Unit 2: Chapter 9 - Fragrances Flashcards
What are essential oils?
Essential oils are concentrated extracts of the volatile, non-water soluble aroma compounds from plants. They are mixtures of many different compounds.
What does “essential” stand for in essential oils and what should it not be confused with?
The “essence” of the plant. They should not be confused with the “absolutely necessary”, “very important”seen in amino acids.
Are essential oils volatile?
Usually
Are essential oils soluble in water?
No they are insoluble in water.
What are essential oils made of?
A mixture of organic compounds?
What process is used to extract essential oils from plants?
Steam distillation.
How does steam distillation work to extract essential oils from plants?
Steam from a generator is passed through shredded plant material in a heated flask. The volatile essential oils vaporise and are carried over by the steam and condensed. Forming an oily layer on top of the water.
What are essential oils commonly useful for?
They are widely used in perfumes, cosmetic products, cleaning products and as flavourings in foods.
What are the most common compounds found in essential oils?
Terpenes.
What are terpenes?
They are unsaturated compounds (contain double carbon bonds) formed by joining together isoprene (2-methylbuta-1,3-diene) units.
How many carbon and hydrogen atoms are present in an isoprene molecule?
5 carbons and eight hydrogens (C5 H8).
When asked to determine the amount of isoprene molecules in a terpene molecule what is the best method?
Count the amount of carbons as one isoprene molecule contains 5 carbons.
What happens to consumer products if they are oxidised?
Their chemical structure changes, causing the fragrance of the essential oil and sometimes the oxidation can cause the essential oil to become harmful.
What are examples of oxidation in molecules?
- Molecules losing electrons in a reaction.
- Molecules gaining electrons in a reaction.
- Increasing the oxygen to hydrogen ratio in a reaction.
Why can it be different to tell if an terpene molecule has been oxidised?
Terpene molecules can be oxidised by gaining electrons but also by losing hydrogen atoms (See fragrances booklet for example). So it is alway best to compare the hydrogen to oxygen ratio.
