One of the most common practical in our house technicians are asked about is simple distillation of cherry cola. Distillation is used for a variety of purposes, and one of the most popular practical in a classroom setting is using something as readily available as flavored cola. So let’s explore!
What is simple distillation?
Simple distillation is a process used to separate a liquid from a mixture, and can be used to separate mixtures containing components with significantly different boiling points.
Where is simple distillation used?
One of the most widely used applications of simple distillation is purifying salt water. It can be used on a large scale, in countries with low rainfall and limited supplies of fresh water. Ships and submarines also use this process to obtain fresh water.
It can also be used to purify ethanol into fuel grade alcohol, a biofuel additive up to 15-25% blend in petrol, most widely used in Brazil, the US and some parts of Europe.
How does simple distillation work?
To purify salt water, the mixture of salt and water is placed in a round bottom (distillation) flask, which is sealed at the top, and then connected to a condenser.
The liquid is heated, and the component with the lowest boiling point will start to evaporate, in this case it is the water.
The water vapour enters the condenser, which has a jacket around it and a constant flow of cold water entering at the bottom of the condenser and circulates up the jacket, cooling the water vapour in the condenser itself, and condenses into purified water.
The water then flows out of the bottom of the condenser into the collection vessel, which on a laboratory scale is usually a beaker.
Simple distillation of cherry cola
As an extension to this practical, cherry cola can be used as the liquid, and the ester that is used to produce the flavour and the smell of the cherry can be separated out from the drink.
You will need
QuickFit™ 250ml round bottom flask
QuickFit™ condenser
100ml beaker
Red rubber tubing
Anti-bumping granules
Set up
The set-up is the same as is used for the distillation of salt water.
- Pour a small amount of cherry cola into a round bottom flask and add a spatula full of anti-bumping granules.
- Set the apparatus up as shown below.
- Connect the bottom end of the condenser to a cold water supply, and place the tubing from the top of the condenser into a sink. Turn the water supply on.
- Heat the liquid gently, as the liquid begins the boil, the flavouring, which has the lowest boiling point in the mixture will start to evaporate.
- It will condense back into a liquid as it travels down the condenser, and the liquid will be collected in the beaker or flask.
- Once you have some liquid in the beaker, remove the heat source, and turn the water supply off.
- Carefully take the beaker which contains the distillate (collected liquid), don’t place the beaker too near the nose, but gently waft the scent towards the nose, and the cherry smell should be noted.
- DO NOT DRINK THE COLA OR THE DISTILLATE.
- All pupils should be given relevant safety guidance and equipment, including safety goggles before carrying out any form of simple distillation.
