Prigogine – Flory – Patterson Research Articles

Thermodynamic properties of binary liquid mixtures containing aromatic alcohol and aliphatic amines at different temperatures

As an extension of our previous work, thermodynamic and acoustic properties of binary mixtures of benzyl alcohol with propyl amine, di-propyl amine, diiso-propyl amine and tri-propyl amine have been investigated by measuring density and speed of sound data at four temperatures (T = 303.15, 308.15, 313.15 and 318.15 K) and pressure (P = 0.1 MPa) over the entire composition range. These data have been utilized to calculate excess parameters like excess molar volume (VmE), excess isentropic compression (KSE ) and excess speed of sound (uE) for all the systems.All the excess parameters have been correlated by Redlich-Kister equation. Further, to analyse the experimental results theoretical treatment of the data has also been done by using Prigogine–Flory–Patterson (PFP) theory, intermolecular free length theory and collision frequency theory. Results were also supported by FTIR studies of equimolar binary liquid mixtures.

Role of chain length in molecular interactions between monoethanolamine and 2-alkoxyalkanols at various temperatures

Abstract Densities (ρ) and speeds of sound (u) were measured for the binary mixtures of monoethanolamine (MEA) with 2-methoxyethanol (ME), 2-ethoxyethanol (EE), 2-propoxyethanol (PE) and 2-butoxyethanol (BE) mixtures at temperatures 303.15, 308.15, 313.15 and 318.15 K over the entire composition range. These data were used to compute the isentropic compressibility (κS), excess molar volume ( V m E ) and excess isentropic compressibility ( κ S E ). The values of V m E were analyzed using Prigogine-Flory-Patterson (PFP) theory. The excess functions were fitted and correlated with Redlich–Kister and Hwang equations. The measured data were discussed in terms of intermolecular interactions between component molecules. The experimental speeds of sound data in the present investigated mixtures were compared with various theoretical models like collision factor theory (CFT) and free length theory (FLT) to check their relative merits of pure component properties. Moreover, the experimental excess functions were correlated in terms of FTIR spectral analysis.

Understanding the peculiar effect of water on the physicochemical properties of choline chloride based deep eutectic solvents theoretically and experimentally

Deep Eutectic Solvents (DES), the novel eco-friendly solvents and are analogous to ionic liquids (IL) are also termed as the new age alternatives to the volatile organic solvents owing to their unique physicochemical properties similar to ILs. Water, either present as an unavoidable impurity or added purposefully to lower the cost and viscosities of DES/ILs have peculiar effect on their physicochemical properties. It is imperative to study the effect of water on these eco-friendly solvents. Herein, we report the experimentally determined densities (ρ) and speeds of sound (u) for aqueous DES solution over the entire range of composition and temperature ranges from 293.15 K to 323.15 K at atmospheric pressure. The equimolar ratio of choline chloride as the hydrogen bond acceptor (HBA) with malonic acid and glutaric acid as the hydrogen bond donors (HBD) was used to prepare the DESs. The dependence of DES and H2O composition, role of HBD and temperature is discussed on the excess molar volumes VmE and excess molar isentropic compressibilities Ks, mE. The negative VmE and Ks, mE indicate the dominance of intermolecular interactions over the intra-molecular interactions. The formation of H-bond between ion-water and HBD-water interactions is also discussed in terms of DES composition and temperature. We have used the Prigogine−Flory−Patterson (PFP) theory and for the first time extended real association model (ERAS) to evaluate the non-ideal behaviour of the studied systems. Results of highly unpredictable, distinct contours excess properties over the entire range of composition of DES could be helpful in designing various industrial processes and for the thermodynamic modeling of DES.

Molecular interaction studies of binary mixture formed by 2-methoxyethanol and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide-based ionic liquid

ABSTRACTPhysicochemical properties such as density (ρ), speed of sound (u) and refractive index (nD) for binary mixture of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide with 2-methoxyethanol (2-ME), have been investigated over the whole composition range at different temperatures (298.15–318.15) K and ambient pressure. Additionally the excess properties such as excess molar volume (), excess molar isentropic compressibility (), excess isobaric thermal expansion coefficient (), deviation in refractive index () and partial molar quantities, have been also evaluated, simultaneously these are fitted with Redlich-Kister type equation for acquiring the binary coefficients and standard deviations. The calculated data has been interpreted in terms of various interactions and structural property between organic and ionic liquid molecules upon mixing. ATR-FTIR studies also carried out to know the microscopic interactions. The experimentally obtained excess molar volumes are further analysed with the help of Prigogine-Flory-Patterson (PFP) theory.

Excess volumes of mixtures consisting of deep eutectic solvents by the Prigogine–Flory–Patterson theory

Deep Eutectic Solvents are complex solvents whose properties are challenging to understand and to model. In this study, the Prigogine–Flory–Patterson (PFP) theory was used, for the first time in literature, to estimate excess molar volumes of different systems consisting of Deep Eutectic Solvents (DESs). Twelve different systems, consisting of Ethaline + DMSO, Ethaline + water, Reline + water, Reline + methanol, Reline + ethanol, Glycine + water, Glycine + methanol, Glycine + ethanol, Glycine + isopropanol, Maline + water, Tegaline + water, and Glucoline + water were investigated in the full range of concentrations and within wide ranges of temperature, at atmospheric pressure. Excess molar volume is a complicated thermodynamic property because it depends not only on the shape, size, and chemical nature of each pure component in the mixture, but also on all of the binary and higher order interactions of the components in the mixture. The Prigogine–Flory–Patterson theory is one of the very few theoretical models for estimating excess molar volume. Because of the thermodynamic background of the PFP theory, which divides the excess molar volume into three different molecular interaction contributions, the results of this model in mixtures involving DESs can be valuable for a rough interpretation of the molecular interactions of such complex mixtures at a microscopic scale. In order to avoid the correlative aspect of the PFP theory, a generalized relation was proposed for the interaction parameter of the theory covering all temperatures. The resulting model, with a total AARD% of 14.6% and agreement between the predicted trends and the corresponding experimental trends, indicated the capability and suitability of the PFP theory in estimating excess molar volumes of such complex and non-ideal mixtures consisting of DESs.

Investigation of molecular interactions in binary mixture of dimethyl carbonate + N-methylformamide at T = (303.15, 308.15, 313.15 and 318.15) K

Density (ρ) and speed of sound (u) of binary liquid mixtures of dimethyl carbonate and N-methylformamide have been determined at T = (303.15, 308.15, 313.15 and 318.15) K over the entire composition range. Experimental data are used to evaluate excess values of molar volume ( $$V_{\text{m}}^{\text{E}}$$ ), isentropic compressibility ( $$k_{\text{s}}^{\text{E}}$$ ), isothermal compressibility ( $$k_{\text{T}}^{\text{E}}$$ ), intermolecular free length ( $$L_{\text{f}}^{\text{E}}$$ ), acoustic impedance ( $$Z^{\text{E}}$$ ) and ultrasonic speed ( $$u^{\text{E}}$$ ). The VE data in the present investigation were analysed by using Prigogine–Flory–Patterson (PFP) theory. Partial and excess partial molar volumes ( $$\bar{V}_{{{\text{m}},1}}$$ , $$\bar{V}_{{{\text{m}},2}}$$ ), ( $$\bar{V}_{{{\text{m}},1}}^{\text{E}}$$ , $$\bar{V}_{{{\text{m}},2}}^{\text{E}}$$ ) and partial and excess partial molar volume of the components at infinite dilution ( $$\overline{V}_{{{\text{m}},1}}^{\infty }$$ , $$\overline{V}_{{{\text{m}},2}}^{\infty }$$ ), ( $$\overline{V}_{{{\text{m}},1}}^{{{\text{E}},\infty }}$$ , $$\overline{V}_{{{\text{m}},2}}^{{{\text{E}},\infty }}$$ ) at T = (303.15, 308.15, 313.15, 318.15) K have been calculated. The excess/deviation properties were fitted to Redlich–Kister equation to obtain their coefficients and standard deviations. The present investigation also comprises the acoustic nonlinearity parameter (B/A) in the mixtures and calculation of cohesive energy $$\Delta A$$ , Van der Wall’s constants (a, b) and distance of closest approach (d). Moreover, various semi-empirical relations of ultrasonic speed have been used to correlate the theoretical velocities. FT-IR spectra of pure components and their binaries have been measured at T = 298.15 K.

Investigation of molecular interactions in binary liquid mixture: Measurements and correlation through thermo physicochemical study

Density (ρ)/acoustic speed (u) of sound have been experimentally measured over the complete mole fraction on (dimethyl carbonate + diisopropyl ether) mixture at T = (308.15/313.15/318.15) K and atmospheric pressure. Investigational data have been used to gauge excess molar volume /partial molar volume/excess partial molar volume/excess values of intermolecular free length/isentropic compressibility/acoustic impedance/isobaric thermal expansion coefficient/isothermal compressibility/surface tension. Extended Langmuir model pertinent to surface tension was applied to check the depth of penetration of molecular interactions between molecules. The excess values were fitted to Redlich-Kister equation and subsequently standard deviations are evaluated from coefficients. The departures of computed excess properties were explored in terms of molecular interactions. Experimental excess molar volume in the existing adventure was correlated by Prigogine–Flory–Patterson (PFP) theory/Soave-Redlich-Kwong (SRK) CEoS/Peng-Robinson (PR) CEoS at 308.15 K. Theoretical excess chemical potentials are computed and correlated by Margules/Porter/Wilson and VanLaar models at 308.15 K. Furthermore, vital thermodynamical potential derivatives are worked out at all temperatures through physicochemical properties rather calorimetric experiments. Contemporary study also consists of estimation and correlation of cohesive energy ΔA, Van der Wall's constants (a, b), distance of closest approach (d) by Hartmann–Balizar and Ballou non-linear equations at all temperatures.

Volumetric, acoustic and optical properties of binary mixtures of 2-propanol with n-alkanes (C6-C10) from 293.15 K to 303.15 K

Densities, ultrasonic speeds and refractive indices of 2-propanol + n-alkanes (C6-C10) systems were experimentally determined at 293.15 K to 303.15 K. Calculated excess molar volume, deviation in ultrasonic speed, refractive index, excess isentropic compressibility and excess intermolecular free length were correlated with Redlich-Kister equation. The excess volume was also interpreted by Flory-Treszczanowicz-Benson (FTB) model and Prigogine-Flory-Patterson (PFP) theory. While the excess molar volume were predicted well with FTB model, PFP theory able to describe sign and magnitude of excess molar volume values in propanol rich region but failed to describe in propanol lean region. For the theoretical estimation of ultrasonic speed and refractive index values, various correlation and mixing rules were also applied.

Influence of temperature on thermo physical properties of binary mixtures of ethyl acrylate and alkyl amines: An experimental and theoretical approach

Densities (ρ) and speed of sound (u) values have been measured for the binary mixtures of ethyl acrylate with propylamine, dipropylamine, diisopropylamine and tripropylamine at four temperatures (T = 303.15, 308.15, 313.15 and 318.15 K) and at atmospheric pressure over the entire composition range. Further, the measured data has been utilized to compute excess molar volume (VmE) and excess isentropic compressibility (κSE) for all the systems under the same experimental conditions. Expansion of our study has been done by calculating other thermodynamic parameters such as excess intermolecular free length (LfE) and excess speed of sound (uE). These calculated excess parameters have been correlated by Redlich-Kister equation. The experimental results have also been analysed by using Prigogine–Flory–Patterson (PFP) theory, intermolecular free length theory and collision frequency theory. To elucidate the presence of intermolecular interactions and structural effects the work has been augmented by FTIR studies also.

Thermodynamic properties of the dodecylbenzenesulfonic acid-acetone binary liquid mixture using a modified flory theory

<p>Prigogine–Flory–Patterson (P-F-P) theory was applied for the correlation the experimental data of excess molar volume for the binary liquid mixture of DBSA-Acetone at the temperature range of (293.15-303.15 K). The three contribution terms (pressure, interaction and free volume) in the P-F-P equation were compared with the total effect of P-F-P equation. A positive excess molar volume were obtained at all the range of mole fraction and at all the temperatures. The maximum value of excess molar volume was positioned at the 0.4 mole fraction. Eyring-Flory-Huggins theory was found useful in the estimation of the viscosity deviation variation with mole fraction at the same temperature range. A negative deviation was found in the viscosity for all the range of temperature and mole fraction. The maximum deviation in the viscosity was found at the mole fraction of 0.4. The increase in the negative deviation values with temperature was interpreted as a result of the decrease in the attractive forces between the like molecules.</p><p>Chemical Engineering Research Bulletin 20(2018) 30-35</p>

Effect of co-solvent and temperature on interactions in 1-ethyl-3-methylimidazolium trifluoromethanesulfonate + ethylene glycol or/and N,N-dimethylformamide, and ethylene glycol + N,N-dimethylformamide mixtures: Measurement of thermophysical properties

The excess molar volumes, VE, excess molar isentropic compressibilities, Κs,mE, viscosity deviations, Δη and Gibbs free energies of activation, ΔG∗ have been determined by using the experimentally measured values of densities, ρ, speeds of sound, u, and viscosities, η of pure 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM][CF3SO3]), ethylene glycol (EG) and N,N-dimethylformamide (DMF) and of binary mixtures [EMIM][CF3SO3] + EG/DMF; EG + DMF in the mole fraction range (x1) from 0 to 1 and of ternary mixture [EMIM][CF3SO3] + DMF + EG in the range of x1 from 0.03 to 0.8 at temperatures, (298.15, 303.15, 308.15, 313.15, 318.15 and 323.15) K and pressure 0.1 MPa. The VE, Κs,mE and Δη values of binary systems have been correlated with Redlich-Kister polynomial equation. The VE, Κs, mE and Δη values of ternary system have been correlated with Cibulka equation. The variations of measured data with composition and temperature are discussed in terms of ion-ion, ion-dipole and dipole-dipole interactions prevailing in the mixtures. We have also applied a number of semiempirical relations for correlation/prediction of our experimental dynamic viscosity data and evaluated some interactional parameters of studied binary mixtures. The excess molar volumes of each binary system have also been correlated to the Prigogine-Flory-Patterson (PFP) theory.

Molecular dynamic simulation, molecular interactions and structural properties of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide + 1-butanol/1-propanol mixtures at (298.15–323.15) K and 0.1 M Pa

The excess molar volumes (VE), excess molar isentropic compressibilities (Κs,mE) and viscosity deviations (Δη) have been evaluated using the experimental densities, ρ, speeds of sound, u and viscosities, η data of pure ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, ([BMIM][NTF2]), 1-butanol, 1-propanol and of their binary mixtures over the entire mole fraction range of ionic liquid at temperatures (298.15, 303.15, 308.15, 313.15, 318.15 and 323.15) K and at 0.1 MPa pressure. The VE, Κs,mE and Δη values have been fitted to Redlich-Kister polynomial equation. The experimental and computed parameters have been discussed in terms of ion-ion, ion-dipole, dipole-dipole and hydrogen bonding interactions. The ρ and VE values have also been predicted using molecular dynamics (MD) simulations, in order to correlate the thermodynamic properties to the microscopic structure of the mixtures analyzing the radial and spatial distribution functions. The Prigogine-Flory-Patterson (PFP) theory has been applied to correlate the excess molar volumes.

The Study of Solute–Solvent Interactions in 1-Butyl-3-Methylimidazolium Hexafluorophosphate + 2-Pyrrolidone from Volumetric, Acoustic, Optical and Spectral Properties

The density (ρ), speed of sound (u) and refractive index (nD) of [Bmim][PF6], 2-pyrrolidone and their binary mixtures were measured over the whole composition range as a function of temperature between (303.15 and 323.15) K at atmospheric pressure. Experimental values were used to calculate the excess molar volumes \( \left( {V_{m}^{\text{E}} } \right) \), excess partial molar volumes \( \left( {\overline{V}_{m}^{\text{E}} } \right) \), partial molar volumes at infinite dilution \( \left( {\overline{V}_{m}^{{{\text{E}},\infty }} } \right) \), excess values of isentropic compressibility \( \left( {\kappa_{S}^{\text{E}} } \right) \), free length \( \left( {L_{\text{f}}^{\text{E}} } \right) \) and speeds of sound \( \left( {u^{\text{E}} } \right) \) for the binary mixtures. The calculated properties are discussed in terms of molecular interactions between the components of the mixtures. The results reveal that interactions between unlike molecules take place, particularly through intermolecular hydrogen bond formation between the C2–H of [Bmim][PF6] and the carbonyl group of pyrrolidin-2-one. An excellent correlation between thermodynamic and IR spectroscopic measurements was observed. The observations were further supported by the Prigogine–Flory–Patterson (PFP) theory of excess molar volume.

Excess Molar Volumes, Excess Molar Isentropic Compressibilities, Viscosity Deviations, and Activation Parameters for 1-Ethyl-3-methyl-imidazolium Trifluoro-methanesulfonate + Dimethyl Sulfoxide and/or Acetonitrile at T = 298.15 to 323.15 K and P = 0.1 MPa

The densities, ρ, speeds of sound, u, and dynamic viscosities, η, of pure 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, ([EMIM][CF3SO3]), dimethyl sulfoxide, (DMSO), acetonitrile, (ACN), and their binary and ternary mixtures have been measured experimentally over the entire composition range and at temperatures of 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15 K and at a pressure of 0.1 MPa. The excess molar volume, VE, excess molar isentropic compressibility, Ks,mE, viscosity deviations, Δη, Gibbs energy of activation, ΔG*, and excess Gibbs energy of activation, ΔG*E have been calculated using the experimental ρ, u, and η values of pure [EMIM][CF3SO3], DMSO, ACN, and their binary/ternary mixtures at the studied temperatures and pressure. The excess/deviations properties for the studied binary/ternary systems have been fitted to Redlich–Kister equation. The variations of these parameters with composition and temperature are discussed in terms of ion–ion, ion–dipole, and dipole–dipole interactions prevailing in these mixtures. The excess molar volumes of each binary system have also been correlated to the Prigogine–Flory–Patterson (PFP) theory. Some semiempirical models for correlation/prediction of experimental dynamic viscosity data for studied binary and VE, Ks,mE, Δη, and ΔG*E for ternary mixtures have been applied.

Thermo-physicochemical investigation of molecular interactions in binary combination (dimethyl carbonate + methyl benzoate)

To probe the nature of interaction and its deeds with temperature in the binary combination (dimethyl carbonate + methyl benzoate), the density (ρ)/speed of sound (u) be established for the total mole fraction array at T = (308.15, 313.15 and 318.15) K and at atmospheric pressure. Sign with magnitude of evaluated excess molar volume ( $$V_{\text{m}}^{\text{E}}$$ ) was inspected and comprehensive analysis elucidated not only pervasiveness of strong molecular interactions between molecules but also its transform with temperature. Additional, strong interactions are properly hold up by partial and excess partial molar volume ( $$\overline{V}_{\text{m}}$$ , $$\overline{V}_{\text{m}}^{\text{E}}$$ , $$\overline{V}_{\text{m}}^{{{\text{E}},\infty }}$$ ). Additionally, relative association (R A ), Lennard-Jones repulsive power (n), excess isentropic compressibility ( $$\kappa_{\text{s}}^{\text{E}}$$ ), partial and their excess partial molar isentropic compressibility ( $$\overline{K}_{\text{m}}$$ , $$\overline{K}_{\text{m}}^{\text{E}}$$ ), excess values of isobaric thermal expansion coefficient ( $$\alpha_{\text{P}}^{\text{E}}$$ ), isothermal compressibility ( $$k_{\text{T}}^{\text{E}}$$ ), intermolecular free length ( $$L_{\text{f}}^{\text{E}}$$ ), acoustic impedance (Z E), ultrasonic speed (u E) were evaluated and confirmed the deductions of $$V_{\text{m}}^{\text{E}}$$ . By Redlich–Kister equation, standard deviations are computed through coefficients for excess parameters. At T = 308.15 K, $$V_{\text{m}}^{\text{E}}$$ is correlated by theories of Prigogine–Flory–Patterson (PFP)/topology/Soave–Redlich–Kwong (SRK)/Peng–Robinson (PR) cubic equation of states; prophesied first-order derivatives of thermodynamic potentials; using semi-empirical equations, excess chemical potential/activity coefficients/theoretical speeds are estimated and correlated. Further, microscopic molecular properties are assessed at all temperatures by Sehgal’s equations on nonlinear relations.

Elucidation of molecular interactions between ionic liquid [Emim][triflate] with 2-methoxyethanol &N-methylpyrrolidone: Experimental and COSMO-RS studies

To progress the understanding of molecular interaction for the binaries of an IL, [Emim][triflate] with 2-methoxyethanol (ME) or N-methylpyrrolidone (NMP), thermo acoustic and volumetric properties such as speeds of sound (u) and densities (ρ) were measured as a function of temperature between (298.15–318.15) K over the entire composition range at ambient pressure. The combined volumetric and quantum-chemical (COSMO-RS) calculations have been utilized. These excess properties were fitted to Redlich-Kister type equation for acquiring the binary coefficients and standard deviations. Simultaneously, the COSMO-RS studies exhibited qualitative analysis of ion-pair formation, interactions of ion–dipole and hydrogen bonding between IL with the studied molecular solvents. The experimentally obtained excess molar volumes are further analyzed with the help of Prigogine–Flory–Patterson (PFP) theory.

Exploring molecular interactions of binary mixture (dimethyl carbonate + benzyl benzoate): Measurements and correlation

To explore the type of interaction and its behavior with temperature in the binary mixture (dimethyl carbonate+benzyl benzoate), the density (ρ) and speed of sound (u) are measured for the whole mole fraction range at various temperatures T=(308.15, 313.15 and 318.15) K and at atmospheric pressure. Sign with magnitude of computed excess molar volume (VmE) was examined and detailed analysis elucidated not only prevalence of strong molecular interactions between molecules in study but also its variation with temperature. Further, strong interactions are well supported by partial and their excess partial molar volume (V¯m,V¯mE,V¯mE,∞). Furthermore, relative association (RA), Lennard-Jones repulsive power (n), excess isentropic compressibility (κsE), partial and their excess partial molar isentropic compressibility(K¯m, K¯mE), excess values of isobaric thermal expansion coefficient (αPE), isentropic compressibility (κsE), isothermal compressibility (kTE), intermolecular free length (LfE), acoustic impedance (ZE), surface tension (σSE), ultrasonic speed (uE) were evaluated and confirmed the conclusions made for VmE. By Redlich-Kister equation, coefficients with standard deviations are computed to excess parameters. VmE is correlated by Prigogine–Flory–Patterson (PFP) and Topology theories at 308.15K. Extended Langmuir model is examined for influence of the bulk mole fraction on surface tension. At T=308.15K, different derivatives of thermodynamic potentials, densities through Soave-Redlich-Kwong (SRK)/Peng-Robinson (PR) cubic equation of states, excess chemical potential and theoretical speeds using semi-empirical equations are evaluated. Using Hartmann–Balizar and Ballou non-linear equations, cohesive energy (ΔA), van der Wall's constants (a, b), distance of closest approach (d) are estimated through Sehgal's equations at all temperatures.

Excess Molar Enthalpies for Binary and Ternary Mixtures Containing Cyclic Ethers, Lactam and Cyclic Ketones

Excess molar enthalpies $$ H_{{}}^{\text{E}} $$ for binary 1,3-dioxolane (1) + 1,4-dioxane (2) or N-methylpyrrolidin-2-one (2) + cyclohexanone or cycloheptanone (3) and $$ H_{123}^{\text{E}} $$ for ternary 1,3-dioxolane (1) + N-methylpyrrolidin-2-one or 1,4-dioxane (2) + cyclohexanone or cycloheptanone (3) mixtures have been measured over the entire mole fraction range at 308.15 K and atmospheric pressure using a micro differential calorimeter (Model-l DSC 7 Evo). The $$ H_{{}}^{\text{E}} $$ and $$ H_{123}^{\text{E}} $$ data have been correlated with composition by fitting of the corresponding data to the Redlich–Kister equation. The topology of the constituent molecules (Graph theory) has been utilized to predict $$ H_{123}^{\text{E}} $$ values of the present mixtures. It is observed that the $$ H_{123}^{\text{E}} $$ values calculated by Graph theory compare well with their corresponding experimental values. The $$ H_{123}^{\text{E}} $$ data have also been tested in terms of the Prigogine–Flory–Patterson (PFP) theory.

Investigation of solute-solvent interactions in {1-butyl-3-methyl imidazoliumBis(trifluoromethylsulfonyl)imide + dimethylcarbonate} mixture using physicochemical properties

Physical properties, such as density (ρ), speed of sound (u) and refractive index of [Bmim][NTf2], DMC and their binary mixtures are measured over the whole composition range as a function of temperature between (303.15 and 323.15) K at atmospheric pressure. Experimental values are used to calculate excess values of molar volumes (VmE)/partial molar volumes (V‾mE)/partial molar volumes at infinite dilution (V‾mE,∞)/isentropic compressibility (κsE)/free length (LfE), speed of sound (uE) and isobaric thermal expansion coefficient (αPE) for the binary mixture. These excess properties are fitted to the Redlich-Kister equation to obtain the binary coefficients and the standard deviations. A qualitative analysis of these parameters indicates strong intermolecular interactions and the interaction increases with the increase in temperature. Further, through physicochemical properties, an attempt for calorimetric excess chemical potential using different equations is computed at T=308.15K. The present investigation also comprises of evaluation of the acoustic non-linearity parameter (B/A) in the mixtures and calculation of cohesive energy (ΔA), Van der Wall’s constants (a, b), distance of closest approach (d). The presence of strong interactions is further supported by IR spectroscopy and the Prigogine–Flory–Patterson (PFP) theory.

Volumetric and optical properties of sulfolane (TMS) + 1, 5-pentanediol binary solutions

The experimental densities of sulfolane (TMS)+1, 5-pentanediol at 293.15–313.15K and refractive index at 298.15–308.15K were reported and expressed by mole fraction of 1, 5-pentanediol. The experimental data of density were used to calculate the excess molar volume, partial molar volume, excess partial molar volume, apparent molar volume, partial molar volumes at infinite dilution, apparent molar volumes at infinite dilution, coefficient of thermal expansion, and excess coefficient of thermal expansion. The deviations in refractive index data were calculated by the Reis equation. Also, the deviations in refractive index and the excess molar volume were fitted using the Redlich-Kister polynomial equation to derive the binary adjustable parameters and standard errors. To probe the interactions and to correlate the excess molar volumes of the examined mixtures, the Prigogine−Flory−Patterson (PFP) theory has been used. The experimental values of refractive indices were examined with two semi-empirical equations of Heller and Edward models. To evaluate the validity of the proposed equations, comparisons were made among the experimental and predicted data. The results are discussed in terms of the intermolecular interactions.