Dehydration of alcohols

The production of ethene from ethanol involves a chemical reaction known as dehydration, where water is removed from ethanol to form ethene. It is also classified as an “elimination reaction”.

Reagents and conditions required for a laboratory scale experiment:

• Hot, concentrated sulfuric acid or
• Hot pumice stone (SiO₂ and Al₂O₃)

CH₃CH₂OH  →  CH₂=CH₂ + H₂O

LINK TO RSC PRACTICAL SHEET HERE.

Reagents and conditions used in industry:

• Concentrated sulfuric acid 
• 160 – 170 ^oC

Alkenes are in very high demand as feedstock for many chemical manufacturing industries, including, pharmaceuticals and polymers.

Most alkenes are obtained from the cracking of petroleum fractions.

Making ethene from the dehydration of ethanol is clearly sustainable and more environmentally friendly.
Photosynthesis → Fermentation → Dehydration

6CO₂ + 6 H₂O  →  C₆H₁₂O₆  +  6O₂

C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂

C₂H₅OH  →  C₂H₄  +  H₂O