Question

a sample of crude organic product isolated from a reaction is insoluble in boiling toluene (methylbenzene). explain whether toluene would be an appropriate solvent for the recrystallization of the crude product.

Answer 1

The basic theory of the recrystallization process is following :

To remove insoluble impurities; dissolved in a solvent, the solution is filtered to remove the insoluble impurities, and the solvent evaporated to produce the solid compound.

To remove colored impurities do same process with an additional step. The solid is dissolved in a solvent and activated charcoal is added, the solution is filtered as before, and the solvent is evaporated to produce the solid compound.

To remove these impurities by the recrystallization process solvent has

high solubility at high temperatures and low solubility at low temperatures.

Here sample of crude organic product isolated from a reaction which is insoluble in boiling toluene (methylbenzene) means sample is insoluble in toluene. If the solid is not dissolved in this than recrystallization of the solid not possible.