Anil Kumar Nain

Physico-chemical studies of non-aqueous binary liquid mixtures at various temperatures

Abstract Densities, ϱ, viscosities, η, and ultrasonic velocities, u, have been measured for pure N,N-dimethylformamide (DMF), ethanol and their binary mixtures at 298.15, 303.15, 308.15, 313.15 and 318.15 K over the whole mole fraction range. From these data adiabatic compressibilities, β, intermolecular free lengths, Lf, relative associations, RA, excess adiabatic compressibilities, βE, excess free lengths, LEf, excess molar volumes, VE, excess viscosities, ηE, and excess free energies of activation of viscous flow, G∗ E , have been calculated. All the excess functions studied were found to be negative over the entire range of mole fraction. These properties are used to explain the intermolecular interactions between the components. Furthermore, activation enthalpies, ΔH∗ and entropies, ΔS∗ of viscous flow have been evaluated and their variations with concentration discussed.

Studies on molecular interactions in binary liquid mixtures by viscosity and ultrasonic velocity measurements at 303.15 K

Abstract The densities, viscosities, and ultrasonic velocities of pure ethanol, 1-hexanol, 1-octanol, acetonitrile, N,N-dimethylformamide, and of the binary mixtures of ethanol with 1-hexanol and 1-octanol, and those of acetonitrile with N,N-dimethylformamide were determined at 303.15 K. The excess adiabatic compressibility, excess intermolecular free length, excess volume, excess viscosity, excess acoustic impedance, and the molecular association have been calculated from the experimental data. These parameters are used to discuss the nature and the extent of intermolecular interactions in the mixtures.

Volumetric, ultrasonic and viscometric studies of molecular interactions in binary mixtures of aromatic+aliphatic alcohols at different temperatures

The densities, ρ, ultrasonic speeds, u and viscosities, η of pure benzyl alcohol, 1-propanol, 2-propanol and those of their binary mixtures, with benzyl alcohol as a common component, have been measured at 298.15, 303.15, 308.15 and 313.15 K over the entire composition range. The excess molar volume, V E, deviation in isentropic compressibility, Δk s , excess thermal expansivity, αE, deviations in ultrasonic speed, Δu and viscosity, Δη, partial molar volume and compressibility, and of 1-propanol/2-propanol in benzyl alcohol at infinite dilution have been evaluated from the experimental data. The results have been used to discuss the nature and strength of intermolecular interactions in these mixtures. The V E values have also been calculated theoretically by using the Florys statistical theory and Prigogine–Flory–Patterson theory. The calculated V E values were found in good agreement with the experimental V E values. The thermal expansivity, α and isothermal compressibility, k T have been calculated theoretically by using Florys theory and various hard sphere models, and were compared with experimental α and k T values.

Study of molecular interaction in ternary mixtures through ultrasonic speed measurements

Density (ρ) and ultrasonic speed (u) of ternary liquid mixtures: acetonitrile (ACN) + 1-propanol + benzene, + toluene, + chlorobenzene and + nitrobenzene, and those of pure components, have been measured as function of composition at 303.15 K. Using experimental data, the values of isentropic compressibility (K s ), intermolecular free length (L f ), molar ultrasonic speed (R m ), acoustic impedance (Z), excess isentropic compressibility ( ), excess free length ( ), excess volume (V E ) and excess acoustic impedance (Z E ) were computed. The increase or decrease of K s , L f , R m and Z with composition indicates the presence of interaction between the component molecules in the mixtures. The excess functions and V E are predominantly negative, while Z E is almost positive. This further supports the presence of significant interactions between the component molecules in these mixtures. Theoretical values of ultrasonic speed have been calculated for all the four ternary mixtures at different compositions using free length theory (FLT), collision factor theory (CFT), Nomotos (NOM) empirical relation and Van Dael and Vangeel (VDV) ideal mixing relation. A comparison of theoretical values of ultrasonic speed with those obtained experimentally reveals that, in general, CFT predicts the data reasonably well.

Study of Intermolecular Interaction in Dimethylsulphoxide + 1-Alkanols (1-Butanol, 1-Hexanol, 1-Octanol) At 303.15 K

Abstract The ultrasonic velocity, u, viscosity, η, and density, ρ of dimethylsulphoxide (DMSO), 1-butanol, 1-hexanol, 1-octanol, and of their binary mixtures, where DMSO is common component, have been measured at 303.15 K. From the experimental data, excess isentropic compressibility, K E s, excess intermolecular free length, LE f, excess velocity, u E, excess acoustic impedance, Z E, excess viscosity, ηE, excess free energy of activation of viscous flow, G*E, and excess rheochore, [R E] have been calculated. The behaviours of excess functions with composition of the mixtures suggest that the structure-breaking effect dominates over the interaction effect between the component molecules. Furthermore, the experimental values of u and η were fitted by empirical equations stating their dependence on composition of the mixtures. The experimental values of u have been compared with those calculated by using Nomoto and Van Dael relations.

Ultrasonic and viscometric studies of molecular interactions in binary mixtures of tetrahydrofuran with some aromatic hydrocarbons at temperatures from 288.15 to 318.15 K

Ultrasonic speed, u, and viscosity, η, of pure tetrahydrofuran (THF), benzene, toluene, o-xylene, m-xylene, p-xylene, mesitylene and those of their binary mixtures with THF as a common component, over the entire composition range expressed by mole fraction, x 1 of THF (0 ≤ x 1 ≤ 1), were measured at temperatures 288.15, 298.15, 308.15 and 318.15 K. From the experimental data, the deviations in isentropic compressibility, Δk s, in ultrasonic speed, Δu, and in viscosity, Δη were calculated. The partial molar compressibilities, and of THF and aromatic hydrocarbons in the mixtures over the whole composition range and and at infinite dilution and excess partial molar compressibilities, and , over the whole composition range and and at infinite dilution were calculated by using two different approaches. The variation of these parameters with composition and temperature of the mixtures are discussed in terms of molecular interaction in these mixtures. It is observed that the THF-aromatic hydrocarbon interaction in these mixtures follows the order: benzene > toluene > p-xylene > m-xylene > o-xylene > mesitylene. The effect of the number and position of the methyl groups in these aromatic hydrocarbons on the molecular interactions in these mixtures is also discussed.

Density and viscosity of magnesium sulphate in formamide + ethylene glycol mixed solvents

Densities (ρ) and viscosities (η) of different strengths of magnesium sulphate (MgSO4) in varying proportions of formamide (FA) + ethylene glycol as mixed solvents were measured at room temperature. The experimental values of ρ and η were used to calculate the values of the apparent molar volume, (φ1,), partial molar volume, (φ1,ℴ) at infinite dilution,A- andB-coefficients of the Jones-Dole equation and free energies of activation of viscous flow, (Δμ10*) and (Δμ20*), per mole of solvent and solute respectively. The behaviour of these parameters suggests strong ion-solvent interactions in these systems and also that MgSO4 acts as structure-maker in FA + ethylene glycol mixed solvents.

Ultrasonic, volumetric and viscometric studies of molecular interactions in binary mixtures of dimethylsulphoxide with polar substituted cyclohexanes at 30°C

The densities, ρ, ultrasonic speeds, u and viscosities, η of binary mixtures of dimethylsulphoxide (DMSO) with cyclohexanol, cyclohexanone and cyclohexylamine, with DMSO as a common component, over the whole composition range expressed by mole fraction of DMSO, including those of pure liquids have been measured at 30°C. By using the experimental values of ρ, u and η, the deviations in isentropic compressibility, Δk s, excess intermolecular free length, , excess molar volume, V E, deviations in viscosity, Δη, excess free energy of activation of viscous flow, G*E, partial molar compressibility and volume, and respectively of cyclohexanol/cyclohexanone/cyclohexylamine in DMSO at infinite dilution have been calculated. The variations of these parameters with composition of the mixture suggest that the strength of interactions in these mixtures follow the order: cyclohexanol < cyclohexanone < cyclohexylamine. The isothermal compressibility, kT for these binary mixtures has been theoretically calculated by using the Florys statistical theory and five hard sphere models and the results were compared with the experimental kT values. Further, the viscosities of these binary mixtures were theoretically predicted on the basis of various relations by using the experimental values of pure components and the results were compared with the experimental findings.

Volumetric, viscometric and refractive index study of amino acids in mixed solvents at 308.15 K

Densities, ρ, viscosities, η and refractive indices n D for solutions of (0.10, 0.20, 0.30, 0.40 and 0.50 M) glycine (Gly), DL-alanine (Ala) and L-serine (Ser) in aqueous 1-propanol (10 and 30% v/v) at 308.15 K have been determined. These data have been used to calculate apparent molar volumes, φv, partial molar volumes, and Falkenhagen and Jones–Dole coefficients, A and B, respectively. Free energies of activation of viscous flow, and per mole of solvent and solute, respectively, were obtained by using transition state theory to the B-coefficient data. The molar refractive indices, R D were calculated from the experimental values of refractive indices for all the three amino acids + aqueous 1-propanol ternary mixtures. These parameters were used to discuss the solute–solute and solute–solvent interactions and also the effect of cosolvent (1-propanol) on these interactions.

Interactions in Binary N,N-Dimethylacetamide + Ethanol and Ternary Lithium Nitrate + N,N-Dimethylacetamide + Ethanol Mixtures

Abstract Excess volume (VE ), excess viscosity (η E ), excess free energy of activation of viscous flow (G∗E ), and Grunberg-Nissan interaction parameter (d) of binary mixtures N,N-dimethylacetamide (DMA) + ethanol have been calculated from the viscosities (η) measured at 298.15, 303.15, 308.15, 313.15 and 318.15 K over the whole composition range. All the excess functions studied are found to be negative over the entire range of composition indicating strong interaction between DMA and ethanol molecules. Densities (ρ) and ultrasonic velocities (u) of lithium nitrate in DMA + ethanol mixtures have been measured at above mentioned temperatures as function of DMA mol fraction. From these experimental data, isentropic compressibility (ks ), intermolecular free length (Lf ), and relative association (RA ) of LiNO3 + DMA + ethanol ternary mixtures have been computed. These properties are used to discuss ion-solvent interaction and selective solvation of ions by the component molecules of the liquid mixture.