This paper describes an experiment performed in a chemistry 145 laboratory class. The experiment is performed over a three-week time and consist of synthesizing, analyzing and purifying aspirin. It is found that, when a catalyst is used and the reaction occurs at a temperature between 30 and 70℃ for 5-40 min then high yields of acetylsalicylic acid are produced.
Introduction Heinrich Dreser and Friedrich Bayer gave acetylsalicylic acid (ASA) the name that is familiarly known as aspirin in 1899. Today, aspirin is not only one of the most consumed drugs in the world, but it is one of the best-known medicine in today’s society. Aspirin is a pain reliever and a fever reducer and when it is ingested it is broken down to salicylic acid in the…show more content… The purity of the synthesized aspirin is analyzed next. It is analyzed by melting point, Thin Layer Chromatography (TLC) and Ultraviolet Visible Spectroscopy (UV-Vis) [1]. The first analysis was melting point and the melting points of pure salicylic acid, pure Acetylsalicylic acid, commercial aspirin, and synthesize aspirin were measured. The solid compounds were packed into separate capillary tubes and there melting point ranges were measured. The melting point range for pure aspirin is 138-140℃ and the salicylic acid has a melting point range of 158-161℃. Next, TLC was used to analyze the four solid compounds. Chromatography is used to separate components of a mixture as stated by their chemical structure. The compounds can be separated by the stationary phase (silica gel) and the mobile phase (the solvent). The compounds are separated by their attraction and their polarity to the solvent. The the retention factor is measured by dividing the distance the compound traveled by the distance the solvent traveled [1]. Lastly, a UV-Vis spectrophotometer is used to measure the absorbance of the synthesized aspirin product. UV-Vis spectrophotometers detect light in the 400-800 nm range. The UV-Vis spectrophotometer uses ultraviolet and visible light to evaluate the chemical structure of a substance. It is also used to measure the absorbance of a compound. In this specific experiment the spectrophotometer is used to determine the relationship between the…show more content… 3 Data Table TLC Results
Lastly, the UV-Vis spectrophotometer was used to determine the absorbance and the relationship of Salicylic Acid Fe+3. Figures 2 and 3 display that concentration of SA Fe+3 and the absorbance reveal a linear relationship.
Figure 2. Calibration Curve of SA Fe+3 Complex
Figure 3. Calibration Curve displaying a linear relationship
Then the catalyst dependence of the aspirin synthesis. It is concluded that when 0.00ml of H2SO4 catalyst is used then, not high yields of acetylsalicylic acid are produced; whereas, using 0.10 to 1.00ml of H2SO4 catalyst, high yields of acetylsalicylic acid are produced. This means that the reaction does not produce high yields of acetylsalicylic acid unless a catalyst is used. Furthermore, the reaction is independent when there is a catalyst and between all the groups there is some variability. Figures 4 and 5 display the findings of these results.
Figure 4. UV-Vis Catalyst Data
Figure 5. UV-Vis Catalyst Data
Next, figures 6 and 7 show the results of the temperature dependence of synthesized aspirin. It is concluded that between the groups, when the reaction occurred between the temperatures of 30-70℃, high yields of acetylsalicylic acid were produced and the reaction if independent. In addition, there was some variability between the
