The pupils add approximately 2 mL of heptanol and three boiling chips to a test tube containing a mixture of 3 mL of concentrated acetic acid and 0.5 mL of concentrated sulphuric acid, using a pipette fitted with a Pileus ball. The test tube is then sealed with the stopper and rising tube and clamped into a test tube holder
. The hot-air blower is placed upright on the student experiment bench and switched on. The test tube is now held at an angle in the hot-air stream for short intervals of 10–20 s at a time, whilst being shaken gently. This procedure is repeated twice, after approximately 30 s each time.
Clean-up:
Once the test tube has cooled to room temperature, the reaction mixture is carefully poured into the beaker, which has been pre-filled with 20 mL of cold water. After one minute, the contents of the beaker can be poured back into the test tube. The resulting ester separates as a water-clear oily phase above the aqueous phase.

Notes:

The aqueous acid solution can be coloured by adding a drop of the indicator methyl orange. The phase boundary between the ester and the aqueous phase, which has been coloured red, is then easier to recognise. Alternatively, it is possible to neutralise the aqueous phase before separating the ester by adding magnesium oxide, causing the colour to change from red to yellow.

This method is suitable for the combinatorial synthesis of 1-alkyl alkanoates. The quantities must be adjusted in accordance with the molar masses of the starting materials.

Test tube rack,
test tube (with rim),
50 mL beaker,
test tube holder,
rubber stopper with rising tube (l = approx. 20 cm),

pipette with Pileus ball

Pasteur pipette,

Hot-air blower (e.g. Steinel HL 1810 S),
boiling stones,

Disposable gloves,

Safety goggles