In I/GCSE Chemistry, we will learn about Esters – COO group 2E.

• Fruity smell b/c organic
• Low molecular mass + B.P = (molecules evaporate quickly )  good for solvents
• Highly flammable
• Some can hydrolyse back to original reactants
• Acetate is a colourless liquid at room temp.

• Flood flavourings
• Perfumes
• Solvents
• Plasticsers

In I/GCSE Chemistry, Extracting natural esters is too expensive. Instead you can make synthetic “nature identical” esters.

Alcohol + Carboxylic acid [+sulphuric ester catalyst] --> Ester

Refluxing

• Ethanol + Ethanoic acid + conc. Sulfuric acid is in the flask
• Heating speeds up the reaction, although gently so that the ethanol doesn’t evaporate/ catch on fire
• The flask is fitted with a condenser
• The condenser catches the ethanol vapour and recycles it back into the flask
• This enables the chemicals to react

Distillation (separating ester from waste chemicals)

• Reacted mixture is heated below a fractionating column (FC)
• As mixture boils, vapour goes up FC
• When temp. at top of the FC reaches boiling point of ethyl ethanoate, it become a liquid
• The liquid flows through condenser and is collected in a container
• The liquid is impure ethyl ethanoate

Purification

• In I/GCSE Chemistry, The distillate ( liquid collected) is poured into a tap funnel

First part

• The mixture is shaken with the aqueous reagent, sodium carbonate (Na₂SO₃),to remove acidic impurities
• The mixture separates into two layers b/c the ethyl ethanoate doesn’t mix with the water in the sodium carbonate solution
• The top layer is ethyl ethanoate. The lower layer is sodium carbonate solution.
• The lower layer can be tapped off

Drying

• In I/GCSE Chemistry, Water still remains in the solution
• Anhydrous granules of calcium chloride (a drying agent) can absorb the water

Filtration

• The granules/ lumps of calcium chloride can be filtered
• Only pure ethyl ethanoate remains

You got it now!

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