Abstract: A process for producing a chromium-based catalyst for the production of polyethylene, the process comprising providing a silica support having a surface area of at least 380 m2/g and a pore volume of at least 1.5 ml/g; impregnating the silica support with a liquid including a source of aluminum ions and a source of phosphate ions; neutralizing the resultant impregnated support with a neutralizing agent to provide a pH greater than 7 for the resultant neutralized support whereby aluminum phosphate forms in pores of the silica support; and, at any stage in the method, impregnating the silica support with a chromium component.

Abstract: The olefin polymerization catalyst of the invention is formed from a Group IVB transition metal compound represented by the following formula (I) and an organoaluminum oxy-compound or a compound which reacts with the transition metal compound to form an ion pair.

Abstract: The present invention relates to components of catalysts for the polymerization of olefins comprising a metallocene compound and a magnesium halide which have particular values of porosity and surface area. In particular the components of the invention have surface area (BET) greater than about 50 m2/g, porosity (BET) greater than about 0.15 cm3/g and porosity (Hg) greater than 0.3 cm3/g, with the proviso that when the surface area is less than about 150 m2/g, the porosity (Hg) is less than about 1.5 cm3/g. The components of the invention are particularly suitable for the preparation of catalysts for the gas-phase polymerization of &agr;-olefins.

Abstract: Olefin polymerization comprising catalysts based on a metallocene, an alumoxane and a support are disclosed. The process for the preparation of a supported olefin ploymerization catalyst comprises: a) a metallocene/activator reaction product, a solvent capable of dissolving it, and a porous support are brought into mutual contact, and b) the solvent is removed, and wherein step a) is carried out so that the porous support is impregnated with a volume of the metallocene/activator reaction product and solvent, which does not exceed the total pore volume of the support.

Abstract: An ethylene-alpha-olefin copolymerization catalyst is prepared by impregnating a silica calcined at elevated temperature sequentially with an organomagnesium compound such as dialkylmagnesium compound, a silane compound which is free of hydroxyl groups, such as tetraethyl orthosilicate. A transition metal component such as titanium tetrachloride is then incorporated into the support. Unexpectedly, the calcination temperature of the silica used to prepare the catalyst precursors has a strong influence on polymer product properties. By increasing the calcination temperature of the silica from 600° to 700° C. or higher temperatures, a catalyst precursor when activated produced ethylene/1-hexene copolymers with narrower molecular weight distributions (MWD) as manifested by a decrease of resin MFR values of ˜3-4 units. Activation of this catalyst precursor with a trialkylaluminum compound results in a catalyst system which is effective for the production of ethylene copolymers.

Abstract: Metallocenes containing aryl-substituted indenyl derivatives as ligands, process for their preparation, and their use as catalysts.

Abstract: A catalyst component, adapted for use in the polymerization and copolymerization of ethylene, is formed by reaction of an organomagnesium compound with a metal oxide support to form a supported organomagnesium composition, reaction of the supported organomagnesium composition and a tetraalkyl silicate, contact of the resulting product with a chlorinating reagent, and treatment of the product from the previous step with liquid titanium halide.

Abstract: A Group 4 transition metal complex containing a boron or aluminum bridging group containing a nitrogen containing electron donating group, especially an amido group.

Abstract: The new metallocene catalysts according to the present invention are prepared by reacting a metallocene compound with a compound having at least two functional groups. The metallocene compound is a transition metal compound, which is coordinated with a main ligand such as cyclopentadienyl group, and an ancillary ligand. The functional groups in the compound are selected from the group consisting of a hydroxyl group, an alkyl or aryl magnesium halide, a thiol group, a primary amine group, a secondary amine group, a primary phosphorous group, a secondary phosphorous group, etc. The metallocene catalysts according to the present invention have a structure in which an ancillary ligand of a metallocene compound is bonded to the functional groups of a compound having at least two functional groups. A structure of the metallocene catalysts can be varied with the type of a metallocene compound and a compound having at least two functional groups, and the molar ratio of each reactant.

Abstract: A catalytic system with an increased activity for the (co)polymerization of alpha-olefins comprises a catalyst of the metallocene type, which is capable of polymerizing olefins without aluminoxane, and a weak coordinating compound, which, when used in a polymerization process, enables a higher productivity than an analogous process carried out with the metallocene type catalyst per se.

Abstract: Solid mixed oxides composition of formula (I):

Abstract: The present invention provides a new type of supported metallocene catalyst system. In one aspect of the invention, an inorganic oxide support, such as silica, is impregnated with a Group XIII element such as B, Al or GA. The support is then contacted with a liquid catalyst system prepared by combining in a liquid an organo aluminoxane and a metallocene having two cyclopetadienyl-type ligands selected from substituted or unsubstituted cyclopentadienyl, indenyl, benzoindenyl, tetrahdroindenyl, benzofluorenyl, octahydrofluorenyl, and fluorenyl ligands to form a supported metallocene catalyst system. In preferred embodiments the process further includes conducting prepolymerization of at least one olefin in the presence of the supported metallocene catalyst system to produce a prepolymerized metallocene catalyst system. The prepolymerized metallocene catalyst system prepared in this manner yields substantially increased activity for the polymerization of olefins.

Abstract: Activator solid support for metallocenes as catalysts in the polymerization of olefins, characterized in that it consists of a group of support particles for a solid catalytic component, which are formed from at least one porous mineral oxide, the said particles having been modified in order to carry, on the surface, aluminium and/or magnesium Lewis-acid sites of formula: functionalization agent having reacted with —OH radicals carried by the base particles of the support, the functionalization reaction having been followed by a fluorination reaction. Also disclosed is a catalytic system including a metallocene catalyst, which has optionally been subjected to a prealkylation treatment; a cocatalyst; and an activator solid support for metallocene, as defined above.

Abstract: Novel heterogeneous catalysts for the which hydrogenation of olefins and arenes with high conversion rates under ambient conditions and the polymerization of olefins have been developed. The catalysts are synthesized from Ziegler-type precatalysts by supporting them on sulfate-modified zirconia.

Abstract: The present invention relates to a process for preparing a filled polymer composite comprising from 1 to 98 percent by weight of an interpolymer and from 2 to 99 percent by weight of a filler, said process comprising copolymerization in the presence of a cyclopentadienyl-containing transition metal catalyst and a filler, said filler having immobilized thereon a suitable cocatalyst.

Abstract: The catalyst systems comprise as active constituents a) a titanium-containing solid component comprising a compound of titanium, a compound of magnesium, a halogen, an inorganic oxide as support and a carboxylic ester as electron donor compound, and also, as cocatalyst, b) an aluminum compound and c) optionally a further electron donor compound, wherein the inorganic oxide used has a pH of from 1 to 6, an average particle diameter of from 5 to 200 &mgr;m, an average primary particle diameter of from 1 to 20 &mgr;M and voids or channels having an average diameter of from 0.1 to 20 &mgr;m and a macroscopic share of the volume of the overall particle within the range from 5 to 30%.

Abstract: The present invention relates to a supported catalyst system which comprises at least one metallocene component and at least one cocatalyst component and at least one modified inorganic oxide of silicon, aluminum or mixtures thereof, wherein the modified oxide contains organic silicon radicals containing at least one of the groups nitrogen, fluorine, phosphorus or sulfur.

Abstract: A metallocene compound is provided wherein to a transition metal compound is bonded a multidentate compound wherein a substituted cycloalkadienyl ring CA1 having therein a heteroaromatic group Ra containing an oxygen, sulfur or nitrogen atom on a cycloalkadienyl ring, preferably the five-membered ring thereof, and an unsubstituted or substituted cycloalkadienyl group CA2 or —(R1)N—, —O—, —S— or —(R1)P—, preferably CA2, more preferably a substituted cycloalkadienyl group identical with CA1 are bonded through a divalent linking group. The metallocene compound is suitable as a principal ingredient of a catalyst for the polymerization of olefins, particularly achieving a very high effect in making the molecular weight of a polypropylene higher.

Abstract: Procedure for the preparation of a solid catalyst component which is active in the polymerization of olefins, comprising the steps:a) contacting a dehydrated silica support with a solution of Mg-halide or Mg-alkyl-halide or a mixture of both, optionally in the presence of and Ti-alkoxyde or Ti-halogen-alkoxyde or a mixture of both,b) contacting the catalyst-precursor obtained in (a) with Mg-alkyl or Mg-alkyl-halide or a mixture of both, optionally in presence of electron-donors (Lewis bases),c) halogenating the catalyst-precursor obtained in (b) by contact of said activated support with halogenating agents,d) titanating the catalyst-precursor obtained in (c) with Ti-tetrahalide in the presence of electron-donors,e) recovering the solid catalyst-component from the reaction products of step (d).The catalyst component, which is obtained according to the above procedure, may also be used together with Al-trialkyl or Al-alkyl-halides and a Lewis base, as a catalyst for the polymerization of olefins.

Abstract: In catalyst systems of the Ziegler-Natta type modified during their preparation and 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 cocatalystb) an aluminum compound andc) if desired, a further electron donor compound,the titanium-containing solid component a) is prepared by first, in a first stage, admixing an inorganic oxide as support with a solution of a chlorine-free compound of magnesium in an inert solvent, stirring this mixture for from 0.5 to 5 hours at from 10 to 120.degree. C. and subsequently reacting it while stirring continually in an inert solvent with a C.sub.1 -C.sub.8 -alkanol in an at least 1.

Abstract: Catalytic systems particularly suitable for the polymerization of .alpha.-olefins containing from two to 20 carbon atoms, as well as for the copolymerization of ethylene with .alpha.-olefins containing from three to 20 carbon atoms, dienes, and cycloalkenes in processes wherein the catalyst is suspended in a solvent, in processes in gas phase, as well as in mass polymerization processes at high temperatures and pressures, are disclosed. The catalytic system is a mixture of a catalyst component A and a co-catalyst component B. The catalyst component A is formed by a functionalized inorganic porous oxide, by an organoaluminium compound and by an organometallic compound of a metal of the groups 3, 4, 5, or 6 of the periodic table. Functionalization of the inorganic oxide is by introduction of functional groups to be used to strongly fix the organoaluminium compound and the organometallic compound.

Abstract: An .alpha.-olefin polymerization catalyst which comprises:(A) a solid catalyst component containing a tetra-valent titanium obtained by treating a magnesium compound having an Mg--O bond in its molecule with a titanium halide;(B) an organoaluminum compound; and(C) an organosilicon compound represented by the general formula R.sup.1 R.sup.2 Si(OR.sup.3).sub.2wherein R.sup.1 represents a hydrocarbon group having 4 to 30 carbon atoms wherein a carbon bonded directly to Si is a tertiary carbon, R.sup.2 represents a straight chain hydrocarbon group having 2 to 10 carbon atoms and R.sup.3 represents a hydrocarbon group having 1 to 10 carbon atoms, or the general formula R.sup.4 R.sup.5 Si(OR.sup.6).sub.2wherein R.sup.4 and R.sup.5 are hydrocarbon groups having an alicyclic hydrocarbon having 5 carbon atoms as a basic structure, R.sup.4 and R.sup.5 may be the same or different, and R.sup.6 represents a hydrocarbon group having 1 to 10 carbon atoms, and a process for producing .alpha.-olefin with said catalyst.

Abstract: The instant invention teaches a method for forming a syndiotactic 1,2-polybutadiene product having a higher syndiotacticity and a higher melting temperature than syndiotactic 1,2-polybutadiene produced using chromium catalysts known in the prior art. The method includes polymerizing 1,3-butadiene in solution with a solvent, in the presence of catalytically effective amounts of: (a) a chromium compound; (b) an organomagnesium compound; and, (c) a cyclic hydrogen phosphite.

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: A process for the preparation of a meso/racemic-(bis(indenyl)ethane zirconium dichloride compound comprising (a) reacting zirconium tetrachloride with the solid reaction product of the bis(indenyl)ethane ligand with an alkyllithium in a solvent as reaction medium and (b) recovering a solid mixture of lithium chloride and meso/racemic composition of (bis(indenyl)ethane) zirconium dichloride, characterized in that the solvent used as reaction medium in a reaction (a) is an ether, pentane or a mixture thereof.

Abstract: Described are an aluminum compound-containing solid catalyst component obtained by bringing a carrier into contact with an organoaluminumoxy compound, followed by bringing this product into contact with a compound having an electron attractive group; a transition metal-containing solid catalyst component obtained by bringing the aluminum compound-containing solid catalyst component into contact with a transition metal compound; a catalyst for olefin polymerization, constituting the aluminum compound-containing solid catalyst component and an organoaluminum compound; and a method for producing an olefin polymer, which includes polymerizing or copolymerizing an olefim using the catalyst for olefin polymerization.

Abstract: Novel metallocene compounds are provided which are useful as polymerization catalysts, particularly in the polymerization of addition polymerizable monomers such as olefinic or vinyl monomers. Preferred polymer compositions prepared using the novel catalysts are bimodal or multimodal in nature, typically having a bimodal or multimodal molecular weight distribution. The metallocenes are binuclear or multinuclear, and contain two or more chemically distinct active sites. Methods for synthesizing the novel catalysts are also provided, as are methods for using the novel compounds as homogeneous or heterogeneous polymerization catalysts.

Abstract: This invention relates generally to supported metallocene catalyst systems and to methods for their production which comprising combining inorganic porous support material having an average particle size of from about 30.mu. to about 40.mu., metallocene, and alumoxane wherein the amount of metallocene is in the range of 0.005 to 0.06 mmoles transition metal/g support material and the ratio of aluminum to transition metal is in the range of 10:1 to 300:1. Specifically, this invention relates to supported metallocene catalyst systems having improved metallocene loading and optionally reduced support particle size. These catalyst systems are particularly useful for the polymerization of ethylene polymers.

Abstract: According to the present invention, there are provided a catalyst and a process for the preparation of polyolefins having a relatively wide molecular weight distribution, good particle properties, a narrow composition distribution in copolymerization and a high molecular weight and being less sticky. The catalyst is prepared by contacting the following constituents (1) to (4) with one another:(1) a compound represented by the general formula Me.sup.1 R.sup.1.sub.p (OR.sup.2).sub.q X.sub.4-p-q, where Me.sup.1 is Zr, Ti or Hf, R.sup.1 and R.sup.2 are each independently a hydrocarbon group having 1 to 24 carbon atoms, X is a halogen atom, p and q are each an integer in the ranges of 0.ltoreq.p.ltoreq.4 and 0.ltoreq.q.ltoreq.4 , provided 0.ltoreq.p+q.ltoreq.4;(2) a compound represented by the general formula Me.sup.2 R.sup.3.sub.m (OR.sup.4).sub.n X.sup.2.sub.z-m-n, where Me.sup.2 is a Group I-III element in the Periodic Table, R.sup.3 and R.sup.

Abstract: Catalysts deposited on a support are described. The catalyst itself is formed by combining (i) a metallocene of a transition, lanthanide or actinide metal and (ii) a siloxy-aluminoxane composition which comprises an aluminoxane which contains hydrocarbyl-siloxane moieties which are free of Si-OH groups, wherein the molar ratio of aluminum to hydrocarbylsiloxane is from about 1:1 to 1000:1. The siloxy-aluminoxane composition used is free of Si-OH groups, and the aluminoxane of the siloxy-aluminoxane composition was formed by partial hydrolysis of trialkylaluminum. Supports for the catalysts are particulate inorganic oxides, preferably silica, alumina, silica-alumina, or a mixture thereof, or resinous polyolefin support materials.

Abstract: Catalyst systems of the type comprising the Ziegler-Natta catalysts contain, as active components,a) a titanium-containing solid component which contains titanium, magnesium, halogen and a carboxylic ester as an electron donor, and, as a cocatalyst,b) an aluminum compound andc) if required, a further electron donor, a compound of the following formula IR.sub.m.sbsb.1 Al--(OCOR.sup.1).sub.m.sbsb.2 (I)whereR and R.sup.1 are identical or different and are each hydrogen or C.sub.1 -C.sub.8 -alkyl andm.sub.1 and m.sub.2 are each 1 or 2 and sum to give 3, being used as aluminum compound b) in the preactivation of the titanium-containing soild compound a) with the cocatalyst.

Abstract: A solid, hydrocarbon-insoluble, catalyst component useful in polymerizing olefins containing magnesium, titanium, and halogen further contains an internal electron donor comprising ##STR1## wherein R is selected from C.sub.1 -C.sub.8 alkyl, C.sub.6 -C.sub.9 aryl or C.sub.1 -C.sub.8 alkoxy groups; and wherein X and Y are N-R', O, P(O)(OR'), P(O)R', or S, and R' is selected from hydrogen, C.sub.1 -C.sub.8 alkyl and alkoxy, and C.sub.6 -C.sub.9 aryl groups, provided that up to two Y groups may be CR'.sub.2 groups.

Abstract: A method is provided for synthesizing metallocene compounds useful as polymerization catalysts and the like. The method involves (a) preparation of an amino alcohol-derived ligand by reacting a silane reactant with an amino alcohol in the presence of base, followed by (b) metallation of the ligand so provided. The metallocenes may be provided in chiral form when the amino alcohol contains an asymmetric center, and are thus useful in catalyzing stereospecific polymerization and other stereospecific bond formation reactions.

Abstract: The invention relates to a catalyst component which is a tract product of reagents comprising silica which has a pore volume which exceeds 2.9 cc/gram and an average pore diameter which exceed 400 Angstroms;a metallocene of a first transition metal, activated by an alumoxane,a contact product of dialkylmagnesium and trialkylsilanol,a second transition metal source which exhibits a hydrogen response which is different from that of the metallocenean olefin of 4 to 20 carbon atoms. This catalyst component is activated by an aluminum alkyl activator.

Abstract: A novel process for the preparation of Ziegler-Natta catalyst systems containing, as active components,a) a titanium-containing solid component which contains titanium, magnesium, halogen and a carboxylic ester and, as a cocatalyst,b) an aluminum compound andc) if required, a further electron donor is described. Ziegler-Natta catalyst systems which are obtainable by this process, the preparation of polymers of propylene with the aid of these catalyst systems, the polymers obtainable thereby and films and moldings of these polymers are also described.

Abstract: Procedure for the preparation of a solid catalyst component which is active in the polymerization of olefins, comprising the steps:a) contacting a silylated silica support with a solution of Mg-halide or Mg-alkyl-halide or a mixture of both and Ti-alkoxide or Ti-halogen-alkoxide or a mixture of both, optionally in the presence of Ti-tetrahalide,b) contacting the catalyst-precursor obtained in (a) with Mg-alkyl or Mg-alkyl-halide or a mixture of both, optionally in presence of Lewis base,c) halogenating the catalyst-precursor obtained in (b) by contact of said activated support with halogenating agents,d) titanating the catalyst-precursor obtained in (c) with Ti-tetrahalide in the presence of electron-donors,e) recovering the solid catalyst-component from the reaction products of step (d).The catalyst component, which is obtained according to the above procedure, may also be used together with Al-trialkyl or Al-alkyl-halides and a Lewis base, as a catalyst for the polymerization of olefins.

Abstract: A gas phase fluidized bed process is described for producing ethylene polymers having improved processability and an MWD of less than about 2.9. Multiple reactors in series or parallel may be used to produce in-situ blended polymers. Each reactor can separately have a constrained geometry catalyst or a conventional Ziegler-Natta catalyst as needed for obtaining in-situ blended polymer with the desired properties as long as there is a constrained geometry catalyst in at least one reactor. Olefin polymers can be produced according to this invention which have low susceptibility to melt fracture, even under high shear stress conditions.

Abstract: Solid mixed oxides composition of formula (I):Mo.sub.12 V.sub.a Sr.sub.b W.sub.c Cu.sub.d Si.sub.e O.sub.x(I)2.ltoreq.a.ltoreq.14, 0.1.ltoreq.B.ltoreq.6, 0.ltoreq.c.ltoreq.12, 0.ltoreq.d.ltoreq.6, 0.ltoreq.e.ltoreq.15; x is the quantity of oxygen bonded to the other elements and depends on their oxidation states, are used in the manufacture of acrylic acid by oxidation of acrolein, the said solid composition reacting with acrolein according to the redox reaction (1):SOLID.sub.oxidized +ACROLEIN.fwdarw.SOLID.sub.reduced +ACRYLIC ACID(1).To manufacture acrylic acid, a gaseous mixture of acrolein and of water vapor and, if appropriate, of an inert gas is passed over a solid composition of formula (I), to conduct the redox reaction (1) by operating at a temperature of 200 to 500.degree. C., at a pressure of 1.01.times.10.sup.4 to 1.01.times.10.sup.6 Pa (0.1 to 10 atmospheres), and with a residence time of 0.01 second to 90 seconds, in the absence of molecular oxygen.

Abstract: A preparation process for a catalytic support, based on a special alumina modified with varying quantities of magnesium chloride is described, a higher rate of MgCl.sub.2 leading to a lesser quantity of heavy molecular chains in the final polymer. The support, prepared by milling the special alumina together with the MgCl.sub.2 previously treated with ethyl benzoate, is impregnated with TiCl.sub.4 in order to create the catalyst. The resulting catalysts show high activity, which enables the metallic residue and chloride eliminating stage to be avoided in the resin so created. Furthermore the types of molecular weight distribution and of mechanical properties are different for the polymers produced.

Abstract: A process for preparing random propylene copolymers containing copolymerized C.sub.2 -C.sub.10 -alk-1-enes by polymerization of propylene and C.sub.2 -C.sub.10 -alk-1-enes in the presence of a Ziegler-Natta catalyst system comprising a titanium-containing solid component a) comprising a compound of magnesium, a halogen, silica gel as support and a carboxylic ester as electron donor compound, and also, as cocatalysts, an aluminum compound b) and a further electron donor compound c), where propylene and the C.sub.2 -C.sub.10 -alk-1-enes are polymerized with one another at from 50 to 100.degree. C. at pressures in the range from 15 to 40 bar and mean residence times of from 0.5 to 5 hours and the support used in the titanium-containing solid component is a silica gel which has a mean particle diameter of from 5 to 200 .mu.m, a mean particle diameter of the primary particles of from 1 to 10 .mu.m and voids or channels having a mean diameter of from 1 to 10 .mu.

Abstract: A novel metallocene catalyst for the polymerization of olefin (co)polymers is of the general formula:R--SO.sub.2 --L--M--(X).sub.m T.sub.nwherein,M is a metal selected from Groups 3-10;T is a polymerization-stable anionic ancillary ligand;m+n is the valency of M minus 1;R is a C.sub.1 -C.sub.20 alkyl group, a C.sub.6 -C.sub.20 aryl ring or a C.sub.6 -C.sub.20 alkaryl or aralkyl group, optionally substituted with a halogen or an alkoxy group up to 10 carbon atoms;X is a halogen, alkoxy from C.sub.1 to C.sub.20, siloxy from C.sub.1 to C.sub.20, N(R).sub.2, a hydrocarbyl group containing up to about 12 carbon atoms, hydrogen or another univalent anionic ligand, or mixtures thereof;L is T as defined above with the proviso that one of the sites available for substitution is the attachment site of the sulfonyl group; andwherein L and T may be bridged.

Abstract: The olefin polymerization catalyst of the invention is formed from a Group IVB transition metal compound represented by the following formula (I) and an organoaluminum oxy-compound or a compound which reacts with the transition metal compound to form an ion pair. In the olefin polymerization process of the invention using this catalyst or a catalyst formed from a Group IVB transition metal compound represented by the following formula (II) and an organoaluminum oxy-compound or a compound which reacts with the transition metal compound to form an ion pair, an olefin (co)polymer having a high molecular weight can be obtained with high polymerization activities, and besides an olefin copolymer having a high comonomer content can be obtained even if a comonomer is used in a small amount. ##STR1## wherein, M is a transition metal of Group IVB, at least one of R.sup.1 is an aryl group and the remainder is hydrogen or the like, R.sup.2 is hydrogen, an alkyl group or the like, R.sup.3 and R.sup.

Abstract: Catalytic system which can be used for the polymerization of .alpha.-olefins comprising:a solid based on complexed titanium trichloride of .delta. crystalline form;an organoaluminium compound;an organic oxygenated silicon compound;characterized in that the organoaluminium compound is a non-halogenated compound.

Abstract: A catalyst having a high pore volume, high surface area porous silica support and a non-metallocene, Ziegler-Natta catalytic component incorporated on the silica support is provided for the production of polyolefins from .alpha.-olefins. The porous silica support is made up of silica gel particles having an average surface area of about 600 to about 800 m.sup.2 /g of silica and an average pore volume of about 2.5 to about 4.0 ml/g of silica. Preferably, the silica particles have an average surface area of about 650 to about 750 m.sup.2 /g of silica and an average pore volume of about 2.75 to about 3.25 ml/g of silica. Even more preferably, the silica particles have an average surface area of about 700 m.sup.2 /g of silica and an average pore volume of about 3.0 ml/g of silica. The catalytic component comprises a complex product of a transition metal halide and a metal alkyl which excludes cyclopentadienyl rings.

Abstract: A process is described for forming a catalyst precursor, for copolymerizing ethylene and an alpha-olefin of 3 to 10 carbon atoms, by preparing a contact mixture of an inert solvent, dibutylmagnesium and tetraalkyl orthosilicate which is free of precipitate and adding silica to the contact mixture to form a slurry to form a supported catalyst precursor. Titanium tetrachloride is then incorporated into the support in a specific ratio to the magnesium and silane components. Activation of this catalyst precursor with a trialkylaluminum compound results in a catalyst system which is effective for the production of ethylene copolymers.

Abstract: A carbon body, in particular a pre-baked anode of an electrolytic cell for the production of aluminium by the electrolysis of alumina in a molten fluoride electrolyte is treated over its surfaces to improve the resistance thereof to deterioration during operation of the cell by air and oxidizing gases released at the anode, by treating the body with a treating liquid comprising a precipitable boron-containing compound and an additive, said additive being present in an amount so that substantially no separate phase from said the precipitate of said boron-containing compound is formed upon curing. Suitable boron oxide additives include colloidal alumina, silica, yttria, ceria, thoria, zirconia, magnesia, lithia, monoaluminium phosphate, cerium acetate and mixtures thereof. The same treatment can also be applied to a carbon mass forming a Soderberg anode and to cell sidewalls.

Abstract: Catalyst component for the polymerization of alpha-olefins of general formula (I) ##STR1## wherein: M is a transition metal of groups 3, 4-10, lanthanide or actinide of the periodic table of the elements; A is a ring with delocalized .pi. electrons, L is a neutral Lewis base; m is an integer whose value can be: 0 or 1; E is selected from the group comprising: BR.sup.II, CR.sup.II.sub.2, SiR.sup.II.sub.2, GeR.sup.II.sub.2 ; Hal is selected from the group comprising iodine, bromine or chlorine; R.sup.III has the same meaning of R.sup.II ; Si is a silicon atom; D is selected from the group comprising: O, S, NR.sup.IV, PR.sup.IV, OR.sup.IV, SR.sup.IV, NR.sup.IV.sub.2, PR.sup.IV.sub.2 ; each X group equal to or different from each other is selected from the group comprising hydrogen, halide, alkyl, cycloalkyl, aryl, alkenyl, arylallyl, arylalkenyl or alkylaryl with 1 to 20 carbon atoms, n is a number whose value can be: 0, 1, 2 or 3, in order to full the remaining valences of metal M.

Abstract: Disclosed is a high density ethylene polymer comprising a homopolymer of ethylene, or a copolymer of ethylene with at least one comonomer selected from an .alpha.-olefin, a cyclic olefin, and linear, branched and cyclic dienes, and having the following properties: (a) a density d (g/cm.sup.3) of from 0.951 to 0.980; (b) an M.sub.I (g/10 minutes) of more than 3 and not more than 100 (M.sub.I is the melt flow rate as measured at 190.degree. C. under a load of 2.16 kg); (c) the polymer satisfying: log a.sub.kI .gtoreq.-0.844 log M.sub.I +1.462 [M.sub.I is as defined above, and a.sub.kI is the Izod impact strength (kgf.multidot.cm/cm.sup.2)]; (d) the polymer satisfying: log M.sub.IR .gtoreq.-0.094 log M.sub.I +1.520 [M.sub.I is as defined above, and M.sub.IR is the H.sub.MI /M.sub.I ratio in which H.sub.MI (g/10 minutes) is the melt flow rate as measured at 190.degree. C. under a load of 21.6 kg and M.sub.I is as defined above]; and wherein (e) the d (g/cm.sup.3) and the M.sub.I (g/10 minutes) satisfy: d.gtoreq.

Abstract: The invention is directed to a catalyst composition suitable for addition reactions of ethylenically and acetylenically unsaturated monomers comprising a metal oxide support having covalently bound to the surface thereof directly through the oxygen atom of the metal oxide an activator anion that is also ionically bound to a catalytically active transition metal cation compound. The invention includes a preparation process for the invention catalyst composition exemplified by reacting a Lewis acid, such as trisperfluorophenyl boron with residual silanol groups of a silica support, preferably then reacting with a Lewis base such as diethylaniline, so as to prepare a silica bound anionic activator that when combined with a suitable transition metal compound will protonate it so as to form the ionic catalyst system. Use of the invention catalyst to polymerize alpha-olefins is exemplified.

Abstract: The present invention relates to a multinuclear metallocene compound of the formula I, ##STR1## where M.sup.1 is a tetravalent metal, L.sup.1 are, independently of one another, identical or different and are each a substituted cyclopentadienyl group, L.sup.2 and L.sup.3 are, independently of one another, identical or different and are each a .pi. ligand, B are, independently of one another, identical or different and are each a divalent bridging unit, X are, independently of one another, identical or different and are each a hydrogen atom, a halogen atom, a C.sub.1 -C.sub.10 -fluorocarbon radical or a hydrocarbon-containing radical having 1-40 carbon atoms, and k is an integer from 0 to 10. The metallocene compound of the present invention is suitable as a catalyst component for preparing olefin polymers.