Caffeine is more soluble in organic substances so the dichloromethane was used with a separatory funnel to extract the caffeine from the aqueous sodium carbonate (the aqueous layer) and into the organic layer. Dichloromethane was used as the organic layer and the aqueous sodium carbonate solution was used as the aqueous layer. In a liquid-liquid extraction, two layers are needed- an organic layer and an aqueous layer- that are both immiscible in water. A liquid-liquid extraction was then performed to extract the caffeine from the mixture by adding dichloromethane. Because caffeine is water-soluble and is a base, sodium carbonate must be added to the hot water to prevent it from reacting with the acids present and to ensure it remains a base. Sodium carbonate and hot water were added to the tea bags and was let to stand for about 7 minutes in order to bring the caffeine molecules out of the tea bags and into the aqueous solution. In this experiment, a solid-liquid extraction method was used first to extract the caffeine from the tea leaves/tea bags to by dissolving sodium carbonate in hot water and creating an aqueous sodium carbonate solvent. For both solid-liquid and liquid-liquid extraction techniques, solvents should be chosen by their miscibility in water (should be immiscible), they should have relatively low boiling points for faster and easier extraction, and they should be unreactive with the other substances being used in the experiment. Extraction techniques are used to isolate and remove particular compounds form another substance. In this experiment, we aimed to extract caffeine from the tea leaves in the tea bags provided beginning with a solid-liquid extraction method and then a liquid-liquid extraction. It is a basic substance (due to the nitrogen atoms in its structure) and it appears as a white crystalline solid at room temperature. Caffeine is an organic compound that is found in tea leaves and coffee beans.
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