Abstract: An improved solid Ziegler-Natta type catalyst for the (co)polymerisation of ethylene and ?-olefins, particularly in high-temperature processes, such as for example adiabatic solution processes and high-pressure adiabatic processes with elevated productivity, is provided. Said catalyst is obtained by means of an original process comprising dissolving in hydrocarbons, compounds of titanium, magnesium and optionally a metal selected from hafnium and zirconium, and reprecipitating them in two steps in succession, the first of which is chlorination and the second reduction.

Abstract: A precursor for the formation of catalysts for the (co)polymerization of ?-olefins, comprising titanium, magnesium, at least one metal selected from hafnium and zirconium, aluminum and chlorine, obtained with a process comprising treatment with a siloxane compound. Said solid precursor, used in combination with a suitable co-catalyst in high-temperature (co)polymerization processes of ?-olefins, shows an improved productivity, a high incorporation of co-monomers in the copolymerization of ethylene and an increased thermal stability with respect to the systems so far in use.

Abstract: An improved solid Ziegler-Natta type catalyst for the (co)polymerisation of ethylene and ?-olefins, particularly in high-temperature processes, such as for example adiabatic solution processes and high-pressure adiabatic processes with elevated productivity, is provided. Said catalyst is obtained by means of an original process comprising dissolving in hydrocarbons, compounds of titanium, magnesium and optionally a metal selected from hafnium and zirconium, and reprecipitating them in two steps in succession, the first of which is chlorination and the second reduction.

Abstract: Solid catalyst with a high thermal stability for the (co)polymerization of ?-olefins, comprising titanium, magnesium, at least one metal selected from hafnium and zirconium, aluminum and chlorine, wherein at least 60% of the titanium is in oxidation state +3, and, when examined by means of XPS spectroscopy, has an absorption band characteristic of a binding energy ranging from 455 to 458 eV. Said catalyst, used in combination with a suitable co-catalyst in (co)polymerization processes of ?-olefins at a high temperature, shows an improved productivity, a high incorporation of co-monomers in the copolymerization of ethylene and an increased thermal stability with respect to the systems so far in use.

Abstract: Metal alkyl-arene having general formula (I) or (Ia): M (?6-arene)2AlqXrRs (I) M (?6-arene)AlqXrRs (Ia) wherein: —M represents zirconium (Zr), hafnium (Hf), or mixtures thereof, preferably zirconium; —arene represents a benzene, or a benzene 10 substituted with from 1 to 6 linear or branched C1-C6 alkyl groups, or mixtures thereof; —X represents a halogen atom selected from chlorine, bromine, fluorine, iodine, preferably chlorine; —R represents a linear or branched C1-C15 alkyl group; —q is a number ranging from 2 to 6, preferably 3 for a metal alkyl-arene having general formula (I), 2 for a metal alkyl-arene having general formula (Ia); —r is a number ranging from 1 to 20, preferably 9 for a metal alkyl-arene having general formula (I), 6 for a metal alkyl-arene having general formula (Ia); —s is a number ranging from 1 to 6, preferably 2. Said metal alkyl-arene can be advantageously used for the preparation of solid components of catalysts for the (co)polymerization of ?-olefins.

Abstract: A precursor for the formation of catalysts for the (co)polymerization of ?-olefins, comprising titanium, magnesium, at least one metal selected from hafnium and zirconium, aluminum and chlorine, obtained with a process comprising treatment with a siloxane compound. Said solid precursor, used in combination with a suitable co-catalyst in high-temperature (co)polymerization processes of ?-olefins, shows an improved productivity, a high incorporation of co-monomers in the copolymerization of ethylene and an increased thermal stability with respect to the systems so far in use.

Abstract: Metal alkyl-arene having general formula (I) or (Ia): M (?6-arene)2Al1XrRs (I) M (?6-arene)AlqXrRs (Ia) wherein: —M represents zirconium (Zr), hafnium (Hf), or mixtures thereof, preferably zirconium; —arene represents a benzene, or a benzene 10 substituted with from 1 to 6 linear or branched C1-C6 alkyl groups, or mixtures thereof; —X represents a halogen atom selected from chlorine, bromine, fluorine, iodine, preferably chlorine; —R represents a linear or branched C1-C15 alkyl group; —q is a number ranging from 2 to 6, preferably 3 for a metal alkyl-arene having general formula (I), 2 for a metal alkyl-arene having general formula (Ia); —r is a number ranging from 1 to 20, preferably 9 for a metal alkyl-arene having general formula (I), 6 for a metal alkyl-arene having general formula (Ia); —s is a number ranging from 1 to 6, preferably 2. Said metal alkyl-arene can be advantageously used for the preparation of solid components of catalysts for the (co)polymerization of ?-olefins.

Abstract: Solid catalyst with a high thermal stability for the (co)polymerization of ?-olefins, comprising titanium, magnesium, at least one metal selected from hafnium and zirconium, aluminum and chlorine, wherein at least 60% of the titanium is in oxidation state +3, and, when examined by means of XPS spectroscopy, has an absorption band characteristic of a binding energy ranging from 455 to 458 eV. Said catalyst, used in combination with a suitable co-catalyst in (co)polymerization processes of ?-olefins at a high temperature, shows an improved productivity, a high incorporation of co-monomers in the copolymerization of ethylene and an increased thermal stability with respect to the systems so far in use.

Abstract: The present invention relates to a supported catalyst containing titanium, its preparation and it use in the homo-, co-, and ter-polymerization of olefin-unsaturated compounds. The present invention also relates to a catalytic system comprising a supported catalyst based on titanium and a co-catalyst selected from organo-derivatives of aluminum. More specifically, the present invention relates to catalyst supported on silica, obtained by reacting a titanium halocarboxylate and a magnesium halocarboxylate with an aluminum chloroakylderivative, in the presence of a carrier consisting of high porosity silica. The above reaction essentially takes place in the pores of the silica itself.

Abstract: The present invention relates to a supported catalyst containing titanium, its preparation and it use in the homo-, co-, and ter-polymerization of olefin-unsaturated compounds. The present invention also relates to a catalytic system comprising a supported catalyst based on titanium and a co-catalyst selected from organo-derivatives of aluminum. More, specifically, the present invention relates to catalyst supported on silica, obtained by reacting a titanium halocarboxylate and a magnesium halocarboxylate with an aluminum chloroakylderivative, in the presente of a carrier consisting of high porosity silica. The above reaction essentially takes place in the pores of the silica itself.

Abstract: A catalyst for the polymerization of olefins, containing magnesium, chlorine, aluminium and at least one transition metal, in a dispersed or emulsified form within an inert diluent, is obtained by:contacting, in an inert diluent, a magnesium dialkyl and aluminium trichloride, in a molar ratio equal or almost equal to 2/1, at a temperature lower than 105.degree. C. to obtain a catalyst precursor in a suspended form, or at a temperature higher than 105.degree. C. to form a catalyst precursor in the form of a colloidal emulsion, in the diluent used; andcontacting said suspended or emulsified precursor with at least one compound of a transition metal to form a catalyst in the form of a suspension or emulsion respectively.

Abstract: A supported Ziegler-Natta catalyst active in ethylene polymerization and in the copolymerization of ethylene with alpha-olefins consists of:(A) a cocatalyst in the form of an organometallic compound of aluminium, and(B) a solid catalyst component obtained by:(i) impregnating a granular solid support with a solution of a titanium alcoholate and magnesium chloride in a liquid aliphatic hydrocarbon, followed by evaporation of the hydrocarbon solvent;(ii) impregnating the support treated in (i) with a solution of magnesium chloride in a liquid aliphatic ester, followed by evaporation of the ester solvent; and(iii) activating the support treated in (ii) by contact with an alkyl aluminium halide.In a preferred embodiment, measured quantities of a silicon halide are introduced in stage (i) and/or (ii), this considerably improving catalytic activity.

Abstract: A solid catalyst component for the low-pressure polymerization of ethylene and C.sub.3 -C.sub.10 alpha-olefins into very high molecular weight polyolefins is in the form of a spherical granular solid having a surface area of between 20 and 40 m.sup.2 /g, a mean pore radius of between 5,000 and 40,000 .ANG. and a porosity of between 40 and 90 vol %, and is definable by the following formula (in atomic proportions:X (1), Mg (1-8), Al (0.2-0.8), Cl (5-20), (Et+OEt+OR) (1-3);where: X=Hf or Zr; Et=ethyl group; OEt=ethoxy group; and OR=alkoxy group containing from 2 to 8 carbon atoms in the linear or branched alkyl portion.Such a catalyst component is obtained by preparing a solid spherical granular support by spray-drying an ethanolic solution of magnesium chloride, reacting said support with a hafnium or zirconium alkoxide or halogenalkoxide, and finally reacting the thus treated support with an alkyl aluminum chloride.