## Problems and Solutions

Chapter 8

Solid-Liquid Equilibria

### Textbook Examples:

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08.01
Solubility of Anthracene and Phenanthrene in Benzene

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

08.02
SLE of Different Xylenes in Benzene

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

08.03
SLE of Benzene - Ethanol Using UNIQUAC

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

08.04
SLE in the Ternary Mixture of o-, m- and p-Xylene

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

08.05
SLE of the Eutectic System CCl_{4} - n-Octane With
Solid Phase Transition

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

08.06
Ideal and Real Solubility of Naphthalene in the Mixture
Ethanol - Isooctane

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

08.07
Cryoscopic Constant of Water and Naphthalene

no Mathcad solution required

08.08
SLE of the Non-Eutectic System Anthracene – Phenanthrene

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

08.09
SLE of the System D-Carvoxime - L-Carvoxime With a
Congruent Melting Point

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

08.10
SLE of the Non-Eutectic Mixture Diphenylacetylene -
N,N-Diphenylhydrazine

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

08.11
SLE of the System CCl_{4 }- p-Xylene With a 1:1
Adduct

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

08.12
Ideal and Real Solubility of NaCl, KCl und NH_{4}Cl
in Water (LIQUAC)

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

### Additional Problems:

P08.01
**Solubility of Anthracene and Phenanthrene in Benzene and
Ethanol (Ideal and Modified UNIFAC)**

Calculate the solubility of the isomeric compounds anthracene and
phenanthrene in benzene and ethanol at 25 °C assuming ideal behavior and
using the group contribution method modified UNIFAC.

Pure component properties:

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

P08.02
**C****ryoscopic Constants
of Benzene and Camphor**

Calculate the cryoscopic constants of
benzene and camphor using the following pure component data:

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

P08.03 **Freezing Point Depression of
Naphthalene Using the Cryoscopic Constant**

Calculate the
freezing point depression of naphthalene for the case that 0.2 g of
benzene is added to 50 g naphthalene. (K_{cry,naphthalene }=
6.96 K kg/mol, M = 128.173 g/mol)

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

P08.04
**Molar Mass from Freezing Point Depression **

Calculate the molar mass of an unknown component which leads to a
freezing point depression of 0.223 K of naphthalene, when 0.25 g of the
unknown compound is added to 100 g naphthalene. (K_{cry,naphthalene} = 6.96 K kg/mol)

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

P08.05 **
Mutual Solubility of Two Isomeric Xylenes**

Calculate the solubility of m-xylene (1) in p-xylene (2) and
p-xylene (1) in m-xylene (2) at a temperature of 225 K.

Pure
component properties:

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

P08.06
**SLE of Eutectic Mixtures Using Ideal Behavior and Modified
UNIFAC **

Calculate the SLE diagram for the following binary eutectic
systems 1,2,3-trichlorobenzene –
n-decane and 1,2,4-trichlorobenzene
– n-tetradecane assuming

a) ideal
behavior

b) taking
into account the real behavior using modified UNIFAC

Compare
the results with the published data that can be downloaded from the
textbook page on www.ddbst.com.

Pure
component properties:

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

P08.07
**SLE of a System With 1:1 Compound Formation Assuming Ideal
Behavior **

Calculate the SLE behavior of the system p-toluidine-phenol with
1:1 compound formation assuming ideal behavior, where the melting point
and enthalpy of fusion of the 1:1 compound should be adjusted to get a
reliable description of the SLE behavior. Published data can be
downloaded from the textbook page on www.ddbst.com.

Pure
component properties:

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

P08.08
**Solid CO**_{2}**
Solubility in Propane Using PSRK and VTPR**

Calculate the solubility of solid carbon dioxide in propane with
the help of the group contribution equations of state PSRK and VTPR
assuming simple eutectic behavior. Compare the results with the results
assuming ideal behavior and the experimental data that can be downloaded
from the textbook page on www.ddbst.com. All required parameters can be
found in Appendix A.

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

P08.09
**Enthalpy of Fusion from Solubility Data **

Estimate the enthalpy of fusion of benzene (1) by regressing the
following solubility data of benzene in toluene assuming ideal (g_{1}
= 1) and simple eutectic behavior.

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

P08.10
**SLE of Eutectic and Ideal Ternary Mixture (Xylenes)**

Determine the solid-liquid equilibrium temperature of the ideal
ternary system m-xylene (1) - o-xylene (2) - p-xylene (3) for a
composition of x_{1} = 0.1 and x_{2} = 0.1 with the help
of the melting temperatures and enthalpies of fusion given in Example
8.4 in the textbook. Which component will crystallize?

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

P08.11
**Eutectic Inside Miscibility Gap Possible?**

Is it, at least theoretically, possible that a eutectic binary
mixture with liquid-liquid immiscibility shows a eutectic composition
inside the miscibility gap?

P08.12 **Regression
and Prediction of SLE in DDB/DDBSP**

In the free DDBSP Explorer Version, search for solid-liquid
equilibrium data for the mixture 2-propanol – benzene. Regress both
datasets simultaneously using the Wilson, NRTL and UNIQUAC model.
Compare the performance of the three models. Compare the data to the
results of the predictive methods UNIFAC, mod. UNIFAC and PSRK. Examine
the different graphical representations.

P08.13
**SLE of Sucrose-Water Taking Into Account the Difference in Solid
and Liquid Heat Capacity **

For the calculation of the solubility of sucrose in water Peres
and Macedo (A.M. Peres, E.A. Macedo, Fluid Phase Equilib. 123 (1996), p.
71-95) proposed the following physical property parameters:

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS

P08.14
**Vapor Pressures of Liquid and Solid Non-Eutectic Mixtures**

The vapor pressures of liquid anthracene and phenanthrene can be
described by the Antoine equation using the Antoine parameters given
below. Calculate the vapor-liquid-solid equilibrium (VLSE) along the
solid-liquid saturation curve assuming ideal mixture behavior in the
liquid phase. Melting points and heats of fusion of both components are
given in Example P08.01 above. Compare the vapor-liquid separation
factors to those of an isothermal VLE data set at 220°C (calculate
assuming ideal liquid mixture behavior).

Mathcad (2001) - Solution (zip)

Mathcad (2001) - Solution as XPS