50cm pear-shaped flask reflux + Bunsen separating funnel.
Procedure |
Reason |
Result |
1. add to the flask 9g of 2hobenzoic acid, 15cm methanol, 2cm conc. sulphuric acid, reflux about an hour. |
hoacid+ methanol>oil of wintergreen + water, acid is catalyst in esterification |
<>-CO2CH3 <>-OH is formed |
2. cool mixture to room temp. and pour into a separating funnel containing 30cm cold water, rinse flask with some ethylethanoate solvent, shake the funnel and allow to settle. |
to wash away aqueous impurities. When rinsing open the tap occasionally to release pressure. Ethylethanoate is used to collect all product. Called solvent extraction. If the mixture contains crystals filter! |
to layers form, upper is organic that we want, lower is water. |
3. run lower layer to the conical flask (don't throw away yet), wash the organic with 30cm 0.5M NaCO3 |
Neutralise the acid, release the pressure often! Organic acid left is now on solvent. U can let the lower layer go. |
No more benzoic acid left |
4. Dry with anhydrous sodium sulphate and filter under gravity. |
Get rid of all the water that remains on solid sulphate. Allow to stay overnight. Don't use Buckner as it would remove H2O from sulphate |
dry oil of wintergreen |
5. distillate collecting everything above 220C |
heat in water-bath to remove all organic impurities |
pure product, distinctive smell. |
6. Calculate the yield |
mark also the flask |
useful product for next react |