Polymerization catalysts for producing high molecular weight polymers with low levels of long chain branching

A process for polymerizing olefins, the process comprising:

• contacting an olefin monomer and an optional comonomer with a catalyst composition under polymerization conditions to form a polymer;
• wherein the catalyst composition comprises a contact product of:
• a) at least one ansa-metallocene;
• and b) at least one activator, wherein:
• a) the at least one ansa-metallocene comprises a compound having the formula:
• (X1)(X2)(X3)(X4)M1, wherein
• M1 is titanium, zirconium, or hafnium;
• (X1) and (X2) are independently a substituted cyclopentadienyl, a substituted indenyl, or a substituted fluorenyl;
• one substituent on (X1) and (X2) is a bridging group having the formula ER1R2, wherein E is a carbon atom, a silicon atom, a germanium atom, or a tin atom, and E is bonded to both (X1) and (X2), and wherein R1 and R2 are independently an alkyl group or an aryl group, either of which having up to 12 carbon atoms, or hydrogen, wherein at least one of R1 and R2 is an aryl group;
• at least one substituent on (X1) is a substituted or an unsubstituted alkenyl group having up to 20 carbon atoms;
• at least one substituent on (X2) is an aliphatic group, an aromatic group, a cyclic group, a combination of aliphatic and cyclic groups, an oxygen group, a sulfur group, a nitrogen group, a phosphorus group, an arsenic group, a carbon group, a silicon group, or a boron group, any of which having from 1 to 20 carbon atoms;
• or a halide;
• (X3) and (X4) are independently:
• 1) F, Cl, Br, or I;
• 2) a hydrocarbyl group having up to 20 carbon atoms, H, or BH4;
• 3) a hydrocarbyloxide group, a hydrocarbylamino group, or a trihydrocarbylsilyl group, any of which having up to 20 carbon atoms;
• 4) OBRA2 or SO3RA, wherein RA is an alkyl group or an aryl group, any of which having up to 12 carbon atoms;
• wherein at least one of (X3) and (X4) is a hydrocarbyl group having up to 20 carbon atoms, H, or BH4;
• and
• any additional substituent on the substituted cyclopentadienyl, substituted indenyl, substituted fluorenyl, or substituted alkenyl group is independently an aliphatic group, an aromatic group, a cyclic group, a combination of aliphatic and cyclic groups, an oxygen group, a sulfur group, a nitrogen group, a phosphorus group, an arsenic group, a carbon group, a silicon group, or a boron group, any of which having from 1 to 20 carbon atoms;
• a halide;
• or hydrogen;
• and
• b) the at least one activator is selected independently from:
• i) an activator-support selected from a solid oxide treated with an electron-withdrawing anion, a layered mineral, an ion-exchangeable activator-support, or any combination thereof;
• ii) an organoaluminoxane compound;
• iii) an organoboron compound or an organoborate compound;
• or
• iv) any combination thereof.

A process for polymerizing olefins, the process comprising:

• contacting an olefin monomer and an optional comonomer with a catalyst composition under polymerization conditions to form a polymer;
• wherein the catalyst composition comprises a contact product of:
• a) at least one ansa-metallocene;
• b) optionally, at least one organoaluminum compound;
• and c) at least one activator, wherein:
• a) the ansa-metallocene has the formula:
• M2 is Zr or Hf;
• (R5A) and (R5B) are independently a hydrocarbyl group or a trihydrocarbylsilyl group, any of which having up to 20 carbon atoms;
• or hydrogen;
• n is an integer from 0 to 10, inclusive;
• and
• (X3A) and (X4A) are independently:
• 1) F, Cl, Br, or I;
• 2) a hydrocarbyl group having up to 20 carbon atoms, H, or BH4;
• 3) a hydrocarbyloxide group, a hydrocarbylamino group, or a trihydrocarbylsilyl group, any of which having up to 20 carbon atoms;
• or 4) OBRA2 or SO3RA, wherein RA is an alkyl group or an aryl group, any of which having up to 12 carbon atoms;
• b) the at least one organoaluminum compound comprises a compound having the formula:
• Al(X5)n(X6)3−n,
• wherein (X5) is a hydrocarbyl having from 1 to 20 carbon atoms;
• (X6) is an alkoxide or an aryloxide, any of which having from 1 to 20 carbon atoms, halide, or hydride;
• and n is a number from 1 to 3, inclusive;
• and
• c) the at least one activator is selected independently from:
• i) an activator-support selected from a solid oxide treated with an electron-withdrawing anion, a layered mineral, and an ion-exchangeable activator-support, or any combination thereof;
• ii) an organoaluminoxane compound;
• iii) an organoboron compound or an organoborate compound;
• or
• iv) any combination thereof,
• wherein the at least one organoaluminum compound is optional when:
• 1) at least one of (X3A) and (X4A) is a hydrocarbyl group having up to 20 carbon atoms, H, or BH4;
• 2) the at least one activator comprises an organoaluminoxane compound;
• or 3) both conditions 1 and 2 are present.