In a beaker 20 g of mandelic acid is dissolved in 30 g of ethanol and 1.5 mL of conc. sulfuric acid is added with stirring, the solution is left to stand for 5 days in a dark place. Thereafter evaporate the ethanol off, pour the solution to 75 mL of water and discard the aqueous layer. Wash the organic layer with 50 mL of dilute sodium bicarbonate solution to neutralize and then with 50 mL of water. Further ethyl mandelate may be recovered from the discarded waters with DCM. Distil the crude product in a vacuum (2 mmHg) at 103-105°C.
Washing the mixture
The pure product