Abstract: A method of recovering a solvent including: supplying polymerization reactants including one or more monomers and a solvent to a reactor to obtain a polymer solution; supplying a stream including the polymer solution to a separator to separate an upper discharge stream including the solvent, wherein the solvent is in a gaseous phase, and a lower discharge stream including the polymer solution; heating a divergence stream including a part of the lower discharge stream from the separator by a heating device and refluxing the divergence stream to the separator; supplying a residue stream including a remainder of the lower discharge stream from the separator to a steam stripping process unit; and adjusting a vapor mass fraction of the divergence stream which is refluxed to the separator with a pressure adjustment valve after being heated by the heating device.

Abstract: The present invention relates to a method for improving the cooling capacity of a gas solids olefin polymerization reactor by splitting the fluidization gas and returning part of the fluidization gas to the reactor into the bottom zone of the reactor and another part of the fluidization gas directly into the dense phase formed by particles of a polymer of the at least one olefin suspended in an upwards flowing stream of the fluidization gas in the middle zone of the reactor.

Abstract: A process for making an ethylene homopolymer in the presence of an oxide-supported chromium catalyst is disclosed. A small amount of an ?-olefin contacted with the catalyst before polymerizing ethylene or introduced into an ethylene homopolymerization unexpectedly boosts process productivity. When used at part per million levels, the ?-olefin improves productivity while maintaining desirable polymer properties. The invention is particularly valuable for making HDPE resins useful for blow molding applications.

Abstract: A method for polymerizing conjugated diene monomer into polydienes, the method comprising: polymerizing conjugated diene monomer within a liquid-phase polymerization mixture that includes conjugated diene monomer, a lanthanide-based catalyst system, dicyclopentadiene or substituted dicyclopentadiene, and optionally organic solvent, with the proviso that the organic solvent, if present, is less than about 20% by weight based on the total weight of the polymerization mixture.

Abstract: Shear-thinning ethylene/?-olefin and ethylene/?-olefin/diene monomer interpolymers that do not include a traditional branch-inducing monomer such as norbornadiene are prepared at an elevated temperature in an atmosphere that has little or no hydrogen using a constrained geometry complex catalyst and an activating cocatalyst.

Abstract: A polyethylene composition prepared by polymerizing ethylene and an optional olefin with ?3 carbon atoms in the presence of a macromonomer, is provided. The macromonomer is a vinyl-terminated ethylene polymer prepared by polymerizing ethylene and an optional olefin with ?3 carbon atoms, and the macromonomer has (A) Mn?5,000, and Mw/Mn=2-5. The polyethylene composition comprises (C) branched polyethylene prepared by copolymerizing ethylene, the macromonomer and an optional olefin with ?3 carbon atoms, and the macromonomer. The polyethylene composition has (D) a density of 0.890-0.980 g/cm3, (E) Mw=30,000-10,000,000, (F) Mw/Mn=2-30, (G) a long chain branch frequency of 0.01-3 per 1,000 C atoms, and (H) a shrinking factor (g? value) of 0.1-0.9 as measured by GPC/intrinsic-viscosity. The polyethylene composition can be finely divided particles having (P) a powder bulk density of 0.15-0.50 g/cm3.

Abstract: A liquid-phase process for polymerizing ?-olefins of the formula CH2?CHR, where R is H or an alkyl radical C1–C6, to produce a polymer that is soluble in the reaction medium, comprising the steps of: a) continuously polymerizing in liquid phase the ?-olefin in the presence of a catalyst system based on a transition metal compound; b) continuously withdrawing from step a) a solution of polymer in the liquid reaction medium; c) mixing in one or more mixing stages said solution of polymer in the reaction medium with an organic deactivator having: at least a hydroxy group, a boiling point higher than 150° C., and a ratio between the molecular weight (MW) and the number of hydroxy groups (OH) comprised between 20 and 100.

Abstract: Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

Abstract: A metallocene catalyst may be temporarily and reversibly passivated by contact with an effective amount of an unsaturated hydrocarbon passivating compound.

Abstract: A cyclic olefin having a specific polar group is polymerized by addition polymerization in a hydrocarbon solvent, using a polymerization catalyst component containing (i) a specific transition metal compound, (ii) a Lewis acid compound and (iii) an alkyl aluminoxane, or the cyclic olefin is polymerized by addition polymerization in the hydrocarbon solvent, using the polymerization catalyst component, by further adding at least one aromatic vinyl compound and at least one cyclic nonconjugated polyene compound, or either one of them as a molecular weight modifier, thereby obtaining a cyclic olefinic addition polymer.

Abstract: A process is disclosed for producing an acidic superabsorbent polysaccharide derivative, comprising the steps of: (a) crosslinking at least one polysaccharide containing acidic groups, such as carboxymethyl cellulose and/or 6-carboxy starch, with a crosslinking agent to produce a gel; (b) if necessary, adjusting the pH of the polysaccharide to a value between 3.5 and 5.5; (c) comminuting the acidified polysaccharide gel; and (d) drying the comminuted polysaccharide at elevated temperature. The superabsorbent polysaccharide obtainable by this process has a pH below 5 and provides odour control when contacted with malodorous fluids.

Abstract: The use of two or more light solvent boiling pool reactors in series allows polymerization of ethylene and comonomer(s) to cost effectively produce bimodal polyethylene copolymers having lower densities than are practically achievable with conventional stirred tank, slurry loop or gas phase reactor technologies. Introducing catalyst to only the first reactor, operating the first reactor at high hydrogen compositions, and using a plurality of series-connected flash drums to remove hydrogen from the first reactor polymer slurry product stream allows for the production of highly homogeneous high molecular weight bimodal polyethylene resins.

Abstract: The invention provides for polymerization catalyst compositions, and for methods for introducing the catalyst compositions into a polymerization reactor. More particularly, the method combines a catalyst component containing slurry and a catalyst component containing solution to form the completed catalyst composition for introduction into the polymerization reactor. The invention is also directed to methods of preparing the catalyst component slurry, the catalyst component solution and the catalyst compositions, to methods of controlling the properties of polymer products utilizing the catalyst compositions, and to polymers produced therefrom.

Abstract: A novel continuous gas phase polymerization process for producing polyethylene and interpolymers of ethylene and at least one other olefin is provided wherein a non-aromatic halogenated hydrocarbon is used in a specified amount such that the activity of the titanium, zirconium and/or hafnium containing Ziegler-Natta catalyst is increased.

Abstract: A novel continuous gas phase polymerization process for producing polyethylene and interpolymers of ethylene and at least one other olefin is provided wherein a saturated halogenated hydrocarbon is used in a specified amount such that the activity of the titanium containing Ziegler-Natta catalyst is increased.

Abstract: A novel continuous gas phase polymerization process for producing polyethylene and interpolymers of ethylene and at least one other olefin is provided wherein chloroform is used in a specified amount such that the activity of the titanium containing Ziegler-Natta catalyst is increased.

Abstract: Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

Abstract: A drag-reducing polymer capable of dissolving even in cold fluids is described, along with a method for manufacturing said drag-reducing polymer. The drag-reducing polymer has at least one alpha-olefin monomer with between a four and nine carbon chain length and a co-monomer and has less than 25% monomers (molar content) with carbon chain lengths of 12 or longer. A drag-reducing polymer suspension is also described.

Abstract: A polymerization system for ring opening polymerization of cycloolefins, comprising a catalyst [MoOX2L2], a Lewis acid as co-catalyst, and a chain-transfer agent, wherein (1) both X groups are the same halogen atom selected from the group consisting of Cl and Br, and both L groups are the same halogen atom as X; or (2) both of the X groups are the same halogen atom selected from the group consisting of Cl and Br, and both of the L groups are the same straight chain or branched alkyl group having 1-4 carbon atoms; or (3) both X groups are the same halogen atom selected from the group consisting of Cl and Br, and both L groups are the same straight chain or branched alkoxy group having 1-4 carbon atoms; or (4) both X groups are the same alkyl group having 1-4 carbon atoms, and both L groups are the same alkoxy group having 1-4 carbon atoms; or (5) one X group is a halogen atom selected from the group consisting of Cl and Br, and the other X group together with both L groups cons

Abstract: The present invention concerns a method for the copolymerization of conjugated diolefins and vinyl-aromatic monomers in the presence of rare-earth catalysts and the use of the copolymers in rubber mixtures for tire applications.

Abstract: Disclosed is for the preparation of a catalytic composition for the polymerization of alpha-olefins. The catalyst comprises a compound of a transition metal (i) of Groups 4 to 6 of the Periodic Table, containing at least one possibly substituted cyclopentadiene ligand, and an activator (ii) chosen from aluminoxanes and ionizing agents supported on a support (iii) consisting of porous particles of polyolefin(s). Preparation includes a preliminary polymerization which includes contact with an alpha-olefin, under polymerizing conditions, in a diluent whose kinematic viscosity, measured at 20° C., is from 3 to 3000 cSt (centistokes) from 3 to 3000 mm2/s, such as mineral oil which may be derived from coal tars and petroleum fractions, to form from 0.01 to 50 g of polyolefin per g of catalyst containing compounds (i), (ii) and (iii).

Abstract: This invention relates to a process for the production of polydienes having controlled Mooney viscosity, carried out by means of catalysts based on rare earth compounds, which is characterized in that the conjugated dienes used are polymerized in the presence of from 0.005 to 80 wt. % of 1,2-dienes, based on the sum of conjugated dienes used and of 1,2-dienes used. The polydienes thus produced are used particularly in the manufacture of car tires.

Abstract: A process for homo or copolymerizing propylene, wherein propylene is polymerized in the presence of a catalyst at an elevated temperature in a reaction medium, in which a major part is formed by propylene. The polymerization is carried in at least one slurry reactor in the presence of liquid propylene at a temperature between 80° C. and the critical temperature of the reaction medium and a catalyst system producing within said temperature range a high productivity and essentially constant isotacticity within wide melt index range.

Abstract: Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

Abstract: This invention relates to a composition of matter represented by the formula below, and to a polymerization process comprising combining an olefin in the gas or slurry phase with an activator, a support and a compound represented by the following formula: wherein M is a group 3 to 14 metal, each X is independently an anionic leaving group, n is the oxidation state of M, m is the formal charge of the YZL ligand, Y is a group 15 element, Z is a group 15 element, L is a group 15 or 16 element, R1 and R2 are independently a C1 to C20 hydrocarbon group, a heteroatom containing group, silicon, germanium, tin, lead, phosphorus, a halogen, R1 and R2 may also be interconnected to each other, R3 is absent, or is hydrogen, a group 14 atom containing group, a halogen, a heteroatom containing group, R4 and R5 are independently an aryl group, a substituted aryl group, a cyclic alkyl group, a substituted cyclic alkyl group, or multiple ring system, R6 and R7 are independently absent or hydrogen

Abstract: A novel process for producing homopolymers and copolymers of ethylene which involves contacting ethylene and/or ethylene and at least one or more olefin comonomer(s) under polymerization conditions with a Ziegler-Natta type catalyst substantially free of internal electron donor, trimethylaluminum and at least one compound containing at least one carbon-oxygen-carbon linkage (C—O—C) of the formula R1—O(—R2—O)n—R3 where n ranges from 0 to 30, and R1, R2 and R3 independently contain from 1 to 30 carbon atoms and from 0 to 30 heteroatoms of an element, or mixtures thereof, selected from Groups 13, 14, 15, 16 and 17 of the Periodic Table of Elements, and further wherein R1, R2 and/or R3 can be linked and form part of a cyclic or polycyclic structure. Also provided are films and articles produced therefrom.

Abstract: Crystalline polymers of ethylene, propylene or cyclic olefins or mixtures thereof are prepared by a process in which polymerization is carried out in the presence of a metallocene catalyst system in a dispersion.

Abstract: A novel loop/slurry olefin polymerization process is provided which produces ultra high molecular weight ethylene homopolymer.

Abstract: Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

Abstract: By utilizing the vapor phase polymerization techniques of the present invention, numerous distinct and highly beneficial advantages are realized. For instance, cis-1,4-polyisoprene rubber and high cis-1,4-polybutadiene rubber having a consistent and controllable molecular weight can be easily and practically prepared without utilizing a solvent. The subject invention more specifically discloses a method for vapor phase polymerizing isoprene into cis-1,4-polyisoprene in a process comprising the steps of:(1) charging into a reaction zone said isoprene and a preformed catalyst system which is made by reacting an organoaluminum compound with titanium tetrachloride, preferably in the presence of at least one ether; wherein the isoprene is maintained in the vapor phase in said reaction zone by a suitable combination of temperature and pressure;(2) allowing said isoprene to polymerize into cis-1,4-polyisoprene in said reaction zone at a temperature within the range of about 0.degree. C. to about 100.degree. C.

Abstract: It has been determined that 1,3-butadiene monomer can be polymerized into cis-l,4-polybutadiene rubber utilizing a cobalt-based catalyst system which is comprised of (a) an organocobalt compound, (b) a trialkylaluminum compound and (c) hexafluoro-2-propanol. The use of this catalyst system results in extremely fast rates of polymerization. The molecular weight of the cis-1,4- polybutadiene rubber made utilizing this cobalt-based catalyst system can be regulated by conducting the polymerization in the presence of 1,5-cyclooctadiene. This present invention more specifically discloses a catalyst system which is particularly useful for polymerizing 1,3-butadiene monomer into cis-1,4-polybutadiene, said catalyst system being comprised of (a) an organocobalt compound, (b) a trialkylaluminum compound and (c) hexafluoro-2-propanol.

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 is disclosed a process for the regulation of the molecular weight of a high-cis 1,4-polybutadiene prepared by polymerizing 1,3-butadiene in a solution of an aliphatic and/or cycloaliphatic or aromatic solvent system employing as a catalyst system a mixture of (1) an organonickel compound, (2) an organoaluminum compound, and (3) a fluorine containing compound selected from the group consisting of hydrogen fluoride and hydrogen fluoride complexes which are prepared by complexing hydrogen fluoride with a ketone, an aldehyde, a nitrile, a mineral acid containing oxygen, an ester, an ether, an alcohol, a phenol or water; said polymerization being conducted in the presence of small amounts of olefins selected from the group consisting of 1-butene, isobutylene, cis and trans-2-butene and allene.

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 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: By utilizing the vapor phase polymerization techniques of the present invention, numerous distinct and highly beneficial advantages are realized. For instance, cis-1,4-polyisoprene rubber and high cis-1,4-polybutadiene rubber having a consistent and controllable molecular weight can be easily and practically prepared without utilizing a solvent. The subject invention more specifically discloses a method for vapor phase polymerizing isoprene into cis-1,4-polyisoprene in a process comprising the steps of:(1) charging into a reaction zone said isoprene and a preformed catalyst system which is made by reacting an organoaluminum compound with titanium tetrachloride, preferably in the presence of at least one ether; wherein the isoprene is maintained in the vapor phase in said reaction zone by a suitable combination of temperature and pressure;(2) allowing said isoprene to polymerize into cis-1,4-polyisoprene at a temperature within the range of about 35.degree. C. to about 70.degree. C.

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 is provided a process for producing a cyclic olefin copolymer by copolymerizing (A) ethylene and (B) a particular cyclic olefin in the presence of (C) a metallocene catalyst and (D) a small amount of an .alpha.-olefin having 3 to 20 carbon atoms. According to the said process, said copolymer can be produced at a high activity and its molecular weight can be controlled in a wide range. The copolymer produced by the said process has excellent properties inherent to the cyclic olefin copolymer.

Abstract: Low density ethylene copolymers are obtainable by adding an aromatic hydrocarbon solution of a catalyst system, containing, as active components, metallocene complexes of metals of subgroups IV and V of the Periodic Table and oligomeric alumina compounds, to a mixture containing ethylene, comonomers and aliphatic hydrocarbons.

Abstract: A method for preparing a propylene (co)polymer having a substantially high syndiotactic structure and a desired molecular weight which comprises the step of (co)polymerizing propylene or propylene and a small amount of another olefin by the use of a transition metal compound catalyst having asymmetric ligands in the presence of a specific internal olefin.

Abstract: A polyethylene, having 1 to 60 methyl branches and 1 to 60 hexyl or higher branches per 1000 carbon atoms, a g-value of 0.5 to 0.8, and a limiting viscosity [.eta.] of 0.005 to 20.0 dl/g as measured at 140.degree. C. in o-dichlorobenzene, and a method for producing the same by polymerizing ethylene using a catalyst system comprising a coordination nickel compound of zero- or two-valent nickel and an aminobis(imino)phosphorane represented by a general formula (I): ##STR1## where R.sub.1, R.sub.2, R.sub.3 and R.sub.4 may be the same as or different from each other and are respectively n-alkyl, isoalkyl, aryl or trialkylsilyl, in the presence of .alpha.-olefin.

Abstract: Suspensions, in oils, of particles containing a transition metal compound, which are spheroidal and of narrow particle size distribution.These suspensions can be employed in processes for the polymerization of alpha-olefins, carried out in the presence of an organoaluminium activator.

Abstract: In a transition metal catalyst system, the improvement comprising including in the catalyst system an autoacceleration inhibitor, which (i) at about the temperature at which the catalyst system autoaccelerates, decomposes into a poison for the catalyst system; (ii) is present in the catalyst system in an amount sufficient to provide the quantity of poison required to inhibit the autoacceleration of the catalyst system at the autoacceleration temperature; and (iii) is either essentially inert at the normal operating temperature of the catalyst system or will cause substantially less inhibition of the catalyst system at the normal operating temperature than at the autoacceleration temperature.

Abstract: A process for producing a high density polyethylene resin which has a negligible n-paraffin content while having a melt index ratio of at least 75 by polymerizing ethylene with a minor amount of a diene in the presence of a supported organophosphorous modified vanadium-containing catalyst component. Vanadium-containing catalyst components useful with an organoaluminum cocatalyst for polymerizing ethylene with an aliphatic diene to produce high density resins having not only a low C.sub.10 -C.sub.32 n-paraffin content (characteristic of high molecular weight polymers having a narrow molecular weight distribution), but, surprisingly, also a melt index ratio desirable for melt blowing applications more characteristic of vanadium catalyzed polymers (which have relatively high n-paraffin content), are obtained by contacting an inert support material with an organoaluminum compound, an optional halogenating agent, a vanadium compound, and an organophosphorous compound.

Abstract: The present invention relates to an alpha-olefin prepolymer catalytically active in an alpha-olefin (co-)polymerization comprising a transition metal, an organometallic compound and an antistatic agent. The prepolymer can be prepared by contacting the antistatic agent with a catalyst comprising the transition metal and the organometallic compound before or during an alpha-olefin prepolymerization. It can also be prepared by contacting the antistatic agent with an alpha-olefin prepolymer after a prepolymerization. It can also be prepared by a combination of the two methods. The prepolymer can be introduced into a gas phase (co-)polymerization medium for preparing polyolefin directly in a dry powder form, with a reduced amount of sheeting and agglomerates.

Abstract: Pure syndiotactic 1,2-polybutadiene is a thermoplastic resin which has double bonds attached in an alternating fashion to its polymeric backbone. Films, fibers and molded articles can be made utilizing syndiotactic 1,2-polybutadiene. It can also be blended into rubbers and cocured therewith. Syndiotactic 1,2-polybutadiene can be made by solution, emulsion or suspension polymerization. It typically has a melting point which is within the range of about 195.degree. C. to about 215.degree. C. However, it is often desirable for the syndiotactic 1,2-polybutadiene to have a melting point of less than about 195.degree. C. This invention discloses a process for preparing syndiotactic 1,2-polybutadiene having a melting point of less than about 195.degree. C.

Abstract: A process for the polymerization of olefins in the presence of hydrogen comprising contacting the olefin, a cyclopentadienyl compound and a catalyst comprising a transition metal compound at polymerization conditions.

Abstract: A process for preparing a polymerization catalyst useful for the polymerization of olefins is provided comprising contacting a metal dihalide compound wherein the metal is selected from Group 2 and Group 12 of the Periodic Table and a transition metal compound which is a hydrocarbyloxide of a transition metal selected from Group 4 and Group 5 to form a first catalyst component; contacting the first catalyst component with at least one organoaluminum precipitating agent, wherein at least at the commencement of this step, the temperature at which such contacting is carried out is greater than about 70.degree. C. to about 150.degree. C. to form a solid product, and contacting the solid product with an activating agent to form a catalyst. Other aspects of the invention provide a catalyst prepared by the above described method and a polymerization process employing the thus prepared catalyst.

Abstract: A method for producing a stereospecific polyolefin in the presence of a catalyst comprising a transition metal compound and an organometallic compound, wherein a catalyst system is used which comprises: (A) a solid catalyst component prepared by reacting a homogeneous solution containing (i-1) magnesium and a hydroxylated organic compound, (i-2) an oxygen-containing organic compound of titanium and/or (i-3) an oxygen-containing organic compound of silicon and an oxygen-containing organic compound of aluminum and/or a boron compound, with (ii) at least one aluminum halide compound to obtain a solid product, and further reacting to this solid product (iii) an electron-donative compound, (iv) a titanium halide compound, and (v) ethylene and/or an .alpha.-olefin having at least 3 carbon atoms, (B) at least one member selected from the group consisting of organometallic compounds of Groups IA, IIA, IIB, IIIB and IVB of the Periodic Table, and (C) an electron-donative compound.

Abstract: A method of producing a polyolefin, which comprises polymerizing at least one olefin in the presence of a catalyst system comprising(A) a catalyst component prepared by bringing ethylene and/or an .alpha.-olefin in contact with a solid composite obtained by reacting a reaction product, which has been produced by reacting a uniform solution containing(i) at least one member selected from the group consisting of metal magnesium and hydroxylated organic compound, and oxygen-containing organic compounds of magnesium and(ii) at least one oxygen-containing organic compound of titanium with(iii) at least one organoaluminum compound and/or(iv) at least one silicon compound, with(v) at least one aluminum halide compound, thereby allowing the ethylene and/or the .alpha.-olefin to be absorbed into the solid composite, and(B) at least one catalyst component selected from the group consisting of organometallic compounds of metals of Groups Ia, IIa, IIb, IIIb and IVb of the Periodic Table.