酯化

物料与用量

• Ethanoic acid — 10 drops
• Ethanol — 10 drops
• Concentrated sulfuric acid — 1 drop in the specimen tube
• Water — about 10 cm³ for the heating bath
• Sodium carbonate solution — 0.5 mol dm⁻³, half a test tube for work-up

仪器装置

• Borosilicate specimen tube
• Dropping pipettes
• 100–250 cm³ beaker for a hot-water bath
• Test tube and rack
• Tongs and eye protection

实验步骤

1. Add the ethanoic acid to the sulfuric acid in the specimen tube, then add the ethanol.
2. Stand the tube upright in a beaker containing about 10 cm³ of water. Heat gently until the water begins to boil, then stop heating.
3. Leave the reaction tube in the hot water for 1 minute, removing it briefly with tongs if the reaction mixture itself starts to boil.
4. Allow the tube to cool before beginning the carbonate work-up.

后处理与分离

1. Pour the cooled mixture into a test tube half-full of 0.5 mol dm⁻³ sodium carbonate solution.
2. Mix carefully; effervescence occurs while residual acids are neutralised.
3. Allow the ester layer to separate. This microscale method does not produce enough purified material for a yield or boiling-point determination.

关键控制条件

• Use eye protection and handle concentrated sulfuric acid and ethanoic acid as corrosive reagents.
• Use a water bath rather than a naked flame around the flammable alcohol and ester.
• Do not smell directly from the tube; if odour is assessed, waft vapour only after the carbonate work-up.