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.

Provided are a transition metal compound for an olefin polymerization catalyst, an olefin polymerization catalyst containing the transition metal compound, and a polyolefin prepared using the olefin polymerization catalyst for polymerization thereof, wherein the transition metal compound is represented by Chemical Formula A1 or Chemical Formula B1.

Provided are a transition metal compound for an olefin polymerization catalyst, an olefin polymerization catalyst containing the transition metal compound, and a polyolefin prepared using the olefin polymerization catalyst for polymerization thereof, wherein the transition metal compound is represented by Chemical Formula A1 or Chemical Formula B1.

The present invention generally relates to compositions comprising and methods for forming functionalized carbon-based nanostructures.

The present invention generally relates to compositions comprising and methods for forming functionalized carbon-based nanostructures.

A process for the production of polyolefins comprising: feeding a slurry comprising at least one polymerization catalyst, at least one carrier liquid, first olefin monomer(s) and optionally at least one first comonomer into at least one loop reactor; polymerizing the first olefin monomer(s) and optionally the at least one first comonomer yielding a first polyolefin; withdrawing the first polyolefin from the loop reactor; feeding the first polyolefin to a gas-solids olefin polymerization reactor, wherein the gas-solids olefin polymerization reactor comprises: a top zone; a middle zone, which comprises a top end in direct contact with said top zone and which is located below said top zone, the middle zone having a generally cylindrical shape; and a bottom zone, which is in direct contact with a bottom end of the middle zone and which is located below the middle zone; introducing a fluidization gas stream into the bottom zone of the gas-solids olefin polymerization reactor; polymerizing second olefin monomer(s) and optionally at least one second comonomer in the presence of the polymerization catalyst and the first polyolefin to a second polyolefin in a dense phase formed by particles of said second polyolefin suspended in an upwards flowing stream of the fluidization gas in the middle zone; introducing a jet gas stream through one or more jet gas feeding ports in a jet gas feeding area of the middle zone at the dense phase in the middle zone of the gas-solids olefin polymerization reactor; withdrawing the second polyolefin from the gas-solids olefin polymerization reactor.

A process for the production of polyolefins comprising: feeding a slurry comprising at least one polymerization catalyst, at least one carrier liquid, first olefin monomer(s) and optionally at least one first comonomer into at least one loop reactor; polymerizing the first olefin monomer(s) and optionally the at least one first comonomer yielding a first polyolefin; withdrawing the first polyolefin from the loop reactor; feeding the first polyolefin to a gas-solids olefin polymerization reactor, wherein the gas-solids olefin polymerization reactor comprises: a top zone; a middle zone, which comprises a top end in direct contact with said top zone and which is located below said top zone, the middle zone having a generally cylindrical shape; and a bottom zone, which is in direct contact with a bottom end of the middle zone and which is located below the middle zone; introducing a fluidization gas stream into the bottom zone of the gas-solids olefin polymerization reactor; polymerizing second olefin monomer(s) and optionally at least one second comonomer in the presence of the polymerization catalyst and the first polyolefin to a second polyolefin in a dense phase formed by particles of said second polyolefin suspended in an upwards flowing stream of the fluidization gas in the middle zone; introducing a jet gas stream through one or more jet gas feeding ports in a jet gas feeding area of the middle zone at the dense phase in the middle zone of the gas-solids olefin polymerization reactor; withdrawing the second polyolefin from the gas-solids olefin polymerization reactor.

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.

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.

The invention relates to a method for producing dialkylamido element compounds. In particular, the invention relates to a method for producing dialkylamido element compounds of the type E(NRR′).sub.x, wherein first WAIN is reacted with HNRR′ in order to form M[Al(NRR′).sub.4] and hydrogen, and then the formed M[Al(NRR′).sub.4] is reacted with EX.sub.x in order to form E(NRR′).sub.x and M[AlX.sub.4], wherein M=Li, Na, or K, R=C.sub.nH.sub.2n+1, where n=1 to 20, and independently thereof R′=C.sub.nH.sub.2n+1, where n=1 to 20, E is an element of the groups 3 to 15 of the periodic table of elements, X=F, Cl, Br, or I, and x=2, 3, 4 or 5.