Alkyne combustion reaction:
2 C2H2 + 5 O2
4 CO2 + 2 H2O
The combustion reactions are all exothermic.
180
Substitution Reactions
181
Substitution Reactions
Reaction with chlorine:
182
Substitution Reactions
Reaction with chlorine:
CH4 + Cl2
CH3Cl + HCl
chloromethane
183
Substitution Reactions
Reaction with chlorine:
CH4 + Cl2
CH3Cl + HCl
chloromethane
CH3Cl + Cl2
CH2Cl2 + HCl
dichloromethane
184
CH2Cl2 + Cl2
CHCl3 + HCl
trichloromethane
185
CH2Cl2 + Cl2
CHCl3 + HCl
trichloromethane
CHCl3 + Cl2
CCl4 + HCl
tetrachloromethane
186
For organic reactions it is common practice to
indicate the reaction conditions. That is, for
the reaction with chlorine:
187
For organic reactions it is common practice to
indicate the reaction conditions. That is, for
the reaction with chlorine:
CH4 + Cl2
CH3Cl + HCl
188
For organic reactions it is common practice to
indicate the reaction conditions. That is, for
the reaction with chlorine:
heat (300 oC)
CH4 + Cl2
CH3Cl + HCl
189
For organic reactions it is common practice to
indicate the reaction conditions. That is, for
the reaction with chlorine:
heat (300 oC)
CH4 + Cl2
CH3Cl + HCl
or uv irrad.
room temp.
190
Addition Reactions
191
Cl2 +
H
H
C C
H
H
dark
25 oC
Cl Cl
H
H
C C
H
H
1,2- dichloroethane
192
CH3CCH + 2 Cl2
propyne
CH3CHCH2 + HBr
propene
CH3CCl2CHCl2
1,1,2,2-tetrachloropropane
CH3CHBrCH3
2-bromopropane
It turns out that when a hydrogen halide add to an
alkene, the more electronegative halogen atom
always tends to end up on the carbon atom of the
double bond that has fewer hydrogen atoms
(Markovnikov’s rule).
193
H2SO4
CH2CH2 + H2O
CH3CH2OH
194
Hydrogenation
The following reaction is an example of
hydrogenation of an alkene, addition of H2
across a double bond.
195
H
H H
H
C
C
H
H
ethene
+ H2
H C
H
C H
H
ethane
196
Functional Group Concept
197
Functional Group Concept
A great many organic molecules have complex
structures.
198
Functional Group Concept
A great many organic molecules have complex
structures. Trying to predict the properties
and possible reactions of a complex structure
can be very difficult.
199
Functional Group Concept
A great many organic molecules have complex
structures. Trying to predict the properties
and possible reactions of a complex structure
can be very difficult. Chemists have found it
very useful to characterize certain well defined
fragments of an organic molecule.
200
Functional Group Concept
A great many organic molecules have complex
structures. Trying to predict the properties
and possible reactions of a complex structure
can be very difficult. Chemists have found it
very useful to characterize certain well defined
fragments of an organic molecule. These
fragments (in isolation) have well defined
reactive capabilities.
201
When these units are found in complex
structures, predictions can be made as to the
likely properties and reactions of the complex
structure.
202
When these units are found in complex
structures, predictions can be made as to the
likely properties and reactions of the complex
structure. These fragment units are called
functional groups.
203
Some common functional groups
Functional
group
formula
Name
Example
IUPAC Name
Common Name
204
Some common functional groups
Functional
group
formula
Name
Example
IUPAC Name
R O
alcohol
CH3OH
methanol
H
Common Name
methyl alcohol
205
Some common functional groups
Functional
group
formula
Name
Example
IUPAC Name
R O
alcohol
CH3OH
methanol
R C
H
O
O
_
carboxylic CH3CO2H
acid
H
ethanoic acid
Common Name
methyl alcohol
acetic acid
206
Some common functional groups
Functional
group
formula
Name
Example
IUPAC Name
R O
alcohol
CH3OH
methanol
R C
H
O
O
_
carboxylic CH3CO2H
acid
H
Common Name
methyl alcohol
ethanoic acid
acetic acid
propanone
acetone
O
R
C R
ketone
CH3COCH3
207
Some common functional groups
Functional
group
formula
Name
Example
IUPAC Name
R O
alcohol
CH3OH
methanol
R C
H
O
O
_
carboxylic CH3CO2H
acid
H
Common Name
methyl alcohol
ethanoic acid
acetic acid
propanone
acetone
O
R
C R
ketone
CH3COCH3
R and R  are alkyl (or more complicated groups). R  cannot be H.
R cannot be H for the alcohol (that would be water!), nor for the
ketone (that would give an aldehyde).
208
Functional
group
formula
Name
Example
IUPAC Name
Common Name
O
R
C
aldehyde
HCHO
methanal
formaldehyde
H
209
Functional
group
formula
Name
Example
IUPAC Name
Common Name
O
R
C
aldehyde
H
R C
O
O
R
HCHO
methanal
formaldehyde
ester CH3CO2CH2CH3 ethyl ethanoate ethyl acetate
210
Functional
group
formula
Name
Example
IUPAC Name
Common Name
O
R
C
aldehyde
H
R C
O
O
R
NH2
R
HCHO
methanal
formaldehyde
ester CH3CO2CH2CH3 ethyl ethanoate ethyl acetate
amine
CH3NH2
aminomethane
methylamine
211
Functional
group
formula
Name
Example
IUPAC Name
Common Name
O
R
C
aldehyde
H
R C
O
O
R
NH2
R
HCHO
methanal
formaldehyde
ester CH3CO2CH2CH3 ethyl ethanoate ethyl acetate
amine
CH3NH2
aminomethane
methylamine
R and R  are alkyl (or more complicated groups). R  cannot be H (that
would give an acid). R cannot be H for the amine (that would be
ammonia!).
212
Functional
group
formula
R
O
R
Name
ether
Example
IUPAC Name
CH3OCH3 methoxymethane
Common Name
dimethyl ether
213
Functional
group
formula
R
R
O
Name
Example
IUPAC Name
ether
CH3OCH3 methoxymethane
amide
CH3CONH2
Common Name
dimethyl ether
O
R C
ethanamide
NH 2
214
Functional
group
formula
R
R
O
Name
Example
IUPAC Name
ether
CH3OCH3 methoxymethane
amide
CH3CONH2
Common Name
dimethyl ether
O
R C
ethanamide
NH 2
R and R  are alkyl (or more complicated groups). R  cannot be H
(that would give an alcohol). R cannot be H for the ether (that would
also give an alcohol).
215
Summary of name endings
216
Summary of name endings
Functional group Parent alkane
name ending
217
Summary of name endings
Functional group Parent alkane
name ending
alcohol
change e
to
ol
218
Summary of name endings
Functional group Parent alkane
name ending
alcohol
change e
to
ol
carboxylic acid
change e
to
oic acid
219
Summary of name endings
Functional group Parent alkane
name ending
alcohol
change e
to
ol
carboxylic acid
change e
to
oic acid
ketone
change e
to
one
220
Summary of name endings
Functional group Parent alkane
alcohol
change e
carboxylic acid
change e
ketone
change e
aldehyde
change e
to
to
to
to
name ending
ol
oic acid
one
al
221
Summary of name endings
Functional group Parent alkane
alcohol
change e
carboxylic acid
change e
ketone
change e
aldehyde
change e
amide
change e
to
to
to
to
to
name ending
ol
oic acid
one
al
amide
222
Summary of name endings
Functional group Parent alkane
alcohol
change e
carboxylic acid
change e
ketone
change e
aldehyde
change e
amide
change e
amine
to
to
to
to
to
name ending
ol
oic acid
one
al
amide
insert amino in front of alkane name
223
Summary of name endings
Functional group Parent alkane
alcohol
change e
carboxylic acid
change e
ketone
change e
aldehyde
change e
amide
change e
amine
ester
to
to
to
to
to
name ending
ol
oic acid
one
al
amide
insert amino in front of alkane name
insert alkyl name then change e to oate
224
Summary of name endings
Functional group Parent alkane
alcohol
change e
carboxylic acid
change e
ketone
change e
aldehyde
change e
amide
change e
amine
ester
ether
to
to
to
to
to
name ending
ol
oic acid
one
al
amide
insert amino in front of alkane name
insert alkyl name then change e to oate
change ane to oxy then add in second
alkane name.
225
Key comment on a functional group
The carboxylic acid is a combination of two
functions groups:
O
C
O
C
O H
carboxylic acid
ketone
plus
O
H
alcohol
226
Key comment on a functional group
The carboxylic acid is a combination of two
functions groups:
O
C
O
C
plus
O H
carboxylic acid
ketone
HOWEVER, a compound such as
O
H
alcohol
227
CH3CH2CCH2CH2 OH
O
would NOT function like a carboxylic acid, but
as an alcohol in some reactions and a ketone
in some other reactions.
228
Comparison of some properties
229
230
231
232
Some simple representative reactions
of a few functional groups.
233
Formation of an ester:
O
CH3
C
+ CH3CH2OH
O H
carboxylic acid
alcohol
O
CH3
C
+ H2O
OCH2CH3
ester
234
Formation of an ester:
O
CH3
C
+ CH3CH2OH
O H
carboxylic acid
alcohol
ethanoic acid ethanol
O
CH3
C
+ H2O
OCH2CH3
ester
ethyl ethanoate
235
Oxidation of an alcohol:
H2SO4,K2Cr2O7
CH3CH2OH
alcohol
warm
236
Oxidation of an alcohol:
H2SO4,K2Cr2O7
CH3CH2OH
alcohol
O
CH3
warm
C
H
aldehyde
237
Oxidation of an alcohol:
H2SO4,K2Cr2O7
CH3CH2OH
alcohol
O
CH3
warm
C
H
aldehyde
further warming
O
carboxylic acid CH3 C
O H
238
Note: In organic reactions, the side products (e.g.
Cr3+ in the preceding reaction) are often not given.
Here is the complete chemical equation:
239
Note: In organic reactions, the side products (e.g.
Cr3+ in the preceding reaction) are often not given.
Here is the complete chemical equation:
16 H+ + 2 Cr2O72- + 3 CH3CH2OH
4 Cr3+ +3CH3CO2H
+ 11 H2O
240
Note: In organic reactions, the side products (e.g.
Cr3+ in the preceding reaction) are often not given.
Here is the complete chemical equation:
16 H+ + 2 Cr2O72- + 3 CH3CH2OH
(orange)
4 Cr3+ +3CH3CO2H
+ 11 H2O
(green)
241
The intermediate reaction would be:
8 H+ + Cr2O72- + 3 CH3CH2OH
(orange)
2 Cr3+ + 3 CH3CHO
+ 7 H2O
(green)
242
Oxidation of an alcohol:
OH
CH3CHCH3
alcohol
H2SO4,K2Cr2O7
or KMnO4
O
CH3CCH3
ketone
243
Aromatic Compounds
244
Aromatic Compounds
Aromatic – from aroma – a number of these
compounds have strong and sometimes
pleasant odors.
245
Aromatic Compounds
Aromatic – from aroma – a number of these
compounds have strong and sometimes
pleasant odors.
The most important compound in this family
is benzene.
246
Benzene C6H6
This is a very important example in organic
chemistry – an example of resonance:
H
H
H
C
C
C
C
H
H
C
C
H
H
H
C
H
C
C
C
C
C
H
H
H
247
The two resonance structures are averaged
leading to the following structure:
H
H
H
C
C
C
C
C
C
H
H
H
248
If resonance were not important for benzene, i.e.
only one of the two preceding resonance
structures were required to describe the structure
of benzene, then we might expect benzene to
have a reactivity similar to
249
If resonance were not important for benzene, i.e.
only one of the two preceding resonance
structures were required to describe the structure
of benzene, then we might expect benzene to
have a reactivity similar to
CH2 CH CH CH CH CH2
250
If resonance were not important for benzene, i.e.
only one of the two preceding resonance
structures were required to describe the structure
of benzene, then we might expect benzene to
have a reactivity similar to
CH2 CH CH CH CH CH2
1,3,5-hexatriene
251
If resonance were not important for benzene, i.e.
only one of the two preceding resonance
structures were required to describe the structure
of benzene, then we might expect benzene to
have a reactivity similar to
CH2 CH CH CH CH CH2
1,3,5-hexatriene
This is not the case!
252
If resonance were not important for benzene, i.e.
only one of the two preceding resonance
structures were required to describe the structure
of benzene, then we might expect benzene to
have a reactivity similar to
CH2 CH CH CH CH CH2
1,3,5-hexatriene
This is not the case! 1,3,5-hexatriene is fairly
reactive with a variety of reagents (e.g. HBr, Cl2,
etc. in the dark). These reagents react only slowly
with benzene.
253
Benzene is more stable than might be
expected by examination of the individual
resonance structures.
254
Naming benzene compounds
Cl
C
H
H
C
C
C
C
C
H
H
H
255
Naming benzene compounds
Cl
C
H
H
C
C
C
C
C
H
H
chlorobenzene
H
256
Br
C
H
H
Br
C
C
C
C
C
H
H
1,2-dibromobenzene
257
Br
Br
C
H
H
Br
C
H
C
C
C
C
C
C
C
C
C
H
H
1,2-dibromobenzene
H
C
H
Br
H
1,3-dibromobenzene
258
Br
Br
C
H
H
C
H
Br
C
C
C
C
C
C
C
C
C
H
H
H
1,2-dibromobenzene
C
H
Br
H
1,3-dibromobenzene
Br
C
H
1,4-dibromobenzene
H
C
C
C
C
C
Br
H
H
259
Br
Br
C
H
H
C
H
Br
C
C
C
C
C
C
C
C
C
H
H
H
o-dibromobenzene
C
H
Br
H
m-dibromobenzene
Br
C
H
p-dibromobenzene
H
C
C
C
C
C
Br
H
H
260
Br
Br
C
H
H
C
H
Br
C
C
C
C
C
C
C
C
C
H
H
H
o-dibromobenzene
o = ortho
m = meta
p = para
C
H
Br
H
m-dibromobenzene
p-dibromobenzene
Br
C
H
H
C
C
C
C
C
Br
H
H
261
Steroids
262
263
264
IUPAC name
(10R, 13R)-10,13-dimethyl-17-(6-methylheptan-2yl)-2,3,4,7,8,9,11,12,14,15,16,17-dodecahydro-1Hcyclopenta[a]phenanthren-3-ol
265
266
267
268
oral contraceptive
269
270
271
Theobromine (replace the CH3 at the arrow by
H) is the stimulant found in
272
Theobromine (replace the CH3 at the arrow by
H) is the stimulant found in chocolate.
273
274
275
276
Stereochemistry
277
Stereochemistry
Stereochemistry: Deals with the 3dimensional arrangement of atoms in space
for a particular chemical structure.
278
Stereochemistry
Stereochemistry: Deals with the 3dimensional arrangement of atoms in space
for a particular chemical structure. It also
deals with how molecules react in 3dimensions.
279
Isomers
280
Isomers
Two or more compounds with the same
molecular formulas but different arrangements
of the atoms in space.
281
Isomers
Two or more compounds with the same
molecular formulas but different arrangements
of the atoms in space.
Three different types of isomerism will be
considered.
282
Isomers
Two or more compounds with the same
molecular formulas but different arrangements
of the atoms in space.
Three different types of isomerism will be
considered.
1. Structural isomers (constitutional isomers)
283
Isomers
Two or more compounds with the same
molecular formulas but different arrangements
of the atoms in space.
Three different types of isomerism will be
considered.
1. Structural isomers (constitutional isomers)
2. Geometric isomers
284
Isomers
Two or more compounds with the same
molecular formulas but different arrangements
of the atoms in space.
Three different types of isomerism will be
considered.
1. Structural isomers (constitutional isomers)
2. Geometric isomers
3. Optical isomers
285
Structural isomers
286
Structural isomers
Structural isomers (constitutional isomers):
Compounds with the same molecular
formulas but different arrangements of the
atoms.
287
Structural isomers
Structural isomers (constitutional isomers):
Compounds with the same molecular
formulas but different arrangements of the
atoms.
Example: Draw the structural isomers for C4H10
288
CH3CH2CH2CH3 butane
289
CH3CH2CH2CH3 butane
CH3CHCH3
CH3
2-methylpropane
(the 2 is redundant in
this name)
290
Example: Draw the structural isomers for C5H12
291
Example: Draw the structural isomers for C5H12
CH3CH2CH2CH2CH3 pentane
292
Example: Draw the structural isomers for C5H12
CH3CH2CH2CH2CH3 pentane
CH3CH2CHCH3
CH3
2-methylbutane
(2 is redundant)
293
Example: Draw the structural isomers for C5H12
CH3CH2CH2CH2CH3 pentane
CH3CH2CHCH3
2-methylbutane
CH3
(2 is redundant)
CH3
CH3CCH3
2,2-dimethylpropane
CH3
(each 2 is redundant)
294
295
296
Example: Draw the structural isomers for C2H6O
297
Example: Draw the structural isomers for C2H6O
CH3CH2OH ethanol
298
Example: Draw the structural isomers for C2H6O
CH3CH2OH ethanol
CH3OCH3
methoxymethane (dimethyl ether)
299
Exercise: Draw and name all the structural
isomers for C6H14 (Answer there are 5).
300
Exercise: Draw and name all the structural
isomers for C6H14 (Answer there are 5).
The number of structural isomers increases
significantly as the number of carbon atoms
increases. For example, C20H42 has 366,319
isomers.
301
Number of carbons
1
2
3
4
5
6
7
8
9
10
20
30
40
Number of isomers
for alkanes
1
1
1
2
3
5
9
18
35
75
366,319
4,111,846,763
62,491,178,805,831
302
Stereoisomerism
303
Stereoisomerism
Stereoisomerism: Isomers having the same
molecular formula and the same atom-toatom bonding, but the atoms differ in their
arrangement in space.
304
Stereoisomerism
Stereoisomerism: Isomers having the same
molecular formula and the same atom-toatom bonding, but the atoms differ in their
arrangement in space.
Geometric isomers: Isomers having the same
atom-to-atom bonding, but the atoms differ
in their arrangement in space.
305
Examples: The trans and cis isomers of
1,2-dichloroethene.
306
Examples: The trans and cis isomers of
1,2-dichloroethene.
H
Cl
C
H
C
trans- 1,2-dichloroethene.
Cl
307
Examples: The trans and cis isomers of
1,2-dichloroethene.
H
Cl
C
C
H
Cl
Cl
Cl
C
H
C
trans- 1,2-dichloroethene.
cis- 1,2-dichloroethene.
H
308
Examples: The trans and cis isomers of
1,2-dichloroethene.
H
Cl
C
C
H
Cl
Cl
Cl
C
H
C
H
trans- 1,2-dichloroethene.
(b.p. 48 oC , m.p. -50 oC)
cis- 1,2-dichloroethene.
(b.p. 60 oC , m.p. -80 oC)
309
An example from inorganic chemistry.
NH3 Cl
Pt
NH3 Cl
cis isomer
NH3
Cl
Pt
Cl
NH3
trans isomer
310
An example from inorganic chemistry.
NH3 Cl
Pt
NH3 Cl
cis isomer
common name: cisplatin
NH3
Cl
Pt
Cl
NH3
trans isomer
311
An example from inorganic chemistry.
NH3 Cl
NH3 Cl
Pt
Pt
NH3 Cl
Cl
NH3
cis isomer
trans isomer
common name: cisplatin
Only the cis isomer is an effective chemotherapy
agent.
312
Optical Isomers - Chirality
313
Optical Isomers - Chirality
Polarized Light: Plane polarized light consists
of electromagnetic waves with the electric
component vibrating in one direction.
314
315
Optical Isomer: An isomer that causes rotation
of the plane of polarization of light when passed
through the substance.
316
317
Chiral (sounds like ki ral): An object that cannot
be superimposed on its mirror image is called
chiral.
318
319
Cl
H
H
C
C
Cl
Cl Cl
Cl
Cl
320
Cl
H
H
C
C
Cl
Cl Cl
Cl
Cl
mirror plane
321
Cl
H
H
C
C
Cl
Cl Cl
Cl
Cl
mirror plane
Can superimpose these two molecules;
trichloromethane is achiral.
322
F
H
H
C
C
Br
Cl Cl
Br
F
mirror plane
323
F
H
H
C
C
Br
Cl Cl
Br
F
mirror plane
Cannot superimpose these two molecules;
bromochlorofluoromethane is chiral.
324
Enantiomers: A chiral molecule and its nonsuperimposable mirror image are called
enantiomers.
325
Enantiomers: A chiral molecule and its nonsuperimposable mirror image are called
enantiomers.
The simplest case is a tetrahedral carbon
bonded to four different groups.
326
Enantiomers: A chiral molecule and its nonsuperimposable mirror image are called
enantiomers.
The simplest case is a tetrahedral carbon
bonded to four different groups.
Chiral molecules lack molecular symmetry.
327
328
HOOC
H
H
C
C
OH HO
CH 3
COOH
CH 3
Lactic acid has optical isomers.
329
One optical isomer is sometimes represented
by a D (for dextrorotatory: Latin dexter, right)
if the rotation of the plane of polarization is to
the right; or L (for levorotatory: Latin laevus,
left), if the rotation of the plane of
polarization is to the left.
330
One optical isomer is sometimes represented
by a D (for dextrorotatory: Latin dexter, right)
if the rotation of the plane of polarization is to
the right; or L (for levorotatory: Latin laevus,
left), if the rotation of the plane of
polarization is to the left. The symbols + for
rotation to the right and - rotation to the left,
are also fairly commonly used.
331
One optical isomer is sometimes represented
by a D (for dextrorotatory: Latin dexter, right)
if the rotation of the plane of polarization is to
the right; or L (for levorotatory: Latin laevus,
left), if the rotation of the plane of
polarization is to the left. The symbols + for
rotation to the right and - rotation to the left,
are also fairly commonly used.
The lactic acid from muscle tissue is
D-lactic acid or (+)-lactic acid.
332
A 50:50 mixture of the + and – isomers of the
same compound is called a racemic mixture.
There is no rotation of the plane of
polarization for a racemic mixture.
333
Polymers
334
Polymer: (Greek: poly meros
many parts)
335
Polymer: (Greek: poly meros
many parts)
Very large molecules with molar masses
ranging from thousands to millions.
336
Polymer: (Greek: poly meros
many parts)
Very large molecules with molar masses
ranging from thousands to millions.
Applications: clothes, food packaging,
appliances with plastic components, etc., etc.,
….
Plastics are polymers.
337
Two basic types of polymer:
338
Two basic types of polymer:
1. Thermoplastics: When heated these soften
and flow, when cooled, they harden again.
This process can be repeated.
339
Two basic types of polymer:
1. Thermoplastics: When heated these soften
and flow, when cooled, they harden again.
This process can be repeated.
Examples: polyethylene and polystyrene
340
Two basic types of polymer:
1. Thermoplastics: When heated these soften
and flow, when cooled, they harden again.
This process can be repeated.
Examples: polyethylene and polystyrene
2. Thermosetting plastics: When first heated
they are plastic, but further heating forms a
highly cross-linked structure. Cannot be
softened by reheating.
341
Two basic types of polymer:
1. Thermoplastics: When heated these soften
and flow, when cooled, they harden again.
This process can be repeated.
Examples: polyethylene and polystyrene
2. Thermosetting plastics: When first heated
they are plastic, but further heating forms a
highly cross-linked structure. Cannot be
softened by reheating. Example: formica.
342
Monomers: The small (low molar mass)
molecules used to synthesize polymers.
343
Synthetic Polymers
344
Synthetic Polymers
Two principal reaction types: Addition and
condensation.
345
Synthetic Polymers
Two principal reaction types: Addition and
condensation.
Addition Polymers: Made by monomer units
directly joining together.
346
Synthetic Polymers
Two principal reaction types: Addition and
condensation.
Addition Polymers: Made by monomer units
directly joining together.
Condensation Polymers: Made by monomer
units combining so that a small molecule,
usually water, is split out.
347
Addition Polymers
348
Addition Polymers
The monomer for addition polymers normally
contains one or more double bonds.
349
Addition Polymers
The monomer for addition polymers normally
contains one or more double bonds.
The polymerization reaction is initiated using
an organic peroxide.
350
Addition Polymers
The monomer for addition polymers normally
contains one or more double bonds.
The polymerization reaction is initiated using
an organic peroxide.
R O O R
R O . + .O R
351
Addition Polymers
The monomer for addition polymers normally
contains one or more double bonds.
The polymerization reaction is initiated using
an organic peroxide.
R O O R
R O . + .O R
organic peroxide free radicals
352
Initiation step:
H
H
C
H
C
H
+ .OR
H
.C
H
H
C OR
H
353
Initiation step:
H
H
C
H
C
H
+ .OR
H
.C
H
H
C OR
H
354
Then
H
C
H
H
H
H
H
C
.C
H
C OR
H
H
H
.C
H
C
H
OR
C
H
H
355
Etcetera:
H
(H
H
C
C
)
H
n
where n would typically range from 1000 to
50,000.
356
Different experimental conditions give different
polymers.
H
_
_
CH 2 CH 2
_
C
_
CH 2
_
RCH 2CH 2  H
357
Different experimental conditions give different
polymers.
H
_
_
CH 2 CH 2
_
C
_
CH 2
_
RCH 2CH 2  H
358
Different experimental conditions give different
polymers.
H
_
_
CH 2 CH 2
_
C
RCH 2CH 2  H
_
CH 2
_
_
_
_
CH 2 CH 2 CH
_
CH 2
_
CH 2
CH 2
+ H
R
359
Different experimental conditions give different
polymers.
H
_
_
CH 2 CH 2
_
C
RCH 2CH 2  H
_
CH 2
_
_
_
_
CH 2 CH 2 CH
_
CH 2
_
CH 2
CH 2
+ H
R
branched polymer chain
360
Cross linked polymers are formed in the
following manner:
_
_
_
CH 2 CH 2 CH
H
_
CH 2
_
R
RO 
361
Cross linked polymers are formed in the
following manner:
_
_
_
CH 2 CH 2 CH
H
_
CH 2
_
R
RO 
_
_
_
CH 2 CH 2 C H

_
CH 2
_
362
Cross linked polymers are formed in the
following manner:
_
_
_
CH 2 CH 2 CH
H
_
CH 2
_
R
RO 
_
_
_
CH 2 CH 2 C H

H
H
_
CH 2
_
H
C
C
H
363
Cross linked polymers are formed in the
following manner:
_
_
_
CH 2 CH 2 CH
H
_
CH 2
_
R
RO 
_
_
_
CH 2 CH 2 C H

H
H
_
CH 2
_
H
C
C
H
364
Cross linked polymers are formed in the
following manner:
_
_
_
CH 2 CH 2 CH
H
_
CH 2
_
R
_
RO 
_
_
CH 2 CH 2 C H

H
_
CH 2
_
H
C
C
H
H
_
_
_
CH 2 CH 2 CH
_
CH 2
_
CH 2
C H2

365
_
_
_
CH 2 CH 2 CH
_
CH 2
_
CH 2
C H2

_
_
CH 2
 _
_
CH 2 C H CH _
2
366
_
_
_
CH 2 CH 2 CH
_
CH 2
_
CH 2
C H2

_
_
CH 2
 _
_
CH 2 C H CH _
2
_
_
_
CH 2 CH 2 CH
_
CH 2
_
CH 2
_
_
_
CH 2
CH 2 CH 2 CH
_
CH 2
_
367
_
_
_
CH 2 CH 2 CH
_
CH 2
_
CH 2
C H2

_
_
CH 2
 _
_
CH 2 C H CH _
2
_
_
_
CH 2 CH 2 CH
_
CH 2
_
CH 2
cross linked polymer
_
_
_
CH 2
CH 2 CH 2 CH
_
CH 2
_
368
Polyethylene is the most widely used polymer.
369
Polyethylene is the most widely used polymer.
The long linear chain version is called high
density polyethylene (HDPE) (d = 0.97 g/ml).
370
Polyethylene is the most widely used polymer.
The long linear chain version is called high
density polyethylene (HDPE) (d = 0.97 g/ml).
It is hard, tough, and rigid. Used for milk and
detergent containers.
371
The branched chain version is called low
density polyethylene (LDPE) (d=0.92 g/ml).
The branched chains of polyethylene prevent
close packing – hence the density is lower.
372
The branched chain version is called low
density polyethylene (LDPE) (d=0.92 g/ml).
The branched chains of polyethylene prevent
close packing – hence the density is lower.
This polymer is soft and flexible. Used for
grocery bags, bread bags, etc.
373
The cross linked polymer is called cross-linked
polyethylene (CLPE). This is a very tough
material. Used for plastic caps on soft drink
bottles.
374
375
Condensation Polymers
376
Condensation Polymers
A condensation reaction occurs when two
molecules react by splitting out or eliminating
a small molecule such as water.
377
Ester formation reaction:
CH3CO2H + CH3CH2OH
acetic acid
ethanol
CH3CO2CH2CH3 + H2O
ethyl acetate
Polyesters
O
O
C
C
2
H O terephthalic acid O
O
H O
H
+2 H _ O _ CH 2 _ CH 2 _ O _ H
ethylene glycol
O
C
C
_
_
_
_
O CH 2 CH 2 O
O
_C
+2 H2O
O
C
O
CH 2
CH 2
O
H
379
Polyesters
O
O
C
C
2
H O terephthalic acid O
O
ethylene glycol
O
C
H O
H
+2 H _ O _ CH 2 _ CH 2 _ O _ H
C
_
_
_
_
O CH 2 CH 2 O
O
_C
+2 H2O
O
C
O
CH 2
CH 2
O
Now consider another terephthalic acid molecule
reacting with the indicated alcohol functional group.
H
380
O
O
C
O
C
_
_
_
_
O CH 2 CH 2 O
_
n
This is an example of the repeat unit for a polyester. In
this case it is poly(ethylene terephthalate) called PET.
381