Name: Chemical Reactions of Ethers: Nucleophilic Substitution
Uploaded: 2019-07-19
Duration: 4 min 9 s
Description: This video illustrates the chemical reactions of ethers. In the presence of strong acids, ethers undergo nucleophilic substitution reactions to give alkyl ha...

Question

How is diethyl ether prepared in the laboratory? How will you distinguish it from ethanol and diphenyl ether? What happens when it is treated with hot

HI

?

Accepted Answer

Preparation of diethyl ether in the laboratory: In this method, diethyl ether is synthesised by the reaction of ethanol with excess of concentrated sulphuric acid at $413 K$ temperature.

$2 C_{2} H_{5} OH \to_{413 K}^{Con . H_{2} {SO}_{4}} C_{2} H_{5} - O - C_{2} H_{5} + H_{2} O$

Procedure: Ethyl alcohol is taken in distillation flask (two volume), to this concentrated $H_{2} {SO}_{4}$ (one volume) is added slowly. Flask is heated on sand bath at $413 K$ temperature, diethyl ether start forming which is collected in a receiver kept in ice. By the addition of ethanol with the help of dropping funnel, in distillation flask, ether is prepared continuously. The experimental set up is as shown below:

Test to distinguish between diethyl ether and ethanol:

Ethanol is weakly acidic, and reacts with sodium metal to form sodium ethoxide and hydrogen gas. But, diethyl ether does not react with sodium metal.

$2 C_{2} H_{5} OH + 2 Na \overset{}{\to} 2 C_{2} H_{5} ONa + H_{2}$

$C_{2} H_{5} - O - C_{2} H_{5} + Na \overset{}{\to} No reaction$

Test to distinguish between diethyl ether and diphenyl ether:

In diphenyl ether, the $C - O$ bond has some double bond character due to resonance between the lone pair of electrons on the oxygen atom and the $π$ -electrons of carbon atoms of benzene rings directly attached to the oxygen atom. Therefore, diphenyl does not react with hydrogen iodide.

But, Diethyl ether on heating with hydrogen iodide gives the products, ethyl alcohol and ethyl iodide. The reactions can be written as given below:

$C_{2} H_{5} - O - C_{2} H_{5} + HI \overset{}{\to} C_{2} H_{5} OH + C_{2} H_{5} I$

$C_{6} H_{5} - O - C_{6} H_{5} + HI \overset{}{\to} No reaction$

Reaction of diethyl ether with hot $HI$ :

Diethyl ether on heating with excess of hydrogen iodide gives two molecules of ethyl iodide. The reactions can be written as given below:

$C_{2} H_{5} - O - C_{2} H_{5} + 2 HI \overset{373 K}{\to} 2 C_{2} H_{5} I + H_{2} O$

How is diethyl ether prepared in the laboratory? How will you distinguish it from ethanol and diphenyl ether? What happens when it is treated with hot $HI$ ?

Important Questions on Ethers

Learn and Prepare for any exam you want !

How is diethyl ether prepared in the laboratory? How will you distinguish it from ethanol and diphenyl ether? What happens when it is treated with hot HI?

Important Questions on Ethers

Learn and Prepare for any exam you want !

How is diethyl ether prepared in the laboratory? How will you distinguish it from ethanol and diphenyl ether? What happens when it is treated with hot $HI$ ?