Abstract: A process for polymerizing ethylene comprising contacting under polymerization condition ethylene and optionally one or more olefins with a catalyst system obtainable by contacting: a bis amido compound of formula (I) wherein Y is Si, Ge and Sn; X is hydrogen, halogen or an hydrocarbon radical; R1, R2, R3, R4, R5 and R6, are hydrocarbon radical; Q is a neutral Lewis base; and m is 0–2; one or more boron activating cocatalysts and one or more aluminum alkyls or alumoxanes.

Abstract: A catalyst system for the polymerization of olefins comprising the product obtained by contacting: (A) a metallocene complex; (B) an organometallic aluminium compound of formula (II): Al[CH2—C(Ar)R4R5]xHy??(II) wherein Ar is a substituted or unsubstituted aryl group having from 6 to 20 carbon atoms; R4 is a linear or branched, saturated or unsaturated, C1–C10 alkyl, C6–C20 aryl, C7–C20 arylalkyl or C7–C20 alkylaryl; R5 is hydrogen or a linear or branched, saturated or unsaturated, C1–C10 alkyl, C6–C20 aryl, C7–C20 arylalkyl or C7–C13 alkylaryl group; x=2 or 3; y=3-x; and water; the molar ratio (B)/(C) being between 1:1 and 100:1. These catalysts show an improved activity with respect to known catalysts, wherein different aluminium compounds are used.

Abstract: A process for polymerizing ethylene comprising contacting under polymerization condition ethylene and optionally one or more olefins with a catalyst system obtainable by contacting: a bis amido compound of formula (I) wherein Y is Si, Ge and Sn; X is hydrogen, halogen or an hydrocarbon radical; R1, R2, R3, R4, R5 and R6, are hydrocarbon radical; Q is a neutral Lewis base; and m is 0-2; one or more boron activating cocatalysts and one or more aluminum alkyls or alumoxanes.

Abstract: A process for preparing propylene polymer comprising contacting, under polymerization conditions, propylene and optionally ethylene, with a catalyst system comprising a bridged metallocene and a suitable activating cocatalyst, said process being characteized by reducing the concentration of hydrogen formed during the polymerization reaction.

Abstract: A process for preparing propylene polymer comprising contacting, under polymerisation conditions, propylene and optionally ethylene, with a catalyst system comprising a bridged metallocene and a suitable activating cocatalyst, said process being characteised by reducing the concentration of hydrogen formed during the polymerization reaction.

Abstract: Catalysts for the polymerization of olefins are disclosed, which comprise the product obtained by contacting: (A) a bridged and/or substituted cyclopentadienyl compound of titanium, zirconium or hafnium; (B) an organometallic aluminium compound of the formula: Al(CH2—CR4R5—CR6R7R8)wR9qHz wherein R4 is a C1-C10 alkyl, alkenyl, or arylalkyl group; R5 is hydrogen or a C1-C10 alkyl, alkenyl, or arylalkyl group; R6 and R7 are C1-C10 alkyl, alkenyl, aryl, arylalkyl or alkylaryl groups; R8 is hydrogen or a C1-C10 alkyl, alkenyl, aryl, arylalkyl or alkylaryl group; R9 is a C1-C10 alkyl, alkenyl, or arylalkyl group, a carbon atom in the compound of formula (II) being optionally replaced by a Si or Ge atom; w is 1-3, z is 0 or 1, q=3−w−z, and (C) water; the molar ratio (B)/(C) being comprised between 1:1 and 100:1. These catalysts show an improved activity with respect to known catalysts, wherein different aluminium compounds are used.

Abstract: Catalysts for the polymerization of olefins are disclosed, comprising the product obtainable by contacting: (A) a bridged and/or substituted cyclopentadienyl compound of Ti, Zr or Hf; (B) one or more organometallic aluminium compounds of formula (II): AlR43−zHz wherein the substituents R4, same or different from each other, are linear or branched, saturated or unsaturated C1-C20 alkyl or alkylaryl radicals, optionally containing Si or Ge atoms, wherein at least one of the substituents R4 is different from a straight alkyl group; z is 0 or 1; and (C) water, the molar ratio between the organometallic aluminium compound and water being comprised between 1:1 and 100:1; said catalyst being obtainable by a process comprising the following steps: (i) contacting component (A) with part of component (B) in the absence of component (C); (ii) contacting part of component (B) with component (C) in the absence of component (A) and successively (iii) contacting the products obtained in steps (i) and (ii).

Abstract: Catalysts for the polymerization of olefins are disclosed, comprising the product obtainable by contacting: (A) a bridged and/or substituted cyclopentadienyl compound of Ti, Zr or Hf; (B) one or more organometallic aluminium compounds of formula (II): AlR 43−z Hz wherein the substituents R4, same or different from each other, are linear or branched, saturated or unsaturated C1-C20 alkyl or alkylaryl radicals, optionally containing Si or Ge atoms, wherein at least one of the substituents R4 is different from a straight alkyl group; z is 0 or 1; and (C) water; the molar ratio between the organometallic aluminium compound and water being comprised between 1:1 and 100:1; said catalyst being obtainable by a process comprising the following steps: (i) contacting component (A) with part of component (B) in the absence of component (C), (ii) contacting part of component (B) with component (C) in the absence of component (A) and successively (iii) contacting the products obtained in steps (i) and (ii).

Abstract: It is disclosed a new catalyst system for the polymerization of olefins comprising the product obtainable by contacting the following components: (A) one or more compounds of a late transition metal belonging to Group 8-11 of the Periodic Table; and (B) the reaction product of water with one or more organometallic aluminum compounds of formula (IV): Al(CH2—CR3R4R5)xR6yHz, wherein R3 is a C1-C20 alkyl, C3-C20 cycloalkyl or C7-C20 alkylaryl radical; R4 is different from a straight alkyl and is a C3-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl or C7-C20 arylalkyl radical; or R3 and R4 form together a C4-C6 ring; R5 is hydrogen or a C1-C20 alkyl, C6-C20 aryl, C7-C20 alkylaryl or arylalkyl radical; R6 is a C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl or C7-C20 arylalkyl radical; x is 1-3; z is 0-1; and y is 3−x−z; the molar ratio between said organometallic aluminum compound and water being comprised between 0.5:1 and 100:1.

Abstract: It is disclosed a new catalyst system, having high catalytic activity in the oligomerization of &agr;-olefins, comprising a bridged bis-amido Group 4 metal compound of formula (I): wherein M is Ti, Zr or Hf; Y is Si, Ge or Sn; X is a hydrogen, halogen or an hydrocarbon radical; R1, R2, R3, R4, R5 and R6 are hydrocarbon radicals, optionally containing Si, Ge, O, S, P, B or N atoms; Q is a neutral Lewis base; and m is 0-2; in association with a boron activating compound, and with one or more branched alkylaluminiums and/or alumoxanes of branched alkylaluminiums; said catalyst system allows oligomers to be obtained in high yields, with a high selectivity towards &agr;-oligomers.

Abstract: It is disclosed a new catalyst system, having high catalytic activity in the oligomerization of &agr;-olefins, comprising a bridged bis-amido Group 4 metal compound of formula (I): 1