RT Journal Article
T1 Study of the solid–liquid–vapour phase equilibria of flexible chain molecules using Wertheim’s thermodynamic perturbation theory
A1 Jiménez Blas, Felipe
A1 Galindo, Amparo
A1 Vega, Carlos
AB The phase diagram of flexible molecules formed by freely-jointed tangent spheres is studied using the first-order thermodynamic perturbation theory of Wertheim for both fluid and solid phases. A mean-field term is added to the free energy of the fluid and solid phase in order to account for attractive dispersion forces. The approach is used to determine the global (solid– liquid–vapour) phase diagrams and triple points of chain molecules of increasing chain length. It is found that the triple point temperature is not affected strongly by the length of the chain, whereas the gas–liquid critical temperature increases dramatically. The asymptotic limits of the phase diagram for infinitely long chains are discussed. The reduced critical temperature of infinitely long chains as given by the mean-field theory is 2/3, and the reduced triple point temperature is 0.04856, so that an asymptotic value of Tt /Tc = 0.07284 for the ratio of the triple to critical point temperatures is obtained. This indicates that fully-flexible tangent chains present an enormous liquid range. The proposed theory, while being extremely simple, provides a useful insight into the phase behaviour of chain molecules, showing the existence of finite asymptotic limits for the triple and critical point temperatures. However, since n-alkanes present an asymptotic limit of about Tt/Tc = 0.40, the agreement with experiment is not quantitative. This suggests that fully flexible models may not be appropriate to model the solid phases of real chain molecules.
PB Taylor and Francis
SN 0026-8976
SN 1362-3028 (electrónico)
YR 2003
FD 2003
LK http://hdl.handle.net/10272/17636
UL http://hdl.handle.net/10272/17636
LA eng
NO Blas, F. J., Galindo, A. y Vega, C.: "Study of the solid–liquid–vapour phase equilibria of flexible chain molecules using Wertheim’s thermodynamic perturbation theory", Molecular Physics 101, 449-458 (2003). DOI: 10.1080/0026897021000043981
NO Financial support is due to project number BFM- 2001-1420-C02-01 and BFM-2001-1420-C02-02 of the Spanish DGICYT (Dirección General de Investigación Científica y Técnica). FJB would like to acknowledge the Universidad de Huelva and Junta de Andalucía for additional financial support. AG would like to thank the Engineering and Physical Sciences Research Council (EPSRC) for the award of an Advanced Research Fellowship.
DS Repositorio Institucional de la Universidad de Huelva
RD 14 jul 2026