H-NMR Spectral and Dielectric Behaviours of the 2-Metoxyethanol-Tetrahydrofuran Solvent System

Abstract

Relative permittivities (E ₁₂) have been measured for 2-metoxyethanol (ME)-tetrahydrofuran (THF) binary liquid mixtures over the whole compositions range at various temperatures ranging from 291.15 K to 308.15 K. The experimental data were used to test some empirical equations of the type: y ₁₂ = y ₁₂(t) and y ₁₂ = y ₁₂ (X ₁) [where: y ₁₂-E ₁₂]. From all these data, the temperature coefficients of relative permittivities (α₁₂) and the excess extrathermodynamic parameters ε^E were calculated. The ¹H-NMR spectra of liquid binary mixtures of ME and THF, were recorded at 298 K over almost the whole range of the mixed solvent compositions. From these data the values of the values of the spectral structural parameters were found, δδ(ME-THF). These structural parameters as a function concentration suggest the formation of stable 3ME.THF types intermolecular complexes.     

Physicochemical Properties of Acetonitrile-Butan-1-Ol and Acetonitrile-Butan-2-Ol Mixtures

Abstract

The densities (d₁₂ ) and relative permittivities (?¹²) of liquid binary mixtures of acetonitrile-butan-l-ol and acetonitrile-butan-2-ol were measured at 288.15 K, 293.15 K, 298.15 K, 303.15 K and 308.15 K, as well as refractive indices (n ^D ₁₂) at 298.15 K and surface tensions (σ₁₂) at 293.15 K, 298.15 K and 303.15 K. From all these data, the molar volumes (V _m ), apparent molar volumes (V _{i, φ}), temperature coefficients of relative permittivities (α₁₂) and surface tensions (k) and their deviations from ideality were calculated. Additionally, the Kirkwood's correlation factors (g _K ) were found. The values of these properties are discussed in terms of interactions of acetonitrile with butan-1-ol and butan-2-ol.     

Studies on Associated Solutions. Part II. Physicochemical Properties of Acetonitrile-Propan-2-ol Mixtures

Abstract

The ¹H-NMR spectra of liquid binary mixtures of acetonitrile and propan-2-ol, were recorded at 298 K over almost the whole range of the mixed solvent compositions. From these data were found the values of the spectral parameter, Δδ(ACN-PrOH-2). The densities (d ₁₂) and relative permittivities (?₁₂) of the mixed solvent were measured at 288.15K, 293.15K, 298.15K, 303.15K and 308.15K, as well as refractive indices at 298.15K. From all these data, the molar volumes (V _m), temperature coefficients of relative permittivities (α_n) and their deviations from ideality were calculated. Additionally, the Kirkwood's correlation factors (g _K) were found. The values of these properties are discussed in terms of interactions of acetonitrile with propan-2-ol.     

2-Methoxyethanol–Tetrahydrofuran–Binary Liquid System. Viscosities,densities, excess molar volumes and excess Gibbs activation energies of viscous flow at various temperatures

Densities (d ₁₂) and viscosities (η₁₂) have been measured for 2-methoxyethanol (ME) with tetrahydrofuran (THF) binary liquid mixtures over the whole composition range at various temperatures ranging from 291.15 to 308.15 K. The experimental data were used to test some empirical equations of the type: y ₁₂=y ₁₂(t) and y ₁₂=y ₁₂(X ₁) [where: y ₁₂−d ₁₂ or η₁₂]. From all these data, the excess molar volumes (V ₁₂ ^E), the excess viscosities (η₁₂ ^E) and excess Gibbs activation energies (ΔG ^*) of viscous flow were calculated. These structural parameters as a function of concentration suggest the formation of 3ME⋅THF and 2ME⋅THF types of intermolecular complexes. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermodynamic Investigation of Dimethyl Sulfoxide Binary Mixtures at 293.15 and 313.15 K

Densities (ρ), speeds of sound (u), and isentropic compressibilities (k _S) of binary mixtures of dimethyl sulfoxide (DMSO) with water, methanol, ethanol, 1-propanol, 2-propanol, acetone and cyclohexanone have been measured over the entire composition range at 293.15 and 313.15 K. The excess molar volumes (V ^E), the deviations in speed of sound (u ^E) and the deviations in isentropic compressibility (k _S ^E) have been determined. The V ^E, u ^E and k _S ^E values were fitted by the Redlich-Kister polynomial equation and the A _k coefficients as well as the standard deviations (d) between the calculated and experimental values have been derived. The results obtained are discussed from the viewpoint of the existence of interactions between the components of the binary mixtures.     

Densities and Viscosities for the Binary Mixtures (2-Methyl-1-Chloropropane + Isomeric Butanol) at 298.15 and 313.15 K

Abstract

This paper reports excess volumes, V^E , and viscosity deviations, Δ\eta, for binary mixtures of 2-methyl-1-chloropropane with an isomer of butanol at the temperatures 298.15 K and 313.15 K. These properties were obtained from density and viscosity measurements. The results are correlated by means of a Redlich-Kister type equation, and interpreted in terms of molecular interactions. The systems show positive values of V^E except in a short range of compositions for mixtures containing primary butanols (1-butanol at both temperatures and 2-methyl-1-propanol at 298.15 K), whereas Δ\eta presents negative values at both temperatures over the whole composition range.     

Prediction of Heat of Mixing from Internal Pressure Data

Abstract

Excess enthalpies (H^E _m) and excess heat capacities (C^E _p) of three binary liquid mixtures comprising dimethylformamide, acetonitrile and benzene have been evaluated from internal pressure data obtained from three different approaches. The results obtained have been compared with the experimental H^E _m and C^E _p values determined by Miyanaga et al. [1]. H^E _m values evaluated through density, viscosity and ultrasonic velocity data [2] show anomalous behaviour. A critical review has been given.     

Dielectric properties of binary mixtures of n-methylbenzenesulfonamide

The dielectric permittivities of binary mixtures of N-methylbenzenesul-fonamide (N-MBS) with benzyl alcohol, 1,2-dichloroethane, 1,4-dioxane and hexamethylphosphortriamide were measured as a function of mole fraction over the whole composition range at 30 and 50°C. The excess dielectric permittivities and the excess molar polarizations were also calculated. The excess dielectric permittivities ^E and excess molar polarizations P_E were found to be negative for N-methylbenzene-sulfonamide mixtures with benzyl alcohol and 1,4-dioxane, ^E values were positive and P^E values negative for mixtures with 1,2-dichloroethane, and ^E and P^E values were clearly positive for mixtures with hexamethylphosphortriamide. The results are discussed in terms of the strength of the dipolar and hydrogen-bonding interactions between the molecules in various binary mixtures.     

Topological investigations of binary and ternary mixtures: excess isentropic compressibilities

The speed of sound, U_ij 1,3-dioxolane (D) in binary mixtures (ij) with benzene, cyclohexane, n-hexane or n-heptane and U_ijk for 1,3-dioxolane in ternary mixtures (ijk) with the same hydrocarbons have been measured as a function of composition at 298.15 K. The observed data have been utilised to evaluate excess isentropic compressibility of binary, (κ_s^E)_ij and ternary (κ_s^E)_ijk mixtures using density and speed of sound values of the binary and ternary mixtures. The Moelyn-Huggins concept of interaction between the molecular surfaces of the components of a binary mixture [Polymer 12 (1971) 389] has been extended to evaluate excess isentropic compressibility of the studied binary and ternary mixtures. It has been observed that κ_s^E values predicted by a graph-theoretical approach using connectivities of third degree for binary mixtures compare reasonably well with their corresponding experimental values and κ_s^E for ternary mixtures are of the same sign and order of magnitude.     

Refractive Properties of Binary Mixtures Containing 2-Methoxyethanol and n-Butylamine,Isobutylamine, sec-Butylamine and tert-Butylamine

Refractive index (n) and related properties such as molar refraction (R) have been investigated for 2-methoxyethanol (ME) + n-butylamine (n-BA) and 2-methoxyethanol (ME) + isobutylamine (iso-BA), 2-methoxyethanol (ME) + sec-butylamine (sec-BA) and 2-methoxyethanol (ME) + tert-butylamine (tert-BA) binary mixtures over the entire composition range, at different temperatures in the range 291.15 ≤? T/K ≤? 313.15. Furthermore, the excess molar refraction (R^E ) and deviation from ideality refractive index (Δn) have been examined, in order to identify the presence of intermolecular complexes in these binary liquid mixtures. The results obtained have been interpreted on the basis of specific intermolecular interactions between species.     

Study of molecular interaction in binary liquid mixtures of ethyl acetoacetate with chloroform and dimethylsulphoxide using excess acoustic parameters and spectroscopic methods

Densities and ultrasonic velocities were measured for binary liquid mixtures of ethyl acetoacetate (EAA) with chloroform (CHCl₃) and dimethylsulphoxide (DMSO) over the entire composition range. These experimental values were used to calculate the adiabatic compressibility (βs), intermolecular free length (L_f), excess molar volume (V^E), excess adiabatic compressibility (β_s^E) and excess intermolecular free length (L_f^E) for the liquid mixtures under consideration. In all the excess parameters, a positive deviation was observed in CHCl₃–EAA binary mixture, whereas a slight negative deviation was found for EAA–DMSO binary liquid mixture. These deviations were explained in terms of molecular interactions between like and unlike molecules and further affirmed by UV–Vis spectroscopic measurements in terms of polar and non-polar environment in the close proximity of solvatochromic dye. Fourier transform infrared spectroscopy (FT-IR) and proton-nuclear magnetic resonance (H¹ NMR) measurements have also been done to explain the molecular interaction in the binary liquid mixtures.     

Studies on solution properties of ternary mixture of acetophenone + n-amyl alcohol + dichloromethane and its corresponding binaries at 298.15 K

The excess values of molar volume (V ^E), viscosity deviation (Δη), deviation in isentropic compressibility (ΔK_S ), excess molar refraction (ΔR) and excess Gibbs energy of activation (ΔG^*E ) of viscous flow have been investigated from the experimentally measured densities, viscosities, sound speeds and refractive indices for three binary mixtures of acetophenone?+?n-amyl alcohol, acetophenone?+?dichloromethane and n-amyl alcohol?+?dichloromethane and their corresponding ternary mixtures at 298.15?K over the entire composition range. The calculated quantities are further fitted to the Redlich–Kister equation to estimate the binary fitting parameters and standard deviations from the regression lines. The excess or deviation properties were found to be either negative or positive depending on the molecular interactions and the nature of liquid mixtures and have been discussed in terms of molecular interactions and structural changes.     

Measurements of the Molar Heat Capacities and Excess Molar Heat Capacities for Acetonitrile + Diethylamine or sec-Butylamine Mixtures at Various Temperatures and Atmospheric Pressure

As a continuation of our studies of the excess functions of binary systems containing acetonitrile (1−x)–amines (x) mixtures, the molar heat capacity, Cp, and excess molar heat capacity, Cp ^E, of acetonitrile + diethylamine or sec-butylamine mixtures have been determined as a function of composition at 288.15, 293.15, 298.15 and 303.15 K at atmospheric pressure using a modified 1455 PARR solution calorimeter. The excess heat capacity data are positive for both systems over the whole composition range. The experimental data on the excess molar heat capacity are discussed in terms of the influence of the magnitude of the experimental excess molar enthalpy, H ^E, over the curve shaped for the experimental Cp ^E data, molecular interactions in the mixtures, isomeric effect of the amines and modeling of Cp ^E data.     

Thermophysical and thermoacoustical properties of benzaldehyde mixtures with ethylbenzene at 303.15, 308.15, and 313.15 K and a pressure of 0.1 MPa

Ultrasound velocity (u), density (ρ) and viscosity (η) measurements of benzaldehyde + ethylbenzene mixtures have been carried out at 303.15, 308.15, and 313.15 K. These values have been used to calculate the excess molar volume (V ^E), deviation in viscosity (δη), and deviation in isentropic compressibility (δβ_s), deviations in ultrasound velocity (δu), excess free volume (δV _f), excess intermolecular free length (δL _f) and excess Gibbs free energy of activation of viscous flow (δG ^E). McAllister’s three body interaction model is used for correlating kinematic viscosity of binary mixtures. The excess values were correlated using the Redlich-Kister polynomial equation to obtain their coefficients and standard deviations. The thermophysical properties under the study were fit to the Jouyban-Acree model. The observed variation of these parameters helps in understanding the nature of interactions in these mixtures. Further, theoretical values of the ultrasound speed were evaluated using theories and empirical relations.     

Thermodynamic Properties of Binary Mixtures of Cyclohexanone with n-Alkanols (C1–C5) at 293.15 K

The excess molar volumes (V^E), excess surface tensions (σ^E), and deviations in molar refraction (R^E) and isentropic compressibility (k_s^E) of binary mixtures of cyclohexanone with methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol have been determined over the entire composition range at 293.15 K. The results were fitted by the Redlich–Kister polynomial equation and the corresponding binary coefficients A_k have been derived. The standard deviations between the calculated and the experimental excess properties have been determined. The results provide information on the interactions of the molecules in the pure liquids as well as in the binary mixtures.     

Topological and thermodynamic investigations of molecular interactions of aniline and o-toluidine with chloroform

Molar excess volumes, V^E, molar excess enthalpies, H^E, and speeds of sound data, u, of chloroform (i) + aniline or o-toluidine (j) binary mixtures have been measured as a function of composition at 308.15 K. Isentropic compressibility changes of mixing, have been determined by employing speed of sound data. Topological investigations of V^E data reveals that aniline, chloroform and o-toluidine are associated entities and these (i + j) mixtures contain a 1:1 molecular complex. The IR studies lend further support to the nature and extent of interaction for the proposed molecular entity in the mixtures. H^E and values have also been calculated by employing Moelwyn-Huggins concept [Polymer 12 (1971) 387] taking topology of the constituents of the mixtures. It has been observed that calculated H^E and values compare well with their corresponding experimental values. The observed V^E, H^E and data have also been analyzed in terms of Flory theory.     

Volumetric properties of the water-ethylene glycol mixtures in the temperature range 278–333.15 K at atmospheric pressure

Density of the water-ethylene glycol binary mixtures was measured in the entire range of compositions in the temperature range 278–333.15 K (6 values) at atmospheric pressure using a vibration densimeter. Mixtures with low concentrations of ethylene glycol were studied at 15 temperatures in the range of 274–333.15 K. Excess molar volumes V _m ^E , the partial molar volumes of water -V ₁ and ethylene glycol, -V ₂, the coefficients of thermal volume expansion α of the mixture, the partial molar volume coefficients of thermal expansion of water $ \bar V_1 $ \bar V_1 and ethylene $ \bar V_2 $ \bar V_2 were calculated. Excess molar volumes were described using the Redlich-Kister equation. The density ρ of the mixture was found to increase with the increasing ethylene glycol concentration at all temperatures, but at low content of ethylene glycol the dependence ρ = f(T) of the mixture at ∼276.5 K passed through a maximum. The coefficient α increases sharply in the composition range 0 < x < 0.2, in the range 0.5 < x <1 remains almost unchanged, and at T > 277 K is positive for all compositions. The dependences $ \bar \alpha _1 $ \bar \alpha _1 = f (x) and $ \bar \alpha _2 $ \bar \alpha _2 = f (x) are complex in whole temperature range and are characterized by the presence of an extremum. V _m ^E values are negative at all temperatures, and upon increase in the temperature the deviation from ideality decreases (x is the mole fraction of ethylene glycol).     

Excess enthalpies and molecular interactions in solutions of 1-fluoroalkanes in alkanes,benzene or tetrachloromethane. A group contribution (DISQUAC) study

Molar excess enthalpies H ^E at 298.15 K and atmospheric pressure were determined for 12 binary liquid mixtures, 1-fluoropentane, 1-fluorohexane, or 1-fluorononane + a non-polar solvent (hexane, cyclohexane, benzene, or tetrachloromethane) and were interpreted by the DISQUAC group contribution model. 1-Fluoroalkane + n-alkane mixtures are characterized by two types of groups or contact surfaces, fluorine (F) and alkane (CH₃, CH₂), the remaining mixtures by the additional contact surfaces of the solvents (C₆H₁₂ C₆H₆, or CCl₄). The interchange energies, entirely dispersive, of the alkane-solvent contacts were determined independently from the study of solvent-alkane mixtures. The dispersive F-alkane parameters were assumed to equal the parameters of perfluoroalkanes + n-alkanes. The shape of the H ^E curves of 1-fluorolkane + polarizable solvent (C₆H₆, CCl₄) mixtures are best reproduced by the model when the quasi-chemical F-solvent parameters are assumed to equal zero. The quasi-chemical F-alkane (the same for n-alkanes and cyclohexane) and the dispersive F-solvent parameters were estimated in this work. The 1-fluoroalkane solutions in C₆H₆ or CCl₄ exhibit the characteristic features of polar solute + polarizable solvent mixtures, viz., the deviations from the ideality are less positive than in alkanes and the experimental H ^E curves are strongly asymmetrical.     

Acetonitrile - 2-Methyl-Propan-1-ol and Acetonitrile - 2-Methyl-Propan-2-ol Binary Mixtures and their Physicochemical Properties

The 1 H-NMR spectra of liquid binary mixtures of acetonitrile with 2-methyl-propan-1-ol (i-BtOH) and 2-methyl-propan-2-ol (t-BtOH), were recorded at 298 K over almost the whole range of mixed solvent compositions. From these data the values of spectral parameters, j i (ACN-i-BtOH) and j i (ACN-t-BtOH) were found. The relative permittivities ( k 12 ) and the densities ( d 12 ) of the mixed solvents were measured at 288.15 K, 293.15 K, 298.15 K, 303.15 K and 308.15 K. The experimental data were used to test some empirical equations of the type: y 12 = y 12 ( t ) and y 12 = y 12 ( X 1 ) [where: y 12 = d 12 or k 12 ]. From all these data, the deviations from ideality molar volumes , temperature coefficients of relative permittivities ( f 12 ) and the excess extrathermodynamic parameters were calculated. The values of these structural parameters are discussed in terms of interactions of acetonitrile with both alcohols.     

Ultrasonic velocity and apparent isentropic compressibilities in mixtures of nonelectrolytes

Ultrasonic velocities have been determined for binary mixtures of pyridine + n-alkanol (C₁-C₁₀) over the whole composition range at 25‡C. The excess isentropic compressibilities K _S ^E and apparent molar isentropic compressibilities K_Φ,s are estimated from these measurements. The K _S ^E values are negative for all the systems over the complete mole fraction range except pyridine + decanol for which small positive values are obtained. The standard partial molar isentropic compressibilitiesK‡ of the alkanols are positive and increase linearly with the chain length of the alkanol molecules. It indicates that a methylene functional group makes a positive contribution to the expansion coefficient of a solute in these mixtures.