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xx NaHCO3 100% ==M6.67% error x 100%0.5Aspirin Clerror 100% = 3 8.15%Acid-Base Reactions: 1.68% error 3Caffeine MM HCl H Separation of Pain Reliever Components Data: Figure 1: Separation of Caffeine Figure 2: Separation of Aspirin Figure 3: Structure of Phenacetin Table 1: IR Spectrum Peak Results Aspirin Peak 2865.82 cm-1 3113.92 cm-1 1751.51 cm-1 1605.34 cm-1 1662.72 cm-1 3111.70 cm-1 2955.53 cm-1 1692.70 cm-1 1645.92 cm-1 3103.79 cm-1 2951.25 cm-1 1649.31 cm-1 1694.15 cm-1 Functional Group Alcohol sp2 C C=O C=C C=O sp2 C sp3 C C=O C=O sp2 C sp3 C C=O C=O Caffeine Phenacetin Table 2: Data from the Experiment Aspirin Chemical Formula Weight of Flask Weight After Crystallization Weight of Crystals Starting Melting Point End Melting Point Literature Melting Point Percent Error C9H8O4 2 73.177 g 73.692 g 0.210 g 115 C 124 C 135 C 1 8.15% Phenacetin C10H13NO2 3 72.455 72.665 g 0.515 g 110 C 126 C 135 C 1 6.67% Caffeine C8H10N4O2 4 75.984 76.011 g 0.027 g 223 C 234 C 238 C 1 1.68% Unknown ___B___ Percent Error: Aspirin Melting Point: |124-135| 135 Phenacetin Melting Point: |126-135| 135 Caffeine Melting Point: |234-248| 238 Amount of Each Chemical Used: 35 mL chloroform (CHCl2) 25 mL 0.5 M NaHCO3 33.67 mL 3 M HCl 7 g NaHCO3 >1 g anhydrous MgSO4 Discussion: This lab was done in order to separate APC tablets into its different components to establish which components were present. Understanding the differences in solubility of each component in pain relievers will aid in separating each from the mixture. If one solution is soluble in an organic solvent, and others are soluble in water, the components can begin to be separated due to the fact that organic mixtures and water are not soluble. Also, by adding either an acid or a base to some functional groups may cause different separations to occur, such as an acidic carboxylic acid group mixed with a basic sodium bicarbonate mixture. The methods of extraction will be practiced through the use of a separatory funnel. The use of an Infrared Spectroscopy machine will also be examined and used in order to obtain infrared spectroscopies of the desired mixtures to establish which components were in the unknown mixture. Also, the knowledge of acid-base chemistry will be used in order to separate the chemicals present. In this experiment, 25 milliliters of an unknown mixture was obtained to analyze. 27.0 milliliters of 3 M hydrochloric acid was added to the unknown mixture in the separatory funnel. The solution was shook and given time to allow separation of the layers. The lower layer of chloroform and caffeine was extracted into a labeled flask and the rest was emptied into another labeled flask. 7.0 grams of sodium bicarbonate was then added slowly to the caffeine. When the reaction was complete, 10.0 mL of chloroform was added and placed into the separatory funnel. The solution was allowed time to separate and the bottom layer was transferred to a flask labeled Caffeine, discarding the top layer. A small amount of anhydrous magnesium sulfate was added to remove the water. The solution was gravity filtered into a preweighed flask. The other contents of the original separatory funnel were transferred back into the separatory funnel. 25 milliliters of 0.5 M sodium bicarbonate was added to the separatory funnel mixture, shaken, allowed and time to separate. The bottom layer of phenacetin was saved. Anhydrous magnesium sulfate was then added in small amounts to the phenacetin to remove the water and the solution was gravity filtered into a preweighed flask. 6.67 milliliters of 3 M hydrochloric acid was added to the separatory funnel and the bottom layer of aspirin was saved. Anhydrous magnesium sulfate was added and then the solution was gravity filtered into a preweighed, labeled flask.1 After a week, the crystals were used in the infrared spectroscopy by adding a small amount to the machine and printing the spectroscopy to be analyzed. The melting point was also assessed by placing a small amount of each component into a glass capillary tube and inserted into the Meltemp machine. While the temperature steadily increased, the tubes were examined to notice at what temperatures the crystals began and fully melted.1 The boiling points obtained in the Meltemp apparatus seemed to come within only a few degrees Celsius from the actual melting point temperature of all three substances. Yet, Aspirin and Phenacetin have the same boiling point so this is not a reliable indicator as to whether or not Phenacetin is present. Caffeines melting temperature is very far from the other two melting points so caffeine was present in the unknown. The spectroscopies were then examined to determine which substances were present in the unknown. The theoretical infrared spectroscopy for caffeine contains two carbonyl groups along with peaks present around 3000 cm-1 which is the same peaks present in the experimental spectroscopy.1 The almost parallel peaks indicate that the unknown B contained caffeine. The phenacetin theoretical spectroscopy indicates one carbonyl group, while the experimental spectroscopy showed two almost identical peaks to caffeine in the carbonyl region.1 Because the spectroscopies do not match, the unknown was concluded to not contain phenacetin. The theoretical spectroscopy of aspirin showed the presence of an Oxygen-Hydrogen bond and two carbonyl groups, the same as the experimental spectroscopy.1 One problem which became present in this experiment was the top to the separatory funnel. The tops were not fit perfectly to the funnels hole so liquid continuously seeped out slowly when the apparatus was flipped over to release the pressure. Due to this, and the desire to not come into contact with the chloroform solution, some mixture was lost to paper towels. Also, the 7.0 grams of chloroform which were added to the caffeine was added almost entirely before realizing the two were very reactive. Some of the mixture bubbled out of the flask and was lost. Because the infrared spectroscopy of aspirin and caffeine match the theoretical spectroscopy and the experimental melting points almost equal the theoretical values, it can be concluded that unknown B contained two of the possible components, aspirin and caffeine. References 1. Ault, A. Techniques and Experiments for Organic Chemistry; University Science Books: Sausalito, CA, 1998; pp. 106-108, 532, 338, 332. 2. http://antoine.frostburg.edu/chem/senese/101/moles/faq/molecular-weight.shtml (accessed 09/27/10) 3. http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=4754 (accessed 09/27/10) 4. http://www.chemicalformula.org/caffeine (accessed 09/27/10) ... View Full Document

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