In the laboratory ethoxyethane is prepared by dehydrating ethanol with c.H2SO4 in the ratio of 2:1 at 140C temperature.
The reaction completes in two steps:
1)Formation of ethylhydrogen sulphate at 100C
CH3CH2OH + conc.H2SO4 —-> CH3CH2HSO4 + H2O
2)Formation of diethylether at 140C
CH3CH2HSO4 + CH3CH2OH —-> CH3CH2-O-CH2CH3
2CH3CH2OH + conc.H2SO4 —-> CH3CH2-O-CH2CH3 + H2SO4.H2O
Mixture of ethanol and conc.H2SO4 in the ratio of 2:1 is taken in clean Round Bottom Flask (RBF). The flask is fitted with dropping funnel,thermometer and water condensor which is turn is connected to receiver which is immersed in ice cold water.The flask is gently heated on water bath.At 140C,1 volume of ethanol is added at regular interval of time so that ethoxyethane is recieved in receiver continuously.This process of continuous convertion of alcohol into ether is called continuous etherification.Ether thus obtained contains water,alcohol and SO2 as impurities.
The lab preapred ether is impure and may contain C2H5OH,SO2 and water as impurities.
-Acidic impurities are removed by using dil.NaOH solution.
-The alcohol is removed by using 50% CaCl2 solution.
-To remove soluble salts,the etherial solution is washed with cold water frequently.
-The water is removed by using anh.CaCl2
-Finally,Ether is refined by Redistillation process carried out at about 34C to 36C (Since BPT of diethylether is about 35C)