Extraction Of Caffeine Lab Template printable pdf download

Extraction of Caffeine

Introduction

Caffeine

Caffeine occurs naturally in tea leaves and coffee beans. Cocoa beans, used to produce

chocolate, contain a compound that is nearly identical in structure to caffeine. Caffeine is also

added to many types of soda and energy drinks. Caffeine is a white solid material at room

temperature. It is classified as an alkaloid—a nitrogen-containing basic (as opposed to acidic)

compound that is obtained from plants and has physiological effects in the body. Caffeine is a

stimulant and mildly addictive. Withdrawal symptoms may include headache and irritability.

There is no conclusive evidence that caffeine causes cancer or heart disease. However, animal

studies suggest it may be a weak teratogen (an agent that causes birth defects in an embryo or

fetus), so pregnant women are advised to limit their intake of caffeinated beverages.

Structure of caffeine:

Extraction

Extraction is a technique in which a solvent is used to remove/isolate a compound of interest

from a liquid substance. For example, coffee is a liquid which contains dissolved caffeine. In

this experiment you will extract (remove) caffeine from coffee. The extraction will be carried out

by simply adding a portion of solvent to the coffee. The caffeine is more soluble in the solvent

than in the coffee, so it “moves out of” the coffee and into the solvent. The solvent, now

containing dissolved caffeine, is then separated from the coffee. At this point the caffeine has

been extracted from the coffee because it is now dissolved in the solvent, rather than the coffee.

If the solvent is allowed to evaporate or is removed in some manner, the caffeine will be left

behind as a white powder.

The solvent that is used for an extraction must be immiscible with the other liquid. Immiscible

liquids are two liquids which are not soluble. In other words, when they are mixed together they

separate into two layers. The denser liquid will form the bottom layer. (Conversely, miscible

liquids are soluble in each other.) In the extraction of caffeine, a solvent that is immiscible with

coffee will be added to the coffee. The mixture will be shaken in order to make the solvent and

coffee mix together as much as possible, enabling the caffeine to move out of the coffee and into

the solvent. As soon as shaking is stopped, the two immiscible liquids will separate into two

layers. The mixture is placed into a separatory funnel (which you used during the isolation of

limonene), enabling the easy separation of one layer from the other—the lower, denser layer can

be drained out of the bottom of the separatory funnel, leaving behind the upper layer.

Extraction Of Caffeine Lab Template