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COSMO-RS Applications
Phase Equilibria and Separations
COSMOlogic GmbH & Co. KG
Imbacher Weg 46
D-51379 Leverkusen
Germany
Phone: +49-2171-731-680
Fax: +49-2171-731-689
Email: [email protected]
Web: http://www.cosmologic.de
2 © COSMOlogic
Predicting Properties of Liquids Different Applications Require Different Properties
Properties of interest:
• Activity coefficents
• Phase diagrams: separations and extraction processes
• Partitioning, e.g. Octanol-Water Partition Coefficients
• Solubility in different solvents: solvent design, formulation
• Vapor pressure and boiling point
• Reaction chemistry in solution
Images courtesy of Vichaya Kiatying-Angsulee / FreeDigitalPhotos.net, Stoonn / FreeDigitalPhotos.net, Getideaka / FreeDigitalPhotos.net
3 © COSMOlogic
How ?
Thermodynamic equilibrium properties can be calculated from the chemical potential µ:
„Chemical potentials are important in many aspects of equilibrium chemistry, including melting, boiling, evaporation, solubility, osmosis, partition coefficient, liquid-liquid extraction and chromatography. In each case there is a characteristic constant which is a function of the chemical potentials of the species at equilibrium.”
[http://en.wikipedia.org/wiki/Chemical_potential]
→ COSMO-RS calculates chemical potentials from molecular surface charges s.
ln 𝑝𝑟𝑜𝑝𝑒𝑟𝑡𝑦 ~ Δ𝜇
Predicting Properties of Liquids
4 © COSMOlogic
Predicting Properties of Liquids
From µ to properties
Property µ1 µ2
activity coefficient Infinite dilution
Pure compound
vapor pressure Gas phase Pure bulk compound
Partition coefficient Phase 1 Phase 2
Liquid-liquid phase equilibrium
Phase 1 Phase 2
𝛾𝑆𝑋 = exp (𝜇𝑆
𝑋 − 𝜇𝑋𝑋) 𝑅𝑇
𝑝𝑋𝑋 = exp −(𝜇𝑔𝑎𝑠
𝑋 − 𝜇𝑋𝑋) 𝑅𝑇
log𝑃𝑂𝑊 = log10 exp (𝜇𝑊𝑋 − 𝜇𝑂
𝑋) 𝑅𝑇 𝑐𝑂𝑐𝑊
𝜇𝑆𝑋𝑖1
+ 𝑅𝑇ln𝑥𝑋𝑖1 = 𝜇𝑆
𝑋𝑖2
+ 𝑅𝑇ln𝑥𝑋𝑖2
5 © COSMOlogic
Range of Applications What properties do users predict with COSMO-RS?
Straightforward properties (directly calculated by the COSMOtherm program):
• Solvent design in formulation and process engineering: solubility, cocrystals
• Process design involving ionic compounds, in particular Ionic Liquids
• Partition: from simple logKOW and cHenry to complex multiphase extraction equilibria
• Binary, ternary and higher-dimensional phase diagrams: VLE, LLE, SLE
• Activity coefficients, Free Energies and Enthalpies of mixtures and phase transitions
• Vapor pressures of pure compounds and mixtures
• Solubility of crystalline compounds (drugs, dyes, ...)
• Isomer differences, treatment of conformers and tautomers
Advanced applications (involving COSMO-RS plus QSPR and/or quantum chemistry):
• Reaction design and pKa, logD
• Interfacial tension (IFT)
• Solubility and phase equilibrium in polymers
• Physiological partitioning / ADME, adhesion/adsorption to complex matrices
6 © COSMOlogic
Phase Separations Activity coefficients and Partition
Computation of activity coefficients and solvent partition properties
• The activity coefficient gSX of solute X in solvent S at infinite dilution is defined as
• The distribution (partition) coefficient of solute X between solvents 1-octanol and
water is defined as:
• The calculation of the partition coefficient logPOW is accomplished via computation of
mXW and mO
X in infinite dilution in the two solvents:
)/RTμ(μγ X
X
X
S
X
S exp
in water solute ofion concentrat
octanol-1in soluteofionconcentratOWP
O
WX
O
X
WOWV
V)/RTμ(μP exploglog 10
7 © COSMOlogic
Phase Separations Activity coefficients and Partition
Example: Room temperature activity coefficients g of organics in water*
-5
0
5
10
15
-5 0 5 10 15
Calculated
Ex
pe
rim
en
t
*Data set and exp. values: B. Mitchell, P. Jurs, J. Chem. Inf. Comput. Sci. 38 (1998), 200-209.
N = 240 (functionally diverse organic solvents, all liquid)
RMSE = 0.75
8 © COSMOlogic
Phase Separations Activity coefficients and Partition
Air-Solvent partition behavior of 18 refrigerants*: LS = RTrS/HSMS
HS = Henry Coeff.
MS = Mol. Weight
rS = Density
S = Solvent
A priori prediction
by COSMOtherm !
No experimental
vapor pressure data
was used !
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
-3.0 -2.0 -1.0 0.0 1.0 2.0 3.0
Calculated
Ex
pe
rim
en
t
logL (air - water - 298 K)
logL (air - water - 310 K)
logL (air - 1-octanol wet - 298 K)
logL (air - 1-octanol dry - 298 K)
logL (air - NMP dry - 298 K)
logL (air - DMF dry - 298 K)
logL (air - n-nonane - 298 K)
* Exp. Data: M. H.Abraham, J. M. R. Gola, J. E. Cometto-Muniz and W. S. Cain, Fluid Phase Equilibria 180 (2001) 41.
Overall RMSE = 0.31 log10(LS)
9 © COSMOlogic
Phase Separations Activity coefficients and Partition
Solvent-Water partition behavior of 18 refrigerants at T = 298 K*:
logPS =
logLS - logLWater
Full a priori predictions by COSMOtherm !
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Calculated
Ex
pe
rim
en
t
logP (octanol wet - water)
logP (octanol dry - water)
logP (NMP dry - water)
logP (DMF dry - water)
logP (n-nonane dry - water)
* Exp. Data: M. H.Abraham, J. M. R. Gola, J. E. Cometto-Muniz and W. S. Cain, Fluid Phase Equilibria 180 (2001) 41.
Overall RMSE = 0.33 log10(PS)
10 © COSMOlogic
Phase Separations Activity coefficients and Partition
1-Octanol-Water partition of 20 refrigerants / 32 EPA priority pollutants
COSMOtherm RMSE = 0.14 log10(POW) RMSE = 0.27 log10(POW)
MCM RMSE = 0.43 log10(POW) RMSE = 0.15 log10(POW)
KOW-UNIFAC (values missing due to missing group interaction parameters) RMSE = 0.28 log10(POW)
ClogP RMSE = 0.14 log10(POW)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Calculated
Exp
eri
men
t
COSMOtherm
MCM
-1
1
2
3
4
5
6
7
-1 1 2 3 4 5 6 7
Calculated
Ex
pe
rim
en
t
COSMOtherm
MCM
KOW-UNIFAC
ClogP
hexachlorobenzene
logPOW logPOW
* Experimental Data, MCM (Multipole Corrected Group Contribution Solvation Model), KOW-UNIFAC and ClogP predictions taken from:
S.I. Sandler, S.-T. Lin and A. K. Sum, Fluid Phase Equilibria 199 (2002) 5-20.
11 © COSMOlogic
Phase Separations Activity coefficients and Partition
Example: 1-Octanol-Water partition of some organic solvents*
Octanol-Water partition coefficients logPOW
-3
-2
-1
0
1
2
3
4
5
-3 -2 -1 0 1 2 3 4 5
Calculated
Ex
pe
rim
en
t
*Exp. Data: Chuman et al. , Analytical Sciences, 18, (2002) 1015-1020.
N= 148
RMSE=0.43
12 © COSMOlogic
Phase Separations Activity coefficients and Partition
Solubility of refrigerants in compressor oils :
- Modern hydrofluorocarbon refrigerants (HFCs) in heat pumps and refrigeration
require special compressor oils: Polyol Esters (POEs).
- Solubility of the HFC in the oil is the critical property for refrigeration.
- Experimental data is costly and rare
O
O
O
OR1
O
OR1
O
R1
O R1
Pentaerythritoltetrahexanoate (PEC6): R1 =
Pentaerythritoltetranonanoate (PEC9): R1 =
Pentaerythritoltetra-2-ethylbutanoate (PEB6): R1 =
Pentaerythritoltetrapentanoate (PEC5): R1 =
Pentaerythritoltetra-2-ethylhexanoate (PEB8): R1 =
COSMOtherm prediction is valuable !
13 © COSMOlogic
Phase Separations Activity coefficients and Partition
Example: Activity coefficients of refrigerants in compressor oils*
ln(g*) in POE mixture EMKARATE RL 32S at various temperatures
Activity coefficients calculated with i = 1
RMSE = 0.37
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
-2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0
Calculated
Exp
eri
men
t
R124
R12 = CCl2F2
R22
HFC143a
HFC236ea
R125
HFC134a
R142b
R600a
R600
R290HFC236fa
RE170 = Diethylether
HydrocarbonsHydrofluorocarbonsHydrochlorofluorocarbons
ln(g) in PEC9-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
-0.4 -0.2 0 0.2 0.4Calculated
Exp
eri
men
t
HFC152a
HFC32
HFC134a
HFC125
HFC143a
ln(g) in PEB6-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
-0.6 -0.4 -0.2 0 0.2 0.4Calculated
Exp
eri
men
t
HFC143a
HFC125
HFC32
HFC152aHFC134a
ln(g) in PEB8-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
-0.4 -0.2 0 0.2 0.4Calculated
Exp
eri
men
t
HFC152a
HFC32
HFC134a
HFC125
HFC143a
ln(g) in PEC5-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
-0.5 -0.3 -0.1 0.1 0.3Calculated
Exp
eri
men
t
x=y
303.1 K
323.1 K
343.2 K
363.2 K
HFC152a
HFC32
HFC134a
HFC125
HFC143a
*Experimental Data:
(I) R. Stryjek, S. Bobbo, R. Camporese and C. Zilio, J. Chem. Eng. Data 44 (1999) 568.
(II) A. Wahlström and L. Vamling, J. Chem. Eng. Data 44 (1999) 823 and J. Chem. Eng. Data 45 (2000) 97.
14 © COSMOlogic
Phase Separations Activity coefficients and Partition
Example: Gaseous solubility of refrigerants in compressor oils* :
COSMOtherm prediction of Henry law coeffcients He [MPa].
Henry Law Coeffcients [Mpa] of HFCs
in different POEs at T=333.15 K
0.5
0.7
0.9
1.1
1.3
1.5
1.7
1.9
2.1
2.3
2.5
0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.5
Calculated
Exp
eri
men
t
PEC5
PEC9
PEB6
PEB8
HFC32
HFC143a
HFC125
HFC134a
HFC152a
* Exp. Data: A. Wahlström and L. Vamling, J. Chem. Eng. Data 44 (1999) 823 and J. Chem. Eng. Data 45 (2000) 97.
15 © COSMOlogic
Phase Separations Activity coefficients and Partition
Example: Partition coefficient logP between Ionic Liquid and water*
logP for H2O / 1-butyl-3-methyl-imidazolium+ - PF6
-
-2.0
-1.0
0.0
1.0
2.0
3.0
4.0
-2.0 -1.0 0.0 1.0 2.0 3.0 4.0
COSMOtherm (full prediction)
Ex
pe
rim
en
t
*Exp. Data: J.G. Huddleston, University of Alabama, USA.
Benzene
Toluene
Chlorobenzene
1,4-Dichlorobenzene
1,2,4-Trichlorobenzene
4,4'-Dichlorobiphenyl
Benzoic Acid
p-Toluic Acid
4-Hydroxybenzoic acid
Salicylic Acid
Phthalic Acid
Aniline
Methanol
ethanol
n-propanol
isopropanol
butanol
pentanol
16 © COSMOlogic
Phase Separations Activity coefficients and Partition
Example: Activity coefficients g in solvent Ionic Liquids *
ln(giinf) in [bmpy][BF4] at 314 K
-1
0
1
2
3
4
5
6
7
-1 0 1 2 3 4 5 6Exp.
Ca
lc.
Alkanes Alkenes
Alkylbenzenes Alkohols
Polar Organics Chloromethanes
ln(giinf) rms error = 0.19
* Exp. Data: A. Heintz, D.V. Kulikov and S.P. Verevkin, J. Chem. Eng. Data 46 (2001) 1526 and Chem. Thermodynamics (2002) in press.
17 © COSMOlogic
Phase Separations Activity coefficients and Partition
Highlights: COSMOtherm for activity coefficients and partition
• COSMOtherm can predict activity coefficients and all kinds of partition
coefficients (air-solvent, solvent-solvent) as well as related properties such
as Henry-law coefficients with about the same prediction quality over the
complete range of organic and inorganic chemistry in solution.
• The expectable RMSE accuracy is 0.45 kcal/mol in 𝚫𝛍 which corresponds
to 0.33 log10(partition) or a factor of 2 in a partition property
18 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
COSMOtherm predictions of Vapor-Liquid-Equilibrium (VLE) properties:
• Excess enthalpy HE and excess free enthalpy GE.
• Activity coefficients gSX.
• Partial vapor pressures of the compounds pSX :
• Total vapor pressure of the system pS :
• Concentrations of compounds in the gas phase ySX :
X
S
X
S
X
X
X
S γxpp
X
SS pp
S
X
S
X
S
X
X
X /pγxpy
19 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
COSMOtherm predictions of VLE properties:
pure compounds vapor pressures pxX :
• If possible, experimental data should be used for pxX
• Alternatively, COSMOtherm is able to estimate pxX via
This introduces additional errors into the prediction of VLE !
X
S
X
S
X
X
X
S γxpp
)/kTμ(μp X
X
X
gas
X
X exp
20 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Example: COSMOtherm predictions of VLE properties:
binary mixture of the system n-heptane (1) - 1-butanol (2) at T=50°C*
* Exp. Data: A. Gusovius, Diplomarbeit, TU Darmstadt, Germany, 1997; C. W. Smith and E. W. Engel, J. Amer. Chem. Soc. 51 2660 (1929).
Phase diagram x = mole fraction of 1-butanol in the liquid phase.
y = mole fraction of 1-butanol in the gas phase.
Activity coefficients
21 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Example: COSMOtherm predictions of VLE properties:
binary mixture of the system n-heptane (1) - 1-butanol (2) at T=50°C*
* Exp. Data: A. Gusovius, Diplomarbeit, TU Darmstadt, Germany, 1997; C. W. Smith and E. W. Engel, J. Amer. Chem. Soc. 51 2660 (1929).
Excess enthalpies (HE)
Excess free energies (GE)
Excess entropies (SE, times temperature T)
The experimental data was fitted to a polynomial representation
in order to allow for a comparison on the experimental and
calculated TS-Excess=G Excess-H-Excess values. As is
visible COMSOtherm is able to predict the quite unusual
course of TS-Excess qualitatively correct. Taking into account t
he relatively small absolute values of the excess properties in
this system, the quantitative correlation of experimental and
predicted COSMOtherm values is excellent.
22 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
400
900
1400
1900
2400
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
x1, y1
PV
AP [
kP
a]
HFC32 (1) + HFC143a (2)
T=263.15 K
T=273.15 K
T=283.15 K
T=293.15 K
T=303.15 K
T=313.15 K
0
200
400
600
800
1000
1200
1400
1600
1800
2000
0 0.2 0.4 0.6 0.8 1
x1, y1
PV
AP [
kP
a]
HFC143a (1) + HFC236fa (2)
T=283.11 K
T=298.16 K
T=313.21 K
COSMOtherm is applicable where group contribution methods fail
(because of missing parameters) ! E.g. Fluorinated Solvents (HFC’s)*:
* Exp. Data: [1] C.N. Kim, Y.M. Park, J. Chem. Eng. Data 45 (2000) 34. [2] S. Bobbo, R. Camporese, C. Zillio, J. Chem. Eng. Data 45 (2000) 276.
23 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Example: VLE of hydrofluorocarbon (HFC) solvents*
COSMOtherm is able to predict azeotrope behavior
400
500
600
700
800
900
1000
1100
1200
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
x 1
HFC227ea (1) + R600a (2)
CF3CHFCF3 T=323.15 K
T=313.15 K
T=303.15 K
(I) (II)
* Experimental Data (I) + (II): B.-G. Lee, J.-Y. Park, J. S. Lim and Y.-W. Lee, J. Chem. Eng. Data 45 (2000) 760.
24 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
COSMOtherm predicts azeotropes !
Example: 42 isothermal binary VLE of
common organic solvents (Qualitative
assessment of azeotropic behavior)*
* Exp. Data: R. Taylor, private communication;
Compound A Compound B Experiment UNIFAC COSMOtherm
n-Pentane Ethanol Az Az Az
Cyclohexane 1-Butanol Az Az Az
Ethanol Chlorobenzene Non-Az Az Non-Az
Ethyl Acetate 2-Butanone Az Az Non-Az
2-Butanone Methyl Cyclohexane Az Az Az
Ethanol 1-Propanol Non-Az Non-Az Non-Az
Methanol m-Xylene Non-Az Non-Az Non-Az
Acetone 1-Butanol Non-Az Non-Az Non-Az
Acetone Benzene Non-Az Non-Az Non-Az
Acetone Cyclohexane Az Az Az
Ethyl Acetate 2-Propen-1-ol Non-Az Non-Az Non-Az
2-Propen-1-ol n-Heptane Az Az Az
1-Propanol 2-Butanol Non-Az Non-Az Non-Az
1-Propanol 2-Methyl-1-Propanol Non-Az Non-Az Non-Az
1-Propanol p-Xylene Az Az Az
2-Butanone Fluorobenzene Az Az Az
Methyl cyclopentane 2-Methyl-1-Propanol Az Az Az
Isoprene Ethanol Az Az Az
Isoprene Methanol Az Az Az
n-Hexane 2-Pentanone Non-Az Az Non-Az
Ethanol 1-Butanol Non-Az Non-Az Non-Az
2-Propanol 2-Propen-1-ol Non-Az Non-Az Non-Az
Cyclopentane Methyl Acetate Az Az Az
Methyl Acetate Cyclohexane Az Az Az
2-Butanone 2-Butanol Non-Az Non-Az Non-Az
n-Pentane Benzene Non-Az Non-Az Non-Az
n-Pentane Cyclohexane Non-Az Non-Az Non-Az
Benzene Methyl Cyclohexane Non-Az Non-Az Non-Az
n-Hexane Toluene Non-Az Non-Az Non-Az
n-Heptane Ethylbenzene Non-Az Non-Az Non-Az
Toluene p-Xylene Non-Az Non-Az Non-Az
Methanol 2-Methyl-1-Propanol Non-Az Non-Az Non-Az
Methanol 2-Pentanone Non-Az Non-Az Non-Az
Ethanol 3-Pentanone Az Az Az
2-Propen-1-ol Ethylbenzene Az Non-Az Az
Acetonitrile m-Xylene Non-Az Non-Az Non-Az
Methyl Acetate 1-Propanol Non-Az Non-Az Non-Az
Methyl Acetate Toluene Non-Az Non-Az Non-Az
2-Propanol 1-Butanol Non-Az Non-Az Non-Az
2-Butanone Chlorobenzene Non-Az Non-Az Non-Az
Ethyl Acetate 2-Pentanone Non-Az Non-Az Non-Az
2-Butanol 2-Methyl-1-Propanol Non-Az Non-Az Non-Az
25 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
COSMOtherm predicts azeotropes !
Example: 123 isothermal binary VLE
of common organic and inorganic
solvents*.
Quantitative prediction of activity
coefficients g at the experimental
azeotropic points gi(xAzeo) = p/pi
vap
* Exp. Data: R.D. Lide (Ed.), CRC Handbook of Chemistry and Physics, 2000.
Activity coefficient g at azeotropic point
0
1
2
3
4
5
6
7
8
9
0 1 2 3 4 5 6 7 8 9
Experiment
Ca
lcu
late
d
26 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
COSMOtherm is able to distinguish between isomers where group
contribution methods can not: VLE 1- / 2- / 3-hexyne (1) – octane (2)*,**
0
100
200
300
400
500
600
700
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
x1
HE [
J/m
ol]
1-hexyne
3-hexyne
2/3-hexyne - UNIFAC
1-hexyne UNIFAC
2-hexyne
* Exp. Data taken from: G. Boukais-Belaribi et al. Fluid Phase Equilibria 167, 83 (2000)
** COSMOtherm calculations & detailed discussion: F. Eckert, A. Klamt, AIChE Journal, 48 (2002) 369-385.
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
x1
y1
1-hexyne
2-hexyne3-hexyne
2/3-hexyne UNIFAC
1-hexyne UNIFAC
27 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
COSMOtherm is able to distinguish between isomers where group
contribution methods can not: VLE 1- / 2- / 3-hexyne (1) – octane (2)*,**
* Exp. Data taken from: G. Boukais-Belaribi et al. Fluid Phase Equilibria 167, 83 (2000)
** COSMOtherm calculations & detailed discussion: F. Eckert, A. Klamt, AIChE Journal, 48 (2002) 369-385.
Activity coefficients Excess free energy (GE) Phase diagram x = mole fraction of 1-butanol in the liquid phase.
y = mole fraction of 1-butanol in the gas phase.
The plots show different VLE properties at three different temperatures between T=-10°C and T=+60°C. For all properties the
correspondence between experiment and COSMOtherm calculations is very good, qualitatively as well as quantitatively.
28 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Separation of ethyl cyanoformate from it’s isomer cyanomethyl acetate*
* C. Rose, Lonza Group, Switzerland.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
x1
y 1
COSMO-RS is able to resolve
very small electronic effects due
to isomer differences !
O
ON
O
NO
+
29 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
VLE of ethyl acetate (1) - ethanol (2) at 313.15 K
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
x1
y1
Salt Free Experiment
Salt Free Calculated
3mol% LiCl Experiment
3mol% LiCl Calculated
6mol% LiCl Experiment
6mol% LiCl Calculated
Ionic species can be predicted as well: Salt effect on a VLE*
* Exp. Data: Hideaki Takamatsu, Shuzo Ohe, J. Chem. Eng. Data 48 (2003) 277-279.
30 © COSMOlogic
Phase Separations Process Simulation: VLE, LLE
NIST/COMSEF Industrial Fluid Properties Simulation Challenge
*.
COSMO-RS wins
1st,5th, and 6th IFPSC
(AIChE/NIST) 1st IFPSC: Problem Set 1 Part A
VLE of dimethyl ether (1) and propene (2)
0
5
10
15
-2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0
s [e0/nm²]
am
ou
nt
of
su
rfa
ce
p(
s) dimethylether
propene
Similar s-profiles:
Nearly ideal mixture behavior !
COSMOtherm predictions:
g1= 1.09 g2
= 1.00 at -20°C
g1= 1.10 g2
= 1.03 at 20°C
0
200
400
600
800
1000
1200
0 0.2 0.4 0.6 0.8 1x1
P (
kP
a)
T=-20°C T=+20°C
exp. -20°C exp. +20°C
31 © COSMOlogic
Phase Separations Process Simulation: VLE, LLE
NIST/COMSEF Industrial Fluid Properties Simulation Challenge
*.
1st IFPSC: Problem Set 1 Part B:
VLE of nitroethane (1) and 1-methoxy-2-propanol (2)
Two conformers of (2) with different
polarity have to be taken into account !
COSMO-RS predictions:
Azeotrope for
x1 = 0.920 at 40°C
x1 = 0.935 at 80°C
0
5
10
15
20
-2 -1.6 -1.2 -0.8 -0.4 0 0.4 0.8 1.2 1.6 2
s [e0/nm²]
am
ou
nt
of
su
rfa
ce
p( s
)
(1)
(2a)
(2b)
1
10
100
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1x1
p
calc +40°C exp. +40°C
calc. +80°C exp. +80°C
COSMO-RS wins
1st,5th, and 6th IFPSC
(AIChE/NIST)
32 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
COSMOtherm VLE prediction at critical conditions:
Currently, there is no possibility to predict VLE at extremely high pressures or
temperatures where the gas phase is nonideal and the liquid phase compressible (i.e.
conditions near or beyond the critical point).
Critical systems can be described by a combination of COSMOtherm with
Equation of State (EoS) / mixing rule methodologies. A number of successful
combinations have been reported*
* The following articles describe a combination of COSMOtherm thermodynamics predictions with different EoS/mixing rule methodologies
• Fluid Phase Equilibria 275 (2009) 105-115. http://dx.doi.org/10.1016/j.fluid.2008.09.016
• Chem. Sus. Chem. 2 (2009) 628-631. http://dx.doi.org/10.1002/cssc.200900086
• Fluid Phase Equilibria 275 (2009), 105-115 http://dx.doi.org/10.1016/j.fluid.2008.09.016
• Fluid Phase Equilibria 243, (2006), 183-192 http://dx.doi.org/10.1016/j.fluid.2006.03.007
• Fluid Phase Equilibria 231 (2005), 231-238 http://dx.doi.org/10.1016/j.fluid.2005.01.014
• Ind. Eng. Chem. Res., 2003, 42 (7), pp 1495-1507 http://pubs.acs.org/doi/abs/10.1021/ie0207212
• Chemical Engineering& Technology 25 (2002) 254-258 http://dx.doi.org/10.1002/1521-4125(200203)25:3<254::AID-CEAT254>3.0.CO;2-8
33 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Example: Combination of COSMOtherm with Equation of State (EoS) *
* H. Ikeda, Ryoka Systems Inc., Japan.
)(
)(
bvv
Ta
bv
RTp
iiii
i
ii
b
bxx
RT
b
axbTa lnln
593.0)( g
iibxb
MHV1 Mixing rule:
g is given by COSMOtherm
Soave-Redlich-Kwong (SRK) EoS:
34 © COSMOlogic
* H. Ikeda, Ryoka Systems Inc., Japan. Exp. Data: Barr-David et al., J. Chem. Eng. Data, 4 (1959) 107-121.
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Example: Combination of COSMOtherm with Equation of State (EoS) *
VLE for binary mixture of ethanol(1) - water(2)
at different temperatures
1
10
100
1000
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
x1, y1
Pre
ss
ure
[b
ar]
598.15K 578.15K
548.15K
523.15K
473.15K
423.15K
623.15K
35 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Highlights: COSMOtherm in VLE prediction:
• COSMOtherm is able to predict VLEs of almost arbitrary mixtures
• COSMOtherm is applicable where group contribution methods fail.
• The quality of VLE predictions is essentially that of the activity coefficient
prediction (rms error ~0.33 log10(gSX) units).
• COSMOtherm is able to predict systems that are strongly nonideal (aqueous
systems, salt solutions, ionic liquids) and systems with very subtle, almost
ideal interactions at roughly the same predictional quality !
• Pure compound vapor pressures can also be predicted by COSMOtherm.
However, the use of COSMOtherm pure compound vapor pressures
increases the overall error of VLE predictions
• Critical systems are feasible with a combination of COSMOtherm and an
Equation of Sate method
36 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
COSMOtherm predictions of Liquid-Liquid-Equilibrium (LLE) properties:
• The thermodynamic requirement for phase equilibrium of mixtures with two phases I
and II is
• neglecting fugacity, this reduces to
XiIIXiXi
IXi xfxf ,,,, pTpT
IIXiS
IIXi
IXiS
IXi xx gg
for all species Xi in the mix
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
0.00 0.50 1.00 1.50g1*x1
g2*x
2
LLE
37 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Example LLE: p-xy diagram for binary system SF6 (1) – water (2)*
0
500
1000
1500
2000
2500
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
x1, y1
Va
po
ur
Pre
ss
ure
[k
Pa
]
Vapor
Liquid + Vapour
Liquid
sulfur hexafluoride (1) + water (2) at T=292.85 [K]
LLE: x1' = 0.000057 (Exp. ~0.0001)
x1'' = 0.999512 (Exp. ~0.999)
* Exp. Data: B. Strotmann, K. Fischer and J. Gmehling, J. Chem. Eng. Data 44 (1999) 388.
38 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Example LLE: Ternary Phase Diagram of Vertrel-XF – n- decane – n-hexane at 278 K*
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
GRID
CALCULATED
EXPERIMENT
n-decane (2)n-hexane (3)
VERTREL-XF CF3-CHF-CHF-CF2-CF3 (1)
* Exp. Data: Experimental Data: J. A. Luckmann, J. A. Berberich, D. C. Conrad and B. L. Knutson, Ind. Eng. Chem. Res. 41 (2002) 2792.
39 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Example LLE: Ionic species can be predicted as well: salt effect on a LLE*
1-propanol (1) - water (2) + NaCl (3) at p=100.39 kPa
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
x1
y 1
salt free saturatedExperiment salt free Experiment saturated
*Exp. Data: T.-J. Chou, A. Tanioka, H.-C. Tseng, Ind. Eng. Chem. Res. 37 (1998) 2039.
NaCl saturation: Miscibility gap is predicted !
Salt free mixture:
No Miscibility gap !
40 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Example LLE: phase separation x(T) of alcohols with a Ionic Liquid*
[bmim][PF6]+Alcohols
0
20
40
60
80
100
120
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
x(alcohol)
T [
°C]
1-butanol
propanol
ethanol
* Experimental Data: Kenneth Marsh, University of Canterbury, New Zealand.
41 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Highlights: COSMOtherm in LLE prediction:
• COSMOtherm is able to predict LLEs of arbitrary binary, ternary and higher
dimensional multicomponent mixtures.
• COSMOtherm is applicable where group contribution methods fail.
• COSMOtherm is able to predict LLE properties of ionic liquids with the same
prediction quality as conventional solvents.
42 © COSMOlogic
COSMOtherm predictions of Solid-Liquid-Equilibrium (SLE) properties:
• Thermodynamic requirement for phase equilibrium of a solid and a liquid phase:
• To simulate a solid with COSMO-RS it has to be transformed to a liquid
• One has to virtually melt the solid at Tsol
• This procedure requires the free energy of fusion DGfus(Tsol)
• DGfus(T) typically is computed from experimental data:
Phase Separations Phase Diagrams: VLE, LLE, and SLE
fusionGD ii
iSolid mm
isolid
iS1
iS1 lnx mm RT
)1(melt
fusionfusionT
THG DD
43 © COSMOlogic
Example SLE: simple eutectic of toluene – ethylbenzene (near ideal mixture)*
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Eutectic Point
* Experimental Data: R. Taylor, private communication
44 © COSMOlogic
Example SLE: Deep Eutectic of choline chloride - urea mixtures*
Phase Separations Phase Diagrams: VLE, LLE, and SLE
* Experimental Data:P. Abbott et al. Chem. Commun., 2003, 70–71.
Experiment* Prediction
45 © COSMOlogic
Phase Separations Phase Diagrams: VLE, LLE, and SLE
Highlights: COSMOtherm in SLE prediction:
• COSMOtherm is able to predict SLE’s with simple eutectic.
• Experimental pure compound’s heat of fusion data is required for the prediction.
• COSMOtherm is able to predict highly nonideal SLE’s of deep eutectic systems. The
mixture concentration of the eutectic point is predictded very well. The predictions of
the absolute temperature of the eutectic point however, is somewhat off.
46 © COSMOlogic
COSMO-RS in Process Engineering
COSMOthermCO: COSMO-RS in Process Modeling and Engineering
COSMOthermCO: The COSMOtherm – CAPE OPEN Interface
• Rationale: Make available COSMOtherm calculated properties in
Process Modeling & Engineering software via CAPE-OPEN standard
interface definitions.
• A CAPE-OPEN compliant ICapeThermoPropertyRoutine was developed in
collaboration with Amsterchem (J. van Baten, R. Baur): COSMOthermCO
• The interoperability and CAPE-OPEN compliancy of COSMOthermCO has been
verified with all major Process Modeling & Engineering (PME) programs:
• Aspen+ (Version 2004.1 and later) by AspenTech
• Hysys (2007 Release and later) by AspenTech
• PRO/II (Version 8.0 and later) by SimSci/Invensys
• ProSim and ProSimPlus (2007 Release and later) by Simulis
• COCO-TEA (Version 1.05 and later) by AmsterChem
• ChemSep LITE (Version 5.5 and later) by ChemSep
• gPROMS (2007 Release and later) by PSE
47 © COSMOlogic
COSMO-RS in Process Engineering
COSMOthermCO: Application Example
Pressure dependent Azeotropic Distillation of methanol (1) – acetone (2)
• Simulation in COCO-TEA*, activity coefficients provided by COSMOthermCO
• Distillation Column Unit Operation provided by ChemSep**
* AmsterChem, J. van Baten, R. Baur, 2006, http://www.amsterchem.com.
** ChemSep 5.5, R. Taylor, H. Kooijman, 2006, http://www.chemsep.com.
48 © COSMOlogic
COSMO-RS in Process Engineering
COSMOthermCO: Application Example
Pressure dependent Azeotropic Distillation of methanol (1) – acetone (2)
• Solution of the TEA-FlowSheet*,** with COSMOthermCO g took <1 h on a desktop PC
• Calculated McCabe-Thiele diagrams of the distillation columns:
* AmsterChem, J. van Baten, R. Baur, 2006, http://www.amsterchem.com.
** ChemSep 5.5, R. Taylor, H. Kooijman, 2006, http://www.chemsep.com.
