Organic Chemistry Caffeine Extraction Lab ( Tea Bags )

A detailed Summary of Organic Chemistry Caffeine Extraction Lab ( Tea Bags )

To demonstrate the isolation of a natural product from a biological source (tea bags) using extraction techniques, and to demonstrate purification by sublimation.

In a 400ml beaker, 15 tea bags were submerged in approximately 125ml of water. This was brought to a boil over a bunsen burner and allowed to boil for about 15 minutes.

The tea bags were removed from the tea infused water and discarded. 15 grams of Na2CO3 was dissolved in the tea water by stirring, and allowed to cool. It was then transferred into a reparatory funnel. 20ml of Methylene chloride was added and this mixture was shaken gently. The two distinct layers were separated using the "water drop" technique and the aqueous layer was mixed and extracted with another 20ml of Methylene chloride. The organic extracts were combined in a conical flask and dried with about 1gram of anhydrous MgSO4. The solution was allowed to stand for about 10 minutes, and swirled occasionally to complete the drying. The Methylene chloride solution was gravity filtered into a small, pre-weighed beaker. The solvent was carefully evaporated to dryness and the beaker containing the crude caffeine was re-weighed to calculate the yield.

-Sublimation is a process whereby a solid evaporates from a warm surface and condenses on a cold surface, again as a solid. Sublimation occurs when the vapor pressure of a solid reaches the applied pressure so that a substance can pass directly from the solid state to the gas phase. On coming in contact with the cold surface, the vapor will condense to a solid (crystals). Sublimation can readily occur at atmospheric pressure.. For substances with lower vapor pressure vacuum sublimation is used. Caffeine has lower vapor pressure and therefore will sublime only at reduced pressure, and around 180 degrees Celsius.

Our text book contains more detailed information about alkaloids. It states that alkaloids are basic nitrogen-containing compounds of plant origin, many of which are physiologically active when administered to humans. Ingestion of coniine, isolated from water hemlock can cause weakness, labored respiration, paralysis, and eventually death. This is the 'poison hemlock' used in the death of Socrates. In small doses, nicotine is an addictive stimulant. In larger doses, it causes depression, nausea, and vomiting. In even larger doses, it is a deadly poison. Solutions of nicotine in water are used as insecticides. Cocaine is a central nervous system stimulant obtained from the leaves of the coca plant.

Some common words found in the essay are:
, tea bags, crude caffeine, vapor pressure, 15 tea bags, lower vapor pressure, methylene chloride, percent recovery, lower vapor, 15 tea, increase solubility polar, decrease solubility water, chloride solution, caffeine easily, 15 minutes, water increase solubility,

Approximate Word count = 1030
Approximate Pages = 4 (250 words per page double spaced)

Category: Science

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