We are gonna have a look at -- today, something that's been hitting the headlines.
And we're gonna be talking about this compound here, which it rejoices under the acronym:
2,4-DNP. So that translates to 2,4-Dinitrophenylhydrazyne.
You've particularly sort of appreciate it because its trivial name is Brady's Reagent
but it also rejoices under the trivial name of Bosche's Reagent.
Well, I guess, what we'd like to start the story with is taking you way back
to the dawn of organic chemistry, in maybe the 1750's through about 1980's.
All of the modern techniques that --as a student or as a member of the public that we learn about,
before the martyr of modern analytical techniques, are not available.
In fact, the only technique that's available is to measure the melting point of your compound,
and that kinda could create some difficulties for you.
I've got an example here that we can look at this morning.
So this is a popular compound. This is a compound of benzene, it's a derivative
and it has an aldehyde group on it.
But, as you can see, there's gonna be an intrinsic problem with
measuring the melting point of Benzaldehyde. It's a liquid.
And if melting points are the only thing you can do, you need a way to be sure that everything that is in
that aldehyde or carbonyl class (....)
solid that you can then even measure the
melting point even in 1750 and black the
essence of the ladies reagent or DMP
something that you can be sure that the
correct an aldehyde or ketone with to
give you a solid crystalline reagent and
back in the day it would come as a solid
so what we're going to do now is we're
going to look at the original
formulation of the BMP Brady's reagent
as it was supplied up until I guess
probably about a year and a half ago so
we're in here so we're going to do a bit
of mining because this has been packaged
up this is just secondary containment is
the plastic outer shell
and now we can get through the least in
its original form and you can see is the
Dean for the dye that the end for the
Nitro and there's the piece of the
senile hydrazine Pete and Pete gives you
the ladies reagent if the compound is
formulated correctly it will be
completely spaced and very bored we have
no need to worry but if it's dry then
that's when all the fun and games and
excitement starts but I've deliberately
selected / compound where I believe it
is dry so I'm just going to point that
away from me a little bit and just open
up gently so the compounds not terribly
volatile so I'm handling listen I could
but what we're going to do is probably
get a sheet of paper in here so that we
can put a little bit out so that you can
feel and what you should see if you can
spoon some out is a highly bright orange
now these are not Cristal's these are
aggregates where the small little
microcrystals of all started to come
together as its drying out when it dries
out then the region can become more
unstable it can suffer an autocatalytic
decomposition the order catalysis is
where the product of a reaction
encourage the reaction to become faster
which generally more products so that
becomes even faster and of course that's
how you get a runaway reaction and
that's what we call an explosion and
we're going to test out a little bit
later but let's actually focus on why
the reagents used and why it's useful
and let's take you back again to the
1750 and if you remember we had this
compound benzaldehyde we're clearly we
don't have a solid so we would like to
make a solid derivative not we would
have to take this solid and we would
have to dissolve it and that'll take us
a little bit of time so what we're going
to do is use the luxury of modern
chemistry and what I've done here is
actually so influenced me to his one eye
pattern
so this is just a solution of this
orange compound i put it into solution
and so what you should see here i hope
is that bright or institution come up
right okay so we're going to try and
turn I've been out of hiding to a into a
solid now i just mentioned that canvas
like to do all of their reactions in
solution so we're going to use methanol
we're just going to use that as a
solvent for the reaction so we need to
get both are orange hydrazine and our
carbonyl compound in the same solution
so I'm going to take some benadryl
divide here and what I'm going to do is
to a not terribly stoichiometric
reaction clue we're going to take
that'll probably about the about 250 200
300 million dancing like that will put
that into the solar put the lid back on
here and now the high desert very nice
smell of almonds but it's like toxic
toxic and now we need to switch and see
if we can get this to maker of
precipitate so let's see
benzaldehyde got a mass of about a
hundred we're about two million miles in
here this is about point two molar so we
need a illegal about this with the rate
of reaction of DMP o Brady's raging with
aldehydes depends on the substrate and
it can take anything from instantaneous
up to several hours
alright so let's just stop there
oh look there you go
so as you can see we've got almost
instantaneous reaction we've produced
from our original liquid benzaldehyde a
large clump of a bright orange-yellow
derivative chemist like to use names to
describe the derivative we started with
the hydras leave for this derivative of
the hydro-zone ok so we've talked a lot
about the chemistry of the MP and white
really useful but it won't have escaped
your attention that in media recently
there's been a lot of concern over
Brady's reagent pnp as a potential
source of the explosion the compound as
it was originally formulated damn
perfectly safe in the modern version
that we've shown you perfectly safe
the compound does have a reputation mode
for being what is called shock-sensitive
meaning that is the compound is
subjected to friction or sudden energy
through an impact it can detonate that's
not so well described actually in the
scientific literature and so in the
cause of science
what we're going to do is try and make a
brief investigation of a small and
therefore potentially safe scale to
indicate what the degree of shock
sensitivity is as formulated in wet that
shouldn't really be that much shock
sensitivity and ladies region but like
there's very little data and we're not
going to take any chances for I I'm not
gonna put on not just a face mask but
this is an explosion facemask and it
exposed it will protect my face still
and I'm gonna gonna lose any fingers so
i'm going to go for some protective
gloves as well to chest the toxin today
we are going to use this highly
expensive scientific piece of apparatus
available from any good hardware store
and we're going to strike the compound
not excessively hard because it should
lead that if it's going to go so I'm
going to give it a light tap and then
we'll see 123 that I think it's me
missing so we'll do that again
12
three we struck the compound you might
want to come in and have a look at back
and free here at the black this is where
it was struck with a hammer quite
vigorously no effect whatsoever you can
make the comparison against the material
that jumped off the front
these are exactly the same color and
that's quite a decent strike
okay from what we should do now is let's
try the compound out and see if it makes
a difference
so again the literature is not too clear
and in view of safety concerns
we're going to be a little bit vague
about how long we're going to drive is
compatible we're going to put it on this
hot plate that you can see in the back
of the hood you can see the red flashing
light indicating that the hot plate is
heating and if you look closely at the
dials here you can see it said it just
over 100 degree C so that should drive
offering water and then we'll run our
shop test we're gonna put that on the
hot plate and now it's my turn the fire
code retire to a safe distance
ok so we're backing part two of the
great shock destination story so while
we've been away having a cup of tea
what we have left is our hot plate which
you can see in the background there and
we've been cooking up rtmp so we're at
the top here and on 321 this compound is
not excessively shock-sensitive ok but
what i should add at this point of
courses we've done this under very
controlled condition was done this with
a very small amount of material the
compound has a reputation for shock
sensitivity therefore there have been
detonations in the park
clearly we've done this for you today so
that you can see and feel confident in
that in the chemistry but that i would
advise you to take in 14 pound sledge
hammers and Dustin's full of this stuff
expand very rapidly one of the things
that Idol was interesting is that when
the bubble catches fire burning gas
continues to move up