Abstract: In catalyst systems of the Ziegler-Natta type comprising as active constituentsa) a titanium-containing solid component which is obtained by reacting a compound of titanium with a compound of magnesium, a halogen, an inorganic oxide as support, a C.sub.1 -C.sub.8 -alkanol and a carboxylic ester as electron donor compound,and also as cocatalyst,b) an aluminum compound andc) if desired, a further electron donor compound,the reaction of the individual components for preparing the titanium-containing solid component a) is carried out in the presence of an aromatic hydrocarbon as solvent.

Abstract: Procedure for the preparation of a solid carrier for olefin polymerization catalysts, comprising the steps:a) impregnating a silica with Mg-chloride solubilized in ethylbenzoate, in the presence of further electron donors,b) optionally drying the impregnated silica obtained in (a) and impregnating it with a solution of Mg-alkyls in SiCl.sub.4 at a temperature from -10 to 20.degree. C. and subsequently treating the obtained slurry at a temperature from 40.degree. C. to reflux temperature, optionally adding a further amount of electron donors,c) drying the obtained carrier.The carrier which is obtained according to the above procedure is advantageously used for the preparation of supported catalysts for the polymerization of olefins.

Abstract: A catalyst composition for the polymerization of olefins is provided, which comprises the reaction product of a spirocycle, a complex of an atom selected from Groups 3-14 and the Lanthanides, and an activating cocatalyst.

Abstract: This invention is generally directed toward a supported catalyst system useful for polymerizing olefins. The method for supporting the catalyst system of the invention provides for a metallocene catalyst and alumoxane activator supported on a porous support using a total volume of catalyst solution that is less than that of which a slurry is formed. The metallocene and alumoxane aer mixed in solution, then the solution is added to a porous support in a volume between the total pore volume of the support and the volume at which a slurry forms. The solvent is then removed, leaving an activated supported metallocene.

Abstract: It has been found that the use of at least one unsupported metallocene polymerization catalyst with at least one supported metallocene polymerization catalyst in the polymerization of olefins allows for better control of the polymerization, especially gas phase polymerization. Such a system takes advantage of the high activity of the unsupported catalyst and the stability of a supported catalyst. Additionally, the relative timing of the addition of the supported and unsupported catalysts to a reaction system can be used to control a continuous polymerization reaction by stabilizing the reactor bed with the supported catalyst prior to addition of the unsupported catalyst.

Abstract: A transition metal complex represented by the formula [1] ##STR1## wherein M is a transition metal atom of the group 4 of the periodic table of elements; Cp is a group having a cyclopentadiene type anionic skeleton; A and G are each a divalent residue containing an atom of the group 15 or 16 of the periodic table of elements and may be the same with or different from each other; X.sup.1, X.sup.2, R.sup.1, R.sup.2, R.sup.3 and R.sup.

Abstract: A catalyst composition for the polymerization of olefins is provided, which comprises the reaction product of a fulvene, a complex of an atom selected from Groups 3-14 and the Lanthanides, and an activating cocatalyst.

Abstract: A particulate phyllosilicate mixture comprising a mixture containing a phyllosilicte belonging to the smectite group and a phyllosilicate belogning to the mica group, the phyllosilicate particle having a content of the phyllosilicate belonging to the smectite group of 0.1 to 50% by weight and optionally satisfying the following requirements (a) to (c):(a): the average particle diameter is 20 to 1000 .mu.m with not more than 20% of the total number of particles being accounted for by particles having a particle diameter of not more than 10 .mu.m;(b): the crushing strength of the particle is not less than 0.5 MPa as measured with a microcompression tester and(c): the bulk density of the particle of not less than 0.6 g/cm.sup.3.Polymerization of olefins with catalyst comprising the particulate phyllosilicate mixture as a carrier or support for the catalysts is also disclosed.

Abstract: The present invention relates to a solid catalyst component for the polymerization of olefins CH.sub.2 .dbd.CHR in which R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, comprising a titanium compound, having at least a Ti-halogen bond and an electron donor compound supported on a Mg halide, in which said electron donor compound is selected from esters of malonic acids of formula (I): ##STR1## wherein R.sub.1 is a C.sub.5 -C.sub.20 linear or branched alkyl, a C.sub.5 -C.sub.20 cycloalkyl, a C.sub.7 -C.sub.20 arylalkyl or alkylaryl group; R.sub.2 and R.sub.3, equal to or different from each other, are C.sub.1 -C.sub.3 alkyl, cycloalkyl. Said catalyst components when used in the polymerization of olefins, and in particular of propylene, are capable to give high yields and polymers having high insolubility in xylene.

Abstract: The present invention concerns prepolymerized catalyst composition for polymerization of .beta.-olefins, a process for the preparation thereof and a process for polymerization of .beta.-olefins. According to the polymerization process a procatalyst composition containing a transition metal is prepolymerized with a monomer in order to produce a prepolymerized Ziegler-Natta type catalyst composition and said catalyst composition is contacted with an alpha-olefin monomer, in particular with ethylene or propylene, for preparing a polymer. According to the invention the procatalyst composition is preferably prepolymerized in a medium which is inert to the catalyst components, the viscosity of the medium being so high that the catalyst does not substantially settle in this medium. Because the catalyst composition according to the invention does not have to be dried before being fed into the medium, its activity is high before and during polymerization.

Abstract: Group 4 metal constrained geometry complexes comprising a fused ring indenyl derivative ligand, catalytic derivatives thereof, processes for preparing the same and their use as components of olefin polymerization catalysts are disclosed.

Abstract: An olefin polymerization catalyst comprising (A) a solid catalyst component and (B) an organometallic compound component. The solid catalyst component (A) is prepared by a process comprising the steps of:(I) obtaining a solid (A-1) by reacting:(i) an organomagnesium component soluble in a hydrocarbon solvent and represented by the formula (M.sup.1).sub..alpha. (Mg).sub..beta. (R.sup.1).sub.p (R.sup.2).sub.q (OR.sup.3).sub.r ; and(ii) an Si--H bond-containing chlorosilane compound represented by the formula: H.sub.a SiCl.sub.b R.sup.4.sub.4-(a+b), in a ratio of from 0.01 to 100 mol (ii) per mol (i);(II) reacting the solid (A-1) with an alcohol (A-2) in a ratio of from 0.05 to 20 mol of the alcohol per mol of C--Mg bonds contained in the solid (A-1), to form a reaction product; and(III) reacting the reaction product with a titanium compound (A-4). The solid catalyst component (A) is adjusted to have an alkoxy group/titanium molar ratio of 2.4 or lower and an alkoxy group/magnesium molar ratio of 0.15 or lower.

Abstract: Catalysts for polymerizing olefins, diolefins and/or acetylenically unsaturated monomers comprising biscyclopentadienyl, Group 4 transition metal complexes formed with conjugated dienes wherein the diene is bound to the transition metal either in the form of a .sigma.-complex or a .pi.-complex in combination with a cocatalyst or subjected to bulk electrolysis in the presence of compatible, inert non-coordinating anions.

Abstract: Disclosed is a catalyst precursor, useful to make catalysts useful in the polymerization of olefins, comprising the product obtained by adding a preformed magnesium source to a solution comprising a solvent having dissolved therein a transition metal compound and an alkyl halide.

Abstract: A method of making a solid, substantially dry olefin polymerization procatalyst precursor is disclosed whereby a solid precursor containing magnesium and titanium is formed in a slurry or solution, the solid then is separated from the solution and then dried at a temperature above 50.degree. C. for over an hour. Solid, substantially dry olefin polymerization procatalyst precursors made by the method also are disclosed, whereby the precursors are easier to handle, have better flowability, reduced clumpness and provide catalysts that can be used to produce polymers having improved extrudability, less filter clogging, less "talc"-like polymer particles of <10 micron in size and reduced polymer product segregation in storage.

Abstract: A process for polymerizing a gaseous conjugated diene by bringing it in contact with a catalyst consisting of a rare earth allyl compound, an organic aluminum compound, an inorganic support and optionally, the same or a different conjugated diene. The resulting polymers possess elevated proportions of cis-1,4 units.

Abstract: Disclosed is a process for preparing a solid titanium catalyst component, comprising contacting (a) a liquid magnesium compound, (b) a liquid titanium compound, (c) an electron donor and (d) a solid divalent metallic halide. In this process, the solid divalent metallic halide is one having a crystalline structure of the cadmium chloride type. The contact of the component (a) with the component (b) is preferably carried out in the presence of the solid divalent metallic halide (d). According to this process, there can be obtained a solid titanium catalyst component capable of polymerizing olefins with an extremely high activity and capable of producing polyolefins of high stereoregularity when .alpha.-olefins of 3 or more carbon atoms are polymerized.

Abstract: A catalyst for polymerizing an olefin, which comprises (A) a metallocene transition metal compound, (B) (1) an ion-exchanging layered compound other than a silicate or (2) an inorganic silicate prepared by treating a starting ion-exchanging layer compound other than a silicate or a starting silicate with a salt, an acid, or a combination thereof, said component (B) having a water content not higher than 1% by weight which is obtained by heat-dehydrating component (B) under an inert gas atmosphere or under reduced pressure, and (C) an organoaluminum compound.

Abstract: An catalyst composition for preparing high-syndiotacticity polystyrene polymers which comprises: (a) a titanium complex represented by the following formula of TiR'.sub.1 R'.sub.2 R'.sub.3 R'.sub.4 or TiR'.sub.1 R'.sub.2 R'.sub.3, wherein R'.sub.1, R'.sub.2, R'.sub.3, and R'.sub.4 are, independently, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group, a hydrogen atom, or a halogen atom; (b) a cyclopentadienyl complex of silicon (Si), germanium (Ge), or tin (Sn) represented by the following formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.

Abstract: The present invention provides an ethylene copolymer comprising constituent units (a) derived from ethylene and constituent units (b) derived from an .alpha.-olefin having 3 to 20 carbon atoms, the ethylene copolymer being characterized in that(A) the ethylene copolymer has a density (d) of 0.86 to 0.95 g/cm.sup.3 ;(B) the ethylene copolymer has a MFR of 0.001 to 50 g/10 min as measured at a temperature of 190.degree. C. and a load of 2.16 kg;(C) the melt tension (MT) and MFR of the ethylene copolymer satisfy the relationlog MT>-0.66 log MFR+0.6; and(D) the temperature (T) at which the exothermic curve of the ethylene copolymer measured by a differential scanning calorimeter (DSC) shows the highest peak and the density (d) satisfy the relationT<400 d-250.

Abstract: The present invention concerns heterogeneous catalysts for polymerization of olefins. The catalysts include at least one Group IVa metal compound on a solid inorganic oxidic support. According to the invention the catalysts are prepared by vapourizing at least one solid Group IVa metal halide compound and routing the vapour of the metal halide compound into a reaction chamber, wherein the vapour is reacted with the support at a temperature of about 250.degree. to about 450.degree. C. in order to bind said metal halide compound to said support. Any metal compound not bound to said support as well as any volatile reaction products emanating from the reaction between said metal halide compound and said support are then removed from the reaction chamber in the vapour phase. Optionally, the product obtained is treated with an organic aluminum compound to increase the catalytic activity of said catalyst.

Abstract: Catalysts comprisingA) a rare earth alkoxide, a rare earth carboxylate and/or a rare earth coordination compound with diketones,B) an alumoxane andC) an inert, particulate, inorganic solid with a specific surface area of greater than 10 m.sup.2 /g and a pore volume of 0.3 to 15 ml/gare excellently suited to the polymerisation of conjugated dienes, in particular butadiene, in the gas phase.

Abstract: Catalysts consisting ofA) an alcoholate of the rare earths, a carboxylate of the rare earths, a complex compound of the rare earths with diketones and/or an addition compound of the halides of the rare earths with an oxygen or nitrogen donor compound,B) an aluminium trialkyl, a dialkyl aluminium hydride and/or an alumoxane,C) another Lewis acid andD) an inert, particulate inorganic solid with a specific surface of greater than 10 m.sup.2 /g (BET) and a pore volume of 0.3 to 15 ml/gare eminently suitable for the polymerization of conjugated dienes, more particularly butadiene, in the gas phase.

Abstract: The invention relates to a reagent which is useful for the synthesis of oxysulphide-containing fluorine-containing organic derivatives by reacting with an oxide of sulphur, especially sulphur dioxide, characterized in that it comprises:a) a fluorocarboxylic acid of formula E.sub.w --CF.sub.2 --COOH where E.sub.w is an electron-withdrawing group or atom which is at least partially salified by an organic or inorganic cation, andb) an aprotic polar solvent; andin that the content of releasable protons carried by its various components, including their impurities, is at most equal to half the initial molar concentration of the said fluorocarboxylic acid.This reagent can be used by heating in order to form fluorine-containing sulphinic or sulphonic acids.

Abstract: A supported catalyst component comprising (a) a support material, an organometal compound, and (b) an activator compound comprising b.1) a cation which is capable of reacting with a transition metal metallocene compound to form a catalytically active transition metal complex, and b.2) a compatible anion having up to 100 nonhydrogen atoms and containing at least one substituent comprising an active hydrogen moiety; a supported catalyst comprising the supported catalyst component and a transition metal compound; process for making the same; an addition polymerization process using the supported catalyst; complex compounds, and a method for preparing the same.

Abstract: A catalyst component is disclosed for use in the homo- or copolymerization of olefinic hydrocarbons. The catalyst component is comprised of a first compound of the formula M.sup.1 (OR.sup.1).sub.p R.sup.2.sub.q X.sup.1.sub.4-p-q, M.sup.1 being titanium a second compound of the formula M.sup.2 (OR.sup.3).sub.m R.sup.4.sub.n X.sup.2.sub.z-m-n, with M.sup.2 being a metal of Groups Ia-IIIa or IIb of the Periodic Table, and a third compound which is an organocyclic compound having two or more conjugated double bonds. A process is also disclosed for the production of hydrocarbon polymers in which the above catalyst component is combined with a modified organoaluminum compound to form a catalyst composition capable of providing controlled molecular weight, wide distribution thereof and other desirable qualities in the polymer product.

Abstract: A catalyst for olefin polymerization is provided which comprises, as the components, a) a metallocene compound, b) an ionizing ionic compound, c) an organoaluminum compound, and d) a Lewis base compound. This catalyst has a stable active species and improves productivity of an olefin polymer without deterioration of the catalytic activity the metallocene is represented by General Formula (1) or (2) where Cp-containing ligands may be Cp, fluorenyl, indenyl or tetrahydroindenyl and where the metal is a group 4 metal of the periodic table.

Abstract: A non-supported solid catalyst comprising (a) an ionic compound comprising a.1) a cation and a.2) an anion having up to 100 nonhydrogen atoms and said anion containing at least one substituent comprising an active hydrogen moiety, (b) a transition metal compound, and (c) an organometal compound wherein the metal is selected from the Groups 1-14 of the Periodic Table of the Elements; a supported solid catalyst comprising (a), (b), (c), and (d) a support material, obtainable by combining components (a), (b), (c), and (d) in any order, and wherein during at least one step in the preparation of the solid catalyst, component (a) dissolved in a diluent in which (a) is soluble, is converted into solid form; a method for preparing the solid catalysts; and a process of polymerization using these solid catalysts.

Abstract: Catalyst systems of the Ziegler-Natta type comprising as active constituentsa) a titanium-containing solid component prepared using a titanium compound, a compound of magnesium, a halogenating agent and an electron donor component,b) an aluminum compound andc) as further electron donor component, an organosilicon compound of the formula (I)R.sup.1 R.sup.2 si(OR.sup.3).sub.2 (I)in whichR.sup.1 is a C.sub.1 -C.sub.10 -alkyl radical or a C.sub.3 -C.sub.8 -cycloalkyl radical, R.sup.2 is a 2,4,4,6,6-pentamethylheptyl radical andR.sup.3 is a C.sub.1 -C.sub.8 -alkyl radical,are particularly suitable for the preparation of polymers of C.sub.2 -C.sub.10 -alk-1-enes.

Abstract: Novel Group 4 metal complexes containing one and only one cyclic delocalized, anionic, .pi.-bonded group wherein the metal is in the +4 formal oxidation state and having a bridged ligand structure, also referred to as constrained geometry complexes and a conjugated diene divalent anionic ligand group; catalytic derivatives of such complexes including novel zwiterionic complexes; and the use thereof as catalysts for polymerizing olefins, diolefins and/or acetylenically unsaturated monomers.

Abstract: An olefin polymerization catalyst includes a halogen-containing magnesium compound; a titanium compound; and an additive selected from the group consisting of (a) a mixture of an aluminum alkoxide compound and polydimethylsiloxane, (b) an aluminosiloxane, (c) the reaction product of an aluminum alkyl and a calixarene, (d) the reaction product of an aluminum alkyl and a cyclodextrin, and mixtures of (a)-(d).

Abstract: This invention relates to a process for making a catalyst in which a metallocene is included in the synthesis of a Ziegler-Natta catalyst and a process for using the catalyst in the polymerization of olefins, specifically, propylene, to produce a polymer product with broad polydisperisty.The catalyst may be synthesized by:1) selecting a solid component comprising a magnesium dialkoxide;2) adding a chlorinating agent;3) adding a titanating agent;4) adding a metallocene prior to step 2), after step 2), prior to step 3) or after step 3) and5) adding an aluminum alkyl cocatalyst.

Abstract: The present invention relates to components of catalysts for the polymerization of olefins comprising the product that can be obtained by bringing a compound of a transition metal M, containing at least one M--.pi. bond, into contact with an olefinic prepolymer obtained by polymerization of one or more olefins with a coordination catalyst comprising a compound of Ti or V supported on a magnesium halide.

Abstract: An olefin homogeneous polymerization catalyst demonstrating increased activity is formed from a cyclopentadienyl metallocene component, a salt of a compatible cation and a non-coordinating anion, and a C.sub.3 -C.sub.6 trialkylaluminum, preferably triisobutylaluminum. A homogeneous polymerization process comprises controlling polymerization activity with such catalyst by controlling the aluminum/metal (Al/M) molar ratio to a minimal level within the effective range of Al/M ratios.

Abstract: Catalyst support containing an .alpha.-olefin polymer which is in the form of particles of mean size from 5 to 350 .mu.m in which the pore volume generated by the pores of radius from 1,000 to 75,000 .ANG. is at least 0.2 cm.sup.3 /g.Catalyst usable for the polymerization of .alpha.-olefins, including a compound containing at least one transition metal belonging to groups IIIb, IVb, IVb and VIb of the Periodic Table, bound in or on this support.

Abstract: A composition which can be used in, for example, slurry polymerization of an olefin such as, for example, ethylene is produced by a process comprising: (1) combining a first transition metal compound and a metal halide to form a solution; (2) contacting the solution with a precipitating agent to form a solid catalyst intermediate; (3) contacting the solid catalyst intermediate with a second transition metal compound to produce a catalyst composition; and optionally (4) depositing a prepolymer onto the catalyst composition. The precipitating agent comprises a sufficient amount of both a Lewis acid and an ether to effect the precipitation of a solid. Also disclosed is the use of the composition in polymerization of an olefin.

Abstract: A catalyst for producing a styrenic polymer which comprises an (A) transition metal compound having one and only one .pi.-ligand comprising only one indenyl group, said indenyl group bearing a substituent group at at least the 1-, 2-, or 3-positions of the indenyl ring, and wherein the transition metal is preferably at least one metal selected from the group consisting of titanium, zirconium, hafnium, niobium and tantalum, and optionally (B) at least one compound selected from the group consisting of 1 an aluminoxane and 2 an ionic compound comprising an anion that does not coordinate to the transition metal compound of component (A) in its cationic form, and a cation, and further optionally (C) a Lewis acid; and a process for producing a styrenic polymer using the catalyst.

Abstract: The present invention relates to a process for the preparation of a solid catalytic component of a catalyst of Ziegler-Natta type, comprising contacting (i) at least one compound (A) of a transition metal (TM) with (ii) a solid product (B) comprising a magnesium compound and having a reducing power for the transition metal (TM), in the presence of (iii) at least one olefin under conditions such that the olefin at least partially polymerizes during the contacting. The solid catalytic component is particularly useful for producing ethylene (co-)polymers in a gas phase process and for improving the statistical distribution of the comonomer in the copolymer structure.

Abstract: This invention relates to a conventional supported heterogeneous Ziegler-Natta catalyst for the polymerization of olefins. It has been found that adding a lithium compound to a transition metal catalyst component and then adding an organoaluminum co-catalyst and an organosilicon electron donor produces a catalyst which yields polymer with increased molecular weight. The lithium compound is of the general formula LiCp wherein Cp is a cyclopentadienyl or substituted cyclopentadienyl and is preferably lithium cyclopentadienide or lithium indene. Preferably, the molar ratio of lithium compound/transition metal is at least 0.2.

Abstract: A process for preparing a supported metallocene/aluminoxane solid catalyst comprises preparing a water-in-oil emulsion of water and an inert solvent by using an emulsifier, adding dropwise the emulsion to a solution of an organoaluminium compound in an inert solvent to carry out the reaction to obtain a suspension of the particulate aluminoxane, followed by adding a solution of a metallocene to the above suspension to support the metallocene on the aluminoxane. The solid catalyst thus obtained can be used in the polymerization and copolymerization of olefins. Polymerization can be carried out by slurry polymerization, bulk polymerization, gas phase polymerization, etc.

Abstract: A catalyst composition comprising a bis-amide compound represented by the formula ##STR1## wherein M is zirconium, hafnium or titanium; each N is a three coordinate nitrogen atom; each e is Si, Ge or Sn; each Z is, independently, a hydride or R; each R is, independently, a hydrocarbyl one or more carbon atoms of which may be substituted by an element selected from Si, O, P, N and S; L is a neutral Lewis base and m is a number from 0 to 2; or a dimer thereof and a second component. Preferably the second component is a compound which is capable of providing a bulky and labile anion ?A!.sup.-, which anion is substantially non-coordinating under the reaction conditions and contains at least one boron atom. Also provided is a process for oligomerizing or co-oligomerizing alpha olefins in the presence of this catalyst composition.

Abstract: Addition polymerization catalysts-comprising 1) a Group 4 metal complex in the .sup.+ 3 oxidation state containing two delocalized .pi.-bonding moieties, and a stabilizing ligand covalently bonded to the metal and also datively bonded to the metal via lone pair electrons of an amine, phosphine, ether or thioether group and 2) an activating cocatalyst.

Abstract: A catalyst component useful in the polymerization of olefins which includes a support formed of a copolymer of an olefin and a silane monomer having at least one unsaturated hydrocaryl substitutent. A process for making the catalyst component as well as a catalyst composition which includes the catalyst component is also set forth.

Abstract: An catalyst composition for preparing high-syndiotacticity polystyrene polymers which comprises: (a) a titanium complex represented by the following formula of TiR'.sub.1 R'.sub.2 R'.sub.3 R'.sub.4 or TiR'.sub.1 R'.sub.2 R'.sub.3, wherein R'.sub.1, R'.sub.2, R'.sub.3, and R'.sub.4 are, independently, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group, a hydrogen atom, or a halogen atom; (b) a cyclopentadienyl complex of silicon (Si), germanium (Ge), or tin (Sn) represented by the following formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.

Abstract: A catalyst component is disclosed for use in the homo- or copolymerization of olefinic hydrocarbons. The catalyst component is comprised of a first compound of the formula Me.sup.1 (OR.sup.1).sub.p R.sup.2.sub.q X.sup.1.sub.4-p-q and a second compound which is an organocyclic compound having two or more conjugated double bonds. A process is also disclosed for the production of hydrocarbon polymers in which the above catalyst component is combined with a modified or organoaluminum compound to form a catalyst composition capable of providing high molecular weight, wide distribution thereof and other desirable qualities in the polymer product.

Abstract: The present invention concerns prepolymerized catalyst composition for polymerization of .alpha.-olefins, a process for the preparation thereof and a process for polymerization of .alpha.-olefins. According to the polymerization process a procatalyst composition containing a transition metal is prepolymerized with a monomer in order to produce a prepolymerized Ziegler-Natta type catalyst composition and said catalyst composition is contacted with an alpha-olefin monomer, in particular with ethylene or propylene, for preparing a polymer. According to the invention the procatalyst composition is preferably prepolymerized in a medium which is inert to the catalyst components, the viscosity of the medium being so high that the catalyst does not substantially settle in this medium. Because the catalyst composition according to the invention does not have to be dried before being fed into the medium, its activity is high before and during polymerization.

Abstract: There are disclosed a transition metal compound of the general formula RMX.sub.a-1 L.sub.b (R is as a .pi. ligand, a fused polycyclic cyclopentadienyl group in which at least one of many-membered rings to which cyclopentadienyl groups are fusedly bonded is a saturated ring, M is a transition metal, X is a .sigma. ligand, L is a Lewis base, a is the valency of M, and b is 0, 1 or 2); a polymerization catalyst for styrene, etc. comprising the above transition metal, preferably further comprising an oxygen atom containing compound ionic compound or organoboron compound and optionally a Lewis base; and a process for producing a polymer of a compound containing an ethylenically unsaturated double bond or an acetylenic polymer, especially a syndiotactic polystyrene by using the above polymerization catalyst. The catalyst is particularly effectivive for producing highly syndiotactic polystyrene minimized in residual metals amounts at a low cost in enhanced efficiency.

Abstract: A procatalyst composition which is suitable for the homo- and copolymerization of alpha olefins together with an organometallic cocatalyst compound and which is prepared by treating an inorganic carrier with a component system containing a complex of a magnesium halide and a tetraalkyl titanate, and a chlorinating compound which does not contain a transition metal compound. In order to raise the Mg:Ti ratio, the component system additionally contains an organomagnesium compound.

Abstract: A catalyst for olefin polymerization is provided which comprises, as the components, a) a metallocene compound, b) an ionizing ionic compound, c) an organoaluminum compound, and d) a Lewis base compound. This catalyst has a stable active species and improves productivity of an olefin polymer without deterioration of the catalytic activity.

Abstract: There are disclosed a transition metal compound of the general formula RMX.sub.a-1 L.sub.b (R is a .pi. ligand, a fused polycyclic cyclopentadienyl group in which at least one of many-membered rings to which cyclopentadienyl groups are fusedly bonded is a saturated ring, M is a transition metal, X is a .sigma. ligand, L is a Lewis base, a is the valency of M, and b is 0, 1 or 2); a polymerization catalyst for styrene, etc. comprising the above transition metal, preferably further comprising an oxygen atom containing compound ionic compound or organoboron compound and optionally a Lewis base; and a process for producing a polymer of a compound containing an ethylenically unsaturated double bond or an acetylenic polymer, especially a syndiotactic polystyrene by using the above polymerization catalyst. The catalyst is particularly effective for producing highly syndiotactic polystyrene minimized in residual metals amounts at a low cost in enhanced efficiency.