Ziegler-Natta catalyst for high temperature polymerization
The various embodiments of the invention provide, a magnesium titanium polymerization procatalyst, methods for making and using the same.
1. A procatalyst for polymerization of ethylene and α-olefins, the procatalyst comprising at least 0.2% of a species detectable by EPR having a g value of 1.950 that is associated with a tetrahedral Ti 3+ species.
2. The procatalyst of claim 1 , comprising from about 0.2 to about 1% of a species detectable by EPR having a g value of 1.950 that is associated with a tetrahedral Ti 3+ species.
3. The procatalyst of claim 1 , wherein the procatalyst for polymerization of ethylene and α-olefins comprises a Ti 3+ complex of the formula TiCl 3 *[[R 4 ] a [R 5 O] b AlX 3-c ] d wherein
a is 0 to 1;
b is 0 to 1;
c=a+b;
d is from about 0.33 to about 1.0;
each R 4 and R 5 is independently selected from C 1-8 alkyl radicals;
each X is independently chosen from the halogen radicals;
the Mg/Ti molar ratio is from about 5 to about 10;
and further wherein at least 60% of the total Ti present is in the Ti 3+ oxidation state.
4. The procatalyst of claim 3 , wherein X is Cl.
5. The procatalyst of claim 3 , wherein a is 0 and b is 0.
6. The procatalyst of claim 3 , wherein a is 0 and b is 1.
7. The procatalyst of claim 3 , wherein a is 1 and b is 0.
8. The procatalyst of claim 3 , wherein each R 5 is ethyl.
9. The procatalyst of claim 3 , wherein the Mg/Ti ratio is from about 5 to about 8.
10. The procatalyst of claim 3 , wherein the Ti 3+ complex is TiCl 3 *[OEtAlCl 2 ] d , and the Mg/Ti molar ratio is from about 5 to about 8.
11. The procatalyst of claim 3 , wherein the Ti 3+ complex is TiCl 3 *[ClAlCl 2 ] d , and the Mg/Ti molar ratio is from about 5 to about 8.