Transcript Benzene and Substitution Reactions

Benzene
and
Electrophilic Aromatic
Substitution
1
1
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Aromatic Hydrocarbons (Arenes)
• Simplest member : Benzene, C6H6
• Characteristic aroma
• Alkylbenzene, Cn+6H2n+6
E.g.
CH3
C6H5CH3
2
2
C6H5C2H5
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Aromatic Hydrocarbons (Arenes)
• Generally less dense than water
• Insoluble in water but soluble in many
organic solvents
3
3
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Aromatic Hydrocarbons (Arenes)
• PAHs : Polycyclic aromatic hydrocarbons
• Fused aromatic rings
4
4
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Aromatic Hydrocarbons (Arenes)
• No heteroatoms
N
B
5
5
Not PAH
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Aromatic Hydrocarbons (Arenes)
• PAHs : Polycyclic aromatic hydrocarbons
Sources : - incomplete combustion of
wood, coal, diesel, fat, or tobacco
Q.38
6
6
benzocyclobutadiene
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
PAHs : Polyaromatic hydrocarbons
Toxic and carcinogenic
Benzo(a)pyrene : - first carcinogen discovered
Found in : - tobacco smoke,
- char-grilled food
- burnt toast,
- edible oils
7
7
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Preparation of
Benzene
8
8
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
1. Destructive Distillation of Coal
9
9
•
Gives coal gas, ammoniacal liquor,
coal tar and coke as products
•
The coal tar produced is a mixture
of many organic compounds (mainly
aromatic ones)
•
benzene and methylbenzene can be
obtained by fractional distillation
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
1. Destructive Distillation of Coal
10
10
A laboratory
set-up of the
destructive
distillation of
coal
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Industrial Preparation
2. Catalytic trimerization of ethyne
organonickel cat alyst
3 HC
11
11
CH
70oC, under pressure
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Industrial Preparation
3. Catalytic Reforming of Petroleum
•
Converts alkanes and cycloalkanes
into aromatic hydrocarbons
Pt
C6H14  C6H6 + 4H2
500 oC, 10 – 20 atm
12
12
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Laboratory Synthesis
1. Decarboxylation of Sodium Salt of Benzoic Acid
•
When sodium benzoate is fused with
sodium hydroxide
 the carboxylate group is removed
13
13
volatile
Benzene is separated by fractional distillation
New Way Chemistry for Hong Kong A-Level Book 3A
2. Reduction of Phenol
•
Passing phenol vapour over heated zinc
dust (reducing agent)
 produce benzene and zinc(II) oxide
volatile
14
14
Benzene is separated by fractional distillation
New Way Chemistry for Hong Kong A-Level Book 3A
Reactions of
Benzene
15
15
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Reactivity of Benzene
Unreactive towards addition reactions due to
stabilization of the system by delocalization
of -electrons
16
16
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Reactivity of Benzene
Not oxidized by KMnO4
17
17
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Reactivity of Benzene
Br2 / HBr / H2O
Resistant to electrophilic
addition
18
18
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Reactivity of Benzene
Resistant to catalytic
hydrogenation
19
19
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Addition reactions occur only under drastic
conditions.
excess H2, high T &P
Ni or P t or P d
20
20
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Occur only
under drastic
conditions
No
reaction
21
21
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
The -electron cloud is susceptible to
electrophilic attack.
Substitution is preferred to addition since
the former retains aromaticity.
Electrophilic aromatic substitution (SE)
22
22
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
23
23
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Electrophilic Aromatic Substitution
Reactions
E+ : electrophile
24
24
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
General Reaction Mechanism
Step 1:
•
25
25
Rate determining step
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
General Reaction Mechanism
•
Stabilized by delocalization of 
electrons
+
26
26
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
General Reaction Mechanism
Step 2:
•
The carbocation loses a hydrogen ion
 forms the substitution product
27
27
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
1. Halogenation
No
apparent
reation
Catalysts : AlCl3, FeCl3 or FeBr3
28
28
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
1. Halogenation - Mechanism
Step 1:
•
The catalyst (FeBr3) combines with
bromine to give a complex
Br
29
29
Br
FeBr3
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Br [FeBr4]
Step 2:
•
Formation of carbocation intermediate
•
Rate determining step
+
30
30
Br [FeBr]
Br
Br
Br
H
H
H
Stabilized by delocalization of -electrons
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Step 3:
•
The catalyst (FeBr3) is regenerated
Fumes of HBr(g) are produced, indicating
substitution rather than addition has occurred.
31
31
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
2. Nitration
32
32
•
Benzene reacts readily with a mixture
of conc. HNO3 and conc. H2SO4
•
Conc. H2SO4 increases the rate of
reaction by increasing the concentration
of the electrophile, NO2+
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
O
H2SO 4
acid
+
HO
H
N
base
O
O
O
N
H
O
N
O
O
+
H2O
electrophile
2HNO3
33
33
NO3 + H2O + NO2+
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
NO2
NO2
conc. HNO3
conc. H2SO 4, 95oC
NO2
NO2
NO2
conc. HNO3
conc. H2SO 4, 110oC
NO2
Optional
34
34
O2N
NO2
meta-directing
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Q.39
H2SO4 + HNO3
NO2+ + H2O + HSO4
O
O
35
35
N
O
O
N
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
O
O
N
36
O
O
N
New Way Chemistry for Hong Kong A-Level Book 3A
O
O
N
O
O
HSO4
NO2
N
H
+ H2SO4
37
New Way Chemistry for Hong Kong A-Level Book 3A
3. Sulphonation
•
(H2SO4 + SO3)
Benzene reacts with fuming sulphuric
acid at room temp
 form benzenesulphonic acid
+
38
38
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
3. Sulphonation
•
Sulphonation is a reversible process
•
By heating an aqueous solution of
benzenesulphonic acid to above 100 oC
 benzene and sulphuric acid are formed
heat
39
39
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Q.40
H2SO4 + H2SO4
SO3 + H3O+ + HSO4
O
O
O
S
O
40
40
O
S
O
H
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
O
O
41
S
O
O
O
H
O
S
O
H
O
New Way Chemistry for Hong Kong A-Level Book 3A
S
O
H
HSO4
O
O
S
O
H
SO3H
SO3
H+
+ H2SO4
42
New Way Chemistry for Hong Kong A-Level Book 3A
4. Friedel-Crafts Alkylation
•
When benzene is warmed with a
haloalkane in the presence of AlCl3 as a
catalyst
 alkylbenzene is formed
43
43
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
4. Friedel-Crafts Alkylation
Important starting step in the manufacture
of styrene, phenol and detergents
The alkyl group introduced activates the ring
towards further alkylation by +ve I-effect.
 Friedel-Crafts alkylation is not a good way
to prepare alkylbenzene.
44
44
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
deactivating
R
R
O
CH2
C
O
C
+
Cl
Hg/Zn
R
AlCl3
Friedel-Craft
acylation
45
45
conc. HCl
Clemensen
reduction
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Devise a reaction pathway of not more than
four steps for the following conversion.
CH3
COOH
6B 09/07/2011
46
46
New Way Chemistry for Hong Kong A-Level Book 3A
47
47
New Way Chemistry for Hong Kong A-Level Book 3A
Chlorination
Bromination or Friedel-Craft reaction
Soda lime to absorb
HBr or HCl fumes
Br2, RCl or RCOCl
or AlCl3
48
48
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Q.41
electrophile
CH3Cl + AlCl3  [CH3]+[AlCl4]
49
49
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
AlCl4
H
CH3
H
C
H
H
t wo more structures
CH3
+ HCl + AlCl3
50
New Way Chemistry for Hong Kong A-Level Book 3A
Q.42(a)
2C6H6 + X
AlCl3
C6H5CH2C6H5 + 2HCl
X : CH2Cl2
51
51
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
CH2Cl
CH2Cl2
CH2
AlCl3
AlCl3
(excess)
-CH2Cl deactivate the ring
Susceptibility to SE reaction :
52
52
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
CH2Cl
>
Q.42(b)
3C6H6 + Y
AlCl3
(C6H5)3CH + 3HCl
Y : CHCl3
53
53
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
CHCl2
CHCl3
CHCl
AlCl3
AlCl3
(excess)
AlCl3
C
54
54
H
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Q.42(c)
2C6H6 + Z
AlCl3
C6H5CH2CH2C6H5 + 2HCl
Z : CH2ClCH2Cl
55
55
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
ClH2C
ClH2C
CH2Cl
AlCl3
AlCl3
(excess)
56
56
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Industrial preparation of toluene
CH3
1.
Fract ional
Coal t ar
dist illat ion
CH3
2.
57
57
P et roleum
Fract ional
dist illat ion
CH3
catalyst
high T & P
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
+
3H2
Laboratory Preparation of Methylbenzene
1. Friedel-Crafts acylation of benzene
followed by Clemensen reduction.
2.Friedel-Crafts alkylation of benzene is not
recommended as further alkylation will
take place giving a mixture of
alkylbenzenes that are difficult to be
separated.
58
58
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Reactions of methylbenzene and Other
Alkylbenzenes
1. Electrophilic aromatic substitution rxs
more susceptible to electrophilic attacks
∵ alkyl groups activate the ring by positive
inductive effect.
59
59
New Way Chemistry for Hong Kong A-Level Book 3A
2. Reactions of the side chain
(a)
Free radical substitution vs
electrophilic substitution at the ring
Free radical
substitution
Electrophilic
substitution
60
60
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Benzylic hydrogens are much more susceptible
to free radical substitution than hydrogens at
other positions.
Major
products
61
61
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
(b)
Oxidation at the benzylic carbon
Absence of
benzylic H
62
62
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
If alkaline KMnO4 is used, the resulting
mixture must be acidified in order to obtain
the benzoic acid.
COO-
CH3
KMnO 4 / OH-
COOH
H+
heat
Or,
CH3
COOH
1. KMnO 4 / OH-, heat
2. H+
63
63
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Structural determination of isomeric alkylbenzene
H3C
CH3
CH3
CH2CH3
alkylbenzenes
with very close
boiling points
CH3
b.p. 144oC
b.p. 139oC
CH3
b.p. 138oC
b.p. 136oC
CH3
COOH
COOH
C8H10
COOH
COOH
acids with
different
melting points
COOH
COOH
o
m.p. 231C
o
m.p. 348C
m.p. 300oC
m.p. 122oC
COOH
64
64
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Structural determination of isomeric alkylbenzene
H3C
CH3
CH3
CH2CH3
alkylbenzenes
with very close
boiling points
CH3
b.p. 144oC
b.p. 139oC
CH3
b.p. 138oC
b.p. 136oC
CH3
COOH
COOH
COOH
COOH
COOH
COOH
o
m.p. 231C
o
m.p. 348C
acids with
different
melting points
m.p. 300oC
m.p. 122oC
COOH
65
65
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Q.43(a)
O
COOH
1. MnO4- / OH+
2. H+
66
66
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
C
HO
CH3
Q.43(b)
Terminal alkene gives CO2
COOH
1. MnO4- / OH+
2. H+
COOH
COOH
1. MnO4- / OH2. H+
COOH
COOH
1. MnO4- / OH2. H+
67
67
HOOC
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
+ H2O
CO2
Q.43(b)
1.
MnO4-
-
/ OH
2. H+
68
68
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
COOH
Q.43(b)
COOH
1. MnO4- / OH2. H+
COOH
1. MnO4- / OH2. H+
69
69
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
COOH
COOH
Q.43(b)
1.
MnO 4-
COOH
-
/ OH
2. H+
1.
MnO4-
-
/ OH
2. H+
70
70
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
COOH
Q.43(c)
1. MnO4- / OH+
2. H
71
71
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
O
+
CO2
+ H2O
The END
72
72
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
29.2 Nomenclature of the Derivatives of Benzene (SB p.191)
Back
Draw the structural formula for each of the following
compounds:
(a) 1,3,5-Trichlorobenzene
(b) 2,5-Dibromophenol
(c) 2,4-Dinitrobenzoic acid
(a)
73
73
(b)
Answer
(c)
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
29.2 Nomenclature of the Derivatives of Benzene (SB p.192)
Give the IUPAC name for each of the following
compounds:
(a)
(b)
74
74
(a) 1,2-Dimethylbenzene
(b) 1-Methyl-2-nitrobenzene or 2nitrotoluene
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Answer
29.2 Nomenclature of the Derivatives of Benzene (SB p.192)
Back
Give the IUPAC name for each of the following
compounds:
(c)
(c) 3-Bromo-5-chlorobenzoic acid
(d) 4-Bromo-2,6-dinitrophenol
(d)
75
75
Answer
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
29.3 Structure of Benzene and Aromaticity (SB p.195)
The basic structural requirement for aromatic
compounds is that the molecule must be planar,
cyclic and with (4n + 2)  electrons delocalized in
the ring. n must be a natural number (i.e. n = 1, 2, 3, and
so on).
There are aromatic compounds without benzene ring.
An example is the 1,3-cyclopentadienyl anion. Can you
draw its structure and explain its aromaticity?
Answer
76
76
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
29.3 Structure of Benzene and Aromaticity (SB p.195)
Back
Cyclopentadienyl anion is an aromatic anion. It has six π
electrons delocalized over a completely conjugated planar
monocyclic system of five sp2 hybridized carbon atoms.
Cyclopentadienyl anion
77
77
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
29.4 Physical Properties of Aromatic Hydrocarbons (SB p.197)
PAHs are formed from partial combustion and pyrolysis
of aromatic compounds. They are in common occurrence
in our environment. List some important uses of
aromatic hydrocarbons and how they release PAHs to
our environment.
Answer
78
78
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
29.4 Physical Properties of Aromatic Hydrocarbons (SB p.197)
Aromatic hydrocarbons are the raw materials for the manufacture of
monomers and plasticizers in polymers, commonly used as solvents
and important constituents of lead-free gasoline.
Incomplete combustion and pyrolysis process favour the production
of PAHs. These compounds are encountered abundantly in the
atmosphere, soil and elsewhere in the environment from sources
that include engine exhaust, wood stove smoke, cigarette smoke
and charbroiled food. Coal tar and petroleum residues such as road
and roofing asphalt have high levels of PAHs.
Back
79
79
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
29.6 Reactions of Benzene (SB p.203)
Back
Complete each of the following by supplying the missing
reactant or product as indicated by the question mark:
(a)
(a)
(b)
(b) conc. H2SO4, conc. HNO3
(c) fuming H2SO4
(c)
Answer
80
80
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
29.6 Reactions of Benzene (SB p.203)
(a) One mole of benzene reacts with three moles of
chlorine under special conditions. What are the
conditions required for the reaction?
Answer
(a) UV radiation or diffuse sunlight must
be present for the free radical addition
reaction to take place.
81
81
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
29.6 Reactions of Benzene (SB p.203)
(b) Draw the structure of the reaction product in (a).
Answer
(b)
82
82
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
29.6 Reactions of Benzene (SB p.203)
(c) Methylbenzene undergoes two different types of
chlorination reaction by different mechanisms.
Compare the two different types of chlorination
reaction in terms of reaction conditions as well as the
products formed.
Answer
83
83
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
29.6 Reactions of Benzene (SB p.203)
Back
(c) The two different types of chlorination reaction of methylbenzene
are:
Type I: free radical substitution reaction
Type II: electrophilic aromatic substitution reaction
84
84
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Comparison of some reactions of cyclohexane,
cyclohexene and methylbenzene
Reaction
Cyclohexane (a
saturated
alicyclic
hydrocarbon)
Cyclohexene (an
unsaturated
alicyclic
hydrocarbon)
Methylbenzene
(an aromatic
hydrocarbon)
Action of
bromine in
1,1,1trichloroethane (in
dark)
No reaction
Bromine is
decolourized and no
hydrogen bromide is
evolved
No reaction with
bromine alone. In
the presence of
iron(III) bromide,
bromine is
decolourized and
hydrogen
bromide fumes
are evolved
85
85
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
Comparison of some reactions of cyclohexane,
cyclohexene and methylbenzene
Reaction Cyclohexane Cyclohexene (an Methylbenzen
(a saturated
unsaturated
e (an aromatic
alicyclic
alicyclic
hydrocarbon)
hydrocarbon)
hydrocarbon)
Action of
hydrogen
(with
nickel
catalyst)
86
86
No reaction
One mole of
cyclohexene
reacts with one
mole of hydrogen
at room
temperature
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
One mole of
methylbenzene
reacts with
three moles of
hydrogen at
high
temperature
Comparison of some reactions of cyclohexane,
cyclohexene and methylbenzene
Reaction Cyclohexane Cyclohexene (an Methylbenzen
(a saturated
unsaturated
e (an aromatic
alicyclic
alicyclic
hydrocarbon)
hydrocarbon)
hydrocarbon)
Action of
acidified
potassium
manganat
e(VII)
87
87
No reaction
Acidified
potassium
manganate(VII)
solution is
decolourized
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A
No reaction
Comparison of some reactions of cyclohexane,
cyclohexene and methylbenzene
Reaction Cyclohexane Cyclohexene (an Methylbenzen
(a saturated
unsaturated
e (an aromatic
alicyclic
alicyclic
hydrocarbon)
hydrocarbon)
hydrocarbon)
Action of
No reaction Cyclohexene is
A yellow liquid
concentrat
oxidized and the
is formed
ed nitric
colour darkens
acid and
concentrat
ed
sulphuric
acid
88
88
New Way Chemistry for Hong Kong A-Level 3A
New Way Chemistry for Hong Kong A-Level Book 3A