Oxidation of Alcohols
| Alcohol Type | Mild Oxidation [O] | Further Oxidation [O] |
|---|---|---|
| Primary | Aldehyde (distil immediately) | Carboxylic acid (reflux) |
| Secondary | Ketone | No further oxidation |
| Tertiary | Cannot be oxidised (no C–H on C–OH) | |
💡 Oxidising Agents
Acidified potassium dichromate (K₂Cr₂O₇ / H₂SO₄) is the standard oxidising agent. Colour change: orange → green indicates oxidation has occurred.
Reduction of Carbonyls
- Aldehyde + [H] → Primary alcohol
- Ketone + [H] → Secondary alcohol
- Reducing agent: NaBH₄ (sodium borohydride) - a nucleophilic reducing agent
Oxidation Level
📋 Exam Tip
To get an aldehyde from a primary alcohol, use distillation to remove the product before it can be further oxidised. To get the carboxylic acid, use reflux with excess oxidising agent.