In this video we'll take you on a journey. A journey of failure and woe, but with a positive
We've spent the last three days trying to make hydroxylamine, so we'll show you how
we got on.
Here's our two basic starting ingredients in the proportions for our first reaction.
First of all, sodium nitrite. We're starting with 30 grams of the slightly pale yellow
crystal. It's used in meat curing and as a preservative, so you can buy it from specialist
suppliers online fairly easily.
And now here's 90 grams of sodium bisulfite. Again, this is used as a preservative and
in home brewing so it's quite readily obtainable.
The theory is that the bisulfite can act as a reducing agent and convert the nitrite to
a hydroxylamine salt. Let's give it a go.
First we've got to dissolve the bisulfite in a minimum quantity of cold water to make
a saturated solution.
So, we're going to add a little bit of salt.
So first we add a magnetic stir bar.
And now we've measured out 80 mils of cold water to start with.
We'll probably need a bit more.
Let's get this into the beaker with the bisulfite.
And we'll get this stirring to start to dissolve the solid.
We slowly added more water until we had a saturated cold solution.
Nearly there.
Okay, about 180 mils total volume.
We chilled this down so it nice and cool.
Our reaction vessel is going to be this 600 mil beaker.
We'll put a large stir bar in here.
First we add the solid 30 grams of sodium nitrite.
And the instruction we're using tell us that we need 40 mils of water to start off with.
So we measure and add this.
It's very important to perform this reaction in the cold.
Below zero degrees.
So we set up an ice bath.
And we added salt to this to get the temperature down even more.
Okay so now we're ready to set up.
The beaker is in the ice bath and we've a thermometer in the reaction mixture so we
can carefully monitor the temperature.
Let's get stirring.
We're going to add a little bit of salt.
The temperature drops in the beaker.
In order to keep it down we're also going to use some ice cubes in the mixture.
Here's 100 grams of ice cubes.
Let's get these in.
And now our chilled bisulfite solution.
Temperature of the mixture is at negative 10 degrees.
So we'll add the first one.
bisulfite. We added the bisulfite solution in portion with stirrin and not
allowing the reaction mixture temperature to rise above zero degrees C.
Temperature still at negative two degrees C. So this is looking good.
Towards the end we added a couple more ice cubes to keep the mixture below zero.
Here we go.
Complete addition took about 30 minutes, and at the end we've still got some ice floating
around in here.
There's not really any sign of a reaction taking place at all.
We let the mixture stir for another 20 minutes, and then removed it from the ice bath.
In theory this mixture now contains our sodium hydroxylamine disulfate salt.
This is pretty soluble so it's not going to crystallize out on its own.
Well we've got a few options now.
We could try to convert to the potassium salt, which apparently can crystallize out of solution.
But this solution of the sodium salt can apparently also react with ketones to form auxams directly.
So we figured we'd try this out.
The best ketone to use would be methyl ethyl ketone as the auxam apparently forms an insoluble
layer.
But we've only got acetone, so we'll try this.
First we get the mixture stirring.
And now here's 30 mils of acetone, which in theory should be enough to turn the 100% yield
of the hydroxylamine disulfonate into the auxam.
We add this to the mixture.
And now we're going to heat to 70 degrees C in order to allow the conversion to take
place.
Then we allow the mixture to cool slowly.
And leave overnight at room temperature.
Here we go.
Apparently the best way to separate the auxam is by steam distilling it.
So we're going to try to do this just by distilling the mixture directly and seeing if it can
come over with the water.
So here's the big flask.
And the mixture.
We also added some broken glass to stop bumping.
So let's distill the mixture and see what we get.
And here we go.
On heating, we first get some acetone boiling off at a low temperature.
Interestingly, although acetone doesn't form an acetrode with water, we've got a vapor
temperature starting at about 60 degrees and steadily rising to 100.
Pretty quickly the temperature rises to 100 degrees.
We've collected just over 20 mils of distillate.
And now we're going to add the rest of the mixture to the mixture.
Which is a mixture of acetone and water.
So we keep going and distill off the rest of the liquid from the mixture.
This boils at 100 degrees all the way to the end.
At the end we've got a liquefied inorganic salt mixture in the flask.
And distillation slows right down until hardly anything more is coming over.
Right at the end we get some brown sugar.
And a nitrogen dioxide fumes forming in the apparatus.
We stop the distillation here.
We've got about 300 mils of distillate.
We first wanted to see if we could extract anything out of this using inorganic solvent.
So we put the mixture into a separating funnel.
And then tried extracting with 30 mils of dichloromethane.
And then tried extracting with 30 mils of dichloromethane.
After a whole minute of shaking we allow it to separate.
And then drain off the DCM bottom layer.
We then dried the DCM using magnesium sulfate and then evaporated off the solvent on a hot
water bath.
And after all that, the result?
Zero.
Nothing.
The flask was basically empty at the end.
Well it's possible that acetone toxin wants to dissolve in the water more than the DCM,
but it seems unlikely we'd get nothing.
We can't think of any other way to get it out though and to hydrolyze too high hydroxylamine
in such as large amount of water is going to be very difficult.
So we saved this distillate and started over with the reaction.
Following the exactly the same process and creating the new reaction mixture from the
sodium nitrite and bisulfite reaction at below zero degrees.
Here it is.
This time we're going to try converting the sodium hydroxylamine intermedia into the potassium
salt.
So here we've weighed out 45 grams of potassium hydroxide.
In theory the potassium ions should allow the potassium salt to coagulate.
solution.
We dissolved the potassium hydroxide in 50 grams of ice.
And then chilled the solution.
OK let's add this to our cool reaction mixture.
And now we covered this up and chilled it down for 24 hours.
This is supposedly the time required for crystallization to occur.
Here's the result.
Absolutely no crystals.
This means we must be doing something wrong in the reaction.
So we had another go at the reaction only using the smaller scale.
And this time using as little water as possible.
So we mixed 28 grams of sodium bisulfite with 40 mils of water and stirred to form
a slurry.
Not all of the solid dissolved but we left the mixture as it was.
Then we prepared a beaker and a very cold ice bath.
And added 10 grams of sodium nitrite and just 8 mils of water.
And we started off with 2 ice cubes.
Starting temperature at negative 10 degrees.
And this time we added slowly dropwise.
During the first half of the reaction the temperature was at around minus 5.
Then we added the rest.
We added a total of 3 more ice cubes to keep the temperature down.
The large extra cold ice bath helped a lot.
Towards the end, the temperature rose to about minus 2.
And after about 30 minutes we're done.
We let the mixture sit for another 15 minutes whilst we prepared the potassium hydroxide solution.
This time making up a solution using 15 grams of potassium hydroxide and a single ice cube.
We chilled this down and then added to the chilled solution.
It's now almost syrupy in texture with the amount of dissolved solids in.
We left this overnight to chill in the fridge to see if it worked this time.
Hooray! This time we've got a mass of crystal in the beaker.
The texture is a bit like a gel.
So let's filter.
The solid takes a lot of drying on the pump.
Here we go.
Not totally dry but nearly there.
This is 23 grams of white solid.
We're guessing a totally dry weight of somewhere between 50 and 60 grams.
So a 50 to 60% yield of potassium hypoxylamine disulfonate.
We did a couple of experiments which we'll cover in a future video,
but we can prove that this has a large amount of potassium hypoxylamine disulfonate in it
because it is able to be oxidized to a very distinctive compound called fremi-salt.
So this is finally looking up.
Possibly an OTC intermediate.
Let's finally go back to the mixture from our second large-scale reaction.
We added potassium hydroxide and then left for a total of 48 hours.
There's a small amount of crystals, but not very much in here.
So if you want this reaction to work, we suggest small batches,
use the absolute minimum of water and ice,
and use very good temperature control.
And going via this potassium salt rather than directly to an OTC is probably going to be easier
as a potential route to hydroxylamine.
We'll let you know if we find a way.
Stay tuned.