1. Higher Chemistry Perfumes – Smelly Chemistry
REVISION
Esters and terpenes
Volatility
NEW LEARNING
Chemistry of terpenes and how they form.

2. Starter Task
S3 Revision

3. Lesson 1: Essential Oils.
Today we will learn to
Describe how essential oils can be extracted from natural materials
We will do this by
Watching a video of a steam distillation.
We will have succeeded if
We can explain how fragrance molecules like terpenes are obtained from natural sources.

4. Essential Oils
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5. Essential Oils
Essential oils are the concentrated extracts of volatile, non-water-soluble aroma compounds from plants.
Essential oils are widely used in perfumes, cosmetic products, cleaning products and as flavourings in foods.
Essential oils are mixtures of organic compounds.
Terpenes are the key components in most essential oils.

6. Modern uses Cosmetics Cleaning Flavours Dentistry Essential oils
Adhesives
Perfumes
Insect
repellents
Medical

7. Steam Distillation

8. Steam Distillation
Steam distillation is one of the methods used to extract essential oils from plants.
Steam passes over the plant and extracts the essential oil.
The mixture evaporates and passes into the condenser.
The essential oil vapour is chilled and collected

9. What do you know?
Unit 2

10. Lesson 2: Terpenes. Today we will learn to
Explain how terpenes are made from isoprene units.
We will do this by
Watching a video of a steam distillation.
We will have succeeded if
We can explain how fragrance molecules like terpenes are obtained from natural sources.

11. Starter Task
S3 Revision

12. Terpenes
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13. Terpenes
Terpenes are components of a wide variety of fruit and floral flavours and aromas.
Terpenes in plants can be oxidised to produce terpenoids responsible for the distinctive aroma of spices.

14. Terpenes
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15. Structure of Terpenes One isoprene unit contains five carbon atoms
Terpenes are unsaturated compounds formed by joining together isoprene (2-methylbuta-1, 3-diene) units.
One isoprene unit contains five carbon atoms

16. Isoprene units can be linked head to tail to form linear terpenes or in rings to form cyclic terpenes.
Limonene is a cyclic terpene found in citrus fruits. It is made of two isoprene units linked in a ring.

17. Β-carotene is a linear terpene found in carrots
Β-carotene is a linear terpene found in carrots. It is made from 8 isoprene units linked head to tail.
Menthol is a cyclic terpenoid – a terpene which has been oxidised. It is found in peppermint and has a distinctive aroma.

18. ConsolidationTask
Complete Quick Test 6 by copying the molecules and drawing the isoprene units in different colours. You have 10 minutes!
S3 Revision

19. Answers
S3 Revision

20. Answers
S3 Revision