Linear Isotherms for Dense Fluids: Extension to Mixtures

Parsafar, Gholamabbas; Mason, Edward A.

doi:10.1021/j100058a040

Cited by 37 publications

(23 citation statements)

References 7 publications

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“…[1][2][3] • The Tait-Murnaghan relation, which states that the bulk modulus κ T -1 of a liquid is a linear function of pressure. [3][4][5] Another less well-known empirical regularity of fluids is the Zeno line. 1,2 Along the contour defined by Z ) 1, where the compressibility factor is the same as for an ideal gas, the density of many fluids has been found to be nearly a linear function of temperature.…”

Section: Introductionmentioning

confidence: 99%

The Zeno (Z = 1) Behavior of Equations of State: An Interpretation across Scales from Macroscopic to Molecular

et al. 2000

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The regularity exhibited by fluids along the contour of the unit compressibility factor in the temperaturedensity plane, where Z t PV/RT ) 1, is explored as a means for testing and improving the volumetric equations of state. For a wide range of pure fluids, this contour, known as the Zeno line, has been empirically observed to be nearly linear from the Boyle temperature of the low-density vapor to around the triple point in the liquid region. The Z ) 1 contour thus offers a quantitative criterion for interpreting intermolecular interactions. For H 2 O, CH 4 , and CO 2 , experimental results are compared with predictions from macroscopic PVT equations of state and with predictions from NVT molecular simulations. Reasonably straight Zeno lines result from commonly used macroscopic EOS models, such as the Redlich-Kwong-Soave (RKS) and the Peng-Robinson (PR). Although quantitative agreement between predicted and experimental Zeno behavior was not exact, the general trends suggest that these macroscopic models adequately capture the dynamic balance that exists between repulsive and attractive forces along the Zeno contour. From molecular dynamics simulations, the Lennard-Jones, the Simple Point Charge (SPC), and the extended SPC/E models of pure H 2 O also yielded Zeno lines close to experimentally measured values over a wide range of densities. Density-scaled radial distribution functions indicate that the degree of long-range ordering was nearly invariant along the Zeno line, but hydration numbers and cluster sizes varied markedly.

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Section: Introductionmentioning

confidence: 99%

The Zeno (Z = 1) Behavior of Equations of State: An Interpretation across Scales from Macroscopic to Molecular

et al. 2000

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“…This paper describes the behavior of the thermal pressure coefficients, measured between pressures of 0.1 and 150 MPa and temperatures of 313.15 and 383.15 K, for liquid n-Pentadecane (C15), n-Heptadecane (C17), n-octadecane (C18) and n-nonadecane (C19). When measurements of this property are carried out over a sufficiently wide range of pressures (as is the case in this work), the thermal pressure coefficients data can be integrated so as to generate other thermophysical properties (including density), provided that an appropriate set of initial conditions is available [19][20][21][22][23]. These include knowledge of the density and the thermal pressure coefficients data at a reference pressure (the most convenient being atmospheric pressure).…”

Section: Experimental Tests and Discussionmentioning

confidence: 99%

Calculation of Thermal Pressure Coefficient of Dense C15H32, C17H36, C18H38 and C19H40 Using pVT Data

Moeini¹,

Mahdianfar²

2012

JMP

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The thermal pressure coefficients in liquid n-Pentadecane (C15), n-Heptadecane (C17), n-octadecane (C18) and n-nonadecane (C19) was measured using pVT data. The measurements were carried out at pressures up to 150 MPa in the temperature range from 293 to 383 K. The experimental results have been used to evaluate various thermophysical properties such as thermal pressure coefficients up to 150 MPa with the use of density and temperature data at various pressures. New parameters of the linear isotherm regularity, the so-called LIR equation of state, are used to calculate of thermal pressure coefficients of n-Pentadecane (C15), n-Heptadecane (C17), n-octadecane (C18) and n-nonadecane (C19) dense fluids. In this paper, temperature dependency of linear isotherm regularity parameters in the form of a first order has been developed to second and third order and their temperature derivatives of new parameters are used to calculate thermal pressure coefficients. The resulting model predicts accurately thermal pressure coefficients from the lower density limit at the Boyle density at the from triple temperature up to about double the Boyle temperature. The upper density limit appears to be reached at 1.4 times the Boyle density. These problems have led us to try to establish a function for the accurate calculation of the thermal pressure coefficients based on the linear isotherm regularity theory for different fluids.

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“…According to the one-fluid approximation, 8 the regularity holds for the dense fluid mixtures as well. 9,10 LIR is able to predict many experimentally known regularities for dense pure fluids and fluid mixtures. [11][12][13] On the basis of a simple model, the temperature dependencies of the LIR parameters are found to be 7 where A 1 and B 1 are related to the attraction and repulsion terms of the average effective pair potential and A 2 is related to the nonideal thermal pressure.…”

Section: Linear Isotherm Regularity In the Reduced Formmentioning

confidence: 99%

Prediction of the Temperature and Density Dependencies of the Parameters of the Average Effective Pair Potential Using Only the LIR Equation of State

1999

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In this work we have studied the density and temperature dependencies of the parameters of the average effective pair potential using linear isotherm regularity (LIR). Such a potential is considered to be the interaction of two nearest neighbor molecules in which all of their longer range interactions are added to it, and also the effect of the medium on the charge distributions of two neighboring molecules is included. We have found that the density dependencies of the parameters of the average effective pair potential are negligible for densities greater than the Boyle density for which the LIR is valid. The parameter σ, the separation at which the potential is zero, increases with temperature while the depth of the potential well, , decreases. Furthermore, analytical expressions for and σ are obtained in terms of the LIR parameters. Using these parameters for the average effective pair potential, a strong principle of corresponding states is proposed.

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Linear Isotherms for Dense Fluids: Extension to Mixtures

Cited by 37 publications

References 7 publications

The Zeno (Z = 1) Behavior of Equations of State: An Interpretation across Scales from Macroscopic to Molecular

The Zeno (Z = 1) Behavior of Equations of State: An Interpretation across Scales from Macroscopic to Molecular

Calculation of Thermal Pressure Coefficient of Dense C<sub>15</sub>H<sub>32</sub>, C<sub>17</sub>H<sub>36</sub>, C<sub>18</sub>H<sub>38</sub> and C<sub>19</sub>H<sub>40</sub> Using <i>pVT</i> Data

Prediction of the Temperature and Density Dependencies of the Parameters of the Average Effective Pair Potential Using Only the LIR Equation of State

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