Nitrophenol Lab Report

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Four different were gathered from the IR spectroscopy to identify the nitrophenol. The first peak observed was a weak and broad at 3314.75 cm-1, which was corresponded to an alcohol group; therefore this peak must be corresponded to the O-H stretch of the phenol with a literature value that ranges from 3550-3500 cm-1 (Figure 5). The variance between the observed value, and the expected value can be due to the MHz of the IR spectrometer used. The second peak observed was a weak-medium, sharp and narrow at 1586.79 cm-1. This peak was in agreement with the aromatic C=C stretching of a phenol with a literature value that ranges from 1600-1430 cm-1 (Figure 5). The third peak observed was a medium, sharp and narrow at 1487.85 cm-1, coming from a stretch in the nitro …show more content…
After observing the first spectrum, another spectrum was obtained and analyzed. Since para and ortho have similar structures but only different positions, the stretches were the same however the wave numbers were different. The second spectrum had peaks at 3364.69 cm-1, 1615.96 cm-1, 1528.95 cm-1, and 1444.80 cm-1 (Figure 6). When comparing both spectrums it can be seen that the second spectrum has stronger peaks as seen in Figure 6. Typically stronger peaks from the spectrum were corresponded to the ortho isomer, therefore the second spectrum must be the ortho isomer and first spectrum (Figure 5) must have come from the para isomer. This difference in the strength of this peaks was due to the symmetry difference between ortho and para nitrophenols. Peaks in the IR spectra arise from the changes in the dipole moment. When there was more symmetry, there was a reduction in the dipole moment, which weakens the vibrational motions and therefore showed smaller wave numbers in the spectrum.7 As a result of the symmetry in p-nitrophenol, we saw weaker peaks as observed in Figure

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