A modified solid polyalkylaluminoxane is provided, which is capable of providing α-olefin suppressing adhesion of any polymer produced as a by-product onto the reactor wall and the stirrer, and which is capable of providing a highly active olefin oligomerization reaction catalyst. An olefin oligomerization reaction catalyst containing the modified solid polyalkylaluminoxane is also provided. The modified solid polyalkylaluminoxane for olefin oligomerization reactions contains structural units represented by general formula (a) and structural units represented by general formula (b), whose median diameter is equal to or larger than 0.1 μm and equal to or smaller than 50 μm,

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in which R′ in the general formula (a) represents an alkyl group having 1 to 20 carbon atoms, and R″ in the general formula (b) represents a halogenated alkoxy group having 1 to 20 carbon atoms or a halogenated aryloxy group having 6 to 20 carbon atoms.

Disclosed herein are methods for reprocessing polyurethane compositions such as polyurethane foams. The method comprises introducing a polyurethane composition into a compounding device, heating the polyurethane composition to an effective bond-exchange temperature, and compounding the polyurethane composition for an effective bond-exchange time.

The present invention relates to a method for producing a Tebbe complex having high purity and high activity and having excellent storage stability in a high yield, the method including allowing bis(cyclopentadienyl)titanium dichloride and trimethylaluminum to react with each other in the presence of a solvent such that a solubility of the Tebbe complex in 1 g of the solvent at 25° C. is 0.5 mmol/g or less.

The invention provides a molecular transition metal complex selected from Formula 1, as described herein; an ethylene-based polymer; and a process to form the ethylene-based polymer, said process comprising polymerizing ethylene in the presence of at least one molecular transition metal complex selected from Formula 1, as described herein, and wherein either Z.sub.1 or Z.sub.2 is dative covalent (coordinate) to the metal (M).

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A titanium-oxo-chelate catalyst formulation, comprising: (i) at least one compound of the formula (I), wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.9, R.sub.10, R.sub.11 and R.sub.12 independently of each other are for example hydrogen, halogen, C.sub.1-C.sub.20alkyl, C.sub.6-C.sub.14aryl which is unsubstituted or substituted; or R.sub.1, R.sub.2 and R.sub.3 and/or R.sub.4, R.sub.5 and R.sub.6 and/or R.sub.7, R.sub.8 and R.sub.9 and/or R.sub.10, R.sub.11 and R.sub.12 together with the C-atom to which they are attached each form a C.sub.6-C.sub.14aryl group which is unsubstituted or substituted; or R.sub.1 and R.sub.2 and/or R.sub.4 and R.sub.5 and/or R.sub.7 and R.sub.8 and/or R.sub.10 and R.sub.11 together with the C-atom to which they are attached form a 5- to 7-membered carbocyclic ring; at least one chelate ligand compound of the formula (IIa), (IIb) or (IIc), wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are defined as above for formula (I), is suitable as photolatent catalyst formulation for polymerizing compounds, which are capable to crosslink in the presence of a Lewis acid. ##STR00001##

A catalyst system includes a transition metal salt containing a halo group, an acetate group, or a combination thereof, and an organic phosphine ligand. The molar ratio of the organic phosphine ligand to the transition metal salt is greater than 0 and less than or equal to 50.

This invention relates to hexahydrocyclopenta[e]-as-indacen-1-yl and octahydrobenzo[e]-as-indacen-1-yl based catalyst complexes represented by the formula:

T.sub.yLAMX.sub.n-2

wherein: M is a group 3-6 metal; n is the oxidation state of M; A is a substituted or unsubstituted polycyclic arenyl ligand bonded to M wherein the polycyclic ligand contains an indenyl fragment with two partially unsaturated rings annulated to the phenyl ring of the indenyl ligand fragment; L is a substituted or unsubstituted monocyclic or polycyclic arenyl ligand bonded to M, or a substituted or unsubstituted monocyclic or polycyclic heteroarenyl ligand bonded to M, or is represented by the formula JR′.sub.z-y where J is a group 15 or 16 heteroatom bonded to M, R′ is a substituted or unsubstituted hydrocarbyl substituent bonded to J, and z is 1 or 2; T is a bridging group; y is 1 or 0; and each X is independently a univalent anionic ligand, or two Xs are joined and bound to the metal atom to form a metallocycle ring, or two Xs are joined to form a chelating ligand, a diene ligand, or an alkylidene ligand.

A catalyst composition for selectively hydrogenating a conjugated diene polymer in a homogeneous system is provided, wherein the conjugated diene polymer comprises a conjugated diene monomer or a combination of a conjugated diene monomer and a vinyl aromatic monomer. The catalyst composition includes the catalyst components of (a) a titanium compound; (b) an organometallic compound; and (c) an oligomer containing a polyglycol segment. The hydrogenated polymer produced using the catalyst composition and the method thereof is also provided.

Compounds can be used as catalysts, particularly in ring-opening polymerization reactions, including ring-opening co-polymerization (ROCOP) reactions, or in isocyanate trimerization reactions. The compounds have the formula L-M-X.sub.n, where L is a pyridyl-bis(iminophenolate) ligand, M is a metal ion, X is a co-ligand to balance the charge of the compound, and n is an integer from 0 to 7. The compounds can be prepared by base condensation of a pyridyl-diamine compound with an aldehyde or ketone.

Provided is a hydrogenation catalyst solution comprising a solid catalyst precursor and an activator mixed in a solvent solution where propylene or another alpha-olefin or combination thereof is then added to this solution to prevent the formation of solids and stabilize the solution. The hydrogenation catalyst solution can then be combined with a polymerization catalyst such as Ziegler-Natta catalyst in a polymerization reactor so as to remove excess hydrogen from the reactor during a polymerization process. Hydrogen is eliminated by converting a portion of the olefins (propylene and ethylene) present into alkanes (propane and ethane).