Theory of hydrogen bonding in supercritical fluids

Gupta, Ram B.; Panayiotou, Costas; Sánchez, Isaac C.; Johnston, Keith P.

doi:10.1002/aic.690380811

Cited by 83 publications

(81 citation statements)

References 55 publications

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“…Such an approach is well developed theoretically for describing the hydrogen bonding in supercritical fluids (e.g. Luck 1980;Gupta et al 1992) and its potential applicability to any fluid has been demonstrated (Barelko et al 1994;Gerya and Perchuk 1997).…”

Section: Derivation Of Basic Equationsmentioning

confidence: 99%

Semi-empirical Gibbs free energy formulations for minerals and fluids for use in thermodynamic databases of petrological interest

et al. 2004

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The P-T partition function in statistical thermodynamics can be used to derive semi-empirical formulations of the Gibbs free energy G for minerals and fluids. Parameterization of these equations includes simultaneous regression of experimental heat capacity and molar volume data, allowing fitting, appraisal and optimization of various data sources, as required in the construction of internally consistent petrological data bases. This approach can also be extended to minerals with k-transitions and to fluids by considering the Gibbs free energy as a function of pressure P, temperature T and an ordering parameter X a , so that accurate modelled representation and extrapolation of the thermodynamic properties of large numbers of petrologically significant minerals and coexisting fluids can be attained. The ordering parameter is chosen to denote the equilibrium mole fraction (thermodynamic probability) of ordered clusters (structural units) in a substance when G(T,P, X a ) ¼ min. The procedure is tested on existing experimental data for the system MgO-SiO 2 -H 2 O. The proposed Gibbs free energy formulation permits thermodynamic properties of minerals, fluids and phase equilibria to be described and extrapolated over a wide range of pressure (0-800 kbar) and temperature (20-3000 K), thus allowing effective use in thermodynamic data bases of petrological interest.

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Section: Derivation Of Basic Equationsmentioning

confidence: 99%

Semi-empirical Gibbs free energy formulations for minerals and fluids for use in thermodynamic databases of petrological interest

et al. 2004

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“…Gupta. ing the equilibrium between formation and rupture of h-bonds using statistical thermodynamics, known as lattice fluid h-Ž . Ž bonding theory LFHB Veytsman, 1990;Panayiotou and Sanchez, 1991;Gupta et al, 1992;Gupta and Johnston, 1994; . Gupta and Prausnitz, 1996 .…”

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confidence: 99%

Lattice‐fluid equation of state with hydrogen‐bond cooperativity

2002

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Hydrogen bonding plays an important role in thermodynamic properties of polar fluids. Existing equations of state that include h-bonding cannot accurately predict the phase beha®ior for polar fluids. In the theories for h-bond-chain forming molecules, h-bonding strength is considered a constant at a gi®en temperature and pressure. Infrared spectroscopy and ab initio calculations show that the h-bonding strength depends on whether or not the molecule was pre®iously h-bonded at other sites. When an h-bond is formed between an already hydrogen-bonded species and a free species, the second h-bond has different energetic characteristics from the primary h-bond. In the case of l -alkanol self-h-bonding, the equilibrium constant for the second h-bond is ten times that for the primary h-bond. This phenomenon called h-bond cooperati®ity was incorporated in a lattice

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“…The hydrogen-bonding Helmholtz energy is found from a proposal of Veytsman (Veytsman, 1990;Panayiotou and Sanchez, 1991;Gupta et al, 1992) and further improvement by Gupta and Johnston (1994) using local-segment density. The derivation was based on the combinatorial expression for distributing hydrogen bonds between given donor and acceptor sites.…”

Section: Systems With Specific Interactions (Hydrogen Bonding)mentioning

confidence: 99%

Vapor−Liquid Equilibria for Solvent−Polymer Systems from a Perturbed Hard-Sphere-Chain Equation of State

Gupta

Prausnitz

1996

Ind. Eng. Chem. Res.

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Vapor−liquid equilibria (VLE) for solvent−polymer mixtures at modest pressures are obtained from a perturbed hard-sphere-chain equation of state. This equation of state is the sum of a hard-sphere-chain term as the reference system and a van der Waals attractive term as the perturbation. The reference equation follows from the Percus−Yevick integral theory coupled with chain connectivity as described by Chiew. The effect of specific interactions, such as hydrogen bonding, is introduced through the proposal of Veytsman based on the statistical distribution of hydrogen bonds between donor and acceptor sites suggested by molecular structure. Calculated and observed vapor−liquid equilibria are presented for nonpolar, polar, and hydrogen-bonding solvent + homopolymer systems. Pure-component parameters (number of segments per molecule, segment−segment energy, and segment diameter) are obtained from pure-component properties: liquid density and vapor pressure data for normal fluids and pressure−volume−temperature data for polymers. A binary energy interaction parameter must be obtained from limited VLE data for each binary system; this parameter appears to be independent of temperature and composition over a useful range. Theoretical correlations and predictions are in good agreement with experiment.

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Theory of hydrogen bonding in supercritical fluids

Cited by 83 publications

References 55 publications

Semi-empirical Gibbs free energy formulations for minerals and fluids for use in thermodynamic databases of petrological interest

Semi-empirical Gibbs free energy formulations for minerals and fluids for use in thermodynamic databases of petrological interest

Lattice‐fluid equation of state with hydrogen‐bond cooperativity

Vapor−Liquid Equilibria for Solvent−Polymer Systems from a Perturbed Hard-Sphere-Chain Equation of State

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