How do you separate caffeine on soft drinks?

Answer 1

Its much easier to simply buy caffeine-free drinks to begin with.

But, if you already have caffeinated drinks and wish to separate the caffeine, it can be done pretty easily.

If you are trying to isolate the caffeine from the drinks, you can perform an organic chemistry "Base / Acid, Liquid-Liquid extraction."

In a nutshell, it would go like:

1-Iincrease the pH of the soft drink to 11 or 12 (check for caffeine specifically)

2- Add a non-polar solvent and mix thoroughly for several minutes

3- Let the mixture sit for several minutes/hours, it should form two layers

Usually the bottom layer will be the "water" layer, while the upper layer will be the non-polar solvent containing your caffeine. Some non-polar solvents are heavier than water (like chloroform), and will form the bottom layer.

4- Separate the two layers, keep your non-polar layer with the caffeine.

5- Add a dilute strong acid like hydrochloric acid--or even vinegar (acetic acid), to the non-polar layer and shake for several minutes.

6- Let the mixtures stand for several minutes until two layers form again.

7- The caffeine will now be in your aqueous layer (the water layer). Again, this is typically the lower layer. Separate the layers, keep the water layer.

From here, you can do several things, you could:

A) Let the water evaporate, and it should leave caffeine as a goo or crystal substance at the bottom

B) You could again increase the pH in the water layer to 10 or 11. Let sit in your fridge and caffeine base should precipitate (fall out of solution).

Answer 2

One common way to separate caffeine from soft drinks is through a process called liquid-liquid extraction. In this method, a solvent such as dichloromethane is mixed with the soft drink, causing the caffeine to transfer into the solvent. The solvent is then separated and evaporated to leave behind pure caffeine.