The first term of the equation tends to be
reasonably constant. Thus a plot of left hand side against
1/T allows the activation energy to be determined from the
slope ER. The pre-exponential factor A can be determined
with E known from the above equation.
These values of activation energy, pre-exponential factor and
regression coefficients are given in table 4. The regression
coefficients in table 4 inhcate a very poor fit using a single
stage model. However, use of a two stage model improves the
regression coefficients si@cantly.
The data was also used in equation No. 6 and solved for energy
of activation and pre-exponential factor assuming order of
reaction as 0.5, 0.67 and 1.0. The equation was solved by the
modified Coats a Redfern method In general, the R2 values
increased as the order of reaction increased from 0.5 to 1.0.
Consequently the first order equation may be used to represent
the data reasonably well.
The preilminary computations inhcate that none of the single
stage models provide an acceptable correlation of the
experimental data; the multi stage model are reasonably
accurate. This analysis has been carried out on the basis of
existing models assuming solid state decomposition
characterized by equation 1. Tlus pemts a comparison of the
results wth earlier published work on related homas