In the previous video we prepared ammonium methyl sulfate via the reaction between sulfamic

acid and methanol.

At temperatures above 200 degrees C this apparently undergoes a reaction whereby it isomerizes

into methylamine hydrogen sulfate.

If true this would offer a very OTC and fairly easy way of making methylamine.

So first let's do a small test to see if this has any validity.

So let's check it out.

Here's our setup.

We're using an oil bath equipped with a thermometer so we can record the temperature

and a borosilicate glass test tube to do the test scale reaction in.

Here's one gram of our ammonium methyl sulfate crushed up into a powder.

Apart from this we're using it exactly as we prepared it from the previous reaction.

It seems to be slightly hydroscopic, so don't allow it to contact the air too much.

Okay let's get this into the test tube.

And we'll use a metal rod to pan it.

the solid down at the bottom so that the heat is conducted through better and we've got

a better chance of reaction. So now we'll start heating the oil bath. Apparently the

best results are obtained above 250 degrees C and at 275 degrees C the conversion is nearly

quantitative. We've got some nice patterns in the oil as it heats up. The first thing

we notice is that there's some liquid condensing on the inside of the test tube. We know from

the previous preparation of ammonium methyl sulfate that there's some methanol still left

in the solid, so this is probably methanol boiling off and condensing. After a while

the solid has melted in the tube. The temperature at this point is just over 100 degrees C.

We continue heating strongly to get the temperature up.

Unfortunately the temperature is still very low. The temperature is still very low. We

continue heating strongly to get the temperature up. Unfortunately our oil bath starts to smoke

quite badly but we'll continue anyway. We continue until the temperature in the oil

bath is 270 degrees C and then switch off the heat. We allow the test tube to cool down

and the product remains liquid, although becomes more viscous like a resin as it cools. We chilled

it down and soon it crystallized into an off-white colored solid as you can see here. It's

got a slight sulfurous aroma to it as well. We added a few mils of water to the test tube

and the solid dissolved pretty easily to form a solution. Ok let's test now to see if this

has got any methylamine salts in it. If we add a strongalkali solution to a methylamine

salt, methylamine gas should be produced. So let's make up the strong hot solution of

sodium hydrazine, which can be found in your found in the salt area. And make it very hot.

oxide and let's add a bit to our product solution very rapid bubbling and a gas

produced well this could be ammonia so let's see if the gas is flammable

ammonia isn't flammable in there but methylamine is and the aroma of rotting

fish is our final clue so our test is positive this works

okay now that we proved the theory let's see if this can scale up and give us a

pure product here we've got 155 grams of ammonium

methyl sulfate and we've placed this into a beaker on a hot plate

equally

with a thermometer we've chosen a larger beaker so we get a more constant

temperature in the mixture close to the hot plate on heating pretty soon the

mixture starts to melt and bubble just as it did on the small scale once the

mixture melts the temperature rises rapidly

and as the temperature rises the bubbling changes slightly it doesn't

look so much better than it did when we put it in the beaker so we're going to

ethanol coming off, but more like effervescence of some sort.

We continued to heat, and soon some white fumes started to be produced from the mixture

as well.

We placed some aluminium foil over the top of the container to avoid any product loss,

and to keep the heat trapped in.

Now at 250 degrees C, the mixture is still bubbling quite a lot as you can see.

Interestingly though as the temperature reached 270 the bubbling seemed to die down and then

stop.

We got up to a maximum temperature of 280 degrees and held for about 10 minutes before

allowing the mixture to cool down.

We covered the beaker in plastic wrap just in case the product is hygroscopic.

Pretty soon on cooling the mixture started to become viscous like before, and then solidified.

You can also see some crystals forming around the sides of the beaker.

A small sample placed into a glass petri dish did absorb moisture from the atmosphere quite

quickly and turned into a small puddle after about 15 minutes.

We've got to assume at this point that our product is a combination of aluminium methylsulphate,

methylamine bisulphate, and perhaps side products as well.

We're going to dissolve the crude product in water.

We're using 80 mils here.

The solid is pretty tough, so we used some heating and a magnetic stir bar to help the dissolution process.

This took about 20 minutes.

Once the solid has dissolved, we're ready to do the next stage of purification.

We're going to use a base to convert the methylamine into its gaseous form

and then absorb it into water to make a solution.

We've got a large conical flask set up with a magnetic stir bar on a hot plate.

First we pour in the dissolved product solution.

Still slightly warm.

Here's our setup.

We've got the ground glass adapter attached to the top of the conical flask which has an addition funnel on top.

Then there's a gas take-off adapter with a plastic tube attached.

And this leads to a small conical flask with a glass tube.

To bubble the gas through.

Both methylamine and ammonia are extremely soluble in water

and we're using about 40 ml of water in the flask to dissolve any gas produced as it comes over.

To convert our methylamine bisulfate into methylamine gas,

we will need to add two equivalents of sodium hydroxide.

We're going to start off using 70 grams which is about a 1.5 ratio and see how we go.

We don't have a 100% complete conversion.

Here's about 150 ml of water and 100 grams of ice to dissolve the sodium hydroxide.

This makes a nice strong solution.

Ensuring first that the cap is closed.

We place this in the addition funnel.

Okay now we're ready for action.

We're going to take the flask so that the contents are quite hot but not actually boiling.

This will help drive off the gas produced.

So let's start adding the sodium hydroxide to the crude product mixture.

There's a smoke produced initially in the flask.

And up close you can see and hear that each drop is generating gas in the flask.

And after a while we can see that the gas produced is mostly dissolving in the water.

Once addition was complete we removed the addition funnel and then heated the mixture more strongly to expel any gas.

After about 20 minutes this seemed to be complete so we allowed the reaction flask to cool down.

Remove the glass tube from the water in order to avoid suck back.

We got a small portion of the reaction mixture and tested the pH.

Slightly acidic.

Which means that we potentially still have some product remaining in here.

So we mixed up another 25 gram solution of sodium hydroxide using ice water.

Then we set up the reaction again as before to see if we could get any more gas produced.

We added the sodium hydroxide pretty rapidly and then heated the mixture to boiling point for a good 30 minutes.

You can see there's still quite a lot of soluble gas being produced and coming off.

We also noticed both during the first and second half of the reaction that the water heated up quite considerably as the gas dissolved.

Which means that the volume increased in volume and weight.

Okay we're finished now so we allowed everything to cool right down.

Here's what we got.

A rather stinky aqueous solution containing the mixture of ammonia and methylamine dissolved in it.

Next step is going to be to neutralize these into the respective salts so we can separate them.

So we measured out about 20 mils of concentrated hydrochloric acid.

The combined fumes from the two liquids create quite a bit of smoke.

We add the hydrochloric acid to the cooled product solution.

It reacts rapidly giving off heat and some localized bubbles as you can see.

You can blow nice toroidal vortices using the smoke and a pipette.

Okay we're nearly neutralized now.

Remember to measure the pH as you go.

We place the solution into a large beaker so as to maximize the surface area.

And then continued neutralizing using hydrochloric acid until just acid.

Some plastic wrap helps avoid too much smoke.

Let's check the pH.

Slightly overshot the mark, but this is okay.

Now we're going to heat the mixture in the beaker strongly and evaporate off all the water.

After a while the mixture will start to form a white crystalline solid as the solution becomes saturated.

Keep heating.

You'll get a liquid forming again.

And at about 130 degrees C there is very little water remaining in the mixture.

So allow to cool and cover with plastic wrap.

This is important because the product is very hygroscopic and will absorb water rapidly from the atmosphere.

We build a special DIY desiccator filled with calcium chloride in order to make sure the product remains dry.

Well we've now got a mixture of ammonium chloride and methyl ammonium chloride.

The latter is much more soluble in ethanol, so we'll use this for our final separation.

Here's 14 ml of warm ethanol.

Add to the solids.

And gently heat on a hot plate for a few minutes.

Then filter the hot mixture quickly.

As the ethanol cools you can see crystals of product separating.

Wash with another 25 ml of hot ethanol.

The fine crystals left in the center are ammonium chloride.

And the crystals forming in the ethanol are mostly methyl ammonium chloride with a small amount of ammonium chloride.

Chill this mixture down for a few hours in order to maximize the crystals.

Looking good.

And now we filter one last time.

Get them dry, but not for too long otherwise they'll absorb moisture.

The filtrate does contain some product, and you could evaporate this down further to obtain more.

Here's our product.

30 grams of nice flaky methylamine hydrochloride crystals.

It's still slightly damp with ethanol, but the maximum yield then if this was dry is 37%.

So probably around 30% for a dry product.

We're quite pleased with this.

This is our first time trying this method.

It's likely that the method can be optimized a lot more.

Thanks for watching and stay tuned.