This invention relates to catalyst systems comprising a catalyst compound having a bridged group 4 metal metallocene (where the bridge preferably contains an (Me.sub.2Si).sub.2 group, an activator, and a support material. In some embodiments, the present disclosure provides for polyolefins and a process for producing a polyolefin composition comprising contacting at least one olefin with a catalyst system.

The invention relates to a process for preparing a boronic anhydride compound of formula (1), wherein, R.sup.1-R.sup.4 are substituents as defined in the disclosure and ‘B’ stands for the element boron. The invention also describes a process of using the boronic anhydride of formula (1), to prepare a biphenyl metallocene complex of formula (4), wherein, R.sup.1 to R.sup.10, are substituents as defined in the disclosure; and wherein ‘M’ is a transition metal element, ‘Q’ is an halide anion, and ‘P’ is the valency of the transition metal element ‘M’ and indicates the number of halide anion present. In addition, the invention further describes a process of purifying the metallocene complex of formula (4) so as to render the overall metallocene complex synthesis process environmentally sustainable as well as cost effective by minimizing waste effluents.

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Novel polyethylene copolymers having a relatively high comonomer partitioning tendency are disclosed as are methods for their preparation. The comonomer partitioning tendency is the tendency for a copolymer to have comonomer in the higher molecular weight chains. Novel metrics for describing the comonomer partitioning tendency are also disclosed.

The present disclosure provides bridged metallocene catalyst compounds including at least two —Si—Si— bridges, catalyst systems including such compounds, and uses thereof. Catalyst compounds of the present disclosure can be hafnium-containing compounds having one or more cyclopentadiene ligand(s) substituted with one or more silyl neopentyl groups and linked with at least two Si—Si-containing bridges. In another class of embodiments, the present disclosure is directed to polymerization processes to produce polyolefin polymers from catalyst systems including one or more olefin polymerization catalysts, at least one activator, and an optional support.

Catalyst systems and methods for making and using the same. A method of methylating a catalyst composition while substantially normalizing the entiomeric distribution is provided. The method includes slurrying the organometallic compound in dimethoxyethane (DME), and adding a solution of RMgBr in DME, wherein R is a methyl group or a benzyl group, and wherein the RMgBr is greater than about 2.3 equivalents relative to the organometallic compound. After the addition of the RMgBr, the slurry is mixed for at least about four hours. An alkylated organometallic is isolated, wherein the methylated species has a meso/rac ratio that is between about 0.9 and about 1.2.

A system and method of producing polyethylene, including: polymerizing ethylene in presence of a catalyst system in a reactor to form polyethylene, wherein the catalyst system includes a first catalyst and a second catalyst; and adjusting reactor conditions and an amount of the second catalyst fed to the reactor to control melt index (MI), density, and melt flow ratio (MFR) of the polyethylene.

This invention relates to a polyethylene composition, and films therefrom, comprising at least 65 wt % ethylene derived units and from 0.1 to 35 wt % of C.sub.3-C.sub.12 olefin comonomer derived units, where the polyethylene composition has: a) an RCI,m of less than 85 kg/mol; b) a Tw.sub.1−Tw.sub.2 value of from −15 to −40° C.; and c) an Mw.sub.1/Mw.sub.2 value of less than 1.5 where the film has a) a heat seal initiation temperature of X ° C. or less at 5 N of force, where X=0.0015×Y(psi)+62.6 (where Y is the average 1% Secant modulus ((MD+TD)/2)) of the film; b) a dart drop impact of 300 g/mil or more; c) an MD Elmendorf tear of 230 g or more; and d) average 1% Secant modulus ((MD+TD)/2) of 20,000 psi or more.

A system and method of producing polyethylene, including: polymerizing ethylene in presence of a catalyst system in a reactor to form polyethylene, wherein the catalyst system includes a first catalyst and a second catalyst; and adjusting reactor conditions and an amount of the second catalyst fed to the reactor to control melt index (MI), density, and melt flow ratio (MFR) of the polyethylene.

The metallocene compound represented by the following general formula (1): ##STR00001##
(the numerals and signs in the general formula (1) are as described in the description).

A polyethylene according to the present disclosure maintains a stable crystal structure at a high temperature and ensures excellent uniformity in chlorine distribution, thereby preparing a chlorinated polyethylene having excellent chlorination productivity and thermal stability by reacting with chlorine, and may also prepare a PVC compound with improved impact strength by including the chlorinated polyethylene.