When excess ethyl alcohol (ethanol) is heated with conc. H2SO4 at 1400C, diethyl ether or ethoxyethane is obtained.
CHCHOH + conc.HSO→ CHCHHSO + HO
CHCHHSO + CHCHOH → CHCH-O-CHCH
50 cc of conc. HSO is gradually added with constant shaking to 100 cc of ethyl alcohol kept in the distillation flask. The mixture is heated on the water bath at 1400C. When ether begins to distill over, alcohol is added in the distillation flask from the dropping funnel at nearly the same rate as that of the distillation, the temperature being maintained at 1400C.
The distillate contains ether, ethyl alcohol, water, and sulphur dioxide. It is first washed with dil. NaOH solution and then with water. The upper layer is separated and dried over anhydrous CaCl2. It is then redistilled on a water bath pure ether passes over at 34-350C.