The other characteristic bands of DET are: the aromatic C H
stretching vibration at
∼2990 cm−1; the ring C C stretching vibration
at
∼1500 cm−1; the CH out-of-plan vibration at 730 cm−1; the
band at 3420 cm−1 attributed to overtones of carbonyl group [27].
The product purity was determined through 1H NMR and 13C
NMR, as shown in Figs. 7 and 8, respectively. Three signals were
identified in 1H NMR and were attributed to the structure, also
shown in Fig. 7. The aromatic ring hydrogen atoms identified as
number 1, presented chemical shift at 8.1 ppm. The hydrogens
from ethyl and methyl groups, numbered as 2 and 3, presented the
chemical shift at 4.3 and at 1.39 ppm, respectively. From 13C
NMR spectrum six signals can be observed, the signal that occurs
at 30 ppm belongs to carbons of acetone (used as solvent). The
other five signals were attributed to the structure also shown in
Fig. 8. The aromatic ring carbons, identified as number 1, presented
chemical shift at 130 ppm, and those identified as number 2 presented
the signal at 135 ppm. The carbonyl carbon identified as
number 3 showed signal at 166 ppm. The carbons from ethylene
and methyl groups, numbered as 4 and 5 presented signal at
62 and at 14 ppm, respectively. Since the spectra presented only
chemical shifts related to DET, it is reasonable to infer that impurities,
oligomers and non-reacted PET are not present [22]. The large
amounts of high purity organic products obtained can be explained
by the fact that industrial waste, and not domestic waste, is being
used in this study.