Intermolecular dehydration
Protonation turns one ethanol OH group into a better leaving group. The oxygen of another ethanol molecule displaces water, and deprotonation gives diethyl ether; stronger dehydration conditions instead favour ethene.
- Reagents
- H2SO4 catalyst
- Conditions
- Controlled heating favouring intermolecular dehydration
- Reaction class
- Intermolecular dehydration
- Equation
- 2CH3CH2OH -> CH3CH2OCH2CH3 + H2O
Overview
Protonation turns one ethanol OH group into a better leaving group. The oxygen of another ethanol molecule displaces water, and deprotonation gives diethyl ether; stronger dehydration conditions instead favour ethene.
Transformation
- Equation
- 2CH3CH2OH -> CH3CH2OCH2CH3 + H2O
- Reactants
- 2 Ethanol
- Products
- Diethyl ether + Water
- Reagents
- H2SO4 catalyst
- Environment
- Controlled heating favouring intermolecular dehydration
- Reaction class
- Intermolecular dehydration
- Mechanism
- acid-catalysed substitution
- Evidence level
- textbook extension
Scope and limitations
- Scope
- Simple primary alcohol; two ethanol molecules supply the ether groups.
- Limitations
- Stronger dehydration conditions favour ethene; mixed alcohols can form several ethers.
Related reactions
- Iodoform reaction: Ethanol → Triiodomethane products
Ethanol is oxidised and cleaved by alkaline iodine to give triiodomethane and methanoate.
- Partial oxidation: Ethanol → Ethanal
Ethanol is oxidised to ethanal.
- Oxidation: Ethanol → Ethanoic acid
Ethanol is oxidised to ethanoic acid.
- Reduction: Ethanal → Ethanol
Ethanal is reduced to ethanol.
- Esterification: Ethanol → Ethyl acetate
Ethanoic acid and ethanol combine reversibly to form ethyl acetate and water.
- Acid hydrolysis: Ethyl acetate → Ethanol
Ethyl acetate and water react reversibly to form ethanoic acid and ethanol.
- Hydration: Ethene → Ethanol
Ethene gives ethanol through hydration.
- Dehydration: Ethanol → Ethene
Ethanol gives ethene through dehydration.
- Hydrolysis: Bromoethane → Ethanol
Hydroxide attacks the saturated carbon bearing bromine while the C-Br bond breaks. This primary-substrate SN2 route replaces bromide with OH and preserves both carbon atoms; aqueous conditions favour this branch over elimination.
- Acid hydrolysis: Ethyl butyrate → Ethanol
Water attack and proton transfers permit the ethoxy fragment to leave as ethanol. Re-forming the carbonyl produces butanoic acid on the other branch.
References
- Organic Chemistry: Preparing EthersJohn McMurry · OpenStax Organic Chemistry · 2023
Supports functional-group chemistry used to curate the linked examples. Checked 2026-09-16; named examples are applications of textbook scope, without claimed experimental yields.