Experiment 10 - The extraction of Caffeine from Cola drinks >> Proper Experimental Technique

Experiment 10 - The extraction of Caffeine from Cola drinks

Proper Experimental Technique

A liquid-liquid extraction is most easily performed with a separatory funnel. A separatory funnel is a vessel shaped like an ice cream cone, with a stopper on one end and a stem on the other end. The end with the stem has a stopcock to control the flow of liquid out of the funnel.

A separatory funnel like the one you'll be using in Experiment 10.

Carrying on with our example from the earlier section, here are the key steps for a successful extraction:

• Pour the aqueous solution containing the organic solute into a separatory funnel.
• Add the extracting solvent, here dichloromethane, to the funnel. Gently invert the funnel several times to mechanically mix up the two solvents, allowing the organic solute to migrate from water into dichloromethane.

• Let the funnel sit for a few minutes to allow the solvent phases to separate.
• Open the stopcock and allow the more dense solvent phase to flow out of the funnel.

A more detailed outline of the extraction procedure can be viewed below: