Olefin polymerization catalyst system
View Patent ↗A catalyst system useful for polymerizing olefins is disclosed. The catalyst system comprises a cocatalyst and a supported transition metal prepared from a halogen-containing Group 4–6 transition metal compound and an organoaluminum-siloxane containing mixture. The latter mixture, which is prepared from an organoaluminum compound and an organomagnesium-siloxane reaction product, incorporates a chelating ligand. The invention includes a method for making the catalyst system and a process for polymerizing olefins using the catalyst system. The process is convenient and avoids expensive catalyst components used in known olefin polymerization processes.
1. A catalyst system which comprises:
a) a cocatalyst selected from the group consisting of trialkylaluminums, dialkylaluminum halides, and alkylaluminum dihalides; and
b) a supported transition metal comprising the reaction product of:
1) a halogen-containing Group 4–6 transition metal compound; and
2) an organoaluminum-siloxane containing mixture comprising the reaction product of:
(a) an organoaluminum compound; and
(b) the reaction product of a polymethylhydrosiloxane and an organic magnesium halide;
wherein at least one of the organoaluminum compound or the organic magnesium halide incorporates a chelating ligand.
2. The catalyst system of claim 1 wherein the organic magnesium halide incorporates the chelating ligand.
3. The catalyst system of claim 2 wherein the chelating ligand is derived from a hydroxyl compound.
4. The catalyst system of claim 3 wherein the hydroxyl compound is selected from the group consisting of hydroxylamines, 2-hydroxypyridines, 8-hydroxyquinolines, hydroxyimines prepared from 2-hydroxyanilines, and hydroxyimines prepared from 2-hydroxybenzaldehydes.
5. The catalyst system of claim 4 wherein the hydroxyl compound is a hydroxylamine.
6. The catalyst system of claim 1 wherein the organoaluminum compound incorporates a chelating ligand.
7. The catalyst system of claim 6 wherein the chelating ligand is derived from a hydroxyl compound.
8. The catalyst system of claim 7 wherein the hydroxyl compound is selected from the group consisting of hydroxylamines, 2-hydroxypyridines, 8-hydroxyquinolines, hydroxyimines prepared from 2-hydroxyanilines, and hydroxyimines prepared from 2-hydroxybenzaldehydes.
9. The catalyst system of claim 8 wherein the hydroxyl compound is a hydroxylamine.
10. A method for making a catalyst system, comprising:
(a) reacting a polymethylhydrosiloxane with an organic magnesium halide to produce an organomagnesium siloxane;
(b) reacting the organomagnesium siloxane with an organoaluminum compound to produce an organoaluminum-siloxane containing mixture;
(c) reacting the organoaluminum-siloxane containing mixture with a halogen-containing Group 4–6 transition metal compound to produce a supported transition metal; and
(d) combining the supported transition metal with a cocatalyst selected from the group consisting of trialkylaluminums, dialkylaluminum halides, and alkylaluminum dihalides;
wherein at least one of the organic magnesium halide or the organoaluminum compound incorporates a chelating ligand.
11. A process comprising polymerizing an olefin using the catalyst system of claim 1 .
12. The process of claim 11 wherein the olefin is selected from the group consisting of ethylene, propylene, 1-butene, 1-hexene, 1-octene, and mixtures thereof.
13. A slurry polymerization process of claim 11 .