Question

explain the possible advantages of using urea and cinnamic acid for recrystallization and the properties of these solvent are important.

Answer 1

The advantages of using urea and cinnamic acid for recrystallization is to obtain the corresponding pure compounds, i.e. the compounds without any impurity.

Urea: Urea was recrystallized in distilled methanol. The solvent was saturated with urea at 40 ^oC. The solution was filtered to avoid any insoluble impurities by using heated apparatus to prevent nucleation. The solution was cooled down to room temperature, in order to obtain maximum yield. Then the resulted crystals were recrystallized further.

Cinnamic acid: Cinnamic acid is fairly soluble in ethanol but less soluble in water. Initially, ethanol is saturated with cinnamic acid, then add a small amount of water so that the cinnamic acid will crystallize out to obtain the maximum yield.