of glycerol (GL) and a mole of ester are formed. The order is assumed to be united
irrespective of reactions. The reactions steps are in equations from (6.1) to (6.3)
where k 1 À 8 are rate constants.
Triglyceride
TG
ð Þ
þ Alcohol
A
ð Þ
$
k 1
k 2
Diglyceride
DG
ð Þ
þ Ester À 1
E
ð Þ
ð6:1Þ
Diglyceride
DG
ð Þ
þ Alcohol
A
ð Þ
$
k 3
k 4
Monoglyceride
MG
ð
Þ
þ Ester À 2
E
ð Þ
ð6:2Þ
Monoglyceride
MG
ð
Þ
þ Alcohol
A
ð Þ
$
k 5
k 6
Glycerol
GL
ð Þ
þ Ester À 3
E
ð Þ
ð6:3Þ
Triglyceride
TG
ð Þ
þ 3 Alcohol
A
ð Þ
$
k 7
k 8
3 Ester
E
ð Þ
þ Glycerol
GL
ð Þ
ð6:4Þ
Equation (6.4) is the overall reaction of transesterification, obtained by adding
step reactions (6.1) to (6.3). For forward chemical reaction (6.1):
The rate of decomposition of triglyceride is
Àd TG
½ Š=dt ¼ k 1 TG
½ Š A
½ Š
The rate of decomposition of alcohol is
Àd A
½ Š=dt ¼ k 1 TG
½ Š A
½ Š
The rate of formation of diglyceride (DG) is
d DG
½ Š=dt ¼ k 1 TG
½ Š A
½ Š
The rate of formation of ester is
d E
½ Š=dt ¼ k 1 TG
½ Š A
½ Š
For backward chemical reaction (6.1):
The rate of decomposition of diglyceride is
Àd DG
½ Š=dt ¼ k 2 DG
½ Š E
½ Š
The rate of decomposition of ester is
Àd E
½ Š=dt ¼ k 2 DG
½ Š E
½ Š
The rate of formation of triglyceride is
150
S. Sivamani et al.