Transcript Topic 20 Organic Chemistry (HL)

20.4 Condensation Reactions
Assessment Statements
 20.4.1 Describe, using equations, the reactions with
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alcohol with carboxylic acids to form esters and state
the uses of esters.
20.4.2 Describe, using equations, the reactions with
amines with carboxylic acids.
20.4.3 Deduce the structures of the polymers formed
in the reactions of alcohols with carboxylic acids.
20.4.4 Deduce the structures of the polymers formed
in the reactions with amines and carboxylic acids.
20.4.5 Outline the economic importance of
condensation reactions
Assessment Statements
 20.4.1 Describe, using equations, the reactions
with alcohol with carboxylic acids to form esters
and state the uses of esters.
 20.4.3 Deduce the structures of the polymers
formed in the reactions of alcohols with
carboxylic acids.
Condensation reactions
 Condensation reactions result from the addition
of two molecules with the elimination of water
molecules.
 IMPORTANT in biological systems (IB biolog
students maybe able to recognise where these are
used).
 An example of a condensation reaction is
ESTERIFICATION.
Carboxylic acid + Alcohol (acid catalyst)  Ester and water
 Most esters have very distinctive smells.
 Generally fruity used as scents for perfumes or
air fresheners and food flavourings
 Also used as painkillers, solvents and anaesthetics
Some Esters
Benzene Structures
 Painkillers such as aspirin include esters
 Alcohols can contain more that one hydroxyl group
(OH) and carboxylic acid groups (COOH) so can
link to form POLYESTERS
Multiple COOH
groups
Multiple OH
groups
Groups can still
undergo
further
esterification
Polyesters
 Dipole/dipole interactions between the polar
chains interact with one another.
 Used in textiles (e,g, shirts) and plastics.
This is TERYLENE
(Dacron) used to
make clothing in
cotton/polyester
blends
Assessment Statements
 20.4.2 Describe, using equations, the reactions
with amines with carboxylic acids.
 20.4.4 Deduce the structures of the polymers
formed in the reactions with amines and
carboxylic acids.
Amines with Carboxylic Acids
Example
Polymerisation Reactions
 Nylons is the polymerisation of amines and
carboxylic acids.
 Same principle as polymerisation of carboxylic
acids and alcohols where the molecules have two
amine groups or two carboxylic acid groups.
 The two monomers each have six carbon chains so it is
called nylon 6,6
The Repeating Unit For Nylon 6,6
Nylon in Industry
 The reactions to form nylon are carried out in a
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vacuum so as to assist in the removal of the released
water (remember, it is a condensation reaction)
Nylon is known as a POLYAMIDE
It is the same link as in PEPTIDE BONDS in
POLYPEPTIDES in PROTEINS.
Nylon is produced in a solid form and can be melted
and passed through jets which produces NYLON
FIBRES.
The resultant product can then be woven for rope,
fabrics, parachutes, bags etc
Hydrogen Bonding
 Hydrogen bonds hold the strands together
between the NH and CO groups.
Further Uses
Assessment Statements
 20.4.5 Outline the economic importance of
condensation reactions
Just to Summarise
 Condensation reactions are used to make
 Perfumes
 Flavourings
 Painkillers
 Solvents
 Anaesthetics
 Plastics (e.g kevlar)
 Polyesters
 Nylons (Polyamides)
 Making Proteins
 The worlds nylon production is estimated to
exceed 5 million tonnes
 Clothes carpets, ropes etc
 High strength, resists abrasion and easy to dye.
 Used in engineering to replace metals (gears, etc)
 Kevlar now used to reinforce many materials.
Diagram of common organic
reactions HL
23