Preparation of simple esters
Required Reagents:
- sulphuric acid
- A range of alcohols
- A range of carboxylic acids
- 3 x boiling tubes
- Large beaker to act as a water bath
- 250cm3
- Beaker with the cold water
- 0-100 °C thermometer
- 10cm3
- Measuring cylinder
- Stirring rod
- Spatula
- Access to kettle
- Mass balance
- Dropping pipette
Procedure:
- Place 1cm3 of methanol and 3g of salicylic acid in a boiling tube. Mix well and carefully add a few drops of conc. sulphuric acid.
- Place the boiling tube in a water bath at about 80°C for five minutes.
- Pour the contents of the boiling tube into a beaker of cold water.
- Carefully smell the ester floating on the water.
- Place 1cm3 of ethanol and 1cm3 of ethanoic acid in a boiling tube. Mix well and carefully add a few drops of conc. sulphuric acid.
- Repeat steps 2 – 4.
- Try other alcohol/carboxylic acid combinations.
Result:
A fruity smell will be observed indicating the presence of esters. Further identification tests can be conducted for confirmation.