The
idea in this experiment is to extract the water soluble materials in the tea leaves into hot
water. [The solubility of caffeine in water is 22 mg/ml at 25 oC, 180 mg/ml at 80 oC, and 670
mg/ml at 100 oC insoluble material.] The hot solution is allowed to cool and the caffeine is
then extracted from the water with dichloromethane (methylene chloride), which is anorganic
solvent that is insoluble in water. Since caffeine is more soluble in dichloromethane (140
mg/ml) than it is in water (22 mg/ml), it readily dissolves in the dichloromethane.