Abstract: Catalyst components for the polymerization of olefins CH2?CHR wherein R is hydrogen or a hydrocarbon radical having 1-12 carbon atoms, comprising Mg, Ti, Cl and a compound (L) or its derivatives, selected from condensed cyclic structures which are formed by at least an aromatic ring and which are substituted with at least two hydroxy groups, said Cl and Ti atoms being in an amount such as to have a molar ratio ranging from 5 to 50.

Abstract: Catalyst components for the polymerization of olefins CH2?CHR wherein R is hydrogen or a hydrocarbon radical having 1-12 carbon atoms, comprising Mg, Ti, Cl and a compound (L) or its derivatives, selected from condensed cyclic structures which are formed by at least an aromatic ring and which are substituted with at least two hydroxy groups, said Cl and Ti atoms being in an amount such as to have a molar ratio ranging from 5 to 50.

Abstract: A process for the gas-phase polymerization of one or more alpha-olefins in the presence of a polymerization catalyst system, the process comprising: a) contacting in a continuous way a gas comprising one or more of said alpha-olefins with said catalyst system in a gas-phase tubular reactor at a temperature from 30° C. to 130° C. in order to obtain a polymerization degree up to 500 grams per gram of catalyst system; b) feeding in continuous the prepolymer from step a) to a successive gas-phase polymerization reactor; wherein said gas-phase tubular reactor has a length/diameter ratio higher than 100.

Abstract: A process for preparing a broad molecular weight polyethylene carried out in the presence of a catalyst system comprising (i) a solid catalyst component comprising Mg, Ti, halogen, and optionally an internal electron donor compound, and (ii) an Al-alkyl cocatalyst said process comprising at least two step of polymerization (a) and (b), in which: in a first step (a) ethylene is polymerized in the presence of a molecular weight regulator in order to produce a ethylene (co)polymer, and in a further step (b), which is carried out in the presence of an external electron donor compound added to this polymerization step as a fresh reactant, ethylene is copolymerized with an alpha olefin of formula CH2?CHR, in which R is a C1-C20 hydrocarbon group, to produce an ethylene copolymer having a molecular weight higher than that of the copolymer produced in step (b).

Abstract: A process for preparing heterophasic propylene copolymers by polymerizing propylene in the presence of a polymerization catalyst and hydrogen as a molecular weight regulator, the process comprising the following steps: a) polymerizing in gas- or liquid-phase propylene to prepare a crystalline polymer fraction; b) copolymerizing ethylene with propylene and/or 1-butene, and optionally one or more alpha-olefin comonomers C5-C12, in a gas-phase reactor having interconnected polymerization zones, wherein the growing polymer particles flow upward through a first polymerization zone (riser) under fast fluidization or transport conditions, leave said riser and enter a second polymerization zone (downcomer) through which they flow downward under the action of gravity.