Polymerization catalysts for producing high melt index polymers without the use of hydrogen

A process for producing a catalyst composition comprising contacting an ansa-metallocene compound, a chemically-treated solid oxide, and an organoaluminum compound, wherein:

• (a) the ansa-metallocene compound has the structure:
• (i)
• wherein M1 is titanium or zirconium;
• wherein X1 and X2 independently are a halogen, an alkyl group, an alkyl silyl group, an aryl group, an alkenyl group, an alkynyl group, H, OAr, NR2, NAr2, BH4, SO3Ar, SO3CH3, SO3CF3, or OR, wherein R is an alkyl group having from 1 to about 10 carbon atoms;
• wherein R1 is an alkyl group having from 1 to about 20 carbon atoms, an alkyl silyl group, an alkenyl group, an alkynyl group, or a silyl group;
• wherein E1 is carbon or silicon;
• wherein R2 and R3 independently are an alkyl group having from 1 to about 20 carbon atoms, an alkyl silyl group having from 1 to about 20 carbon atoms, an aryl group, an alkenyl group having from 2 to about 20 carbon atoms, an alkynyl group having from 2 to about 20 carbon atoms, a silyl group, or a hydride group;
• or
• (ii)
• wherein M2 is titanium or zirconium;
• wherein X3 and X4 independently are a halogen, an alkyl group, an alkyl silyl group, an aryl group, an alkenyl group, an alkynyl group, H, OAr, NR2, NAr2, BH4, SO3Ar, SO3CH3, SO3CF3, or OR, wherein R is an alkyl group having from 1 to about 10 carbon atoms;
• wherein R4 and R5 independently are an alkyl group having from 1 to about 20 carbon atoms, an alkyl silyl group having from 1 to about 20 carbon atoms, an alkenyl group having from 2 to about 20 carbon atoms, or an alkynyl group having from 2 to about 20 carbon atoms;
• wherein E2 is carbon or silicon;
• wherein R6 and R7 independently are an aryl group, an alkyl group having from 1 to about 20 carbon atoms, an alkenyl group having from 2 to about 20 carbon atoms, or an alkynyl group having from 2 to about 20 carbon atoms;
• and
• (b) the organoaluminum compound is a compound with the formula:
• Al(X5)n(X6)3-n,
• wherein (X5) is a hydrocarbyl having from 1 to about 20 carbon atoms;
• (X6) is an alkoxide or an aryloxide having from 1 to about 20 carbon atoms, halide, or hydride;
• and n is a number from 1 to 3, inclusive.

A process for forming a polymer having a high melt index in the absence of hydrogen, the process comprising contacting a catalyst composition with at least one type of olefin monomer under polymerization conditions, the catalyst composition comprising an ansa-metallocene compound, a chemically-treated solid oxide, and an organoaluminum compound, wherein:

• (a) the ansa-metallocene compound has the structure:
• (i)
• wherein M1 is titanium or zirconium;
• wherein X1 and X2 independently are a halogen, an alkyl group, an alkyl silyl group, an aryl group, an alkenyl group, an alkynyl group, H, OAr, NR2, NAr2, BH4, SO3Ar, SO3CH3, SO3CF3, or OR, wherein R is an alkyl group having from 1 to about 10 carbon atoms;
• wherein R1 is an alkyl group having from 1 to about 20 carbon atoms, an alkyl silyl group, an alkenyl group, an alkynyl group, or a silyl group;
• wherein E1 is carbon or silicon;
• wherein R2 and R3 independently are an alkyl group having from 1 to about 20 carbon atoms, an alkyl silyl group having from 1 to about 20 carbon atoms, an aryl group, an alkenyl group having from 2 to about 20 carbon atoms, an alkynyl group having from 2 to about 20 carbon atoms, a silyl group, or a hydride group;
• or
• (ii)
• wherein M2 is titanium or zirconium;
• wherein X3 and X4 independently are a halogen, an alkyl group, an alkyl silyl group, an aryl group, an alkenyl group, an alkynyl group, H, OAr, NR2, NAr2, BH4, SO3Ar, SO3CH3, SO3CF3, or OR, wherein R is an alkyl group having from 1 to about 10 carbon atoms;
• wherein R4 and R5 independently are an alkyl group having from 1 to about 20 carbon atoms, an alkyl silyl group having from 1 to about 20 carbon atoms, an alkenyl group having from 2 to about 20 carbon atoms, or an alkynyl group having from 2 to about 20 carbon atoms;
• wherein E2 is carbon or silicon;
• wherein R6 and R7 independently are an aryl group, an alkyl group having from 1 to about 20 carbon atoms, an alkenyl group having from 2 to about 20 carbon atoms, or an alkynyl group having from 2 to about 20 carbon atoms;
• (b) the organoaluminum compound is a compound with the formula:
• Al(X5)n(X6)3-n;
• wherein (X5) is a hydrocarbyl having from 1 to about 20 carbon atoms;
• (X6) is an alkoxide or an aryloxide having from 1 to about 20 carbon atoms, halide, or hydride;
• and n is a number from 1 to 3, inclusive.