Eugenol can be produced synthetically by the allylation of readily available guaiacol with allyl chloride. It is however invariably prepared from its readily available natural sources. It may be separated from its source essential oils by a relatively simple method.

A. Method I (Steam distillation)

1. Powder 10 g of cloves and soak in 150 ml water for about 30 min.
2. Transfer to a distillation flask, add a few porcelain bits, connect to the distillation assembly and heat on a sand bath and heating mantle at a temperature not exceeding 130°C.
3. Continue distillation until about 75 ml of the distillate is collected. The distillate contains both the condensate of eugenol and water.
4. Transfer the distillate into a separating funnel and add 20 ml of dichloromethane. Shake well to extract eugenol from the eugenol-water suspension.
5. Carefully separate the organic layer without any water. Continue the extraction with 15 ml of the organic solvent two more times and pool the organic layers.
6. Pass it through a bed of anhydrous sodium sulphate and collect in a tared 100 ml conical flask. Rinse the drying agent with another 5 ml of dichloromethane and collect it in the same conical flask.
7. Evaporate to dryness on a water bath and note the yield of the product after cooling in a desiccator.
8. To purify the product dissolve it in 30 ml of diethyl ether and transfer into a separating funnel. Extract with 3 × 10 ml of 5% sodium hydroxide solution.
9. Collect the aqueous layers into a clean 100 ml beaker and add concentrated hydrochloric acid until the pH of the solution is 1 (check with indicator paper).
10. Transfer into a separating funnel and extract with 3 × 10 ml portions of dichloromethane. Evaporate the pooled organic layers in a clean tared dish and note the yield.

Identification

Eugenol being a phenol may be identified by simple chemical tests for phenols.

1. Dissolve 5 drops of eugenol in 10 ml of water. Add 3 drops of ferrous chloride solution. Appearance of a bluish-green colour indicates the presence of eugenol.
2. Take 0.5 g of eugenol in a 50 ml beaker. Add 0.1 g of picric acid, 1 ml of benzene and 9 ml of petroleum ether. Mix well and heat until crystals dissolve. The solution turns orange yellow confirming the presence of eugenol.
3. Dissolve 5 drops of eugenol in 5 ml of ethanol. Add a few drops of ferric chloride solution. A blue colour indicates the presence of a phenol.