3.1 Characterization of MO and EMO with1H-NMR
1H NMR spectra of OA, MO and its epoxide (EMO) are
shown in Fig. 1 . Esterification of OA leads to the formation of
MO which is supported by the appearance of a signal at 3.63 ppm
(Fig. 1 ) corresponding to methoxy group (-OCH3)
in MO. The same signal was not originally present in the proton NMR
spectra of OA. The signal appearing at 5.3 ppm is due to the presence of
the unsaturation (-CH=CH-) in the hydrocarbon chain of OA as well as MO.
Accordingly, the formation of EMO from MO was confirmed by the
appearance of signal at 2.9 ppm corresponding to the epoxy protons and
disappearance of signal at 5.3 ppm due to the unsaturated protons
(Fig. 1 ).
1H-1H COSY spectrum of epoxy methyl
oleate and coupling pattern also shows the formation of EMO. Methoxy
protons do not show any coupling and appear as a singlet at δ3.57 ppm. Further, Epoxide ring protons shows coupling with the adjacent
protons, therefore, appeared as a multiplet at δ~ 2.81 ppm ( Fig. 1s, supporting information).
Protons α to the carbonyl group shows coupling with protonsβ to carbonyl group and appear as a triplet at δ 2.23-2.19
ppm. Terminal methyl group also shows coupling with adjacent
-CH2- (methylene protons) and found resonating as a
triplet at δ 0.84-0.79 ppm.
All these couplings show confination of epoxy methyl oleate structure
and splitting pattern.
Characterization of methyl oleate by 1H NMR
(400 MHz, CDCl3) δ (ppm) : 5.39 - 5.30 (m, 2H,
-CH =CH -), 3.66 (s, 3H -OCH3 ),
2.32-2.28 (t, 3H -CH2 -CO-), 2.07-1.98 (m, 4H,
-CH2 CH=CHCH2 -),
1.63-1.58 (m, 2H,
-CH2 -CH2-CO-), 1.35- 1.25 (m,
20H, (CH 2)n-), 0.89-0.86 (t,
3H, -CH2-CH 3) as shown in