Allow the mixture to cool for a few minutes then filter it, using either gravity or vacuum filtration. (We shall be using vacuum filtration.) Wash the residue in the funnel once with a little water and collect all the filtrate. 4. Pour all the filtrate and washings into a 250cm3 volumetric flask.
Experiment 1: Extraction of Caffeine from Tea The primary objective of the experiment is to separate the caffeine from tea leaves. The mixture of tea and the calcium carbonate is separated from tea leaves by vacuum filtration. The solvent used in extraction of caffeine is dichloromethane. Anhydrous magnesium sulfate is added to the dichloromethane solution to dehydrate the mixture. The dichloromethane is then separated from the mixture in the rotary evaporator.
The beaker was then moved to a stir plate with a stir bar and held in place by a ring stand. A funnel attached to an aspirator hose was fixed above to serve as a fume hood. With the aspirator and stir plate both on, 4.79 mL of 6 M HNO3 was added slowly to the beaker until the copper dissolved and the solution turned a light blue color. The hood could now be removed and 10.02 mL of distilled water was added to the solution. While stirring, 6 M NaOH was added drop-wise until the solution became basic, turning red litmus paper blue.
After the effervescence, (15mL) of concentrated HCl was added drop wise to the solution. The mixture was then heated for 15 minutes in a boiling water bath. In two separate small beakers (20mL) of distilled water was placed in one and (20mL) of 6M HCl in the other. Both beakers were placed into an ice bath. After heating, the mixture was cooled to room temperature and filtered by vacuum filtration into a fritted funnel to yield a purple product.
Using another 125-mL flask, 60-mL of 0.3622 M potassium hydroxide in ethanol was deposited. Both flasks were clamped in a temperature-controlled bath regulated at 50.0˚C. The solutions were then set in the temperature bath for ten minutes to equilibrate. An empty 250-mL Erlenmeyer flask was also clamped in the same water bath. In another flask 50-mL of ice water was deposited with three-drop phenolphthalein.
Tannins, which are organic compounds that can bind to alkaloids such as caffeine, are going to be taken out of the tea water using sodium carbonate. The sodium carbonate is a base, which will convert the acidic tannins into sodium salts that are highly soluble in water. Isolating the caffeine will continue once methylene chloride is added to the remaining tea solution, which increases the solubility of the caffeine. Methylene chloride can be evaporated quickly leaving the caffeine to be purified by sublimation. Materials and Methods: The tea solution was obtained when a tea bag was placed in boiling water and its liquid mix was carefully squeezed into a beaker; and eventually placed into a test tube.
Isolation of Caffeine from Teabags by: Ma. Jessa Princess T. Romero John Jezreel Pardinas Submitted to: Mrs. Georgina Diopenes Abstract In this experiment, Caffeine was isolated from Tea, using hot water, sodium carbonate, dichloromethane, and was then purified using sublimation. The crude weight of caffeine was 0.048 grams. The experimental melting point in the 1st trial was 210 0C – 218 0C, in the 2nd trial was 212 0C – 220 0C. Introduction Caffeine is a molecule that is similar to the purine base xanthine.
Gravimetric Determination of Sulfate Purpose The purpose of this lab is to determine the percentage of sulfate in the hydrate by precipitating the sulfate as barium sulfate. Materials Filler paper Sodium sulfate Graduated cylinder Bunsen burner Watch glass Beakers (250 mL, 400 mL) Rubber bulb Graduated pipette Beaker tongs Funnel Filter Paper Sodium Sulfate Drying oven Wash bottle Stirring rod Silver nitrate Hydrochloric acid Distilled water Small test tube Procedures First, .4861 grams of sodium sulfate was placed into a clean 400mL beaker. Exactly 200mL of water and 1mL of HCl was added to the same beaker. A watch glass was placed on the beaker and the solution was heated using the Bunsen burner to a gentle boil. The watch glass was removed with the beaker tongs.
Measure and record the mass of the test tube and metal. 5. Place the test tube containing the metal into the beaker of water and continue heating (10 min). Leave the test tube in the boiling water bath while you complete steps 6 and 7. 6.
This solution was added drop wise to the stirred ethanolic solution of benzophenone at room temperature. After all the sodium borohydride being added, the mixture was stirred for a further 10min. Meanwhile, ice water (10ml) was mixed with concentrated hydrochloric acid (1ml) in 50ml beaker. To this the mixture of sodium borohydride and benzophenone was poured slowly into the beaker. The precipitate was collected using suction filtration and washed with 2 x 5ml portions of water.