We wanted to make some more bromine for some experiments so we ordered some sodium bromide.
And this is what turned up.
It's not sodium bromide, but sodium bromate.
Oh well.
They charged us the same price so we're not sure if that's good or bad.
But anyway, here's 100 grams of sodium bromate.
It's a quite dense heavy crystalline solid.
Well we don't know much about bromates so we did a few experiments to see if we could get the bromine out of them.
Obviously we were excited to see if our sodium bromide would work.
So sodium bromide reacted with concentrated sulfuric acid in the same way as chlorite and produced some weird bromine dioxide.
So let's try it out.
Here's some bromate crystals.
And a few drops of sulfuric acid.
Wow.
That is some serious hardcore bromine.
And evolution.
So we figured awesome.
It didn't explode so let's try it on a larger scale.
Much larger.
We assembled an unusual apparatus as you can see here.
Let's do a quick tour.
First of all we've got the 500 ml flask for the reaction and it's equipped with a magnetic stir bar so we can stir the mixture around.
On top of this we've got the separating funnel in the main arm.
And some of the flask so we can add the sulfuric acid very slowly.
Then we've got the gas outlet leading to an adapter and down into a condenser for the bromine.
It's a nice long condenser so we can hopefully condense the bromine efficiently.
We never have much luck with this so we'll see.
And then at the bottom we've got a cool new adapter.
New glassware alert.
Thanks to our Patreon supporters.
And then this cool new funky adapter leads to a small flask at the bottom for hopefully collecting the condensed bromine.
And the adapter's got a hose attached to it which leads to our ventilation outlet.
Note that this is not optional.
It's absolutely 100% mandatory as you will see.
Okay so first let's get our flask loaded up.
We're going to use 100 grams of the sodium bromate and see what sort of bromine we get.
The bromine yield we get out of it.
Okay it's all in.
So now let's get the addition funnel back on again.
Let's get the powder stirring.
Our cooling water for the condenser is ice cold and we've really loaded up the water with ice.
Let's start circulation.
And we need our receiving flask to be super ice cold as well.
So we've got lots of ice in here and we'll add some water and salt as well.
The condenser is frosting up with the humidity so it's definitely nice and cold.
Okay now for the sulfuric acid.
We have to confess we don't really know exactly what the reaction is.
But we will use 50 mils of concentrated acid which is about a 1.4 molar ratio to the bromate.
Double check the tap is closed.
And let's get it in.
The 1.4 ratio should be enough to convert everything to chromic acid.
And then do a bit of dehydration as well.
So we figure this should be enough.
Okay well here we are.
Everything is ready.
So it's time for the moment of truth.
We have ignition.
There's an initial pressure blast of bromine vapor which instantly fills the entire apparatus.
The reaction is incredibly fast.
And it's ventilation time.
We keep the acid addition slow and steady.
And we quickly get a red liquid condensing and then dripping down into the receiving flask.
Okay here we go.
Complete acid addition in about 15 minutes.
The reaction continued in the flask.
But soon died.
And we couldn't see any more drops being formed.
We could heat the mixture to see if more bromine will come off.
But we decided to stop here.
And here's our collection flask.
We pre-weighed it so we know we've got 22 grams of crude product in here.
There's very little water droplets or anything else so it looks fairly pure.
And that's a 42% yield on the bromine in the starting bromate.
Not too bad for a first attempt.
We'll extract this using an organic solvent and save it for future reactions.
If we were to do it again we'd probably try a slower acid addition.
Especially to start with.
And perhaps somehow even stronger cooling or even a double condenser setup.
Thanks for watching and stay tuned.
For more reactions.