Process for the synthesis of polyethylenes or copolymers of ethylene and 1,3-diene bearing a terminal ketone function.

Abstract

The invention relates to a process for preparing a polyethylene bearing a terminal ketone function or a copolymer of ethylene and a 1,3-diene and optionally a vinylaromatic compound which contains more than 50 mole percent of ethylene and which bears a terminal ketone function, which process comprises a polymerization reaction of the monomers in the presence of a neodymocene borohydrido complex and an organomagnesium compound, followed by a coupling reaction with a compound having a nitrile function, and then a hydrolysis reaction.

Description

Title of the invention: Process for the synthesis of polyethylenes or copolymers of ethylene and 1,3-diene bearing a terminal ketone function.

[0001] The field of the invention is that of polyethylenes and ethylene and α-olefin copolymers which are rich in ethylene units and which are functionalized at the end of the chain by a polar function, a ketone.

[0002] The synthesis of polyethylenes and α-olefin copolymers is widely described in scientific literature. It is well known that the choice of polymerization route will determine the polymer chain structure. Polymerization by means of a coordination catalysis that utilizes certain neodymium-based metallocenes can lead to the production of polyethylenes and ethylene-rich diene copolymers that contain more than 50 mol% ethylene units, as described, for example, in WO 2014114607 AL. In particular, copolymers containing ethylene and diene units are synthesized by a polymerization mechanism involving highly specific reactive species and numerous transfer reactions, as described, for example, in ACS Catalysis, 2016, Volume 6, Issue 2, pages 1028-1036.

[0003] Highly saturated polymers such as polyethylenes and diene copolymers rich in ethylene units are essentially hydrocarbons and exhibit little affinity for polar materials, which consequently restricts the range of applications for these highly saturated hydrocarbon polymers. To improve this affinity, the introduction of one or more ketone groups 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 is not applicable to copolymers of ethylene and an α-olefin such as a 1,3-diene or a mixture of a 1,3-diene and a vinylaromatic compound. Furthermore, the synthesis process does not selectively lead to the introduction of a ketone group at the chain end. The introduction of a single ketone group at the chain end of a polyethylene is also described.For example, the document Polymer Science, Ser. B, Vol. 46, Nos. 9-10, 2004, 308-311 describes the reaction of nitrous oxide and a polyethylene bearing a vinyl group at its chain end. The introduction of the ketone function at the polyethylene chain end results from the oxidation reaction of the vinyl group's double bond by nitrous oxide. Therefore, it appears that the synthesis process is not applicable to the selective chain-end functionalization of ethylene copolymers and a 1,3-diene. contain double bonds even outside the ends of the chain.

[0004] Finally, the methods described for introducing ketone functions also do not allow for the simultaneous introduction of a second function other than a ketone function. For this, they must resort to the use of an additional functionalizing agent.

[0005] The Applicants have developed a process for introducing a ketone function at the end of a polymer chain, applicable to both polyethylenes and ethylene-rich diene copolymers, such as copolymers of ethylene and a 1,3-diene or a copolymer of ethylene, a 1,3-diene, and a vinylaromatic compound. Furthermore, the process is perfectly suited for introducing two functions simultaneously: a ketone function and a second function other than a ketone, without the need for an additional functionalizing agent.

[0006] A first object of the invention is a process for preparing a polymer containing more than 50% by mole of ethylene units and bearing a ketone function at one of its chain ends, which process comprises the successive steps a), b) and c) - step a) being the polymerization of a monomer mixture containing ethylene in the presence of a catalytic system based on at least one metallocene of formula (I) and an organomagnesium {P(Cp9(CpW(BH4)(1+y)_Ly-^ Cp1 and Cp2, identical or different, being chosen from the group consisting of fluorenyl groups, cyclopentadienyl groups and indenyl groups, the groups being substituted or unsubstituted, Pending a group bridging the two groups Cp1 and Cp2, and comprising a silicon or carbon atom, Nd designating the neodymium atom, L represents an alkali metal chosen from the group consisting of lithium, sodium, and potassium, N representing a molecule of an ether, x, an integer or not, being equal to or greater than 0, y, an integer, being equal to or greater than 0, - step b) being the reaction of a compound having a nitrile function with the reaction product of the polymerization of step a), - step c) being a hydrolysis reaction, the polymer being a polyethylene or a copolymer of ethylene and a 1,3-diene and possibly a vinylaromatic compound.

[0007] A second object of the invention is a polymer containing more than 50% by mole of ethylene units and bearing at one of its chain ends a ketone function and optionally a second function which is borne on the same chain end as the ketone function and which is selected from the ether, thioether, amine, al-coxysilane, silanol and imidazole functions, which polymer is a copolymer of ethylene and a 1,3-diene or a copolymer of ethylene, a 1,3-diene and a vinylaromatic compound and is capable of being obtained by particular embodiments of the process according to the invention.

[0008] A third object of the invention is a polyethylene carrying at one of its chain ends a ketone function and a second function which is carried on the same chain end as the ketone function and which is chosen from the ether, thioether, amine, alkoxysilane, silanol and imidazole functions, which polyethylene is capable of being obtained by particular embodiments of the process according to the invention. Detailed description

[0009] 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., bounds a and b excluded) 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 bounds a and b).

[0010] Unless otherwise indicated, the rates of units resulting from the insertion of a monomer into a polymer are expressed as a molar percentage relative to the total units resulting from the polymerization of the monomers.

[0011] The compounds mentioned in the description may be of fossil origin or bio-based. 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 used, 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.

[0012] The expression "based on" used to define the constituents of the catalytic system means the mixture of these constituents, or the product of the reaction of some or all of these constituents with each other.

[0013] Step a) of the process according to the invention is a polymerization reaction of a monomer mixture containing ethylene which allows the preparation of polymer chains, growing chains intended to react in the next step, step b), with a functionalizing agent, a compound having a nitrile function.

[0014] According to a first alternative, the monomer mixture containing ethylene is Ethylene, that is, a monomeric mixture consisting solely of ethylene. According to this alternative, the reaction product of the polymerization in step a) is a polymer chain whose constituent units result from the insertion of ethylene. The polymer prepared by this alternative is a homopolymer of ethylene, polyethylene.

[0015] According to a second alternative, the monomer mixture containing ethylene is a mixture of ethylene and a 1,3-diene. According to this alternative, the reaction product of the polymerization in step a) is a polymer chain whose constituent units result from the insertion of ethylene and 1,3-diene. The polymer prepared by this second alternative is a copolymer of ethylene and a 1,3-diene.

[0016] According to a third alternative of the invention, the monomer mixture containing ethylene is a mixture of ethylene, a 1,3-diene, and a vinylaromatic compound. According to this alternative, the reaction product of the polymerization in step a) is a polymer chain whose constituent units result from the insertion of ethylene, 1,3-diene, and the vinylaromatic compound. The polymer prepared by this third alternative is a copolymer of ethylene, a 1,3-diene, and a vinylaromatic compound.

[0017] The 1,3-diene of the monomer mixture in step a) useful for the needs of the second and third alternatives is a single compound, that is, a single 1,3-diene, or a mixture of 1,3-dienes that differ from one another in chemical structure. Suitable 1,3-dienes are those having from 4 to 20 carbon atoms, such as 1,3-butadiene, isoprene, myrcene, 3-farnesene, and mixtures thereof. The 1,3-diene is preferably 1,3-butadiene, isoprene, myrcene, 3-famesene, or mixtures thereof, in particular a mixture of at least two of them.

[0018] The vinylaromatic compound of the monomer mixture in step a) useful for the needs of the third alternative is a single compound, that is to say, a single vinylaromatic compound or a mixture of vinylaromatic compounds that differ from one another in their chemical structure. A vinylaromatic compound is understood to be an aromatic compound substituted with a vinyl functional group of the well-known formula (-CH=CH2). Compounds having an aryl group substituted with a vinyl functional group, and more particularly compounds having a phenyl group substituted with a vinyl functional group, are particularly suitable as vinylaromatic compounds. The vinylaromatic compound is preferably styrene or a styrene whose benzene ring is substituted with alkyl groups. The vinylaromatic compound is more preferably styrene.The copolymer prepared by a preferred embodiment of the third alternative is a copolymer of ethylene, a 1,3-diene and styrene.

[0019] Preferably, the monomer mixture of step a) contains more than 50 mole percent of ethylene, the percentage being expressed relative to the total number of moles of monomers in the monomer mixture of step a). When the monomer mixture contains a vinylaromatic compound, such as styrene, it preferably contains less than 40 mole percent of the vinylaromatic compound, the percentage being expressed relative to the total number of moles of monomers in the monomer mixture of step a).

[0020] The polymerization of the monomer mixture can be carried out in accordance with patent applications WO 2007054223 A2 and WO 2007054224 A2 using a catalytic system (or catalytic composition) composed of a metallocene and an organomagnesium compound.

[0021] In the present application, the term metallocene means an organometallic complex in which the metal, in this case the neodymium atom, is linked to a molecule called a ligand and consisting of two groups Cp1 and Cp2 linked together by a P-bridge. These groups Cp1 and Cp2, 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] According to the invention, the metallocene used as a basic constituent in the catalytic system corresponds to the formula (la) {P(Cp1)(Cp2)Nd(BH4)(1+y)_Ly-Nx} (I) Pending a group bridging the two groups Cp1 and Cp2, and comprising a silicon or carbon atom, Cp1 and Cp2, identical or different, being chosen from the group consisting of fluorenyl groups, cyclopentadienyl groups and indenyl groups, the groups being substituted or unsubstituted, Nd designating the neodymium atom, L represents an alkali metal chosen from the group consisting of lithium, sodium, and potassium, N representing a molecule of an ether, x, an integer or not, being equal to or greater than 0, y, an integer, being equal to or greater than 0.

[0023] In formula (I), the neodymium atom is bonded to a ligand molecule consisting of two groups Cp1 and Cp2 linked by a bridge P. Preferably, the symbol P, designated as the bridge, has the formula ZR'R2, where Z represents a silicon or carbon atom, and R1 and R2, which may be identical or different, represent an alkyl group comprising from 1 to 20 carbon atoms. More preferably, the bridge P has the formula SiR'R2, where R1 and R2 are identical and as defined above. Even more preferably, P has the formula SiMe2.

[0024] In formula (I), any ether that has the power to complex is suitable as an ether the alkali metal, in particular diethyl ether, methyltetrahydrofuran and tetrahydrofuran, preferably tetrahydrofuran.

[0025] Examples of substituted cyclopentadienyl, fluorenyl, and indenyl groups include those substituted with alkyl groups having 1 to 6 carbon atoms, aryl groups having 6 to 12 carbon atoms, or trialkylsilyl groups such as SiMe3. When the Cp1 and Cp2 ligands are substituted, they are preferentially substituted with methyl groups, butyl groups (particularly tert-butyl groups), or trimethylsilyl groups. The choice of groups is also guided by the availability of the corresponding molecules, namely the substituted cyclopentadienes, fluorenyls, and indenes, because these are either commercially available or easily synthesized.

[0026] Examples of substituted fluorenyl groups include those substituted at positions 2, 7, 3, or 6, particularly 2,7-ditertiobutyl-fluorenyl and 3,6-ditertiobutyl-fluorenyl. Positions 2, 3, 6, and 7 respectively designate the positions of the carbon atoms in the rings, as shown in the diagram below, with position 9 corresponding to the carbon atom to which the P-bridge is attached. P

[0027] Examples of substituted cyclopentadienyl groups include those substituted at position 2 (or 5) as well as at position 3 (or 4), particularly those substituted at position 2, more specifically the tetramethylcyclopentadienyl group. Position 2 (or 5) refers to the position of the carbon atom adjacent to the carbon atom to which the P-bridge is attached, as shown in the diagram below. It should be noted that a substitution at position 2 or 5 is also referred to as an alpha-bridge substitution. P;

[0028] As examples of substituted indenyl groups, particular mention may be made of those substituted at position 2, more specifically 2-methylindenyl and 2-phenylindenyl. Position 2 designates the position of the carbon atom that is adjacent to the carbon atom to which the P-bridge is attached, as shown in the diagram below. After.

[0029] Preferably, Cp1 and Cp2, whether identical or different, are alpha-substituted cyclopentadienyls, substituted fluorenyls, substituted indenyls, or fluorenyls of formula Ci3H8 or indenyls of formula C9H6. More preferably, Cp1 and Cp2, whether identical or different, are substituted fluorenyl groups or unsubstituted fluorenyl groups of formula CnH8. Advantageously, Cp1 and Cp2 are unsubstituted fluorenyl groups of formula CnH8, represented by the symbol Flu.

[0030] Better, the metallocene has the formula (I-1 ), (1-2), (1-3), (1-4) or (1-5): [Me2Si(Flu)2Nd(p-BH4)2Li(THF)] (I-1) [{Me2SiFlu2Nd(p-BH4)2Li(THF)}2] (1-2) [Me2SiFlu2Nd(p-BH4)(THF)] (1-3) [{Me2SiFlu2Nd(p-BH4)(THF)}2] (1-4) [Me2SiFlu2Nd(p-BH4)] (1-5) in which Flu represents the Ci3H8 group.

[0031] The metallocene useful for the synthesis of the catalytic system may be in the form of a crystalline or non-crystalline powder, or in the form of single crystals. The metallocene may be in monomeric or dimeric form, these forms depending on the method of preparation of the metallocene, as described, for example, in patent application WO 2007054224 A2 or WO 2007054223 A2. The metallocene may be prepared in a traditional manner by a process analogous to that described in patent application WO 2007054224 A2 or WO 2007054223 A2, in particular by reacting, under inert and anhydrous conditions, the salt of an alkali metal of the ligand with a rare-earth borohydride, neodymium, in a suitable solvent, such as an ether, like diethyl ether or tetrahydrofuran, or any other solvent known to those skilled in the art.After the reaction, the metallocene is separated from the reaction by-products using techniques known to those skilled in the art, such as filtration or precipitation in a second solvent. The metallocene is then dried and isolated in solid form.

[0032] The organomagnesium compound, another basic constituent of the catalytic system, is the cocatalyst of the catalytic system. Typically, the organomagnesium compound can be a diorganomagnesium compound or a halide of an organomagnesium compound. The organomagnesium compound can have the formula (Ia), (Ilb), (Ile), or (Ild), in which R3, R4, R5, and RB are identical or different, represent a carbon group, RA represents a divalent carbon group, X is a halogen atom, m is a number greater than or equal to 1, preferably equal to 1. MgR3R4 (lia) XMgR5 (Ilb) RB-(Mg-RA)m-Mg-RB (Ile) X-Mg-RA-Mg-X (Ild).

[0033] RA can be an aliphatic hydrocarbon divalent chain, interrupted or not by one or more oxygen or sulfur atoms or by one or more arylene groups.

[0034] A carbon group is defined as a group containing one or more carbon atoms. The carbon group may be a hydrocarbon group (hydrocarbyl group) or a heterohydrocarbon group, that is, a group comprising, in addition to carbon and hydrogen atoms, one or more heteroatoms. Organomagnesium compounds with a heterohydrocarbon group are suitable for the compounds described as transfer agents in patent application WO2016092227 A1. The carbon groups represented by the symbols R3, R4, R5, RB, and RA are preferably hydrocarbon groups.

[0035] Preferably, RA contains 3 to 10 carbon atoms, in particular 3 to 8 carbon atoms.

[0036] Preferably, RA is a divalent hydrocarbon chain. Preferably, RA is a branched or linear alkanediyl, a cycloalkanediyl, or a xylenediyl radical. More preferably, RA is an alkanediyl. Even more preferably, RA is an alkanediyl having 3 to 10 carbon atoms. Advantageously, RA is an alkanediyl having 3 to 8 carbon atoms. Most advantageously, RA is a linear alkanediyl. 1,3-propanediyl, 1,4-butanediyl, 1,5-pentanediyl, 1,6-hexanediyl, 1,7-heptanediyl, and 1,8-octanediyl are particularly suitable RA groups.

[0037] The carbon groups represented by R3, R4, R5, RB, can be aliphatic or aromatic. They can contain one or more heteroatoms such as an oxygen, nitrogen, silicon, or sulfur atom. Preferably, they are alkyl, phenyl, or aryl. They can contain from 1 to 20 carbon atoms.

[0038] The alkyls represented R3, R4, R5, RB can contain 2 to 10 carbon atoms and include ethyl, butyl, octyl.

[0039] The aryls represented R3, R4, R5, RB can contain 7 to 20 carbon atoms and are in particular a phenyl substituted by one or more alkyls such as methyl, ethyl, isopropyl.

[0040] According to a particular embodiment of the invention, R3 comprises a core In this particular embodiment, R4 is a benzene ring substituted with magnesium. One of the carbon atoms of the benzene ring ortho to magnesium is substituted by a methyl, ethyl, or isopropyl group, or forms a ring with its nearest neighbor carbon atom meta to magnesium. The other carbon atom of the benzene ring ortho to magnesium is substituted by a methyl, ethyl, or isopropyl group, and R4 is an alkyl group. In other words, the aforementioned methyl, ethyl, and isopropyl substituents of the benzene ring are ortho to the magnesium atom. R3 can be 1,3-dimethylphenyl, 1,3-diethylphenyl, mesityl, or 1,3,5-triethylphenyl, and R4 can be ethyl, butyl, or octyl.

[0041] According to another particular embodiment of the invention, R3 and R4 are alkyls containing 2 to 10 carbon atoms, in particular ethyl, butyl, octyl.

[0042] R5 is preferably an alkyl containing 2 to 10 carbon atoms, more preferably an ethyl, a propyl, a butyl, a pentyl, a hexyl, a heptyl or an octyl.

[0043] RB may comprise a benzene ring substituted by a magnesium atom, one of the carbon atoms of the benzene ring ortho to magnesium being substituted by a methyl, ethyl, or isopropyl group, or forming a ring with its nearest neighbor carbon atom meta to magnesium, the other carbon atom of the benzene ring ortho to magnesium being substituted by a methyl, ethyl, or isopropyl group. RB may be 1,3-dimethylphenyl, 1,3-diethylphenyl, mesityl, or 1,3,5-triethylphenyl.

[0044] For example, suitable organomagnesium compounds include butylethylmagnesium, butyl-loctylmagnesium, ethylmagnesium chloride, butylmagnesium chloride, pentylmagnesium chloride, ethylmagnesium bromide, butylmagnesium bromide, pentylmagnesium bromide, octylmagnesium chloride, octylmagnesium bromide, 2,6-dimethylphenylbutylmagnesium, 2,6-diethylphenylethylmagnesium, butyl-2-mesitylmagnesium, ethyl-2-mesitylmagnesium, 2,6-diethylphenylbutylmagnesium, 2,6-diethylphenylethylmagnesium, 2,6-diisopropylphenylbutylmagnesium, 2,6-disopropylphenylethylmagnesium, 2,4,6-triethylphenylbutylmagnesium, 2,4,6-triethylphenylethylmagnesium, 2,4,6-triisopropylphenylbutylmagnesium, 2,4,6-triisopropylphenylethylmagnesium, l,3-di(magnesium bromide)-propanediyl, l,3-di(magnesium chloride)-propanediyl, l,5-di(magnesium bromide)-pentanediyl, l,5-di(magnesium chloride)-pentanediyl, l,8-Di(magnesium bromide)-octanediyl, the 1,8-di(magnesium chloride)-octanediyl.

[0045] The organomagnesium compound of formula (Ile) can be prepared by a process, which This involves the reaction of a first organomagnesium compound with the formula X'Mg-RA-MgX' with a second organomagnesium compound with the formula RB-Mg-X', where X' represents a halogen atom, preferably bromine or chlorine, and RB and RA are as defined previously. X' is more preferably a bromine atom. The stoichiometry used in the reaction determines the value of m in the formula (Ile). For example, a molar ratio of 0.5 between the amount of the first organomagnesium compound and the amount of the second organomagnesium compound favors the formation of an organomagnesium compound with the formula (Ile) in which m is equal to 1, whereas a molar ratio greater than 0.5 will be more favorable to the formation of an organomagnesium compound with the formula (Ile) in which m is greater than 1.

[0046] To carry out the reaction of the first organomagnesium compound with the second organomagnesium compound, a solution of the second organomagnesium compound is typically added to a solution of the first organomagnesium compound. The solutions of the first and second organomagnesium compounds are generally solutions in an ether, such as diethyl ether, dibutyl ether, tetrahydrofuran, methyltetrahydrofuran, or a mixture of two or more of these ethers. A hydrocarbon, aliphatic, or aromatic solvent may be added to the ether as a co-solvent. Preferably, the respective concentrations of the solutions of the first and second organomagnesium compounds are 0.01 to 3 mol / L and 0.02 to 5 mol / L, respectively. More preferably, the respective concentrations of the first organomagnesium and the second organomagnesium are respectively 0.1 to 2 mol / L and 0.2 to 4 mol / L.

[0047] The first organomagnesium reagent and the second organomagnesium reagent, Grignard reagents, can be prepared beforehand from magnesium metal and a suitable halogenated precursor in a reactor. For the first and second organomagnesium reagents, the respective precursors have the formulas X'-RA-X' and RB-X', RA, RB, and X' being as defined previously. The preparation of the Grignard reagents is typically carried out by adding the precursor to magnesium metal, which is generally in the form of chips. Preferably, iodine (I2), typically in the form of beads, is introduced into the reactor before the addition of the precursor in order to activate the Grignard reaction in a known manner.

[0048] Alternatively, the organomagnesium compound of formula (Ile) can be prepared by reacting an organometallic compound of formula M-RA-M and the organomagnesium compound of formula RB-Mg-X', where M represents a lithium, sodium, or potassium atom, and X', RB, and RA are as defined previously. Preferably, M represents a lithium atom, in which case the organometallic compound of formula M-RA-M is an organolithium compound.

[0049] The reaction of the organolithium and organomagnesium compounds is typically carried out in an ether such as diethyl ether, dibutyl ether, tetrahydrofuran, methyl te- trahydrofuran, methylcyclohexane, toluene, or a mixture thereof. The reaction is also typically carried out at a temperature ranging from 0°C to 60°C. Contacting is preferably performed at a temperature between 0°C and 23°C. Contacting the organometallic compound of formula M-RA-M with the organomagnesium compound of formula RB-Mg-X' is preferably achieved by adding a solution of the organometallic compound M-RA-M to a solution of the organomagnesium compound RB-Mg-X'. The solution of the organometallic compound M-RA-M is generally a solution in a hydrocarbon solvent, preferably n-hexane, cyclohexane, or methylcyclohexane; the solution of the organomagnesium compound RB-Mg-X' is generally a solution in an ether, preferably diethyl ether or dibutyl ether. Preferably, the respective concentrations of the solutions of the organometallic compound and of the organomagnesium compound M-RA-M and RB-Mg-X' are respectively 0.01 to 1 mol / L and 0.02 to 5 mol / L.More preferably, the respective concentrations of the solutions of the organometallic compound and the organomagnesium compound M-RA-M and RB-Mg-X' are respectively 0.05 to 0.5 mol / L and 0.2 to 3 mol / L.

[0050] As with any synthesis carried out in the presence of organometallic compounds, the syntheses described for the synthesis of organomagnesium compounds take place under anhydrous conditions in an inert atmosphere, in stirred reactors. Typically, solvents and solutions are used under anhydrous nitrogen or argon.

[0051] Once the organomagnesium compound of formula (Ile) is formed, it is generally recovered in solution after filtration conducted under an inert and anhydrous atmosphere. It can be stored in solution in airtight containers, for example capped bottles, at a temperature between -25°C and 23°C before use.

[0052] Compounds of formula (Ild), which are Grignard reagents, are described, for example, in J. Mardi's "Advanced Organic Chemistry," 4th Edition, 1992, pages 622-623, or in the "Handbook of Grignard Reagents," edited by Gary S. Silverman and Philip E. Rakita, 1996, pages 502-503. They can be synthesized by contacting magnesium metal with a dihalogenated compound of formula X-RA-X, where RA is as defined according to the invention. For their synthesis, reference may be made, for example, to the "Organic Synthesis" series of volumes.

[0053] The compounds of formula (lia) and (Ilb), which are also Grignard reagents, are well known; some of them are even commercial products. For their synthesis, one can, for example, refer to the collection of volumes of "Organic Synthesis".

[0054] Like all organomagnesium compounds, the organomagnesium compound constituting the catalytic system, in particular with the formula (Ha), (Ilb), (Ile) or (Ild), can be in the form of a monomeric entity or in the form of a polymer entity. By way of illustration, the organomagnesium compound (Ile) can be in the form of an entity monomer (RB-(Mg-RA)m-Mg-RB)i or as a polymer entity (RB-(Mg-RA)m-Mg-RB)p, where p is an integer greater than 1, in particular dimer (RB-(Mg-RA)m-Mg-RB)2, where m is as defined previously. Similarly, also by way of illustration, the organomagnesium compound with formula (Ild) can be in the form of a monomer entity (X-Mg-RA-Mg-X)i or as a polymer entity (X-Mg-RA-Mg-X)p, where p is an integer greater than 1, in particular dimer (X-Mg-RA-Mg-X)2.

[0055] Furthermore, whether in the form of a monomeric or polymeric entity, the organomagnesium can also be in the form of an entity coordinated by one or more molecules of a solvent, preferably an ether such as diethyl ether, tetrahydrofuran or methyltetrahydrofuran.

[0056] In formulas (Ilb) and (Ild), X is preferably a bromine or chlorine atom.

[0057] According to a highly preferred embodiment of the invention, the organomagnesium compound is an organomagnesium halide, preferably of formula (Ilb) or (Ild), more preferably of formula (Ilb), and even more preferably of formula (Ilb) XMgR5, in which X is a chlorine or bromine atom, R5 is an alkyl or aryl group, preferably an alkyl group. According to this highly preferred embodiment, R5 is advantageously an alkyl group containing 2 to 10 carbon atoms, more preferably an ethyl, propyl, butyl, pentyl, hexyl, heptyl, or octyl group. When the organomagnesium is a halide of an organomagnesium of formula (Ilb) or (Ild), preferably of formula (Ilb), the process according to the invention leads to yields of polymer bearing a ketone function at one of its chain ends which are among the highest, compared to the yields obtained using a diorganomagnesium.

[0058] The quantities of co-catalyst and metallocene reacted are such that the ratio between the number of moles of Mg in the co-catalyst and the number of moles of the rare earth element in the metallocene, neodymium, preferably ranges from 0.5 to 200, more preferably from 1 to less than 20. These preferred ranges can be applied to any of the embodiments of the invention. The range of values ​​from 1 to less than 20 is particularly favorable for obtaining copolymers with high molar masses.

[0059] According to one embodiment, the catalytic system can be prepared conventionally by a process analogous to that described in patent applications WO 2007054224 A2 or WO 2007054223 A2. For example, the co-catalyst, in this case the organomagnesium compound, and the metallocene are typically reacted in a hydrocarbon solvent at a temperature ranging from 20 to 80°C for a duration of between 5 and 60 minutes. The catalytic system is generally prepared in a hydrocarbon solvent, aliphatic such as methylcyclohexane or aromatic such as toluene. Generally after its synthesis, the catalytic system is used as is for step a).

[0060] According to another embodiment, the catalytic system can be prepared by a process analogous to that described in patent application WO 2017093654 A1 or in patent application WO 2018020122 A1: it is said to be of the preformed type. For example, the organomagnesium compound and the metallocene are typically reacted in a hydrocarbon solvent at a temperature of 20 to 80°C for 10 to 20 minutes to obtain a first reaction product, then a preformed monomer is reacted with this first reaction product at a temperature ranging from 40 to 90°C for 1 to 12 hours. The preforming monomer is preferably used with a molar ratio (preforming monomer / metal of the metallocene) of 5 to 1000, preferably 10 to 500. Before its use in polymerization, the preformed type catalytic system can be stored under an inert atmosphere, in particular at a temperature ranging from -20°C to room temperature (23°C).According to this second embodiment, the preformed catalytic system has as its basic constituent a preforming monomer chosen from among 1,3-dienes, ethylene, and mixtures thereof. In other words, the so-called preformed catalytic system contains, in addition to the metallocene and the cocatalyst, a preforming monomer. The 1,3-diene used as the preforming monomer can be 1,3-butadiene, isoprene, or a 1,3-diene with the formula CH2=CR6-CH=CH2, the symbol R6 representing a hydrocarbon group having 3 to 20 carbon atoms, in particular myrcene or 3-farnesene. The preforming monomer is preferably 1,3-butadiene.

[0061] The catalytic system is typically present in a solvent which is preferably the solvent in which it was prepared, and the concentration of rare earth metal, i.e. neodymium, of metallocene is then in a range preferably from 0.0001 to 0.2 mol / L more preferably from 0.001 to 0.03 mol / L.

[0062] As with any synthesis carried out in the presence of an organometallic compound, the synthesis of the metallocene, the synthesis of the organomagnesium compound, and the synthesis of the catalytic system take place under anhydrous conditions in an inert atmosphere. Typically, the reactions are conducted using solvents and anhydrous compounds in the presence of nitrogen or anhydrous argon.

[0063] The polymerization of the monomer mixture is preferably carried out in solution, either continuously or batchwise. The polymerization solvent is typically a hydrocarbon, aromatic, or aliphatic solvent, such as toluene, cyclohexane, methylcyclohexane, or a mixture of two or all three. The monomer mixture can be introduced into the reactor containing the polymerization solvent. The polymerization system and the catalytic system, or conversely the catalytic system, can be introduced into the reactor containing the polymerization solvent and the monomer mixture. The monomer mixture and the catalytic system can be introduced simultaneously into the reactor containing the polymerization solvent, particularly in the case of continuous polymerization. Polymerization is typically carried out under anhydrous conditions and in the absence of oxygen, possibly in the presence of an inert gas. The polymerization temperature generally varies within a range of 40 to 150°C, preferably 40 to 120°C. Those skilled in the art adapt the polymerization conditions, such as the polymerization temperature, the concentration of each reactant, and the pressure in the reactor, according to the composition of the monomer mixture, the polymerization reactor, and the desired microstructure and macrostructure of the copolymer chain.

[0064] Polymerization is preferably carried out at constant pressure in monomers. A continuous addition of each or one of the monomers can be made to the polymerization reactor, in which case the polymerization reactor is a fed reactor. This embodiment is particularly suitable for the statistical incorporation of monomers. Preferably, the polymerization in step a) is a statistical polymerization, resulting in the statistical incorporation of monomers from the monomer mixture used in step a).

[0065] Once the desired monomer conversion rate is achieved in the polymerization reaction of step a), step b) is carried out, which is a functionalization reaction.

[0066] Step b) of the process according to the invention brings together a functionalizing agent, a compound having a nitrile function, with the reaction product of step a).

[0067] Preferably, step b) is also carried out in a hydrocarbon solvent. Advantageously, it is carried out in the reaction medium obtained from step a). It is generally implemented by adding the compound having a nitrile functional group to the reaction product of step a) in its reaction medium under stirring.

[0068] Before adding the nitrile compound, the reactor is preferably degassed and inerted. Degassing the reactor eliminates residual gaseous monomers and also facilitates the addition of the nitrile compound. Inerting the reactor, for example with nitrogen, prevents the carbon-metal bonds present in the reaction medium and necessary for the polymer functionalization reaction from being deactivated. The nitrile compound can be added pure or diluted in a hydrocarbon, aliphatic, or aromatic solvent. The nitrile compound is left in contact with the reaction product of step a), preferably under stirring, for the time required for the functionalization reaction. of the polymer chain end. The functionalization reaction can typically be monitored by chromatographic analysis to track the consumption of the compound with a nitrile function. The functionalization reaction is preferably carried out at a temperature ranging from 23 to 120°C, preferably from 40°C to 100°C.

[0069] The functionalization reaction, step b), is preferably carried out with at least one mole equivalent of nitrile function relative to the number of carbon-magnesium bonds per mole of organomagnesium compound. The ratio between the number of mole equivalents of nitrile function and the number of carbon-magnesium bonds per mole of organomagnesium compound can vary widely as long as it is at least 1, i.e., at least one mole equivalent of nitrile function is used relative to the number of carbon-magnesium bonds per mole of organomagnesium compound.An excess of a compound with a nitrile functional group can be used, but it is preferable to use no more than 3 molar equivalents of nitrile functional group relative to the number of carbon-magnesium bonds, particularly for cost reasons. For example, in a halide of an organomagnesium compound with formula (Ilb) such as n-butylmagnesium chloride, there is one carbon-magnesium bond per mole of halide; in magnesium compounds with formula (Lia) such as butylmagnesium (BOMAG) or in magnesium compounds with formula (Ild) there are two carbon-magnesium bonds per mole of magnesium compound. One mole of a compound with a single nitrile functional group is equivalent to one molar equivalent of nitrile functional group; one mole of a compound with two nitrile functional groups is equivalent to two molar equivalents of nitrile functional group. More generally, one mole of a compound having n nitrile functions is equivalent to n molar equivalents of nitrile function, n being an integer greater than or equal to 1.

[0070] The compound having a nitrile functional group may be an aliphatic compound or an aromatic compound, preferably aromatic, and preferably contains a single nitrile functional group. The compound having a nitrile functional group is typically a compound having a hydrocarbon chain substituted by a single nitrile functional group or by several nitrile functional groups, preferably a single nitrile functional group. The hydrocarbon chain of the compound having a nitrile functional group may also be substituted by another functional group containing one or more heteroatoms selected from oxygen, sulfur, nitrogen, and silicon atoms. The hydrocarbon chain of the compound having a nitrile functional group may be linear, cyclic, or branched.

[0071] Preferably, the compound having a nitrile function contains a second function which is chosen from the ether, thioether, protected amine, tertiary amine, al-coxysilane and imidazole functions, which is preferably an ether function, a tertiary amine function, an alkoxysilane function or an imidazole function.

[0072] According to a first embodiment of the invention, the compound having a nitrile function is an alkane substituted by a nitrile function, preferably a single function Nitrile. The length of the hydrocarbon chain of an alkane substituted with a nitrile group is not limited per se, and the number of carbon atoms in the hydrocarbon chain can vary widely, for example, from 1 to 11 carbon atoms. The choice of a nitrile-substituted alkane may be motivated by its commercial availability or its ease of synthesis. Particularly suitable are rethanenitrile or acetonitrile, propanenitrile or propionitrile, butanenitrile or butyronitrile, pentanenitrile or valeronitrile, hexanenitrile or capronitrile, and dodecanenitrile or laurylnitrile.

[0073] According to a second embodiment of the invention, the compound having a nitrile functional group is an alkane substituted by a nitrile functional group and also by another functional group containing one or more heteroatoms selected from oxygen, sulfur, nitrogen, and silicon atoms, and which is different from a nitrile functional group. According to this embodiment, the compound having a nitrile functional group preferably contains a single nitrile functional group. The other functional group is preferably selected from ether, thioether, protected amine, tertiary amine, and alkoxysilane functional groups, and more preferably is a tertiary amine or an alkoxysilane functional group.Particularly suitable are dialkylaminoalkanenitriles, alkyloxyalkanenitriles, trialcoxysilylalkanenitriles, alkyldialkoxysilylalkanenitrile, and dialkylalkoxysilylalkanenitrile, in which the alkyl and alkoxy chains preferentially contain 1 to 2 carbon atoms and the alkane chains preferentially contain 2 to 6 carbon atoms, more preferably 2 to 3 carbon atoms. The choice of the substituted alkane may be motivated by its commercial availability or its ease of synthesis.Examples include dimethylaminopropionitrile, dimethylaminobutyronitrile, diethylaminopropionitrile, diethylaminobutyronitrile, methoxypropionitrile, methoxybutyronitrile, rethoxypropionitrile, ethoxybutyronitrile, triethoxysilylpropionitrile, triethoxy-silylbutyronitrile, trimethoxysilylpropionitrile, trimethoxysilylbutyronitrile, methyldimethoxysilylpropionitrile, methyldimethoxysilylbutyronitrile, methyldiethoxysilylpropionitrile, methyldimethoxysilylbutyronitrile, and ethyldimethoxysilylpropionitrile. ethyldimethoxysilylbutyronitrile, ethyldiethoxysilylpropionitrile, ethyldiethoxysilylbutyronitrile, dimethylmethoxysilylpropionitrile, dimethylmethoxysilylbutyronitrile, dimethylethoxysilylpropionitrile, dimethylmethoxysilylbutyronitrile, diethylmethoxysilylpropionitrile, diethylethoxysilylpropionitrile, diethylethoxysilylbutyronitrile. .

[0074] According to a third, particularly preferred embodiment, the compound having a nitrile function is an arene substituted with a nitrile function, preferably a single nitrile function. The arene may also bear one or more other substituents constituents other than a nitrile functional group. The arene may be substituted by a hydrocarbon chain or functional group other than a nitrile functional group that contains one or more heteroatoms such as oxygen, sulfur, nitrogen, and silicon atoms. The functional group is preferentially chosen from ether, thioether, protected amine, tertiary amine, and imidazole functional groups. The arene may also be substituted by a hydrocarbon chain that is itself substituted by a functional group chosen from ether, thioether, protected amine, tertiary amine, and imidazole functional groups. The hydrocarbon chains in the compound having a nitrile functional group are preferentially alkyl groups. The alkyl groups in the compound having a nitrile functional group preferentially contain 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms.

[0075] The compound having a nitrile function is more preferably a benzonitrile, benzonitrile, or a substituted benzonitrile, preferably substituted with a function selected from ether, thioether, protected amine, tertiary amine, and imidazole functions. The benzonitrile useful for the purposes of the invention is typically of formula (III) in which the symbols Xi to X5, identical or different, each represent a hydrogen atom, an alkyl group, or a function selected from ether, thioether, protected amine, tertiary amine, and imidazole functions, preferably an ether, a tertiary amine, or an imidazole function.Advantageously, four of the symbols Xi to X5 in formula (III) represent a hydrogen atom or an alkyl group, preferably a hydrogen atom, and the fifth symbol represents an ether, a thioether, a protected amine, a tertiary amine, or an imidazole group, preferably an ether, a tertiary amine, or an imidazole group. The alkyl group of the benzonitrile compound preferably contains 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms.Particularly suitable are the following substituted benzonitriles and benzonitriles, whether substituted in para, meta or ortho, preferably in para or ortho, such as alkoxybenzonitriles like methoxybenzonitrile, ethoxybenzonitrile, thioalkoxybenzonitriles like thiomethoxybenzonitrile, thioethoxybenzonitrile, N,N-dialkylaminobenzonitriles like N,N-dimethylaminobenzonitrile, N,N-diethylaminobenzonitrile, imidazolylbenzonitriles like 2-(1H-imidazol-1-yl)benzonitrile, 4-(1H-imidazol-1-ylmethyl)benzonitrile.

[0076] Once the chain end has been modified, step b) is followed by step c). Step c) is typically a hydrolysis reaction that forms the ketone function in the polymer chain and, if necessary, deactivates any remaining reactive sites in the reaction medium. The hydrolysis reaction is generally carried out by adding water to the reaction medium or vice versa, possibly in the presence of an acid. Typically, the reaction medium resulting from step b) is treated with an aqueous hydrochloric acid solution. The hydrolysis reaction can be carried out at a temperature ranging from 0°C to 100°C, preferably at room temperature (23°C) or at the reaction temperature of step b), or at a temperature within the range of room temperature to the reaction temperature of step b).In the case where the polymer also contains a protected amine function or an alkoxysilane function, step c) may be followed or accompanied by a hydrolysis reaction of the protected amine function to an amine function or of the alkoxysilane function to a silanol function, as described for example in patent application EP 2 266 819 AL.

[0077] Following step c), the polymer can be separated from the reaction medium by methods well known to those skilled in the art, for example by evaporation of the solvent under reduced pressure or by steam stripping. According to one embodiment of the invention, step c) and the separation of the polymer from the reaction medium can be carried out in the same operation, for example a steam stripping operation, particularly in the presence of an acid.

[0078] Polymers that can be synthesized by the process according to the invention are characterized by having a ketone functional group at the end of their chain, that is, at one of their chain ends, in particular a ketone functional group whose CO group is directly attached to a monomer unit of the polymer. A ketone functional group whose CO group is directly attached to a monomer unit of the polymer is understood to be a ketone functional group in which the carbon atom of the CO group of the ketone functional group is involved in a covalent bond with a carbon atom of a monomer unit of the polymer. Preferably, the polymers bear a second functional group located at the same chain end as the ketone functional group, which is selected from among ether, thioether, amine, alkoxysilane, silanol, and imidazole functional groups. The second functional group is preferably an amine, preferably a tertiary amine, an alkoxysilane, a silanol, or an imidazole, more preferably a tertiary amine, a silanol, or an imidazole. The alkoxysilane functional group advantageously has the formula Si(OR)3 nRn, where R, the same or different, is a methyl or ethyl group, and n is an integer from 0 to 3.

[0079] According to a first embodiment, the polymer carries a ketone function at only one of its chain ends. This embodiment can be implemented by the synthesis process according to the invention in which the organomagnesium compound has the formula (lia) and (Ilb).

[0080] According to a second embodiment, the polymer carries a ketone function at each of its chain ends. This embodiment can be implemented by the synthesis process according to the invention in which the organomagnesium compound has the formula (Ile) and (Ild).

[0081] According to a first embodiment applicable to the first and second variants, the ketone function is a substituent of an aliphatic hydrocarbon chain. The hydrocarbon chain may be linear, cyclic, or branched. The hydrocarbon chain is preferably an alkyl having 1 to 11 carbon atoms. Ethyl, propyl, pentyl, and lauryl hydrocarbon chains are particularly suitable. The polymers defined according to this first embodiment can be prepared by implementing the first embodiment of the process according to the invention.

[0082] According to a second embodiment applicable to both the first and second variants, the ketone functional group is a substituent on an aliphatic hydrocarbon chain that is also substituted by another functional group containing one or more heteroatoms selected from oxygen, sulfur, nitrogen, and silicon atoms, and which is different from a ketone functional group. The other functional group is preferably selected from ether, thioether, or amine functional groups, more preferably a tertiary amine, an alkoxysilane, or a silanol functional group, and even more preferably a tertiary amine or a silanol functional group. The polymers defined according to this second embodiment can be prepared by implementing the second embodiment of the process according to the invention.

[0083] According to a third embodiment applicable to the first and second variants, the ketone function is a substituent of an aryl group, preferably a phenyl group. The aryl group may also be substituted by a hydrocarbon chain or a functional group other than a nitrile function, containing one or more heteroatoms such as oxygen, sulfur, nitrogen, and silicon atoms. The functional group is preferably chosen from ether, thioether, amine (preferably a tertiary amine), and imidazole functions. The arene may be substituted by a hydrocarbon chain that is also substituted by a function chosen from ether, thioether, or amine (preferably a tertiary amine). Hydrogen chains Carbon-based compounds substituting for the aryl group, particularly phenyl groups, are preferentially alkyls. These alkyls preferentially contain 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms. The polymers defined according to this third method can be prepared by implementing the third embodiment of the process according to the invention.

[0084] According to a fourth embodiment applicable to the first and second variants, the ketone functional group is a substituent of a phenyl group substituted by an alkyl group or a functional group selected from ether, thioether, amine (preferably a tertiary amine), and imidazole (preferably an ether, a tertiary amine, or an imidazole) functional groups. The alkyl group substituting the phenyl group preferably contains 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms. The polymers defined according to this fourth embodiment can be prepared by implementing the third embodiment of the process according to the invention, in which the compound having a nitrile functional group is a substituted benzonitrile.

[0085] The second object of the invention is a copolymer of ethylene, a 1,3-diene, and optionally a vinylaromatic compound. This copolymer carries a ketone functional group at one of its chain ends and optionally a second functional group located at the same chain end as the ketone group, selected from ether, thioether, amine, alkoxysilane, silanol, and imidazole functional groups. It can be obtained by the process according to the invention in the alternative whereby the monomer mixture to be polymerized containing ethylene is a mixture of ethylene, a 1,3-diene, and optionally a vinylaromatic compound. The two variants described above, which define the polymers that can be obtained by the process according to the invention, as well as the four methods described as applicable to these two variants, can be applied to the copolymer, the second object of the invention.The amine function carried by the copolymer according to the invention is preferably a tertiary amine function.

[0086] The copolymer also has the essential characteristic of containing more than 50% by mole of ethylene units, the percentage being expressed relative to all the units resulting from the polymerization of the monomers of the monomer mixture, in this case ethylene, 1,3-diene and, where applicable, the vinylaromatic compound. The 1,3-diene and the vinylaromatic compound are as defined in any one of the embodiments of the process according to the invention.

[0087] Preferably, the copolymer also contains 1,2-cyclohexane cyclic motifs. The 1,2-cyclohexane cyclic motifs are of formula (IV). H?C---CH2 / \ H,C CH2 CH*”CH

[0088] When the copolymer contains 1,2-cyclohexane cyclic motifs, it is a copolymer according to a particular embodiment of the invention in which the 1,3-diene is 1,3-butadiene or a mixture of 1,3-dienes, one of which is 1,3-butadiene, and in which the cyclic motifs 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))-. It is notably obtained by the process according to the invention in the embodiment in which the metallocene of the catalytic system has as its ligand two fluorenyl groups, substituted or unsubstituted. The mechanism for obtaining such a microstructure is described for example in the document Macromolecules 2009, 42, 3774-3779.When the polymer according to the invention contains 1,2-cyclohexane cyclic motifs, it preferably contains at most 15% by mole, the percentage being expressed in relation to the total number of units resulting from the polymerization of the monomers of the monomer mixture.

[0089] According to any one of the embodiments of the invention, the copolymer according to the invention is preferably statistical.

[0090] The third object of the invention is a polyethylene bearing a ketone functional group at one of its chain ends and a second functional group at the same chain end as the ketone group, selected from ether, thioether, amine, alkoxysilane, silanol, and imidazole functional groups. It can be obtained by the process according to the invention in the alternative whereby the monomer mixture to be polymerized containing ethylene is a monomer mixture consisting solely of ethylene. The two variants described above, which define the polymers that can be obtained by the process according to the invention, and combined with the second or fourth mode described as applicable to these two variants, can be applied to the polyethylene, the third object of the invention. The amine functional group borne by the polyethylene according to the invention is preferably a tertiary amine functional group.

[0091] The polymer according to the invention, whether it be a copolymer or a polyethylene, respectively the second and third objects of the invention, can be used in compositions containing one or more ingredients or constituents other than the polymer according to the invention, for example additives traditionally used in polymer compositions such as antioxidants, plasticizers, pigments, fillers.

[0092] In summary, the invention is advantageously implemented according to any one of the following embodiments 1 to 34:

[0093] Mode 1: A process for preparing a polymer containing more than 50% by mole of ethylene units and having a ketone function at one of its chain ends, which process comprises the successive steps a), b) and c) - step a) being the polymerization of a monomer mixture containing ethylene in the presence of a catalytic system based on at least one metallocene of formula (I) and an organomagnesium {P(Cp9(Cp2)Nd(BH4)(1+y)^ Cp1 and Cp2, identical or different, being chosen from the group consisting of fluorenyl groups, cyclopentadienyl groups and indenyl groups, the groups being substituted or unsubstituted, Pending a group bridging the two groups Cp1 and Cp2, and comprising a silicon or carbon atom, Nd designating the neodymium atom, L represents an alkali metal chosen from the group consisting of lithium, sodium, and potassium, N representing a molecule of an ether, x, whether an integer or not, being equal to or greater than 0, y, an integer, being equal to or greater than 0, - step b) being the reaction of a compound having a nitrile function with the reaction product of the polymerization of step a), - step c) being a hydrolysis reaction, the polymer being a polyethylene or a copolymer of ethylene and a 1,3-diene and possibly a vinylaromatic compound.

[0094] Mode 2: Process according to mode 1 in which the 1,3-diene monomer is 1,3-butadiene, isoprene, myrcene, [3-farnesene or mixtures thereof.

[0095] Mode 3: Process according to mode 1 or 2 in which the monomer mixture is ethylene.

[0096] Mode 4: Process according to mode 1 or 2 in which the monomer mixture is a mixture of ethylene and a 1,3-diene.

[0097] Mode 5: Process according to mode 1 or 2 in which the monomer mixture is a mixture of ethylene, a 1,3-diene and a vinylaromatic compound.

[0098] Mode 6: Process according to mode 5 in which the vinylaromatic compound is styrene.

[0099] Mode 7: A process according to any one of modes 1 to 6 in which the mixture monomer of step a) contains more than 50% by mole of ethylene, the percentage being expressed in relation to the total number of moles of monomers in the monomer mixture of step a).

[0100] Mode 8: A process according to any one of modes 1 to 7 in which Cp1 and Cp2, identical or different, are substituted fluorenyl groups or unsubstituted fluorenyl groups of formula CnH8, preferably unsubstituted fluorenyl groups.

[0101] Mode 9: Process according to any one of modes 1 to 8 in which the metallocene is of formula (1-1), (1-2), (1-3), (1-4) or (1-5): [Me2Si(Flu)2Nd(p-BH4)2Li(THF)] (I-1) [{Me2SiFlu2Nd(p-BH4)2Li(THF)}2] (1-2) [Me2SiFlu2Nd(p-BH4)(THF)] (1-3) [{Me2SiFlu2Nd(p-BH4)(THF)}2] (1-4) [Me2SiFlu2Nd(p-BH4)] (1-5) where Flu represents the Ci3H8 group.

[0102] Mode 10: A process according to any one of modes 1 to 9 in which the organomagnesium compound is of formula (lia), (Ilb), (Ile) or (Ild) in which R3, R4, R5, RB, identical or different, represent a carbon group, RA represents a divalent carbon group, X is a halogen atom, m is a number greater than or equal to 1, preferably equal to 1. MgR3R4 (lia) XMgR5 (Ilb) RB-(Mg-RA)m-Mg-RB (Ile) X-Mg-RA-Mg-X (Bd).

[0103] Mode 11: Process according to mode 10 in which RA is an aliphatic hydrocarbon divalent chain, interrupted or not by one or more oxygen or sulfur atoms or by one or more arylene groups.

[0104] Mode 12: Process according to mode 10 or 11 in which RA is an alkanediyl, branched or linear, a cycloalkanediyl or a xylenediyl radical.

[0105] Mode 13: Process according to any one of modes 10 to 12 in which RA is an alkanediyl having 3 to 8 carbon atoms.

[0106] Mode 14: A method according to any one of modes 10 to 13 in which RB comprises a benzene ring substituted by the magnesium atom, one of the carbon atoms of the benzene ring ortho to the magnesium being substituted by a methyl, an ethyl, an isopropyl or forming a ring with the carbon atom which is its nearest neighbor and which is meta to the magnesium, the other carbon atom of the benzene ring ortho to the magnesium being substituted by a methyl, an ethyl or an isopropyl.

[0107] Mode 15: Process according to mode 14 in which RB is 1,3-dimethylphenyl, 1,3-diethylphenyl, mesityl, or 1,3,5-triethylphenyl.

[0108] Mode 16: A method according to mode 10 in which R3 comprises a benzene ring substituted by the magnesium atom, one of the carbon atoms of the benzene ring ortho to the magnesium being substituted by a methyl, an ethyl, an isopropyl or forming a ring with the carbon atom which is its nearest neighbor and which is meta to the magnesium, the other carbon atom of the benzene ring ortho to the magnesium being substituted by a methyl, an ethyl or an isopropyl and R4 is an alkyl.

[0109] Mode 17: Process according to mode 16 in which R3 is 1,3-dimethylphenyl, 1,3-diethylphenyl, mesityl, or 1,3,5-triethylphenyl and R4 is ethyl, butyl, octyl.

[0110] Mode 18: Process according to mode 10 in which R3 and R4 are alkyls containing 2 to 10 carbon atoms.

[0111] Mode 19: Process according to mode 10 in which R5 is an alkyl containing 2 to 10 carbon atoms.

[0112] Mode 20: A process according to any one of modes 10 to 13 or 19 in which X is a bromine or chlorine atom.

[0113] Mode 21: A process according to any one of modes 10 to 13 or 19 to 20 in which the organomagnesium compound is a halide of an organomagnesium compound, preferably of formula (Ilb) or (Ild) defined in mode 10.

[0114] Mode 22: A process according to any one of modes 10 to 13 or 19 to 21 in which the organomagnesium compound is a halide of an organomagnesium compound of formula XMgR5, X being a chlorine or bromine atom, R5 an alkyl or aryl.

[0115] Mode 23: A process according to any one of modes 10 to 13 or 19 to 22 in which the organomagnesium compound is a halide of an organomagnesium compound of formula XMgR5, X being a chlorine or bromine atom, R5 being an alkyl containing 2 to 10 carbon atoms.

[0116] Mode 24: A process according to any one of modes 10 to 13 or 19 to 23 in which the organomagnesium compound is a halide of an organomagnesium compound of formula XMgR5, X being a chlorine or bromine atom, R5 being an ethyl, propyl, butyl, pentyl, hexyl, heptyl or octyl.

[0117] Mode 25: A process according to any one of modes 1 to 24 in which the compound having a nitrile function contains a single nitrile function.

[0118] Mode 26: A process according to any one of modes 1 to 25 in which the compound having a nitrile function is an alkane substituted by a nitrile function, preferably having 1 to 11 carbon atoms.

[0119] Mode 27: A process according to any one of modes 1 to 25 in which the compound having a nitrile function is an arene substituted by a nitrile function, preferably benzonitrile.

[0120] Mode 28: A process according to any one of modes 1 to 25 in which the compound having a nitrile function is a compound which contains a second function which is selected from the ether, thioether, protected amine, tertiary amine, al-coxysilane and imidazole functions, preferably an ether function, a tertiary amine function, an alkoxysilane function or an imidazole function.

[0121] Mode 29: A process according to any one of modes 1 to 25 in which the compound having a nitrile function is an alkane substituted by a nitrile function and by a function which is selected from the ether, thioether, protected amine, tertiary amine and alkoxysilane functions, preferably a tertiary amine or an alkoxysilane function.

[0122] Mode 30: Process according to any one of modes 1 to 25 in which the compound having a nitrile function is an arene substituted by a nitrile function, preferably a substituted benzonitrile.

[0123] Mode 31: A process according to any one of modes 1 to 25 in which the compound having a nitrile function is a benzonitrile substituted by a function selected from the ether, thioether, protected amine, tertiary amine and imidazole functions, preferably an ether, a tertiary amine or an imidazole function.

[0124] Mode 32: A process according to any one of modes 1 to 31 in which step b) is carried out with at least one molar equivalent of nitrile function relative to the number of carbon-magnesium bonds per mole of organomagnesium.

[0125] Mode 33: Polymer containing more than 50 mole percent of ethylene units and bearing on one of its chain ends a ketone function and optionally a second function which is borne on the same chain end as the ketone function and which is selected from the ether, thioether, amine, alkoxysilane, silanol and imidazole functions, which polymer is a copolymer of ethylene and a 1,3-diene or a copolymer of ethylene, a 1,3-diene and a vinylaromatic compound.

[0126] Mode 34: Polyethylene carrying at one of its chain ends a ketone function and a second function which is carried on the same chain end as the ketone function and which is selected from the ether, thioether, amine, alkoxysilane, silanol and imidazole functions.

[0127] The aforementioned features of the present invention, as well as others, will be better understood upon reading the following description of examples of embodiments of the invention, given by way of illustration and not limitation. Examples

[0128] Characterization of polymers:

[0129] High-temperature size exclusion chromatography (SEC-HT) for characterizing polyethylenes: High-temperature size-exclusion chromatography (HTSEC) analyses were performed using a Viscotek instrument (Malvern Instruments) equipped with three columns (PLgel Olexis 300 mm x 7 mm ID from Agilent Technologies) and three detectors (differential refractometer and viscometer, and light scattering). 200 qL of a sample solution at a concentration of 8 mg mL⁻¹ were eluted in 1,2,4-trichlorobenzene at 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⁻¹). OmniSEC software was used for data acquisition and analysis. The number-average molar masses (Mn) and mass-average molar masses (Mw) of the synthesized polyethylenes were calculated using a calibration curve obtained from standard polyethylenes (Mp: 338, 507, 770, 1890, 17000, 27300, 43400, 53100, 65700, 78400 g mol') from Polymer Standard Service (Mainz).

[0130] THF size exclusion chromatography (SEC-THF) for characterizing ethylene and 1,3-butadiene copolymers: Size exclusion chromatography analyses were performed using a Viscotek instrument (Malvern Instruments) equipped with three columns (SDVB, 5 µm, 300 x 7.5 mm Polymer Standard Service), a guard column, and three detectors (differential refractometer and viscometer, and light scattering). One mL of a 5 mg mL sample solution in THF was filtered through a 0.45 µm PTFE membrane. 100 µL of this solution were eluted in THF at a flow rate of 0.8 mL min⁻¹ at 35 °C. OmniSEC software was used for data acquisition and analysis. The number molar masses ( and mass molar masses (Mw) of the synthesized ethylene and 1,3-butadiene copolymers and their dispersity (£>) were calculated using a universal calibration curve obtained from standard polystyrenes (Mp: 1,306 to 2,520,000 g mol') from Polymer Standard Service (Mainz).

[0131] Nuclear magnetic resonance (NMR): 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 probe for the proton and on a Bruker 400 Avance II spectrometer operating at 400 MHz equipped with a 10 mm PSEX 13C probe for carbon. Acquisitions were made in a mixture of tetrachloroethylene (TCE) and deuterated benzene (C6D6) (2:1 v / v) at 363 K for ethylene homopolymers, and in deuterated chloroform (CDC13) at 298 K for ethylene and 1,3-butadiene copolymers. Samples were analyzed at a concentration of 1 wt% for the proton and 5 wt% for the carbon. Chemical shifts are given in ppm, relative to the proton signal. deuterated benzene fixed at 7.16 ppm (respectively deuterated chloroform at 7.26 ppm) and the TCE carbon signal fixed at 120.65 ppm.

[0132] Polymer preparation:

[0133] Metallocene [{Me2SiFlu2Nd(p-BH4)2Li(THF)}]2 is prepared according to the procedure described in patent application WO 2007054224. BOMAG butyl methylmagnesium (20% in heptane, at 0.88 mol L1) comes from Chemtura and is stored in a Schlenk tube under an inert atmosphere. Unless otherwise stated, magnesium halides are sourced from Sigma-Aldrich. The ethylene, of N35 grade, comes from the company Air Liquide and is used without prior purification. 1,3-Butadiene is purified over alumina guards. Toluene and methylcyclohexane are purified over alumina guards. 4-Methoxybenzonitrile is derived from Sigma-Aldrich. In the operating procedures described, "cannulating" means transferring using a cannula.

[0134] Synthesis of functional polyethylenes with ketone at the chain end:

[0135] Example PE1: 198 mL of toluene, taken from a solvent fountain (SPS800 MBraun), is introduced into a 250 mL inert flask fitted with a magnetic stir bar. 2.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether is added to the flask while stirring. 8.0 mg (12.5 µmol neodymium) of {(Me₂Si(Ci₃H₈)₂)Nd(p-BH₄)[(p-BH₄)Li(THF)]}₂ is then added to 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 bar with ethylene, while the temperature is simultaneously raised to 80 °C. The pressure is maintained constant in the reactor using a reservoir containing ethylene.When the desired amount of ethylene has been consumed, here after 15 min, the reactor is degassed and 10 mL (5%) of the polymer solution is cannulated out of the reactor, then the polymer thus collected is precipitated in methanol, recovered by filtration and dried under vacuum at 80°C. It is denoted PE1NF. 10 mL of a degassed and sieved 0.38 M benzonitrile in toluene solution (3.8 mmol, 1 molar equivalent of nitrile / carbon-Mg bond) is added to the polymer solution remaining in the reactor. After 40 min of stirring at 80 °C, 3 mL of a 15% aqueous hydrochloric acid solution are added to deactivate the system, and the temperature is lowered to 20 °C. The polymer solution is poured onto methanol with stirring to precipitate the polymer. The precipitated polymer is filtered, washed with methanol, and then dried under vacuum at 80 °C and ca- racerized. 4.68 g of PE1F polymer with the formula H-(CH2-CH2)nC(O)-(C6H5) and 0.21 g of PE1NF polymer with the formula H-(CH2-CH2)nH were recovered from the sample taken before the functionalization reaction. The proton NMR spectrum of PE1F polymer (TCE / C6D6 2 / 1 v / v, 400 MHz, 363 K) shows protons in the α position of the ketone formed at δ = 2.70 ppm (triplet, CH3-(CH2-CH2)n-CH2-C(O)-(C6H5)). The functionalization rate in PE1F polymer was calculated by normalizing the sum of the integrals of the chain-end signals in the NMR spectrum to 2. Thus, in PE1F, 93% of the polymer chain ends were functionalized with a ketone. No byproducts were identified by NMR.

[0136] Example PE2: The synthesis of the PE2 polymer is identical to that described in example PE 1, except that the 2.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether are replaced by 2.0 mL of a 2.0 M pentylmagnesium bromide solution in diethyl ether. 4.21 g of PE2F polymer with the formula H-(CH2-CH2)nC(O)-(C6H5) and 0.29 g of PE2NF polymer with the formula H-(CH2-CH2)nH were recovered from the sample taken before the functionalization reaction. In PE2F, 89% of the polymer chain ends were functionalized with a ketone. No byproducts were identified by NMR.

[0137] Example PE3: The synthesis of the PE3 polymer is identical to that described in example PE 1, except that the 2.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether are replaced by 2.0 mL of a 2.0 M pentylmagnesium bromide solution in diethyl ether, the functionalization reaction is carried out by the addition of benzonitrile at a level of 3 molar equivalents of nitrile / carbon-Mg bond function at the end of polymerization and the deactivation reaction is carried out after 10 minutes of stirring at 80 °C. 3.8 g of PE3F polymer with the formula H-(CH2-CH2)nC(O)-(C6H5) and 0.24 g of PE3NF polymer with the formula H-(CH2-CH2)nH were recovered from the sample taken before the functionalization reaction. In PE3F, 93% of the polymer chain ends were functionalized with a ketone. No byproducts were identified by NMR.

[0138] Example PE4: The synthesis of the PE4 polymer is identical to that described in example PE1, except that the 2.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether are replaced by 2.0 mL of a 2.0 M pentylmagnesium bromide solution in diethyl ether, and the functionalization reaction is carried out by adding benzonitrile (3 molar equivalents of nitrile function / carbon-Mg bond) in solution in 5 mL of methyltetrahydrofuran and that the deactivation reaction is carried out after 10 minutes of stirring at 80 °C. 3.97 g of PE4F polymer with the formula H-(CH2-CH2)nC(O)-(C6H5) and 0.29 g of PE4NF polymer with the formula H-(CH2-CH2)nH were recovered from the sample taken before the functionalization reaction. In PE4F, 88% of the polymer chain ends were functionalized with a ketone. No byproducts were identified by NMR.

[0139] Example PE5: The synthesis of the PE5 polymer is identical to that described in example PE 1, except that the 2.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether are replaced by 2.0 mL of a 2.0 M pentylmagnesium bromide solution in diethyl ether and that the functionalization reaction is carried out by the addition of benzonitrile (3 molar equivalents of nitrile / carbon-Mg bond function) in solution in 5 mL of methyltetrahydrofuran and that the deactivation reaction is carried out after 10 minutes of stirring at 90 °C. 4.35 g of PE5F polymer with the formula H-(CH2-CH2)nC(O)-(C6H5) and 0.20 g of PE5NF polymer with the formula H-(CH2-CH2)nH were recovered from the sample taken before the functionalization reaction. In PE5F, 86% of the polymer chain ends were functionalized with a ketone. No byproducts were identified by NMR.

[0140] Example PE6: The synthesis of the PE6 polymer is identical to that described in example PE 1, except that the 2.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether are replaced by 2.5 mL of a solution of 1,5-di(magnesium bromide)pentanediy synthesized in methyltetrahydrofuran and then diluted in 0.4 M toluene (1.0 mmol, 5 mM in toluene) and the functionalization reaction is carried out by the addition of 5 mL of a degassed and sieved 0.38 M benzonitrile solution in toluene (1.9 mmol, 1 molar equivalent of nitrile / carbon-Mg bond function). 3.83 g of PE6F polymer with the formulas (C6H5)-C(O)-(CH2-CH2)nC(O)-(C6H5) (telechelic polymer) or H-(CH2-CH2)nC(O)-(C6H5) (monofunctional polymer) and 0.26 g of PE6NF polymer with the formula H-(CH2-CH2)nH from the sample taken before the functionalization reaction were recovered. In PE6F, 22% of the polymer chain ends were non-functional and 78% of the polymer chain ends had been functionalized with a ketone, corresponding to 42% monofunctional chains and 18% telechelic chains. No byproducts were identified by NMR.

[0141] 1,5-Di(magnesium bromide)-pentanediyl is prepared according to the following procedure: 9.72 g of magnesium (400 mmol, 10 equivalents), 80 mL of MeTHF (64 mL of which was in the dropping funnel), 60 mg of diiodine (0.23 mmol, 0.006 equivalents), and 5.45 mL of 1,5-dibromopentane (40 mmol, 1 equivalent) were used in the synthesis. The glassware used consisted of a 200 mL round-bottom flask and a 100 mL dropping funnel. Once the synthesis of the Grignard reagent was complete, the solution was transferred via a filter cannula into a second inert 200 mL round-bottom flask. This solution was concentrated under vacuum and then diluted in 55 mL of toluene. The pentanediyl group concentration was estimated at 0.4 mol L⁻¹*. This oil is immiscible in methylcyclohexane. Aliquot of concentrated oil: 'H NMR (Toluene-D8 - 500 MHz - 298 K) ô: ppm = 2.21 (quin, J = 7.2 Hz, « b"), 1.88 (quin, J = 7.0 Hz, « c"), 0.11 (t, J = 7.4 Hz, « a"); quin for quintuplet. £6 BrMg " 'MgBr

[0142] Example PE7: The synthesis of the PE7 polymer is identical to that described in example PE 1, except that: - the 198 mL of toluene are replaced by 196 mL of toluene and 2 mL of diethyl ether, - the functionalization reaction is carried out by adding 10 mL of a degassed and molecular sieve-stored solution of 4-methoxybenzonitrile at 0.38 M in toluene (3.8 mmol, 1 molar equivalent of nitrile function / carbon-Mg bond) - and that the deactivation reaction is carried out after 60 min of stirring at 80 °C. 4.17 g of PE7F polymer with the formula H-(CH2-CH2)nC(O)-(C6H4)-OCH3 and 0.23 g of PE7NF polymer with the formula H-(CH2-CH2)nH were recovered from the sample taken before the functionalization reaction. In PE7F, 89% of the polymer chain ends were functionalized with a ketone. No byproducts were identified by NMR.

[0143] Example PE8: The synthesis of the PE8 polymer is identical to that described in example PE7, except that the 2.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether are replaced by 2.0 mL of a 2.0 M pentylmagnesium bromide solution in diethyl ether. 4.27 g of PE8F polymer with the formula H-(CH2-CH2)nC(O)-(C6H4)-OCH3 and 0.16 g of PE8NF polymer with the formula H-(CH2-CH2)nH from the sample taken before the Functionalization reactions are recovered. In PE8F, 82% of the polymer chain ends were functionalized with a ketone. No byproducts were identified by NMR.

[0144] Example PE9: The synthesis of the PE9 polymer is identical to that described in the PE7 example, except that: - the 196 mL of toluene are replaced by 194 mL of toluene, - the 2.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether are replaced by 4.0 mL of a 1.0 M mesitylmagnesium bromide solution in diethyl ether - 2.4 mL of a 1.6 M n-butyl lithium solution in hexane (3.84 mmol, 19.2 mM) are added following the mesitylmagnesium bromide solution and before the introduction of the metallocene, - 20 mL of polymer solution, instead of 10 mL, is taken before the functionalization reaction. - the functionalization reaction is carried out by adding 18.5 mL of a degassed and molecular sieve-stored solution of 4-methoxybenzonitrile at 0.38 M in toluene (7.0 mmol) -and that the deactivation reaction is carried out after 1 h of stirring at 80 °C by pouring the polymer solution onto methanol under stirring to precipitate the polymer. 5.02 g of PE9F polymer with the formula H-(CH2-CH2)nC(O)-(C6H4)-OCH3 and 0.18 g of PE9NF polymer with the formula H-(CH2-CH2)nH were recovered from the sample taken before the functionalization reaction. In PE9F, 35% of the polymer chain ends were non-functional and 52% of the polymer chain ends had been functionalized with a ketone.

[0145] Example PE10: The synthesis of the PE 10 polymer is identical to that described in example PE7, except that: - the 196 mL of toluene are replaced by 194 mL of toluene, - the 2 mL of diethyl ether are replaced by 4 mL of diethyl ether - the 2.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether are replaced by 2.27 mL of a 0.88 M butylmagnesium chloride (BOMAG) solution in hexane - the functionalization reaction is carried out by adding 10 mL of a degassed and molecular sieve-stored solution of 4-methoxybenzonitrile at 0.38 M in toluene (3.8 mmol, 1 molar equivalent of nitrile function / carbon-Mg bond). 4.55 g of PE10F polymer of formula H-(CH2-CH2)nC(O)-(C6H4)-OCH3 and 0.18 g of Polymer PE10NF with the formula H-(CH2-CH2)nH, obtained from the sample taken before the functionalization reaction, is recovered. In PE10NF, 48% of the polymer chain ends are non-functional and 46% of the polymer chain ends have been functionalized with a ketone.

[0146] Example FEW: The synthesis of the PEU polymer is identical to that described in example PE7, except that: - the 196 mL of toluene and the 2 mL of diethyl ether are replaced by 198 mL of toluene, - the 2.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether are replaced by 2.27 mL of a 0.88 M BOMAG solution in hexane 3.65 g of PE11F polymer with the formula H-(CH2-CH2)nC(O)-(C6H4)-OCH3 and 0.24 g of PE1 INF polymer with the formula H-(CH2-CH2)nH were recovered from the sample taken before the functionalization reaction. In PE11F, 44% of the polymer chain ends were non-functional and 49% of the polymer chain ends had been functionalized with a ketone.

[0147] Example PE12: The synthesis of the PE 12 polymer is identical to that described in example PE 1, except that the functionalization reaction is carried out by adding 10 mL of a degassed and sieved solution of 0.38 M valeronitrile in toluene (3.8 mmol, 1 molar equivalent of nitrile function / carbon-Mg bond). 4.48 g of PE12F polymer with the formula H-(CH2-CH2)nC(O)-(C4H9) and 0.27 g of PE12NF polymer with the formula H-(CH2-CH2)nH were recovered from the sample taken before the functionalization reaction. In PE12F, 2% of the polymer chain ends were non-functional and 98% of the polymer chain ends were functionalized with a ketone. No byproducts were visible by NMR.

[0148] Example PE13: The synthesis of the PE 13 polymer is identical to that described in example PE 1, except that: - the 2.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether are replaced by 2.27 mL of a 0.88 M butylmagnesium chloride (BOMAG) solution in hexane - the functionalization reaction is carried out by adding 10 mL of a degassed and sieved molecular sieve solution of 0.38 M valeronitrile in toluene (3.8 mmol, 1 molar equivalent of nitrile function / carbon-Mg bond). 3.59 g of PE13F polymer of formula H-(CH2-CH2)nC(O)-(C4H9) and 0.26 g of Polymer PE13NF with the formula H-(CH2-CH2)nH, obtained from the sample taken before the functionalization reaction, is recovered. In PE13NF, 51% of the polymer chain ends are non-functional and 43% of the polymer chain ends have been functionalized with a ketone.

[0149] The polymerization conditions of ethylene are given in Table 1. Table 1 also shows, for each example, the average catalytic activity expressed in kg mol⁻¹ h⁻¹. The characteristics of the synthesized polyethylenes are shown in Table 2.

[0150] Synthesis of functional ketone copolymers of ethylene and butadiene at the chain end:

[0151] Example EBR1: 199 mL of toluene, taken from a solvent fountain (SPS800 MBraun), is introduced into a 250 mL inert flask fitted with a magnetic stir bar. 1.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether is added to the flask while stirring. 32.0 mg (50 pmol neodymium) of {(Me2Si(Ci3H8)2)Nd(p-BH4)[(p-BH4)Li(THF)]}2 is then added to 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 bar with an 80 / 20 mol / mol ethylene / butadiene mixture, and the temperature is simultaneously raised to 80 °C. The pressure is maintained constant in the reactor using a reservoir containing an 80 / 20 mol / mol ethylene / butadiene gas mixture. When the desired quantity of monomers has been consumed, in this case after 35 minutes, the reactor is degassed and the temperature is lowered to 20 °C.10 mL (5%) of the polymer solution are cannulated out of the reactor, then the polymer is precipitated in methanol containing 2,6-di-tert-butyl-4-methylphenol, washed with methanol and dried under vacuum at 80°C. It is designated EBR1NF. Five mL of a degassed, sieved 0.38 M 4-methoxybenzonitrile solution in toluene (1.9 mmol, 1 mol equivalent of nitrile / carbon-Mg bond) are added to the remaining polymer solution in the reactor. After 1 h of stirring at 80 °C, 3 mL of 15% aqueous hydrochloric acid are added to deactivate the system. The polymer solution is poured onto methanol with stirring to precipitate the polymer. The precipitated polymer is filtered, washed with methanol, then dried under vacuum at 80 °C and characterized. 2.92 g of EBR1F polymer and 0.17 g of EBR1NF polymer were recovered from the sample taken before the functionalization reaction. The proton NMR spectrum of the EBR1F polymer (CDC13, 400 MHz, 298 K) allows observation of the methylene protons in the α position of the different ketones formed at δ = 2.5–3.8 ppm as a function of the structure of the monomer units constituting the end chain of the The polymer to which the CO group of the ketone functional group, OCR protons, and C(O)-C6H4-OCH3 aromatic protons are attached. A number-average molar mass is calculated by NMR assuming 100% functionalization. The functionalization rate in the EBR1F polymer is calculated by dividing the molar mass determined by size-exclusion chromatography by that calculated by NMR. Thus, in EBR1F, 49% of the polymer chain ends have been functionalized with a ketone.

[0152] Example EBR2: The synthesis of the EBR2 polymer is identical to that described in the EBR1 example, except that: - the 199 mL of toluene are replaced by 197 mL of toluene, - 1.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether is replaced by 2.1 mL of a 1.0 M mesitylmagnesium bromide solution in diethyl ether, - 1.25 mL of a 1.6 M n-butyl lithium solution in hexane (2.0 mmol, 10.0 mM) is added before the introduction of the metallocene, - the functionalization reaction is carried out by adding 10.25 mL of a degassed and molecular sieve-stored solution of 4-methoxybenzonitrile at 0.38 M in toluene (3.9 mmol) - the deactivation reaction is carried out after 1 h of stirring at 80 °C by pouring the polymer solution onto methanol under stirring to precipitate the polymer. 3.94 g of EBR2F polymer and 0.17 g of EBR2NF polymer were recovered from the sample taken before the functionalization reaction. In EBR2F, 30% of the polymer chain ends were functionalized with a ketone.

[0153] Example EBR3: The synthesis of the EBR3 polymer is identical to that described in the EBR1 example, except that the 1.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether is replaced by 1.14 mL of a 0.88 M BOMAG solution in hexane (1.0 mmol, 5 mM in the toluene / hexane mixture). 4.04 g of EBR3F polymer and 0.20 g of EBR3NF polymer were recovered from the sample taken before the functionalization reaction. In EBR3F, 27% of the polymer chain ends were functionalized with a ketone.

[0154] Example EBR4: The synthesis of the EBR4 polymer is identical to that described in the EBR1 example, except that the butadiene is previously purified by being condensed in a bulb in the presence of trioctylaluminium. 3.51 g of EBR4F polymer and 0.19 g of EBR4NF polymer were recovered from the sample taken before the functionalization reaction. In EBR4F, 57% of the polymer chain ends have been functionalized with a ketone.

[0155] Example EBR5: The synthesis of the EBR5 polymer is identical to that described in the EBR4 example, except that the functionalization reaction is carried out by the addition of 4-methoxybenzonitrile at a level of 3 molar equivalents of nitrile / carbon-Mg bond function. 3.4 g of EBR5F polymer and 0.17 g of EBR5NF polymer were recovered from the sample taken before the functionalization reaction. In EBR5F, 62% of the polymer chain ends were functionalized with a ketone.

[0156] Example EBR6: The synthesis of the EBR6 polymer is identical to that described in the EBR1 example, except that: - the 199 mL of toluene are replaced by 280 mL of methylcyclohexane taken from the solvent fountain (SPS800 MBraun), - 1.0 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether is replaced by 0.125 mL of a 2.0 M butylmagnesium chloride solution in diethyl ether - the 32 mg of metallocene are replaced by 40.0 mg (62.5 qmol as neodymium) of {(Me2Si(C13H8)2)Nd(p-BH4)[(p-BH4)Li(THF)]}2 - The 250 mL reactor is replaced by a 500 mL reactor - there is no sampling before the functionalization reaction, - the functionalization reaction is carried out by adding 10 mL of a degassed and molecular sieve-stored solution of 4-methoxybenzonitrile at 0.025 M in methylcyclohexane (0.25 mmol, 1 molar equivalent of nitrile function / carbon-Mg bond). 13.97 g of EBR6F polymer are recovered. 36% of the polymer chain ends were functionalized with a ketone.

[0157] Example EBR7: The synthesis of the EBR7 polymer is identical to that described in the EBR6 example, except that at the end of polymerization, the functionalization reaction is carried out by adding 10 mL of a degassed and molecular sieve-stored solution of 4-dimethylaminobenzonitrile at 0.025 M in methylcyclohexane (0.25 mmol, 1 molar equivalent of nitrile function / carbon-Mg bond). 12.14 g of EBR7F polymer were recovered. 42% of the polymer chain ends were functionalized with a ketone.

[0158] The copolymerization conditions of ethylene and 1,3-butadiene are given in Table 3. Table 3 also shows, for each example, the average catalytic activity expressed in kg mol⁻¹ h⁻¹. The characteristics of the syn copolymers The theseeds are shown in Tables 4 and 5. The SEC-THF method was used to determine the molar masses of polymers EBR1 to EBR7. The microstructure of the polymers was determined by NMR. The ethylene unit content, the 1,3-butadiene unit content in the 1,2 configuration (1,2 units), in the 1,4 configuration (1,4 units), and the 1,2-cyclohexane motif content (ring units) are expressed as mole percentages relative to all monomer units of the polymer. The synthesized copolymers are statistically significant.

[0159] [Tables 1] Polymer Co-catalyst Mg / Nd Ratio Co-solvent (Et2O / Mg) Time (min) Activity (kg mol1 h1) PE1 C4H9MgCl 320 4.8 21 1 120 PE2 C5HnMgBr 320 4.8 142 130 PE3 C5HnMgBr 320 4.8 115 110 PE4 C5HnMgBr 320 4.8 183 130 PE5 C5HnMgBr 320 4.8 144 130 PE6 BrMgC5HnMgBr 160 0 50 260 PE7 C4H9MgCl 320 9.6 15 1 540 PE8 C5HnMgBr 320 9.6 82 260 PE9 C4H9MgMes 320 9.6 16 1 560 PE10 BOMAG 160 19.2 26 870 PEU BOMAG 160 0 86 190 PE12 C4H9MgCl 320 4.8 17 1 190 PE13 BOMAG 160 0 96 170

[0160] [Tables2] Polymer Chain End Function Rate By-product (%) (*) PE1F CH2-C(O)-C6H5 93 No PE2F 89 No PE3F 93 No PE4F 88 No PE5F 86 No PE6F 78 No PE7F CH2-C(O)-C6H4-OMe 89 No PE8F 82 No PE9F 52 Yes PE10F 46 Yes PE11F 49 Yes PE12F CH2-C(O)-C4H9 98 No PE13F 43 Yes * Measured by 1H NMR

[0161] [Tables3] Polymer Co-catalyst Mg / Nd Ratio Co-solvent (Et2O / Mg) Time (min) Activity (kg mol1 h1) EBR1 C4H9MgCl 40 4.8 35 140 EBR2 C4H9MgMes 42 9.6 35 140 EBR3 BOMAG 20 0 34 140 EBR4 C4H9MgCl 40 4.8 40 140 EBR5 C4H9MgCl 40 4.8 34 140 EBR6 C4H9MgCl 4 4.8 110 120 EBR7 C4H9MgCl 4 4.8 120 120

[0162] [Tables4] Polymer Functionalization agent ^NMR (g mol *) MnSEC (g mol *) D Function rate (%) EBR1NF - 2,000 1.3 - EBR1F CN-(C6H4)-OMe 4,500 2,200 1.4 49 EBR2NF - 2,100 1.3 - EBR2F CN-(C6H4)-OMe 5,900 1,800 1.5 30 EBR3NF - 2,300 1.6 - EBR3F CN-(C6H4)-OMe 8,500 2,300 1.6 27 EBR4NF - 2,900 1.4 - EBR4F CN-(C6H4)-OMe 5 100 2,900 1.4 57 EBR5NF - 2,200 1.3 - EBR5F CN-(C6H4)-OMe 3,900 2,400 1.4 62 EBR6F CN-(C6H4)-OMe 235,000 83,600 1.5 36 EBR7F CN-(C6H4)-NMe2 142,000 59,000 1.3 42

[0163] [Tables5] Polymer Unit ethylene Unit 1.2 Unit 1.4 Cycle Unit EBR1NF 73.3 9.5 6.4 10.8 EBR1F 72.9 9.7 6.5 10.9 EBR2NF 73.4 9.8 6.6 10.2 EBR2F 72.5 10.0 6.8 10.6 EBR3NF 73.2 10.0 6.8 10.0 EBR3F 72.0 10.3 7.2 10.5 EBR4NF 74.8 9.3 6.2 9.8 EBR4F 72.4 9.6 6.5 11.5 EBR5NF 74.1 9.2 6.2 10.5 EBR5F 74.0 9.5 6.3 10.2 EBR6F 81.1 3.0 4.1 11.8 EBR7F 79.6 3.6 4.6 12.2

[0164] Whether the polymers are polyethylenes or ethylene-rich diene copolymers, it is observed that the process according to the invention does indeed lead to the synthesis of ethylene-rich polymers which bear a ketone function at the end of the chain,

[0165] It is also noted that the use of an organomagnesium halide such as butylmagnesium chloride and pentylmagnesium bromide as a co-catalyst allows for the highest levels of ketone function at the chain ends. In the case of the synthesis of functional polyethylenes, it is also noteworthy that the functionalization reaction is selective, since no by-products are formed.

[0166] It is also noteworthy that the process allows the simultaneous introduction into the polymer of a ketone function and a second function distinct from a ketone function, both located at the same end of the polymer chain, without having to resort to an additional functionalizing agent.

Claims

Demands

1. A process for preparing a polymer containing more than 50 mole percent of ethylene units and bearing a ketone functional group at one of its chain ends, which process comprises successive steps a), b), and c) - step a) being the polymerization of a monomeric mixture containing ethylene in the presence of a catalytic system based on at least one metallocene of formula (I) and an organomagnesium compound [P(Cp1)(Cp2)Nd(BH4)II+y)Ly-Ns} (I) Cp1 and Cp2, identical or different, being selected from the group consisting of fluorenyl groups, cyclopentadienyl groups, and indenyl groups, the groups being substituted or unsubstituted, P being a group bridging the two groups Cp1 and Cp2, and comprising a silicon or carbon atom, Nd denoting the neodymium atom, L representing an alkali metal selected from the group consisting of lithium, sodium and potassium, N representing a molecule of an ether, x, an integer or not,being equal to or greater than 0, y, an integer, being equal to or greater than 0, - step b) being the reaction of a compound having a nitrile function with the reaction product of the polymerization of step a), - step c) being a hydrolysis reaction, the polymer being a polyethylene or a copolymer of ethylene and a 1,3-diene and possibly a vinylaromatic compound.

2. A process according to claim 1 wherein the monomer mixture is ethylene, a mixture of ethylene and a 1,3-diene or a mixture of ethylene, a 1,3-diene and a vinylaromatic compound, preferably styrene.

3. A method according to claim 1 or 2 wherein the 1,3-diene monomer is 1,3-butadiene, isoprene, myrcene, 3-farnesene or mixtures thereof.

4. A method according to any one of claims 1 to 3 wherein Cp1 and Cp2, identical or different, are substituted fluorenyl groups or unsubstituted fluorenyl groups of formula Ci3H8, preferably unsubstituted fluorenyl groups.

5. A method according to any one of claims 1 to 4 in which The organomagnesium compound has the formula (lia), (Ilb), (Ile) or (Ild) in which R3, R4, R5, RB, identical or different, represent a carbon group, RA represents a divalent carbon group, X is a halogen atom, m is a number greater than or equal to 1, preferably equal to 1. MgR3R4 (lia) XMgR5 (Ilb) RB-(Mg-RA)m-Mg-RB (Ile) X-Mg-RA-Mg-X (nd).

6. A method according to any one of claims 1 to 5 wherein the organomagnesium compound is a halide of an organomagnesium compound, preferably of formula (Ilb) or (Ild) defined in claim 5.

7. A process according to any one of claims 1 to 6 wherein the organomagnesium compound is a halide of an organomagnesium compound of formula XMgR5, X being a chlorine or bromine atom, R5 an alkyl or aryl.

8. A method according to any one of claims 1 to 7 wherein the compound having a nitrile function contains a single nitrile function.

9. A method according to any one of claims 1 to 8 wherein the compound having a nitrile function is a compound which contains a second function which is selected from the ether, thioether, protected amine, tertiary amine, alkoxysilane and imidazole functions, preferably an ether function, a tertiary amine function, an alkoxysilane function or an imidazole function.

10. A process according to any one of claims 1 to 9 wherein the compound having a nitrile function is an alkane substituted by a nitrile function and by a function which is selected from the ether, thioether, protected amine, tertiary amine and alkoxysilane functions, preferably a tertiary amine or an alkoxysilane function.

11. A process according to any one of claims 1 to 9 wherein the compound having a nitrile function is an arene substituted with a nitrile function, preferably a substituted benzonitrile.

12. A process according to any one of claims 1 to 9 or claim 11 wherein the compound having a nitrile function is a benzonitrile substituted by a function selected from the ether, thioether, protected amine, tertiary amine and imidazole functions, preferably an ether, a tertiary amine or an imidazole function.

13. Polymer containing more than 50 mole percent of ethylene units and bearing on one of its chain ends a ketone function and optionally a second function which is borne on the same chain end as the ketone function and which is selected from the ether, thioether, amine, alkoxysilane, silanol and imidazole functions, which polymer is a copolymer of ethylene and a 1,3-diene or a copolymer of ethylene, a 1,3-diene and a vinylaromatic compound.

14. Polyethylene bearing at one of its chain ends a ketone function and a second function which is borne on the same chain end as the ketone function and which is selected from the ether, thioether, amine, alkoxysilane, silanol and imidazole functions.