Figure 2. Spectrum 1 shows the ¹H-NMR spectra of SA, with the combined resonance from the alcohol group and the water signal at 5.29 ppm, and the resonances that originate from the aromatic hydrogen atoms in the chemical shift region of 6.73-7.95 ppm. Spectrum 2 shows the ¹H-NMR spectra of phosphoric acid catalyst (85% water) with the resonance from water at 5.73 ppm. Spectrum 3 shows the ¹H-NMR spectra of acetic acid anhydride with a resonance at 2.19 ppm from the methyl groups present. Minor impurities at 2.02 and 1.98 ppm and satellite signals from the methyl group are observable in a cut-out spectra of acetic acid anhydride in Supporting Material (figure 4). Spectrum 4 shows the ¹H-NMR spectrum of 99% d-methanol with TMS at 0.00 ppm. The resonance at 3.31 ppm originates from the non-deuterated methyl group and the resonance at 4.83 ppm is appearing from the alcohol group in methanol and water.

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Introducing NMR to Biomedical Laboratory Scientists through a Laboratory Exercise; Synthesis, Structure Determination and Quantization of Aspirin by Employing an ¹H-NMR Bench Top Instrument

Marit Kristin Leiren, Signe Steinkopf

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