Chemistry Reference
In-Depth Information
13.97, 13.95, 13.91 (terminal methyl groups of triglycerides); 13.68, 13.64,
13.59 (terminal methyl groups of valeroyl substituents).
10.2.4 Synthesis of Milkweed Polyformate Esters
In a typical experiment, milkweed epoxy oil, 215.20 g (0.225 mol) previously
prepared and characterized
3
as above, was placed in a 1.0 L dry RBF con-
taining a magnetic stirrer bar. Into this RBF was added 124.35 g (2.702 mol,
102 mL) formic acid followed by stirring. The reaction mixture was then
heated to gentle reflux and monitored every 40 min by sampling the contents
for progress in the disappearance of the epoxy band at 820-840 cm
1
using
FT-IR spectroscopy. The reflux was allowed to run overnight after which FT-
IR indicated complete disappearance of the oxirane absorption band. The
heat source was then removed and the system allowed to cool to RT after
which the mixture was transferred into a beaker of saturated NaHCO
3
to
neutralize the excess formic acid. The solution was stirred and more
NaHCO
3
added until effervescence ceased. The organic phase was separated
and saved while the aqueous layer was extracted twice with ethyl acetate
(100 mL
2). The combined organic phase was dried over Na
2
SO
4
and con-
centrated under reduced pressure at 56 1C followed by further drying with a
vacuum pump to yield 294.6 g (98%) of the performyl ester of MWO. The
product density was 1.09 g cm
3
(24 1C); viscosity 388.46 cSt (40 1C) and
44.60 cSt (100 1C), i.e., a VI of 172. The second derivative of the FT-IR
spectrum (film on a NaCl disc) n
NaCl
cm
1
: 2958 s (-CH
3
asym stretch), 2927s
(-CH
2
- asym stretch), 2875 s (-CH
3
sym stretch), 2857 vs (-CH
2
- sym
stretch), 1748 s (C
¼
O triglyceride ester), 1727 vs (C
¼
O formyl ester), 1469 m
(-CH
2
- deform.), 1380 m-w (-CH
3
deform), 1170 vs (-CO
2
stretch), 724 w
(-CH
2
- wag).
1
H-NMR (CDCl
3
) d: 8.05-8.2 (s methine H-CO
2
, 10H), 5.18
(methine H-C-O on the glyceride backbone), 4.4-4.0 (-CH
2
O- on the gly-
ceride backbone), 2.3 m, 2.05 s, 1.5 m, 1.3 m, 0.9 t (6.7 Hz, 7.0 Hz);
13
C-
NMR (CDCl
3
) d: 178.83, 171.16 (C
¼
O on the triglyceride backbone); 161.01,
160.43, 160.30, 160.26 (C
¼
O formyl esters); 81.75, 81.67, 81.09, 80.99, 77.90,
77.79, 77.74, 77.39, 77.26, 74.91, 74.85, 74.80, 73.89, 73.29, 73.24 (-HC-O-);
68.87, 68.57, 68.49 (-CH-O- glyceride backbone); 62.07, 61.90, 61.82, 61.67,
61.42 (-CH
2
-O- glyceride backbone), 35.50, 35.42, 34.08, 34.01, 33.83, 31.89,
31.76, 31.52, 30.51, 29.62, 29.55, 29.40, 29.32, 28.89, 28.85, 28.65, 26.03,
25.78, 25.72, 25.10, 25.01, 24.93, 24.83, 24.68, 24.64, 24.56, 22.65, 22.59,
22.46, 22.43, 22.41, 22.35; 20.99, 14.16, 14.08, 14.05, 13.97, 13.95, 13.92
(-CH
3
).
10.2.5 Cold Flow and Stability Measurements
10.2.5.1 Pour Point
Pour Point (PP) was measured following ASTM method D97-96a
9
to an ac-
curacy of
3 1C. The procedure involves placing a test jar with 50 mL of the
