Abstract: Amphiphilic Group VIII metathesis catalysts, as can be used in a range of polymerization reactions and other chemical methodologies.

Abstract: An organometallic compound obtainable by contacting: a compound having the following formula (I), wherein: Ra is a hydrocarbon radical; Rb, Rc and Rd, are hydrogen atoms, halogen atoms, or hydrocarbon radicals; with a Lewis acid of formula (II) MtR13 (II) wherein Mt is a metal belonging to Group 13 of the Periodic Table of the Elements; R1 are selected from the group consisting of halogen atoms, halogenated C6–C20 aryl and halogenated C7–C20 alkylaryl groups

Abstract: A process for producing a polar olefin copolymer comprises copolymerizing a non-polar olefin and a polar olefin in the presence of a transition metal compound selected from Groups 4, 5, 6 and 11 of the periodic table, which is represented by the following formula (IV): wherein M? is a transition metal atom selected from Groups 4, 5, 6 and 11 of the periodic table, m is an integer of 1 to 6, A is —O—, —Si—, —Se—, —N(R6)—, n is a number satisfying a valence of M?, R1 to R4 and R6 are each a hydrogen atom, a halogen atom, a hydrocarbon group and the like, and X is a halogen atom, an oxygen atom, a hydrocarbon group and the like, and at least one compound (B) selected from the group consisting of an organometallic compound (B-1), an organoaluminum oxy-compound (B-2) and an ionic ionizing compound (B-3). Therefore, the process is capable of obtaining a polar olefin copolymer having excellent properties under mild polymerization conditions.

Abstract: The present invention relates to a catalyst composition and a method for making the catalyst composition of a polymerization catalyst and a static charge modifier. The invention is also directed to the use of the catalyst composition in the polymerization of olefin(s). In particular, the polymerization catalyst system is supported on a carrier. More particularly, the polymerization catalyst comprises a bulky ligand metallocene-type catalyst system.

Abstract: This invention relates to a process for producing a polymeric product by the polymerisation of at least one olefinic compound in the form of an olefin or a compound including an olefinic moiety by contacting the at least one olefinic compound with a polymerisation catalyst. The catalyst comprises the combination of a source of a Group IV to VI transition metal; and a ligating compound of the formula (R1)mX1(Y)X2(R2)n. The process is characterised therein that when R1 and R2 are independently a hydrocarbyl group or a heterohydrocarbyl group which contains at least one non-polar substituent, the olefinic compound is contacted with the polymerisation catalyst at a reaction temperature from and above 70° C.; and where R1 and R2 are independently a hydrocarbyl group or a heterohydrocarbyl group which contains no substituent, the olefinic compound is contacted with the polymerisation catalyst at a reaction temperature from and above 90° C.

Abstract: The invention has an object to provide a catalyst for polymerizing or copolymerizing an ?-olefin, catalyst constituent thereof, and method of polymerizing ?-olefins with the catalyst, for production of ?-olefin polymers or copolymers with high hydrogen response, high polymarization reaction rate, high stereoregularity and excellent melt fluidity. The invention discloses a catalyst constituent of the catalyst for polymerizing or copolymerizing an ?-olefin, represented by Formula 37 or 38: Si(OR1)3(NR2R3)Formula 37 (where in Formula 37, R1 is a hydrocarbon group with 1 to 6 carbon atoms; R2 is a hydrocarbon group with 1 to 12 carbon atoms or hydrogen; and R3 is a hydrocarbon group with 1 to 12 carbon atoms) RNSi(OR1)3Formula 38 (where in Formula 38, R1 is a hydrocarbon group with 1 to 6 carbon atoms; and RN is a cyclicl amino group).

Abstract: Methods of controlling the flow index and/or molecular weight split of a polymer composition are disclosed. The method of producing a polymer composition in one embodiment comprises incorporating a high molecular weight polymer into a low molecular weight polymer to form the polymer composition in a single polymerization reactor in the presence of polymerizable monomers, a bimetallic catalyst composition and at least one control agent; wherein the control agent is added in an amount sufficient to control the level of incorporation of the high molecular weight polymer, the level of low molecular weight polymer, or both. Examples of control agents include alcohols, ethers, amines and oxygen.

Abstract: Ethylene propylene copolymers, substantially free of diene, are described. The copolymers will have a uniform distribution of both tacticity and comonomer between copolymer chains. Further, the copolymers will exhibit a statistically insignificant intramolecular difference of tacticity. The copolymers are made in the presence of a metallocene catalyst.

Abstract: This invention relates to supported activators comprising the product of the combination of an ion-exchange layered silicate, an organoaluminum compound, and a heterocyclic compound, which may be substituted or unsubstituted. This invention further relates to catalyst systems comprising catalyst compounds and such activators, as well as processes to polymerize unsaturated monomers using the supported activators. For the purposes of this patent specification and the claims thereto, the term “activator” is used interchangeably with the term “co-catalyst”, the term “catalyst” refers to a metal compound that when combined with an activator polymerizes olefins, and the term “catalyst system” refers to the combination of a catalyst and an activator with or without a support. The terms “support” or “carrier”, for purposes of this patent specification, are used interchangeably and are any ion-exchange layered silicates.

Abstract: Catalyst compositions that are highly tolerant of catalyst poisons for use in addition polymerizations comprising a catalytic derivative of a Group 4 metal complex, a cocatalyst, and a Group 13 metal amide compound.

Abstract: An ethylene-based polymer which is an ethylene/C4 to C10 ?-olefin copolymer and satisfies the following requirements [k1] to [k3]: [k1] melt flow rate (MFR) under a loading of 2.16 kg at 190° C. is in the range of 1.0 to 50 g/10 minutes; [k2] LNR defined as a scale of neck-in upon film molding is in the range of 0.6 to 1.4; and [k3] take-up speed at break [DS (m/min)] at 160° C. and melt flow rate (MFR) satisfy the following relationship (Eq-1): 12×MFR0.577?DS?165×MFR0.577 (Eq-1), and a thermoplastic resin composition containing the ethylene-based polymer, provide a molded product, preferably a film, excellent in moldability and mechanical strength.

Abstract: The invention relates to a process for the polymerization of olefins using an antistatic agent. In particular, the invention relates to a polymerization process to produce propylene polymers using a supported metallocene catalyst system and an antistatic agent. The antistatic agent may also be contacted with a scavenger prior to polymerization.

Abstract: A process for the preparation of an olefin polymerisation catalyst comprising: a) reacting an aluminoxane and a Lewis base in an optionally halogenated hydrocarbon solvent to form a particulate suspension; b) reacting said suspension with a metallocene complex in an optionally halogenated hydrocarbon solvent; and optionally c) isolating the olefin polymerisation catalyst.

Abstract: In one embodiment the invention is a polymerizable composition comprising a) an organoborane amine complex; b) one or more of monomers, oligomers or polymers having olefinic unsaturation which is capable of polymerization by free radical polymerization; c) one or more compounds, oligomers or prepolymers having a siloxane backbone and reactive moieties capable of polymerization; and d) a catalyst for the polymerization of the one or more compounds, oligomers or prepolymers having a siloxane backbone and reactive moieties capable of polymerization. This composition may further comprise a compound which causes the organoborane amine complex to disassociate.

Abstract: This invention is based upon the discovery that a catalyst system which is comprised of (a) palladium or a palladium compound and (b) a fluorinated alcohol is effective for polymerizing norbornene-functional monomers into polynorbornene-functional polymers. It has been further discovered that this catalyst system is more effective in polymerizing certain norbornene-functional monomers that are difficult to polymerize, such as norbornene ester monomers, than prior art catalyst systems. The activity of the catalyst systems of this invention can be further improved with respect to polymerizing some monomers by including a Lewis acid and/or a ligand, such as a phosphine or a carbene, in the system. In any case, the catalyst systems of this invention offer the advantage of being soluble in a wide variety of solvents, relatively inexpensive, and capable of polymerizing many norbornene-functional monomers that are difficult to polymerize with conventional catalyst systems.

Abstract: A catalyst system useful for polymerizing olefins is disclosed. The catalyst system comprises a cocatalyst and a supported transition metal prepared from a halogen-containing Group 4–6 transition metal compound and an organoaluminum-siloxane containing mixture. The latter mixture, which is prepared from an organoaluminum compound and an organomagnesium-siloxane reaction product, incorporates a chelating ligand. The invention includes a method for making the catalyst system and a process for polymerizing olefins using the catalyst system. The process is convenient and avoids expensive catalyst components used in known olefin polymerization processes.

Abstract: This invention is based upon the discovery that a catalyst system which is comprised of (a) palladium or a palladium compound and (b) a fluorinated alcohol is effective for polymerizing norbornene-functional monomers into polynorbornene-functional polymers. It has been further discovered that this catalyst system is more effective in polymerizing certain norbornene-functional monomers that are difficult to polymerize, such as norbornene ester monomers, than prior art catalyst systems. The activity of the catalyst systems of this invention can be further improved with respect to polymerizing some monomers by including a Lewis acid and/or a ligand, such as a phosphine or a carbene, in the system. In any case, the catalyst systems of this invention offer the advantage of being soluble in a wide variety of solvents, relatively inexpensive, and capable of polymerizing many norbornene-functional monomers that are difficult to polymerize with conventional catalyst systems.

Abstract: The invention relates to a chemical compound of formula (I), wherein M1 represents an element selected from main groups II, III or IV of the periodic table of elements; x is equal to 1, 2, 3 or 4; y is equal to 2, 3 or 4, and; A represents a cation of main group V of the periodic table of elements; R1 is the same or different and represents a branched or unbranched linear or cyclic C1–C40 group that contains carbon; R2 is the same or different and represents a branched or unbranched linear or cyclic C1–C40 group that contains carbon; R3 represents a branched or unbranched linear or cyclic C1–C40 group that contains carbon, and; R4 represents a hydrogen atom; whereby R2 and R3 are always different from one another

Abstract: An organometallic composition which can be used as activating component in a metallocene catalyst for the (co)polymerization of ?-olefins, comprises: (A) a fluorinated di-unsaturated cyclic compound, having a relatively acid hydrogen atom, (B) an organometallic compound sufficiently basic to react with the acid hydrogen of the above compound (A), and (C) a polar aprotic organic compound, not containing metallic atoms, having a dielectric constant, in the pure state, equal to or greater than 2, and a weak coordinating capacity. Said composition allows a metallocene catalytic system of the ionic type to be obtained, with a high activity in the (co)polymerization of olefins and a reduced content of metallic residue in the polymeric product thus obtained.

Abstract: This invention is based upon the unexpected discovery that alkylated diphenylamines can be used in conjunction with nickel based catalyst systems which contain (a) an organonickel compound, (b) an organoaluminum compound, and (c) a fluorine containing compound to produce cis-1,4-polybutadiene having reduced molecular weight and an increased level of branching. This results in the cis-1,4-polybutadiene exhibiting good processability without sacrificing cold flow characteristics. Additionally, the alkylated diphenylamine which remains in the rubber acts in a manner which provides it with antioxidant protection. In other words, the use of alkylated diphenylamines accomplishes the three major objectives that are realized by employing para-styrenated diphenylamines (reduced molecular weight, regulated polymer macrostructure through branching and antidegradant protection).

Abstract: Polymeric supports, which have been treated with a halosulfonic acid, increase the activity of single-site catalysts used with aluminoxane co-catalysts, resulting in improved ethylene polymerization. The present invention seeks to provide polymeric catalyst supports which have been treated with halosulfonic acid for improved activity.

Abstract: A process for producing a polar olefin copolymer comprises copolymerizing a non-polar olefin and a polar olefin in the presence of a transition metal compound selected from Groups 4, 5, 6 and 11 of the periodic table, which is represented by the following formula (IV): wherein M? is a transition metal atom selected from Groups 4, 5, 6 and 11 of the periodic table, m is an integer of 1 to 6, A is —O—, —Si—, —Se—, —N(R6)—, n is a number satisfying a valence of M?, R1 to R4 and R6 are each a hydrogen atom, a halogen atom, a hydrocarbon group and the like, and X is a halogen atom, an oxygen atom, a hydrocarbon group and the like, and at least one compound (B) selected from the group consisting of an organometallic compound (B-1), an organoaluminum oxy-compound (B-2) and an ionic ionizing compound (B-3). Therefore, the process is capable of obtaining a polar olefin copolymer having excellent properties under mild polymerization conditions.

Abstract: This invention relates to the polymerization of vinylically-unsaturated monomers in the presence of a chain transfer catalysts where the polymerization process is initiated with hydrogen gas or a hydrogen atom donor rather than conventional free radical initiators. This invention further relates to an improved process for the polymerization of vinylically-unsaturated monomers in the presence of a chain transfer catalysts where the polymerization process is initiated with hydrogen gas.

Abstract: The present invention relates to a catalyst composition and a method for making the catalyst composition which comprises a polymerization catalyst and at least one gelling agent. The invention is also directed to the use of the catalyst composition in the polymerization of olefin(s). In particular, the polymerization catalyst system is supported on a carrier.

Abstract: The present invention provides a method for producing homo- and co-polymers of ethylene, or more particularly a method for producing homo- and co-polymers of ethylene in the presence of (a) a solid titanium catalyst produced by preparing a magnesium solution by contact-reacting a halogenated magnesium compound with an alcohol; reacting thereto an ester compound having at least one hydroxyl group and a silicon compound having at least one alkoxy group; and adding a mixture of a titanium compound and a silicon compound; (b) organometallic compounds of Group II or III of the Periodic Table; and (c) a cyclic nitrogen compound. The catalyst for homo- and co-polymerization of ethylene, produced according to the present invention, exhibits high activity, and the polymers produced by the method of the present invention by using said catalyst have the advantages of exhibiting high bulk densities and narrow molecular weight distributions.

Abstract: A catalyst system comprising at least one metallocene, at least one cocatalyst, at least one support material and, if desired, further organometallic compounds is described. The catalyst system can advantageously be used for the polymerization of olefins and displays a high catalyst activity and gives a good polymer morphology without it being necessary to use aluminoxanes such as methylaluminoxane (MAO), which usually has to be used in high excess, as cocatalyst.

Abstract: A catalyst composition for use in dimerizing, co-dimerizing or oligomerizing olefins comprises: at least one zero-valent nickel complex; at least one acid with formula H+X? in which X? represents an anion; and at least one ionic liquid with general formula Q+ A? in which A? is an anion identical to or different from X?. The composition can also comprise a nitrogen-containing ligand. It can be used in dimerizing, co-dimerizing, oligomerizing and in polymerizing olefins.

Abstract: A crosslinked polymer (A) which comprises, as essential structural units, units derived from (a) one or more vinyl monomers selected from the group consisting of water-soluble vinyl monomers and/or vinyl monomers which become water-soluble upon hydrolysis and units derived from (b) a crosslinking agent and which satisfies the following requirements: (1): (X)?25 g/g, (2): (Y)?15 g/g, and (3): (Y)??0.54 (X)+41. It has exceedingly high water retentivity and exceedingly high absorbing power under load. When applied to an absorbent structure and an absorbent article, the polymer has excellent absorbing performance. In the relationships, (X) is the amount of physiological saline retained through 1-hour absorption and (Y) is the amount of physiological saline absorbed through 1-hour standing under a load of 60 g/cm2.

Abstract: A process for polymerizing unsaturated monomers is disclosed. The process comprises polymerizing, in the presence of a late transition metal catalyst (LTMC), a variety of unsaturated monomers which are traditionally, some of which are exclusively, made by free radical polymerizations. The LTMC polymerization provides the polymer with improved properties such as no free radical residue and narrow molecular weight distribution.

Abstract: An olefin polymerization catalyst is described which includes: (A) a solid catalyst component being prepared by copulverizing a magnesium compound, an aluminum compound, an electron donor and a titanium compound, and (B) an organoaluminum compound. The present invention is also directed to a process for preparing polyolefins using the aforesaid catalyst system to polymerize olefins.

Abstract: The present invention relates to vanadium-imido-phosphoraneiminato compounds, to compositions containing vanadium-imido-phosphoraneiminato compounds, which compositions are suitable especially as catalysts for the polymerization of olefins, especially for ethylene/propylene or ethylene/?-olefin copolymerization and the terpolymerization of those monomers with dienes.

Abstract: A process for making olefin-acrylic copolymers is disclosed. The process comprises polymerizing an olefin and an acrylic monomer in the presence of an activator and a Group 8-10 late transition metal complex. The late transition metal catalyst contains an isoindoline ligand.

Abstract: A catalyst system for the polymerization of olefins comprising the product obtained by contacting: (A) at least one transition metal organometallic compound, pyrrolidyl bis(?-cyclopentadienyl)methylzirconium being excluded, and (B) an organometallic compound obtained by contacting: a) a Lewis base having formula (I): ?wherein Ra, Rb, Rc and Rd, equal to or different from each other, are selected from the group consisting of hydrogen, halogen, linear or branched, saturated or unsaturated, C1-C10 alkyl, C6-C20 aryl, C7-C20 arylalkyl and C7-C20 alkylaryl groups; with b) a Lewis acid of formula (II) MtR13??(II) ?wherein Mt is a metal belonging to Group 13 of the Periodic Table of th Elements; R1, equal to or different from each other, are selected from the group consisting of halogen, halogenated C6-C20 aryl and halogenated C7-C20 alkylaryl groups; and (C) optionally an alkylating agent.

Abstract: Catalyst systems useful for olefin polymerization are disclosed. The catalysts include a bimetallic complex that incorporates two linked indenoindolyl groups, each of which is pi-bonded through its cyclopentadienyl ring to one of the metals. Compared with conventional indenoindolyl complexes, the bimetallic complexes of the invention have enhanced ability to give polyolefins with desirably low melt indices. Certain bimetallic indenoindolyl complexes also provide a way to broaden polymer molecular weight distribution and thereby improve processability simply by regulating the amounts of comonomer and activator used in the polymerization.

Abstract: Methods of controlling rheological properties of polymer compositions comprising at least one high molecular weight polymer and one low molecular weight polymer are disclosed. The polymer compositions are produced by polymerizing monomers in a single reactor using a bimetallic catalyst composition. A control agent such as, for example, an alcohol, ether, oxygen or amine is added to the reactor to control the rheological properties of the reactor. The polymerization takes place in the presence of rheological-altering compounds such as alkanes and aluminum alkyls. The control agents are added in an amount sufficient to counter the influences of the rheological-altering compounds.

Abstract: In one embodiment the invention is a polymerizable composition comprising a) an organoborane amine complex; b) one or more of monomers, oligomers or polymers having olefinic unsaturation which is capable of polymerization by free radical polymerization; c) one or more compounds, oligomers or prepolymers having a siloxane backbone and reactive moieties capable of polymerization; and d) a catalyst for the polymerization of the one or more compounds, oligomers or prepolymers having a siloxane backbone and reactive moieties capable of polymerization. This composition may further comprise a compound which causes the organoborane amine complex to disassociate.

Abstract: In one embodiment the invention is a polymerizable composition comprising a) an organoborane amine complex; b) one or more of monomers, oligomers or polymers having olefinic unsaturation which is capable of polymerization by free radical polymerization; c) one or more compounds, oligomers or prepolymers having a siloxane backbone and reactive moieties capable of polymerization; and d) a catalyst for the polymerization of the one or more compounds, oligomers or prepolymers having a siloxane backbone and reactive moieties capable of polymerization. This composition may further comprise a compound which causes the organoborane amine complex to disassociate.

Abstract: A process for preparing premixed supported boraaryl catalysts having improved shelf life is provided. The process comprises supporting an organometallic compound comprising a group 3-10 transition metal or lanthanide metal and at least one boraaryl ligand an inorganic support which has been chemically and thermally dehydroxylated to remove all hydroxyl from the surface of the support; contacting with an organoaluminum compound utilizing an incipient wetness procedure wherein 90 to 150 percent of the catalyst pore volume is filled with a hydrocarbon solution containing the organoaluminum and provide a molar ratio of aluminum to transition/lanthanide metal of 0.5:1 to 50:1; and recovering the premixed catalyst powder.

Abstract: Catalysts useful for polymerizing olefins are disclosed. The catalysts comprise an activator and a triple-decker bimetallic complex. The complex includes two Group 3-10 transition metals and a delocalized dianionic ligand that is pi-bonded to each of the metals. The behavior of the catalysts can be modified by choice of each metal, by the choice of the dianionic ligand, or by choice of the ancillary ligands. The invention provides a new way to make a large variety of catalyst systems.

Abstract: The invention discloses a process for the preparation of polymeric absorbents useful for gelling organic liquids. The process comprises mixing one or more monomers with a cross-linking agent, a free radical initiator, an optional solvent, optionally in the presence of a transition metal source and subjecting the mixture so obtained to a conventional polymerisation method. The polymer is removed, crushed to obtain polymer powder, washed with solvent and dried by conventional methods to remove unreacted monomers, followed by swelling in alcohols to obtain the desired product.

Abstract: In one embodiment the invention is a polymerizable composition comprising a) an organoborane amine complex; b) one or more of monomers, oligomers or polymers having olefinic unsaturation which is capable of polymerization by free radical polymerization; c) one or more compounds, oligomers or prepolymers having a siloxane backbone and reactive moieties capable of polymerization; and d) a catalyst for the polymerization of the one or more compounds, oligomers or prepolymers having a siloxane backbone and reactive moieties capable of polymerization. This composition may further comprise a compound which causes the organoborane amine complex to disassociate.

Abstract: Provided are an aluminium-oxy compound obtained through reaction of an organoaluminium compound with water, which is soluble in hydrocarbon solvents and in which the amount of the organoaluminium compound remaining is at most 10% by weight; a carrier comprising the aluminium-oxy compound and an inorganic compound; and a catalyst component for olefin polymerization comprising the carrier and a transition metal compound. The catalyst component for olefin polymer production comprises the aluminium-oxy compound and gives polyolefins with good polymer morphology.

Abstract: The present invention relates to a process for the radical polymerization or copolymerization of ethylene under high pressure in the presence of at least one polymerization initiating-controlling compound capable of providing, by decomposition under the polymerization or copolymerization conditions: at least one initiating free radical (Z) which carries at least one site for initiating the (co)polymerization; and at least one stable free radical (SFR) which carries at least one site exhibiting the stable radical state and which is stable under the polymerization conditions, with, in total, as many initiating sites as sites exhibiting the stable radical state.

Abstract: A catalyst system useful for polymerizing olefins is disclosed. It comprises an activator and an organometallic complex. The complex includes a Group 3-10 transition or lanthanide metal and a 1,3-bis(arylimino)isoindoline or 1,3-bis(heteroarylimino)isoindoline ligand. Activities of the Group 8-10 catalyst systems rival or exceed those of late transition metal bis(imines). The resulting polyolefins typically have high molecular weights, broad molecular weight distributions, and a high degree of crystallinity, which makes them valuable for film applications.

Abstract: Polyethylene is formed by contacting ethylene with a novel iron or cobalt complex of a selected 1,4,7-triaza-3-oxa-1,4,6-heptatriene or 2,5,8-triaza-1,8-nonadiene, optionally in the presence of a cocatalyst such as an alkylaluminum compound. The polymers formed as useful for molding and in films.

Abstract: Substituted cyclopentenes, such as alkyl cyclopentenes, are polymerized by selected &agr;-imine complexes of nickel and palladium. The polymers are useful as molding resins or elastomers. Also disclosed herein are novel catalysts for the polymerization of cyclopentenes to form novel higher melting homopolycyclopentenes.

Abstract: The present invention relates to a process for preparation of polyolefin/inorganic component nanocomposite by in-situ polymerization, in which, a clay is first organically modified and then silica or titanium dioxide nanometer particles are incorporated into the layers of crystal sheets of the clay by sol-gel method. And a metallocene catalyst is then loaded on the above-mentioned material and a finished catalyst is obtained. The said catalyst is used for in-situ polymerization of ethylene or propylene, and polyolefin/clay nanocomposite is finally obtained. The process for preparation of the catalyst according to the present invention is simple, and the mechanical properties of the nanocomposite are high. For example, the Young's modulus and the tensile strength thereof are in the ranges of 700-2600 Mpa, and 20-55 MPa respectively.

Abstract: A novel process for the polymerization of olefins is provided. The process involves contacting at least one olefin with a Ziegler-Natta type catalyst in the presence of a specified compound that results in the production of polymeric products having a narrower molecular weight distribution. Also provide is a process for narrowing the molecular weight distribution of a polyolefin comprising contacting an olefin, a Ziegler-Natta catalyst and a compound specified herein. Further provided are novel polyethylenes, and films and articles produced therefrom.

Abstract: A process for the gas-phase (co-)polymerization of olefins in a fluidized bed reactor using a chromium oxide catalyst. The polymerization is performed in the presence of a process aid additive.

Abstract: A catalyst which comprises a compound of a transition metal in Groups 8 to 10 of the Periodic Table having a nitrogenous tridentate ligand, a clay, clay minteral, or lamellar ion-exchanging compound, an organosilane compound, and organoaluminum compound, etc.; and a process for producing a polyolefin with the catalyst. The catalyst is highly active, does not adhere to reactor walls, and can give a polyolefin excellent in powder morphology. Consequently, a polyolefin (especially polyethylene) can be industrially advantageously produced.