Entire Mole Fraction Research Articles

Volumetric and ultrasonic studies of molecular interactions in binary mixtures of N,N-dimethylacetamide with some polyethylene glycols at temperatures from 293.15 to 323.15 K

The intermolecular interactions in N,N-dimethylacetamide (DMA) + polyethylene glycol (PEG) mixtures have been examined from the measurements of the densities, ρ and speeds of sound, u of DMA + PEG 200 or PEG 300 or PEG 400 or PEG 600 mixtures over the entire mole fraction range at temperatures, T = (293.15–323.15) K and atmospheric pressure. Various excess parameters, viz., excess molar volume, excess isentropic compressibility, excess intermolecular free length, excess speed of sound, excess molar isentropic compressibility and excess acoustic impedance were evaluated using measured data. These excess properties were correlated with the Redlich–Kister equation. In addition, the partial molar volume and compressibility; excess partial molar volume and compressibility of the components over the entire composition range; and partial molar volume and compressibility and excess partial molar volume and compressibility of the components at infinite dilution have also been calculated. These evaluated parameters have been interpreted by means of prevailing intermolecular interactions in these mixtures. The presence of strong intermolecular interactions among DMA and PEG molecules have been revealed from the evaluated parameters of these mixtures. The speeds of sound were predicted theoretically using scaled particle theory and compared with experimental values. FT-IR spectra of pure DMA, PEG 200 and their equimolar mixtures were also recorded and analysed for better understanding of prevailing intermolecular interaction.

The eutectic and physicochemical properties of the carboxylic-acid-based deep eutectic solvents

The excellent performance of the deep eutectic solvent (DES) is consistent with the 12 Principles of Green Chemistry. It is of importance to study the DES’s structural characteristics, thermophysical properties and physicochemical properties, especially the DES’s solid–liquid-equilibrium phase diagrams in the entire mole fraction. In this work, ten DES were prepared using tetrabutylammonium bromide as the hydrogen bond acceptor, and octanoic acid/hexanoic acid as the hydrogen bond donors. The molar ratio ranged from 1:1.25 to 1:4. Then, the solid–liquid-equilibrium phase diagrams were obtained. The eutectics and the corresponding eutectic points were discovered. The nuclear magnetic resonance spectra and the Fourier transform infrared spectra were applied to analyze the interactions in DES. The densities and viscosities of the prepared DES were measured. With the optimized Lydersen-Joback-Reid method combined with Lee-Kesler rules, the critical properties were predicted. And then the results were verified through a density prediction model. The average absolute relative deviation (AARD) is better than 1.38%. The mass-connectivity-index-based model was introduced for density prediction with AARD of less than 0.17%. For the viscosity, the Arrhenius equation was compared with an equation considering the molar mass. The AARD of them were less than 2.68 % and 0.69 %, respectively.

Density, Viscosity, Refractive Index, Speed of Sound, Molar Volume, Isobaric Thermal Compressibility, Excess Gibbs Activation for Fluid Flow, and Isentropic Compressibility of Binary Mixtures of Methanol with Anisole and with Toluene at 298.15 K and 0.1 MPa

Density, viscosity, refractive index, and ultrasonic velocity were measured for the pure materials anisole, methanol, and toluene, and for the binary mixtures: methanol—anisole and methanol—toluene. Excess molar volume VE, isobaric thermal compressibility α, excess Gibbs activation energy for fluid flow ΔGE*, and excess isentropic compressibility κSE were calculated from the measured quantities. For both binary mixtures VE and κSE were <0 while Δn > 0 and ΔGE* > 0 over the entire mole fraction composition range. Anisole mixtures exhibited more negative values for VE and κSE while more positive values were displayed for Δn and ΔGE* compared to toluene mixtures. For Δη, negative values were observed at low alcohol concentrations but positive values at high alcohol concentrations for both systems.

Density, viscosity, excess properties, and intermolecular interaction of propylene glycol methyl ether + 1,2-propylenediamine binary system

In this work, the systematic measurements of physicochemical properties, viz., density (ρ) and viscosity (η) values of propylene glycol methyl ether (PGME) + 1,2-propylenediamine (1,2-PDA) binary system, including pure substances, over the entire mole fraction range at the temperatures of T/K = (298.15 to 318.15) under atmospheric pressure of P = 100.5 kPa. The fundamental data were used to calculate several excess properties, including excess molar volume (VmE), viscosity deviation (Δη), and excess activation Gibbs free energy (ΔG∗E). Meanwhile, the work further investigated the values of thermal expansion coefficient (αp), partial molar volume (V¯) and apparent molar volume (Vφ), thereby offering a comprehensive understanding on non-ideal behavior of the binary system. Furthermore, the variations in ρ values with various molar ratios and temperatures were evaluated through Jouyban-Acree model and nonlinear least squares method. Simultaneously, Grunberg-Nissan model, Eyring-Margules model, Heric model, and McAllister model, were used to fit the dependence of η values on the molar ratio. Arrhenius equation was employed to fit the temperature dependency of η values. In addition, Redlich-Kister (R-K) equation was utilized to fit the VmE, Δη, and ΔG∗E values of binary system. Based on spectral analyses of Raman, ultra-violet (UV), and 1H Nuclear Magnetic Resonance (NMR) and density functional theory (DFT) calculation, the intermolecular hydrogen bond (IHB) of PGME with 1,2-PDA was discussed in depth.

Volumetric properties of three nonylphenol ethoxylated nonionic surfactant mixtures with methanol: Experimental study and modeling with Tammann-Tait and PC-SAFT equation of state

Although physicochemical properties are essential for production and equipment design in oil and gas industries, there is still a lack of data for some systems because of hazardous temperature and pressure conditions. This work provides a volumetric behavior study of three different mixtures composed of nonylphenol ethoxylated nonionic surfactant (IGEPAL CO-520, CO-630, and CO-720) + methanol in the entire mole fraction composition range for temperatures from 313.15 K to 413.15 K and pressures up to 100.0 MPa. These systems behave as a regular liquid, with a volume contraction predominance. It was observed that for high methanol molar content, there is an increase in the cohesive forces because of the ethoxylated chain increases in oxyethylene units. Nevertheless, it was observed that the hydrogen bonds between ether oxygens and hydroxyl hydrogens decrease by increasing temperature, as given by internal pressure data and PC-SAFT modeling. Besides, a new set of parameters for the PC-SAFT equation of state is provided to calculate volumetric and second-order derivative properties.

Solubility of fructose and sucrose in mixtures of methanol and water: Experiment and application of equations of state and activity coefficient model

Beyond biochemical functions, carbohydrates have great industrial and economic importance. To improve industrial processes and to develop new applications for these substances, the knowledge of their solubility behavior in different solutions is often necessary. Therefore, the purpose of this work was to collect experimental data on the solubility of fructose and sucrose in hydroalcoholic solutions of methanol and water, using a chromatographic method. The solubility was evaluated for the entire mole fractions of the binary mixture covering the temperatures from 298.15 K to 323.15 K. The results indicated that the chromatographic method is suitable for determining sugar concentration, but it implies an increased uncertainty over the results. The solubility of both sugars was low in methanol-rich binary mixtures, rising with the increasing proportion of water. Greater dependence of the solubility as a function of the composition of the binary mixture was observed for sucrose, indicating stronger molecular interaction and therefore greater deviation from ideality. The NRTL activity coefficient model and the PC-SAFT and CPA equations of state were successfully employed to correlate the solid-liquid equilibrium. The binary interaction parameters were optimized as a function of temperature. The NRTL model has shown greater deviations than those presented by the equations of state. Meanwhile, the equations of state have presented a similar performance.

APPLICATION OF REFRACTIVE INDEX MIXING PRINCIPLES IN BINARY SYSTEMS AT T=298.15, 308.15 AND 318.15K

Binary liquid mixes of 1-butanol, 1-pentanol, 1-hexanol, and 1-heptanol with hexadecane and heptadecane have had their densities and refractive indices experimentally determined at 298.15, 308.15, and 318.15 K. To determine whether the Lorentz-Lorenz (L-L), Weiner-Heller (W-H), and Gladstone-Dale (G-D) relations for predicting the refractive index of a liquid are valid for the eight binaries over the entire mole fraction range of hexadecane and heptadecane at the three temperatures, a comparative study of these relationships has been conducted. The average percentage deviation has been used to compare different mixing rules. Comparatively speaking, the Weiner and Gladstone-Dale relations perform better than the Lorentz-Lorenz and Heller relations.

Synthesis and physico-chemical characterization of binary mixtures of hydroxyl- and ester-functionalized ionic liquids

The first binary system of 1-(6-hydroxyhexyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (IL-OH) and 1-(hexyl-4-oxopentanoate)-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (IL-Ester) ionic liquids (ILs) was prepared across the entire mole fraction range. Physico-chemical properties such as density, viscosity, thermal stability and refractive index were determined for the binary system at different temperatures. It was found that the density decreases whereas viscosity and refractive index increase as a function of IL-Ester mole fraction. Furthermore, the excess properties (molar volumes, and refractive indices) were calculated which indicated increasing interactions and hence improved packing efficiency by the addition of IL-Ester. The thermal stability was somewhat lowered by the presence of IL-Ester. Hence, this study has provided an insight into the mixing behaviour and interactions among these binary mixtures. A group contribution method was applied to estimate densities from refractive index measurements. Overall, this work forms the basis for developing these types of ionic liquids for reactive extractions of value-added products.

Investigation of molecular interaction, performance of green solvent in esterification of ethanol and acetic acid at 298.15 K and at 1 atm

AbstractIn the present study, the potential of a selective green solvent for the low temperature esterification were analysed. Hence, 1‐ethyl‐3‐methylimidazolium hydrogen sulphate {[EMIM][HSO4]},1‐ethyl‐3‐methylimidazolium ethylsulphate {[EMIM][EtSO4]}, choline chloride glycerol {[ChCl][Gly]} and choline chloride acetic acid {[ChCl][AA]} were chosen as a selective green solvent. Whereas water, ethanol, acetic acid can be treated as molecular solvent used in the esterification process. In this reason, density of eight binary mixtures over the entire mole fractions were measured at different temperature ranges. The results have been used to calculate the excess and derived thermodynamic properties, to measure the strength of molecular interaction between mixing components. Further, the sigma profile and sigma potential plot were generated and analysed. According to density, volumetric properties, molecular polarity results, 1‐ethyl‐3‐methylimidazolium hydrogen sulphate [EMIM][HSO4] was chosen as green solvent for the green esterification process. Finally, [EMIM][HSO4] based low temperature esterification were conducted at 298.15 K and 1 atm. 80.96% of n‐BuAc was achieved.

Thermodynamic properties of binary liquid mixtures of benzyl alcohol with 2-Alkoxyethanols at varying temperatures

In the present research, density (ρ) and speed of sound (u) for binary liquid mixtures of the benzyl alcohol (BA) with three 2-alkoxyalcohols {2-methoxyethanol (2-ME), 2-ethoxyethanol (2-EE), and 2-butoxyethanol (2-BE)} at temperatures of 298.15, 303,15 and 308.15 K have been measured over complete concentration of benzyl alcohol under 0.1 MPa pressure. According to measured results, excess molar volume (VmE) and deviation in isentropic compressibility (Δκs) were computed and these observed results were correlated to Redlich−Kister (R-K) polynomial expansion. Further, molar volume (Vm), apparent molar volumes (Vm,∅,1 and Vm,∅,2), acoustic impedance (Z), isentropic compressibility (ks), intermolecular free length (Lf), deviation in intermolecular free length (ΔLf) were calculated at all worked temperatures. For all studied systems, excess molar volume (VmE) and deviation in isentropic compressibility (Δκs), and deviation in intermolecular free length (ΔLf) were negative over the entire mole fraction range of benzyl alcohol at all measured temperatures. Among the three systems, benzyl alcohol with 2-ethoxyethanol containing system showed more negative. By using the obtained results, intermolecular interactions were discussed between benzyl alcohol and 2-alkoxyethanols. Moreover, the influence of temperature on intermolecular interactions was analyzed using above said parameters.

Role of mixing thermodynamic properties on the Soret effect.

We demonstrate that the modified Kempers model, a recently developed theoretical model for the Soret effect in oxide melts, is applicable for predicting the composition dependence of the Soret coefficient in three binary molecular liquids with negative enthalpies of mixing. We compared the theoretical and experimental values for water/ethanol, water/methanol, water/ethylene glycol, water/acetone, and benzene/n-heptane mixtures. In water/ethanol, water/methanol, and water/ethylene glycol, which have negative enthalpies of mixing across the entire mole fraction range, the modified Kempers model successfully predicts the signchange of the Soret coefficient with high accuracy, whereas, in water/acetone and benzene/n-heptane, which have composition ranges with positive enthalpies of mixing, it cannot predict the signchange of the Soret coefficient. These results suggest that the model is applicable in composition ranges with negative enthalpies of mixing and provides a framework for predicting and understanding the Soret effect from the equilibrium thermodynamic properties of mixing, such as the partial molar volume, partial molar enthalpy of mixing, and chemical potential.

English

Refractive index is a characteristic parameter of fluids with numerous industrial uses. The values of refractive indices of many pure liquids are known or can be found in the literature. However, when experimental values of the liquid mixtures are not available then refractive indices of binary mixtures and multi-component liquids are frequently assessed from the pure constituents using mixing rules. The refractive indices  of binary mixture and pure liquids methyl laurate (M.L) and pentan -2-ol (P) over the entire mole fraction range at five temperatures (298.15, 303.15, 308.15, 313.15, and 318.15K) were measured using an Anton-Paar Abbemat 3200 refractometer and were tested with the traditional equations, viz Gladstone-Dale (G.D), Lorentz-Lorentz (L.L), Weiner-relation (W.R) and Heller-relation (H.R). The excess refractive indices  were calculated using measured experimental refractive indices  and  ideal refractive indices. The values of excess refractive indices were found to be negative at low mole fractions and positive over the high mole fractions. The experimental data for binary mixture involving methyl laurate + Pentan-2-ol authenticate the mixing rules. Key words: Excess refractive index, binary mixture, mixing rules, methyl laurate.

Density and Ultrasonic Study of Benzene Sulphonyl Chloride with Hydrocarbon at 303.15 K.

Experimental values of Ultrasonic velocity and density for the binary mixture of Benzene Sulphonyl Chloride with Hydrocarbons have been measured at 303.15 K over the entire mole fraction range, using these data the excess Adiabatic compressibility (βsE) and excess Free length (Lf E) have been calculated. These parameter were used to study the nature and extent of intermolecular interaction between component molecules, present in binary mixture. excess value of Adiabatic compressibility (βsE), sound velocity (UE ) and free length(Lf E) were plotted against the mole fraction of Benzene Sulphonyl Chloride over the whole composition range the value of βsE, UE, Lf E for these three binary mixture have been found to be negative, the non linear variation of these parameter show the presence of interaction and their excess value is indicative of interaction between the components molecule in all system.

Free Volume and Internal Pressure of Binary Liquid Mixtures from Ultrasonic Velocity at 303.15 K

Ultrasonic velocity (u), density (ρ), and viscosity (η) measurements have been taken in six binary liquid mixtures ethyl acetate + methanol, ethyl acetate + ethanol, ethyl acetate + propanol, ethyl acetate + butanol, ethyl acetate + hexanol and ethyl acetate + octanol at 303.15 K over the entire mole fraction range. The experimental data has been used to calculate the free volume, internal pressure and their excess values. Excess values of free volume〖(V〗_f^E) and internal pressure (p_i^E) were plotted against the mole fraction of ethyl acetate over the whole composition range at 303.15 K. They have been analyzed to discuss the nature and strength of intermolecular interactions in these mixtures.

Excess thermodynamic properties and FTIR studies of binary mixtures of aniline with esters at different temperatures

Densities (ρ) and speeds of sound (u) were measured over the entire mole fraction range for the binary mixtures of aniline with butyl acetate (BA), iso-butyl acetate (IBA), tert-butyl acetate (TBA) and butyl acrylate (BAc) at T = (303.15–318.15) K. These data were used to compute excess molar volume (VmE), excess isentropic compressibility (κSE) and excess speed of sound (uE) for investigating the different types of intermolecular interactions present in the mixtures. These parameters have been correlated with Redlich-Kister equation. Further, the u and VmE values have been analyzed with different theoretical models. The molecular structure and polarity of the ester molecule along with the nature and bulkiness of its alkyl group found to affect the magnitude of investigated excess thermodynamic properties of the binary systems. FTIR spectral analysis of these mixtures was used to understand the interactions between component molecules and to correlate them with the thermodynamic findings.

Experimental measurements and correlations of the vapor phase pvTx behavior of binary mixtures of 1,1,1,2-tetrafluoroethane (R134a) + 2,3,3,3-tetrafluoroprop-1-ene (R1234yf)

In the present study, the accurate determination of the vapor phase pvTx behavior of binary mixtures of 1,1,1,2-Tetrafluoroethane (R134a) + 2,3,3,3-Tetrafluoroprop-1-ene (R1234yf) by using a Burnett apparatus was demonstrated. Measurements have been performed over the temperature range from (303 to 388) K and at pressures up to 5023 kPa covering the mole fractions of xR134a = (0.000, 0.099, 0.328, 0.523, 0.726, 0.919, 1.000). The combined expanded uncertainties of temperature, pressure, mole fraction and vapor density with a level of confidence of 0.95 (k = 2) were estimated to be 24 mK, 1.6 kPa, 0.01 and within 0.2% over the entire temperature, pressure and mole fraction ranges, respectively. In order to facilitate practical industrial applications and explore the thermophysical behavior of the second and third virial coefficients, the experimental vapor density data of this work were used to develop the virial equation of state with the average absolute deviation of compressibility factor lower than 0.52% for each composition. Furthermore, the obtained gaseous pvTx properties of R134a/R1234yf mixtures were compared with the multi-parameter equation of state of REFPROP 10.0 (Lemmon et al., 2018) and the relative deviations were less than 1.2%.

Viscometric Properties of Binary Mixtures of 1,4-Butanediol + Cresols at Different Temperatures

The viscosities of binary mixtures of 1,4-butanediol with o-cresol, m-cresol and p-cresol have been determined at 303.15, 308.15, 313.15 and 318.15 K over the entire mole fraction range. The deviation in viscosity,, and excess Gibbs energy of activation (G*E) of viscous flow have been examined in terms of structural changes and interactions. The deviations/excess values were fitted to the Redlich-Kister equation to determine the fitting parameters and the root-mean square deviations. The results obtained for viscosity of binary mixtures were used to test the semi-empirical relations of Bingham, Frenkel, Kendall, HindUbbelhode, Refutas, Sutherland Wassiljiewa, Gambill, McAllister, Hind, Grunberg, Wijk, McAllister 4 body, Tamura Kurata, Katti-Chaudhri and Nhaesi.

Studies on excess molar volumes and viscosity deviations of binary mixtures of household kerosene and premium motor spirit at 303K

Density and viscosity of binary liquid mixtures of household kerosene (HHK) and premium motor spirit (PMS) were determined over the entire range of mole fraction at 303K. Excess molar volume (VE), molar volume (Vm), Excess Viscosity (ηE), Viscosity deviations (Δη) and excess Gibbs free energies of activation of viscous flow (ΔGE) were calculated. The results obtained shows that excess free energy of activation were all positive over the entire mole fraction. The viscosity deviation shows both negative and positive values. The positive VE obtained in this study shows increase in volume in the binary mixture. This work will help in effective monitoring, detection of adulterated kerosene and subsequent enforcement of severe penalty on such adulteration.

Densities, speeds of sound, refractive indices, excess and partial molar properties of polyethylene glycol 200 + benzyl methacrylate binary mixtures at temperatures from 293.15 to 318.15 K

Green and biodegradable solvents are requisite replacements to volatile organic solvents. Polyethylene glycols have been recognized as alternatives to volatile organic solvents in numerous industrial and pharmaceutical applications because of their unique properties. In this work the measurements of physicochemical properties, viz., densities, ρ, speeds of sound, u and refractive indices, nD of the binary mixtures of PEG 200 with benzyl methacrylate, including pure liquids, over the entire mole fraction range at the temperatures, T/K = 293.15 to 318.15 and at atmospheric pressure, p = 101 kPa. The experimental data were used to calculate the excess molar volume, VmE, excess isentropic compressibility, κsE, excess speed of sound, uE, excess acoustic impedance, ZE, excess molar isentropic compressibility, Ks,mE, excess refractive index, nDE and deviation in molar refraction, ΔRM . These excess properties were fitted with the Redlich-Kister polynomial equation. In addition, the partial molar volumes and partial molar compressibilities and excess partial molar volumes and excess partial molar compressibilities over the entire mole fraction range; and at infinite dilution were also calculated. The trends of these parameters with composition and temperature were discoursed from the point of view of intermolecular interactions existed in these mixtures.

Refractive Indices of Aqueous Solutions of Isomeric Butylamines at 303.15 K: Experimental and Correlative Approach

Refractive indices () and densities (r) of water (W) + n-butylamine (NBA), + sec-butylamine (SBA) and + tert-butylamine (TBA) systems had been measured in the whole range of composition at 303.15 K, from which deviation in refractive index (DnD ) molar refraction (Rm) and excess molar refraction () had been evaluated. All of the derived properties were fitted to appropriate polynomials. DnD were fitted to the Redlich-Kister polynomial equation. Values of DnD were all positive and were all negative which were attributed to cross hydrogen bonding, specific interactions as well as interstitial accommodation effect. A comparative study of Lorentz-Lorenz (L-L), Weiner (W), Heller (H), Gladstone-Dale (G-D), Arago-Biot (A-B), Eykman (Eyk), Newton (Nw), Eyring-John (E-J) and Oster (Os) relations for determining the refractive index of a liquid had been carried out to test their validity for the three binaries over the entire mole fraction range of butylamines at 303.15 K.