Hydrocarbon
.Alkanes
Preparation
from alkenes via
Hydrogenation
>
-
Exothermic
c + c /Pt/Pd< c -
C
>
-
Pt and Pd work at room temperature but Ni
needs and
Ni
high temperature high pressure
from alkyl halides Reduction H
+
via
=
+
->
All alkyl halides except florine R -
x R -
H
>
- Also can be done with In + did HC
from alkyl halides via Wurtz Reaction Na
for preparation of higer alkanes
2R-XTyether s R R NaX
+
>
-
Used -
2
with even number of carbon atoms
Lime
Decarbonitation
-Toda
from carbonilic acid via
>
-
The number of Carbon decreases
by 1 R-Cook
Soda lime =
NaOH + CaO
Kolbe's
from carbonilic acid
of
via
sodium
electrolyticof method
carbonilic acid
An sollution potassium salt
electrolysis gives alkane
>
-
aqueous or a on
cointaing
of
Electrolysis
even number carbon atoms at anode
>
-
Combination of free radicle takes place R-cooNa--R- R
Chemical Properties H
I
H
I
Substitution R -
c
I
-
HR -
C
I
-
X
Lower do and
alkanes not
undergo nitration sulphonation .
H H
Halogenation
Takes place at
higher temperature or in the presence of diffused sunlight ultra or voiled
light
- ree radical chain mechanism
involving initiation , propagation and termination
Rate :
F2 >
Cl > Br >
I2 Florination is too violent and Iodination is slow
very
:
3 > zo >
Controlled Oxidation
pyQ
Fertitary Hatom be alcohols
>
-
Ordinary alkanes resist onidation but alkanes having can ouidized to
corresponding
Moz 03
(CH3) CHMOs (CH3) 3 COL CHu
OcHCHO TO
+
Oxidation
CH3 [00] Mn Cu1523k
2CzHs +
002 >
-
.
2 CHCOOH 2CHu + 0 - > 2 CH3OH
-
- atm 100
lacid) CAlcohol)
, #
Isomerisation
n-Alkanes to
branching
Anhy AlCIs + HC
Aromatization (Reforming)
>
-
Presence
or chromium
dehydrogenated
of onides
supported
and
of vandium
cyclised
over
,
to
molybdeum
alumina
benzen
get - 10 -
20 atm
Note :
Pyrolysis Cracking free radide mechanism >
-
Liquid Hydrocarbon could be converted in
hydrocarbons
or >
-
gaseous
Reaction of Alkanes with steam is used for industrial preparation of steam
Combustion
Cutty + (x + 0 > xCO2
-
+
240
Cass Notes
Wurtz Reaction
>
-
Useful for preparation of symmetrical alkanes
having even number of carbon atoms Rate of Reaction
If form RI RBU RCK RE
Na
two
halogens are
present then a
sing
> >
R -X - R -
R : -
X
Na i 23
:
eg
Dry ether
X-
-
DE
Frankland Reaction
2m
R-X- > R- R
Kolbe's
Electrolysis R-CooNaErectrolysis > R-R
Reaction
Coreyof House
&
unsymmetrical
>
-
alkanes
synthesis
LiR= Ca-Gilmann
reagent is formed as an
intermediate
Rate determining step is the attack of R
Rate : RI > RBu > RC1 > Rf
De carbonitation Reaction
H
RCOOH
>
-
Soda Lime =
NaOH + Ca0 >
- used or
R-H
The Carbon chain decreases
by 1 Carbon
RCooNa
>
-
Rate formation of Carbanion
determining
>
-
>
-
>
-
Sometimes Lead Tetra acetque PbCoAc) a
and Chlorofom (CHCb)
are used for good yeild of Alkane.
Diamide Reduction Reaction
c
=
-
.Alkanes
Preparation
from alkenes via
Hydrogenation
>
-
Exothermic
c + c /Pt/Pd< c -
C
>
-
Pt and Pd work at room temperature but Ni
needs and
Ni
high temperature high pressure
from alkyl halides Reduction H
+
via
=
+
->
All alkyl halides except florine R -
x R -
H
>
- Also can be done with In + did HC
from alkyl halides via Wurtz Reaction Na
for preparation of higer alkanes
2R-XTyether s R R NaX
+
>
-
Used -
2
with even number of carbon atoms
Lime
Decarbonitation
-Toda
from carbonilic acid via
>
-
The number of Carbon decreases
by 1 R-Cook
Soda lime =
NaOH + CaO
Kolbe's
from carbonilic acid
of
via
sodium
electrolyticof method
carbonilic acid
An sollution potassium salt
electrolysis gives alkane
>
-
aqueous or a on
cointaing
of
Electrolysis
even number carbon atoms at anode
>
-
Combination of free radicle takes place R-cooNa--R- R
Chemical Properties H
I
H
I
Substitution R -
c
I
-
HR -
C
I
-
X
Lower do and
alkanes not
undergo nitration sulphonation .
H H
Halogenation
Takes place at
higher temperature or in the presence of diffused sunlight ultra or voiled
light
- ree radical chain mechanism
involving initiation , propagation and termination
Rate :
F2 >
Cl > Br >
I2 Florination is too violent and Iodination is slow
very
:
3 > zo >
Controlled Oxidation
pyQ
Fertitary Hatom be alcohols
>
-
Ordinary alkanes resist onidation but alkanes having can ouidized to
corresponding
Moz 03
(CH3) CHMOs (CH3) 3 COL CHu
OcHCHO TO
+
Oxidation
CH3 [00] Mn Cu1523k
2CzHs +
002 >
-
.
2 CHCOOH 2CHu + 0 - > 2 CH3OH
-
- atm 100
lacid) CAlcohol)
, #
Isomerisation
n-Alkanes to
branching
Anhy AlCIs + HC
Aromatization (Reforming)
>
-
Presence
or chromium
dehydrogenated
of onides
supported
and
of vandium
cyclised
over
,
to
molybdeum
alumina
benzen
get - 10 -
20 atm
Note :
Pyrolysis Cracking free radide mechanism >
-
Liquid Hydrocarbon could be converted in
hydrocarbons
or >
-
gaseous
Reaction of Alkanes with steam is used for industrial preparation of steam
Combustion
Cutty + (x + 0 > xCO2
-
+
240
Cass Notes
Wurtz Reaction
>
-
Useful for preparation of symmetrical alkanes
having even number of carbon atoms Rate of Reaction
If form RI RBU RCK RE
Na
two
halogens are
present then a
sing
> >
R -X - R -
R : -
X
Na i 23
:
eg
Dry ether
X-
-
DE
Frankland Reaction
2m
R-X- > R- R
Kolbe's
Electrolysis R-CooNaErectrolysis > R-R
Reaction
Coreyof House
&
unsymmetrical
>
-
alkanes
synthesis
LiR= Ca-Gilmann
reagent is formed as an
intermediate
Rate determining step is the attack of R
Rate : RI > RBu > RC1 > Rf
De carbonitation Reaction
H
RCOOH
>
-
Soda Lime =
NaOH + Ca0 >
- used or
R-H
The Carbon chain decreases
by 1 Carbon
RCooNa
>
-
Rate formation of Carbanion
determining
>
-
>
-
>
-
Sometimes Lead Tetra acetque PbCoAc) a
and Chlorofom (CHCb)
are used for good yeild of Alkane.
Diamide Reduction Reaction
c
=
-
