Effect of the structure of the molecule on the properties of a selective solvent

Summary

• 1. The introduction of a functional group into the composition of a solvent molecule results in a decrease in the dissolving capacity of the solvent, particularly for the introduction of a functional group which is capable of forming a hydrogen bond.

• 2. For the same hydrocarbon radical, the higher the dipole moment the greater the selectivity of the solvent. The functional groups have the following order with respect to their effect on the selectivity: NO₂, CN > CHO > COOH > OH > NH₂.

• 3. For a constant radical, the hydrogenation of the carbonyl group of the aldehyde to form the CH₂OH group results in a decrease in the selectivity and dissolving capacity which can be explained by the decrease in the dipole moment and intensification of the association of the solvent molecules.

• 4. The introduction of a second functional group into an aliphatic radical strongly decreases its dissolving capacity and increases the selectivity of the solvent.