Post-metallocene polyolefin catalyst compounds

Abstract

This invention relates to compounds according to Formula 1: wherein M is a metal atom selected from Hf, Ti, and Zr; X is a halogen, a C1-C4 alkyl moiety, or a benzyl moiety; R1 is a C1-C4 alkyl moiety; R2, R3, R4, R5, and R6 are each the same or different; R7 and R8 are each a C1-C4 alkyl moiety, preferably methyl, and preferably R7 and R8 are the same; and wherein R2, R3, R4, R5, and R6 are each individually selected from hydrogen, C1-C4 alkyl, methoxy, phenyl, benzyl, 2-phenylpropyl, 2,2'-diphenylethyl, 2,4,6-trimethylphenyl, 3,5-dimethylphenyl, 3,5-di-tert-butylphenyl, 9 H 9-Carbazole-9-yl, 9-Methyl-9 H -fluorene-9-yl and adamantyl. Such compounds allow for their use as catalysts in olefin polymerization with particularly high polymerization activity, achieving the desired high incorporation and high molecular weight of comonomers in olefin copolymerization reactions. (1)

Description

[0001] This invention relates to post-metallocene polyolefin catalyst compounds. It also relates to methods for producing polyolefins using such post-metallocene catalyst compounds. Furthermore, it relates to the application of such compounds in catalytic systems suitable for use in polymerization (e.g., in the polymerization of olefins). Such catalytic systems allow for the production of polymers with particularly high polymerization activity, exhibiting high incorporation of comonomers and high molecular weights desired in olefin copolymerization reactions.

[0002] Polymers of ethylene and other olefins are readily available and have found wide applications. Typical examples of olefin-based polymers include various types of polymers produced by reacting specific reaction mixtures in the presence of a catalytic system. Examples of ethylene-based copolymers include, for example, medium-density polyethylene (MDPE), linear low-density polyethylene (LLDPE), polyolefin plastomers (POP), polyolefin elastomers (POE), and ethylene-propylene-diene terpolymers (EPDM). Such polymers are typically produced using transition metal-based catalyst systems. For these polymers to be suitable materials for applications of significant commercial importance, they must have a specific molecular weight, expressed as a weight-average molecular weight (M). w The value indicates, for example, at least 10 kg / mol, preferably at least 50 kg / mol, but even more preferably at least 100 kg / mol, and can be, for example, in the range of 100 kg / mol to 500 kg / mol, to provide polymer products that exhibit the desired product quality combined with processability via melt molding processes (such as those commonly used in molding products based on polymer materials).

[0003] In addition, another ethylene-based polymer produced using catalytic systems is high-density polyethylene (HDPE), such as bimodal HDPE, which is used in demanding applications such as pressure piping. Such bimodal HDPE typically comprises a low molecular weight fraction of ethylene homopolymer and a high molecular weight fraction of ethylene-based copolymer. The high molecular weight fraction of such bimodal HDPE typically has an M0 greater than 100 kg / mol, or even greater than 300 kg / mol, or even greater than 500 kg / mol. w .

[0004] In addition, another commercial type of polyethylene is ultra-high molecular weight polyethylene (UHMWPE), which has a typical molecular weight of even higher than 1000 kg / mol, and has been found to have applications in high-performance applications.

[0005] To commercially manufacture olefin-based polymers (such as those mentioned above), and to provide improved process economics, as well as improvements in product quality and properties, there remains a continued impetus to develop catalyst systems that can contribute to this.

[0006] Specific aspects related to the catalyst system used in olefin polymerization include catalyst activity, comonomer incorporation capacity, and the ability to produce polymer products with high molecular weights. Catalyst activity represents the amount of polymer product obtained per unit amount of catalyst used. Comonomer incorporation capacity represents the amount of comonomer that reacts into the polymer when polymerization occurs in the presence of a given amount of comonomer in the reaction mixture; this is due to the relatively low reactivity of comonomers compared to the host monomer. Increasing the reactivity of the comonomer is desirable in order to minimize the concentration of comonomer in the reaction mixture, which is desirable from the perspective of process optimization and economics.

[0007] Another known trend in the preparation of olefin-based polymers, particularly copolymers based on ethylene and α-olefins (e.g., α-olefins containing 3-10 carbon atoms), is that the molecular weight of the obtained copolymer decreases with increasing content of comonomers incorporated into the polymer chain. Therefore, a persistent challenge is to combine the desired incorporation of comonomers in polymerization, for example, ethylene, with the desired high molecular weight.

[0008] An additional trend commonly observed in the preparation of such polymers is a decrease in the maximum achievable molecular weight as the polymerization temperature increases. This can be disadvantageous, particularly in so-called solution polymerization methods. In such methods, the polymer is formed in a solvent at a temperature higher than the crystallization temperature of the polymer formed. Preferably, the polymerization temperature in such methods is above 100°C, more preferably above 120°C, and even more preferably above 150°C. Therefore, finding a suitable catalyst capable of producing high molecular weight copolymers at high polymerization temperatures while still exhibiting favorable catalytic activity is not straightforward. In such methods, the temperature of the contents leaving the polymerization reactor is typically further increased to promote the evaporation of a portion of the solvent and residual monomers. This temperature increase requires energy, and therefore, if the polymerization temperature is already high, less energy is required for the additional temperature increase to promote evaporation.

[0009] Various types of catalysts have been developed over the years and have found commercial implementation in various process concepts for polymerization, and are widely disclosed in the literature. A particular group of catalysts is the monocentric catalyst. In such catalyst compounds, a single class of catalytically active substances exists, which translates into narrow polydispersity (defined as molecular weight distribution (M...). w / M nAnd a narrow compositional distribution (which tends to result in the particularly desirable mechanical properties of the obtained polymer).

[0010] This class of single-center catalysts includes a group of catalysts known as post-metallocene catalysts. Such post-metallocenes should be understood as compounds comprising discrete transition metal compounds, wherein the compounds do not contain the cyclopentadienyl or substituted cyclopentadienyl structural moieties present in the metallocene catalyst.

[0011] Of particular interest are post-metallocenes containing amine-bisphenolate ligands. Transition metal compounds containing amine-bisphenolate ligands are known. In such complexes, the amine group of the aromatic ring connecting the two phenolate moieties is typically substituted via a hydrocarbon spacer group to an electron-donating group that can coordinate with the transition metal. For example, such amine-bis(phenolate) zirconium compounds and their ability to be used as catalysts for olefin polymerization are described by Kol et al. in Chemical Communications, 2000(5), pp. 379-380 and Organometallics 2002(21), pp. 662-670, and by Waymouth et al. in Macromolecules, 2005(38), pp. 2552-2558. All these publications teach that in these amine-bisphenolate compounds, nitrogen is attached to the aromatic moieties of the phenolate group via a spacer group (typically a divalent hydrocarbon group, such as a methylene spacer group).

[0012] There is still a need to expand the performance range of catalysts that can produce amorphous or semi-crystalline polyolefins in high yields, exhibit high reactivity for comonomer incorporation (e.g., copolymerization of ethylene with 1-hexene or other sterically hindered olefins) at favorable high polymerization temperatures, and still yield high molecular weight copolymers.

[0013] According to the present invention, this is now achieved by a compound according to Formula 1:

[0014] Formula 1

[0015] in

[0016] M is a metal atom selected from Hf, Ti, and Zr;

[0017] X is a halogen, a C1-C4 alkyl moiety, or a benzyl moiety;

[0018] R1 is a C1-C4 alkyl structural moiety;

[0019] R2, R3, R4, R5, and R6 may be the same or different;

[0020] R7 and R8 are each C1-C4 alkyl structural moieties, preferably methyl, and preferably R7 and R8 are the same; and

[0021] R2, R3, R4, R5, and R6 are each individually selected from hydrogen, C1-C4 alkyl, methoxy, phenyl, benzyl, 2-phenylpropyl, 2,2'-diphenylethyl, 2,4,6-trimethylphenyl, 3,5-dimethylphenyl, 3,5-di-tert-butylphenyl, 9 H -Carbazole-9-yl, 9-methyl-9 H -fluorene-9-yl and adamantyl.

[0022] Such compounds allow for their use as catalysts in olefin polymerization with exceptionally high polymerization activity, enabling the high incorporation of desired comonomers and high molecular weights in olefin copolymerization reactions.

[0023] In a preferred embodiment, the compound is a compound according to Formula 2:

[0024] Formula 2

[0025] Preferably, M is selected from Hf and Zr. X can be, for example, a methyl moiety, a benzyl moiety, or a chlorine atom. Preferably, the two X moieties are the same.

[0026] In a preferred embodiment of the invention, R1 is a methyl moiety. R2 may be selected, for example, from hydrogen, methyl, methoxy, isobutyl, tert-butyl, and adamantyl, preferably from methyl, tert-butyl, and adamantyl. R3 may be selected, for example, from hydrogen, methyl, methoxy, tert-butyl, and adamantyl, preferably R3 is methyl. R4 may be selected, for example, from hydrogen, methyl, methoxy, tert-butyl, and adamantyl, preferably from hydrogen, methoxy, and adamantyl. R5 may be selected, for example, from hydrogen, methyl, methoxy, tert-butyl, and adamantyl, preferably wherein R5 is methyl. R6 may be selected, for example, from hydrogen, methyl, methoxy, tert-butyl, and adamantyl, preferably from methyl, tert-butyl, and adamantyl.

[0027] In embodiments, the invention also relates to catalyst systems comprising the compound. In a preferred embodiment, such a catalyst system further comprises an activator selected from aluminoxane compounds and boron-based compounds, optionally in the presence of an alkylaluminum compound. Such aluminoxane compounds may be, for example, selected from methylaluminoxane, isobutylaluminoxane, and methyl-isobutylaluminoxane. Such boron-based compounds may be, for example, selected from tris(pentafluorophenyl)borane and tetra(pentafluorophenyl)borate, such as ammonium tetra(pentafluorophenyl)borate, such as N,N'-dimethylphenylammonium tetra(pentafluorophenyl)borate. Another example is triphenyltetra(pentafluorophenyl)borate.

[0028] The catalyst system may, for example, comprise a compound according to the invention supported on a support material, wherein the support material is selected from polymer support materials, clay materials, solid aluminoxanes or inorganic oxides, preferably wherein the support material comprises silica, alumina or solid aluminoxanes.

[0029] The present invention also relates to a method for the polymerization of olefins, preferably wherein the polymerization comprises reacting a reaction mixture containing ethylene and / or propylene in the presence of a catalyst system as described herein. Preferably, the method is a gas-phase, solution-phase, or slurry-phase process. Particularly preferred are homopolymerization methods of ethylene, homopolymerization methods of propylene, copolymerization methods of ethylene with a comonomer preferably selected from 1-butene, 1-hexene, 4-methyl-1-pentene, vinylcyclohexane, and 1-octene, or copolymerization methods of propylene with a comonomer preferably selected from ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, vinylcyclohexane, and 1-octene.

[0030] For example, the catalyst system may comprise a compound of Formula 1 supported on a carrier material, wherein the carrier material may be selected from polymeric carrier materials, clay materials, solid aluminoxanes, or inorganic oxides, preferably wherein the carrier material comprises silica, alumina, or a solid aluminoxane, such as solid methylaluminoxane (MAO). Suitable carrier materials may also include fluorinated silica-alumina supports or sulfated alumina supports. Using such a catalyst system in supported form may be advantageous for certain polymerization methods (e.g., gas-phase homopolymerization or copolymerization methods for the production of ethylene and propylene-based polymers). Alternatively, such a catalyst system may comprise a compound of Formula 1 in unsupported form.

[0031] In a preferred embodiment, the carrier has a surface area of ​​200 to 900 m². 2 / g and / or pore volume >0.5 and <4.0 ml / g of silica.

[0032] In another embodiment, the invention also relates to a method for polymerizing olefins, preferably wherein the polymerization comprises reacting a reaction mixture containing ethylene and / or propylene in the presence of a catalyst system according to the invention. Such a method may be, for example, a homopolymerization of ethylene, a homopolymerization of propylene, a copolymerization of ethylene with a comonomer preferably selected from 1-butene, 1-hexene, 4-methyl-1-pentene, vinylcyclohexane, and 1-octene, or a copolymerization of propylene with a comonomer preferably selected from ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, vinylcyclohexane, and 1-octene. For example, the method may be a gas-phase process, a solution process, or a slurry process.

[0033] In such polymerization methods, it is preferable to have a group organometallic compound that acts as a scavenger compound to remove impurities from the polymerization system that could otherwise adversely affect catalyst activity. When X in Formula 1 is a halogen, alkoxide, or amine moiety, an additional function of the group organometallic compound is to replace X with an organic group, such as an alkyl or aralkyl moiety, or, for example, a methyl, ethyl, propyl, isopropyl, butyl, isobutyl, or benzyl moiety. This function of the group organometallic compound is particularly advantageous when using activators other than aluminoxanes. Such group organometallic compounds are those capable of exchanging at least one of their organic moiety with X in the compounds of the present invention.

[0034] For example, organolithium compounds, organomagnesium compounds, organoaluminum compounds, organozinc compounds, or mixtures thereof can be used as such main group organometallic compounds. Preferably, the main group organometallic compound is an organoaluminum compound. Suitable organoaluminum compounds include, for example, trimethylaluminum, triethylaluminum, triisopropylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, tri-tert-butylaluminum, tripentylaluminum, tri-n-hexylaluminum, trioctylaluminum, isobutylisopentylaluminum, dimethylaluminum ethoxide, diethylaluminum ethoxide, diisopropylaluminum ethoxide, di-n-propylaluminum ethoxide, diisobutylaluminum ethoxide, di-n-butylaluminum ethoxide, dimethylaluminum hydride, diethylaluminum hydride, diisopropylaluminum hydride, di-n-propylaluminum hydride, diisobutylaluminum hydride, and di-n-butylaluminum hydride. Mixtures of these organoaluminum compounds are also suitable. Alternatively, aluminum oxanes can be used as such main group organometallic compounds. Suitable examples of aluminum oxanes are methylaluminoxanes, methyl-isobutylaluminoxanes, isobutylaluminoxanes, and mixtures thereof.

[0035] In some embodiments, it may be suitable to combine a main group organometallic compound with a compound containing at least one active hydrogen atom. Such combinations can be made in situ or ex-situ. In this context, active hydrogen means a hydrogen atom capable of reacting with the main group organometallic compound. In the context of this invention, suitable compounds containing at least one active hydrogen atom are, for example, alcohols, silanols, and amines. Suitable amines are sterically hindered amines. Examples of sterically hindered amines are cyclohexylamines or alkylamines containing at least one aliphatic group having at least four carbon atoms. Suitable alcohols are preferably sterically hindered alcohols, such as substituted phenols. In principle, any substituted mono- or polyphenolic compound can be used. Suitable substituted monophenolic compounds are, for example, butylated hydroxytoluene (BHT, 2,6-di-tert-butyl-4-methylphenol), 2,6-di-tert-butylphenol, and α-tocopherol (vitamin E). Preferably, the amount of the compound containing at least one active hydrogen is such that, after combining the compound with a main group organometallic compound, the latter still contains organometallic bonds, preferably at least one organometallic bond per main group metal atom.

[0036] A method for producing olefin polymers may begin with a reaction of the compounds of the present invention with an activator, optionally in the presence of a main group organometallic compound, optionally in the presence of a compound containing at least one active hydrogen atom, and optionally in the presence of a suitable support material. The reaction may be carried out in the same vessel as the reaction vessel used for producing the olefin polymer, or in a separate vessel. It is advantageous to first combine the compounds of the present invention with a portion of the amount of the main group organometallic compound to be used, optionally in the presence of a compound containing at least one active hydrogen atom, and then mix with the activator. The resulting mixture may be fed into a polymerization reactor. Inert solvents may be used in the reaction processes described herein.

[0037] The activator may be an aluminoxane-based activator. When using a mixture of the compounds of the present invention with such an aluminoxane-based activator, the activator is preferably used in an amount of 10 to 100,000 moles of aluminum, more preferably 10 to 10,000 moles of aluminum per mole of transition metal in the compounds of the present invention. When using aluminoxanes, especially methylaluminoxanes, as activators, it is known that such aluminoxanes may contain residual trimethylaluminum, sometimes referred to as free trimethylaluminum. The amount of free trimethylaluminum is usually specified by the supplier of the aluminoxane, but can also be determined by known analytical techniques. Treating such aluminoxane solutions with a compound containing at least one active hydrogen (e.g., BHT) is suitable. In this case, a suitable amount of the compound containing at least one active hydrogen can be expressed as a molar ratio relative to trimethylaluminum, for example, a molar ratio of active hydrogen to trimethylaluminum in the range of 3:1 to 0.1:1, or in the range of 2:1 to 1:1.

[0038] Alternatively, the activator may be an organoboron-based activator. When using a mixture of the compound of the present invention with such an organoboron-based activator, the activator may preferably be used in an amount of 0.1 to 100 moles of boron, preferably 0.5 to 50 moles of boron per mole of transition metal in the compound of the present invention.

[0039] This compound can also be used in catalyst systems containing a large number of different transition metal compounds, such as in mixed catalyst systems. For example, such mixed catalyst systems containing a large number of different transition metal compounds can be used to produce polyolefins with specific heterogeneity. This heterogeneity can be intramolecular or intermolecular in nature. For example, mixtures of different transition metal compounds can be used to produce mixtures of polymers with different average molecular weights and / or comonomer contents. For example, mixtures of different transition metal compounds can be used to produce polymers with intramolecular heterogeneity in comonomer content, such as block copolymers. For example, such mixed catalyst systems can be used in a single reactor or in a multistage reactor. For example, when using a multistage reactor, one or more of the compounds of the present invention can be used in only one reactor, and other components of the mixed catalyst system can be added to different reactors in the multistage reactor. The mixed catalyst system may, for example, contain one or more conventional Ziegler-Natta catalysts, Phillips-type chromium catalysts, metallocenes, post-metallocenes, or any other transition metal compounds that catalyze the polymerization of olefins under the applied reaction conditions.

[0040] When polymerization is carried out in a slurry or solution process, the solvent used can be any organic solvent commonly used in olefin polymerization. For example, the solvent can be benzene, toluene, xylene, propane, butane, pentane, hexane, heptane, cyclohexane, methylcyclohexane, and chloromethane. Alternatively, the olefin to be polymerized can be used as the solvent.

[0041] In methods for preparing olefin polymers, polymerization conditions such as temperature, time, pressure, and monomer concentration can be selected within a wide range. Polymerization temperature can, for example, range from -100°C to 300°C, preferably from 0°C to 240°C, more preferably from 50°C to 220°C. Polymerization time can, for example, range from 10 seconds to 20 hours, preferably from 1 minute to 10 hours, more preferably from 3 minutes to 5 hours. In the polymerization of ethylene, ethylene pressure can, for example, range from 1 to 3500 bar, preferably from 1 to 2500 bar, more preferably from 1 to 1000 bar, even more preferably from 1 to 500 bar, and even more preferably from 1 to 100 bar.

[0042] The molecular weight of the polymer can be controlled by known means, such as the use of hydrogen or zinc-alkyl groups in the polymerization. Polymerization can be carried out in batch, semi-continuous, or continuous processes. Polymerization can be carried out in two or more steps under different polymerization conditions. The produced polymer can be separated from the solvent used in the polymerization reaction, as well as from residual monomers and optional comonomers, and dried using methods well known to those skilled in the art.

[0043] In methods for producing olefin polymers using the compounds of the present invention, polymerization may include homopolymerization of an olefin monomer or copolymerization of an olefin monomer with one or more comonomers. The olefin monomer may be, for example, ethylene or propylene. The comonomer may be, for example, ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene; conjugated or non-conjugated dienes such as butadiene, 1,4-hexadiene, substituted or unsubstituted norbornene, 5-ethylidene-2-norbornene, vinyl-norbornene, dicyclopentadiene, 4-methyl-1,4-hexadiene, 1,9-decadiene, or 7-methyl-1,6-octadiene; cyclic olefins such as cyclobutene, cyclopentene; or other olefin compounds such as isobutene, vinyl-cyclohexane, or styrene.

[0044] Preferably, the olefin monomer is ethylene. Polymers produced using ethylene as the olefin monomer can be called ethylene homopolymers, or, if the polymerization is a copolymerization reaction, ethylene copolymers. Such ethylene homopolymers and copolymers can be collectively referred to as polyethylene. For example, terpolymers can also be produced using three monomers; for instance, if a combination of ethylene, propylene, and a third comonomer containing at least two olefin bonds (e.g., norbornene, dicyclopentadiene, ethylene-norbornene, or vinyl-norbornene) is used, a terpolymer that can be called EPDM can be prepared. Preferably, the comonomer is an olefin having three or more carbon atoms, such as an olefin containing 3-10 carbon atoms, for example, an α-olefin containing 3-10 carbon atoms.

[0045] Preferably, the comonomer is selected from propylene, 1-butene, 1-hexene, 1-octene, norbornene, vinyl-cyclohexane, styrene, and 4-methyl-1-pentene. Preferably, the olefin monomer is ethylene, and the comonomer is selected from 1-butene, 1-hexene, 1-octene, norbornene, vinyl-cyclohexane, styrene, and 4-methyl-1-pentene.

[0046] Preferably, the method for producing olefin polymers using the compounds of the present invention is the copolymerization of an olefin monomer with one or more comonomers, wherein the olefin monomer is ethylene, and the comonomer is selected from 1-butene, 1-hexene, 1-octene, norbornene, vinylcyclohexane, styrene, and 4-methyl-1-pentene. Particularly preferably, the method for producing olefin polymers using the compounds of the present invention is the copolymerization of an olefin monomer with one or more comonomers, wherein the olefin monomer is ethylene, and the comonomer is selected from 1-butene, 1-hexene, 4-methyl-1-pentene, vinylcyclohexane, and 1-octene.

[0047] In the case where the polymerization is a copolymerization of an olefin with one or more comonomers, the olefin and the comonomer are different compounds.

[0048] The olefin polymer may, for example, contain 1.0 to 80.0 wt%, preferably 5.0 to 60.0 wt%, more preferably 10.0 to 50.0 wt%, or 10.0 to 30.0 wt%, of a structural portion derived from the comonomer, relative to the total weight of the olefin polymer. The ethylene copolymer may, for example, contain 1.0 to 80.0 wt%, preferably 5.0 to 60.0 wt%, more preferably 10.0 to 50.0 wt%, or 10.0 to 30.0 wt%, of a structural portion derived from the comonomer, relative to the total weight of the ethylene copolymer.

[0049] The polyethylene may, for example, have a melt mass flow rate (MFI 2.16) of ≥0.1 and ≤125 g / 10 min, as determined according to ASTM D1238-10 at 190°C under a load of 2.16 kg. For example, the polyethylene may have an MFI 2.16 of ≥0.1 and ≤50 g / 10 min, or ≥0.3 and ≤10.0 g / 10 min, or ≥0.5 and ≤5.0 g / 10 min.

[0050] The olefin polymer may, for example, have a very high molecular weight, such as ultra-high molecular weight polyolefins, such as ultra-high molecular weight polyethylene, UHMwPE.

[0051] The polyethylene may, for example, have a strength of ≥855 kg / m³ as determined according to ASTM D1505-10. 3 And ≤970kg / m 3 The density of this polyethylene can be, for example, ≥855 and ≤910 kg / m³. 3 or ≥875 and ≤900kg / m 3 The density of this polyethylene can be, for example, ≥910 and ≤925 kg / m³. 3 or ≥910 and ≤920 kg / m 3 or ≥915 and ≤920kg / m 3The density of this polyethylene can be, for example, ≥925 and ≤940 kg / m³. 3 or ≥930 and ≤940 kg / m 3 The density of this polyethylene can be, for example, ≥940 and ≤965 kg / m³. 3 or ≥945 and ≤960kg / m 3 The density.

[0052] It has been found that using the compounds of the present invention, ethylene copolymers in which the comonomer is selected from 1-butene, 1-hexene, 4-methyl-1-pentene, vinyl-cyclohexane, and 1-octene and has a particularly high comonomer incorporation can be produced. The amount of comonomer incorporation can be expressed as the amount of short-chain branches per 1000 carbon atoms in the polymer. The amount of short-chain branches can be, for example, by means of the method described by Randall, Rev. Macromol. Chem. Phys., Vol. 29, Nos. 2 & 3, pp. 285-297. 13 C NMR determination. The ethylene copolymer may, for example, contain at least 10, 25, or 80 short-chain branches per 1000 carbon atoms in the polymer. The ethylene copolymer may contain at most 200, 100, 50, or 25 short-chain branches per 1000 carbon atoms in the polymer. The ethylene copolymer may, for example, contain at least 10 and at most 200 short-chain branches per 1000 carbon atoms in the polymer, or at least 15 and at most 100, or at least 20 and at most 50.

[0053] The polyethylene may have a number-average molecular weight (Mn) of 1,000-10,000,000 g / mol, preferably 10,000-1,000,000 g / mol, more preferably 20,000-500,000 g / mol. The polyethylene may have a weight-average molecular weight (Mw) of 2,000-20,000,000 g / mol, preferably 20,000-2,000,000 g / mol, more preferably 40,000-1,000,000 g / mol. Mw and Mn are determined according to ASTM D6474-12, using 1,2,4-trichlorobenzene or o-dichlorobenzene as a solvent and calibrated with polyethylene or polystyrene standards. The polyethylene may, for example, have a molecular weight distribution Mw / Mn of ≥2.0 and ≤5.0, or ≥2.1 and ≤4.0, or ≥2.5 and ≤3.5.

[0054] The invention will now be illustrated by the following non-limiting examples. In the examples described herein, chemical compounds are synthesized according to the synthetic routes described in WO2021 / 213836, which are further detailed below.

[0055] Synthesis of compound A:

[0056] (A)

[0057] In the first step, a precursor for the linking group used for branching is prepared according to the reaction scheme:

[0058] (I)

[0059] According to the reaction protocol, the precursor obtained from reaction (I) is reacted with 3-(1,1-dimethylethyl)-N-[3'-(1,1-dimethylethyl)-2'-(methoxymethoxy)-5'-methyl[1,1'-biphenyl]-2-yl]-2-(methoxymethoxy)-5-methylaniline (CAS registration number 2798743-40-3):

[0060] (II)

[0061] MOM is the -CH2-O-CH3 structural part.

[0062] The compound obtained from reaction (II) was deprotected from its MOM-protected phenol by using HCl in THF / MeOH to obtain a biphenolic compound. The obtained biphenolic compound was then reacted with tetramethylzirconium in benzene to obtain compound A.

[0063] Similarly, the following compounds were synthesized:

[0064]

[0065] Where Bn represents the benzyl structural part.

[0066] Therefore, the compounds used in the examples correspond to the structures of the compounds of Formula 1 of the present invention according to the structural portions selected according to the Markush structures in the following table:

[0067]

[0068] Where Bn is benzyl, Me is methyl, Ad is adamantyl, and t-Bu is tert-butyl.

[0069] Several polymerization experiments were conducted using the compound defined above to investigate its performance as a catalyst in ethylene polymerization.

[0070] Polymerization was carried out in a parallel pressure reactor (PPR48) for olefin polymerization, which contains 48 reactors housed in a triple glove box and was supplied by Freeslate. The polymerization scheme used is as follows:

[0071] Prior to the execution of the library, 48 PPR units (reactors) underwent a “baking and purging” cycle overnight (8 h at 90–140 °C with intermittent dry N2 streams) to remove any contaminants. After cooling to glove box temperature (23 °C), the stir top was removed, and the unit was fitted with a previously heat-dried disposable 10 ml glass insert and stirrer. The stir top was then returned to its original position, and the unit was loaded with appropriate amounts of toluene (in the range of 2.0–4.0 ml), 1-hexene (in the range of 0.05–2.0 ml), and a triisobutylaluminum (TiBAl) / butylated hydroxytoluene (BHT) reaction product solution, isothermed at the desired polymerization temperature, and pressurized with ethylene to an operating pressure of 1.0 MPa, unless otherwise specified in the examples.

[0072] The catalyst injection sequence is as follows: an appropriate volume of toluene chaser, a solution of the pre-catalyst in toluene (typically in the range of 0.005-0.05 mmol / L), and a toluene buffer are drawn into a slurry needle and then injected into the target unit. The reaction is carried out under constant temperature and pressure with stirring (800 rpm) and continuous ethylene feeding for 5-60 minutes, followed by quenching by overpressurizing the unit with dry air.

[0073] After quenching, the unit was cooled and vented, the stir top was removed, and the glass insert containing the reaction phase was taken out and transferred to a Genevac EZ2-Plus centrifugal evaporator, where all volatiles were distilled off and the resulting polymer was thoroughly dried overnight. The reaction yield was double-checked relative to online monomer conversion measurements by automatically weighing the dried polymer (while still in the reaction vial) in a Bohdan Balance Automator, subtracting the pre-recorded tare weight. Polymer aliquots were then sampled for characterization.

[0074] GPC curves were recorded using a Freeslate Rapid GPC apparatus equipped with a set of two mixed-bed Agilent PLgel 10μm columns and a Polymer Chat IR4 detector. The apparatus's upper deck features a sample dissolution station for up to 48 samples in 10ml magnetically stirred vials, four temperature-controlled chambers each holding 48 polymer solutions in 10ml glass vials, and a dual-arm robot with two heated injection needles. Using the robot, a pre-weighed amount of polymer (typically 1-4 mg) was dissolved in an appropriate volume of o-dichlorobenzene (ODCB) containing 0.40 mg / ml of 2,6-di-tert-butyl-4-methylphenol (BHT) as a stabilizer to obtain solutions with concentrations from 0.5 to 1.0 mg / ml. After gentle stirring at 150°C for 2-4 hours to ensure complete dissolution, the samples were transferred to a temperature-controlled chamber at 145°C and injected sequentially into the system at 145°C and a flow rate of 1.0 ml / min. In post-triggered delayed operation mode, the analysis time for each sample is 12.5 minutes. Calibration is performed using a universal method with 10 monodisperse polystyrene samples (M... n (The concentration ranges from 1.3 to 3700 kg / mol). Before and after each activity, samples from known i-PP batches produced using the bridged ansa-zirconocene catalyst were analyzed for consistency checks.

[0075] Recording was performed using a Bruker Avance 400 III spectrometer equipped with a 5mm high- and low-temperature probe and an automated sample loader with a preheating turntable (24 positions). 13 C10 NMR spectroscopy. Samples (20-30 mg) were dissolved in tetrachloroethane-1,2-d2 (0.6 mL) at 120 °C, with 0.40 mg / mL BHT added as a stabilizer, and loaded onto a turntable maintained at the same temperature. Spectra were acquired sequentially using autotuning, matching, and shimming. Typical operating conditions for routine measurements were: 45° pulse; acquisition time 2.7 sec; relaxation delay 5.0 sec; 400-800 transient scans (corresponding to 30-60 minutes of analysis time). Broadband proton decoupling was achieved using a modified WALTZ16 sequence (Bruker's BI_WALTZ16_32).

[0076] The table below presents the obtained polymers and the properties of the polymerization, where the catalyst activity is expressed as R. p , or polymerization rate, is expressed as the number of kilograms of polymer produced per hour per mmol of catalyst per mol of ethylene in the reactor diluent. n It is the number-average molecular weight expressed in kg / mol. M wIt is the weight-average molecular weight expressed in kg / mol. MWD is the molecular weight distribution M w / M n M is determined according to the GPC method described above. n and M w C6 inc This refers to the amount of 1-hexene incorporated, expressed as mol% of hexene in the copolymer. Experiments were conducted at a total reactor pressure of 0.83 MPa, using the 1-hexene feed concentration (C6) shown in the table. 进料 (in vol% of the feed composition), at 120 °C, N,N'-dimethylphenylammonium tetra(pentafluorophenyl)borate was used as the activator at a molar ratio of 5:1 relative to the transition metal. A solution of triisobutylaluminum / BHT reaction product (1:1 molar ratio) was used, resulting in an aluminum concentration of 2 mmol / L in the reaction unit. In several experiments, diethylzinc was used, as shown in the table below, expressed as mol / mol catalyst.

[0077]

[0078] For comparative purposes, polymerization examples were carried out using the following catalyst compounds according to the methods described above:

[0079]

[0080] The following section presents the results of the polymerization experiment:

[0081]

[0082] As the results presented in the table above indicate, the compounds according to the invention can be used as catalysts in ethylene / 1-hexene copolymerization in which the amount of 1-hexene incorporation is increased.

[0083] Additional experiments were conducted at 150 °C using catalysts D and E, with 2 vol% 1-hexene and 1.48 MPa ethylene pressure in the reactor unit. Other conditions were similar to those described above.

[0084]

[0085] These experiments demonstrate that, even at elevated temperatures, the catalyst of the present invention exhibits good catalytic activity and produces copolymers with very high molecular weights.

Claims

1. Compounds according to Formula 1: Formula 1 in M is a metal atom selected from Hf, Ti, and Zr; X is a halogen, a C1-C4 alkyl moiety, or a benzyl moiety; R1 is a C1-C4 alkyl structural moiety; R2, R3, R4, R5, and R6 may be the same or different; R7 and R8 are each C1-C4 alkyl structural moieties, preferably methyl, and preferably R7 and R8 are the same; and R2, R3, R4, R5, and R6 are each individually selected from hydrogen, C1-C4 alkyl, methoxy, phenyl, benzyl, 2-phenylpropyl, 2,2'-diphenylethyl, 2,4,6-trimethylphenyl, 3,5-dimethylphenyl, 3,5-di-tert-butylphenyl, 9 H -Carbazole-9-yl, 9-methyl-9 H -fluorene-9-yl and adamantyl.

2. The compound according to claim 1, wherein the compound is formulated according to formula 2: Formula 2.

3. The compound according to any one of claims 1-2, wherein M is selected from Hf and Zr.

4. The compound according to any one of claims 1-3, wherein each X is a methyl moiety, a benzyl moiety, or a chlorine atom, preferably wherein two X moietyes are identical.

5. The compound according to any one of claims 1-4, wherein R1 is a methyl moiety.

6. The compound according to any one of claims 1-5, wherein R2 is selected from hydrogen, methyl, methoxy, isobutyl, tert-butyl and adamantyl, preferably selected from methyl, tert-butyl and adamantyl.

7. The compound according to any one of claims 1-6, wherein R3 is selected from hydrogen, methyl, methoxy, tert-butyl and adamantyl, preferably wherein R3 is methyl.

8. The compound according to any one of claims 1-7, wherein R4 is selected from hydrogen, methyl, methoxy, tert-butyl and adamantyl, preferably selected from hydrogen, methoxy and adamantyl.

9. The compound according to any one of claims 1-8, wherein R5 is selected from hydrogen, methyl, methoxy, tert-butyl and adamantyl, preferably wherein R5 is methyl.

10. The compound according to any one of claims 1-9, wherein R6 is selected from hydrogen, methyl, methoxy, tert-butyl and adamantyl, preferably selected from methyl, tert-butyl and adamantyl.

11. A catalyst system comprising the compound according to any one of claims 1-10.

12. The catalyst system according to claim 11, further comprising an activator, wherein the activator is selected from aluminum oxane compounds and boron-based compounds, optionally in the presence of alkyl aluminum compounds.

13. The catalyst system according to claim 12, wherein the aluminoxane compound is selected from methylaluminoxane, isobutylaluminoxane, and methyl-isobutylaluminoxane; or wherein the boron-based compound is selected from tris(pentafluorophenyl)borane and tetra(pentafluorophenyl)borate.

14. The catalyst system according to any one of claims 11-13, wherein the catalyst system comprises a compound according to any one of claims 1-10 supported on a support material, wherein the support material is selected from polymer support materials, clay materials, solid aluminoxanes or inorganic oxides, preferably wherein the support material comprises silica, alumina or solid aluminoxanes.

15. A method for polymerizing olefins, preferably wherein the polymerization comprises reacting a reaction mixture comprising ethylene and / or propylene in the presence of a catalyst system according to any one of claims 11-14, preferably wherein the method is a gas-phase process, a solution process, or a slurry process.

16. The method according to claim 15, wherein the method is a homopolymerization method of ethylene, a homopolymerization method of propylene, a copolymerization method of ethylene and a comonomer, preferably the comonomer is selected from 1-butene, 1-hexene, 4-methyl-1-pentene, vinylcyclohexane and 1-octene, or a copolymerization method of propylene and a comonomer, preferably the comonomer is selected from ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, vinylcyclohexane and 1-octene.

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