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Esters
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What are esters?
Esters are volatile compounds, meaning that they evaporate
easily, and they have characteristic smells.
For example:
propyl ethanoate smells of pears
butyl butanoate smells of pineapple
methyl butanoate smells of apple.
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Esters
Esters have this function group:
Esters are made from the reaction of a carboxylic acid with
an alcohol:
...which is written as –COO–.
carboxylic acid + alcohol ester + water
+ +CH3COOH C2H5OH H2OCH3COOC2H5
ethanoic acid ethanol ethyl ethanoate water+ +
+ +
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Naming esters
Esters are named after the alcohol and the carboxylic acid
from which they are made. The alcohol gives the first part
of the name, and the carboxylic acid gives the second.
Esters always end in “–anoate”.
ethanoic acid ethanol
ethyl ethanoate
For example:
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Matching carboxylic acids to their esters
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Practising naming esters
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Differentiating between substances
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Why are esters useful?
Esters have many uses:
as food flavourings and
perfumes because they are
volatile and smell pleasant
as plastic packaging because
polyesters are lightweight,
durable and moisture-proof
to make fleece clothing, which
is often made from recycled
polyester bottles
as solvents and plasticizers.
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Using esters
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How are esters made?
Esters are made by reacting a
carboxylic acid with an alcohol.
How could you speed it up?
The reactants could be
heated in order to make
the reaction faster.
However, the reaction is very
slow at room temperature.
A strong acid catalyst such as
sulfuric acid could be added.
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Making esters
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What are the stages in making an ester?
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Glossary
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Anagrams
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