aspirin-discussion

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 * __Group 1 __ **

The low percent yield (20%) of aspirin can be attributed to incomplete reaction and product loss during the solid transfer steps of the experiment. It is possible that the salicylic acid did not completely react with acetic anhydride during the reaction. A higher percent yield could potentially be obtained by allowing the boiling mixture to react over a longer period of time, or by driving the reaction to completion by removing the aspirin as it formed. Also during the experiment, there were multiple steps that required the transfer of solid substances. It was difficult to transfer all of the aspirin to the filter paper when filtering the aspirin. Also, due to the lightweight, flakey properties of solid aspirin, it was difficult to transfer the solid to a beaker without losing a few flakes.

The melting point was lower than the literature value by about 6 °  C and broadened. This indicates an impurity in the product. The impurity is most likely salicylic acid that was not removed during the recrystallization step.

The IR and HNMR spectra of our aspirin product reasonably match with the standardized plots from the SDBS database. The IR spectra both show the expected O-H and C=O stretch of the carboxylic acid as well as the aromatic C=C stretch. The footprint regions of the spectra match reasonably well also. Both HNMR plots show signal from carboxylic and aromatic hydrogens, however the HNMR plot of our aspirin product shows more splitting than the SDBS standard. This may be due to the salicylic acid impurity. See IR/HNMR plots in the results section for further analysis.

__ **Group 2** __

In this lab, I felt there was many instances in which product could be lost. It was difficult to move the solid from one container to another. Despite the difficulty, I was able to get a 41% yield percent of aspirin. The melting point of my aspirin was higher than the literature value. There are several potential reasons this may have occurred. Some possibilities the may have contributed to the higher melting point are contamination, aspirin not completely dry, and presence of unreacted reagents. I made several attempts to create a KBr pellet from my product. I was not successful, therefore I was not able to obtain an IR spectrum. I did however get a HMNR spectrum (Figure 1) that looks very similar to the spectrum on the SDBS database (Figure 2). There is a weak signal from the hydrogen on the carboxyl group near 10 ppm. The multiplets near 7-8 ppm correspond to the hydrogens on the benzene ring. The singlet at 2.3 ppm is the methyl group that is present in aspirin.