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Fundamental Equation of State for Fluid Tetrahydrofuran



Felix Fiedler, Joel Karog, Eric W. Lemmon, Monika Thol


An empirical equation of state in terms of the Helmholtz energy for tetrahydro- furan is presented. In the validity range from the triple-point temperature up to 550 K and pressures up to 600 MPa, the equation of state enables the calculation of all thermodynamic properties in the liquid, vapor, and super-critical regions including saturation states. Based on an extensive literature review, experimental data are represented within their experimental uncertainty. In the homogeneous liquid phase at atmospheric pressure, the uncertainty in density is 0.015%, speed of sound is represented with an uncertainty of 0.03%, and isobaric heat capacity has an uncertainty of 0.4%. Isobaric heat capacities in the homogeneous vapor phase are described with an uncertainty of 0.2%. Higher uncertainties occur above atmospheric pressure for all homogeneous properties. Depending on the temper- ature range, vapor pressure can be calculated with an uncertainty of 0.02% up to 3%. The extrapolation behavior is evaluated comprehensively.
International Journal of Thermophysics


Helmholtz energy, tetrahydrofuran, THF, thermodynamic properties, equation of state


Fiedler, F. , Karog, J. , Lemmon, E. and Thol, M. (2023), Fundamental Equation of State for Fluid Tetrahydrofuran, International Journal of Thermophysics, [online],, (Accessed June 22, 2024)


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Created October 9, 2023