Edexcel IGCSE Chemistry 复习笔记 4.7.2 Practical: Preparation of Ethyl Ethanoate

Aim:

To prepare a small sample of ethyl ethanoate

Diagram:

The preparation of ethyl ethanoate

Method:

• A mixture of ethanoic acid, ethanol and concentrated sulfuric acid is gently heated by either a water bath or an electric heater (ethanol is flammable, so a Bunsen can’t be used!)
• The ester is then distilled off as soon as it is formed and collected in a separate beaker by condensation
• As esters have low boiling points (they are volatile), they are the first to evaporate from the reaction mixture. Removing them from the mixture by distillation prevents the reverse reaction from occurring

Result:

• The distillate can be smelt to check whether an ester has been produced
• Small quantities of ethanoic acid, sulfuric acid and ethanol can also be collected in the process
• To remove acidic impurities, sodium carbonate solution can be added, until the mixture stops fizzing (no more carbon dioxide is evolved)
• To remove ethanol, calcium chloride solution can be added

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