Extraction I. Introduction Extraction is a process of obtaining something from a mixture of compound using chemical, physical, or mechanical means. The theory of extraction lies in the immiscibility between two phases to separate a salute to other phase. There is to types of extraction in chemistry namely: liquid to liquid extraction (solvent extraction) which further divided into two types (simple and multiple), and solid liquid extraction. Organic chemical reactions result from the mixture of organic and inorganic compounds. Every reaction involves products, by products, and starting materials. Some products can differ significantly from other in the way they distribute themselves between two immiscible liquids. Such differences are useful in any extraction procedure. Tea and coffee have been popular beverages for centuries, primarily because they contain the stimulant caffeine. It stimulates respiration, the heart, and the central nervous system. It can cause nervousness and insomnia and, like many drugs, can be addictive, making it difficult to reduce the daily dose. A regular coffee drinker who consumes just four cups per day can experience headache, insomnia, and even nausea upon with drawl from the drug. On the other hand, it helps people to pay attention and can sharpen moderately complex mental skills as well as prolong the ability to exercise. II. Objective y y III. To compare single and multiple extraction of caffeine from dried tea leaves. To calculate the percentage yield of caffeine for both extraction procedures.

Methodology

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Data and Results 1. A. weight of tea leaves used B. weight of vial + caffeine C. weight of empty vial D. weight of caffeine 700mg 14.00g 13.7g 0.3g

2. Percentage yield: ( Show computations) Mass of the caffeine % by mass = ___________________ x 100% Mass of tea = 0.3g _________________x 100% 0.7g = 42.86g

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Discussion We obtain a 4.4g of sodium carbonate and about 100mL distilled water to an Erlenmeyer flask. After that, we heat the solution in a water bath while stirring it to dissolve Na2CO3, when the Na2CO3 dissolves the water becomes visible. We add the 700mg or 4 tea bags to the said mixture. Then we boil the tea mixture for 10 minutes, the tea mixed in the water with Na2CO3 after 10 minutes of boiling the solution, then we gently squeeze the tea bags to release the rest of the water (by just pressing it against the side of the flask using a glass rod). y y Cool the aqueous solution; continue cooling in an ice bath. Your tea must be cool before coming in contact with dichloromethane. Dichloromethane will irritate your bare skin (always wear gloves when working with Dichloromethane).

We extract the solution two times with 20mL portions of dichloromethane each time in a separatory funnel (note: do not get dichloromethane on your hands. Take your time. Save and combine the dichloromethane extracts after each extraction.) Then we let it stand until the preparation between two layers is clearly visible the organic layer is visible while the aqueous layer was color brown. After that, we drain the organic layer into a clean Erlenmeyer flask and discard the aqueous layer and we combine all the organic layer extracts. The steps of extraction are a) Pour in 20mL of dichloromethane in the solution. c) Keep your fingers on the stopper and carefully shake the separatory funnel. d) Push out the separatory funnel from time to time with the spigot pointing away from you to relieve gas pressure. e) When the contents have been sufficiently shaken, put the separatory funnel back on the ring stand and let the two layers separate out. f) Remove the stopper. g) Drain the bottom layer into a flask. h) Repeat steps a) through g) one more time for the next extraction. We place the organic layer extracts into a funnel with a filter paper, (and add some sufficient drying agent, about 1 teaspoon usually works well) and place the residue into a vial and let it stand for an hour to evaporate, after the evaporation we add the a chemical to know the result is positive, when it the color becomes orange it is positive.

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Conclusion We conclude that the purpose of the sodium carbonate is to ensure that the acidic substance remains water soluble and that the caffeine will be present as the free base and that orange must be the resulting color to know if the result is positive, after doing this experiment we learn/know how to extract the caffeine in the tea. We enjoyed a lot.

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Answers to questions

1. What is the principle involved in extraction? This involved the extraction of caffeine from tea leaves by using dichloromethane in the end. 2. Draw the structures of caffeine, theobromine, theophylline, and the flavonoid and tannin present in tea.

3. Give the role of sodium carbonate in the extraction of caffeine from tea leaves. To ensure that the acidic substances remains water soluble and that the caffeine will be present as the free base, sodium carbonate is added to the extraction medium. 4. Which of the two layers that formed during extraction is the dichloromethane? Explain your answer. The organic layer extract. 5. Based on the results obtained, compare single extraction with multiple extractions. Which is more efficient? Justify your answer. From the data we gathered we have gained 0.3 of caffeine in 0.7g of tea leaves. Comparing it with multiple extractions, single extraction will have lesser % yield than multiple extractions. Thus, multiple extractions are more efficient than single extraction. 6. What is the role of anhydrous sodium sulfate? In order to remove the last trace of water.

References: http://ochemonline.pbworks.com/f/05_caffeine.pdf