Excess Thermo-acoustic Parameters Research Articles

Comparative Study of Molecular Interaction in Ternary Liquid Mixtures of Polar and Non-Polar Solvents

Ultrasonic velocity measurements, density measurements, and viscometric studies were conducted for the ternary mixture of pyridine and toluene separately with N, N-dimethylformamide (DMF) in butanol, at different temperatures and for different concentrations of component liquids. Using these basic experimental data, various acoustic and thermodynamic parameters, such as adiabatic compressibility (β), free length (Lf,), free volume (Vf), etc. were calculated. Also, Excess thermo-acoustical parameters were calculated from the experimentally measured data. The outcomes were expressed in terms of the molecular interactions and the variations in parameters under varying solute concentrations. A comparative study is discussed. Variation in the above parameters for the different mixtures is indicative of the nature of the interactions between the components in the liquid mixture. Concluding remarks regarding intermolecular interactions are provided.

Experimental and DFT investigation on the role of aromaticity on the stability of hydrogen bonded complexes of cyclohexanone with amines and hydroxyl compounds

The existence of intermolecular hydrogen bonded interaction between four structurally hydroxyl and amino compounds namely, phenol (PHE), aniline (ANI), cyclohexanol (CHL) and cyclohexylamine (CHA) with cyclohexanone (CHE) was investigated in n-hexane medium at 303 K by experimental methods (ultrasonic, UV–Visible, IR spectral analysis) and theoretical (DFT, NCI) methods. From the acoustical and excess thermo-acoustical parameters, strong solute–solute interactions of hydrogen bonded type between the solutes were established. The formation of 1:1complexes between cyclohexanone and hydroxyl, amino compounds was confirmed by UV–visible spectral method and the presence of hydrogen bonding in these complexes was proved by IR spectrum. The stability constant of the four hydrogen bonded complexes was calculated by both ultrasonic and UV–Visible spectroscopic methods. Interestingly, it was found that the order of strength of hydrogen bonding between CHE and hydroxyl as well as amino compounds is in the order CHE-PHE > CHE-ANI > CHE-CHL > CHE-CHA. DFT calculations, NBO analysis and NCI plots were also made to quantify the nature of stabilizing interactions between CHE and hydroxyl and amino compounds. Our computed results are in good agreement with the experimental observations. It is observed that aromatic moiety adjacent to hydrogen donor influences significantly the stability of the H-bonded complexes.

Unravelling the non-covalent interactions in certain n-propyl amine – Ether systems through acoustic and DFT studies at 303.15 K

Ultrasonic study of four binary liquid mixtures, containing n-propyl amine (NPA) as the common component and four structurally different ethers [tetrahydrofuran (THF), 1, 4 dioxane (DIOX), anisole (ANI) and diphenyl ether (DPE)] as varying components is carried out over the entire mole fraction range at 303.15 K and at experimental pressure of 101 kPa. The acoustical and excess thermo acoustic parameters reveal the existence of H-bonded interactions in the four systems and the influence of non-covalent interactions on the constitutional arrangement of ether molecules. It is found that the H-bonded interactions with NPA are stronger in aromatic ethers (ANI, DPE) systems than those in alicyclic ethers systems (THF, DIOX), presented in the manuscript. The optimized molecular geometries of dimers of pure components and the amine-ether complexes are obtained through Density Functional Theory (DFT) method. The values of dipole moments and interaction energies reveal that the stabilization arises due to C-H---π, C-H---O and C-H---N non-covalent interactions (NCI) besides the classical N-H---O H-bonding. The independent gradient model (IGM) analysis of the four systems shows structural dependent on the strength of the interactions. δginter descriptors obtained from pro-molecular IGM method presented against sign(λ2)ρ show the variation of interaction energies of complexes of NPA with structure of ethers.

Computational and experimental study of molecular interaction in a ternary liquid mixture of cyclohexylamine+ethanol+benzene

In the present investigation, we undertake the study of molecular interaction in a ternary mixture of cyclohexylamine (CHA), ethanol (Eth) and benzene (B) theoretically as well as experimentally. We study the interaction between CHA dimer and complexes (Eth-CHA, B-CHA, CHA-Eth-B) theoretically using DFT (Density functional theory) with B3LYP/6-311++G(d,p) level theory in a gas phase. It includes the quantum chemical calculations of interaction energy, bond length, and identification of the intermolecular interaction from structural parameter analysis. Further, we experimentally determine the excess thermo-acoustic parameters of the mixture. For this, we have measured the ultrasonic velocity (u) and density (ρ) of the ternary mixture of cyclohexylamine+ethanol+benzene and of pure components at 303, 308 and 313 K temperature. From these experimental values of u and ρ, excess thermo-acoustic parameters have been estimated using standard relation. The variations in excess acoustic parameters with the concentration of cyclohexylamine (x 1 ) are discussed in terms of the interactions and molecular geometry of the liquid mixture. At lower concentration, weak interactions dominate while on increasing x 1 strong forces between molecules take place. The strong H-bonding interaction between CHA- ethanol molecules and molar volume differences of pure components leads to interstitial accommodation of molecules. Experimentally determined excess properties behaviour is supported by the theoretical calculation.

Study of molecular interaction in a ternary liquid mixture of n-hexane, ethanol and benzene

An extensive theoretical study on the molecular structure of benzene, ethanol, and n-hexane monomer; their dimers and complexes were undertaken using Density Functional Theory (DFT) method. The possibility of the formation of molecular interaction was identified from structural parameter analysis and confirmed with interaction energy calculation. The information about molecular interaction was also assessed by analyzing the excess acoustic parameters. The excess thermo-acoustic parameters have been estimated from the experimentally measured ultrasonic velocity (u) and density (ρ) of the ternary mixture of n-hexane + ethanol + benzene as well as of pure components at (303, 308, 313 & 318) K using standard relation.

Study of acoustical excess parameters and Redlich-Kister coefficients analysis in functional materials

The present research work is related to the analysis involved in the study of excess acoustical parameters and their Redlich-Kister Coefficients at different temperatures range from 303.15 K to 318.15 K with variation of 5 K temperature interval for each study and all these are explained in liquid mixtures containing functional materials namely (Benzene mixed with 1-Propanol). The obtained excess values of acoustical parameters namely Gibb’s free energy (G*E), enthalpy (HE) and internal pressure (πE) have been computed from measured experimental data. The results have also been helpful to obtain Redlich-Kister coefficients from polynomial equation and also to obtain their deviations. Excess thermo-acoustical parameters are discussed along with Redlich-Kister coefficients generally for the study of interactions among the molecules of liquid species.

Analytical study of thermo acoustical excess parameters and Redlich-Kister coefficients in functional materials at known four temperatures range from 303.15 K to 318.15 K

The Analysis of the present work is related to study involved in investigation of excess thermal acoustic parameters and their Redlich Kister Coefficients at different temperatures and all these are analyzed in liquid mixtures containing three functional material combinations namely (Aniline mixed with Toluene), (Aniline mixed with o-Xylene) and (Aniline mixed with Mesitylene). The obtained excess values of acoustical parameters namely Gibb’s free energy (G*E) , enthalpy (HE) and internal pressure (πE) have been computed from measured experimental data . The results have also been helpful to obtain Redlich-Kister coefficients from polynomial equation and also to obtain their deviations. Excess thermo-acoustical parameters are discussed along with Redlich-Kister coefficients generally for the study of interactions among the molecules of liquid species and they are analyzed at known temperatures range from 303.15 K to 318.15 K with variation of 5 K temperature interval for each study.

STUDY OF INTERMOLECULAR INTERACTIONS THROUGH EXCESS THERMOACOUSTIC PARAMETERS IN BINARY MIXTURES OF PROPYLENE GLYCOL AND HEXANOL FOR HEAT TRANSFER APPLICATIONS

Ponte Academic JournalMay 2020, Volume 76, Issue 5 STUDY OF INTERMOLECULAR INTERACTIONS THROUGH EXCESS THERMOACOUSTIC PARAMETERS IN BINARY MIXTURES OF PROPYLENE GLYCOL AND HEXANOL FOR HEAT TRANSFER APPLICATIONSAuthor(s): K. Srisanthi ,Sk. Suriya Shibab, S. Sreehari SastryJ. Ponte - May 2020 - Volume 76 - Issue 5 doi: 10.21506/j.ponte.2020.5.4 Abstract:The investigation on relative strength and the nature of the intermolecular interaction have been done using Ultrasonic method. In our study Density, viscosity, Ultrasonic sound velocities are estimated, further thermo acoustical parameters and their excess values such as, excess adiabatic compressibility (KsE), excess intermolecular free length (LfE),excess free volume (VfE), excess Gibb’s free energy (GE), excess enthalpy (HE) and excess internal pressure (πE) have been measured for propylene glycol in Hexanol for various mole fractions. These results have been explained on the basis of intermolecular interactions between the components in the liquid mixture and correlations among the parameters are discussed. The study indicated that intermolecular hydrogen bond formation is stronger for (0.8 PG+0.2 Hexanol) molar ratio of the binary mixture liquid complex compare to that of other concentrations and hence this mixture is strongly recommended in therapeutical drugs, pharmaceutical industry and for the high heat transferability applications. Download full text:Check if you have access through your login credentials or your institution Username Password

Ultrasonic Study of Effect of Temperature and Concentration on Molecular Interaction in Ternary Liquid Mixture (Propylene Glycol + Benzene + Ethanol)

Ultrasonic velocity, density and viscosity in the ternary mixture of propylene glycol, benzene and ethanol have been measured at 303, 308, 313 and 318 K and 2 MHz. The values of excess thermo-acoustic parameters uE, ηE, Ks E , Lf E , Vm E, ZE; and the Lennard-Jones potential repulsive term exponent (n) have been calculated by using the values of measured parameters. The variation in values and signs of excess parameters with increase in concentration of propylene glycol and temperature is explained by the mechanism of changing the nature of molecular interactions between unlike molecules. Further, the experimental ultrasonic velocities are compared with theoretical values calculated by using various theories like Nomoto′s relation (NR), Schaaffs′s collision factor theory (CFT) and Jacobson′s free length theory (FLT). The relative applicability of these theories is discussed in terms of average percentage errors (APE). The average percentage errors follows the order CFT < NR < FLT at each temperature.

Ultrasonic and DFT studies of aliphatic amine – Cyclic ether interactions in n-hexane solvent at 303.15K

The structure breaking behavior in n-propyl amine (NPA) and formation of hydrogen bonded complexes between NPA and two industrially important cyclic ethers, tetrahydrofuran (THF) and 1,4 dioxane (DIOX) are analyzed through ultrasonic velocity (u), density (ρ) and viscosity (η) measurements in n – hexane medium at 303.15 K and at atmospheric pressure. Various acoustical and excess thermo-acoustical parameters are computed and their variations with concentration confirmed the presence of relatively strong intermolecular interactions between amine and ether molecules. Stability constants (K) of these complexes are determined by ultrasonic method to assess the strength of the interactions. Extensive DFT analysis is carried out on the optimized geometry of the component molecules and also their complexes in n-hexane. Computed hydrogen bond parameters support the observations made in experimental ultrasonic investigations. NCI and RDG plots for the complexes are discussed in the light of possible non covalent interactions.

Structural effect on the strength of non-covalent interactions in binary mixtures of benzyl amine and certain ethers through ultrasonic, FT-IR spectral and DFT studies at 303.15 K

Ultrasonic velocities (u), densities (ρ) and viscosities (η) of four binary liquid mixtures, containing benzyl amine (BA) as common component and four structurally different ethers (tetrahydrofuran (THF), 1,4 dioxane (DIOX), anisole (ANI) and diphenyl ether (DPE)) as varying components, were measured over the entire mole fraction range at 303.15 K and at experimental pressure of 101 kPa. The experimental data were used to compute several acoustical and excess thermodynamic parameters. The computed excess thermo-acoustic properties for each binary mixture are fitted to Redlich–Kister type polynomial equation. The computed binary co-efficients and standard deviations between the experimental and theoretical values established the existence of specific interactions in the complexes of four systems. The acoustical and excess thermo acoustic parameters were analysed in light of various types of intermolecular interactions and their structural dependence. The influence of structures of ethers on the non-covalent molecular interactions has been attempted through Density Functional Theory (DFT) calculation. The optimized structures of the monomers (BA, THF DIOX, ANI, and DPE), their self associated dimers (BA-BA, THF-THF, DIOX-DIOX, ANI-ANI and DPE-DPE) and their complexes with BA confirm the presence of hydrogen bonded interactions in all the four systems. In addition to the classical hydrogen bonding, CH⋯π interactions have also been identified in the binary systems which influenced the interaction energies of the complexes. The presence of non-covalent interactions among the solute species is supported by FTIR spectra of pure compounds and binary mixtures. The shift in the frequencies of the functional groups of amine and ethers has confirmed the observations made through ultrasonic and DFT studies.

Unravelling various types of non-covalent interactions of benzyl amine with ethers in n – hexane at 303.15K by ultrasonic and DFT methods

Physicochemical behaviour of n – hexane solutions containing benzyl amine (BA) and alicyclic ethers in the concentration range 0.02M–0.20 M is extensively studied through acoustical (experimental) and Density Functional Theory (DFT) methods and the nature of non-covalent molecular interactions existing in these ternary liquid mixtures have been investigated. Two structurally different ethers, namely, tetrahydrofuran (THF) and 1,4-dioxane (DIOX) are used. Ultrasonic velocity (u) at 2 MHz frequency, density (ρ) and viscosity (η) are measured for the ternary liquid systems at different concentrations andat 303.15 K. The existence of strong BA – ether non-covalent interaction and formation of hydrogen bonded complexes is identified in both the systems through the variations in acoustical and excess thermo-acoustical parameters with concentration. The influence of structure of ether on the strength of molecular interaction has been analysed through the calculation of formation constants of these complexes computed using Kannappan equation. An attempt has been made using meta hybrid density functional theory to confirm the existence of hydrogen bonded complexes in these two systems through the computed interaction energies and hydrogen bonding parameters. Computational investigation shows CH---π dispersive interactions in these complexes in addition to the classical hydrogen bonding.

Understanding the behavior of binary system contains N, N-dimethylformamide and N-methylanlinine in terms of thermo-acoustic parameters at different temperatures

Thermodynamic elementary parameters such asdensity (ρ), viscosity (η), and speed of sound(U) values of the binary mixture system containsN,N-Dimethylformamide (DMF) with N-Methylaniline (NMA)and for pure liquids were calibrated over the whole combinations at different temperatures (303.15, 308.15 and 313.15) K. From these experimentaldata, various excess thermo-acoustic parameters such as excess isentropic compressibility (KsE), excess molar volume (VE) and excess free length (LfE), excess Gibb’s free energy (ΔG*E), and excess enthalpy (HE) have been calculated. The variations of these properties with composition for these binary mixtures suggest loss of dipolar association, difference in size and shape of the component molecules, dipole-dipole interactions and hydrogen bonding between unlike molecules. The excess parameters have been fitted to the Redlich-Kister polynomial equation using multi-parametric linear regression analysis to derive the binary coefficients and to estimate the standard deviation. Experimental ultrasonic velocities were correlated with various theories such as Nomoto’s relation (UNOM), Junjie’s method (UJM), Impedance relation(UIMP) and Free length theory (UFLT) at all temperatures.

Excess thermodynamic and acoustic properties for equimolar mixtures of benzyl benzoate with 1-butanol at different temperatures

Density (), viscosity () and speed of sound (U) values for the liquid mixture of benzylbenzoate with 1-butanol including those of pure liquids were measured over the entire mole fraction range at T= 303.15 K, 308.15 K and 313.15 K. From these experimentally determined values, various thermo-acoustic parameters such as excess isentropic compressibility (KsE), excess molar volume (VE) and excess free length (LfE), excess gibb’s free energy (G∗E) and excess enthalpy (HE) have been calculated. The excess functions of excess molar volume (VE) and excess free length (LfE) have been fitted to the Redlich–Kister type polynomial equation. The deviations for excess thermo-acoustic parameters have been explained on the basis of the intermolecular interactions.

Study of molecular interactions using excess thermo-acoustical parameters at different temperatures

Ultrasonic velocities, densities and viscosities have been measured in two binary liquid mixtures of quinoline with alkanols (ethanol and 1-propanol) over the entire molefraction range of quinoline at temperatures T=(303.15, 308.15, 313.15 and 318.15)K. From the experimentally measured data, excess thermo-acoustical parameters such as excess intermolecular freelength (LfE), excess adiabatic compressibility (βE), excess free volume (VfE), excess internal pressure (πE),excess enthalpy (HE) and excess Gibb's free energy of activation function (G⁎E) have been calculated. These results are fitted to the Redlich-Kister polynomial equation and have been explained on the basis of intermolecular interactions present between the component molecules of the liquid mixtures.

Application of ultrasound in assessing strength of molecular non-covalent interactions in ternary liquid mixtures

The existence of non-covalent interactions between iodine and three haloarenes, namely, fluorobenzene (FB), bromobenzene (BB) and iodobenzene (IB) with iodine in n-hexane medium at 303K was established from the trend in acoustical properties and excess thermo acoustical parameters with concentration. Formation constants of the three ternary mixtures were determined by a novel ultrasonic method employing the equation proposed by Kannappan. The trend in K values of the three complexes agreed well with the trend obtained by spectral methods by earlier workers. Dispersion and long-range corrected ω-B97X-D3 functional was used to calculate the both π and halogen bonded types of interactions. NBO analyses were used to quantify the nature of the stabilizing interactions that exist in the complexes of haloarenes with I2. Our computed results are in good agreement with the observations in ultrasonic method.

Ultrasonic and spectral studies on charge transfer complexes of anisole and certain aromatic amines

Stability constants of two complexes of anisole with aniline and N-methylaniline (NMA) are determined from the measured ultrasonic velocity in n-hexane medium at four different temperatures. Acoustic and excess thermo acoustic parameters [excess ultrasonic velocity (uE), excess molar volume (VE), excess internal pressure (πiE)] are reported for these systems at four different temperatures. The trend in acoustic and excess parameters with concentration in the two systems establishes the formation of hydrogen bonded complexes between anisole and the two amines. Thermodynamic properties are computed for the two complexes from the variation in K with temperature. The formation of these complexes is also established by UV spectral method and their spectral characteristics and stability constants are determined. K values of these complexes obtained by ultrasonic and UV spectroscopic techniques agree well. Aniline forms more stable complex than N-methylaniline with anisole in n-hexane medium.

Excess thermo-acoustical parameters in binary liquid mixture containing n-butanol at different temperatures

Excess thermo acoustical parameters have been calculated from the experimentally measured data of ultrasonic velocity, viscosity and density in binary liquid mixtures containing n-butanol at different temperatures. These results are fitted to the Redlich–Kister polynomial equation. These results have been explained on the basis of the intermolecular interactions present in the liquid mixtures.

Molecular interaction studies in ternary liquid mixture of dimethylacetamide using ultrasonic technique at 308 K

The experimental density (ρ) and ultrasonic velocity (U) for ternary mixture containing dimethylacetamide (DMAC), acetone and diethyl ether at frequencies 2, 4, 6 and 8 MHz have been measured at temperature 308 K. These data are used to compute adiabatic compressibility (Ks), intermolecular free length (Lf), acoustic Impedance (Z), molar volume (Vm), molar sound velocity (R), molar compressibility (B), available volume (Va), Lennard-Jones potential repulsive term exponent (n), relative association (RA), interaction parameter (χ) and some excess thermo acoustic parameters for whole range of concentration of DMAC and are interpreted to elucidate molecular interaction occurring in the liquid mixture.

Excess parameters for binary mixtures of alkyl benzoates with 2-propanol at different temperatures

Density (ρ), viscosity (η), and speed of sound (U) values for the binary mixture systems of methyl benzoate + 2-propanol and ethyl benzoate + 2-propanol including those of pure liquids were measured over the entire mole fraction range at five different temperatures (303.15, 308.15, 313.15, 318.15, and 323.15) K. From these experimentally determined values, various thermo-acoustic parameters such as excess isentropic compressibility $$ \left( {K_{\text{s}}^{\text{E}} } \right) $$ , excess molar volume (V E) and excess free length $$ \left( {L_{\text{f}}^{\text{E}} } \right) $$ , excess Gibb’s free energy (ΔG *E), and excess enthalpy (H E) have been calculated. The excess functions have been fitted to the Redlich–Kister type polynomial equation. The deviations for excess thermo-acoustic parameters have been explained on the basis of the intermolecular interactions present in these binary mixtures. The theoretical values of speed of sound in the mixtures have been evaluated using various theories and have been compared with experimentally determined speed of sound values in order to check the applicability of such theories to the liquid mixture systems under study. Viscosity data have been used to test the applicability of standard viscosity models of Grunberg–Nissan, Hind–Mc Laughlin, Katti–Chaudhary, Heric and Brewer, Frenkel, Tamura and Kurata at various temperatures for the binary liquid systems under study.