Chemistry Reference
In-Depth Information
Table 11.1 Physical properties of vegetable oils.
(Reprinted from ref. 46 with
permission from Elsevier.)
Vegetable oil
SBO
Property
HOSBO
ESO
Moringa
Appearance
Light
yellow
Pale
yellow
Colorless
Light
yellow
Kinematic viscosity/cSt
a
at 40 1C
32.93
41.34
170.85
27.1
Kinematic viscosity/cSt
a
at 100 1C
8.08
9.02
20.41
7.0
Acid value/mg KOH g
1
(AOCS Ca 5a-40)
b
0.16
0.12
0.09
0.32
Peroxide value/meq
kg
1
(AOCS Cd 8-3)
b
9.76
4.78
0.0
1.65
Iodine value/mg I
2
g
1
(AOCS Cd 1-25)
b
144.8
85.9
9.11
70
Fatty acid composition by GC/%
(AACC 58-18)
c
C16:0
6.0
6.0
70.0
6.65
30.0
d
C18:0
5.5
3.0
6.09
C18:1
22.0
85.0
0.0
73.85
C18:2
66.0
4.0
0.0
0.99
C18:3
0.5
2.0
0.0
0.0
C20:0
0.0
0.0
0.0
3.98
C20:1
0.0
0.0
0.0
1.99
C22:0
0.0
0.0
0.0
5.85
a
ASTM D-445, ASTM, Philadelphia, 2000.
b
Ocial Methods and Recommended Practices of the American Oil Chemists' Society, AOCS, Urbana,
5th edn, 1998.
c
Approved Methods of the American Association of Cereal Chemists, AACC, St. Paul, 10th edn, vol. 2,
2000.
d
Obtained from the epoxidation of C18:1, C18:2 and C18:3.
in a dynamic system. The data indicate that nearly all the unsaturations in the
FA chains have been converted to epoxy groups. These properties will cumu-
latively influence the thermal and oxidative behavior of ESBO.
11.3.2 Chemically Modified SBO
Many nucleophilic reagents are known to add to oxirane rings, resulting in
ring opening. These ring-opening reactions in ESBO could result in
branching at the oxirane carbons (earlier sites of unsaturation in SBO). The
hypothesis is that appropriate branching groups would interfere with the
formation of macrocrystalline structures during low-temperature appli-
cations and would provide enhanced fluidity to vegetable oils. Triacylgly-
cerols that are hydrogenated to eliminate polyunsaturation will solidify at
room temperature due to alignment and stacking of adjacent molecules.
For this reason, it is important that there should be at least one unsaturation
site available for functionalization that will generate two branching points
on the chain. The ester branching groups are quite effective for attaining the
desired molecular spacing. An ester of six-carbon chain length has been
