In this video we'll prepare ortho-toluidine by reducing ortho-nitric

toluene using tin metal and hydrochloric acid.

Set up a 500 ml flask with magnetic stirring.

First measure out 26 ml, which is 30 grams of nitro-toluene.

Note that all isomers will work in this reaction.

We're using the ortho-isomer.

Next measure out 49 grams of tin metal.

Here is, you can see we are using small tin shot.

So, long as the pieces of metal are small enough,

to, be stirred magnetically, then it will work fine.

Add the tin metal to the flask.

Then add the nitro-toluene and begin stirring.

Set the flask up with reflux condenser and make,

sure that the water passing through it is quite cool.

Now have ready 110 ml of concentrated hydrochloric acid.

I've split this into two batches.

The first here is 60 ml.

Now, with ventilation running, add an initial 10 ml,

of, the acid into the flask.

Stopper the flask and watch carefully.

1,2,3,4,5,6,7,8,9,10.

The temperature will rise.

rapidly, and the mixture will start to boil. The contents of the flask will also first go cloudy, then change to a brown color.

As the mixture boils, refluxing will automatically begin.

As the reaction dies down, add a further 10 to 15 ml of acid, and it will spring to life, once again.

Complete addition should take around 45 minutes towards the end.

You'll notice that the reaction is slower in the final.

30 ml of acid.

Can be added in one portion.

After complete addition, you'll notice that most of the metal has dissolved.

Turn on the hot plate and reflux the mixture for a further 30 minutes in order to complete the reaction.

You can test that the reaction is complete by placing a few drops into water.

There is no cloudiness or oily nitrotoluene present.

Now we need to freebase our toluene by making the reaction mixture alkaline.

Prepare a solution using 90 grams of sodium hydroxide and 150 grams of ice.

Once refluxing is complete and the reaction mixture has cooled slightly, carefully and slowly add the hydroxide solution to the flask with stirring.

Add a touch of coyote resin to the flask toPar however soft you like.

You'll see yellow and white precipatates being formed and the temperature will rise if the mixture boils then allow you cool before adding more hydroxide

On complete addition, the mixture looks like this.

You can see a layer of our product forming on top of the mixture.

Do not try to filter this as it will block any sinter or paper, instead, place it in

a larger flask and set up for distillation.

The steam from the water boiling will bring over the product.

Turn the heat up and get the mixture boiling quite vigorously.

As the water boils you'll see a milkiness or oily drops in the condensing liquid.

This is toluidine steam distilling over.

You'll also see oily droplets appearing in the distillate.

Keep the distillation going and top up the water in the boiling flask.

Once the volume gets too low in, the liquid starts to bump.

Once the distilling liquid looks like plain water, keep going for 20 minutes longer, then

turn off the heat.

The total time required to distill is around 3 hours.

Taluidine free base is slightly soluble in water.

To force it out we now add enough salt to the distillate in order to get the water layer

saturated.

Add salt to the mixture and shake the flask, keep adding until the solution is saturated.

The toluidine will clump together and form a top layer on the liquid.

Place the mixture into a separating funnel and separate the toluidine top layer into

a beaker.

Then take the salt water layer and place it back into the funnel again.

Wash the water twice with 20 mils of water.

Each time using dichloromethane to finally rinse the funnel with a further 15 mils of

dichloromethane.

Combine the toluidine and dichloromethane portions in a beaker and add a good teaspoon of anhydrous

magnesium sulfate in order to dry them.

Decanter filter off the organic layer and wash the magnesium sulfate residue with a

little more dichloromethane to ensure all the product is extracted.

You should end up with a clear solution of the product.

Distill off the dichloromethane on a hot water bath preferably using a vacuum.

Here's our still warm oily crude product.

It's discolored but is fairly pure.

From this run we got 15.9 grams of product which is a 68% yield from nitratoluene.

This can be distilled again to give pure colorless toluid.

Toluidines are useful as a synthetic building block for many compounds from dyes to pharmaceuticals.