Weigh the flask and determine the weight of crude caffeine. Do not heat the flask after the solvent has evaporated, or you may sublime some of the caffeine. This should be done in a hood and can be accomplished more rapidly if a stream of dry air or nitrogen gas is directed at the surface of the liquid When the solvent is evaporated, the crude caffeine will coat the bottom of the flask. Evaporate the ethyl acetate by heating the flask in a hot water bath (Technique 7, Section 7.10, p. Transfer the dry ethyl acetate solution with a Pasteur pipet to a dry, preweighed 25-ml Erlenmeyer flask, while leaving the drying agent behind. Allow the mixture to stand for 10-15 minutes. If all the sodium sulfate clumps together when the mixture is stirred with a spatula, add some additional drying agent. Add a small amount of granular anhydrous sodium sulfate to dry the organic layer (Technique 12, Section 12.9, p. Pipe CESUR Y COCO COMO COLETUL DUULUU order to avoid transferring any of the aqueous mixture. After adding sodium carbonate, the molecule become soluble in the organic solvent. In the extract, the nitrogen (in the first ring gets protonated making the molecule water soluble.
Identify the functional groups 4) What change do you expect to occur in the structure in the presence of sodium carbonate.
To the organic extract? 3) Draw the structure of caffeine. Identify the functional groups What change de nu Answer all the questions in the handout for the procedure In addition, answer the following questions 1) What is the purpose of the sodium sulfate? 2) Why does the sodium sulphate clump when added to the organic extract? 3) Draw the structure of caffeine. The following results were obtained: Weight of tea in tea bag = 2.0125 g Weight of caffeine crystals obtained = 32.5 mg Melting point of caffeine obtained = 232 ☌ How much caffeine do you expect to be in a tea leaves that was used? (look it up and cite your reference) Using the above information calculate the % recovery of caffeine.
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