2.6.5.5.2 General Properties of Terpene Phenols
There are several characteristic features of terpene phenols which not only help them in their separation but also aid in their identification as stated below:
1. Bromine Reaction: Phenols react with bromine evolving the corresponding HBr. The resulting bromides are usually crystalline in nature and sparingly water-soluble. Hence, they may be separated easily and identified accordingly.
2. Reaction with Ferric Chloride: Phenols react with dilute aqueous solutions of ferric chloride (FeCl3) (0.1-0.2% w/v) to give rise to intense coloured reactions, which attributes to the specific colour-tests.
3. Formation of Phthaleins: Several phenols react with phthalic anhydride to form their
corresponding phthaleins.
4. Most phenols react with specific reagents, such as: acetic anhydride, benzoyl chloride, phenyl isocyanate and p-nitrobenzoyl chloride to give characteristic reaction products that also help in their identifications.
