Chemistry Reference
In-Depth Information
1
H-NMR spectra of ESBO, DiOH-SBO, Ace-SBO, But-SBO, Isobut-SBO, and
Hex-SBO.
(Reproduced from ref. 47 with kind permission from Springer Science
and Business Media from Springer and the AOCS Press.)
Figure 11.2
spectra (Figure 11.2). Peaks in the region 3.5-3.0 ppm (protons attached to
oxygen of group -CHOH) have disappeared completely and new peaks at
4.8-5.4 ppm (protons at the point of substitution -CH-O-CO-R in FA chains)
appeared in all diester products. The presence of
13
C-NMR peaks at
173.1 ppm due to the carbonyl carbon of triacylglycerols, 68.9 and 62 ppm
respectively for the CH and CH
2
carbons of the -CH
2
-CH-CH
2
- glycerol
backbone and the corresponding protons at 5.2-5.3 ppm and 4.1-4.4 ppm in
the
1
H-NMR spectra of all diester products confirm that the glycerol-FA
linkage is intact and did not undergo any hydrolysis.
11.3.2.1 FT-IR Characterization of Diester Products
The FT-IR spectra (Figure 11.1) of all these products have some common
peaks at 2926 and 2855 cm
1
(methylene asymmetric stretching), 1743 cm
1
(triglyceride carbonyl stretching), 1465 cm
1
(CH
2
bending vibration),
1377 cm
1
(CH
3
symmetrical bending vibration), 724 cm
1
(CH
2
rocking
vibration), and additional peaks at 1242, 1160 and 1104 cm
1
due to
stretching vibrations of the C-O group in esters.
23
Formation of the Ace-SBO
product was also confirmed by the increase in peak intensity ratio
