a great effect on the properties. Among all DESs with the same components, the DESs with the strong hydrogen bonding (H…Br) in their structures had the higher viscosity and surface tension. Besides, by increasing the temperature and quantity of HBDs in DESs, both of these properties experienced a decrease decreasing trend in the amount. It was found that the molecular weight of DESs with the same component has an effect on the properties. The higher molecular weight caused the higher viscosity and surface tension. Further, ATPPB-TEG DESs had the higher viscosity and lower surface tension than ATPPB-DEG DESs because of the higher alkyl chain in their structures. Several models and a new empirical equation were used to correlate the experimental viscosity data. It was found that there is a well agreement between theoretical and experimental values especially when the new empirical equation is used. In addition, the activation parameters for all DESs were calculated using the experimental viscosity data and application of Eyring’s absolute rate theory. The experimental surface tension was employed to predict the critical temperature and, surface entropy and internal surface energy of DESs. Finally, two empirical equations were used for relating the experimental surface tension to the experimental viscosity of DESs.
Deep eutectic solvents (DESs) are derived from two or more salts as the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). In this work, DES namely allyltriphenyl phosphonium bromide-diethylene glycol (ATPPB-DEG) was prepared by using three molar ratios of 1:4, 1:10 and 1:16 salt to HBD. The volumetric properties of aqueous DESs, such as density, molar volume, isobaric thermal expansion, apparent molar volume and apparent molar expansibility were reported at several temperatures from 293.15 to 343.15 K. A mathematical equation, namely Jouyban-Acree model (JAM), was used for the first time to correlate the experimental density and molar volume data of aqueous solution of DESs with respect to the concentration and temperature. The results disclosed that this model is an accurate and reliable model for the prediction of aqueous DES properties. The excess properties, such as excess molar volume and excess isobaric thermal expansion were reported and fitted to two different equations. In order to calculate the limiting apparent molar volume values, the apparent molar volume values were fitted into a Redlich-Mayer equation. By applying the Hepler equation, it was found that DESs with molar ratios of 1:4 and 1:10 are as structure-maker solutes, while the DES 1:16 is a structure-breaking solute in aqueous solutions at different temperatures.
Los solventes eutécticos profundos son mezclas compuestas típicamente por un donador de puentes de hidrógeno y un aceptor de puentes de hidrógeno. Han aparecido como una alternativa de los líquidos iónicos en varios procesos debido a su capacidad de adaptación, biodegradabilidad y bajo costo. Recientemente, los solventes eutécticos profundos se han estudiado como solventes potenciales para diferentes aplicaciones. Entonces, sus propiedades fisicoquímicas deben caracterizarse para comprender la interacción entre sus componentes y con otros compuestos. Los solventes eutécticos profundos preparados para este trabajo se basaron en cloruro de colina mezclado con etilenglicol, 1,3-propanodiol o 1,4-butanodiol en una relación molar de 1:3. Se realizan diferentes familias de DES basadas en cloruro de colina y betaína en paralelo para generar una base de datos, ver el ajuste y la predicción utilizando el modelo de esfera dura. La densidad y la viscosidad de los disolventes eutécticos profund...
Journal of molecular liquids_article.pdf
The effect of addition of methanol and ethanol on the micellization of cationic surfactants dodecyltrimethylammonium bromide (DTAB) and cetyltrimethylammonium bromide (CTAB) in aqueous medium have been studied by conductance and surface tension measurements at 298.15 K. Different physicochemical properties such as Gibb's free energy of micellization (ΔG°m), free energy of surfactant tail transfer (ΔG°t rans ), maximum surface excess concentration (Г max ), area occupied by surfactant molecule (A min ), surface pressure at the cmc (π cmc ), packing parameters (P) and standard free energy interfacial adsorption (ΔG°a ds ) are calculated in water, 0.10, 0.20, 0.30 and 0.40 volume fractions of methanol-water and in water, 0.10, 0.20, 0.30, 0.40, 0.50 and 0.60 volume fractions of ethanol-water respectively at 298.15 K. Addition of alcohol significantly affects the physicochemical properties of both DTAB and CTAB. With increasing concentration of alcohol, cohesive force and dielectric constant decrease that affects the micellization and other physicochemical properties. However, at the higher volume fraction of ethanol-water a slight variation of properties are seen. The micellization of DTAB and CTAB have been assessed in terms of different solvent parameters. The ratio of the solvent surface tension to the limiting surface tension at the cmc has been used as the solvophobic effect. The solvophobic parameter characterized by Gibbs energy of transfer of hydrocarbon from gas into a given solvent can be used to account for the effect of alcohol on the formation and growth of the cationic surfactants aggregate in water.
Prediction of the surface tension of deep eutectic solvents
Fluid Phase Equilibria, 2012
Surface tension is one of the important deep eutectic solvents (DESs) physical properties which provides considerable information related to the molecular influence on the intensity of interactions in the mixture. Due to the absence of DESs surface tension experimental data, prediction methods of this property become of high importance. In this work, two simple methods for the prediction of DESs surface tension are presented. The first method reports the use of the parachor to predict surface tension. In the second method, the effect of temperature variation on surface tension was predicted using the Othmer equation. The parachor of nine different DESs based on ammonium and phosphunium salts were determined experimentally as well as calculated from the molecular structure of their constituting components using available parachor contribution data for neutral compounds. The results showed that calculated and experimental parachor of DESs were notably close and that the parachor contribution data developed for neutral compounds can be successfully utilized for deep eutectic solvents with an average surface tension prediction percentage error of 6.4%. The average prediction percentage error using the Othmer equation was 2.57%. This proves that surface tension of DESs can be predicted efficiently using either one of the two suggested methods.
Structural analysis of natural deep eutectic solvents. Theoretical and experimental study
Microchemical Journal, 2018
A theoretical and experimental study was performed on natural deep eutectic solvents (NADES) formed by lactic acid-glucose (LGH), citric acid-fructose (CFH), and citric acidglucose (CGH). The presence of nuclear Overhauser effect (NOE) in the proton nuclear magnetic resonance (1 H NMR) spectra of the NADES was studied. The spatial proximity between the NADES components was experimentally confirmed by the detection of multiple NOE effects in the dilutions analyzed. LGH showed the best outcome by partially maintaining theirits supramolecular structure throughout the dilutions. In order to rationalize the intermolecular interactions generated among the components, a theoretical study was performed using a density functional theory (DFT) computational method. A simplified dimeric model of the NADES was selected in order to achieve a rapid screening of the system searching for interactions between their constituents. In agreement with the experimental evidence, the calculations allowed to confirm the spatial proximity, by finding at least two hydrogen bonds between the components of every NADES.
Novel Contribution to the Chemical Structure of Choline Chloride Based Deep Eutectic Solvents
At the beginning of this century, new generation of solvents, named Deep Eutectic Solvents (DES) has been reported . DES is defined as a mixture of hydrogen bond donor (HBD) with hydrogen bond acceptor (HBA) which produces liquids. Abbott's fundamental work inspired other researchers to exploit the unusual properties of this system . The physicochemical properties of DESs resemble those of ionic liquids .