136
C. Li et al.
lg(−dC Me /dt) = −1.2085 + 1.6547 · lg(C Me )
To sum up, the chemical reaction kinetics of transesterification can be summarized
as follows:
−
dc Me
dt
= K c
1.3
Me
The reaction speed constant K varies with temperature.
(2) Calculating activation energy of reactions
According to the relationship between reaction speed constant and temperature
change shown above, activation energy can be calculated as presented in Table 5.2.
According to the above data, and by taking 1/T as the horizontal axis and lg (K)
as vertical axis, we will get the following graph (Fig. 5.2).
Based on the above graph, the relationship between reactions speed constant K
and temperature is as follows:
log K = −4320.7 ×
1
T
+ 11.767
Its correlation coefficient R = 0.9671.
According to the above equation, the activation energy of transesterification is
Table 5.2 Activation energy
calculation datasheet
Temperature
(K)
1/T (×10 −3 ) Speed
constant (×
10 −2 min −1 )
Lg(K)
(min −1 )
313.15
3.19
1.07
−1.9687
318.15
3.14
1.40
−1.853
323.15
3.09
1.90
−1.7219
328.15
3.05
5.03
−1.2984
333.15
3.00
6.19
−1.2085
Fig. 5.2 Graph describing
the relationship between
lg(K) and l/T
-2
-1.8
-1.6
-1.4
-1.2
-1
0.00295
0.003
0.00305 0.0031 0.00315
lg(K)
1/T