摘要:
A process for polymerizing ethylene is disclosed. The process comprises polymerizing ethylene in the presence of a catalyst system which comprises a bridged indenoindolyl transition metal complex on a support material, an alkylalumoxane, a titanium tetralkoxide, and a branched alkyl aluminum compound. The process provides polyethylenes with low density from ethylene alone.
摘要:
A high-temperature solution process for polymerizing ethylene is disclosed. The polymerization is performed in the presence of a preassembled bimetallic Ziegler-Natta catalyst and an aluminum compound. Molecular modeling calculations predict that the bimetallic Ziegler-Natta catalyst will have good activity and improved stability versus traditional Ziegler-Natta catalysts. This makes the catalyst especially suitable for solution polymerization processes, which require a thermally robust catalyst.
摘要:
A process for making polyolefins is disclosed. The process comprises polymerizing an olefin in the presence of an activator, an organometallic complex, and an aluminum phosphate support. The complex comprises a Group 3 to 10 transition metal and an indenoindolyl ligand that is bonded to the transition metal. The use of the aluminum phosphate support in combination with the indenoindolyl complex provides an unexpected boost in catalyst activity when compared with other common supports. When a combination of olefins is used, good comonomer incorporation is obtained.
摘要:
A dual olefin polymerization process is disclosed. The process uses a bridged indenoindolyl ligand-containing Group 4 transition metal complex and an activator. It is carried out in multiple stages or in multiple reactors. The same complex and the same activator are used in all stages or reactors. Different polyolefins are made in different stages or reactors by varying the monomer compositions, hydrogen concentrations, or both. The process of the invention produces polyolefins which have broad molecular weight distributions, composition distributions, or both.
摘要:
A process for polymerizing olefins is disclosed. The process polymerizes an olefin in the presence of a dehydrogenation catalyst and an olefin polymerization catalyst. The dehydrogenation catalyst enables in-situ generation of alkenes from oligomers or solvent. The alkenes are then incorporated into the polyolefin. The polyolefin should have increased long-chain branching and lower density without the use of expensive comonomers.
摘要:
An olefin polymerization catalyst system and method of making it are disclosed. The catalyst system comprises an activator and an organometallic complex. The complex comprises a Group 3 to 10 transition or lanthanide metal, M, and at least one anionic 1,3-diboretanyl ligand that is bonded to M. Molecular modeling results indicate that catalysts from organometallic complexes that incorporate anionic 1,3-diboretanyl ligands will rival the performance of traditional metallocenes.
摘要:
A catalyst system useful for polymerizing olefins is disclosed. The catalyst system comprises an activator and a complex that incorporates a Group 3 to 10 transition metal and at least one chelating dianionic bis(allyl) or bis(benzyl) ligand. The ligands are often easy to make, and they are readily incorporated into transition metal complexes. By modifying the structure of the dianionic ligand, polyolefin makers can control comonomer incorporation, catalyst activity, and polymer properties.
摘要:
Catalyst systems useful for olefin polymerization are disclosed. The catalyst systems include an activator and an organometallic complex. The complex, which incorporates at least one Group 3-10 transition or lanthanide metal, is uniquely prepared from an indenoindolyl dianion or its synthetic equivalent. A diverse array of monomeric, dimeric, polymeric, or zwitterionic complexes are available from the dianion or its equivalent.
摘要:
Disclosed is a method of polymerizing vinyl chloride monomer using a catalyst having the general formula where L is a ligand covalently bonded to the cobalt atom, each D is independently selected from donor ligands, R is hydrogen, hydrocarbon from C1 to C30, or hydrohalocarbon from C1 to C30, and X− is an anion. The catalyst is activated by the addition of an acid.