• Esters are derivative from acids, prepared by the reaction of a
Carboxylic acid and an alcohol.
• A way to distinguish esters from other organic families is by the “COOC”
located within a chemical formula.
• In terms of pH Esters are neutral, or extremely close to neutral (do not
change colour of litmus, phenolphthalein, methyl orange or any other
acid-base indicator).
• Esters are colourless and exist in liquid state at room temperature.
• Polar due to the presence of the carbonyl group (mainly because of the
C=O) and act as hydrogen acceptors, not as donors. This ability to
participate in hydrogen bonding allows for some solubility in water.
• Esters are volatile in nature, more then carboxylic acids
•
Because of their lack of hydrogen-bond-donating ability, esters do not
self-associate.
•
An important fact is that the boiling point, melting point and
solubility of the straight chain isomers of esters are lower than
those of branched chain isomers. The larger the structure gets the
higher the boiling point.
(Not Esters)
Example of a simple
straight chain isomer
• The boiling point
of the simple ester
CH3COOCH2CH3
is 77.1°C
Example of a simple
branched chain
isomer
Branched VS. Straight
Chemical
Boiling point
Ethyl butanoate
121 °C
Ethyl 2methylbutanoate
133 °C

Ester names consist of two words.

Use the alkyl portion of the alcohol name
first.
(The carbon chain NOT double bonded to an oxygen)

The -ic acid ending of the name of the
carboxylic acid is replaced with –ate and
follows the first name.
(The carbon chain that IS double bonded to one OR
MORE oxygen)
Methyl Propanoate
Diester
• Two butyls off the ends
• Proponate in the center
• Dibutyl Propanedioate (Di = two double
bonded oxygens )
Esterification

A condensation reaction
Carboxylic acids are recognized as organic
acids (-COOH)
+
 An alcohol compound recognized as a base by
the (-OH) in it’s formula

→→→
Factors
involved in the reaction: Heat and an
acidic catalyst such as the commonly used H2SO4
Esterification
NOTE: The concentration of water is ALWAYS derived
from the (-OH) in the acid and the (-H) in the alcohol
Solubility in Water
Ester
Formula
Line Drawing
Solubility
(g per
100 mL
of water)
ethyl
HCOOCH2C
methanoate H3
10.5
ethyl
ethanoate
CH3COOCH2
CH3
8.7
ethyl
propanoate
CH3CH2COO
CH2CH3
1.7
In Summary: The longer the carbon chain the less soluble
the ester is.
Polarity Ranking of the Functional Groups(most polar first):
Amide > Acid > Alcohol > Ketone ~ Aldehyde > Amine > Ester > Ether > Alkane
• The polarity of the ester molecules causes them to be attracted to one
another and this intermolecular attraction requires more energy (heat)
for the esters to transfer from a liquid to a gaseous state.
• Polarity also causes the ester molecules to be attracted to positively
charged metal surfaces. As a result, the molecules tend to line up on
the metal surface creating a film, which somewhat acts as a lubricant.
• The polar nature of esters also makes them good solvents, which allows
them to disperse oil products(such as varnish).
• Esters with low molecular weight are commonly used as fragrances and
found in essential oils
Esters in Synthetic Lubricants
The Hatco Corporation
Esters have been used successfully in lubrication
for more than 50 years. For example, esters have
been used exclusively in jet engine lubricants
worldwide due to their unique combination of
low temperature ease of flow with clean high
temperature operation.
Artificial fruit flavours in foods
Esters have been use in all food products
containing artificial flavouring for years. They
create distinct flavours and aromas which is
what often sells the product. Flavours: Orange
– octyl ethanoate, grape- ethly heptanoate,
banana- 3-methlybutyl ethanoate, and etc.
Also used as fruity flavours for foods and drinks
such as milkshakes, ice-cream, chewing gum,
jellies, sweets and cakes.
An industrial use of esters include the production of oils, such as bio diesel. Bio
diesel is made using fatty acids (a carboxylic acid) taken from the seeds of
plants and methanol (an alcohol). Heat and a concentrated acid is then used
to quicken the reaction process. Linolenic acid and methanol are used to
create bio diesel. Linolenic acid is found in vegetable or animal fats. As well as
bio diesel being produce, small amounts of glycerine are also produced.
Condensation is emitted
Hydrolysis



The reverse of Esterification
Ester + Acid → Carboxylic
Acid + Alcohol
Ester + Base → Carboxylic
Acid + Alcohol
Floral and fruity perfumes also contain esters, as
well as air fresheners. When produced properly,
esters have a very pleasant and powerful scent
Saponification is a process that produces soap,
usually from fats. Saponification involves a base
(usually caustic soda NaOH), heat, and the
hydrolysis of esters, to form the sodium salt of a
carboxylate, which we call soap.
R- Carbon chain of
a fatty acid
R’- carbon chain of
an alcohol
Type of
Reaction
Reactant 1 Reactant
2
Sample Reaction
Special
Conditions
Condensati Carboxylic
on
acid
(Dehydratio
n)
Alcohol
Heat and
Concentra
ted acid
Hydrolysis
Water
Heat and
Catalyst
Ester
Delmar. Chemwiki: The dynamic chemistry textbook. Retrieved from
http://chemwiki.ucdavis.edu/Organic_Chemistry/Esters/Nomenclature_of_Esters
Clark, J. (n.d.). Retrieved from
http://www.chemguide.co.uk/organicprops/esters/background.html
Ophardt, C. (n.d.). Retrieved from
http://www.elmhurst.edu/~chm/vchembook/213organicfcgp.html
http://www.vvc.edu/academic/chemistry/Unit%209R%20%20Carboxylic%20Acids.pdf
http://www.perkinelmer.com/pdfs/downloads/APP_FAMEbyGCinB100Biodiesel.p
df
http://chemistryhelp.zohosites.com/Physical-Properties-of-Esters.html