If you've been following our videos, you'll know that we recently broke another thermometer in a rather nasty incident with a ketone.

Well, we salvaged the mercury and here it is. It's very dense and just this tiny drop weighs nearly half a gram.

So we figured we'd use it in an interesting experiment.

Last time we used plain nitric acid to dissolve it, but it wasn't so successful.

So this time we'll try something different.

Here's some 68% nitric acid.

And now we're going to add to this about the same amount of 36% concentrated hydrochloric acid.

The mixture fumes strongly and slowly turns yellow as it sits in the beaker over a few minutes.

What we've made here is called aqua regia or royal water.

So-called because it's great at dissolving metals, including gold.

So this time let's use this with our blob of mercury and see if it will react.

The surface has tarnished and it's not quite so blob-like anymore.

Let's get some more in there.

It's not as fast as we thought it might be, but it's definitely doing something.

Weird.

A bit more aqua regia and then used a glass rod to stir the mercury in the mixture.

And after about 10 minutes of stirring all the mercury dissolved.

This is great.

And better than our previous attempt.

Okay, so let's get this diluted down and then neutralize the solution.

Here's about 50 mils of water.

And here's our acid-mercury solution.

Now we make up a saturated solution of sodium carbonate in water.

Here's our diluted mercury solution.

We've got this on a magnetic stirrer and with a stir bar in there.

And our sodium carbonate is ready.

We'll add this slowly and as we do so there's some effervescence as the carbonate reacts with the acid producing carbon dioxide.

Eventually, a single drop produces a transient yellow color of mercury carbonate.

So let's check the pH.

It's around 6.

Nearly neutral, so we're done with neutralization now.

Okay, here's our mercury solution and as before we're going to see if we can use this.

We're going to use this to amalgamate a metal for a nice organic reduction reaction.

But this time we're not going to use aluminium.

We're going to use zinc.

Here's 50 grams of zinc powder.

We've broken up any larger lumps so it's nice and fine as you can see.

When amalgamated, zinc together with hydrochloric acid can react with aldehydes and ketones in a reaction called the Clementsan reduction.

As you can see, the carbonyl group is converted to an alkane.

And we're going to be trying this out on our favorite aromatic aldehyde, vanillin.

We add the mercury solution we prepared to the zinc.

And then get the mixture stirring well.

Zinc is quite a bit less reactive than aluminium so we're not sure if we're going to see anything interesting happening here.

We're going to leave this stirring for an hour.

In the meantime we can prepare our other reactants.

Here we've weighed out 15 grams of crystalline vanillin.

Remember that vanillin is an aromatic aldehyde which is similar to benzaldehyde.

But it has methoxy group and hydroxy group as substituents on the aromatic ring.

Here's our solvent for the vanillin.

45 ml of ethanol.

Let's get this into a 250 ml capacity beaker.

And now we add the vanillin.

As it dissolves the mixture becomes quite cold.

It takes a bit of swirling and allowing the mixture to warm before everything dissolves.

Here we go.

Now to this ethanolic vanillin solution.

We add 100 ml of concentrated hydrochloric acid.

The vanillin stays in solution and the mixture turns a yellow color as you can see.

We've covered this up and we'll reserve it ready.

Our zinc has now been stirring for just over an hour in the mercury solution we created.

There's not much of an obvious change.

Although when we allow the mixture to settle we notice that the zinc has transformed into a very fine uniform powder.

We set up to filter the zinc powder.

We wash with a little cold water.

And then dry it until it forms a semi-solid paste.

Okay let's get set up for the reaction.

We're going to use a large 1 liter flask on a hot plate.

Equipped with a large magnetic stir bar.

We're just using the stir bar we used from the zinc preparation.

First we transfer the zinc paste we filtered into the flask.

Then we wash the filter with about 20 ml of water and use this to transfer all the zinc.

Now we set up an addition funnel on top of the flask.

It's pressure equalized so that any gas produced can escape.

Double check the tap is closed.

And then add the vanillin solution we prepared.

Okay we're ready to rock and roll now.

We've got the zinc paste stirring in the bottom of the flask.

So now slowly we start the addition.

Some smoke like vapor appears in the flask very quickly.

And the mixture starts to heat up.

We keep the addition slow but steady and soon we can see droplets of condensation inside the flask.

We keep the addition going so that the mixture doesn't boil but gently refluxes inside the flask.

We leave this running and the total addition takes just over an hour to complete.

We notice that the yellow color of the vanillin mixture disappears as the mixture reacts in the flask.

Once addition is complete we measure out another 20 ml of concentrated hydrochloric acid and add this to the addition funnel.

Then we continue adding this drop wise.

At this point we switched on the heat to the hot plate and made sure that the mixture was stirred just under the boiling point.

Once acid addition was complete we continued to heat and stir for the next 45 minutes.

Then we allowed the mixture to cool down.

We added some ice to help cool it and noticed that the mixture turned a milky color.

Okay our reaction is complete.

So let's filter off the solids and collect the filtrate.

We transferred the solids back to a beaker and measured out 25 ml of dichloromethane.

We washed really well and then filtered again.

Our filter is ready.

It should now contain all our product.

So we transferred to a separating funnel.

The bottom dichloromethane layer is slightly yellow colored as you can see.

So we drained this off into a flask.

And then extracted the remaining aqueous layer with a further 25 ml of dichloromethane.

We shook the mixture well and allowed to separate.

And then drained the DCM layer off into the flask.

Here's our DCM solution.

We dried it using some anhydrous magnesium sulfate.

We noticed that it seems to turn yellow over time.

So it's possible our product is air sensitive.

We decanted the solution into a pre-weighed dry flask.

And then evaporated it.

We evaporated off the DCM solvent until we got down to a constant flask weight.

Again we noticed a slight darkening of the solution as it was evaporated down.

Here's our product.

9.6 grams of crude creosol isomer as a yellow colored oily liquid.

There's a small amount of aniline dissolved in here but we can smell that it's not much.

The aroma is very interesting.

It's phenolic but has a woody slightly smoky and sweet candy like quality as well.

Reminds us of some old fashioned candies.

For a pure product some more work will be needed.

But we're pleased with this reaction and it seems to have worked well.

Thanks for watching and stay tuned for more interesting reactions.