Question

How is ethene prepared from ethanol? Give the reaction involved in it.

Answer 1

Ethene (${\mathrm{CH}}_2={\mathrm{CH}}_2$)

• Ethene is a colourless gas with a pleasent odour.
• Ethene is completely soluble in organic solvents and slightly soluble in water.

Ethanol(${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}$)

• Ethanol is a volatile liquid, with a pungent smell.
• It is used as a solvent in the synthesis of other organic chemicals.
• It is lighter than air.

Preparation of ethene from ethanol.

• Ethanol is heated at a high temperature in the presence of excess concentrated Sulphuric acid$\left({\mathrm{H}}_2{\mathrm{SO}}_4\right)$ which acts as a dehydrating agent.
• At High-temperature water is removed forming ethene.
• The overall reaction is given below.

$\underset{\mathrm{Ethanol}}{{\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}}\stackrel{\mathrm{conc}.\mathrm{Sulphuric}\mathrm{acid}}{\to }\underset{\mathrm{Ethene}}{{\mathrm{CH}}_2={\mathrm{CH}}_2}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}.}$

Therefore, dehydration of ethanol leads to the formation of ethene.