Abstract: A catalytic composition for the dimerization, the codimerization or the oligomerization of olefins is obtained by bringing into contact at least one nickel compound that contains a heterocyclic carbene with at least one hydrocarbylaluminum halide and optionally at least one organic solvent. It is used in a process of dimerization, codimerization or oligomerization of olefins.

Abstract: A method of dimerizing alpha-olefins to mostly linear internal olefin dimers using as a catalyst a transition metal complex with an activating co-catalyst.

Abstract: In order to carry out selective dimerization of propylene principally into branched dimers, a catalytic composition resulting from at least partly dissolving a nickel compound mixed or complexed with a tertiary phosphine carrying a functional group is used in a medium resulting from mixing at least one quaternary ammonium halide and/or at least one quaternary phosphonium halide, at least one aluminum halide and optionally at least one organometallic aluminum compound.

Abstract: A process for oligomerizing at least one heavy olefin having at least 5 carbon atoms per molecule in the presence of at least one co-fed light olefin having less than 5 carbon atoms per molecule is disclosed. The presence of the at least one co-fed light olefin results in increased C6=(C6 olefin) conversion (if present as one of the at least one heavy olefins), increased weight % of C11+ hydrocarbons in the C9+ material of the product and increased cetane of the C9+ material of the product as compared to the oligomerization of the at least one heavy olefin without the co-fed at least one light olefin.

Abstract: An acetal, wherein the acetal is 2,2-di(tetrahydrofurfuryloxy)propane as well as processed for producing the acetal and methods of using the acetal.

Abstract: The instant invention provides a process for substantially reducing the polymer cement viscosity or reducing the molecular weight distribution of the a conjugated diene polymer synthesized by using a charge of catalytically effective amounts of a rare earth catalyst and an organo magnesium component by adding an organo zinc component to the charge in an amount and under conditions sufficient to reduce the polymer cement viscosity. The invention also contemplates a catalyst compostion for substantially reducing the polymer cement viscosity of a polymer product as well the resultant polymer product.

Abstract: A copolymer of ethylene and an alpha-olefin having an ethylene content of from 30 to 90 mole %, a number average molecular weight of from 300 to 30,000 and a molecular weight distribution defined by a Q value (the ratio of the weight average molecular weight to the number average molecular weight of not more than 3 and a Z value (the ratio of the maximum value of the molecular weight to the minimum value of the molecular weight when the molecular weight is measured by gel permeation chromatography) of from 15 to 200. The said copolymer can be produced by a process comprising copolymerizing ethylene with an alpha-olefin in the liquid phase in the presence of a polymerization catalyst composed of a combination of a soluble vanadium compound and an organoaluminum compound in the co-presence of hydrogen, characterized in that(a) the copolymerization is carried out in a continuous manner,(b) the concentration of the vanadium compound in the polymerization system is maintained at 0.

Abstract: A process for the manufacture of linear alpha-olefins is disclosed. The process employs, for the purposes of oligomerizing an unsaturated aliphatic hydrocarbon to linear alpha-olefins, a catalyst mixture comprising titanium aryl and/or titanium alkoxide, organoaluminum halide and optionally one or more additives selected from a group containing phosphorus, oxygen and sulphur compounds.

Abstract: The present invention relates to a method of using polyolefin waxes prepared by means of metallocene catalysts as additive components in printing inks and surface coatings.

Abstract: A catalyst composition for a process of oligomerising ethylene to produce 1-butene and/or 1-hexene wherein the catalytic composition is obtained by mixing at least one chromium compound with at least one aryloxy aluminum compound with general formula R.sub.n Al(R'O).sub.3-n where R is a linear or branched hydrocarbyl radical containing 1 to 30 carbon atoms, R'O is an aryloxy radical containing 6 to 80 carbon atoms and n is a whole number which can take the values 0, 1 or 2, and with at least one other hydrocarbyl aluminum compound selected from tris(hydrocarbyl)aluminum compounds or chlorinated or brominated hydrocarbyl aluminum compounds.

Abstract: A process to maximize the production of low molecular weight alpha olefins from ethylene is disclosed. The process comprises oligomerizing ethylene in the presence of a catalyst, of titanium aryloxide and/or titanium alkoxide; alkyl aluminum halide and triaryl phosphine and/or trialkyl phosphine in the temperature range of 80.degree. C. to 110.degree. C. at substantially low pressures of from 60 to 150 psi. A continuous supply of ethylene is maintained.

Abstract: The invention relates to a process for preparing monofunctional, bifunctional or polyfunctional aromatic olefins of the formula (I) ##STR1## wherein a palladium compound of the formula (IV) ##STR2## is used as a catalyst in the preparation of the compounds of the formula (I).

Abstract: The use of novel heterogeneous catalyst complexes as catalysts for oligomerizing alpha-olefins is disclosed. The complexes are formed from (i) a solid olefin polymer having a linear backbone and a plurality of pendant omega-hydroxyalkyl groups, (ii) an organomagnesium halide, and (iii) a boron trihalide, preferably BF.sub.3. The complexes can be recovered and reused repeatedly in batch-type operations and can be used for long periods of time in continuous or semi-continuous operations without replenishment of their boron trifluoride content.

Abstract: A process is provided to modify an olefin production catalyst system which comprises contacting an olefin production catalyst system with ethylene prior to use. A process also is provided to trimerize and/or oligomerize olefins with the novel, modified olefin catalyst production system. The modified olefin production catalyst system produces less solids, such as, for example, polymer.

Abstract: Catalyst systems which are suitable for polymerizing olefinically unsaturated compounds comprise as active constituentsA) a metallocene complex of the metals of the fourth, fifth or sixth transition group of the Periodic Table of the Elements,B) a compound forming metallocenium ions andC) a sterically hindered, organic Lewis base.

Abstract: Catalysts for preparing ethylene by conversion of methane or purified natural gas and preparation thereof, and process for preparation of ethylene by direct conversion of methane or purified natural gas using said catalysts. The catalysts have the formula I as follows:Ma,Pc/S (I)wherein, M is a compound selected from the group consisting of RuCl.sub.2 (PPh.sub.3).sub.3, RuCl.sub.2 (CO).sub.2 (PPh.sub.3).sub.2, Ru.sub.3 (CO).sub.12, RhCl(CO)(PPh.sub.3).sub.2, IrCl(CO)PPh.sub.3).sub.3, Pd(PPh.sub.3).sub.4, Pt(PPh.sub.3).sub.4 and RuCl.sub.3.xH.sub.2 O, S is an inorganic carrier selected from the group consisting of .alpha.-Al.sub.2 O.sub.3, .gamma.-Al.sub.2 O.sub.3, SiO.sub.2, SiO.sub.2 -Al.sub.2 O.sub.3,Y-zeolite, MgO and TiO.sub.2, and P is a phosphorus compound promoter selected from the group consisting of PPh.sub.3, P(OCH.sub.3).sub.3, P(OC.sub.2 H.sub.5).sub.3, and P(O)(OC.sub.2 H.sub.5).sub.3 ; wherein a is the amount of metal in the catalyst, ranging from 0.

Abstract: Disclosed herein are processes for polymerizing ethylene, acyclic olefins, and/or selected cyclic olefins, and optionally selected olefinic esters or carboxylic acids, and other monomers. The polymerizations are catalyzed by selected transition metal compounds, and sometimes other co-catalysts. Since some of the polymerizations exhibit some characteristics of living polymerizations, block copolymers can be readily made. Many of the polymers produced are often novel, particularly in regard to their microstructure, which gives some of them unusual properties. Numerous novel catalysts are disclosed, as well as some novel processes for making them. The polymers made are useful as elastomers, molding resins, in adhesives, etc. Also described herein is the synthesis of linear .alpha.-olefins by the oligomerization of ethylene using as a catalyst system a combination a nickel compound having a selected .alpha.-diimine ligand and a selected Lewis or Bronsted acid, or by contacting selected .alpha.

Abstract: A process is provided to trimerize or oligomerize olefins in the presence of an olefin oligomerization catalyst and a solvent which is a product of the olefin oligomerization process.

Abstract: A process for producing an vinylidene olefin of the formula ##STR1## where R.sup.1 and R.sup.2 are the same or different and are hydrogen or alkyl and m is an integer of from 0 to 18, with a catalytically effective amount of a mixture of i) an aluminum compound of the formula R.sup.4.sub.n Al(OR.sup.5).sub.p where R.sup.4 and R.sup.5 are the same or different and are alkyl, n is an integer from 0.75 to 2.75, and p is an integer from 0.25 to 2.25, the sum of n and p being 3, at a temperature of from about 120.degree. C. to about 200.degree. C. whereby a major amount of said vinylidene and deep internal olefin dimer is produced and only a minor amount of a beta internal olefin isomer.

Abstract: Ethylene is trimerized to form 1-hexene by using a catalyst comprising an aluminoxane and polydentate phosphine, arsine, and/or stibine coordination complex of a chromium salt. Catalysts, complexes, and ligands enabling production of 1-hexene in extremely high yields and purity are also described.

Abstract: Alpha-olefin oligomer is prepared by contacting an alpha-olefin monomer which contains from about 8 to about 16 carbon atoms with a heterogeneous catalyst system formed from (i) a solid olefin polymer having a linear backbone and a plurality of pendant omega-hydroxyalkyl groups, and (ii) a boron trihalide, preferably BF.sub.3. The catalyst system is stable and very reactive at relatively high temperatures, and the solid polymer of the catalyst system can be recovered and reused repeatedly in batch-type operations and can be used for long periods of time in continuous or semi-continuous operations.

Abstract: The invention concerns an improved process for the conversion of ethylene into but-1-ene, wherein the ethylene is brought into contact with a catalyst obtained by the interaction of an alkyl titanate, possibly mixed with an ether, with a compound of aluminium of the formula AlR.sub.3 or AlR.sub.2 H, and in the presence of an additive formed by at least one polyethylene glycol and/or one of its derivatives such as a monoether or a monoester of polyethylene glycol.

Abstract: Novel chromium-containing compounds, such as, for example, chromium pyrrolides, are prepared by forming a mixture of a chromium salt, a metal amide, and an electron pair donor solvent, such as, for example, an ether. These novel chromium-containing, or chromium pyrrolide, compounds can be used either unsupported or supported on an inorganic oxide support, with a metal alkyl and an unsaturated hydrocarbon, to trimerize, oligomerize, and/or polymerize olefins.

Abstract: Disclosed are ruthenium and osmium carbene compounds which are stable in the presence of a variety of functional groups and which can be used to catalyze olefin metathesis reactions on unstrained cyclic and acyclic olefins. Specifically, the present invention relates to carbene compounds of the formula ##STR1## wherein: M is Os or Ru; R and R.sup.1 are independently selected from hydrogen and functional groups C.sub.2 -C.sub.20 alkenyl, C.sub.2 -C.sub.20 alkynyl, C.sub.1 -C.sub.20 alkyl, aryl, C.sub.1 -C.sub.20 carboxylate, C.sub.2 -C.sub.20 alkoxy, C.sub.2 -C.sub.20 alkenyloxy, C.sub.2 -C.sub.20 alkynyloxy, aryloxy, C.sub.2 -C.sub.20 alkoxycarbonyl, C.sub.1 -C.sub.20 alkylthio, C.sub.1 -C.sub.20 alkylsulfonyl or C.sub.1 -C.sub.20 alkylsulfinyl; each optionally substituted with C.sub.1 -C.sub.5 alkyl, a halogen, C.sub.1 -C.sub.5 alkoxy or with a phenyl group optionally substituted with a halogen, C.sub.1 -C.sub.5 alkyl or C.sub.1 -C.sub.5 alkoxy; X and X.sup.

Abstract: The disclosure describes a process for preparing .alpha.-olefin oligomers, which comprises carrying out oligomerization of an .alpha.-olefin in a solvent by reacting said .alpha.-olefin in a chromium-based catalyst system composed of a combination of at least a chromium compound, an amine or metal amide, and an alkylaluminum compound, in a contacting mode that the chromium compound and the alkylaluminum compound are not previously contacted with each other.

Abstract: Alpha-olefin oligomers are produced by oligomerizing an alpha-olefin monomer with a catalyst system comprising boron trifluoride, a protic promoter, and a modifier which is (a) at least one 1,3-dioxolane, or (b) at least one 1,3-dioxane, or (c) a combination of (a) and (b). Use of these modifiers in the BF.sub.3 -catalyzed oligomerization makes it possible to modify the promoted catalytic reaction so that product containing as much as 50% or more of dimer can be produced at high conversions, at modest reaction temperatures, and in short reaction periods.

Abstract: Alpha-olefins enriched in 1-hexene are prepared by oligomerizing ethylene in the presence of a catalyst comprising (a) a chromium complex containing a coordinating polydentate ligand and, (b) an aluminoxane, in an organic solvent.

Abstract: A method for producing 3-methyl-2-pentene which is substantially free of any other C.sub.6 olefin, except 2-ethyl-1-butene, by first producing a stream that contains 2-ethyl-1-butene from the trimerization of ethylene, and second by recovering the 2-ethyl-1-butene as 3-methyl-2-pentene via etherification, separation of the ether, and decomposition of the ether back to predominantly 3-methyl-2-pentene with some 2-ethyl-1-butene.

Abstract: The present invention provides a process for producing olefin having a terminal double bond by trimerizing at least one monomer selected from a group consisting of ethylene, propylene, and 1-butene, which comprises using a catalyst comprising a product prepared from(1) component (A): a chromium compound represented by the formula ?1!CrXmYn ?1!wherein X represents carboxylic acid residue, 1,3-diketone residue, halogen atom or alkoxyl group, Y represents amine, phosphine, phosphine oxide, nitrosyl group or ether, m means an integer of from 2 to 4 and n means an integer of from 0 to 4,component (B): a heterocyclic compound having a pyrrole ring unit or an imidazole ring unit, andcomponent (C): an aluminum compound represented by the formula ?2!AlR.sub.k Z.sub.

Abstract: Disclosed are ruthenium and osmium carbene compounds which are stable in the presence of a variety of functional groups and which can be used to catalyze olefin metathesis reactions on unstrained cyclic and acyclic olefins. Specifically, the present invention relates to carbene compounds of the formula ##STR1## wherein: M is Os or Ru; R and R.sup.1 are independently selected from hydrogen and functional groups C.sub.2 -C.sub.20 alkenyl, C.sub.2 -C.sub.20 alkynyl, C.sub.1 -C.sub.20 alkyl, aryl, C.sub.1 -C.sub.20 carboxylate, C.sub.2 -C.sub.20 alkoxy, C.sub.2 -C.sub.20 alkenyloxy, C.sub.2 -C.sub.20 alkynyloxy, aryloxy, C.sub.2 -C.sub.20 alkoxycarbonyl, C.sub.1 -C.sub.20 alkylthio, C.sub.1 -C.sub.20 alkylsulfonyl or C.sub.1 -C.sub.20 alkylsulfinyl; each optionally substituted with C.sub.1 -C.sub.5 alkyl, a halogen, C.sub.1 -C.sub.5 alkoxy or with a phenyl group optionally substituted with a halogen, C.sub.1 -C.sub.5 alkyl or C.sub.1 -C.sub.5 alkoxy; X and X.sup.

Abstract: Methods of preparing carbene compounds of the formula ##STR1## are disclosed wherein M is Os or Ru; R and R.sup.1 are independently selected from hydrogen and a functional group selected from the group consisting of C.sub.2 -C.sub.20 alkenyl, C.sub.2 -C.sub.20 alkynyl, C.sub.1 -C.sub.20 alkyl, aryl, C.sub.1 -C.sub.20 carboxylate, C.sub.2 -C.sub.20 alkoxy, C.sub.2 -C.sub.20 alkenyloxy, C.sub.2 -C.sub.20 alkynyloxy, aryloxy, C.sub.2 -C.sub.20 alkoxycarbonyl, C.sub.1 -C.sub.20 alkylthio, C.sub.1 -C.sub.20 alkylsulfonyl or C.sub.1 -C.sub.20 alkylsulfinyl; each optionally substituted with C.sub.1 -C.sub.5 alkyl, a halogen, C.sub.1 -C.sub.5 alkoxy or with a phenyl group optionally substituted with a halogen, C.sub.1 -C.sub.5 alkyl or C.sub.1 -C.sub.5 alkoxy; X and X.sup.1 are independently selected from any anionic ligand; and L and L.sup.

Abstract: A process is provided comprising: (a) contacting a hydrocarbyl lithium with an alkali metal hydrocarbyloxide in the presence of an aromatic compound; and thereafter (b) recovering an aromatic alkali metal compound; and thereafter (c) contacting said aromatic alkali metal compound with an alpha-olefin. Optionally, a catalytic support is also present during steps a, b, and c.

Abstract: Catalysts and processes are described to make low molecular weight, essentially terminally-unsaturated, viscous poly(1-olefin) or copoly(1-olefin) having a high terminal vinylidine content from a feed stock containing one or more 1-olefin and other volatile hydrocarbon liquids using a Ziegler catalyst made from a Group IVb metallocene and an aluminoxane cocatalyst, particularly bis(cyclopentadienyl) and bis(indenyl) titanium(IV), zirconium(IV) or hafnium(IV) compounds and methylaluminoxane. A particularly useful feed stock is a refinery stream containing 1-olefins and isobutylene which is used to make polyisobutylene.

Abstract: A process is provided for producing liquid ethylene-type random copolymers by copolymerizing ethylene and a C.sub.3 --C.sub.2 O alpha-olefin in the presence of a catalyst comprising an alumoxane and a stereorigid metallocene compound described by the formula:R"(CpR.sub.5)(CpR'.sub.5)MeQ.sub.2wherein each Cp is a cyclopentadienyl or substituted cyclopentadienyl ring; each R and R' is the same or different and is hydrogen or a hydrocarbyl radical having 1-20 carbon atoms or two R or two R' together form a hydrocarbyl radical having 2-20 carbon atoms; R" is a structural bridge between the two Cp rings imparting stereorigidity to the compound; Me is a transition metal of Group IVb of the periodic table; and each Q is a hydrocarbyl radical having 1-20 carbon atoms or is a halogen. A portion of the alumoxane may be replaced with an alkylaluminum.

Abstract: Vinylidene olefin can be formed in good yield and high selectivity in much shorter reaction periods than found critical heretofore. The process involves dimerizing vinyl olefin with at least one trialkylaluminum compound as the catalyst component charged to the reaction vessel. These materials are charged to the reactor so that it contains in the range of 0.001 to 0.5 mol of trialkylaluminum per mol of the initial vinyl olefin. The reaction is performed at a temperature in the range of 100.degree. to 200.degree. C. for a period of time sufficient to convert 10 to 99% by weight of the initial vinyl olefin to a different product with at least 80 wt % vinylidene dimer selectivity. In conducting the process the liquid reaction mixture is in direct contact with a nickel-containing metal alloy surface for at least one hour at a temperature above about 50.degree. C.

Abstract: Vinylidene olefin can be formed in good yield and high selectivity in much shorter reaction periods than found critical heretofore. The process involves dimerizing vinyl olefin with at least one trialkylaluminum compound as the sole catalyst component charged to the reaction vessel. These materials are charged to the reactor so that it contains in the range of 0.001 to 0.5 mol of trialkylaluminum per mol of the initial vinyl olefin. The reaction is performed at a temperature in the range of 100.degree. to 200.degree. C. for a period of time sufficient to convert 10 to 99% by weight of the initial vinyl olefin to a different product and form a product mixture with at least 80 wt % vinylidene dimer selectivity.

Abstract: A method for polymerizing or copolymerizing .alpha.-olefin in a vapor phase condition by supplying to a reactor a catalyst composed of a solid catalyst component containing at least titanium and/or vanadium as well as magnesium and an organic aluminum compound wherein the current due to the electric charge transferred from polymer particles electrified to an electrode disposed at a position where sheet-like polymers will be produced in a reactor, as a result of contact of the polymer particles in the reactor with the electrode is determined, and the polymerization or copolymerization is carried out under such condition where the mean value of current is zero or a positive value. As a result, it becomes possible to prevent production of sheet-like polymers and to stably continue the reaction for polymerization.

Abstract: A new class of olefin dimerization catalysts and an efficient method for their preparation is disclosed. B (C.sub.6 F.sub.5).sub.3 reacts quantitatively with Group 4 metallocene type catalysts to yield highly reactive cationic complexes as follows:(L.sub.2 MR.sup.2).sup.+ X.sup.- whereL=R.sub.2 (C.sub.5 H.sub.3); R=CR'.sub.3 ; R.sup.2 =alkyl group (C=1.ltoreq.20);M=Ti, Zr, Hf;X.sup.- =RB(C.sub.6 F.sub.5).sub.3.sup.-, or methylalumoxane.These complexes are potent catalysts and may be used in the dimerization of .alpha.-olefins.

Abstract: Vinylidene olefin can be formed in good yield in much shorter reaction periods than found critical heretofore. The process involves dimerizing vinyl olefin with at least one trialkylaluminum compound as the sole catalyst component charged to the reaction vessel. These materials are charged to the reactor so that it contains in the range of 0.001 to 0.05 mol of trialkylaluminum per mol of the initial vinyl olefin. The reaction is performed at a temperature in the range of over 140.degree. C. and below 172.degree. C. for a period of time in the range of 1 to 24 hours sufficient to convert at least 10% by weight of the initial vinyl olefin to a different product with at least 80 wt % vinylidene dimer selectivity.

Abstract: The present invention relates to the oligomerization of lower alpha olefins, and particularly ethylene, to higher olefins in the presence of a catalyst precursor having either or both of a dithiophosphinate complex and a heterobifunctional ligand having a phosphine center and an imine or similar center, in the presence of an activator. The catalysts have a high reactivity and a good selectivity.

Abstract: A novel Phillips catalyst for the copolymerization of ethylene with .alpha.-olefins, contains, as a catalytically active component, a finely divided, aluminum silicate-supported, phosphorus-containing chromium catalyst. This can be prepared by applying at least one organic phosphorus(III), (IV) and/or (V) compound and at least one chromium(III) compound which does not react with said phosphorus compounds under the reaction conditions used, in succcession in any order or simultaneously, to a finely divided aluminum silicate hydrogel or xerogel with formation of a catalyst intermediate and activating the catalyst intermediate at elevated temperatures in an oxidizing atmosphere, with the result that the chromium catalyst is formed. The novel Phillips catalyst gives ethylene/.alpha.-olefin copolymers in which the comonomers are more uniformly distributed over the copolymer chains than is the case with ethylene/.alpha.-olefin copolymers which have been prepared with the aid of conventional Phillips catalysts.

Abstract: Ethylene is trimerized to form 1-hexene by using a catalyst comprising an aluminoxane and polydentate phosphine, arsine, and/or stibine coordination complex of a chromium salt.

Abstract: Novel chromium-containing compounds, such as, for example, chromium pyrrolides, are prepared by forming a mixture of a chromium salt, a metal amide, and an electron pair donor solvent, such as, for example, an ether. These novel chromium-containing, or chromium pyrrolide, compounds can be used either unsupported or supported on an inorganic oxide support, with a metal alkyl and an unsaturated hydrocarbon, to trimerize, oligomerize, and/or polymerize olefins.

Abstract: .alpha.,.omega.-Diene oligomers which are useful as synthetic lubricants are prepared by oligomerizing a .alpha.,.omega.-diene using a trialkylaluminum catalyst.

Abstract: A method for producing 3-methyl-2-pentene which is substantially free of any other C.sub.6 olefin, except 2-ethyl-1-butene, by first producing a stream that contains 2-ethyl-1-butene from the trimerization of ethylene, and second by recovering the 2-ethyl-1-butene as 3-methyl-2-pentene via etherification, separation of the ether, and decomposition of the ether back to predominantly 3-methyl-2-pentene with some 2-ethyl-1-butene.

Abstract: A catalyst system composition and a process to prepare a catalyst composition comprising a cobalt compound, a metal alkyl and a coordinating compound is provided. The resultant catalyst system composition can be used to dimerize ethylene with high productivity to butenes and high selectivity to 1-butene.

Abstract: Organic aluminoxy compounds are prepared by reacting an organo boronic acid with a trihydrocarbyl aluminum compound. The resulting products are suitable as components for catalyst systems for the polymerization of olefins.

Abstract: The invention relates to the use of polymethylalkanes having terminal methyl groups and methylene and ethylidene groups of the formula I ##STR1## in which the total number of C atoms n+2 m+2 is 20 to 100 and the ratio of the methyl and methylene groups to the ethylidene groups is 3 to 20:1 and the ethylidene groups are always separated by at least one methylene group, as biodegradable base oils for lubricants and functional fluids. Suitable polymethylalkanes are obtained by oligomerization of .alpha.,.omega.-diolefins, for example in particular according to P 41 19 332.6, or by pyrolysis of ethene/propane copolymers and subsequent hydrogenation in each case. The polymethylalkanes can be combined with conventional additives and other degradable or non-degradable base oils.

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: The synthesis, and use as precatalysts of chiral organozirconium complexes for olefin polymerization are disclosed, having the structure (C.sub.5 R'.sub.4-x R*.sub.x) A (C.sub.5 R".sub.4-y R'".sub.y) M Q.sub.p, where x and y represent the number of unsubstituted locations on the cyclopentadienyl ring; R', R", R'", and R* represent substituted and unsubstituted alkyl groups having 1-30 carbon atoms and R* is a chiral ligand; A is a fragment containing a Group 13, 14, 15, or 16 element of the Periodic Table; M is a Group 3, 4, or 5 metal of the Periodic Table; and Q is a hydrocarbyl radical, or halogen radical, with 3.ltoreq.p.ltoreq.o. Related complexes may be prepared by alkylation of the corresponding dichorides. In the presence of methylalumoxane or triarylborane cocatalysts, these complexes form "cation-like" species which are highly active for olefin polymerization. In combination with a Lewis acid cocatalyst, propylene or other .alpha.