Some simple reactions of alkanes,
alkenes, and alkynes
2281
Some simple reactions of alkanes,
alkenes, and alkynes
Combustion:
CH4 + 2 O2
CO2 + 2 H2O
2282
Some simple reactions of alkanes,
alkenes, and alkynes
Combustion:
CH4 + 2 O2
CO2 + 2 H2O
When the products are CO2 and H2O it is termed a
complete combustion.
2283
Some simple reactions of alkanes,
alkenes, and alkynes
Combustion:
CH4 + 2 O2
CO2 + 2 H2O
When the products are CO2 and H2O it is termed a
complete combustion.
With insufficient O2, CO will be formed. E. g.
2 CH4 + 3 O2
2 CO + 4 H2O
2284
Some simple reactions of alkanes,
alkenes, and alkynes
Combustion:
CH4 + 2 O2
CO2 + 2 H2O
When the products are CO2 and H2O it is termed a
complete combustion.
With insufficient O2, CO will be formed. E. g.
2 CH4 + 3 O2
2 CO + 4 H2O
This is called an incomplete combustion.
2285
Alkyne combustion reaction:
2 C2H2 + 5 O2
4 CO2 + 2 H2O
The combustion reactions are all exothermic.
2286
Substitution Reactions
2287
Substitution Reactions
Reaction with chlorine:
2288
Substitution Reactions
Reaction with chlorine:
CH4 + Cl2
CH3Cl + HCl
chloromethane
2289
Substitution Reactions
Reaction with chlorine:
CH4 + Cl2
CH3Cl + HCl
chloromethane
CH3Cl + Cl2
CH2Cl2 + HCl
dichloromethane
2290
CH2Cl2 + Cl2
CHCl3 + HCl
trichloromethane
2291
CH2Cl2 + Cl2
CHCl3 + HCl
trichloromethane
CHCl3 + Cl2
CCl4 + HCl
tetrachloromethane
2292
For organic reactions it is common practice to
indicate the reaction conditions. That is, for
the reaction with chlorine:
2293
For organic reactions it is common practice to
indicate the reaction conditions. That is, for
the reaction with chlorine:
CH4 + Cl2
CH3Cl + HCl
2294
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
2295
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.
2296
Addition Reactions
2297
Cl2 +
H
H
H
C C
H
dark
25 oC
Cl Cl
H C C H
H
H
1,2- dichloroethane
2298
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).
2299
H2SO4
CH2CH2 + H2O
CH3CH2OH
2300
Hydrogenation
The following reaction is an example of
hydrogenation of an alkene, addition of H2
across a double bond.
2301
H
C C
H
H
H
ethene
+ H2
H H
H C C H
H
H
ethane
2302
Functional Group Concept
2303
Functional Group Concept
A great many organic molecules have complex
structures.
2304
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.
2305
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.
2306
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.
2307
When these units are found in complex
structures, predictions can be made as to the
likely properties and reactions of the complex
structure.
2308
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.
2309
Some common functional groups
Functional
group
formula
Name
Example
IUPAC Name
Common Name
2310
Some common functional groups
Functional
group
formula
Name
Example
IUPAC Name
R O
alcohol
CH3OH
methanol
H
Common Name
methyl alcohol
2311
Some common functional groups
Functional
group
formula
Name
Example
IUPAC Name
R O
alcohol
CH3OH
methanol
H
O
R C
carboxylic CH3CO2H
_
acid
O H
ethanoic acid
Common Name
methyl alcohol
acetic acid
2312
Some common functional groups
Functional
group
formula
Name
Example
IUPAC Name
R O
alcohol
CH3OH
methanol
H
O
R C
carboxylic CH3CO2H
_
acid
O H
O
R C R
ketone
CH3COCH3
Common Name
methyl alcohol
ethanoic acid
acetic acid
propanone
acetone
2313
Some common functional groups
Functional
group
formula
Name
Example
IUPAC Name
R O
alcohol
CH3OH
methanol
H
O
R C
carboxylic CH3CO2H
_
acid
O H
O
R C R
ketone
CH3COCH3
Common Name
methyl alcohol
ethanoic acid
acetic acid
propanone
acetone
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).
2314
Functional
group
formula
Name
Example
IUPAC Name
Common Name
O
R
C
H
aldehyde
HCHO
methanal
formaldehyde
2315
Functional
group
formula
Name
Example
IUPAC Name
Common Name
O
R
C
R C
H
aldehyde
O
O R
HCHO
methanal
formaldehyde
ester CH3CO2CH2CH3 ethyl ethanoate ethyl acetate
2316
Functional
group
formula
Name
Example
IUPAC Name
Common Name
O
R
C
R C
R
H
aldehyde
O
O R
NH2
HCHO
methanal
formaldehyde
ester CH3CO2CH2CH3 ethyl ethanoate ethyl acetate
amine
CH3NH2
aminomethane
methylamine
2317
Functional
group
formula
Name
Example
IUPAC Name
Common Name
O
R
C
R C
R
H
aldehyde
O
O R
NH2
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!).
2318
Functional
group
formula
R
O
R
Name
ether
Example
IUPAC Name
CH3OCH3 methoxymethane
Common Name
dimethyl ether
2319
Functional
group
formula
R
R
O
Name
Example
IUPAC Name
ether
CH3OCH3 methoxymethane
amide
CH3CONH2
Common Name
dimethyl ether
O
R C
NH2
ethanamide
2320
Functional
group
formula
R
R
O
Name
Example
IUPAC Name
ether
CH3OCH3 methoxymethane
amide
CH3CONH2
Common Name
dimethyl ether
O
R C
NH2
ethanamide
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).
2321
Summary of name endings
2322
Summary of name endings
Functional group Parent alkane
name ending
2323
Summary of name endings
Functional group Parent alkane
name ending
alcohol
change e
to
ol
2324
Summary of name endings
Functional group Parent alkane
name ending
alcohol
change e
to
ol
carboxylic acid
change e
to
oic acid
2325
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
2326
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
2327
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
2328
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
2329
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
2330
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.
2331
Key comment on a functional group
The carboxylic acid is a combination of two
functions groups:
O
C
O
C
O H
carboxylic acid
carbonyl
plus
O
H
alcohol
2332
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
carbonyl
HOWEVER, a compound such as
O
H
alcohol
2333
CH3CH2CCH2CH2 OH
O
would NOT function like a carboxylic acid, but
as an alcohol in some reactions and a ketone
in some other reactions.
2334
IUPAC nomenclature versus common
North American text book usage.
Some examples:
Compound
North American
CH2=CHCH2CH3
1-butene
CH3CH2CH2OH
1-propanol
CH3CH2CH2COCH3 2-pentanone
IUPAC
but-1-ene
propan-1-ol
pentan-2-one
2335
Amino acids
Amino acids are an extremely important class of
organic compounds that have at least two functional
groups (as the name would suggest). The carboxylic
acid group – CO2H and the amine group – NH2. One of
the simplest of the α−amino acids is alanine:
H
H2N– C– CO2H
CH3
2336
In solution the following change takes place:
H
H
+
H2N– C– CO2H
H3N– C– CO-2
CH3
CH3
This is called a zwitterion.
2337
The common α−amino acids have the following
structures, where R represents a hydrogen, alkyl or
more complicated group.
H
H2N– C– CO2H
R
The α−amino acids are important because they are
the building blocks of proteins.
2338
The 20 most
common amino
acids. The forms
shown correspond
to physiological
pH.
2339
Comparison of some properties
2340