Abstract:
A class of bridged or unbridged metallocene compounds is disclosed, wherein the cyclopentadienyl ligands have two or four adjacent substituents forming one or two alkylenic cycles of from 4 to 8 carbon atoms.These metallocenes are useful as catalyst components for the polymerization of olefins, particularly for the (co)polymerization of ethylene and for the polymerization of propylene.
Abstract:
A process for preparing bis-cyclopentadienyl compounds bridged by a methylene group is reported, said process comprising reacting formaldehyde with a cyclopentadienyl compound in the presence of a base and of a solvent having a dielectric constant (.epsilon.), measured at 25.degree. C., higher than 7. The bridged compounds, obtainable in high yields with this simple single-step process, can be used to prepare ansa-metallocenes, active as catalyst components in the polymerization of olefins.
Abstract:
Fractionable, reactor blend polypropylenes, directly obtainable from the polymerization reaction of propylene, having: (a) content of isotactic pentads (mmmm) comprised between 25 and 85%; (b) ratio M.sub.w,/M.sub.n
Abstract:
Metallocene compounds having the general formula (I): R1 are hydrocarbon groups, R2 are hydrogen or hydrocarbon groups; M is a transition metal of group 3, 4, 5, 6 or to the lanthanide or actinide groups in the Periodic Table; M′ is a transition metal selected from those belonging to group 3 or to the lanthanide or actinide groups in the Periodic Table; X is a monoanionic ligand; p is an integer of from 0 to 3, being equal to the oxidation state of M minus two; q is an integer from 3 to 5; and n is an integer from 1 to 4, when the six-membered rings of formula (Ia) are not perhydrated, and is an integer of from 0 to 4, when the six-membered rings of formula (Ia) are perhydrated as well as in the compound of formula (Ib).
Abstract:
A class of bridged or unbridged metallocene compounds is disclosed, wherein the cyclopentadienyl ligands have two or four adjacent substituents forming one or two alkylenic cycles of from 4 to 8 carbon atoms. These metallocenes are useful as catalyst components for the polymerization of olefins, particularly for the (co)polymerization of ethylene and for the polymerization of propylene.
Abstract:
Fractionable, reactor blend polypropylenes, directly obtainable from the polymerization reaction of propylene, having:(a) content of isotactic pentads (mmmm) comprised between 25 and 85%;(b) ratio M.sub.w /M.sub.n
Abstract:
Indole and indole derivatives are prepared by contacting under mild reaction conditions an N-(2-toly)formidate, N-(3-methyl-2-pyridyl)formimidate, or N-methyldiazyl formimidate with an alkali metal amide.
Abstract:
2,6-dialkoxybenzoic acid is made by direct metalation of 1,3-dialkoxybenzene by potassium. The metalated dialkoxybenzene is carbonated and acidified to form the dialkoxybenzoic acid.