M. V. Prabhakara Rao

Excess enthalpies of binary mixtures of N,N-dimethylformamide with substituted benzenes at 298.15 K

Abstract The excess molar enthalpies H E of binary solvent mixtures of N,N-diemthylformamide with toluene, ethylbenzene, chlorobenzene, bromobenzene, nitrobenzene and aniline have been measured with a new paar 1451 solution calorimeter at 298.15 K over the entire range of composition. The experimental values of H E are positive in the mixtures of N,N-dimethylformamide with toluene and ethylbenzene over the entire range of composition. The values of H E are negative over the whole range of composition in the mixtures of N,N-dimethylformamide with chlorobenzene, bromobenzene, nitrobenzene and aniline. The results are discussed with regard to the associating abilities of the components.

Activity coefficients and excess Gibbs free energies for binary mixtures of N,N-dimethylformamide with substituted benzenes

Abstract Vapour-liquid equilibrium (VLE) and boiling point data have been measured for binary mixtures of N , N -dimethylformamide with substituted benzenes, of different compositions, in a Swietoslawski-type ebulliometer. The mixtures include N , N -dimethylformamide with ethylbenzene; as well as chlorobenzene, and bromobenzene, with aniline. The measurements were made at 712 mm Hg. The experimental temperature-mole fraction data were used to estimate Wilson parameters, These, in turn, were used to calculate vapour compositions, boiling points and activity coefficients, from which the excess Gibbs free energies G E were calculated. The observed and calculated values are interpreted in terms of specific interaction.

Ultrasonic studies of N,N-dimethylformamide +cyclohexanone + 1-alkanols at 303.15 K

Isentropic compressibilities (k s) and deviation in isentropic compressibilities ( ) have been determined from the measurements of ultrasonic sound velocity (u) and densities (ρ) for the ternary mixtures of N,N-dimethylformamide (DMF), and cyclohexanone with 1-propanol, 1-butanol, 1-pentanol and 1-hexanol at 303.15u2009K. The relative magnitude and sign of have been interpreted in terms of possible molecular interactions between the unlike molecules. The deviation in k′s values are negative throughout the range of volume fraction in all four ternary mixtures.

Excess volumes of binary mixtures of triethylamine with aromatic hydrocarbons at 308.15 K

Abstract Venkatesu, P. and Rao, M.V.P., 1994. Excess volumes of binary mixtures of triethylamine with aromatic hydrocarbons at 308.15 K. Fluid Phase Equilibria 93; 369-376. Excess volume data on mixing for binary mixtures of triethylamine with benzene toluene o -xylene, m -xylene, p -xylene and ethylbenzene have been measured as a function of composition at 308.15 K. The V E values are negative in mixtures of triethylamine with toluene o -xylene, m -xylene, p -xylene and ethylbenzene and an inversion of sign from positive to negative is observed in the mixture triethylamine with benzene. The experimental V E are analysed in the light of Flory theory.

Excess molar enthalpies of N, N-dimethylacetamide with substituted benzenes at 298.15 K

Abstract Excess molar enthalpies ( H E ) of binary mixtures of N , N -dimethylacetamide with ethylbenzene, chlorobenzene, bromobenzene, nitrobenzene, aniline and acetophenone have been measured with a Parr 1451 calorimeter at 298.15xa0K, over the entire range of composition. The experimental values of H E are positive in the mixture of N , N -dimethylacetamide with ethylbenzene. The other experimental values of H E are negative. The results are discussed with regard to the associating abilities of the components.

Solid-liquid equilibria of long chain n-alkanes (C18-C28) in N, N-dimethylacetamide

Abstract Solid–liquid equilibria (SLE) of the n -alkanes (octadecane, nonadecane, eicosane, heneicosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, heptacosane and octacosane) in N , N -dimethylacetamide (DMA) are reported. The data has been measured by the dynamic method from 275xa0K to the melting temperatures of the n -alkane. The experimental results have been correlated by the Redlich–Kister equation with two and three parameters and the NRTL equation.

Excess enthalpies of ethyl acetate and butyl acetate with 2-alkoxyethanols at 298.15 K

The excess molar enthalpies (HE) of binary solvent mixtures of ethyl acetate and butyl acetate with 2-alkoxyethanols at 298.15 K have been measured over the entire range of composition with paar 1451 solution calorimeter. The 2-alkoxyethanols are 2-methoxyethanol, 2-ethoxyethanol and 2-butoxyethanol. All the systems are characterised by endothermic mixing over the entire range of composition, for which HE is positive. The HE data are interpreted on the basis of possible intermolecular interactions between unlike molecules of the components.

Excess volumes and viscosities of binary mixtures of trichloroethylene with branched alcohols

Abstract Excess volumes (VE) and viscosities (η) of binary liquid mixtures of trichloroethylene with branched alcohols have been measured as a function of composition at 303.15 K. The branched alcohols include 2-propanol, 2-methyl-1-propanol, 3-methyl-1-butanol, 2-butanol and 2-methyl-2-propanol. Further, the deviation in viscosities (Δlnη) have been computed from viscosity data. The VE values are positive in mixtures of trichloroethylene with 2-propanol, 2-butanol, 2-methyl-2-propanol and an inversion of sign from negative to positive is observed in the mixtures of trichloroethylene with 2-methyl-1-propanol and 3-methyl-1-butanol. The values of Δlnη are negative in all the mixtures except at lower mole fraction of trichloroethylene in the system trichloroethylene with 3-methyl-1-butanol.