preview

13c Nmr Spectrum

Satisfactory Essays
Analyzing the 13C NMR spectrum of the unknown sample #46, seven distinct signals were studied shown in table (2). Signal 1 had an observed peak value of 21.225 ppm and a calculated peak value11 of 20.8 ppm. Comparing with the literature ppm value5 range 5-30 ppm, signal 1 corresponds with CH3-C=O group. This signal was the second to the most upfield and shielded in the 13C NMR spectrum comparing with signal 7 because of the carbon high electron density. However, it was more downfield than signal 7 due to the presence of the oxygen in the group. Signal 2 had an observed peak value of 171.629 ppm and a calculated peak value10 of 171.0 ppm. Comparing with the literature value5 range 165-180 ppm, signal 2 corresponds with an ester group. Signal 2 is the most downfield and deshielded because the carbonyl group is in between two electronegative oxygens, therefore it could be concluded that there was an ester in the given compound.…show more content…
Comparing with the literature value5 range between 45-65 ppm, signal 3 corresponds with O-CH2 group. Signal 3 was downfield and deshielded comparing with signals 4,5,6, and 7 because it was directly bonded to the oxygen electronegative atom. It can be concluded that signal 3 is a CH2 group connected to the ester group. According to the13C NMR spectrum, signals 4, 5, and 6 were very similar and the three of them were upfield and shielded because of the weak magnetic field applied around them. Signal 4, 5, and 6 had an observed ppm values of 28.253 ppm, 28.248 ppm, and 22.533 ppm respectively and a calculated ppm values10 of 28.5 ppm, 28.3 ppm and 22.4 ppm respectively. Comparing with the literature ppm value5 range 13-35 ppm, signal 4, 5 and 6 corresponds with R-CH2-R group. It can be concluded that signals 4, 5 and 6 are part of CH2 groups. Lastly, signal 7 had an observed ppm value of 14.163 ppm and a calculated ppm value10 of 14.0
Get Access