Today we're going to create biodiesel.

This involves a chemical reaction between a fatty acid triglyceride and methanol.

Producing the methyl ester of the fatty acid and glycerin as a side product.

To get a useful fuel you need to use a starting oil which contains fatty acids containing 16 carbons or more.

And which are relatively saturated or only contain one double bond.

Palm oil is the best, but rapeseed, canola and sunflower oil also work well.

We're starting with 500 grams of sunflower oil which is around 600 milliliters.

We're going to add 5 mils in volume.

We've poured this into a large one liter beaker.

The other key ingredient we need to use is methanol.

Ethanol can also be used.

We're using 20% of the weight of the oil, which is 100 grams of methanol.

As you can see this is around 130 mils.

Next we'll prepare our catalyst.

Sodium hydroxide can be used, but this has a problem of creation.

By creating water in the reaction, the perfect catalyst is freshly prepared and dry sodium methoxide solution.

So pour the methanol into a 500 mil flask.

And set it up with a reflux condenser running cold water.

Don't try to do this next step without the condenser.

Now measure out 2.2 grams of sodium metal by cutting with a sharp knife.

You can see our sodium metal is now ready.

The sodium here is already reacting rapidly with the moisture in the air.

So work quickly.

Temporarily remove the condenser and add the sodium to the methanol in the flask.

It starts to react very rapidly, producing hydrogen gas, and the mixture will get hot.

Replace the condenser and allow the sodium to react and dissolve.

Within a minute or two the methanol will get hot and start to react.

Allow the mixture to reflux slightly in the flask.

The sodium metal takes between 5 and 10 minutes to dissolve completely.

Just allow the mixture to reflux and wait until it has all reacted.

Nearly there now.

Here's our hot sodium methoxide solution.

A word of warning.

This solution is extremely basic and you want to be very careful not to spill it or get it done yet.

It's not going to do anything to your skin.

Set up the beaker of oil with strong magnetic stirrin and on a hot plate.

Now add the hot sodium methoxide solution to the oil.

Do this slowly so the mixture doesn't splash.

Once it's all added, you will have a cloudy looking mixture like this.

Once it's all added, you will have a cloudy looking mixture like this.

Our reaction will now start to take place in the mixture and you'll slowly see the cloudy looking mixture.

fade and the mixture will become a bit less viscous. Cover the top of the beaker

with plastic film so that methanol vapor doesn't escape. And now gently heat the

mixture so that it is at a temperature of 55 to 60 degrees C for the next 90

minutes. Then switch off the stirrin and allow to separate. You should see a

viscous bottom layer separating out. You can see that the top layer is now a lot

more fluid than the starting oil. The bottom orange layer is a glycerin

produced by the reaction containing some impurities. Pour the mixture into a

separating funnel. It just fits the 500 ml funnel. Allow the bottom layer of

glycerol to separate completely, then remove it into a beaker.

It's pretty viscous and you'll find that if you leave the easter layer for a

while some more will drop out of suspension in the funnel. Allow to

separate as much as you can and then drain off the last bit of glycerin. If

you want to use the glycerin for another purpose then we suggest purifying it

first. Our target however is the fatty acid ester product.

So we'll discard this. We want to create a lab quality product so we'll first wash

the ester with a small amount of water to remove glycerol, methanol, and any

sodium salts present. Add to the separating funnel and give the mixture a

thorough shake. Then leave for some time to separate as much as possible. Separate

off the bottom aqueous layer.

Remove any estaric day by removing any foamy emulsion produced.

Here's our ester product

looking slightly cloudy still. Pour it into a suitable storage bottle. You can

see that the viscosity is now much less than that of the original starting oil.

It's this property which makes the original oil unsuitable as a fuel in a

normal diesel engine whereas the ester works well.

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We'll use about 10 grams of anhydrous calcium chloride to dry the product.

And here's the product.

500 grams of methyl fatty acid ester, otherwise known as biodiesel.

It's still slightly cloudy so it needs to be left to dry a little more.

We don't have an engine which has been tuned properly to test this on.

However we can do a little experiment and find the flash point of the liquid vapor.

Here's 20 mils of the product.

We poured this into our favorite metal shaker bottle.

And heated it on a hot plate, measuring the temperature using a thermometer.

130 degrees C.

Let's see if the vapor will flash.

That's a no.

Okay 152 degrees C.

No again.

We're looking for the point that there's enough vapor to catch fire.

We'll see a flash and hear it when it goes.

170 degrees C.

That sounds like a flash.

Let's try again.

We didn't show you one of the tests.

But the flash point of our product is between 160 and 170 degrees C.

This is about right.

This is far higher than gasoline.

And even a lot higher than regular diesel fuel.

Potentially making biodiesel a bit safer.

That's all for this video.

Thanks for watching.

We'll see you next time.