A general view of all chemical and physical properties of esters. Ass well as their daily use and structure ;)

1. Esters

2. What are esters?
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4. Esters occur naturally, but can be made in the laboratory by reacting an alcohol
with an organic acid. A little sulfuric acid is needed as a catalyst. This is the
general word equation for the reaction:
alcohol + organic acid → ester + water
For example:
methanol + butanoic acid → methyl butanoate + water
The diagram shows how this happens, and where the water comes from:

5. Names of esters
end in –oate.
Naming
Named after alcohol & carboxylic acid from
which they are derived.
O
C
CH3
CH2
ethyl
This part comes from the
alcohol & is named after it
CH3
O
ethanoate
This part from the acid
and is named after it

6. Esterification
Esterification is the reaction of a carboxylic acid and alcohol
in the presence of an acid catalyst to produce an ester.
The main chain of an ester comes from the carboxylic acid,
while the alkyl group in an ester comes from the alcohol.

7. Ester hydrolysis
Breakdown of an ester by water.
Process sped up by catalysis
Can use an acid to catalyse (H2SO4)
Alkali catalysts (e.g. sodium hydroxide) can
also be used but instead of producing
carboxylic acid a carboxylate salt is
formed.
Alkaline hydrolysis goes to completion &
hence is usually preferred.

8. Carboxylic acids can be esterified using
diazomethane:
RCO2H + CH2N2 → RCO2CH3 + N2
Using this diazomethane, mixtures of carboxylic acids
can be converted to their methyl esters in near
quantitative yields, e.g., for analysis by gas
chromatography. The method is useful in specialized
organic synthetic operations but is considered too
expensive for large scale applications.

9. Alcoholysis of acyl chlorides and acid
anhydrides
• Alcohols react with acyl chlorides and acid
anhydrides to give esters:
RCOCl + R'OH → RCO2R' + HCl
(RCO)2O + R'OH → RCO2R' + RCO2H
• The reactions are irreversible simplifying work-up(
refers to the series of manipulations required to isolate
and purify the product of a chemical reaction). Since acyl
chlorides and acid anhydrides also react with water,
anhydrous conditions are preferred. This method is
employed only for laboratory-scale procedures, as it
is expensive.

10. Transesterification
• Involves changing one ester into another one.It is
widely practiced:
RCO2R' + CH3OH → RCO2CH3 + R'OH
Like the hydrolysation, transesterification is catalysed
by acids and bases.
• The reaction is widely used for degrading
triglycerides, e.g. in the production of fatty acid
esters and alcohols. Poly(ethylene terephthalate) is
produced by the transesterification of dimethyl
terephthalate and ethylene glycol:
(C6H4)(CO2CH3)2 + 2 C2H4(OH)2 → 1/n
{(C6H4)(CO2)2(C2H4)}n + 2 CH3OH

11. Carbonylation
Alkenes undergo "hydroesterification" in the
presence of metal carbonyl catalysts. Esters of
propionic acid are produced commercially by this
method:
C2H4 + ROH + CO → C2H5CO2R
The carbonylation of methanol yields methyl formate,
which is the main commercial source of formic acid.
The reaction is catalyzed by sodium methoxide:
CH3OH + CO → CH3O2CH

12. Addition of carboxylic acids to alkenes
• In the presence of palladium-based catalysts, ethylene,
acetic acid, and oxygen react to give vinyl acetate:
C2H4 + CH3CO2H + 1/2 O2 → C2H3O2CCH3 + H2O

13. One of the organic chemical reactions known to ancient man was the
preparation of soaps through a reaction called saponification. Natural soaps
are sodium or potassium salts of fatty acids, originally made by boiling lard
or other animal fat together with lye or potash (potassium hydroxide).
Hydrolysis of the fats and oils occurs, yielding glycerol and crude soap.

14. Bar Soaps
Soap is made by combining lye (sodium hydroxide is
the chemical name) with a liquid and fats and oils.
Once these ingredients are mixed, a chemical reaction
starts to take place. The result of this reaction is soap
and if you've made it right, there isn't any lye left. Just
good clean glycerin rich soap.
Liquid Soaps
The major difference between bar soaps and
liquid soaps is the alkali used to saponify the
oils. All soap, whether hard or liquid, starts with
a simple chemical reaction between oils and an
alkali. With bars soaps, it's sodium hydroxide.
With liquid soaps, it's potassium hydroxide.

15. Odors
and smells
One of the most important physical property of esters is their
variety of smells. They occur naturally in plants and animals.
Small esters, in combination with other volatile compounds,
produce the pleasant aroma of fruits. In general, a symphony of
chemicals is responsible for specific fruity fragrances; however,
very often one single compound plays a leading role. For
example, an artificial pineapple flavor contains more than twenty
ingredients but ethyl butyrate is the major component that
accounts for the pineapple-like aroma and flavor. It is amazing
that so many fragrances and flavors can be prepared by simply
changing the number of carbons and hydrogens.

16. Name
Flavor or Fragrance
Propyl
acetate
Pears
Octyl
acetate
Oranges
Isoamyl
acetate
Banana
Ethyl
Butyrate
Pineapple
Butyl
acetate
Apple
Methyl
transcinnamate
Strawberry

17. Perfumes
Property
Why the property is important?
non-toxic
does not poison the wearer
does not irritate the skin
prevents the wearer from suffering rashes
evaporates easily - very volatile
perfume molecules reach the nose easily
insoluble in water
it is not washed off easily
does not react with water
avoids the perfume reacting with
perspiration

18. Aspirin and Salicylic Acid
Aspirin
-is used to relieve pain and
reduce inflammation
-is an ester of salicylic acid
and acetic acid
Oil of wintergreen
-is used to soothe sore
muscles
-is an ester of salicylic
acid and methanol

19. Bleona Çoba
&
Anxhela
Blloshmi