Molar Gibbs Free Energy Research Articles

Electrochemical behavior and separation of dysprosium from molten NaCl-KCl eutectic by co-reduction with aluminum

To electrolytically separate dysprosium from spent fuel, the electrochemical behavior of Dy3+ and its co-reduction process with Al3+ on inert Mo electrode in molten NaCl-KCl eutectic was systematically investigated employing a series of electrochemical methods. Dy3+ ions were directly reduced to dysprosium metal on inert Mo electrode through one step with three electrons exchanged. The reduction of Dy3+ was considered to be a quasi-reversible process, and the deposition of dysprosium on Mo follows the progressive nucleation mode. However, the co-reduction of Dy3+ with Al3+ on the Mo electrode allows the reduction of Dy3+ at more positive potentials because of the formation of Dy-Al intermetallics. The electromotive force method was then adopted to determine the thermodynamic properties of the Dy-Al intermetallics, such as the relative partial molar Gibbs free energy and the activity of dysprosium, and the standard formation Gibbs energy for Dy-Al intermetallics. Finally, potentiostatic electrolysis was conducted to extract Dy-Al alloys from the NaCl-KCl-0.40mol%DyCl3-0.56mol%AlCl3 melts. The XRD and FE-SEM/EDS analyses indicated that DyAl3, DyAl2 and DyAl intermetallics and metallic Al were generated in the products by electrolysis at −1.8 V, while the dysprosium-rich phases of DyAl2 and DyAl were produced as electrolysis at −2.0 V. The electrochemical separation of dysprosium from molten NaCl-KCl eutectic on inert Mo electrode was proved to be practically feasible by co-reduction with aluminum.

SYNTHESIS, SPECTROSCOPIC, THERMAL AND BIOLOGICAL STUDIES of SOME NOVEL METAL IONS COMPLEXES

In the current study, a novel heterocyclic azo ligand, 4-[6-(p-phenyl phenol)azo] cytosine(PAC), is synthesized through a general diazo coupling reaction with lanthanide ions [La(III), Nd(III), and Eu(III)]. The molecular formulae of the newly synthesized compounds were established using a variety of spectroscopic methods, including [FT-IR, UV-Vis, and HNMR], elemental analysis (C.H.N), thermal gravimetric analysis (TGA), magnetic measurement, molar conductivity measurement, stability constant, and Gibbs free energy. Using the mole ratio method, the complexes stoichiometry was determined using data from spectroscopic analyses of the complexes' solutions for the chosen ions. The metal to ligand mole ratio, however, was (1:2). When the biological effectiveness of each compound was tested against various bacteria and fungi strains, the results showed good activity when compared to the standard medication. additionally possess effective cancer prevention and dyeing performance

Measurement and accurate prediction of surface tension for VOSO4-H2SO4-H2O ternary electrolyte system at high-concentration in vanadium redox flow batteries

Surface tension is an important thermodynamic parameter for vanadium redox flow battery (VRFB) however its related theoretical study for multicomponent systems containing sulfuric acid at high concentration is rare due to the complexity of ion interaction in the electrolyte. In this work, the surface tension and density of VOSO4-H2SO4-H2O electrolyte solution were firstly measured at different temperatures from 283.15 to 313.15 K over a wide range of solute concentration. The average molar volume (V) was calculated according to above experimental data, and then the new definition of molar surface Gibbs free energy (gs) and improved Eötvös equation for VOSO4-H2SO4-H2O ternary solution has been derived based on Li’s theory. Simultaneously, several thermodynamic data of this ternary solution were obtained, such as the value of molar surface entropy, s, molar surface enthalpy, h, and Eötvös empirical parameter. In addition, the high-accuracy and semi-empirical equation was established to predict the surface tension of the VOSO4-H2SO4-H2O ternary solution based on the new gs definition. The results revealed that predicted values are in good agreement with the experimental values and correlation coefficient is 0.9993. This work provides basic data for mass transfer and heat transfer analysis of the VRFB and it also provides convenience for evaluating the interface effect between the electrolyte and other components when optimizing the composition of electrolyte and improving battery performance.

Theoretical prediction of Gibbs free energy and specific heat capacity of gaseous molecules

• Highly efficient equations for the prediction of molar Gibbs free energy and molar specific heat capacity are presented. • The equations are based on the improved generalized Pöschl-Teller oscillator. • The analytical models are applicable to large class of diatomic and triatomic molecules. • The equations require only three molecular constants of the molecule as input data. Using the improved generalized Pöschl-Teller oscillator to model the internal vibration of a diatomic molecule, analytical equations to predict molar Gibbs free energy and specific heat capacity at constant pressure were obtained. The equations were applied to ground-state Br 2 , Cl 2 diatomic molecules, and CO gaseous molecule. Average absolute deviations of 0.0755%, 0.0787%, and 0.3583%, were obtained using the equation of reduced molar Gibbs free energy. The expression of molar specific heat capacity yielded average absolute deviations of 4.5055%, 2.5308%, and 2.3665%, respectively from experimental data for the diatomic molecules. The results are in good agreement with existing literature data on the diatomic molecules.

Thermodynamics of trimethyltetradecylammonium bromide – Sodium deoxycholate binary mixed micelle formation in aqueous solution: Regular solution theory with mutual compensation of excess configurational and excess conformational entropy

A binary mixture of trimethyl(tetradecyl)ammonium bromide = TB-SD = sodium deoxycholate surfactants forms non-ideal binary mixed micelles that have molar excess Gibbs free energy described with the Margules function of the first order. Strong synergistic interactions exist between TB and SD particles (interaction coefficient with a magnitude of 10). Based on the temperature dependence of interaction coefficient and temperature dependence of TB and SD micellar molar fractions product logarithm, it follows that the molar excess entropy is zero. Therefore, although the surfactants TB and SD are structurally very different, their binary mixed micelles can still be described with regular solution theory (random mixing of TB and SD). However, the 2D ROESY spectrum indicates that the binary micellar pseudophase is not random in terms of the spatial distribution of TB and SD particles. Namely, intermolecular interactions between deoxycholic acid anions are missing in the binary mixed micelle. This results in the appearance of excess configuration entropy. However, a zero value of the total molar excess entropy and the existence of the first order Margules function for the molar excess Gibbs free energy means that the molar excess configurational entropy is compensated with the molar excess conformational entropy and that there are correlation effects between the excess configurational enthalpy and entropy as well as between the excess conformational enthalpy and entropy.

Measuring and modeling the solubility of carbon dioxide in protic ionic liquids

The solubility of carbon dioxide (CO2) in three protic ionic liquids, namely N-Ethylmorpholine acetate ([NEMH][Ac]), N-Ethylmorpholine propionate ([NEMH][Pro]), and Triethylamine propionate ([TEAH][Pro]), was measured at temperatures from 298.15 to 338.15 K and pressures up to about 900 kPa. The solubility data were fitted by Pitzer's model and Soave-Redlich-Kwong (SRK) cubic equation of state. In the range of experimental uncertainty, both models can well correlate solubility data. Henry's law constants of CO2 in these three protic ionic liquids at zero pressure were estimated from the solubility data, and the partial molar Gibbs free energy, partial molar enthalpy, and partial molar entropy at infinite dilution were calculated.

Interaction between Triton X100 and Brij 58 in their binary mixed micelles: Micellization in aqueous solution and aqueous solution of Poloxamer 188 at the range of temperature T = (273.15–323.15) K

The micellization of the binary mixture of surfactants Triton X100 – Brij 58 in an aqueous solution (with and without Poloxamer 188) was investigated using a spectrofluorimetric method with pyrene as a probe molecule. There are synergistic interactions between the micellar building units in the binary mixed micelles Triton X100 – Brij 58, which increase with increasing temperature. The analyzed binary mixed micelles possess molar excess entropy. The molar excess Gibbs free energy is a first-order Margules function from the surfactant (Triton X100 or Brij 58) molar fraction in the binary mixed micelles Triton X100 – Brij 58. Poloxamer 188, in the temperature range T = (273.15–323.15) K, does not form micelles. Poloxamer 188 in an aqueous surfactant solution (0.01 w/w) reduces the thermodynamic stabilization of the binary mixed micelle Triton X100 – Brij 58 concerning the state of the same binary mixed micelle when this polymer is not present in an aqueous solution. In the presence of Poloxamer 188, the thermodynamic destabilization of the binary mixed micelle Triton X100 – Brij 58 increases with increasing temperature.

The effects of diffusional couplings on compositional trajectories and interfacial free energies during phase separation in a quaternary Ni-Al-Cr-Re model superalloy

The temporal evolution of ordered γ′(L12)-precipitates and the compositional trajectories during phase-separation of the γ(face-centered-cubic (f.c.c.))- and γ′(L12)-phases are studied in a Ni–0.10Al-0.085Cr-0.02Re (mole-fraction) superalloy, utilizing atom-probe tomography, transmission electron microscopy, and the Philippe-Voorhees (PV) coarsening model. As the γ′(L12)-precipitates grow, the excesses of Ni, Cr and Re, and depletion of Al in the γ(f.c.c.)-matrix develop because of diffusional fluxes crossing the γ(f.c.c.)/γ′(L12) heterophase interfaces. The coupling effects on diffusional fluxes are introduced (PV coarsening model) in terms of the diffusion tensor, D, and the second-derivative tensor of the molar Gibbs free energies, G″, obtained employing Thermo-Calc and DICTRA calculations. The Gibbs interfacial free energies, σγ/γ′, are (6.9 ± 1.4) mJ/m2 with all terms in D and G″, which changes to (18.9 ± 2.1) mJ/m2, (37.7 ± 3.3) mJ/m2, and (-7.5 ± 1.2) mJ/m2 when not including the off-diagonal terms in D, G″, and both D and G″, respectively. The experimental APT compositional trajectories are displayed and compared with the PV model in a partial quaternary phase-diagram, employing a partial tetrahedron. The compositional trajectories measured by APT exhibit curvilinear behavior in the nucleation and growth regimes, t < 16 h, which become vectors, moving simultaneously toward the γ(f.c.c.) and γ′(L12) conjugate solvus-surfaces, for the quasi-stationary coarsening regime, t ≥ 16 h. The compositional trajectories for t ≥ 16 h are compared to the PV model with and without the off-diagonal terms in D and G″. The directions, including the off-diagonal terms in the D and G″tensors, are consistent with the APT experimental data.

Nd3+-Y3Al5O12 system: Iso-valent substitution driven structural phase evolution and thermo-physical behavior

The present work reports structural and thermophysical investigation in Nd3+- substituted Y3Al5O12 (YAG). In addition to being an interesting system for studying the effect of isovalent substitution on phase/structural evolution in a garnet system, it has direct relevance as an inert matrix for burning minor actinides (MA: Am, Cm, and Np) for reducing the long-term radiotoxicity of nuclear wastes. More importantly, garnet has superior thermal conductivity than the zirconia-based systems which are widely being explored for this application. In order to investigate the phase miscibility and resulting thermophysical behavior, fourteen nominal compositions in Y3-xNdxAl5O12 (0.0 ≤ x≤ 3.0) system (Nd3+: chosen as the surrogate for MA) were synthesized by gel combustion followed by variable temperature annealing. The atomistic-level mixing ensured high solubility (33 mol% at 1273 K) of Nd3+ in YAG retaining the garnet-phase but the solubility reduced (13 mol%) upon annealing at 1773 K. Raman spectroscopy supported the phase evolution with composition and temperature. The microstructure of select compositions was investigated using SEM/EDS. Nd3+ caused dilation of garnet lattice, increase in average thermal expansion, and lowering of thermal conductivity. It must be emphasized that Nd-doped garnet still possessed better thermal conductivity compared ZrO2-based systems, a desirable attribute for matrices for MA-transmutation. Other important thermodynamic functions such as molar heat capacity, entropy and molar Gibbs free energy were determined. The study exhibits (a) roles of ionic size, synthesis route, temperature on phase relations upon isovalent substitution in YAG; (b) validation of the thermophysical performance of YAG-type material for MA transmutation.

Uncover the effect of solvent and temperature on solid-liquid equilibrium behavior of 2-bromodibenzofuran

The effects of solvent properties and temperature on the solid–liquid equilibrium of 2-bromodibenzofuran (NSC 1735) were investigated for the first time in terms of temperature, solvent polarity, hydrogen bonding donor and acceptor tendency, as well as cohesive energy density. Firstly, the equilibrium solubility of 2-bromodibenzofuran in 12 mono-solvents, such as alcohol, ketone, nitrile and ester, was determined by gravimetric method ranging from 278.15 ∼ 343.15 K. The values of the mole fraction solubility of NSC 1735 in all the selected solvents increased with increasing temperature. Moreover, the statistical correlations between temperature and solubility were described by the modified Apelblat equation, λh equation, Van’t Hoff equation, and NRTL model. The calculated ARD% values show that the correlation results agree well with the experimental date and the modified Apelblat equation receives the best regression performance. Solvent polarity and cohesive energy density mainly determine the solubility of NSC 1735 in various solvents. Thermodynamic studies of dissolution have shown that the dissolution of NSC 1735 in selected solvents.is endothermic and enthalpy driven. The change of dissolution enthalpy is the main contributor to the molar Gibbs free energy during the dissolution process.

Combining biodegradable surfactants and potassium inorganic salts for efficiently removing polycyclic aromatic hydrocarbons from aqueous effluents

The use of aqueous solutions of non-ionic surfactants like Tergitol 15-S7 and Tergitol 15-S9 is proposed for the first time to ex-situ remediation of Phenanthrene, Pyrene and Benzo[a]anthracene polluted soils, thus generating aqueous Polycyclic Aromatic Hydrocarbons (PAH)-polluted effluents. The effectiveness of several potassium based-inorganic salts (K3PO4, K2HPO4, K2SO4, K2S2O3 and K2CO3) to act as PAHs extractants was evaluated. The immiscibility region of the aqueous solutions was determined at room temperature, correlated by three empirical equations and compared with other non-ionic surfactants belonging to Tween and Triton families. The segregation capacity of the salts was analyzed in the light of their water-structuring degree and molar Gibbs free energy of hydration (ΔhydG). Tie-line determination was the tool used to determine the more viable PAHs removal strategy. Thus, the efficiency of combining K3PO4 to salt out Tergitol 15-S9 aqueous solutions polluted with the selected PAHs was investigated. The extraction percentage of the pollutants was 75% of Benzo[a]anthracene, 72% of Phenanthrene and 60.5% of Pyrene. The process was simulated at real scale through SuperPro Designer v.8.5 for the treatment of 156,000 tons/year of PAH-polluted soil.

Electrochemical extraction of uranium from U3O8 by preparing flower-shaped Al-U intermetallics in LiCl-KCl-AlCl3 melts

This work presents the electrochemical behavior of U3O8 and the formation of Al-U intermetallics in LiCl-KCl-AlCl3 melts at 813 K by various electrochemical test methods. The signals of three intermetallics attributed to Al2U, Al3U and Al4U were detected in the electrochemical curves. The standard Gibbs free energy of formation of Al-U intermetallics, the partial molar Gibbs free energies and activity of U in two phase coexisting states were calculated based on the open circuit chronopotentiometry at 813 and 843 K. U was extracted from U3O8 by forming Al-U intermetallics on Al sheet via potentiostatic electrolysis at -2.0 V in LiCl-KCl-AlCl3-U3O8 molten salt. The X-ray diffraction (XRD) indicated that Al4U, Al3U and Al2U phases were formed. The densely arranged flower-shaped Al-U intermetallics were characterized by scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS). In addition, the extraction efficiency of U(IV) was 92.3% after potentiostatic electrolysis at -2.0 V for 10 h.

Thermodynamic properties of binary systems containing 1-allyl-3-methylimidazolium dicyanamide [Amim][DCA] with short chain alcohols and prediction of surface tension based on molar surface Gibbs free energy

BackgroundAllyl functionalized ionic liquids (ILs) are widely used because of their excellent properties, to increase their applications in industry and academic community, preparing binary mixtures containing ILs and organic solvents is an effective way, and it is essential to further explore the thermodynamic properties of them. MethodsHere, we reported the synthesis and characterization of the ILs 1-allyl-3-methylimidazolium dicyanamide [Amim][DCA]. Then, in the temperature range of 288.15 K–318.15 K, the values of density and surface tension of 1-allyl-3-methylimidazolium dicyanamide, methanol, ethanol, propanol and corresponding binary systems were measured at every 5 K in the full molar concentration. The values of surface tension deviation Δγ, excess molar volume VE and molar surface Gibbs free energy gs of the mixtures were calculated. In addition, the modified Eӧtvӧs equation is derived based on gs, and the values of surface tension of binary mixtures are estimated. Significant findingsThe results show VE are negative, which is mainly due to the tight packing and hydrogen bond, the formation of hydrogen bond has been confirmed by infrared spectroscopy. The Δγ values of 1-allyl-3-methylimidazolium dicyanamide + methanol are positive, while that of the other two are negative. The modified Eӧtvӧs equation has a clear physical meaning. Moreover, the predicted values are in good agreement with the measured ones.

Analytical prediction of enthalpy and Gibbs free energy of gaseous molecules

By employing the improved deformed Pöschl-Teller oscillator to describe the internal vibration of a diatomic molecule, new equations for predicting the molar enthalpy and Gibbs free energy of diatomic molecules were obtained. The equations were applied to the ground states phosphorus, nitrogen, and iodine monochloride molecules. Average absolute deviations of 0.8178%, 3.1939%, and 0.5312% from experimental data were obtained using the molar enthalpy equation. The analytical expression of Gibbs free energy yields average deviations of 0.3865%, 0.4360%, and 0.0405% for the diatomic molecules. The results are in good agreement with available literature data on P2, N2, and ICl gaseous molecules.

Insight into the solute-solvent interactions by physicochemical and excess properties in binary systems of the ether- and allyl-based functionalized ionic liquids with acetonitrile

• The ether- and allyl-based functionalized ionic liquids [C 1 OC 2 pyrr][DCA], [C 1 OC 2 pyrr][NTf 2 ] and [Amim][NTf 2 ] were synthesized and characterized. • The excess properties α p E and V E values are all negative, which could be interpreted in terms of H-bonding interaction and structural effect, and Δ n D findings are also well supported by the results. • The molar refraction, R m and the molar polarizability α, which suggest that the existent interactions between ILs and acetonitrile are ion-dipole interactions. Ionic liquid is a significant new media and one of the most compelling solvents mentioned in many fields. It is clear that the introduction of ether or allyl group has the advantages of low viscosity and wide application. In this work, [C 1 OC 2 pyrr][DCA], [C 1 OC 2 pyrr][NTf 2 ] and [Amim][NTf 2 ] were synthesized and characterized. The density, surface tension, and refractive index of the three ionic liquids and their binary systems with acetonitrile were investigated across a complete composition range. The thermal expansion coefficient ( α p E ), excess molar volumes ( V E ), and refractive index deviations (Δ n D ) are also calculated. The α p E and V E are all negative while the Δ n D are found positive in the entire concentration range, indicating the presence of strong interactions between ionic liquids and acetonitrile. The properties are fitted to a Redlich-Kister equation and the results have been interpreted in terms of H-bonding interaction and structural effect, at the same time, the corresponding IR spectra are also carried out. The molar refraction and the molar polarizability calculated which suggest that the existent interactions between ionic liquids and acetonitrile are ion-dipole interactions. The molar Gibbs free energy can be measured and explained properly by the improved Eӧtvӧs equation. And the molar surface enthalpy also can be gained and is a temperature-independent constant.

Prediction of thermodynamic properties for sulfur dioxide

We report a novel formulation representation of the molar Gibbs free energy for sulfur dioxide (SO2), which depends only on experimental values of six molecular constants of SO2, whereas the conventional explicit representations contain many adjustable coefficients determined from fitting a great number of experimental spectroscopic data or calorimetric data. The formulation representation of the molar entropy for SO2 is also developed from the Gibbs free energy representation. The predicted reduced molar Gibbs free energy and entropy values yield the average absolute deviations of 0.0750 % and 0.228 % from the data reported in the National Institute of Standards and Technology database at the pressure of 0.1 MPa and in the temperature range from 298 to 6000 K, respectively. The proposed formulation representation of the Gibbs free energy for SO2 can be valuable in practical engineering applications.

Influence of hydrogen bond donor on zinc chloride in separation of binary mixtures: Activity coefficients at infinite dilution

Deep eutectic solvents are solvents similar to the ionic liquids (ILs) but less expensive and simple to prepare than ILs. The activity coefficients at infinite dilution of solutes in the deep eutectic solvents (DESs) plays an important role in designing of the separation processes. Gas liquid chromatography technique (GLC) was used to determine activity coefficients at infinite dilution for 34 polar and non-polar organic solutes: solutes include alkanes, alkenes, alcohols, ketones, thiophene, heterocyclics, cycloalkanes, acetonitrile, tetrahydrofuran, cycloalkenes, aromatic hydrocarbon and water in two zinc chloride based DESs [zinc chloride + acetic acid] (1:4) and [zinc chloride + phosphoric acid] (1:2.5) at temperatures (313.15, 323.15, 333.15, 343.15, 353.15) K. Excess thermodynamic parameters [partial molar excess enthalpies ΔG1E,∞,entropies(TrefΔS1E,∞) and Gibbs free energies (ΔG1E,∞)] were derived from activity coefficient at infinite dilution data. The selectivity and capacity values for separation of benzene/ethanol, cyclohexane/ethanol, n-octane/acetonitrile, ethylbenzene/butan-1-ol, n-heptane/butan-1-ol at T = 323.15 K were calculated and compared to literature values for DESs, ionic liquids (ILs), and sulfolane to assess the suitability of the DESs for possible use as an entrainers. Both DESs [zinc chloride + acetic acid] (1:4) and [zinc chloride + phosphoric acid] (1:2.5) have high selectivity values as compared to studied ionic liquids as well as conventional solvents in the literature for difficult separation system of benzene/ethanol, cyclohexane/ethanol, ethylbenzene/butanol and heptane/butanol which indicate that these DESs are an extraction solvent and has separation ability for difficult separation system of benzene/ethanol, cyclohexane/ethanol, ethylbenzene/butan-1-ol and n-heptane/butan-1-ol.

Thermodynamic models of multicomponent nonstoichiometric solution phases using internal process order parameters

Many multi-component compounds are nonstoichiometric due to the competing energetic and entropic thermodynamic contributions at finite temperatures. In CALPHAD-type thermodynamic descriptions, their chemical potential or molar Gibbs free energy at a given temperature is often expressed as a function of site fractions or occupation probabilities of different atomic/ionic/defect species on different sublattices. However, these site fractions are generally not independent from each other due to internal processes involving atomic exchange reactions, redox reactions, and defect formation. Here, we propose a general, systematic thermodynamic description of nonstoichiometric compounds by introducing a set of order parameters describing the extent of these internal processes. The equilibrium state at a given temperature and an overall chemical composition is then obtained by minimizing the chemical potential of a compound with respect to these order parameters. We demonstrate the mutual relationships between site fractions and order parameters using two types of practically important multicomponent phases as examples: perovskite La1−xSrxMnO3 (LSM) and LaxSr1-xCoyFe1-yO3 (LSCF) used as solid oxide fuel cell cathodes and the spinel Co-Fe-O system as a catalyst for CO oxidation. We demonstrate that this proposed thermodynamic model can be directly incorporated in kinetic modeling, e.g., phase-field simulation, of diffusion-reaction and phase transformation processes involving nonstoichiometric phases as well as the kinetics of the internal processes within the nonstoichiometric compound under non-equilibrium conditions. Thus, a general link can be established between thermodynamic databases in terms of site fractions and phase-field simulations of kinetic processes and microstructure evolution using order parameters.

Improved q-deformed Scarf II oscillator

In this work, the improved q-deformed Scarf II oscillator (IQSO) is formulated through the Varshni conditions for diatomic molecule potential. Equation for bound state energy eigenvalues of the IQSO is obtained by the SUSYQM method, a Pekeris-like approximation scheme is used to model the centrifugal term of the Schrödinger equation. Expressions for molar entropy and Gibbs free energy are deduced for the IQSO from equations of energy eigenvalues and partition function within the context of Poisson summation formula. The IQSO is used to model experimental Rydberg-Klein-Rees (RKR) data of six diatomic molecules including: KRb (B 1Π), CO+ (X 2Σ+), Cl2 (X 1Σg +), ICl (X 1Σg +), NbO (X 1Σ+), and K2 (X 1Σg +). The average absolute deviation and mean absolute percentage deviation are used as accuracy indicators. Computed data revealed that the IQSO is an excellent model in fitting the RKR data of the diatomic molecules examined in this work. Numerical values of molar entropy and Gibbs free energy calculated for ICl (X 1Σg +) molecule are almost indistinguishable from existing experimental data for gaseous ICl (X 1Σg +) molecules. This suggests that the IQSO is a near perfect model for representing the internal vibrations of the ICl (X 1Σg +) molecule.

Deep eutectic solvent as a possible entrainer for industrial separation problems: Pre-screening tool for solvent selection

Deep eutectic solvents, as a new type of nature-welcoming solvents, have shown a great interest in different areas of science and in solvent extraction for industrial separation processes. In this present study, the infinite dilution activity coefficients γ13∞, have been measured for 31 volatile organic solvents (alkanes, alkenes, alkynes, aromatics, cycloalkanes, cycloalkenes, alcohols, ketones, and thiophene) in the deep eutectic solvent (1-ethyl-1-methylpyrrolidinium bromide + glycerol) prepared at (1:2 molar ratio) measured at temperature ranging from T = (313.15 to 343.15) K and at atmospheric pressure using gas liquid chromatography coupled with thermal conductivity detector (GC-TCD). The values of the partial molar excess enthalpies (ΔH1E,∞), entropies (TrefΔS1E,∞), and Gibbs free energy (ΔG1E,∞) at infinite dilution were calculated from the experimental data of γ13∞ attained over the temperature range mentioned above. Selectivities and capacities for two separation problems (cyclohexane/benzene and acetone/ethanol) were calculated fromγ13∞ and compared to the other investigated DESs, ILs as well as the currently used traditional solvents found from the literature. Furthermore, the selectivity and capacity results proved that the examined DES cannot be utilized in separation of (acetone/ethanol) but can be utilized for cyclohexane/benzene separation.