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A. Zhang and C. Li
linoleic acid
+ H 2
- H 2
H 3 C C 7 H 14
C 7 H 14 C
O
OH
H 3 C C 5 H 10
C 9 H 18 C
O
OH
+ H
2
- H
2
H 3 C C 7 H 14
C 7 H 14 C
O
OH
H 3 C C 5 H 10
C 9 H 18 C
O
OH
Trans eighteen enoic acid
CIS eighteen enoic acid
oleic acid
trans-9-octadecenoic acid
H 3 C
C 16 H 32
C
O
OH
+H 2
octadecoic acid
-CO 2
H 3 C
C 15 H 30
CH 3
Fig. 3.5 Linoleic acid deoxidation
various deoxygenation reactions, namely isomerization, hydrogenation, and deoxidation (Fig. 3.5). The reaction conditions are from 300 to 360 °C under a pressure
of 15–17 Pa; isomerization and hydrogenation first occur, followed by decarboxylation. Under inert conditions, hydrogenation generally occurs on hydrogen treated
catalysts, however, since there is no supply of hydrogen, the rate of hydrogenation
will decrease. For the cleavage of unsaturated esters, the products are primarily the
corresponding saturated esters, and some anaerobic organic products. Figure 3.6
shows the catalytic deoxygenation of stearic acid in Pd/C or Pt/C with high selectivity. The main gas products obtained by online and off-line gas analysis are CO and
CO 2 . These reactions may undergo decarbonylation, decarboxylation, hydrogenation, dehydrogenation, isomerization, cyclization, and dimerization during fatty acid
conversion.