4.4: Solubility of Vanillin in organic solvents

In this example the solubility of Vanillin in 9 different solvents is calculated and compared to experiment.

Vanillin (4-Hydroxy-3-methoxybenzaldehyde) is a solid at room temperature. For the solubility of a solid, one should include the melting point and the enthalpy of fusion of the solid in the left window of the 'Compounds' window for a selected compound. If known the Δ heat capacity of fusion should also be included, although it is often less important.

Remark: To only add the compounds needed in this example, one can also open a new COSMO-RS GUI window (File → New), copy the $ADFHOME/examples/crs/Tutorial4/tutorial4.4.compoundlist to the directory where the COSMO-RS database is downloaded, and select this file with File → Add Compound(s). The tutorial4.4.compoundlist is a file with a list of compounds that is limited to the coumpounds needed in this example.

Select View → Compounds
Click on the left side 'Vanillin'
Enter '355' in the 'Melting point:' field
Enter '5.35' in the 'Delta H_fusion:' field
Select Properties → Solubility
Select 'Water' for the first component in 'Solvent'
Select 'Vanillin' for the first 'Solute'
Enter '298.15' without quotes in the 'Temperature Kelvin from:' field
Enter '298.15' in the 'to:' field
Select File → Run
Click 'Yes' when asked to 'Save changes (required to run)?'

Note that for the calculation of the solubility in units of mol/L and g/L the program uses information of the mass and COSMO volume of the solvent and solute. Especially the COSMO volume may not always be accurate.

In a similar way as we did the solubility calculation of Vanillin in Water, one can now calculate the solubility of Vanillin in several other solvents.

Select Properties → Solubility
Select '1,2-Dichloroethane' for the first component in 'Solvent'
Select File → Run
Click 'Yes' when asked to 'Save changes (required to run)?'
Do the same for the solvent '1-Propanol', 'Oxolane' (THF), 'Acetonitrile',
'2-Butanone', 'Ethanol', 'Methanol', and 'Toluene'

These results can be put in a table.

Compared to experiment there can easily be a factor of 2 deviation.

References

[441] Experimentally determined solubilities of Vanillin in some organic solvents were taken at July 15, 2010, from http://old.oru.edu/cccda/sl/solubility/allsolvents.php?solute=vanillin.