Abstract: Process for the preparation of a solid olefin polymerisation catalyst system, comprising an organometallic compound of a transition metal of Group 3 to 10 of the Periodic Table (IUPAC 2007) in the form of solid particles comprising the steps of I) generating an emulsion by dispersing a liquid clathrate in a solvent (S) wherein (i) the solvent (S) constitutes the continuous phase of the emulsion and comprises a nonreactive fluorinated synthetic oil having a viscosity at 20° C.

Abstract: The present invention relates to catalysts component for the polymerization of ethylene and its mixtures with olefins CH2?CHR, wherein R is an alkyl, cycloalkyl or aryl radical having 1-12 carbon atoms, comprising Ti, Mg, halogen, and electron donor belonging to 1,2-diethers as internal electron donor compound. The catalyst of the invention is suitably used in (co)polymerization processes of ethylene to prepare (co)polymers having narrow Molecular Weight Distribution (MWD) and high bulk density.

Abstract: Catalyst component for the polymerization of olefins CH2?CHR in which R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, comprising Mg, Ti, halogen and two electron donor compounds one of which selected those of formula (I) wherein: R2, equal to or different from each other, are hydrogen atoms or C1-C20 hydrocarbon radicals optionally containing heteroatoms belonging to groups 13-17 of the periodic table of the elements or alkoxy groups of formula —OR1, two or more of the R2 groups can be connected together to form a cycle; R1, equal to or different from each other, are C1-C20 hydrocarbon radicals optionally containing heteroatoms belonging to groups 13-17 of the periodic table of the elements, with the proviso that at least one of R2 is —OR1 and the other being selected from succinates of formula (II): wherein the radicals RI and RII, equal to or different from each other, are a C1-C20 linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group, optionally containi

Abstract: Catalyst component for the polymerization of olefins CH2?CHR in which R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, comprising Mg, Ti, halogen and two electron donor compounds one of which selected from alkoxybenzenes and the other being selected from those of formula (II) where RI and RII are the same or different and are hydrogen or linear or branched C1-C18 hydrocarbon groups which can also form one or more cyclic structures; RIII groups, equal or different from each other, are hydrogen or C1-C18 hydrocarbon groups; RIV groups equal or different from each other, have the same meaning of RIII except that they cannot be hydrogen; each of RI to RIV groups can contain heteroatoms selected from halogens, N, O, S and Si.

Abstract: A magnesium halide adduct is provided, comprising at least one compound of the formula MgXY, at least one compound of the formula ROH, methanol, at least one modifying agent chosen from DOE and o-hydroxy benzoates, and optionally water. Also provided herein are a catalyst component comprising the magnesium halide adduct, a catalyst for olefin polymerization comprising the catalyst component; the respective processes for preparing the magnesium halide adduct and the catalyst component; use of the magnesium halide adduct for preparing the catalyst component, use of the catalyst component in a catalyst for olefin polymerization and use of the catalyst in olefin polymerization; and a process of olefin polymerization.

Abstract: A solid catalyst component for olefin polymerization in which the molar ratio of residual alkoxy groups to supported titanium is 0.60 or less is obtained by reacting the following compound (a1) with the following compound (b1) at a hydroxyl group/magnesium molar ratio of 1.0 or more, reacting the reaction mixture with the following compound (c1) at a halogen/magnesium molar ratio of 0.20 or more, reacting the resultant reaction mixture with the following compounds (d1) and (e) at a temperature of 120° C. or higher but 150° C.

Abstract: Catalyst component comprising Mg, Ti, and halogen atoms, and is characterized in that (a) the Ti atoms are present in an amount higher than 4% based on the total weight of the said catalyst component, (b) the amount of Mg and Ti atoms is such that the Mg/Ti molar ratio is higher than 2 and (c) by a X-ray diffraction spectrum, in which, in the range of 2? diffraction angles between 47° and 52°, at least two diffraction lines are present at diffraction angles 2? of 48.3±0.2°, and 50.0±0.2°, the most intense diffraction lines being the one at 2? of 50.0±0.2°, the intensity of the other diffraction line being equal to or lower than the intensity of the most intense diffraction line.

Abstract: A catalyst component for olefin polymerization is disclosed, which comprises a reaction product of the following components: (1) a spheric carrier; (2) a titanium compound; and optionally, (3) an electron donor, wherein the spheric carrier comprises a reaction product of at least the following components: (a) a magnesium halide represented by a general formula of MgX2-nRn, wherein X is independently chloride or bromide, R is a C1-C14 alkyl, a C6-C14 aryl, a C1-C14 alkoxy, or a C6-C14 aryloxy, and n is 0 or 1; (b) an alcohol compound; and (c) an epoxy compound represented by a general formula (I), wherein R2 and R3 are independently hydrogen, a C1-C5 linear or branched alkyl, or a C1-C5 linear or branched haloalkyl.

Abstract: A catalyst component for olefin polymerization is disclosed, which comprises at least one diol ester type electron donor compound (a) and at least one diether type electron donor compound (b) among others, wherein the molar ratio of a to b is 0.55-50. A preparation method of the catalyst component, a catalyst comprising the catalyst component, and an olefin polymerization method using the catalyst which can especially be used for preparation of polypropylenes of low ash contents are also disclosed.

Abstract: The object is to provide a catalyst component for ethylene polymerization which can produce an ethylene polymer of high molecular weight which has substantially only an ethyl branch, and a process for producing the catalyst component for ethylene polymerization which can produce an ethylene polymer of high molecular weight which has substantially only an ethyl branch. A catalyst component for polymerization of ethylene obtained by contacting the following components (A), (B), (C) and (D): component (A): a meso-metallocene compound, component (B): a compound which ionizes a metallocene compound to form an ionic complex, component (C): an organoaluminum compound, and component (D): an electron donating compound, and a process for producing the ethylene polymer by polymerizing ethylene in the presence of the above catalyst component for ethylene polymerization.

Abstract: Disclosed herein are catalyst compositions and polymers, i.e., propylene-based polymers, produced therefrom. The present catalyst compositions include an internal electron donor with an alkoxypropyl ester. The present catalyst compositions improve catalyst selectivity. Propylene-based polymer produced from the present catalyst composition has a melt flow rate greater than 4 g/10 min.

Abstract: Disclosed herein are processes for preparing procatalyst compositions with an internal electron donor containing greater than 4.5 wt % of a compounded alkoxyalkyl ester. Also disclosed are catalyst compositions containing the procatalyst composition and polymers, i.e., propylene-based polymers, produced therefrom. The present procatalyst compositions improve catalyst selectivity, catalyst activity, procatalyst morphology and polymer particle morphology, and improve hydrogen response during olefin polymerization.

Abstract: Disclosed herein are catalyst compositions and polymers, i.e., propylene-based polymers, produced therefrom. The present catalyst compositions include an internal electron donor with a compounded alkoxyalkyl ester and optionally a mixed external electron donor. The present catalyst compositions improve catalyst selectivity, improve catalyst activity, and/or improve hydrogen response. Propylene-based polymer produced from the present catalyst composition has a melt flow rate greater than 10 g/10 min.

Abstract: Disclosed herein are catalyst compositions and polymers, i.e., propylene-based polymers, produced therefrom. The present catalyst compositions contain an internal electron donor of an alkoxyalkyl 2-propenoate and optionally a mixed external electron donor. The present catalyst compositions improve catalyst selectivity and polymer stiffness. Polypropylene homopolymer produced from the present catalyst composition has a xylene solubles content less than 4 wt % and a TMF greater than 172.0° C.

Abstract: Disclosed herein are procatalyst compositions, catalyst compositions and polymers, i.e., propylene-based polymers, produced therefrom. The present procatalyst compositions contain a halo-malonate and a 2-fluoro-malonate in particular. The present catalyst compositions improve catalyst selectivity, improve catalyst activity, and also improve hydrogen response during polymerization. Propylene-based polymer produced from the present catalyst composition has a melt flow rate greater than 50 g/10 min.

Abstract: This invention relates to a supported nonmetallocene catalyst for olefin polymerization, which is produced by directly reacting a nonmetallocene ligand with a catalytically active metallic compound on a carrier through an in-situ supporting process. The process according to this invention is simple and feasible, and it is easy to adjust the load of the nonmetallocene ligand on the porous carrier. The supported nonmetallocene catalyst according to this invention can be used for olefin homopolymerization/copolymerization, even in combination with a comparatively less amount of the co-catalyst, to achieve a comparatively high polymerization activity. Further, the polymer product obtained therewith boasts desirable polymer morphology and a high bulk density.

Abstract: A catalyst system containing (a) a solid catalyst component containing a titanium halide, a magnesium halide, a first internal electron donor compound, and a second internal electron donor compound, (b) an organoaluminum compound, and (c) an external electron donor compound is disclosed. The first internal electron donor compound contains at least one ether group and at least one ketone group. The second internal electron donor compound is a 1,8-naphthyl diester compound. Methods of polymerizing or copolymerizing alpha-olefins using the catalyst system also are disclosed.

Abstract: Disclosed are catalyst compositions for isoprene polymerization formed from components comprising (A) at least one titanium halide; (B) at least one organic aluminum compound comprising at least one alkyl aluminum of formula AlR3, wherein each of the three Rs is independently chosen from linear and branched C1-6 alkyl groups; and (C) at least one electron donor comprising at least one polyether compound of formula (I) and/or at least one tetrahydro-furfuryl ether compound of formula (II). Also disclosed are processes for preparation of the catalyst compositions and processes using the catalyst compositions for isoprene polymerization.

Abstract: Random propylene/ethylene copolymers are provided characterized by Ethylene content in the range of 4.5-7% wt; Mw/Mn (via GPC) in the range 3.5-5.5; Mz/Mw (via GPC) lower than 4; absence of 2-1 regioinversion, and Melting Temperature (Tm) (non-nucleated grade) lower than 143° C. The said copolymers show an excellent balance of impact and optical properties which is retained even after visbreaking.

Abstract: A catalyst component for the polymerization of olefins comprises Mg, Ti, halogen, and an alpha-omega-diether represented by the general formula: (RO)—(CR1R2)n—(OR), wherein the number of n is from 5 to 10, R is an alkyl, cycloalkyl or aryl radical containing 1 to 12 carbons, and R1 and R2 are independently from each other hydrogen, an alkyl, cycloalkyl or aryl radical containing 1 to 12 carbons. The catalysts prepared with such component provide a high mileage for the production of polyolefins with a high bulk density of the polymer produced in gas-phase polymerization process or in slurry polymerization process. Such catalyst produces narrower MWD PE, if compared with other catalyst systems.

Abstract: The present invention relates to catalyst systems containing solid catalyst components comprising titanium, magnesium, halogen and an internal electron donor compound having at least one ether group and at least one ketone group; organoaluminum compounds and alkyl benzoate derivatives as external electron donors. The present invention also relates to methods of making the catalyst systems, and methods of polymerizing or copolymerizing alpha-olefins using the catalyst systems.

Abstract: A catalyst composition for the polymerization of propylene comprising one or more Ziegler-Natta procatalyst compositions comprising one or more transition metal compounds and one or more esters of aromatic dicarboxylic acid internal electron donors; one or more aluminum containing cocatalysts; a selectivity control agent (SCA) comprising at least one silicon containing compound containing at least one C1-10 alkoxy group bonded to a silicon atom, and one or more activity limiting agent (ALA) compounds comprising one or more aliphatic or cycloaliphatic carboxylic acids; alkyl-, cycloalkyl- or alkyl(poly)(oxyalkyl)-(poly)ester derivatives thereof; or inertly substituted derivatives of the foregoing.

Abstract: The present disclosure provides a Ziegler-Natta catalyst composition comprising a procatalyst, a cocatalyst and a mixed external electron donor comprising a first selectivity control agent, a second selectivity control agent and an activity limiting agent. A polymerization process incorporating the present catalyst composition produces a high-stiffness propylene-based polymer with a melt flow rate greater than about 50 g/10 min. The polymerization process occurs in a single reactor, utilizing standard hydrogen concentration with no visbreaking.

Abstract: A catalyst composition for the polymerization of propylene is provided. The catalyst composition includes one or more Ziegler-Natta procatalyst compositions having one or more transition metal compounds and one or more esters of aromatic dicarboxylic acid internal electron donors, one or more aluminum containing cocatalysts and a selectivity control agent (SCA). The SCA is a mixture of an activity limiting agent and a silane composition. The catalyst composition has a molar ratio of aluminum to total SCA from 0.5:1 to 4:1. This aluminum/SCA ratio improves polymerization productivity and the polymer production rate. The catalyst composition is self-extinguishing.

Abstract: A hydrogenation catalyst composition for hydrogenating a polymer of conjugated diene is provided. The polymer of conjugated diene is a homopolymer of conjugated diene or a copolymer of conjugated diene and vinyl aromatics. The hydrogenation catalyst composition includes: (a) a titanium compound, (b) a compound of formula (II), where R5 is C1˜C12 alkyl, alkenyl, amine, ether, ketone or ester groups, R3 and R6 are C1˜C12 alkyl or alkenyl groups, R4 and R7 are C1˜C12 alkyl, alkenyl, amine, ether, ketone or ester groups, n and m are integrals, 1?n?3, 1?m?3, and (c) alkyl aluminum.

Abstract: A catalyst component for ethylene polymerization, comprising an organic silicon compound of the formula (I), below wherein R1 is chosen from C3-C20 aliphatic hydrocarbyl groups, and is substituted with at least one substituent chosen from halogens, C1-C6 acyloxy groups, epoxy, amino, C1-C6 alkylamino groups, di(C1-C6 alkyl)amino groups, C1-C6 alkoxy groups, and oxo group; R2, R3 and R4, which may be the same or different, are each chosen from C1-C10 aliphatic hydrocarbyl, C3-C10 alicyclic hydrocarbyl, C6-C10 aryl, C7-C10 aralkyl, and C7-C10 alkaryl groups. A process for preparing the catalyst component and an active catalyst comprising the catalyst component and useful in polymerization, such as ethylene polymerization.

Abstract: The present disclosure provides a Ziegler-Natta catalyst composition comprising a procatalyst, a cocatalyst and a mixed external electron donor comprising a first selectivity control agent, a second selectivity control agent, and an activity limiting agent. A polymerization process incorporating the present catalyst composition produces a high-stiffness propylene-based polymer with a melt flow rate greater than about 50 g/10 min. The polymerization process occurs in a single reactor, utilizing standard hydrogen concentration with no visbreaking.

Abstract: A catalyst component for olefin polymerization comprising an ?-cyanosuccinate compound as an internal electron donor, a catalyst comprising the catalyst component, and use of the catalyst in olefin polymerization. When used in propylene polymerization, the catalyst can exhibit good catalytic activity and good hydrogen response, and the resulting polymer can have a good isotacticity and a good molecular weight distribution.

Abstract: The present invention relates to catalysts systems for the polymerization of ethylene and its mixtures with olefins CH2?CHR, wherein R is an alkyl, cycloalkyl or aryl radical having 1-12 carbon atoms, comprising (A) a solid catalyst component comprising Ti, Mg, halogen, (B) an aluminum alkyl compound and (C) an an acetal of formula HnC(OR1)4-n where n is O, 1 or 2 and R1 is C1-C10 hydrocarbon group.

Abstract: This invention relates to an improved method for improving the tacticity of Ziegler-Natta catalyst systems and for controlling the behaviour of the active stereospecific sites.

Abstract: Prepolymerized catalyst component for the polymerization of olefins CH2?CHR in which R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, having average particle size equal to or lower than 30 ?m comprising a solid catalyst component comprising magnesium halide, a titanium compound having at least a Ti-halogen bond and at least two electron donor compounds one of which being selected from 1,3-diethers and the other one being selected from esters of aromatic mono or dicarboxylic acids, said solid catalyst component being prepolymerized with an olefin, having from 2 to 10 carbon atoms, to such an extent that the amount of the olefin prepolymer is equal to or lower than 50 g per g of solid catalyst component.

Abstract: A catalyst composition for the polymerization of propylene is provided. The catalyst composition includes one or more Ziegler-Natta procatalyst compositions having one or more transition metal compounds and an internal electron donor, one or more aluminum containing cocatalysts, and an external electron donor. The internal electron donor is a bidentate compound excluding plithalates. Suitable bidentale compounds include diethers, succinates, dialkoxybenzenes and diol esters. The external electron donor is a mixture of an activity limiting agent and selectivity determining agent. The present catalyst composition has high catalyst activity and high stereoselectivity, and is self-extinguishing.

Abstract: Disclosed are procatalyst compositions having an internal electron donor which includes an adamantanedicarboxylate and optionally an electron donor component. Ziegler-Natta catalyst compositions containing the present procatalyst compositions produce propylene-based olefins with broad molecular weight distribution.

Abstract: Catalyst components for the polymerization of olefins comprising Mg, Ti, halogen and 1,3-diethers as internal donors having an improved balance of properties in terms of activity and morphological stability are obtained by a process comprising: (A) A first step comprising reacting an adduct of formula MgCl2(ROH)n, where R is a C1-C10 alkyl group, and n is from 0.5 to 6, with a titanium compound having at least a Ti—Cl bond at a reaction temperature ranging from 0° C. to 80° C.; (B) A subsequent step comprising contacting the solid product obtained in (A) with an electron donor ED selected from 1,3 diethers with a titanium compound having at least a Ti—Cl bond at a temperature higher than 80° C.; and (C) A subsequent step comprising reacting the solid product coming from (B) with a titanium compound having at least a Ti—Cl bond at a temperature higher than 80° C.

Abstract: Disclosed are catalyst compositions having an external electron donor which includes one or more of the following compositions: a phosphite, a phosphonite, a pyrophosphite, and/or a diphosphazane. Ziegler-Natta catalyst compositions containing the present external electron donor exhibit strong activity and produce propylene-based olefins with high isotacticity and high melt flow rate.

Abstract: Disclosed are procatalyst compositions having an internal electron donor which include a substituted phenylene aromatic diester and optionally an electron donor component. Ziegler-Natta catalyst compositions containing the present procatalyst compositions exhibit high activity and produce propylene-based olefins with broad molecular weight distribution.

Abstract: Disclosed herein are processes for preparing procatalyst compositions and polymers, i.e., propylene-based polymers, produced therefrom. The present procatalyst compositions improve catalyst selectivity and also increase the bulk density of the formant polymer.

Abstract: A process for preparing a polydiene, the process comprising the step of polymerizing conjugated diene monomer in the presence of a dihydrocarbyl ether, where said step of polymerizing employs a lanthanide-based catalyst system.

Abstract: A transition metal complex of the following formula (1): in which A represents an atom of Group 16 of the periodic table; B1 represents an atom of Group 14 of the periodic table; M1 represents a transition metal atom of Group 4 of the periodic table; Cp1 represents a group having a cyclopentadiene anion backbone; R1, R2, R3, R4, R5 and R6 represent independently of one another a hydrogen atom, a halogen atom, a C1-20 alkyl group optionally substituted with a halogen atom; R7, R8, R9, R10, R11 and R12 represent independently of one another a hydrogen atom, a C1-20 alkyl group optionally substituted with a halogen atom; and a 1,3-diene comprising R7, R8, R9, R10, R11, R12 and 4 carbon atoms coordinates on M1, and the 1,3-diene may be of either a cis or trans form, or a mixed form thereof, although the coordination form is not limited, and the double bonds may be delocalized.

Abstract: This invention relates to an improved method for improving the tacticity of Ziegler-Natta catalyst systems and for controlling the behaviour of the active stereospecific sites.

Abstract: Methods and apparatus to form a catalyst precursor, comprising combining in a reactor magnesium, an alkoxysilane compound, a halogenized silicon compound, a halogenized transition metal compound, a substituted aromatic furan compound having a structural formula, and an alkyl halide or aromatic halide compound to obtain a solid catalyst precursor, wherein the alkoxysilane compound and halogenized silicon compound are combined prior to either being exposed to the halogenized transition metal compound, and wherein the alkyl halide or aromatic halide compound is introduced to the reactor as the final step.

Abstract: The present invention relates to a preparation method of solid titanium catalyst for olefin polymerization comprising the steps of: (1) preparing a magnesium compound solution by dissolving a magnesium halide compound into a mixed solvent of a cyclic ether and one or more of alcohol; (2) preparing a carrier by adding firstly a titanium halide compound to the magnesium compound solution at low temperature, elevating the temperature of the resulted solution or aging it, and then thereto adding secondly the titanium halide compound additionally; (3) preparing a titanium catalyst by reacting the carrier with a titanium compound and an electron donor; and (4) washing the titanium catalyst with hydrocarbon solvent at high temperature.

Abstract: A catalyst component for the polymerization of olefins comprising a titanium compound, a Mg-dihalide, a difunctional electron donor compound (ED) selected from diesters, diketones, diamines or diethers, and a monofunctional electron donor compound (MD) selected from ethers, esters, amines or ketones, wherein a molar ratio ED/MD is higher than 10.

Abstract: The present invention relates to a solid catalyst component for the polymerization of olefins CH2?CHR in which R is hydrogen or a hydrocarbon radical with 1-12 carbon atoms, comprising Mg, Ti, halogen and an electron donor selected from ?-keto-ester derivatives of a particular formula. Said catalyst components when used in the polymerization of olefins, and in particular of propylene, are capable to give polymers in high yields and with high isotactic index expressed in terms of high xylene insolubility.

Abstract: A catalyst component for olefin (co)polymerization, and in particular for the preparation of LLDPE, comprising Mg, Ti, halogen and an electron donor compound (ED) belonging to ethers, esters, amines, ketones, or nitriles, characterized in that the molar ratio Mg/Ti is higher than 5, and the molar ratio ED/Ti is higher than 3.5. The said catalyst components display a homogeneous distribution of the comonomer in and among the copolymer chains.

Abstract: The present invention provides a high-activity solid main catalyst component for ethylene polymerization, a process for preparing the same and a catalyst containing the same. The main catalyst component consists essentially of a magnesium compound, a titanium compound, an electron donor, an alkyl aluminum compound and fumed silica, and is prepared by a process comprising the step of: reacting powdered magnesium with an alkyl halide to form a magnesium compound in the nascent state; adding the magnesium compound in the nascent state together with a titanium compound and an alkyl aluminum compound into an electron donor to form a complex; adding and well dispersing a fumed silica thereto to form a homogeneous thick mixture; molding and drying the mixture to form main catalyst component particles with good particle morphology; and optionally, dispersing the main catalyst component particles into a hydrocarbon solvent or a mineral oil to form a slurry.

Abstract: The present invention relates to a propylene random copolymer which satisfies the following requirements [1] to [4], and to various useful molded products obtained by molding the propylene random copolymer: [1] the concentration (Pa, % by mole) of a skeletal constituent derived from propylene (a), and the concentration (Px, % by mole) of a skeletal constituent derived from at least one olefin selected from ethylene (b) and ?-olefins having 4 to 20 carbon atoms (c), each of which is contained in the propylene random copolymer, satisfy the following relational expressions (Eq-1) to (Eq-3): 85?Pa<100??(Eq-1) 0<Px?15??(Eq-2) Pa+Px=100;??(Eq-3) [2] the concentration (Pa, % by mole) of the skeletal constituent derived from propylene (a) contained in the propylene random copolymer, and the melting point (Tm) measured with a differential scanning calorimeter satisfy the following relational expression (Eq-4): 135?4×(100?Pa)<Tm<165?4×(100?Pa);??(Eq-4) [3] the total amount of 2,1-bonded and 1,3-bon

Abstract: The present invention relates to a catalyst component and a catalyst for olefin polymerization. The catalyst component utilizes magnesium halide and silica as composite support, and the particle morphology thereof can be improved by regulating the ratio of magnesium halide to silica. Further, the purpose of stabilizing the rate of catalytic polymerization reaction and improving the particle morphology of polymer so as to meet the requirements on catalyst performance of various polymerization processes can be achieved through the combination of the supports of the catalyst. In the meantime, when used in the polymerization of propylene, the catalyst of the present invention exhibits a relatively high polymerization activity and high stereospecificity.

Abstract: The present application discloses a catalyst for olefin polymerization, comprising a product of the following components: (A) solid titanium-containing catalyst component comprising magnesium, titanium and halogen as essential components; (B) organo-aluminum compound catalyst component, and (C) silicon ether compound catalyst component, the silicon ether compound being represented by a general formula (I): wherein R1-R12 and A are as defined in the description.

Abstract: Catalyst component for the polymerization of olefins obtainable by contacting: (i) a magnesium halide, or a suitable precursor; (ii) a monofunctional electron donor compound (MD) selected from ethers, esters, amines or ketones, used in such amounts to have Mg/MD molar ratios of at least 50; (iii) a titanium compound of formula Ti(ORI)n-yXy, where n is the valence of titanium, y is a number between 1 and n, X is halogen, and RI is a C1-C15 hydrocarbon group and, optionally, (iv) an electron donor compound (ED). The said catalyst component shows improved activity in the polymerization of olefins.