Faculty of Biotechnology
Organic Chemistry
Chapter 3
Reactions
Dr. M. Abd-Elhakeem
Condensation
Is a Chemical reaction in which
two molecules or (functional
groups) combine to form one
single molecule, together with the
loss of a small molecule. Usually
water molecule.
Most common condensation reaction
occurs between Carbonyl group and amino
group such as condensation between two
amino acids to form peptide.
Condensation between hydrazine hydrate or
phenyl hydrazine with aldehydes and ketones
to form characteristic hydrazones and with
di carbonyl compound to form heterocyclic
ring.
Also reaction of alcohols and acids which
known as esterification is considered a
condensation process because it involves a
production of water molecule
Hydrolysis
is a chemical process in which a
certain molecule is split into two
parts by the addition of a Molecule
of water.
Esters and amides shows hydrolysis reactions
as illustrated below
O
CH3
H3C
+
O
H3C
OH
H2O
HO
O
+
O
H
CH3
+
CH3
OH
H3C
O
NH CH3
H3C
OH
+ H2O
O
H3C
+
O
H2N
CH3
Hydrolysis reactions are very important for
our life, where many process in our body
involve hydrolysis step such as
•1- Hydrolysis of ATP (energy source of
human cell) to form ADP and phosphate
group that cause releasing energy
- H2O
+ H2O
2- Hydrolysis of proteins, fats, oils, and
carbohydrates during metabolism to form simple
molecules suitable for absorption.
Polymerization
is a process of reacting Monomers together in a
chemical reaction to form three-dimensional
networks or chains.
Polymers are molecules which consist of a long,
repeating chain of smaller units called monomers.
Polymers have the highest molecular weight
among any molecules, and may consist of billions
of atoms.
Polymer: High molecular weight molecule made
up of a small repeat unit (monomer).
•A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-AA-A-A-A-A
Monomer: Low molecular weight compound that
can be connected together to give a polymer
Oligomer: Short polymer chain
Copolymer: polymer made up of 2 or more
monomers
A-B-B-A-A-B-A-B-A-B-B-B-A-A-B
Polymer Synthesis
There are two major classes of polymer formation
mechanisms
1- Addition polymerization: The polymer grows by
sequential addition of monomers to a reactive site
Addition Polymerization
In*
A
Initiation
In
A*
A
Addition Polymerization
Propagation
In*
A
Initiation
In
A A*
A
Addition Polymerization
A
In*
Initiation
In
A A A*
A
Propagation
Addition Polymerization
A
In*
Initiation
nA
In
A A A A*
Propagation
In
A A A A A*
n
*A
A A A A
m
In
A A A A A
A A A A A
n
Combination
Termination
m
Free-Radical AdditionPolymerization of
Ethylene
H2C
200 °C
2000 atm
CH2
O2
peroxides
polyethylene
2- Condensation polymerization
Condensation polymerization: the polymer grows from
monomers by splitting off a small molecule such as water or
carbon dioxide.
Example: formation of amide links and loss of water
Monomers
First unit of polymer + H2O
Types of Polymers
1- Polyolefins: made from olefin (alkene)
monomers
2- Polyesters, Amides, Urethanes, etc.:
monomers linked by ester, amide, urethane
3- Natural Polymers: Polysaccharides,
DNA, proteins
Common Polyolefins
Monomer
Ethylene
Polymer
Polyethylene
CH3
H3C
n
Repeat unit
CH3
CH3
n
Polypropylene
Propylene
CH3 CH3 CH3 CH3 CH3 CH3 CH3
CH3
Ph
n
Polystyrene
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Styrene
CH3
Cl
n
Poly(vinyl chloride)
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Vinyl Chloride
F2C CF2
Tetrafluoroethylene
F3C
Poly(tetrafluoroethylene): Teflon
F2
C
C
F2
F2
C
C
F2
F2
C
C
F2
F2
C
C
nF
2
F2
C
C
F2
F2
C
C
F2
CF3
Polyesters, Amides, and Urethanes
Monomer
Polymer
O
HO2C
CO2H
Terephthalic
acid
O
OH
HO
Ethylene
glycol
Poly(ethylene terephthalate
n
Ester
O
NH2
OH H2N
4
1,6-Diaminohexane
HO
Nylon 6,6
O
CO2H H2N
HO2C
NH2
1,4-Diamino
benzene
Terephthalic
acid
H2
C
OCN
NCO
4,4-diisocyantophenylmethane
O
HO
H
N
H2
C
H2 H2
O C C O H
HO
O
HO
4
Adipic Acid
O
HO
O
4
N
H
N
4
H
Amide
O
H
N
Kevlar
H
n
H
N H
n
OH
HO
Spandex
Ethylene
glycol
O
H2 H2
H
N
O C C O H
n
Urethane linkage
Natural Polymers
Polymer
Monomer
Polyisoprene:
Natural rubber
Isoprene
n
H OH
H OH
HO
HO
HO
H
OH
H
H
ß-D-glucose
H
OH
Poly(ß-D-glycoside):
cellulose
O
O
Polyamino acid:
protein
R
Amino Acid
O
O
H3N
O
OH
Nucleotide
Base = C, G, T, A
H
Rn+1
n
OH
Rn+2
O
O
O
oligonucleic acid
DNA
n
O
H
N
O P O
Base
OH
OH
H
O
H
N
R1
DNA
O P O
O
HO
H
O
H3N
HO
O
DNA
Base
Type
Abbreviation
Low-density polyethylene LDPE
High-density
Polyethylene
Polypropylene
HDPE
PP
Poly(vinyl chloride)
PVC
Polystyrene
PS
Major Uses
Packaging film, wire and cable insulation,
toys, flexible bottles housewares, coatings
Bottles, drums, pipe, conduit, sheet, film,
wire and cable insulation
Automobile and appliance parts, furniture,
cordage, webbing, carpeting, film packaging
Construction, rigid pipe, flooring, wire
and cable insulation, film and sheet
Packaging (foam and film), foam
insulation appliances, housewares, toys
Type
Abbreviation
Phenol-formaldehyde
PF
Urea-formaldehyde
UF
Unsaturated polyester
UP
Epoxy
-
Melamine-formaldehyde
MF
Typical Uses
Electrical and electronic equipment,
automobile parts, utensil handles,
plywood adhesives, particle board
binder
Similar to PF polymer; also
treatment of textiles, coatings
Construction, automobile parts, boat
hulls, marine accessories,
corrosion-resistant ducting, pipe,
tanks, etc., business equipment
Protective coatings, adhesives,
electrical and electronics
applications, industrial flooring
highway paving materials,
composites
Similar to UF polymers; decorative
panels, counter and table tops,
dinnerware
END OF
Chapter 3