Equations of State for n-Hexadecane and n-Docosane

• Published in: International journal of thermophysics Vol. 43; no. 10
• Main Authors: Romeo, Raffaella, Lemmon, Eric W.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-10-2022; Springer Nature B.V
• Subjects: Classical Mechanics; Condensed Matter Physics; Density; Equations of state; Geophysics; Hexadecane; Independent variables; Industrial Chemistry/Chemical Engineering; Mathematical analysis; Physical Chemistry; Physics; Physics and Astronomy; Sound; Specific heat; Thermodynamic properties; Thermodynamics; Uncertainty; Vapor pressure; Helmholtz energy; Equations of state; Thermodynamic properties; hexadecane; docosane
• ISSN: 0195-928X; 1572-9567
• DOI: 10.1007/s10765-022-03059-0

Equations of state for
n
-hexadecane (C
16
H
34
) and
n
-docosane (C
22
H
46
) have been developed as functions of the Helmholtz energy with independent variables of temperature and density. The equations were developed based on experimental values of density, speed of sound, isobaric heat capacity, and vapor pressure. With these equations, all thermodynamic properties of
n
-hexadecane and
n
-docosane can be calculated. For
n
-hexadecane, the uncertainty in vapor pressure is 0.5 %. The uncertainty of the saturated liquid density is 0.05 % from the triple point up to 400 K, and 0.2 % at higher temperatures. The uncertainty in densities is within 0.5 %. The speed of sound and isobaric heat capacity can be calculated within 0.25 %. The uncertainties of the properties calculated with the equation for
n
-docosane are 5 % for vapor pressure, 0.1 % for saturated liquid density, 1 % for density, 0.5 % and 1 % for speed of sound at atmospheric pressure and higher pressures, respectively, and within 3 % for heat capacity.