Iodoform reaction
Methyl secondary alcohols are oxidised to methyl ketones, then cleaved to triiodomethane and a one-carbon-shorter carboxylate.
- Reagents
- I2(aq), NaOH(aq)
- Conditions
- warm gently
- Reaction class
- iodoform reaction
- Equation
- CH3CH(OH)R + 4 I2 + 6 OH- -> RCO2- + CHI3 + 5 I- + 5 H2O
Overview
Methyl secondary alcohols are oxidised to methyl ketones, then cleaved to triiodomethane and a one-carbon-shorter carboxylate.
Transformation
Methyl secondary alcohols → Triiodomethane products
- Equation
- CH3CH(OH)R + 4 I2 + 6 OH- -> RCO2- + CHI3 + 5 I- + 5 H2O
- Reagents
- I2(aq), NaOH(aq)
- Environment
- warm gently
- Reaction class
- iodoform reaction
- Mechanism
- oxidation followed by haloform reaction
- Evidence level
- textbook core
Scope and limitations
- Scope
- Secondary alcohols with the CH3CH(OH)R motif give the iodoform reaction after oxidation to methyl ketones.
- Limitations
- Secondary alcohols without the methyl carbinol motif are excluded from this route.
Related reactions
- Iodoform reaction: Methyl ketones → Triiodomethane products
Alkaline iodine converts methyl ketones into yellow triiodomethane and a carboxylate with one fewer carbon.
- Iodoform reaction: Ethanal → Triiodomethane products
Ethanal gives triiodomethane and methanoate in the alkaline iodine iodoform reaction.
- Iodoform reaction: Ethanol → Triiodomethane products
Ethanol is oxidised and cleaved by alkaline iodine to give triiodomethane and methanoate.
References
- Pearson Edexcel Level 3 Advanced GCE in Chemistry specificationPearson Education Limited · Pearson qualifications · 2024
Supports the textbook-core organic reaction routes used for displayed route and mechanism content.