(A) ESTERS, FATS AND OILS HC CHEMISTRY HC CHEMISTRY (A) ESTERS, FATS AND OILS USES OF ESTERS

(A) ESTERS, FATS AND OILS HC CHEMISTRY HC CHEMISTRY (A) ESTERS, FATS AND OILS USES OF ESTERS After completing this lesson you should be able to : Be able to describe that esters have characteristic smells and are used as flavourings and fragrances. Esters are also used as industrial solvents.

Uses of Esters We imitate these smells by manufacturing flavourings. COPY Uses of Esters We imitate these smells by manufacturing flavourings. Esters are also used in perfumes. Esters can also be used as solvents in glues. Polyesters are used to make plasticisers. Methyl ester is a biodiesel.

Tea and Coffee plants Tea is an aromatic beverage commonly prepared by pouring hot or boiling water over cured leaves of the Camellia sinensis, an evergreen shrub native to Asia. Coffea is a genus of flowering plants whose seeds, called coffee beans, are used to make coffee. It is a member of the family Rubiaceae. They are shrubs or small trees native to tropical and southern Africa and tropical Asia.

Uses of esters COPY Ethyl ethanoate is one of a number of solvents used to extract caffeine from coffee and tea. De-caffeinated products produced with ethyl ethanoate are often described on the packaging as "naturally decaffeinated" because ethyl ethanoate is a chemical found naturally in many fruits.

Uses of esters COPY Caffeine (C8H10N4O2) is an example of a class of compounds called alkaloids which are produced by plants. The name alkaloid means “alkali-like”, where alkali is a base and hence refers to these basic properties. Carryout the experiment to extract caffeine from tea.

Uses of esters Caffeine is more soluble in the organic solvent ethyl ethanoate than in water, so we will extract caffeine into the organic solvent to separate it from glucose, tannins, and other water soluble compounds using a separating funnel. The ethyl ethanoate portions can be combined and the ethyl ethanoate removed by evaporation to leave the caffeine .

How much caffeine in Coffee

Uses of esters COPY Esters are oily liquids with generally very pleasant fruity smells and have a range of uses. Many esters are used as flavourings and in perfumes. Natural fruit flavours contain subtle blends of some of the esters in the table below: Esters are also used as non-polar industrial solvents. Name Shortened Structural Formula Odour/Flavour 3-methylbut-1-yl ethanoate CH3COOCH2CH2CH(CH3)CH3 Banana C2H5COOC4H9 Pear drops Methyl Butanoate Pineapple 3-Methylbutyl Butanoate C3H7COOCH2CH(CH3)C2H5 Apple CH3COOC3H7 Pear Ethyl heptanoate Grape, cherry 2-Methylpropyl methanoate Raspberry C3H7COOC5H11 Apricot, Strawberry Benzyl ethanoate CH3COOCH2C6H5 Peach, flowers Ethyl methanoate rum Methyl 2-aminobenzoate C6H4(NH2)COOCH3 Grapes Benzyl butanoate C3H7COOCH2C6H5 Cherry

Uses of esters COPY Factors affecting perfume design e.g. using esters: Designing a perfume - several issues to address by way of design factors. The perfume needs to be a mixture of compounds to give a prolonged perfumery effect. The perfumer chemist has to design the mixture to give a particular fragrance which includes ... the top note - the first fragrant molecule to be released, and the low note, the last molecule to be vapourised.

Mendeleyev's Dream:

Chemistry of Fragrance

History of Fragrance Cleopatra, queen of Egypt, was a shrewd, accomplished woman. Among her talents was expertise at designing perfume. According to the historian Plutarch, when Cleopatra prepared to meet Marc Antony, she dressed like Venus, the goddess of love, and sailed in on a barge bedecked with gold and silver and so redolent with fragrance that "perfumes diffused themselves from the vessel to the shore." By the next day, she had the ruler of the Middle East wrapped around her little finger. Cleopatra doubtlessly knew what science has proven: Of all the senses, the sense of smell is most powerful in exciting passion. Smells are perceived by the brain's limbic system, the same region that's involved in mood and emotion. Aroma and emotion flow like two streams that converge. The art of mixing perfumes goes back at least to ancient Babylon, circa 4000 B.C. Then, as now, the recipe was simple: Fragrance-bearing oils, called essential oils, are dissolved in another substance. The original oils were extracted from herbs and spices and tree resin such as frankincense and myrrh. The solvent was animal fat or olive oil. Today, natural oils may be complemented by laboratory-born inventions and dissolved in ethyl alcohol (ethanol). Science has made perfumes more varied and available, but the price can make them seem like a royal luxury. You don't need the riches of a queen, though, to feel like one. In the spirit of the clever Cleopatra, we offer 4 tips for making the most of your favourite potion.

Why will these tips make your fragrance last longer… 1. If you want your fragrances to last longer (Why wouldn't you?), don't store them in your bathroom or other damp, warm places. Heat, light, and humidity will break down the perfume and lessen the quality of the fragrance. (hydrolysis, don’t want to smell like a carboxylic acid now do we!) 2. Rub Vaseline on your pulse points before spraying your perfume to make the scent last longer.  The ointment, which is occlusive, will hold the fragrance to your skin longer than if you were to spray it onto dry skin. (esters are non-polar so you will slow their evaporation with non-polar oils). 3. Apply an unscented lotion before your fragrance. Oily complexions.  retain fragrances longer, so if you have dry skin, use a moisturizer first to help lock in the scent  4. Don't dab the fragrance on your wrists after spraying.  If you rub your wrists together, you'll force the top notes to disappear faster than intended and as a result make your fragrance not last as long. 

Uses of esters COPY Esters are also used as non-polar industrial solvents. Some of the smaller esters are quite volatile and are used as solvents in adhesives, inks and paints – pentyl ethanoate is used in nail varnish for example.