Chemistry Reference
In-Depth Information
Tab. 4.2
Polymerization of norbornene using multicomponent catalyst systems.
Run
a)
Activity
b)
Nickel
complex
Co-catalyst Activator
Conversion
[%]
M
w
M
w
/M
n
373000
c
1050000
d, e)
1
Ni(dpm)
2
0.22 mM
AlEt
3
2.2 mM
B(C
6
F
5
)
3
2.0 mM
97
5.95
366000
c)
619000
e)
2
-
95
2.40
3
-
B(C
6
F
5
)
3
0.22 mM
48
186000
-
-
4
-
54
206000
-
-
5
-
46
178000
-
-
6
Pd(dpm)
2
0.22 mM
-
B(C
6
F
5
)
3
2.0 mM
95
insoluble
-
-
7
Pd(dpm)
2
0.22 mM
-
B(C
6
F
5
)
3
0.22 mM
11
-
-
-
0
f)
8
-
BF
3
·Et
2
O
2.0 mM
-
-
-
9
-
B(OEt)
3
2.0 mM
0
-
-
-
10
-
B(OC
6
F
5
)
3
2.0 mM
0
-
-
-
11
Ni(dpm)
2
0.22 mM
-
B(C
6
F
5
)
3
·
3H
2
O
0.22 mM
91
352000
418000
2.43
12
-
87
331000
314000
1.73
a)
All runs were carried out in 1,2-dichloroethane for 1 h at room temperature at 0.9 M norbornene
concentration.
b)
g polymer produced (mol Ni h)
-1
.
c)
Likely to be much higher since a puck formed within 1 min of mixing.
d)
Not completely dissolved.
e)
Partially excluded from column.
f)
No high polymer obtained upon addition to methanol [55].
All experiments were conducted at room temperature for 1 h. In run number 1,
the catalyst was a mixture of Ni(dpm)
2
, AlEt
3
, and B(C
6
F
5
)
3
in a 4000 : 1 : 10 : 9 nor-
bornene :Ni : Al : B molar ratio. High conversion (97%) and activity was achieved.
In fact, the activity observed is in all likelihood much higher than the calculated
373.00 g of polymer obtained per mol nickel metal per hour, since the polymeriza-
tion reaction formed a puck within one minute of addition of the catalyst compo-
nents and polymerization conversion was determined only after an hour. The mo-
lecular weight of the polymer obtained is extremely high, but the actual molecular
weight data should be viewed with some skepticism since the sample was not
completely soluble in trichlorobenzene at 135
C and was partially excluded from
the GPC column.
1
H NMR analysis of the polymer obtained from run 1 unambiguously showed
that the polymer is of the addition type since no double bond resonances are ob-
served. Its
13
C NMR spectrum shows that it is exo enchained. The spectrum does
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