In today's video we're going to prepare a useful reagent, solid sodium ethoxide, which

can be used in some organic reactions.

To start measure out 100 ml of ethanol.

You can use slightly more than this if you want and the initial reaction will go faster,

but you'll only have to distill it off later.

Place this into a dry 500 ml flask, and set this up with a reflux condenser running cold

water.

You don't need heating initially as the reaction will generate its own.

But later we'll need to apply heat to reflux as well.

Now measure out 10 grams of sodium metal in a chunk like this.

As always work quickly with sodium because it tends to rapidly react with atmospheric

moisture.

Dry the sodium and make sure it's free of mineral oil from storage.

Cut into small chunks.

The smaller they are the quicker.

They will react.

Now temporarily remove the condenser and add the sodium to the ethanol in the flask.

Replace the condenser again immediately after addition.

The sodium reacts vigorously with bubbles of hydrogen gas being produced.

And the mixture starts to get hot quite quickly.

Soon the ethanol will start to reflux in the flask and in the condenser.

After about 40 minutes the ethanol has mostly reacted and the liquid is becoming slightly

viscous.

So we now heat the flask to keep reflux going for a further 30 minutes in order to ensure

all sodium metal has reacted.

The liquid turns a slight yellow color during this time.

Once it's all reacted.

Set up for simple distillation.

We'll need for a thermometer but using a vacuum will help enormously in this case.

The ethanol comes off quite rapidly.

And you can start to see some white solids depositing on the sides of the flask.

Soon a crust appears on the liquid and we have reached a saturated solution.

This is where our vacuum comes in useful.

Switch on.

But only temporarily.

As the solvent is expelled the solid remaining forms the foam in the flask.

Repeat this a couple of times and you should end up with a stable foam that doesn't collapse.

This gives us a lot of surface area for drying and makes the final product easy to remove

from the flask.

Leave the vacuum on now for a good 45 minutes with a little heat in order to remove all

ethanol.

We recovered around 75 mils of ethanol from the mixture, having added another 20 mils

during reflux to make the sodium react faster.

Here's the flask containing the product.

You can see there's a top layer which has become dark brown in color.

We scraped this off the top of the product in the flask.

We're not sure why it has a brown color.

Possibly impurities.

We're not sure why it has a brown color.

And here's our dry product.

24 grams of sodium ethoxide as a light and fluffy crystalline powder.

This is an 80% yield on starting sodium metal.

It's cream colored and probably contains a small amount of sodium hydroxide as well but

we think it's relatively pure and should suffice for the reactions that we want to use it in.

It's a very strong base.

So don't get it on your fingers.

And here's our dry product.

It doesn't react violently with water.

There's a hissing sound and some heat given off.

But not much more than adding water to sodium hydroxide.

Stay tuned to see some reactions with our new reagent.

We'll be right back.

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