Catalyst composition with halo-malonate internal electron donor and polymer from same
Disclosed herein are procatalyst compositions, catalyst compositions and polymers, i.e., propylene-based polymers, produced therefrom. The present procatalyst compositions contain a halo-malonate and a 2-fluoro-malonate in particular. The present catalyst compositions improve catalyst selectivity, improve catalyst activity, and also improve hydrogen response during polymerization. Propylene-based polymer produced from the present catalyst composition has a melt flow rate greater than 50 g/10 min.
1. A catalyst composition comprising:
a procatalyst composition comprising a magnesium moiety; a titanium moiety; and
an internal electron donor comprising a 2-fluoro-malonate with the structure (II)
wherein R 1 and R 2 are the same or different, and further wherein R 1 is selected from the group consisting of a C 3 -C 20 secondary alkyl group, a C 4 -C 20 tertiary alkyl group, a C 6 -C 20 aryl group, and a C 7 -C 20 alkylaryl group; and
R 2 is selected from the group consisting of a C 1 -C 20 primary alkyl group and a substituted or unsubstituted C 2 -C 20 1-alkenyl group;
a cocatalyst; and
optionally an external electron donor.
2. The catalyst composition of claim 1 wherein the external electron donor is selected from the group consisting of dicyclopentyldimethoxysilane, n-propyltrimethoxysilane and combinations thereof.
3. The procatalyst composition of claim 1 , wherein R 1 is selected from the group consisting of, an isopropyl group, a tert-butyl, a cyclohexyl group, and a cyclopentyl group.
4. The procatalyst composition of claim 1 wherein the internal electron donor comprises diethyl 2-fluoro-2-cyclohexyl-malonate.
5. The procatalyst composition of claim 1 wherein the internal electron donor comprises diethyl 2-fluoro-2-isopropyl-malonate.
6. The procatalyst composition of claim 1 wherein the internal electron donor comprises diethyl 2-cylcopentyl-2-fluoro-malonate.
7. The procatalyst composition of claim 1 wherein the 2-fluoro-malonate is a compounded 2-fluoro-malonate.
8. The procatalyst composition of claim 1 comprising greater than 5 wt % of the 2-fluoro-malonate.
9. The procatalyst composition of claim 1 wherein the internal electron donor is a mixed internal electron donor comprising the 2-fluoro-malonate and an electron donor component.
10. The procatalyst composition of claim 9 wherein the electron donor component is selected from the group consisting of a C 1 -C 20 unsubstituted or substituted hydrocarbyl ester of a C 1 -C 20 unsubstituted or substituted aliphatic or aromatic carboxylic acid.
11. The procatalyst composition of claim 9 wherein the electron donor component is selected from the group consisting of ethyl acetate and bis(benzoyloxy)dimethylsilane.
12. The procatalyst composition of claim 1 comprising the external electron donor and an activity limiting agent.