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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