Perfluorinated n-Alkanes C_mF_2m+2 (m < 7):  Second pVT-Virial Coefficients, Viscosities, and Diffusion Coefficients Calculated by Means of an (n-6) Lennard-Jones Temperature-Dependent Potential

Abstract

The perfluorinated n-alkanes C m F2 m +2 (m = 1 to 6) are widely used and expensive substances that are not only of technological interest for the semiconductor industry but also powerful greenhouse gases having an important impact on the atmosphere. This paper presents tables with recommended thermophysical data in the temperature range (200 to 1000) K at pressures of ≤0.1 MPa. Second pVT-virial coefficients B, viscosities η, and diffusion coefficients D are calculated by means of an (n-6) Lennard-Jones temperature-dependent potential. The potential parameters, equilibrium distance, and potential well depth are defined as functions of the temperature T by solving an ill-posed problem of minimization of the squared deviations between measured and calculated B, η, and D, normalized to their experimental error. Tables with potential parameters as well as algorithms for calculation of the potential-dependent properties are given. New tables of the harmonic vibrational frequencies of n-C4F10, n-C5F12, and n-C6F14, which are required as input parameters in the course of the calculations, are also presented.

Effective (n-6) Lennard-Jones Potentials with Temperature-Dependent Parameters Introduced for Accurate Calculation of Equilibrium and Transport Properties of Ethene, Propene, Butene, and Cyclopropane

“…As was observed earlier for the alkanes C m H 2 m +2 , and perfluoroalkanes C m F 2 m +2 R m ( T = 0 K) and ε( T = 0 K) of the alkenes and cyclopropane increase with increasing size of the molecules. Also comparable to our findings for C m H 2 m +2 and C m F 2 m +2 , the repulsive parameter n does not follow a simple trend and varies between 17.1 (propene) and 38.3 (iso-butene).…”

“…The LJTDP has been successfully applied before to a number of pure gases like the alkanes 31,32 and perfluoroalkanes. 33 We have shown that it performs also very well in the prediction of B, η, and D of binary mixtures of alkanes and other gases. 34,35 To give a comprehensive overview on the molecules with sum formula C m H 2m , we not only consider the alkenes but also try to include the two cyclic compounds cyclopropane (C 3 H 6 ) and cyclobutane (C 4 H 8 ) in our studies.…”

“…In this work, we apply our model of the ( n -6) Lennard-Jones temperature-dependent potential, ( n -6) LJTDP, to calculate and predict the second pVT virial coefficient B , the viscosity η, and the diffusion coefficient D of the low density alkenes C m H 2 m , m < 5. The LJTDP has been successfully applied before to a number of pure gases like the alkanes , and perfluoroalkanes . We have shown that it performs also very well in the prediction of B , η, and D of binary mixtures of alkanes and other gases. , To give a comprehensive overview on the molecules with sum formula C m H 2 m , we not only consider the alkenes but also try to include the two cyclic compounds cyclopropane (C 3 H 6 ) and cyclobutane (C 4 H 8 ) in our studies.…”

Experimental Study of p–ρ–T Relationship of Compressed Liquid Phase for Octafluoropropane and Two near Azeotropic Ternary HFC/HC Mixtures

“…It is accepted that octafluoropropane is completely stable and entirely nontoxic. 6 Only a few liquid phase density measurements for PFC-218 are reported in the open literature. Table 1 gives an overview of the literature sources for experimental p−ρ−T data for octafluoropropane together with the corresponding temperature and pressure region, and the number of data points.…”

“…Among them, octafluoropropane (C 3 F 8 , PFC-218 in ANSI/ASHRAE nomenclature) is widely used in the most varied industrial applications, in particular under the name R-218 as a component of mixture refrigerants. It is accepted that octafluoropropane is completely stable and entirely nontoxic …”