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Starter activity

What’s the most pleasant smell you can think of?

And the most revolting?

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Making and testing perfumes…

Chanel No.5 Advertisement

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Scent facts• Dogs can detect the difference in smell between

non-identical twins AND between identical twins despite the fact they are given the same foods or live in the same environment. (Search Dogs)

• Since Moths lack a nose, they use their antenna for smell. Some male moths can detect a single molecule of a female moth’s sex hormone up to 7 miles (11 km) away. A dozen molecules drives the male crazy!

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Perfume factsOne of the key scents in many male aftershaves is musk, which was originally extracted from glands (called a musk pod) that produce pheromones on the male musk deer. Synthetic forms used now.

In May 1921, when the perfume creator Ernest Beaux presented her with a choice of fragrances, Gabrielle Chanel barely hesitated before choosing the fifth one, which was to become CHANEL N°5.

What Chemicals are in Perfumes? • Aliphatic & Aromatic Esters• Aldehydes & Ketones• Alcohols• Terpenes• Phenols• Nitriles• Lactones• Heterocyclics• Acids• Sulphur compounds

Esters 34%

Alcohols23%

Aldehydes15%

Ketones10%

Musks6%

Hydrocarbons 4%

Other8%

Commercial Fragrances

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Properties of Perfume: Why does a perfume need

these properties?• Volatile

– Low Molecular Weight

– Evaporates easily

• Non-toxic– Will not poison the wearer

• Does not dissolve in water– Prevents sweating it off

• Does not irritate the skin

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How do smells spread out?

Where is the smell coming from and how does it spread out?

9© Boardworks Ltd 20041 of 20 © Boardworks Ltd 200517 of 25

Diffusion occurs in liquids and gases but hardly at all in solids.

What is diffusion?

Diffusion is the movement of particles that allows them to spread out and mix with other particles.

For example, the smell of aftershave or perfume diffuses and is detected by people on the other side of the room.

Use the particle model to explain these facts about diffusion:

Diffusion happens more quickly for gases than for liquids.

Diffusion happens more quickly at warm temperatures than at cooler temperatures.

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Diffusion animation 1

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DiffusionDiffusion is when something travels from an area of high concentration to an area of low concentration. For example, consider the scent from a hamburger…

The “scent particles” from this hamburger are in high

concentration here:

Eventually they will “diffuse” out into this

area of low concentration:

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How do our Olfactory sensors work?

• GAS particles DIFFUSE up our NOSE

• Inside the Nose: A patch of tiny Neurons the size of a postage stamp with cilia

• Molecules bind to the cilia Artificial Nose Video

• Trigger receptors that signal the brain to perceive a smell

• Differently shaped nerve cells recognize different smells because each smell molecule fits into a nerve cell like a lock and key

• Each receptor is encoded with a specific gene - if mutated, certain smells are not recognized

Periodic Table of SmellElements

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Keywordssynthetic This is when liquid particles have

enough energy to turn into gas particles

pungent This means something will not dissolve

diffusion A type of chemical made when an alcohol is mixed with an acid

ester A perfume that ismade using man made chemicals

insoluble A very strong (and unpleasant) smell

evaporate This is the movement of particles from an area of high concentration to an area of low concentration

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Keywordssynthetic A perfume that is

made using man made chemicals

pungent A very strong (and unpleasant) smell

diffusion This is the movement of particles from an area of high concentration to an area of low concentration

ester A type of chemical made when an alcohol is mixed with an acid

insoluble This means something will not dissolve

evaporate This is when liquid particles have enough energy to turn into gas particles

EstersAROMATICS

Found in Fats and Oils

O

CH3 —C—O—

CH3 ester group

What are they?How are they made?Formed when an alcohol reacts with a

carboxylic acid.Very slow reaction, unless! an acid

catalyst used (usually sulfuric acid)A condensation reactionThe condensation reaction between the

hydroxyl group and the carboxylic acid known as esterification.

Reverse reaction = ester hydrolysis

This is why it is a condensation reaction because water is produced!

R

R’C

H2O

+

O H

H O

OR’C

R O

O

+⇋

Definition of a condensation reaction = two molecules reacting to form a larger molecule with the elimination of a small molecule such as water

NamingNamed after alcohol & carboxylic

acid from which they are derived.

Names of esters end in –oate.

CH3C

CH2 O

O

CH3

ethyl ethanoate

this part from the acid and is named after it

this part comes from the alcohol & is named after it - “ol” becomes “yl”

let’s name some

esters!

NAMING ESTERS

NAME THE FOLLOWING ESTERS.

1. Methanol and Methanoic Acid 2. Ethanol and Ethanoic Acid 3. Butan-1-ol and Methanoic Acid 4. Ethanol and Hexanoic Acid

Answers:

Structural formulaAlthough the previous structural formula are the clearest way of showing esters, they can draw out in a shortened form.

ethyl ethanoate

CH3CCH2 O

O

CH3

Either…Or…

CH3C CH2O

O

CH3

In this version the acid part has been

written first

Identify the group attached to the C=O – this is from the acid

The group attached to the –O- is from the alcohol.

Wait! What’s that smell?

• Esters have strong, sweet smells.• Their bouquet is often floral or fruity.• This means they are used in food flavorings &

perfumes.• Also, very good at dissolving organic

compounds so often used as solvents.

ester fragrance

ethyl methanoate raspberries

3-methylbutyl ethanoate pears

ethyl 2-methylbutanoate apples

phenylmethyl ethanoate jasmine

Esters from phenols• -OH group in phenol less reactive

to esterification, requires a more vigorous reagent.

• Use of ethanoic acid in esterification is also known as ethanoylation.

• Ethanoic anhydride is a more vigorous ethanoylating agent

OH

Esters from phenols• Ethanoic anhydride used as it is reactive

but not too dangerous.

• Ethanoyl chloride is much more reactive,

but, also toxic and hazardous to use.

• Ethanoic anhydride & ethanoyl chloride are described as acylating agents

using an acylating agent is the only way to esterify a phenolalcohols can be esterified using acylating agents or by reacting with a carboxylic acid.

CH3

CH

CH2 O

O

CH3

CH2C

CH3 O

O

CH

CH3 O

O

ethyl methanoate

methyl propanoate

methyl methanoate

R

R’C

H2O

+

O H

H O

OR’C

R O

O

+⇌

FORWARD REACTION = condensation reaction, the esterification of an alcohol using acid catalyst under reflux.

REVERSE REACTION = ester hydrolysis, same catalyst works for both forward & reverse reactions.

+

OH

OH- →CH3C

CH2 O

O

CH3

ethyl ethanoate

+

CH2CH3

CH3C-O

O

ethanol

ethanoate ionnot a reaction that exists in equilibrium (unlike using acid catalyst)

Essential Oilscontain Esters

What are 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 flavorings in FOODS.

ESSENTIAL OILS

Essential oils are mixtures of organic compounds. Contain Carbon.

TERPENES are the key components in most essential oils.

The history of essential oils

The benefits of essential oils have been recognized for thousands of years.

Their use is described in the New Testament of the Bible.

They were used in anointing rituals and in HEALING THE SICK.

The history of essential oils

The ancient Egyptians used essential oils for EMBALMING RELIGIOUS RITES and MEDICINAL purposes.

KING TUT’S tomb was found to contain 50 jars of essential oil when it was opened in 1922.

Modern uses

Essential oils

Cosmetics Flavours

Perfumes Medical

Cleaning

Insect repellents

Dentistry Adhesives

What are essential oils? ‘Essential’ refers to the fact that the oil carries the

distinctive essence (SCENT) of the plant.

Concentrated, volatile, non-water soluble aroma compounds extracted from plants.

Contain NO ARTIFICIAL SUBSTANCES, unlike perfumes and fragrance oils.

Essential oils – Chemistry

The distinctive character of an essential oil can be attributed to the functional group present in its key molecule.

Esters, aldehydes, ketones and alcohols are all found in essential oils.

Essential oils containing a significant percentage of esters are antispasmodic.

Oils high in esters have a pronounced sedative effect.

Oils high in esters can often be emotionally uplifting.

Some are analgesic Jasmine, Lavender,

Medicinal Purposes of Essential Oils

Medicinal Purposes

Adaptogenic helps the body adjust to and

deal with stress

Anti-inflammatory, and effective on skin rashes and skin irritations.

Some are good digestive aids Chamomile

MASSAGE THERAPY USING ESSENTIAL OILS

ESSENTIAL OILS: PRESCRIPTION ALTERNATIVES

Essential oils – Perfume

The ester linalyl acetate is found in the essential oil lavender.

This ester is often added to perfumes.

CH3

CCH

CH2CH2

CCH

CH2

O

C

CH3

O

CH3CH3

Linalyl acetate

Essential oils – Cosmetics The essential oil Geraniol is added to some

cosmetics to balance and revitalize the skin.

CH3

CCH

CH2CH2

CCH

CH2OH

CH3CH3

Geraniol

Essential oils – Cleaning

The essential oil known as lemon oil contains the terpene d-limonene.

It is known for its ability to act as a natural solvent

and a cleanser.

CH2

CH2C

CH

CH2

CH

CCH2CH3

CH3

Limonene

(skin of citrus fruits)

Hospital Cleaners Certain essential oils kill bacteria and fungi

including MRSA -Staph and E. coli within 2 minutes of contact.

Essential oils are blended into soaps and shampoos used in hospitals to eradicate deadly ‘super bugs’.

Essential oil – Cold Sores

Melissa oil contains the terpene citral, which is used to combat cold sores.

CH3

CCH

CH2CH2

CCH

CO

HCH3CH3

Citral

Essential oils – Toothpaste & Foot Fungus Treatment

The essential oil Thymol has antiseptic properties.

CH

CHC

C

CHC

CH3

OH

CHCH3 CH3

Thym ol

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 vapor is chilled and collected.

Steam distillation

Essential Oils Safety

Should Always be

Considered