Catalytic system comprising a metallocene for the synthesis of polyethylene and ethylene and 1,3-diene copolymer

Abstract

The invention relates to a catalytic system based at least on a borohydrido-neodymocene, a dialkyl zinc compound and an organomagnesium halide of formula RB-Mg-X in which RB comprises a benzene ring of which two carbon atoms are substituted, one of the two being substituted by a methyl, an ethyl or an isopropyl or forming a ring with the carbon atom which is its closest neighbour, the second carbon atom being substituted by a methyl, an ethyl or an isopropyl, the magnesium atom being in the ortho position in relation to each of said two carbon atoms, and X is a halogen atom. The catalytic system can be used both in the homopolymerization of ethylene and in the copolymerization of ethylene and a 1,3-diene.

Description

[0001] Catalytic system comprising a metallocene for the synthesis of polyethylene and ethylene-1,3-diene copolymer.

[0002] The field of the present invention is that of catalytic systems usable in the preparation of polyethylene and copolymer of ethylene and 1,3-diene, in particular polyethylene and copolymer of ethylene and 1,3-diene carrying a ketone function.

[0003] Highly saturated polymers such as polyethylenes and ethylene-rich diene copolymers are essentially hydrocarbon-based and have little affinity for polar materials, which has the consequence of restricting the field of application of these highly saturated hydrocarbon-based polymers. In order to improve this affinity, the introduction of a single or several ketone functions has been described in the case of polyethylenes. For example, the synthesis of ethylene and carbon monoxide copolymers is widely described, but the synthesis process does not apply to copolymers of ethylene and an α-olefin such as a 1,3-diene or a mixture of a 1,3-diene and a vinyl aromatic compound. Furthermore, the synthesis process does not selectively lead to the introduction of a ketone function at the chain end. The introduction of a single ketone function at the chain end of a polyethylene is also described.For example, Polymer Science, Ser. B, Vol. 46, Nos. 9-10, 2004, 308-311 describes the reaction of nitrous oxide and a polyethylene that carries a vinyl group at the chain end. The introduction of the ketone function at the chain end of the polyethylene results from the oxidation reaction of the double bond of the vinyl group by nitrous oxide. Therefore, it appears that the synthesis method is not applicable to the selective chain end functionalization of copolymers of ethylene and a 1,3-diene that contain double bonds also outside the chain ends.

[0004] The Applicants have described, for example, in WO 2007054223 and WO 2007054224 catalyst systems containing a neodymium metallocene and an organomagnesium compound for the synthesis of ethylene and 1,3-butadiene copolymers. The organomagnesium compound is used in the catalyst system as a cocatalyst to activate the metallocene for polymerization. The catalyst systems are useful in the synthesis of both polyethylene and ethylene and 1,3-diene copolymers. The Applicants have also described in WO 2021123589 variants of these catalyst systems in which the organomagnesium compound is a compound of formula R B -Mg- R A , R A being an alkyl, a cycloalkyl or a benzyl, substituted or not, R Bcomprising a benzene ring of which two carbon atoms are substituted, one of the two is substituted by methyl, ethyl or isopropyl or forms a ring with the carbon atom which is its nearest neighbor, the second carbon atom being substituted by methyl, ethyl or isopropyl, the magnesium atom being in the ortho position with respect to each of said two carbon atoms.

[0005] The Applicants, continuing their efforts, have developed a new catalytic system which allows not only the synthesis of polyethylenes and copolymers containing ethylene units and units of a 1,3-diene, but also the selective synthesis of polymers which carry a ketone function, which polymers are polyethylenes and copolymers containing ethylene units and units of a 1,3-diene. The introduction of the ketone function is carried out by reaction of an acid halide with the polymer chains prepared in the presence of the catalytic system in accordance with the invention.

[0006] Thus, a first object of the invention is a catalytic system based on at least: a metallocene of formula (Ia), an organomagnesium halide of formula (IIa), a dialkylzinc,

[0007] {P(Cp 1 )(Cp 2 )Nd(BH4)(i + y)-Ly-N x} (there)

[0008] R B -Mg-X (lia)

[0009] CP 1 and Cp 2 , identical or different, being chosen from the group consisting of fluorenyl groups, cyclopentadienyl groups and indenyl groups, the groups being substituted or unsubstituted,

[0010] Breaking a group bridging the two Cp groups 1 and Cp 2 , and comprising a silicon or carbon atom,

[0011] Nd denoting the neodymium atom,

[0012] L representing an alkali metal chosen from the group consisting of lithium, sodium and potassium,

[0013] N representing a molecule of an ether, x, integer or not, being equal to or greater than 0, y, integer, being equal to or greater than 0

[0014] R Bcomprising a benzene ring of which two carbon atoms are substituted, one of the two is substituted by methyl, ethyl or isopropyl or forms a ring with the carbon atom which is its nearest neighbor, the second carbon atom being substituted by methyl, ethyl or isopropyl, the magnesium atom being in the ortho position with respect to each of said two carbon atoms

[0015] X being a halogen atom.

[0016] The invention also relates to a process for preparing a polymer which comprises the polymerization reaction of ethylene or a monomer mixture containing ethylene and a 1,3-diene in the presence of a catalytic system according to the invention, optionally followed by a modification reaction with an acid halide.

[0017] Detailed description

[0018] Any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​greater than "a" and less than "b" (i.e., excluding the limits a and b), while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​from "a" to "b" (i.e., including the strict limits a and b).

[0019] The compounds mentioned in the description may be of fossil or bio-sourced origin. In the latter case, they may be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass. Similarly, the compounds mentioned may also come from the recycling of materials already in use, that is to say, they may be, partially or totally, derived from a recycling process, or obtained from raw materials themselves derived from a recycling process.

[0020] The expression "based on" used to define the constituents of the catalytic system or catalytic composition means the mixture of these constituents, or the product of the reaction of some or all of these constituents with each other.

[0021] In the present application, metallocene is understood to mean an organometallic complex in which the metal, in this case the rare earth atom, is linked to a ligand molecule consisting of two Cp groups 1 and Cp 2 connected to each other by a P bridge. These Cp groups 1 and Cp 2 , identical or different, are chosen from the group consisting of fluorenyl groups, cyclopentadienyl groups and indenyl groups, these groups being able to be substituted or unsubstituted.

[0022] As substituted cyclopentadienyl, fluorenyl and indenyl groups, mention may be made of those substituted by alkyl radicals having 1 to 6 carbon atoms or by aryl radicals having 6 to 12 carbon atoms or by trialkyl radicals such as SiMes. The choice of radicals is also guided by the accessibility of the corresponding molecules, which are substituted cyclopentadienyl, fluorenyl and indene, because the latter are commercially available or easily synthesized.

[0023] As substituted fluorenyl groups, mention may be made of those substituted in position 2,7, 3 or 6, particularly 2,7-ditertiobutyl-fluorenyl, 3,6-ditertiobutyl-fluorenyl. Positions 2, 3, 6 and 7 respectively designate the position of the carbon atoms of the rings as shown in the diagram below, position 9 corresponding to the carbon atom to which the P bridge is attached.

[0024] As substituted cyclopentadienyl groups, mention may be made of those substituted both in position 2 (or 5) and in position 3 (or 4), particularly those substituted in position 2, more particularly the tetramethylcyclopentadienyl group. Position 2 (or 5) designates the position of the carbon atom which is adjacent to the carbon atom to which the P bridge is attached, as shown in the diagram below.

[0025] As substituted indenyl groups, mention may be made in particular of those substituted in position 2, more particularly 2-methylindenyl, 2-phenylindenyl. Position 2 designates the position of the carbon atom which is adjacent to the carbon atom to which the P bridge is attached, as shown in the diagram below.

[0026] Preferably, Cp 1 and Cp 2are identical and are selected from the group consisting of substituted fluorenyl groups and the unsubstituted fluorenyl group of formula C Hs. Advantageously, Cp 1 and Cp 2 are identical and each represents an unsubstituted fluorenyl group of formula C13H8, represented by the symbol Flu.

[0027] Any ether that has the power to complex the alkali metal is suitable as an ether, especially diethyl ether and tetrahydrofuran.

[0028] The P bridge connecting the Cp groups 1 and Cp 2 preferably responds to the formula ZR 1 R 2 , in which Z represents a silicon or carbon atom, R 1 and R 2 , identical or different, each represent an alkyl group comprising from 1 to 20 carbon atoms, preferably a methyl. In the formula ZR^ 2 , Z advantageously represents a silicon atom, Si.

[0029] The metallocene useful for the synthesis of the catalytic system may be in the form of a crystallized or non-crystalline powder, or in the form of single crystals. The metallocene may be in a monomeric or dimeric form, these forms depending on the method of preparation of the metallocene, as described for example in patent application WO 2007054224 or WO 2007054223. The metallocene may be prepared in a conventional manner by a process analogous to that described in patent application WO 2007054224 or WO 2007054223, in particular by reaction under inert and anhydrous conditions of the salt of an alkali metal of the ligand with a rare earth borohydride in a suitable solvent, such as an ether, such as diethyl ether or tetrahydrofuran or any other solvent known to those skilled in the art. After reaction, the metallocene is separated from the reaction by-products by techniques known to those skilled in the art, such as filtration or precipitation in a second solvent.The metallocene is ultimately dried and isolated in solid form.

[0030] According to a particularly preferred embodiment, the metallocene has the formula in which Flu represents the CisHs group.

[0031] The catalytic system also has as its essential constituent a halide of an organomagnesium of formula (IIa) R B -Mg-X (lia)

[0032] R B comprising a benzene ring of which two carbon atoms are substituted, one of the two is substituted by methyl, ethyl or isopropyl or forms a ring with the carbon atom which is its nearest neighbor, the second carbon atom being substituted by methyl, ethyl or isopropyl, the magnesium atom being in the ortho position with respect to each of said two carbon atoms

[0033] X being a halogen atom. In formula (IIa), X preferably represents a bromine or chlorine atom, more preferably a bromine atom.

[0034] The organomagnesium compound of formula (IIa) is used in the catalytic system as a cocatalyst. Preferably, the two substituents of said two carbon atoms with respect to which the magnesium atom is in the ortho position are identical. More preferably, they are methyl or ethyl. Advantageously, they are methyl.

[0035] Preferably, the organomagnesium compound of formula (IIa) corresponds to formula (IIb) in which X represents a halogen atom, R1 and R5, identical or different, represent a methyl or an ethyl and R2, R3 and R4, identical or different, represent a hydrogen atom or an alkyl. Preferably, R1 and R5 represent a methyl. Preferably, R2 and R4represent a hydrogen atom. In formula (IIb), X preferably represents a bromine or chlorine atom, more preferably a bromine atom.

[0036] According to a preferred variant, R3 is identical to R1 and R5. According to a more preferred variant, R2 and R4 represent a hydrogen and R1, R3 and R5 are identical. In a more preferred variant, R2 and R4 represent a hydrogen and R1, R3 and R5 represent a methyl.

[0037] The catalytic system also has as another essential constituent a zinc compound. The zinc compound is a dialkylzinc compound. In other words, the zinc compound has the formula RzZn in which the symbols R each represent an alkyl. The alkyls of the dialkylzinc compound are preferably alkyls containing 2 to 10 carbon atoms, more preferably ethyl, butyl, octyl. Advantageously, the dialkylzinc compound has the formula (IIIa) ZnR 5 R 6 (Ilia) in which the alkyls represented by the symbols R 5 and R 6 are identical. More preferably, the alkyls represented by the symbols R 5 and R 5 are the same and are ethyl or octyl.

[0038] Preferably, the ratio Nzn / (Nzn + NM Ê) which is the ratio between the number of moles of Zn of the dialkylzinc compound (Nzn) and the sum of the number of moles of Zn of the dialkylzinc compound (Nzn) and the number of moles of Mg of the organomagnesium halide compound (NM6) is greater than 0.05 and less than 0.99. More preferably, this ratio is greater than 0.30 and less than 0.99.

[0039] The catalytic system can be prepared in a traditional manner by a process analogous to that described in patent application WO 2007054224 or WO 2007054223, the organomagnesium halide and the dialkylzinc compound useful for the purposes of the invention being the cocatalysts. For example, in a hydrocarbon solvent, the organomagnesium halide and the zinc compound are brought into contact with the metallocene, typically at a temperature ranging from 20 to 80°C for a period of between 5 and 60 minutes. The quantities of organomagnesium halide, zinc compound and metallocene reacted to form the catalytic system are such that the ratio (NM + Nzn) / NNd, which is the ratio between the sum of the number of moles of Mg in the organomagnesium halide (NM Ê) and the number of moles of Zn in the zinc compound (Nzn) and the number of moles of rare earth metal in the metallocene (NNCI) preferably ranges from 2 to 500, more preferably from 2 to less than 40. The range of values ​​from 2 to less than 40 is particularly more favorable for obtaining polymers with high molar masses.

[0040] The catalyst system is generally in the form of a solution in a hydrocarbon solvent. The hydrocarbon solvent can be aliphatic such as methylcyclohexane or aromatic such as toluene. The hydrocarbon solvent is preferably aliphatic, more preferably methylcyclohexane. Generally, the catalyst system is stored in the form of a solution in the hydrocarbon solvent before being used in polymerization. We can then speak of a catalyst solution which includes the catalyst system and the hydrocarbon solvent. The concentration of the catalyst solution is typically defined by the metallocene metal content in the solution. The metallocene metal concentration has a value preferably ranging from 0.0001 to 0.2 mol L 1 , more preferably from 0.001 to 0.03 mol L 1. Like any synthesis carried out in the presence of organometallic compounds, the synthesis of the catalytic system takes place under anhydrous conditions under an inert atmosphere.

[0041] Typically, reactions are conducted from solvents and anhydrous compounds under anhydrous nitrogen or argon.

[0042] The catalytic system according to the invention is intended to be used in polymer synthesis processes, in particular in the synthesis of polymers containing ethylene, more particularly in the synthesis of polymers containing more than 50 mol% of ethylene.

[0043] A first process for preparing a polymer which in particular allows the preparation of polyethylene comprises the polymerization of ethylene in the presence of a catalytic system in accordance with the invention.

[0044] A second process for preparing a polymer which in particular allows the preparation of a copolymer of ethylene and a 1,3-diene, preferably a random copolymer of ethylene and a 1,3-diene, comprises the polymerization of a monomer mixture containing ethylene and a 1,3-diene in the presence of a catalytic system in accordance with the invention.

[0045] The polymerization reaction common to both processes according to the invention is a polymerization reaction of a monomer, the monomer being ethylene or a monomer mixture containing ethylene and a 1,3-diene. The monomer mixture containing ethylene and a 1,3-diene preferably contains more than 50 mol% of ethylene, molar percentage calculated with respect to the total of the monomers constituting the monomer mixture containing ethylene and a 1,3-diene. The monomer mixture containing ethylene and a 1,3-diene is preferably a mixture of ethylene and a 1,3-diene or a mixture of ethylene, a 1,3-diene and an α-monoolefin. α-monoolefin is understood to mean an α-olefin which has a single carbon-carbon double bond, the double bonds in aromatic compounds not being taken into account. For example, styrene is considered an α-monoolefin. α-Monoolefin is preferably styrene.1,3-diene is a single compound, i.e., a single (in English "one") 1,3-diene, or a mixture of 1,3-dienes that differ from each other in their chemical structure. Suitable 1,3-dienes include 1,3-dienes having 4 to 20 carbon atoms. Preferably, the 1,3-diene is 1,3-butadiene, isoprene, myrcene, 0-farnesene or mixtures thereof such as a mixture of at least two of them. The mixture of at least two of them is advantageously a mixture that contains 1,3-butadiene. The 1,3-diene is preferably 1,3-butadiene or a mixture of 1,3-dienes containing 1,3-butadiene.

[0046] The polymerization is preferably carried out in solution, continuously or discontinuously. The polymerization solvent may be a hydrocarbon, aromatic or aliphatic solvent. Examples of polymerization solvents include toluene and methylcyclohexane. The monomer may be introduced into the reactor containing the polymerization solvent and the catalytic system or, conversely, the catalytic system may be introduced into the reactor containing the polymerization solvent and the monomer. The monomer and the catalytic system may be introduced simultaneously into the reactor containing the polymerization solvent, particularly in the case of continuous polymerization. The polymerization is typically carried out under anhydrous conditions and in the absence of oxygen, in the optional presence of an inert gas. The polymerization temperature generally varies within a range of 40 to 150°C, preferably 40 to 120°C.The person skilled in the art adapts the polymerization conditions such as the polymerization temperature, the concentration of each of the reactants, the pressure in the reactor according to the composition of the monomer mixture, the polymerization reactor, the desired microstructure and macrostructure of the polymer chain. The polymerization is preferably carried out at constant pressure in monomers, in particular at constant ethylene pressure.

[0047] During the polymerization of ethylene and 1,3-dienes in a polymerization reactor, a continuous addition of ethylene and 1,3-dienes may be carried out into the polymerization reactor, in which case the polymerization reactor is a fed reactor. This embodiment is particularly suitable for the synthesis of random copolymer.

[0048] According to one embodiment of the invention, the polymer prepared is a polyethylene.

[0049] According to another embodiment of the invention, the polymer prepared is a copolymer of ethylene and a 1,3-diene, preferably a random copolymer of ethylene and a 1,3-diene.

[0050] According to yet another embodiment of the invention, the polymer prepared is a copolymer of ethylene and 1,3-butadiene, preferably a random copolymer of ethylene and 1,3-butadiene.

[0051] According to any one of the embodiments of the invention, the prepared polymer preferably contains more than 50 mol% of ethylene.

[0052] According to a particularly preferred embodiment of the invention in which the monomer is a monomer mixture containing ethylene and 1,3-butadiene and the ligands of the catalytic system represented by Cp 1 and Cp 2are each an unsubstituted fluorenyl group of formula CIÎHS, the prepared polymer contains in addition to the ethylene monomer units and the butadiene units cyclic units, 1,2-cyclohexane units of the following formula:

[0053] The cyclic units result from a particular insertion of the ethylene and 1,3-butadiene monomers into the polymer chain, in addition to the conventional ethylene and 1,3-butadiene units, respectively -(CH2-CH2)-, -(CH2-CH=CH-CH2)- and -(CH2-CH(C=CH2))-. The mechanism for obtaining such a microstructure is for example described in the document Macromolecules 2009, 42, 3774-3779. When the polymer in accordance with the invention contains 1,2-cyclohexane units, it preferably contains at most 15 mol% thereof, the percentage being expressed relative to all the repeating units constituting the polymer.

[0054] According to a first variant of the invention, the polymerization is stopped, for example by cooling the polymerization medium or by adding an alcohol, preferably an alcohol containing 1 to 3 carbon atoms, for example ethanol. The polymer can be recovered according to conventional techniques known to those skilled in the art, such as for example by precipitation, by evaporation of the solvent under reduced pressure or by stripping with water vapor.

[0055] In a second variant, the polymerization reaction is followed by a modification reaction with an acid halide to introduce a ketone function into the polymer. As is well known, acid halides, also called acyl halides, are halogenated derivatives of carboxylic acids in which the OH group of the carboxylic acid function COOH is substituted by a halogen atom. Acid halides are therefore compounds that contain one or more COX groups.1 , X 1 denoting a halogen atom.

[0056] Before adding the acid halide, the reactor is preferably degassed and inerted. Degassing the reactor removes residual gaseous monomers and also facilitates the addition of the acid halide to the reactor. Alternatively, the acid halide can be injected into the reactor by overpressure. Inerting the reactor, for example with nitrogen, prevents the deactivation of the carbon-metal bonds present in the reaction medium and necessary for the reaction of the acid halide with the polymer chains formed during the polymerization reaction. The acid halide can be added neat or diluted in a hydrocarbon solvent, preferably aliphatic such as methylcyclohexane or aromatic such as toluene. The acid halide is left in contact with the polymer chains for the time required for the reaction between the acid halide and the polymer chains produced in the previous step, the polymerization reaction.The reaction between the acid halide and the polymer chains can typically be followed by chromatographic analysis to monitor the consumption of the acid halide. It is preferably carried out at a temperature ranging from 23 to 120 °C, for 1 to 60 minutes with stirring. The modification reaction is preferably carried out with one molar equivalent of COX group. 1 relative to the total number of carbon-magnesium bonds per mole of magnesium compound and carbon-zinc bonds per mole of zinc compound in the catalytic system. The ratio between the number of molar equivalents of COX group 1and the total number of carbon-magnesium bonds per mole of co-catalyst and carbon-zinc bonds per mole of zinc compound can, however, vary widely, for example from 0.1 to 10, depending on the desired level of ketone-functional polymer in the prepared polymer. A ratio close to 1, typically ranging from 0.85 to 1.05, favors the highest ketone functional levels. The acid halide may contain one or more COX groups 1 , X 1 denoting a halogen atom. The acid halide may be an aliphatic or aromatic compound. An aromatic acid halide is preferred from the point of view of characterizing the modified polymer, in particular by highlighting the aromatic ring in the modified polymer by nuclear magnetic resonance analysis. Preferably, the acid halide has the formula Ar-fCOX 1)^ Ar representing an aromatic cycle, preferably a benzene cycle, n an integer equal to 1, 2 or 3, X 1 a halogen atom. The aromatic ring, in particular benzene, may carry one or more substituents other than the COX groups 1 . Suitable for this purpose are 4-methoxybenzoyl chloride, p-toluoyl chloride, 4-iodobenzoyl chloride, 4-bromobenzoyl chloride, 4-nitrobenzoyl chloride, 4-methoxy benzoyl chloride, 4-(methoxymethyl)benzoyl chloride, 3-methoxy-benzoyl bromide, 4-(dimethylamino)benzoyl chloride, 4-[(dimethylamino)methyl]benzoyl chloride, 4-[2-(dimethylamino)ethyl]benzoyl chloride, trimesoyl chloride, 5-methoxy-1,3-benzenedicarbonyl dichloride, benzoyl bromide, isophthaloyl dichloride, terephthaloyl chloride.

[0057] Acid halides having a single COX group 1provide access to polymers carrying a ketone function at the chain end. Acid halides having two COX groups 1 can lead to coupled polymers that result from the coupling between two polymer chains. Acid halides having more than two COX groups 1 , can lead to star polymers which result from the coupling between at least three polymer chains.

[0058] According to any embodiment of the invention, the acid halide is advantageously an acid chloride, in which case the COX group 1 is the COCI group.

[0059] Once the polymer chains have been modified, an additional step can be carried out to deactivate the reactive sites still present in the reaction medium, for example by adding a terminating agent to the reaction medium or by pouring the reaction medium onto a solution containing the terminating agent. The terminating agent is generally in stoichiometric excess. The terminating agent is typically a protic compound, a compound which has a relatively acidic proton. Examples of terminating agents include water, carboxylic acids, in particular C2-C18 fatty acids such as acetic acid, stearic acid, aliphatic or aromatic alcohols, such as methanol, ethanol, isopropanol, and phenolic antioxidants.The modified polymer can be separated from the reaction medium according to methods well known to those skilled in the art, for example by an operation of evaporation of the solvent under reduced pressure, by precipitation or by a steam stripping operation.

[0060] The polymer prepared according to the second variant preferably carries one or more ketone functions at the chain end. The modification reaction for introducing a ketone function into the polymers prepared in the presence of a catalytic system in accordance with the invention is highly selective. The selectivity rate of the modification reaction reaches 100% or almost 100% in ketone function. Furthermore, the levels of modified chains are also high, generally at least 50%. They are typically much higher than 50%, typically at least 80% in the case of the preparation of modified polyethylenes.

[0061] In summary, the invention is advantageously implemented according to any one of the following embodiments 1 to 28:

[0062] Mode 1: Catalytic system based on at least: a metallocene of formula (Ia), an organomagnesium halide of formula (IIa), a dialkylzinc compound,

[0063] {P(Cp 1 )(Cp 2 )Nd(BH4)(i + y)-Ly-N x} (there)

[0064] R B -Mg-X (lia)

[0065] CP 1 and Cp 2 , identical or different, being chosen from the group consisting of fluorenyl groups, cyclopentadienyl groups and indenyl groups, the groups being substituted or unsubstituted,

[0066] Breaking a group bridging the two Cp groups 1 and Cp 2 , and comprising a silicon or carbon atom,

[0067] Nd denoting the neodymium atom,

[0068] L representing an alkali metal chosen from the group consisting of lithium, sodium and potassium,

[0069] N representing a molecule of an ether, x, integer or not, being equal to or greater than 0, y, integer, being equal to or greater than 0

[0070] R B comprising a benzene ring of which two carbon atoms are substituted, one of the two is substituted by methyl, ethyl or isopropyl or forms a ring with the carbon atom which is its nearest neighbor, the second carbon atom being substituted by methyl, ethyl or isopropyl, the magnesium atom being in the ortho position with respect to each of said two carbon atoms

[0071] X being a halogen atom.

[0072] Mode 2: Catalytic system according to mode 1 in which Cp 1 and Cp 2are identical and are selected from the group consisting of substituted fluorenyl groups and the unsubstituted fluorenyl group of formula CisHs.

[0073] Mode 3: Catalytic system according to mode 1 or 2 in which Cp 1 and Cp 2 each represent an unsubstituted fluorenyl group of formula CisHg.

[0074] Mode 4: Catalytic system according to any one of modes 1 to 3 in which the P bridge connecting the Cp groups 1 and Cp 2 responds to the formula ZR 1 R 2 , in which Z represents a silicon or carbon atom, R 1 and R 2 , identical or different, each represent an alkyl group comprising from 1 to 20 carbon atoms.

[0075] Mode 5: Catalytic system according to mode 4 in which R 1 and R 2each represent a methyl. Mode 6: Catalytic system according to mode 4 or 5 in which Z represents a silicon atom.

[0076] Mode 7: Catalytic system according to any one of modes 1 to 6 in which the metallocene is of formula (111-1), (111-2), (111-3), (111-4) or (111-5): [Me2Si(Flu)2Nd(n-BH4)2Li(THF)] (lll-l)

[0077] [{Me2SiFlu2Nd(pi-BH4)2Li(THF)}2] (IH-2)

[0078] [Me2SiFlu2Nd(p-BH4)(THF)] (111-3)

[0079] [{Me2SiFlu2Nd(p-BH4)(THF)}2] (111-4)

[0080] [Me2SiFlu2Nd(n-BH4)] (111-5) in which Flu represents the CisHs group.

[0081] Mode 8: Catalytic system according to any one of modes 1 to 7 in which the alkyls of the dialkylzinc are alkyls containing 2 to 10 carbon atoms.

[0082] Mode 9: Catalytic system according to any one of modes 1 to 8 in which the dialkylzinc compound is of formula (Ilia)

[0083] ZnR5 R 5 (Ilia) in which the alkyls represented by the symbols R 5 and R 6 are identical.

[0084] Mode 10: Catalytic system according to mode 9 in which the alkyls represented by the symbols R 5 and R 6 are ethyl or octyl.

[0085] Mode 11: Catalytic system according to any one of modes 1 to 10 in which the organomagnesium halide is of formula (II b) in which X represents a halogen atom, R1 and Rs, identical or different, represent a methyl or an ethyl and R2, Rs and R4, identical or different, represent a hydrogen atom or an alkyl.

[0086] Mode 12: Catalytic system according to mode 11 in which Rs is identical to Ri and Rs.

[0087] Mode 13: Catalytic system according to mode 11 or 12 in which Ri and Rs represent a methyl

[0088] Mode 14: Catalytic system according to any one of modes 11 to 13 in which R2 and R4 represent a hydrogen atom.

[0089] Mode 15: Catalytic system according to any one of modes 1 to 14 in which X is a chlorine or bromine atom. Mode 16: Catalytic system according to any one of modes 1 to 15 in which X is a bromine atom.

[0090] Mode 17: Catalytic system according to any one of modes 1 to 16 in which the ratio between the number of moles of Zn of the dialkylzinc compound and the sum of the number of moles of Zn of the dialkylzinc compound and the number of moles of Mg of the organomagnesium halide compound is greater than 0.05 and less than 0.99.

[0091] Mode 18: Catalytic system according to any one of modes 1 to 17 in which the ratio between the number of moles of Zn of the dialkylzinc compound and the sum of the number of moles of Zn of the dialkylzinc compound and the number of moles of Mg of the organomagnesium halide compound is greater than 0.3 and less than 0.99.

[0092] Mode 19: Catalytic system according to any one of modes 1 to 18 in which the ratio between the sum of the number of moles of Mg of the organomagnesium halide and the number of moles of Zn of the zinc compound and the number of moles of rare earth metal of the metallocene ranges from 2 to 500.

[0093] Mode 20: Catalytic system according to any one of modes 1 to 19 in which the ratio between the sum of the number of moles of Mg of the organomagnesium halide and the number of moles of Zn of the zinc compound and the number of moles of rare earth metal of the metallocene ranges from 2 to less than 40.

[0094] Method 21: A process for preparing a polymer which comprises the polymerization reaction of ethylene or a monomer mixture containing ethylene and a 1,3-diene in the presence of a catalyst system defined in any one of methods 1 to 20.

[0095] Method 22: Preparation process according to method 21 in which the polymerization reaction is followed by a modification reaction with an acid halide.

[0096] Method 23: Preparation process according to method 22 in which the acid halide is of formula Ar-(COX 1 ) n , Ar representing an aromatic cycle, preferably a benzene cycle, n an integer equal to 1, 2 or 3, X 1 a halogen atom.

[0097] Method 24: Preparation process according to any one of methods 22 to 23 in which the acid halide is an acid chloride.

[0098] Method 25: Preparation process according to any one of methods 21 to 24 in which the polymer is a polyethylene or a copolymer of ethylene and a 1,3-diene.

[0099] Method 26: Preparation process according to method 25 in which the copolymer of ethylene and a 1,3-diene is a random copolymer of ethylene and a 1,3-diene.

[0100] Method 27: Preparation process according to any one of methods 21 to 26 in which the 1,3-diene is 1,3-butadiene, isoprene, myrcene, P-farnesene or mixtures thereof.

[0101] Mode 28: Preparation process according to any one of modes 21 to 27 in which the 1,3-diene is 1,3-butadiene or a mixture of 1,3-dienes containing 1,3-butadiene. The above-mentioned characteristics of the present invention, as well as others, will be better understood on reading the following description of the exemplary embodiments of the invention, given for illustrative and non-limiting purposes.

[0102] Examples

[0103] Ethylene homopolymers and ethylene-butadiene copolymers were prepared using the metallocene {(Me2Si(Ci3Hg)2)Nd(p-BH4)[(p-BH4)Li(THF)]}2 prepared according to the procedure described in patent application WO 2007054224. The organomagnesium and zinc compounds are commercial products. Unless otherwise indicated, the following are used: butyloctylmagnesium in solution in heptane at 0.88 mol L 1 from Chemtura; diethylzinc in hexane solution at 1 mol L 1 from Sigma-Aldrich; mesitylmagnesium bromide in diethyl ether at 1 mol L 1 from Sigma-Aldrich.

[0104] The polymers were characterized using the methods described below.

[0105] The ethylene, N35 grade, comes from Air Liquide and is used without prior purification.

[0106] 1,3-Butadiene is purified on alumina guards.

[0107] The toluene solvent from BioSolve is dried and purified on an alumina column in a solvent fountain from mBraun and used under an inert atmosphere.

[0108] All reactions are carried out under an inert atmosphere.

[0109] High-temperature size exclusion chromatography (HT-SEC) for polyethylenes: High-temperature size exclusion chromatography (HT-SEC) analyses were performed using a Viscotek instrument (Malvern Instruments) equipped with 3 columns (PLgel Olexis 300 mm x 7 mm ID from Agilent Technologies) and 3 detectors (refractometer, differential viscometer and light scattering). 200 pL of a sample solution at a concentration of 8 mg mL 1 were eluted in 1,2,4-trichlorobenzene using a flow rate of 1 mL min 1 at 150 °C. The mobile phase was stabilized with 2,6-di(tert-butyl)-4-methylphenol (400 mg L x). OmniSEC software was used for data acquisition and analysis. The number-average molar masses (M n ) and in mass (M w ) of synthesized polyethylenes were calculated using a calibration curve obtained from standard polyethylenes (M p : 338, 507, 770, 1,890, 17,000, Tl 300, 43,400, 53,100, 65,700, 78,400 g mol -1 ) from Polymer Standards Service (Mainz).

[0110] THF size exclusion chromatography (SEC-THF) for ethylene and 1,3-butadiene copolymers:

[0111] Size exclusion chromatography analyses were performed using a Viscotek apparatus (Malvern Instruments) equipped with 3 columns (SDVB, 5 μm, 300 x 7.5 mm from Polymer Standards Service), a guard column and 3 detectors (refractometer, differential viscometer and light scattering). 1 mL of a sample solution with a concentration of 5 mg mL 1in THF was filtered through a 0.45 μm PTFE membrane. 100 pL of this solution was eluted in THF using a flow rate of 0.8 mL min 1 at a temperature of 35 °C. OmniSEC software was used for data acquisition and analysis. The number-averaged molar masses (M n ) and in mass (A W ) of synthesized ethylene and butadiene copolymers were calculated using a universal calibration curve obtained from standard polystyrenes (M p 1,306 to 2,520,000 g mol 1 ) from Polymer Standards Service (Mainz).

[0112] Nuclear Magnetic Resonance (NMR):

[0113] High-resolution NMR spectroscopy of the polymers was performed on a Bruker 400 Avance III spectrometer operating at 400 MHz equipped with a 5 mm BBFO proton probe and on a Bruker 400 Avance II spectrometer operating at 400 MHz equipped with a PSEX probe. 13C 10 mm for carbon. Acquisitions were made in a mixture of tetrachloroethylene (TCE) and deuterated benzene (CeDe) (2 / 1 v / v) at 363 K for ethylene homopolymers, and in deuterated chloroform (CDCH) at 298 K for ethylene and butadiene copolymers. Samples were analyzed at a concentration of 1% by mass for the proton and 5% by mass for carbon. Chemical shifts are given in ppm, relative to the proton signal of deuterated benzene set at 7.16 ppm (respectively of deuterated chloroform at 7.26 ppm) and to the carbon signal of TCE set at 120.65 ppm. magnesium being the co-catalyst, and functionalization with 4-me chloride nzoyle (example not in accordance with the invention):

[0114] 192 mL of toluene taken from the solvent fountain (SPS800 MBraun) are introduced into a 250 mL inerted flask equipped with a magnetic olive. 2.27 mL of butyloctylmagnesium in heptane (0.88 mol L_1 ) and 4 mL diethyl ether (38.5 mmol) are introduced into the flask with stirring. 8.3 mg (13 pmoles in neodymium) of {(Me2Si(Ci3Hg)2)Nd(p-BH4)[(p- BH4)Li(TH F)]}2 are then introduced into the flask. The catalytic solution is transferred using a cannula into a 250 mL reactor under an inert atmosphere. The pressure in the reactor is reduced to 0.5 bar and then the reactor is pressurized to 4 bar of ethylene (absolute pressure) and the temperature is simultaneously brought to 80 °C. The pressure is kept constant in the reactor using a tank containing ethylene. When the desired amount of ethylene has been consumed, i.e. after 26 min, the reactor is degassed and 10 mL (5%) of the polymer solution is cannulated out of the reactor, then the polymer is precipitated in methanol, recovered by filtration and dried.

[0115] 10 mL of a degassed and molecular sieve-stored solution of 0.57 M 4-methoxybenzoyl chloride in toluene (5.7 mmol, 2 equivalent / Mg) is added to the polymer solution remaining in the reactor. After stirring for 1 h at 80 °C, the polymer solution is poured onto methanol with stirring to precipitate the polymer. The polymer with the modifying agent is filtered, washed with methanol, then dried and characterized. 4.3 g of polyethylene is recovered (activity of 750 Kg / mol / h) with a number-average molar mass of 1400 g mol 1 and a dispersity of 1.4 and 55% of the chains are functional. The 55% of the functional chains are distributed into 11% in the form of secondary alcohol and 44% in the form of tertiary alcohol. polyethylene, diethylzinc and mesitylmagnesium bromide being the co-i bears functionalization with 4-me chloride example in accordance with i

[0116] 196 mL of toluene taken from the solvent fountain (SPS800 MBraun) are introduced into an inerted 250 mL flask equipped with a magnetic olive. 0.5 mL of mesitylmagnesium bromide in diethyl ether (0.5 mol L -1 ) and 1 mL of diethylzinc in hexane (1 mol L -1) are introduced into the flask with stirring. 7.7 mg (12 pmoles of neodymium) of {(Me2Si(Ci3H8)2)Nd(p-BH4)[(Li-BH4)Li(THF)]}2 are then introduced into the flask. The catalytic solution is transferred using a cannula into a 250 mL reactor under an inert atmosphere. The pressure in the reactor is reduced to 0.5 bar and then the reactor is pressurized to 4 bar of ethylene and the temperature is simultaneously brought to 80 °C. The pressure is kept constant in the reactor using a tank containing ethylene. When the desired amount of ethylene has been consumed, i.e. after 31 min, the reactor is degassed and 10 mL (5%) of the polymer solution is transferred using a cannula out of the reactor, then the polymer is precipitated in methanol, recovered by filtration and dried.10 mL of a degassed and sieve-stored solution of 0.23 M 4-methoxybenzoyl chloride in toluene (2.3 mmol, 1 equivalent / Mg + 2 equivalent / Zn) is added to the polymer solution remaining in the reactor. After stirring for 1 h at 80 °C, the polymer solution is poured onto methanol with stirring to precipitate the polymer. The polymer is filtered, washed with methanol, then dried and characterized. 4.2 g of polyethylene is recovered (activity of 690 kg / mol / h) with a number-average molar mass of 2000 g mol. 1 and a dispersity of 1.1 and 79% of the chains are functional and carry a ketone, i.e. a selectivity of the functionalization reaction of 100%.

[0117] Example 3: Synthesis of ene, diethylzinc and mesin bromide um being the co-catalysts, then functionalization with 4-dimethylaminobenzoyl chloride (example in accordance with the invention):

[0118] 196 mL of toluene taken from the solvent fountain (SPS800 MBraun) are introduced into an inerted 250 mL flask equipped with a magnetic olive. 0.4 mL of mesitylmagnesium bromide in diethyl ether (0.5 mol L -1 ) and 1 mL of diethylzinc in heptane (1 mol L -1) are introduced into the flask with stirring. 7.7 mg (12 pmoles of neodymium) of {(Me2Si(Ci3H8)2)Nd(p-BH4)[(p-BH4)Li(THF)]}2 are then introduced into the flask. The catalytic solution is transferred using a cannula into a 250 mL reactor under an inert atmosphere. The pressure in the reactor is reduced to 0.5 bar and then the reactor is pressurized to 4 bar of ethylene and the temperature is simultaneously brought to 80 °C. The pressure is kept constant in the reactor using a tank containing ethylene. When the desired amount of ethylene has been consumed, i.e. after 17 min, the reactor is degassed and 10 mL (5%) of the polymer solution is transferred using a cannula out of the reactor, then the polymer is precipitated in methanol, recovered by filtration and dried. 7.8 mL of a degassed and stored solution on molecular sieve of 4-dimethylaminobenzoyl chloride at 0.23 M in toluene (1.8 mmol, 1 equivalent / Mg + 2 equivalent / Zn) is added to the polymer solution remaining in the reactor. After 1 h of stirring at 80 °C, the polymer solution is poured onto methanol with stirring to precipitate the polymer. The polymer is filtered, washed with methanol, then dried and characterized. 3.7 g of polyethylene is recovered (activity of 980 Kg / mol / h) with a number average molar mass of 2100 g mol. 1 and a dispersity of 1.1. 50% of the chains are functional and carry a ketone, i.e. a selectivity of the functionalization reaction of 100%.

[0119] Example 4: Synthesis of poly(ethylene-co-butadiene), diethylzinc and mesitylmagnesium bromide being the co-catalysts, then functionalization with 4-methoxybenzoyl chloride (example in accordance with the invention):

[0120] 198 mL of toluene taken from the solvent fountain (SPS800 MBraun) are introduced into a 250 mL inerted flask equipped with a magnetic olive. 0.8 mL of mesitylmagnesium bromide in diethyl ether (0.5 mol L -1 ) and 0.5 mL of diethylzinc in heptane (1 mol L 1) are introduced into the flask with stirring. 32 mg (50 pmoles of neodymium) of {(Me2Si(Ci3H8)2)Nd(p-BH4)[(p-BH4)Li(THF)]}2 are then introduced into the flask. The catalytic solution is transferred using a cannula into a 250 mL reactor under an inert atmosphere. The pressure in the reactor is reduced to 0.5 bar and then the reactor is pressurized to 4 bar of ethylene and the temperature is simultaneously brought to 80 °C. The pressure is kept constant in the reactor using a tank containing a gaseous mixture of ethylene / butadiene at 80 / 20 mol / moL. When the desired quantity of monomers has been consumed, i.e. after 115 min, the reactor is degassed and 10 mL (5%) of the polymer solution is transferred using a cannula out of the reactor, then the polymer is precipitated in methanol, recovered by filtration and dried.

[0121] 10 mL of a degassed and molecular sieve-stored solution of 0.14 M 4-methoxybenzoyl chloride in toluene (1.4 mmol, 1 equivalent / Mg + 2 equivalent / Zn) is added to the polymer solution remaining in the reactor. After stirring for 1 h at 80 °C, the polymer solution is poured onto methanol with stirring to precipitate the polymer. The polymer is filtered, washed with methanol, then dried and characterized. 7.2 g of poly(ethylene-co-butadiene) is recovered (activity of 75 kg / mol / h) with a number-average molar mass of 12600 g mol 1 and a dispersity of 1.3. 38% of the chains are functional and carry a ketone, i.e. a selectivity of the functionalization reaction of 100%.

[0122] Example 5: Synthesis of ene-co-l diethylzinc and mesitylmagnesium bromide being the co-catalysts, then functionalization with 4-dimethylaminobenzoyl chloride (example in accordance with the invention):

[0123] 198 mL of toluene taken from the solvent fountain (SPS800 MBraun) are introduced into a 250 mL inerted flask equipped with a magnetic olive. 1.6 mL of mesitylmagnesium bromide in diethyl ether (0.5 mol L -1 ) and 1 mL of diethylzinc in heptane (1 mol L -1) are introduced into the flask with stirring. 32 mg (50 pmoles of neodymium) of {(Me2Si(Ci3H8)2)Nd(p-BH4)[(p-BH4)Li(THF)]}2 are then introduced into the flask. The catalytic solution is cannulated into a 250 mL reactor under an inert atmosphere. The pressure in the reactor is reduced to 0.5 bar and then the reactor is pressurized to 4 bars of ethylene and the temperature is simultaneously brought to 80 °C. The pressure is kept constant in the reactor using a tank containing a gaseous mixture of ethylene / butadiene at 80 / 20 mol / moL. When the desired quantity of monomers has been consumed, i.e. after 174 min, the reactor is degassed and 10 mL (5%) of the polymer solution is transferred using a cannula out of the reactor, then the polymer is precipitated in methanol, recovered by filtration and dried.20 mL of a degassed and molecular sieve-stored solution of 0.14 M 4-dimethylaminobenzoyl chloride in toluene (2.8 mmol, 1 equivalent / Mg + 2 equivalent / Zn) is added to the polymer solution remaining in the reactor. After stirring for 1 h at 80 °C, the polymer solution is poured onto methanol with stirring to precipitate the polymer. The polymer is filtered, washed with methanol, then dried and characterized. 10.3 g of poly(ethylene-co-butadiene) is recovered (activity of 70 kg / mol / h) with a number-average molar mass of 16400 g mol. 1 and a dispersity of 1.3. 35% of the chains are functional and carry a ketone, i.e. a selectivity of the functionalization reaction of 100%.

[0124] The examples show that the catalytic system which contains both an organomagnesium halide of formula (IIa) and a dialkylzinc compound allows not only the synthesis of polyethylenes and copolymers containing ethylene units and units of a 1,3-diene, but also the selective synthesis of polyethylenes and copolymers containing ethylene units and units of a 1,3-diene, which polyethylenes and copolymers carry a ketone function.

[0125] The catalytic system according to the invention is as versatile as the catalytic system devoid of zinc compound: like the catalytic system devoid of zinc compound, it allows the production of both polyethylenes and copolymers of ethylene and 1,3-diene, in this case 1,3-butadiene.

Claims

Claims 1. Catalytic system based on at least: a metallocene of formula (Ia), an organomagnesium halide of formula (IIa), a dialkylzinc compound, {P(Cp 1 )(Cp 2 )Nd(BH4)(i+y)-Ly-N x} (there) R B -Mg-X (lia) CP 1 and Cp 2 , identical or different, being chosen from the group consisting of fluorenyl groups, cyclopentadienyl groups and indenyl groups, the groups being substituted or unsubstituted. Breaking a group bridging the two Cp groups 1 and Cp 2 , and comprising a silicon or carbon atom, Nd denoting the neodymium atom, L representing an alkali metal chosen from the group consisting of lithium, sodium and potassium, N representing a molecule of an ether, x, integer or not, being equal to or greater than 0, y, integer, being equal to or greater than 0 R B comprising a benzene ring of which two carbon atoms are substituted, one of the two is substituted by methyl, ethyl or isopropyl or forms a ring with the carbon atom which is its nearest neighbor, the second carbon atom being substituted by methyl, ethyl or isopropyl, the magnesium atom being in the ortho position with respect to each of said two carbon atoms X being a halogen atom.

2. Catalytic system according to claim 1 in which Cp 1 and Cp 2 are identical and are chosen from the group consisting of substituted fluorenyl groups and the unsubstituted fluorenyl group of formula C11H5, preferably each represent an unsubstituted fluorenyl group of formula C11H5.

3. Catalytic system according to any one of claims 1 to 2 in which the bridge P connecting the Cp groups 1 and Cp 2responds to the formula ZR^ 2 , in which Z represents a silicon or carbon atom, R 1 and R 2 , identical or different, each represent an alkyl group comprising from 1 to 20 carbon atoms, preferably a methyl.

4. Catalytic system according to any one of claims 1 to 3 in which the alkyls of the dialkylzinc are alkyls containing 2 to 10 carbon atoms.

5. Catalytic system according to any one of claims 1 to 4 in which the dialkylzinc compound is of formula (IIIa) ZnR 5 R 6 (Ilia) in which the alkyls represented by the symbols R 5 and R 6 are identical, preferably ethyl or octyl.

6. Catalytic system according to any one of claims 1 to 5 in which the organomagnesium halide is of formula (IIb) in which X represents a halogen atom, R1 and Rs, identical or different, represent a methyl or an ethyl and R2, R3 and R4, identical or different, represent a hydrogen atom or an alkyl.

7. Catalytic system according to claim 6 in which R3 is identical to R1 and R5.

8. Catalytic system according to claim 6 or 7 in which R1 and R5 represent a methyl 9. Catalytic system according to any one of claims 6 to 8 in which R2 and R4 represent a hydrogen atom.

10. Catalytic system according to any one of claims 1 to 9 in which X is a chlorine or bromine atom, preferably a bromine atom.

11. Catalytic system according to any one of claims 1 to 10 in which the ratio between the number of moles of Zn of the dialkylzinc compound and the sum of the number of moles of Zn of the dialkylzinc compound and the number of moles of Mg of the organomagnesium halide compound is greater than 0.05 and less than 0.99, more preferably greater than 0.3 and less than 0.

99.

12. A process for preparing a polymer which comprises the polymerization reaction of ethylene or a monomer mixture containing ethylene and a 1,3-diene in the presence of a catalytic system defined in any one of claims 1 to 11.

13. Preparation process according to claim 12 in which the polymerization reaction is followed by a modification reaction with an acid halide, preferably an acid chloride.

14. Preparation process according to claim 12 or 13 in which the polymer is a polyethylene or a copolymer of ethylene and a 1,3-diene, preferably a random copolymer of ethylene and a 1,3-diene.

15. Preparation process according to any one of claims 12 to 14 in which the 1,3-diene is 1,3-butadiene, isoprene, myrcene, p-farnesene or mixtures thereof, preferably 1,3-butadiene or a mixture of 1,3-dienes containing 1,3-butadiene.

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