Question

How to convert ethyl alcohol to diethyl ether

Answer 1

There are two ways to make diethyl ether (CH3CH2OCH2CH3) from ethanol (CH3CH2OH). The first and most straightforward is to mix ethanol with a strong acid, typically sulfuric acid, H2SO4. The acid dissociates in the aqueous like environment producing hydronium, H3O+. A hydrogen ion protonates the oxygen atom of ethanol, giving the ethanol molecule a positive charge:
CH3CH2OH + H3O+ → CH3CH2OH2+ + H2O
The nucleophilic oxygen atom of unprotonated ethanol then displaces a water molecule from the protonated ethanol molecule, producing water, a hydrogen ion and diethyl ether.
CH3CH2OH2+ + CH3CH2OH → H2O + H+ + CH3CH2OCH2CH3
The second, as has been pointed out, is the Williamson ether synthesis, though I would like to offer a variation of the them.
First, I would convert ethanol to ethyl bromide. One method for this is to treat ethanol with concentrated sulfuric acid and then add to potassium bromide. This will yield ethyl bromide (CH3CH2-Br).
Next, treat absolute ethanol (100%, aka 200 proof) with sodium metal to generate the alkoxide (CH3CH2-ONa) followed by reaction with ethyl bromide to yield diethyl ether.
CH3CH2OH + Na → CH3CH2-ONa
CH3CH2-ONa + CH3CH2-Br → CH3CH2OCH2CH3

Answer 2

Answer:

Diethyl ether can be obtained by heating ethyl alcohol in concentrated sulfuric acid.

Explanation:

Heating alcohols with concentrated sulfuric acid  or in phosphoric acid results in condensation of of two alcohol molecules along with removal of water molecule to produce an ether.

$2ROH +H_2SO_4\rightarrow ROR+H_2O$

$2C_2H_5OH+H_2SO_4\rightarrow C_2H_5-O-C_2H_5+H_2O$