je7b00005_si_001.pdf (991.05 kB)
Phase Behavior of Binary Mixtures Containing Succinic Acid or Its Esters
journal contribution
posted on 2017-06-22, 19:14 authored by Emrah Altuntepe, Annika Reinhardt, Joscha Brinkmann, Tom Briesemann, Gabriele Sadowski, Christoph HeldThis work provides
experimental data and thermodynamic modeling
on phase equilibria of binary mixtures that are relevant for esterification
reactions. The components under investigation include water, succinic
acid (SA), ethanol (EtOH), 1-butanol (1-BuOH), and the diesters of
SA, namely, diethyl succinate (DES) and dibutyl succinate (DBS), respectively,
as well as the organic solvents acetonitrile (ACN) and tetrahydrofuran
(THF). Liquid–liquid equilibria (LLE) of water/DBS were measured
at ambient pressure for temperatures between 313 and 353 K. Isobaric
vapor–liquid equilibria (VLE) were measured for the binary
systems ACN/DES, ACN/DBS, 1-BuOH/DBS, and THF/DBS at pressures of
10 or 20 or 30 kPa. Temperature ranges for the isobaric VLE varied
between 300 and 500 K. The measured data and phase equilibria reported
in literature were accurately modeled using perturbed-chain statistical
associating fluid theory (PC-SAFT). For this purpose, pure-component
PC-SAFT parameters, which were not already reported in the literature,
were adjusted to experimental literature pure-component data. Applying
binary interaction parameters allowed precise phase-equilibrium modeling
results of the binary systems under investigation. Two different association
schemes for water were used (“2B” and “4C”).
Both schemes appeared to be suitable to describe phase equilibria
of aqueous mixtures; however, a binary parameter for the Wolbach–Sandler
mixing rule was required for aqueous mixtures modeled with the 4C
scheme. For LLE modeling the 2B scheme was found to give better modeling
results. In general, the 4C association scheme for water yields better
results for mixtures with two self-associating components while the
2B association scheme for water should be preferred if mixtures are
considered with water and a non-self-associating component. Further,
the modeling concept of “induced association” has been
investigated and discussed. Especially for mixtures with esters, which
are of main importance for esterification mixtures, the induced-association
approach turned out to be a more accurate modeling strategy compared
to the nonassociative approach.