Preparation: Ammonolysis of Alkyl Halides (Part -10) - Organic Compounds containing Nitrogen Video Lecture - Class 12

hello friends this video is part 10 is
brought to you by exam viacom no more
fear from exam the next is a Mundell
Isis of al-qaeda highlight this is
another new method to prepare so it is
of alkyl halide so alkyl halides will
form rx-8 that is my alkyl halide so we
have discussed this in one full chapter
al qaeda writes you take any al-qaeda
white also called haloalkanes also
called hurricanes you treat this with
actress or alcoholic ammonia and it's
three what you get is a means see I have
my mean right then react this guy with
rx this Alex so what will happen is one
of the hydrogen's will be the place with
our and HCl will come out so what you
get is NH two are correct so I have this
in is three I'm reacting with our X so
what will happen is this will come out
and this nitrogen will be attached to
this correct and again you will add more
rx you have an H and two to RM right you
had more rx you get NR 3 you had more rx
you get R 4 and X and this is a
quaternary ammonium salt we will discuss
about this later
yes this is quaternary ammonium salt
this is how it happens you add Alex one
hydrogen is placed with our add one more
rx that is my uncle Hawaii and that
hydrogen is placed with our admin rx you
keep doing it correct and this process
is called m1o lysis this is process
called ml or lysis here the C X mod
breaks that is our X in this slide this
bond breaks by n s3 the ammonia is the
one which breaks this rx pawn or C X 1
so this is carried out at a sealed Q
this reaction is guided sealed to the
high temperature of 373 Kelvin so here
my NH 3 actually is my trojan behaves as
a nucleophile let's see the reaction
mechanism for this so I have let's
suppose NH 3 here nitrogen is a lone
pair of electrons I have red suppose
they react with ch3cl chlorine being
more electronegative try to attract
electron toward its first likely
negative shot carbon get slightly
positive charge and carbon has positive
shots this has lone pair of electrons
this left on this carbon is that black
this carbon and this chlorine will go up
right because chlorine is good leaving
group
so when this what you get is something
like this cs3 now since my in Titan has
given electron to this carbon nitrogen
develops slightly positive charge
nitrogen has a positive charge
nitrogen is electronegative element
nitrogen won't like it somebody has to
leave hydrogen is a good leaving group
it'll leave in this fashion so it will
become CS
hey my dream get back at lone pair
because this will break in this format
and the same reaction happens again if
you react with it suppose c2h5 CL so one
of the hydrogen will be replaced so this
is the reaction mechanism I have seen
are X or cs3 cm chlorine has slightly
negative charge more electronegative
calmness slightly positive charge right
because the chlorine is more
electronegative this nitrogen will
attack this carbon you will get
something like this chlorine will go off
good leaving group mitering it develops
a positive charged nitrogen
electronegative element won't like the
positive charge somebody has to leave
hydrogen leaves right but there is a
disadvantage for this process what does
that see the disadvantage is that if you
see if you add rx to this ammonia you
see you get a first degree 1 degree you
are getting 2 degree you are getting 3
during and evading quarter II ammonium
salt also it is a mixture of one degree
2 degree in 3d their minds and
quaternary ammonium salt and this very
difficult to purify it difficult to
separate one degree 2 degree and 3
degree a minds but if excess of ammonia
is used then my one degree of mine is
produced at a large extent or if extent
excess of rx is used then my quaternary
am I am salt is produced the last extent
if you see logically also during act NS
3rx if you put this as excess what will
happen is this reaction will go till end
correct and you see borock in fact 90%
of our whole and plus 6 miles and but if
you see this reaction issue is excess of
ammonia what will happen is this
reaction will happen only at this point
because we have more of ammonia less of
rx to react right so you will get 90
percent off and it's too
so with that you can actually get 90
almost 90 95 percent but it's still
difficult to produce pure ammonia
because difficult to separate 1 degree 2
degree
Oh mais correct and we talked about the
order of reactivity of haloalkanes we
have already talked about that a lot in
Heller can chapter RI is more reactive
than our BR then our CL right why
because this RI is this iodine is very
big in size if you see iodine is this
much big then you have no mean when we
have growing this is from units this is
Chloe littles high so we compare the
size difference is too high so it is
easy to clue I - is a good leaving group
this is more reactive this is something
which we have seen in depth in the hello
alkene chapter if you want to understand
this you can watch that chapter once
again so this is my amino lysis of alkyl
halide where you have this ammonium you
react with hello alkane and you get
mixture of products and this happens in
373 Kelvin and here nh3 it is ammonia
biggest in the nucleophile this is my
reaction mechanism it happens right and
there's a disadvantage of this process
that is you get mixture of 1 degree 2
degree 3 degree n ammonium salt what I
am resolved but if you want if you can
go for extreme you can have excess rx
you get 90 percent of this ammonium salt
if you use excess ammonia you get 90
percent of this one degree am I
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