with respect to monomer with lowering the monomer concentration, and a linear
relationship of C M /R with 1/C M (Fig. 3).
The series expansion of the exponent in Eq. (4) gives at small times t the
Eq. (6), which describes the acceleration period on the kinetic curve for polymerization without deactivation of catalyst:
R ¼ k p k i C
à C m
2 t
(6)
According to experimental data (Fig. 4) [17], the rate of polymerization at the
acceleration stage of propene polymerization is second order with respect to
monomer concentration, which fits Eq. (6). It was found from the kinetic results
for propene polymerization [17], that the rate constant of initiation is several orders
16
12
8
4
0
8
16
24
32
1/C M , 1/mol
30°
45°
60°
C M / R.10 -1 , min
Fig. 3 Dependence of
specific stationary rate of
propene polymerization on
the monomer concentration
with VCl 3 –Al(i-Bu) 3 in
n-heptane at temperatures
of 30
C, 45
C and 60
C.
The graph plots C M /R against
1/C M , where C M is the
monomer concentration [31]
2
1.5
1
0.5
0
100 200 300 400 500 * 4.9.10 -4
C M , mol/I
R/(C M [VCI 3 ]t), I/min
2 g
Fig. 4 The rate at initial
acceleration period of
propene polymerization as a
function of the monomer
concentration. Catalyst is
VCl 3 –Al(i-Bu) 3 , temperature
60
C [17]
Kinetics of Olefin Polymerization and Active Sites of Heterogeneous Ziegler. . .
105