Aldehyde, Ketone Preparation (Part - 8) - Aldehydes, Ketones and Carboxylic Acids, Chemistry Video Lecture - Class 12

hello friends this video on aldehyde
ketones and carboxylic acid part eight
is brought to you by exam viacom normal
fear from exam this is the hydration of
alkynes so all the all kinds except
design except design undergo this
reaction so when you pass through
sulfuric acid maybe 450 percent sulfuric
acid in the presence of SGS F over there
is mercuric sulfate at 333 Kelvin you
get ketones or aldehydes so and it's
right I'm all kinds many pass through
2.2% h2 so4 in presence of Ag so for you
get ketones or LTL and the temperature
has to be 333 Kelvin so let's see the
reaction mechanism for example I have my
are C triple bond CH this is my alkyne
so what happens is I have this 42% is
visible for an NGO and I heat it so what
will happen is this H class use H class
will try to attack this to form a carbo
cation so if you see this bond will
break in this fashion to form a stable
cup you know this bond triple bond can
go on taking this fashion of this
fashion right but if you break in this
fashion you get a stable carbo cation as
per microRNA awful and this H class will
be attracted by this so what you get is
our sea glass double bond cs2 this is a
stable carbo cation correct and then I
have water here so water will come here
H 2 will have lone pair of electron
electron this attracted by this plus
charge will attack on this plus cha
and what you get is RC number 1 CH 2
oxygen Oh H and H posterize comes an
oxygen and oxygen doesn't like the
positive charge will break actually so
you'll get this directly in writing this
correctly because with this child
positives cannot come on let me draw
this one more step so not to confuse you
guys ha she just comes on this oxygen it
is not happy right so this bond break a
nice person will come out so what you
get is this guy correct now now Masek
will happen now let me draw the
structure once now magical happen now
what happen is this H will break so
again it will break in this fashion you
will get a slightly negative charge and
this will also break in this fashion
right so this gets a negative shock this
gets a positive charge they'll form a
bond and this h class will attack here
so this carbon will are dying this guy
it when this fashion hope you understand
see this model break and this carbon
gives slightly positive charge that you
negative charge here and this bond will
break so H will become H plus and were -
OH - MC can form a bond and this h plus
will tag this guy so what you get is our
C double bond C edge this is what you
get correct this is the mechanism for
this reaction so we want I can take one
example for example if I take CH 3 DC
triple bond CH so again in this I do the
same thing almost 40% h2so4 n + GS o 4
so what you get is CH 3
double bond CH 3 this is my propane on
this is what you get
so by hydration of alkynes we can easily
get ketones or to the height the next is
by heating calcium salt of carboxylic
acids let's see this method of
preparation of aldehydes and ketones by
heating calcium salt or carboxylic acids
also God distillation of calcium salt or
Khan carboxylic acids so generally what
happens is you take this calcium Kelsall
of carboxylic acids you heat it very
hard what you get is calcium carbon why
you get this because calcium covered is
very very stable couple very stable
compound and to me how do you get this I
won't be giving you the reaction
mechanism but and just to give you fair
idea of how it works for example I have
a ch3 on it suppose are any calcium RC o
minus 2 C this is my cluster there's my
calcium salt of carboxylic acid right
now in this case if you see our co-
C is here from this if you take out
caco3 what happens is there are two of
these right so typically if you've seen
a structure of this calcium sort of the
carboxylic acid is something like this
calcium o ce o-- r --o c over right from
this if you want to find take out
calcium carbonate caco3 you have to take
out caco3 this must correct
this is easy three if you see this c su
3 is this right so from this if you take
c su 3 what you get is this
what you get is our see this reactions
happen the very very high temperature so
there is no reaction mechanism it is in
the sub Gajic here
CSU from this you are taking out caco3
CA C and three oxygen so what you get is
our C you are correct now if you have a
myth Noack calcium salt of calcium form
of methanoic acid and one calcium salt
of non methanoic acid what you get is
aldehyde correct and if you have calcium
sort of norma throwing acid you get
ketone for example in this case if I
have example a issue if I if I take this
guy - C correct and this I have to also
adds eh three or let us take this only
right if you heat this what you get is
CH you get HC o h plus c su 3 c this is
nothing but methanol aldehyde here if
you take one of these as again my non
metallic calcium salt another as non
with Rhoni calcium salt in this you are
decade is ch3cooh also you did other
company l think you'll get CSC COCs
three also but you get this also one of
the products right you get lot of rights
and now if you take only the myth non
with knowing salt for example this case
right and if you heat this CSU 3 will
come out and what will be left is cs3 co
cs3 it's correct if you see from this if
you take out CSU 3 you get this so you
get aldehydes you get ketones if you
take a myth Noack salt or Kasim sort of
methanoic acid you get aldehydes you get
calcium salts of non methanoic acid you
get if you take combination of this
example here this is the combination of
calcium sort of methanoic acid Kats
involve nan is my guess indicate
aldehydes also your head you will get
ketones also you will get you will get a
lot of product you will get three
product I see ok so remember the
reaction mechanism is not important here
what is important here is given the
reactants you should be able to take out
caco3 and form a product and why you
take out see you see because if it is
very very steep income one's very very
stable compound the next is will try to
prepare aldehyde ketone from grignard
reagent so here just understand that if
you take hydrogen cyanide then you will
get if you get hydrogen cyanide so what
you get is earlier and if you take any
alcohol tonight what you will get is
ketone I will explain this just since is
critical so I'm reading in top now let
us see the reaction mechanism let's see
for aldehyde so I have taken out reagent
grignard you know as rmgx where r has a
negative charge and this guy has a
positive charge right it looks like
pasta and I can take ACN because for LD
I'd I will take SCN SC triple bond n
correct now what will happen is nitrogen
is more liquid introduced right or title
promotes itself carbon will draw it
slightly positive charge 9 units likely
negative charge this post shows this R
is R - R -
this carbon and nitrogen this bond will
break in nitrogen will attack this mg X
so what you get output here is my C with
the H this double bond will break into
double bond and this carbon will get my
R and this nitrogen will get my mg X
correct so once I am done with this I
had to put water in this now if I put
water in this what will i get is
aldehyde so I put water in this let's
see what happens just for simplicity I'm
assuming water has X plus and H minus
sign right this bond will again break in
this fashion nitrogen is more
electronegative so this will give us
like a negative charge and really
slightly positive charge so os-
will attack this carbon and nitrogen
will attack this right so what you need
is HC u becomes H here is n we have h mg
X and I have I this is what you get
correct assuming my HOH breaks in this
fashion now what will happen is this
nitrogen will try to come out correct so
what will happen is this o H bond will
break and you get a double bond here so
let's see the reaction mechanism let
this boa chair so Oh H will go off in
this fashion right h plus will go up
this will be native charge and this guy
this bond will also break right so this
bond will break in this fashion so that
this gets a positive charge here this
bond will break in this fashion and this
hydrogen naturally negative charge in
this nitrogen will attract this hydrogen
so with this what you get is our C
double bond
ah sorry this is h HC double bond here
why because this bond will break it will
have a negative shot this bond will get
coupled with a positive charge so oxygen
negative charge carbon positive form a
bond and this nitrogen has now has
hydrogen two hydrogen in mgx correct now
again you add water is let's assume e
what are the S Plus H - just for
simplicity so again what will happen is
this nitrogen since it has lone pair
it'll attract back on this h plus and
this bond will break action this bond
will break in this fashion so what we
get is silica - 3 and this will become
an G X and here which will come this
bond breaks correct and this is what you
get so total you get is our CH and this
is mine aldehyde and this came and I
have used H C n so you see if I use HC n
again this H is my this is so she'd of H
if I use our hair I get by correct let
me show you one example for aldehydes so
let's suppose I have this CH 3 mg I is
my ignore agent in that I use HC n so
what you get is cs30 h right this is
what you get plus 10x3 plus mg i o h
similar reaction for ketones for ketones
if you see I have my RNC X and then
instead of using SCA I will use RC n
what you get is this bond breaks and
it appears our - you get our - see our
comes here our - mdx plus you get this
mg X correct and on this if you add
water you get our - C double bond o our
this is my ketone plus an s3 + mg X
squash reaction mechanism exactly
similar to what we have discussed just
now right so for example like in show
you an example at C is 3 mg I is my
grignard reagent react with CH 3 C table
would n know what you get is C is 3 C
here you can see is 3 double bond in an
mg I on this if you add water what you
get is CS 3 skin double bond CH 3 + MZ i
h + Maria this is the reaction mechanism
forward preparing early height and
ketone from grignard reagent
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