Name: Bader alshammari Date: 09-04-2019 Title and date of experiment: Caffeine Isolation Date: 09-11-2019 Introduction: This experiment was done to isolate caffeine from caffeine pills by crashing the caffeine pills and mixing them 95% Ethanol. Caffeine affects the central nervous system in human. Thus, both feelings of focusing and awaking occur as results of taking caffeine pills. Caffeine does not occur alone in caffeine pills. However, caffeine is mixed with other components (benzoic acid, propylene glycol, stearic acid, and sucrose) to help in tablet formation. So, after the experiment had done and caffeine was isolated from the pills, we should have less mass than the mass we had for the original pill. Procedure: A Caffeine pill was placed on a watch glass and crushed gently with a glass rod. A funnel was then used to assist in the transformation of the sample from the watch glass to the flask. The crushed pill was transferred to a 25 mL Erlenmeyer flask. Then, 4 mL of 95% ethanol was poured into the flask. An extra 1 mL of 95% ethanol was used to wash down any residuals on the watch glass to ensure transferring the entire sample to the flask. The flask was placed into a water bath and the solution was heated to a boiling point of water around 100 Celsius. A crystallizing dish and a heating stir plate were used to aid this step. A Hot vacuum was used to capture all of the insoluble by attaching the vacuum to the tip of the flask. Caffeine must reach a desirable temperature where it is not crystallized. 3 mL of 95% ethanol was heated in a hot water bath in a test tube. The apparatus for vacuum filtration was set up on a 25 mL filtration flask. Then, a filter paper was placed on the top of the flask with no disruption considered to the filter paper. The solution in the flask was transferred to the filtration flask immediately after pouring 1mL of hot ethanol. After all of the steps above, the remaining 2 mL ethanol was used to wash the Erlenmeyer flask of any remaining Crystals to ensure no wastage. The filtrate solution containing Caffeine and other impurities was exposed to a gentle stream of nitrogen while it was heating. Once the solution was concentrated to a volume of 2mL, the solution was allowed to cool down to room temperature to begin crystallizing. Then, the solution was placed in an ice bath to maximize recovery. The caffeine was isolated from the solution by vacuum filtration and washed with a few drops of cold 50% aqueous ethanol. After the isolation, the material was dried by a drying sheet. Results: Item Properties Caffeine tablet weight 0.4436g Filter paper weight 0.016g Filter paper w/ solid weight 0.0312g Isolated caffeine weight 0.0152g Melting point of isolated caffeine 230C-240C Calculation: Mass of Isolated caffeine: 0.0312g – 0.016g = 0.0152g Melting point percentage error: 230C + 240C/2 =235C Percentage error = 235C/230C*100 = 102.17 (100-102.17)/100 = 0.01% Mass recovery = (Actual mass of caffeine recovered/mass of caffeine in tablet*200 mg) (100) 0.0152g/0.4436g (200mg) = 0.017/mg Discussion: As mentioned before the purpose of the experiment was to isolate the caffeine from caffeine pills. As a result, the mass of isolated caffeine was 0.0152g, and it's melting point was 235C. Also, the mass recovery of the isolated caffeine was 0.017/mg. Significantly, the percentage error for the melting point that was obtained was 0.01% which was almost perfect. By comparing the known melting point 230C and the obtained values235C, we found that they were close, and the results found were expected. Some of the crushed caffeine pill was lost during the transformation from Erlenmeyer flask to the filtration flask. Also, a possible source of error occurred during measuring the weight of both the crushed caffeine pill and the isolated caffeine on the scale. Also, the loss of that mass affected the isolated caffeine melting point. All of those sources could affect the mass and melting point of the isolated caffeine, and they are possible in the lab environment with almost 20 students experimenting at the same time. Conclusion: In conclusion, the procedure's steps were followed to extract the caffeine from caffeine pills. The result values obtained were satisfying and very close to the expected values. To obtain better results for future students, a couple of pieces of advice should be followed. First, a student should be careful during all transformations of material from container to another. Second, students should gently measure weights on the scale to ensure to not lose any material. References Caffeine. (2019, April 30). Retrieved from https://medlineplus.gov/caffeine.html
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