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Abburi Krishnaiah - One of the best experts on this subject based on the ideXlab platform.

  • Vapor−Liquid Equilibria and Excess Enthalpies for Binary Systems of Dimethoxymethane with Hydrocarbons
    Journal of Chemical & Engineering Data, 2006
    Co-Authors: K.v.n. Suresh Reddy, Y. V. L. Ravi Kumar, D. H. L. Prasad, Abburi Krishnaiah
    Abstract:

    Isobaric vapor−liquid equilibrium data at 95.96 kPa for the three binary systems of dimethoxymethane with hexane, cyclohexane, and benzene are determined. A Swietoslawski-type ebulliometer is used for the measurements. The experimental T−x data are used to estimate Wilson parameters, and these parameters in turn are used to calculate vapor-phase compositions and activity coefficients. The activity coefficients are useful to calculate excess Gibbs Function (G E/RT). All the systems studied here do not exhibit azeotropes. Excess Gibbs Function values are positive over the entire range of composition for all the systems. Excess enthalpies are reported for the binary systems of dimethoxymethane with hexane, cyclohexane, and benzene at 298.15 K. The H E data are interpreted on the basis of intermolecular interactions between unlike molecules.

  • Vapor-Liquid Equilibria for the Binary Systems of Dimethoxymethane with Some Fuel Oxygenates
    Journal of Chemical & Engineering Data, 2004
    Co-Authors: Suresh K. V. N. Reddy, H. L. Dasika Prasad, Abburi Krishnaiah
    Abstract:

    Isobaric vapor−liquid equilibrium data at 95.96 kPa for the three binary systems of dimethoxymethane with methyl tert-butyl ether, diisopropyl ether, and 2-propanol are determined. A Swietoslawski-type ebulliometer is used for the measurements. The experimental T−x data are used to estimate Wilson parameters, and the parameters is in turn are used to calculate vapor compositions and activity coefficients. The activity coefficients are useful for calculating the excess Gibbs Function (GE/RT). None of the systems studied here exhibit azeotropes. Excess Gibbs Function values are positive over the entire range of composition for all of the systems.

Rainer Feistel - One of the best experts on this subject based on the ideXlab platform.

  • A Gibbs Function for seawater thermodynamics for −6 to 80 °C and salinity up to 120 g kg–1
    Deep Sea Research Part I: Oceanographic Research Papers, 2008
    Co-Authors: Rainer Feistel
    Abstract:

    The specific Gibbs energy of seawater is determined from experimental data of heat capacities, freezing points, vapour pressures and mixing heats at atmospheric pressure in the range � 6t o 801C in temperature and 0–120 g kg –1 in absolute salinity. Combined with the pure-water properties available from the 1996 Release of the International Association for the Properties of Water and Steam (IAPWS-95), and the densities from the 2003 Gibbs Function of seawater, a new saline part of the Gibbs Function is developed for seawater that has an extended range of validity including elevated temperatures and salinities. In conjunction with the IAPWS 2006 Release on ice, the correct description of concentrated brines by the new formulations permits an accurate evaluation of sea ice properties down to salinity saturation temperatures. The new Gibbs Function is expressed in terms of the temperature scale ITS-90. Its input variable for the concentration is absolute salinity, available from the new Reference-Composition Salinity Scale of 2008.

  • A Gibbs–Pitzer Function for high-salinity seawater thermodynamics
    Progress in Oceanography, 2007
    Co-Authors: Rainer Feistel, Giles M. Marion
    Abstract:

    Abstract A high-salinity Gibbs Function for seawater is derived from Pitzer equations of the sea salt components, in conjunction with the 2003 Gibbs Function of seawater for low salinities. Various properties, computed from both formulations by thermodynamic rules, are compared with each other, and with high-salinity measurements. The new Gibbs–Pitzer Function presented in this paper is valid in the range 0–110 g kg−1 in absolute salinity, −7 to +25 °C in temperature, and 0–100 MPa in applied pressure. The formulation is expressed in the International Temperature Scale 1990 (ITS-90), and is consistent with the International Standard for Fluid Water (IAPWS-95), and with the 2005/2006 equations of state of ice Ih.

Carlos Lafuente - One of the best experts on this subject based on the ideXlab platform.

  • Vapor-liquid equilibrium and excess properties of the binary mixtures formed by ethyl isobutyrate and n-alkanols
    The Journal of Chemical Thermodynamics, 2019
    Co-Authors: Najla Ben Mahdoui, Raouia Abidi, Héctor Artigas, Monia Hichri, Carlos Lafuente
    Abstract:

    Abstract This contribution reports densities together with the corresponding excess molar volumes, and excess molar enthalpies of the binary mixtures formed by ethyl isobutyrate and n-alkanols (from methanol to 1-butanol) at two temperatures (303.15 and 323.15) K and at atmospheric pressure (p = 0.1 MPa). These excess properties were correlated with composition using the Redlich-Kister equation. Excess molar volumes and enthalpies are positive, except the excess molar volumes for the mixture ethyl isobutyrate and methanol. Furthermore, the vapor-liquid equilibrium data for these mixtures at different experimental conditions have been also presented. Both the isothermal VLE at two temperatures (303.15 and 323.15) K and isobaric VLE at two pressures (40.000 and 101.325) kPa were measured. Some of the systems exhibit azeotropic points. The VLE data were found thermodynamically consistent. From experimental data the activity coefficients along with excess Gibbs Function (isothermal) and reduced excess Gibbs Functions (isobaric) were obtained and correlated with composition using the Wilson equation. These excess Gibbs Function and reduced excess Gibbs Functions were found positive. Finally, we have used our experimental VLE data to check the reliability of modified UNIFAC predictions.

  • (Vapour + liquid) equilibrium and excess Gibbs Functions of ternary mixtures containing 1-butanol or 2-butanol, n-hexane, and 1-chlorobutane at T = 298.15 K
    The Journal of Chemical Thermodynamics, 2009
    Co-Authors: S. Martínez, Carlos Lafuente, Isabel Bandrés, Luz M. Ballesteros, Ignacio Gascón
    Abstract:

    Abstract Isothermal (vapour + liquid) equilibrium data for the ternary mixtures 1-butanol + n-hexane + 1-chlorobutane and 2-butanol + n-hexane + 1-chlorobutane have been studied with a recirculating still at T  = 298.15 K. The experimental data were satisfactorily checked for thermodynamic consistency using the method of van Ness. Activity coefficients and excess Gibbs Function have been correlated with the Wilson equation. The G E values obtained for the two ternary systems are very similar.

Danxing Zheng - One of the best experts on this subject based on the ideXlab platform.

  • New Approach for Absorbent Species Selection with Excess Gibbs Function
    Industrial & Engineering Chemistry Research, 2013
    Co-Authors: Danxing Zheng, Li Dong
    Abstract:

    Absorption capacities were analyzed based on 33 sets of vapor–liquid equilibrium literature data that focused on eight solute-based binary systems, namely, carbon dioxide, dimethyl ether, ethylene, difluoromethane, water, methane, 1,1,1,2-tetrafluoroethane, and sulfur dioxide. The absorbents were classified into solvent type and ionic liquid type. The regularities of the excess Gibbs Function (GE) of the binary systems were investigated by evaluating the macroscopic properties and the influence of intermolecular interactions between the solute and the absorbent based on the concept of local composition model. The extreme value (GEmax) and the absorption potential (ψi) were proposed as absorbent selection criteria. An evaluation method predicting the activity coefficient and evaluating the systems with GEmax and ψi through the UNIFAC model was established. Consequently, the validity study of the new approach for the eight solute-based binary systems was in agreement with previously assessed experimental be...

  • Maximum excess Gibbs Function of working pairs and absorption cycle performance
    International Journal of Refrigeration, 2001
    Co-Authors: Danxing Zheng
    Abstract:

    Abstract This work focuses attention on the contribution of the excess Gibbs Function of the working pair to the performance of the absorption cycle. Using water/triethylene glycol, water/glycerol, water/diethylene glycol, water/glycol and water/sulfolane as working pairs, respectively, the exergy analysis and simulation for the absorption heat transformer show that the maximum excess Gibbs Function of the working pair is an essential description of the cycle performance to assess new working pairs. However, this work modified Morrissey and Odonnell's assertion (Morrissey AJ, Odonnell JP. Endothermic solutions and their application absorption heat pumps. Chem Eng Res Des. 1986; 64: 404–6) and proposed that the systems exhibiting the negative deviation from the Raoult's law may be valid within an appropriate range, one or several systems may exist, and their performances overpass others.

Suresh K. V. N. Reddy - One of the best experts on this subject based on the ideXlab platform.

  • Vapor-Liquid Equilibria for the Binary Systems of Dimethoxymethane with Some Fuel Oxygenates
    Journal of Chemical & Engineering Data, 2004
    Co-Authors: Suresh K. V. N. Reddy, H. L. Dasika Prasad, Abburi Krishnaiah
    Abstract:

    Isobaric vapor−liquid equilibrium data at 95.96 kPa for the three binary systems of dimethoxymethane with methyl tert-butyl ether, diisopropyl ether, and 2-propanol are determined. A Swietoslawski-type ebulliometer is used for the measurements. The experimental T−x data are used to estimate Wilson parameters, and the parameters is in turn are used to calculate vapor compositions and activity coefficients. The activity coefficients are useful for calculating the excess Gibbs Function (GE/RT). None of the systems studied here exhibit azeotropes. Excess Gibbs Function values are positive over the entire range of composition for all of the systems.