Abstract
In reducing experimental vapour–liquid equilibrium data it is common to calculate the Gibbs energy of mixing in excess of that for a solution whose entropy of mixing is given by one of two expressions; ideal entropy or Flory–Huggins entropy. The first of these is proper for a mixture of small molecules of similar size and the second one is proper for a mixture of monomer and chain polymer. This paper considers intermediate cases where there are significant differences in molecular shape as well as size. An expression is derived for the combinatorial entropy of mixing; this expression has Flory's result as the leading term but also contains corrections for molecular bulkiness. The combinatorial entropy of mixing depends on characteristic parameters reflecting both molecular size and shape. Methods are given for simple evaluation of these parameters and illustrations for representative mixtures are presented. In some case, the corrections for bulkiness can be very large.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
