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Download fileVolumetric Properties and Solubility Parameters of Cyclohexane + CO2 Mixtures at High Pressures and Their Modeling with the Sanchez–Lacombe Equation of State
journal contribution
posted on 2017-06-29, 00:00 authored by Michael
L. Williams, James S. Dickmann, John C. Hassler, Erdogan KiranDensities
of mixtures of cyclohexane and carbon dioxide containing
0 to 50 wt % CO2 were determined using a variable-volume
view cell at pressures ranging from 5 to 35 MPa and temperatures
ranging from 313 to 393 K covering a density range from 0.55 to 0.83 g/cm3. The data were modeled with the
Sanchez–Lacombe (S-L) equation of state (EOS). Modeling was
conducted both by treating each mixture as a pseudopure compound and
by using the S-L parameters for the pure components with a composition-
and temperature-dependent interaction parameter. Various thermodynamic
properties for the mixtures such as the isothermal compressibility,
isobaric expansivity, internal pressure, excess volumes, and solubility
parameters were then evaluated. Mixture excess volumes were also determined,
and they were modeled with Redlich–Kister type equations. The
mixture density data were also modeled using the S-L parameters for
pure components and a composition- and temperature-dependent interaction
parameter. Isothermal compressibilities ranged from 0.0008 MPa–1 for pure cyclohexane at 313 K and 35 MPa to 0.013 MPa–1 for the mixture containing 50 wt % CO2 at 393 K and 20 MPa. Isobaric expansivities ranged from 0.0008
K–1 for cyclohexane at 35 MPa and 313 K to 0.0035
K–1 for the 50 wt % CO2 mixture
at 20 MPa and 393 K. Internal pressures ranged from 83.8 MPa for 50
wt % CO2 mixture at 20 MPa and 393 K to 275.5 MPa
for cyclohexane at 35 MPa and 313 K. Solubility parameters ranged
from 16.6 MPa0.5 for cyclohexane at 35 MPa and 313 K to
9.2 MPa0.5 for 50 wt % CO2 mixture at
20 MPa and 393 K. The mixtures showed a high degree of nonideality
with excess volumes ranging from approximately −20 cm3 mol–1 for 50 wt % CO2 mixture
at 20 MPa and 393 K to +2 cm3 mol–1 also
for the 50 wt % CO2 mixture at 20 MPa, but at 313
K.