Volatile Oils

What are volatile oils?

• AKA essential oils

• Volatile when heated

• At room temp they give off a pungent odour, characteristic to each oil

How are volatile oils used pharmaceutically?

• Flavouring

• Aroma agents

Therapeutically:

• Anti-bacterial agents and bronchodilators in cold cure preparations

• Counter-irritants for the skin in ointments

• Analgesics, anaesthetic and anti-inflammatories particularly for toothache

• Treatment of GI problems in indigestion preparations

What is the largest use of volatile oils

• Cosmetic industry

• Used in the formulation of perfumes and deodorants

How are volatile oils obtained?

From a variety of plant sources using steam distillation

What are volatile oils a mixture of?

Low molecular weight terpenes and phenylpropenes

What is eugenol?

• A phenylpropene component of clove oil

• Similar structure to aspirin

• Analgesic and anti-inflammatory agent which inhibits the COX enzyme

Aim of experiment

Isolate and characterise eugenol from clove oil via infrared spectroscopy

After the addition of ferric chloride to ethanol, what colour was the resulting solution?

Yellow

Following the change in colour after the eugenol is added, what has happened to the ferric ion?

• It has been reduced

• The colour change occurs because Fe³⁺ forms a complex with the phenoxide ion, involving electron donation from the phenol

Looking at your IR spectrum, which of the following statements is true?

A. My sample is pure

B. My sample is contaminated

C. It is not possible to say if my sample is pure

D. My sample has traces of sodium sulphate in it

E. My sample has other compounds present

A. My sample is pure

Looking at your IR spectrum of eugenol, what functional groups occur at approximately 3000 cm-1

A. C-H

B. C-O

C. O-H

D. C-Cl

E. C-Br

A. C-H

To which class of natural product does eugenol belong

A. Phenylpropene

B. Phenylethene

C. Phenylethylamine

D. Phenothiazine

E. Phencyclidine

A. Phenylpropene

Which is the best technique to separate volatile oils

A. NMR spectroscopy

B. UV spectroscopy

C. HPLC

D. TLC

E. Gas chromatography

E. Gas chromatography

• Volatile oils are best separated by GC due to their volatility and thermal stability

Why is a base used in this extraction?

Used to extract acidic molecules e.g. eugenol