NEW TITANIUM-BASED CATALYTIC COMPOSITION FOR THE SELECTIVE TRIMERIZATION OF ETHYLENE TO HEXENE-1

Abstract

The present invention relates to a catalytic composition for the selective oligomerization of ethylene, preferably for the trimerization of ethylene to hexene-1, comprising: - a titanium-based metal precursor corresponding to the following formula:

Description

Title of the invention: NEW TITANIUM-BASED CATALYTIC COMPOSITION FOR THE SELECTIVE TRIMERIZATION OF ETHYLENE TO HEXENE-1 Technical field

[0001] The present invention relates to a novel titanium-based catalytic composition, and its use for the selective oligomerization of ethylene, in particular for the trimerization of ethylene to hexene-1.

[0002] The invention also relates to a process for the oligomerization of ethylene, preferably for the selective trimerization of ethylene into hexene-1, using the catalytic composition according to the invention. Prior art

[0003] Hexene-1 plays a very important role as a reaction intermediate in the chemical and petrochemical industry. Its main use is the production of various grades of polyethylene in which it is used as a co-monomer. This compound is mainly obtained by oligomerization of ethylene. Systems capable of selectively trimerizing ethylene to hexene-1 are today mainly based on chromium (DS McGuinness, Chem. Rev. 2011, 111, 2321). Among the systems known to lead to the selective production of hexene-1, mention may be made of the systems described, for example, in documents US5198563, US5288823, US5382738, EP608447, EP611743, EP614865. These catalysts are prepared from a chromium salt and a metal amide, a pyrrolide in particular. Other catalysts involve an aluminoxane and a chromium complex in association with phosphorus ligands as described in document US5550305.

[0004] Recent work tends to demonstrate the potential of titanium (Ti)-based systems to selectively produce hexene-1. Since the discovery of Deckers et al. In 2001 (Angew. Chem. Int. Ed. 2001, 40, 2516-2519), systems derived from cyclopentadienyl (Cp) ligands activated by methylaluminoxane (MAO) have been very widely described in the literature ([(q5-CpCMe2Ph)TiCl3] / MAO) (Organometallics, 2002, 21, 5122; Organometallics 2002, 21, 5122-5135; J. Am. Chem. Soc. 2009, 131, 5298-5312; Chem. Commun., 2003, 2816-2817; J. Mol. Cat. A.: Chem., 2004, 214, 227-229; WO2012 / 133928; WO2012 / 133929).

[0005] Mitsui also proposes a new titanium-based system for the selective trimerization of ethylene to hexene-1 (EP2174928; Organometallics 2010, 29, 2394-2396). This catalytic system, once activated by MAO (300-10000 eq. / Ti), leads to a C6 selectivity of approximately 92% (including 99.5% of hexene-1).

[0006] The aim of the present invention is to provide a new titanium-based catalytic composition for the selective trimerization of ethylene to hexene-1. Summary of the invention

[0007] The present invention relates to a catalytic composition for the selective oligomerization of ethylene, preferably for the trimerization of ethylene to hexene-1, comprising:

[0008] - a titanium-based metal precursor corresponding to the following formula:

[0009] [Chem.l]

[0010] in which: • L is at least one bond connecting Rx with x chosen between 1 and 12 and Rx with x chosen between 14 and 25, L being a hydrocarbon group having from 1 to 20 carbon atoms (in C1-C20) cyclic or not, aromatic or not, containing or not a heteroelement, or L being a covalent bond, • R1 to R12 on the one hand and R14 to R25 on the other hand, when they are not linked together, are each chosen from a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a substituted or unsubstituted aryl group, a cyclic or uncyclic alkyl group, and a cyclic or uncyclic aralkyl group, said groups having from 1 to 15 carbon atoms (in Cl-Cl 5) and containing or not containing a heteroelement, • R13 and R26 are each chosen from a substituted or unsubstituted aryl group, a cyclic or non-cyclic alkyl group, and a cyclic or non-cyclic aralkyl group, said groups having from 1 to 15 carbon atoms (in Cl-Cl 5) and containing or not a heteroelement, • X1 and X2 are each the same or different heteroatom, and • X3 and X4 are each an identical or different ligand X,

[0011] - and an aluminoxane type activator.

[0012]

[0013]

[0014]

[0015]

[0016]

[0017] DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the expression "between ... and ..." and "between .... and ..." are equivalent and mean that the limit values ​​of the interval are included in the range of values ​​described. If this is not the case and the limit values ​​are not included in the range described, such precision will be provided by the present invention. For the purposes of the present invention, the different parameter ranges for a given step such as pressure ranges and temperature ranges may be used alone or in combination. For example, for the purposes of the present invention, a preferred pressure value range may be combined with a more preferred temperature value range. In the following, particular embodiments of the invention may be described. They may be implemented separately or combined with each other, without limitation of combinations when technically feasible. Titanium-based metal precursor: The term “metal precursor” means: a compound comprising a metal center and at least one stabilizing ligand of the precursor which may be charged or neutral, organic or inorganic. The composition according to the present invention comprises a titanium-based metal precursor corresponding to the formula below: [Chem. 2]

[0018] L is at least one bond connecting Rx with x chosen between 1 and 12 and Rx with x chosen between 14 and 25, L being a hydrocarbon group having from 1 to 20 carbon atoms (in C1-C20) cyclic or not, aromatic or not, containing or not a heteroelement, or L being a covalent bond, R1 to R12 on the one hand and R14 to R25 on the other hand, when they are not connected between they are each chosen from a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a substituted or unsubstituted aryl group, a cyclic or uncyclic alkyl group, and a cyclic or uncyclic aralkyl group, said groups having from 1 to 15 carbon atoms (in Cl-Cl 5) and containing or not containing a heteroelement, • R13 and R26 are each chosen from a substituted or unsubstituted aryl group, a cyclic or non-cyclic alkyl group, and a cyclic or non-cyclic aralkyl group, said groups having from 1 to 15 carbon atoms (in Cl-Cl 5) and containing or not a heteroelement, • X1 and X2 are each the same or different heteroatom, and • X3 and X4 are each the same or different ligand X.

[0019] Advantageously, R2, R4, R5, R6, R7, R8, R9, R10, R11, R12, R15, R17, R18, R19, R20, R21, R22, R23, R24 and R25, when not linked together, are each a hydrogen atom.

[0020] Advantageously, R13 and R26 are each chosen from an alkyl group having from 1 to 6 carbon atoms (C1-C6) containing or not a heteroelement, a cycloalkyl group having from 3 to 6 carbon atoms (C3-C6) containing or not a heteroelement, and a substituted or unsubstituted aryl group having from 6 to 15 carbon atoms (C6-C15) containing or not a heteroelement. Preferably, R13 and R26 are each a methyl group.

[0021] Advantageously, R1, R3, R14 and R16, when not linked together, are each chosen from an alkyl group having from 1 to 10 carbon atoms (C1-C10) containing or not a heteroelement, a cycloalkyl group having from 3 to 10 carbon atoms (C3-C10) containing or not a heteroelement, and a substituted or unsubstituted aryl group having from 4 to 15 carbon atoms (C4-C15) containing or not a heteroelement. Preferably, R1, R3, R14 and R16, when not linked together, are each chosen from a methyl, tert-butyl and adamantyl group.

[0022] Advantageously, X1 and X2 are each an oxygen atom.

[0023] The term "ligand X" means a ligand that has a negative formal charge in the ionic electron counting model. The metal-ligand assembly is described as a ligand X interacting with a metal cation M+, thus giving a purely ionic description of the metal-ligand bond. Ligands X are described for example in the book "The Organometallic Chemistry of the Transition Metals", Sixth Edition, ROBERT H. CRABTREE. Ligands X are also well known to those skilled in the art in the field of organometallic chemistry.

[0024] Advantageously, X3 and X4 are each chosen from fluoride, chloride, bromide, iodide, hydroxide, methyl, n-ethyl, n-propyl, i-propyl, n-butyl, i-butyl, tert-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, tert-butoxy, formate, acetate, propionate and carbonate. Preferably, X3 and X4 are each an identical ligand X selected from chloride, bromide and iodide. Most preferably, X3 and X4 are each a chloride.

[0025] By way of non-limiting example, some structures of titanium-based metal precursors according to the invention are described below:

[0026] [Chem.3]

[0027] In this titanium-based metal precursor structure, L is a phenylene group connecting R3 and R16.

[0028] [Chem.4]

[0029] In this titanium-based metal precursor structure, L is a methylene group linking R7 and R20.

[0030] [Chem. 5]

[0031] In this titanium-based metal precursor structure, L is a bond covalent linking R10 and R23 [Chem. 6] tBu tBu o TiCI3

[0033] In this titanium-based metal precursor structure, L is a covalent bond connecting R2 and R20. Aluminoxane type activator

[0034] The composition according to the present invention comprises an aluminoxane type activator.

[0035] The term “aluminoxane-type activator” means either a soluble aluminoxane compound, or an aluminoxane compound which has been immobilized on a solid support, or a solid aluminoxane compound, or a mixture of these 3 compounds. Soluble aluminoxane

[0036] In one embodiment, the aluminoxane activator is a soluble aluminoxane compound. Preferably, the soluble aluminoxane is selected from methylaluminoxane (MAO), modified methylaluminoxane (MMAO) and ethylaluminoxane. (EAO), alone or in mixture.

[0037] The description of a soluble aluminoxane usable in the catalytic composition according to the invention can be found in the document Eur. J. Inorg. Chem. 2015, 2015, 19-43.

[0038] Preferably, the molar ratio of the aluminum of the soluble aluminoxane to the titanium of the metal precursor, denoted Al^o / Ti, is between 1 and 15,000, preferably between 50 and 10,000, preferably between 250 and 5,000, very preferably between 1,000 and 3,000.

[0039] The AlMA0 / Ti molar ratio is calculated as the ratio between the number of moles of aluminum contained in the soluble aluminoxane and the number of moles of titanium in the metal precursor. Supported aluminoxane

[0040] In one embodiment, the aluminoxane activator is an aluminoxane compound that has been immobilized on a solid support also called supported aluminoxane.

[0041] The supported aluminoxane allows, when using the catalytic composition, the formation of the catalyst via ionic interactions between the titanium-based metal precursor and the supported aluminoxane; such a catalyst structure can be called a floating cation. The catalysis reaction is carried out on the surface or in the pores of the formed catalyst.

[0042] Advantageously, the supported aluminoxane is a methylaluminoxane immobilized on an inorganic support (denoted SMAO). The description of a SMAO usable in the catalytic composition according to the invention as well as its manufacturing process can be found in the work Tailor-Made Polymers Via Immobilization of Alpha-Olefin Polymerization Catalysts, document US2015353658 in the name of KING FAHD PET & MINERALS UNIVERSITY, document US20180354870 in the name of SAUDI ARABIAN OIL COMPANY or document US6211311 in the name of the company EQUISTAR CHEM LP.

[0043] SMAO is advantageously obtained by direct reaction of a MAO solution with an inorganic support in an organic solvent.

[0044] Advantageously, the inorganic support is chosen from silica, alumina, silica-alumina, zeolites, titanium dioxide (TiO2), etc. Preferably, the support is silica. Advantageously, the silica contains Si-OH or Si-O-Si groups.

[0045] In one embodiment, the silica is selected from high purity silicas which do not contain traces of metals. Preferably the silica contains less than 10 ppm of Fe, Na, Al and / or Ti.

[0046] In one embodiment, the silica may have a crystalline, amorphous structure. or partially crystalline. Preferably, the silica has an amorphous structure.

[0047] Advantageously, the inorganic support is in the form of particles defined by an average diameter less than or equal to 200 pm, preferably less than or equal to 150 pm, preferably less than or equal to 100 pm, and very preferably less than or equal to 50 pm.

[0048] In a preferred embodiment, the inorganic support has a granular or spherical morphology. Most preferably, the inorganic support has a spherical morphology.

[0049] In a preferred embodiment, the inorganic support is in the form of particles defined by an average diameter of between 1 and 100 pm, preferably between 10 and 50 pm, preferably between 20 and 40 pm, preferably between 30 and 35 pm.

[0050] In one embodiment, the inorganic support is mesoporous in nature. Preferably, it has an average pore diameter of between 2 and 50 nm, preferably between 10 and 40 nm, more preferably between 15 and 30 nm, and very preferably between 20 and 25 nm. The pore diameter is calculated by the Barrett-Joyner-Halenda (BJH) method and measured by nitrogen adsorption analysis.

[0051] In one embodiment, the inorganic support has a pore volume of between 0.5 and 2.5 mL / g, preferably between 1 and 2 mL / g, more preferably between 1.25 and 1.75 mL / g, and very preferably between 1.4 and 1.6 mL / g. The pore volume is calculated by the Barrett-Joyner-Halenda (BJH) method, and measured by nitrogen adsorption analysis.

[0052] In one embodiment, the inorganic support has a specific surface area of ​​between 1 and 600 m2 / g, preferably between 100 and 500 m2 / g, more preferably between 200 and 400 m2 / g, and very preferably between 300 and 350 m2 / g. The specific surface area is calculated by the Brunauer-Emmett-Teller (BET) method, and measured by nitrogen adsorption analysis.

[0053] Advantageously, the aluminum content of the SMAO is between 1 and 25% by mass, preferably between 5 and 15% by mass, more preferably between 8 and 12% by mass, very preferably between 9 and 11% by mass, relative to the total mass of the SMAO. This ensures that the SMAO will have good properties such as the ability to prevent leaching of the catalyst into the solution.

[0054] Advantageously, the molar ratio of the aluminum of the SMAO to the titanium of the metallic precursor, denoted AlSMAo / Ti, is between 50 and 5000, preferably between 100 and 2500, very preferably between 100 and 1000.

[0055] The AlSMAo / Ti molar ratio is calculated as the ratio between the number of moles of aluminum contained in the SMAO and the number of moles of titanium in the metal precursor. Solid aluminoxane

[0056] In one embodiment, the aluminoxane activator is a solid aluminoxane compound.

[0057] Advantageously, the solid aluminoxane compound is a solid methylaluminoxane also called solid MAO.

[0058] The description of a solid MAO usable in the catalytic composition according to the invention as well as its manufacturing process can be found in documents US20110282017, US2015057418 or US2018355077 in the name of the company TOSOH FINECHEM CORPORATION, or document US6518445 in the name of the company ALBEMARLE CORPORATION.

[0059] Solid MAO by definition is a particulate compound which, at room temperature (30°C or lower), is in the form of a solid suspension in hydrocarbon solvents (aromatic or paraffinic), such as, for example, toluene, cyclohexane, pentane, heptane, etc. Any solid MAO insoluble in a hydrocarbon solvent can act as an activator according to the invention.

[0060] The solid MAO advantageously comprises polymer chains (denoted PM AO) formed by atoms of Al, O and methyl groups (-Me or -CH3) defined by the formula below:

[0061] -[(Me)A10]n-

[0062] of which n can advantageously take a value between 1 and 60, preferably between 10 and 50.

[0063] The solid MAO essentially comprises PMAO chains according to the above formula, but may also comprise in its structure trimethylaluminium (noted TMA) associated, free or in interaction with the PMAO chains. The PMAO may have a linear, cyclic or branched structure, as long as the polymer chains satisfy the above formula.

[0064] The solid MAO used in this invention may contain PMAO of linear and / or branched structure, but also cyclic fragments and residual molecules of the solvent interacting with the TMA.

[0065] Advantageously, the mass aluminum content of the solid MAO is between 36 and 52% by mass. This ensures that the solid MAO will have good properties such as an optimal size and resistance to fragmentation during the various synthesis stages.

[0066] Preferably, the solid MAO is defined by an aluminum content of between 38 and 43% by mass. Preferably, the solid MAO contains an aluminum content of between 40 and 42% by mass. Very preferably, the solid MAO contains an aluminum content of between 40.5 and 41.5% by mass.

[0067] Advantageously, the solid MAO is in the form of particles defined by a average diameter less than or equal to 200 μm, preferably less than or equal to 150 μm, preferably less than or equal to 100 μm, and very preferably less than or equal to 50 μm.

[0068] In a preferred embodiment, the solid MAO is in the form of particles defined by an average diameter of between 1 and 50 pm, preferably between 5 and 40 pm, preferably between 10 and 30 pm, preferably between 15 and 25 pm.

[0069] Advantageously, the molar ratio of solid MAO to the titanium-based metal precursor, denoted Al^os / Ti, is between 1 and 10,000, preferably between 25 and 5,000, preferably between 50 and 2,500, very preferably between 100 and 1,500.

[0070] The Al^os / Ti molar ratio is calculated as the ratio between the number of moles of Aluminum contained in the solid MAO and the number of moles of titanium contained in the metallic precursor.

[0071] Optional additive in the form of an aluminum-based compound

[0072] In one embodiment, the composition according to the present invention further comprises an additive in the form of an aluminum-based compound.

[0073] In one embodiment, the additive in the form of an aluminum-based compound is a compound of formula AIR(3-a)R'a, in which R and R' are independently selected from a C1-C12 alkyl, a C1-C12 alkoxy or a halogen. Advantageously, a can take the value of 0 or 1. Preferably, R and R' are independently selected from a C1-C10 alkyl, a C1-C10 alkoxy, preferably a C1-C6 alkyl, a C1-C6 alkoxy and a chlorine or bromine atom. Preferably, a takes the value 0. Preferably, R is an alkyl and / or alkoxy group selected from methyl, ethyl, propyl, n-propyl, i-propyl, isopropyl, n-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl and from the corresponding alkyloxy groups. Preferably, R is an alkyl and / or alkoxy group selected from ethyl, propyl, i-propyl, isopropyl, n-butyl, and tert-butyl and from the corresponding alkyloxy groups.

[0074] Preferably, the additive in the form of an aluminum-based compound is chosen from trimethylaluminum (TMA), triethylaluminum (TEA), triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-tert-butylaluminum, trihexylaluminum, trioctylaluminum, diethylethoxyaluminum, dimethylethoxyaluminum, methylaluminum dichloride, ethylaluminum dichloride, dimethylaluminum chloride, diethylaluminum chloride, and ethylaluminum sesquichloride, alone or as a mixture.

[0075] Preferably, the additive in the form of an aluminum-based compound is chosen from trimethylaluminum (TMA), triethylaluminum (TEA) and triisobutylaluminum, alone or as a mixture.

[0076] Preferably, the molar ratio of aluminum to the additive in the form of a aluminum-based compound on the titanium of the metal precursor, noted Aladd / Ti, is between 1 and 1500, preferably between 10 and 1000, preferably between 20 and 500, very preferably between 50 and 300.

[0077] The Aladd / Ti molar ratio is calculated as the ratio between the number of moles of Aluminum contained in the additive in the form of an aluminum-based compound and the number of moles of titanium contained in the metal precursor. Optional solvent

[0078] The catalytic composition according to the invention may further comprise a solvent. A solvent chosen from organic solvents and in particular from saturated, unsaturated, cyclic or non-cyclic hydrocarbons may be used.

[0079] The solvent(s) is (are) advantageously chosen from halogenated solvents and hydrocarbons, saturated or unsaturated, cyclic or not, comprising between 1 and 20 carbon atoms, preferably between 1 and 15 carbon atoms and preferably between 4 and 15 carbon atoms.

[0080] Preferably, the solvent is chosen from isobutane, butane, pentane, hexane, cyclohexane, heptane, methylcyclohexane, dichloromethane, toluene, xylene, dichloroethane, chlorobenzene and dichlorobenzene, pure or as a mixture. Preferably, the solvent is chosen from isobutane, butane, cyclohexane, methylcyclohexane, toluene and xylene. Very preferably, the solvent is cyclohexane.

[0081] In a preferred embodiment, the solvent may advantageously be chosen from the products of the oligomerization reaction. Formulation of the catalytic composition

[0082] The catalytic composition according to the invention can be formulated by preparing a mixture comprising the titanium-based metal precursor, the alu-minoxane type activator and optionally the aluminum-based compound used as an additive in any order.

[0083] Implementation of the composition in an oligomerization process

[0084] Another subject of the invention relates to a process for the oligomerization of ethylene, preferably for the selective trimerization of ethylene into hexene-1, using the catalytic composition according to the invention.

[0085] Advantageously, the feedstock used in the oligomerization process is gaseous ethylene.

[0086] In one embodiment, the ethylene gas may contain up to 5% dihydrogen, preferably less than 3% dihydrogen, most preferably less than 1% dihydrogen.

[0087] Advantageously, the concentration of titanium-based metal precursor used used in the oligomerization process is between 0.01 and 10000 pmol / L, preferably between 0.1 and 1000 pmol / L, very preferably between 1 and 100 pmol / L.

[0088] The method can advantageously be carried out in the presence of a solvent as described previously.

[0089] Advantageously, the oligomerization process is carried out at a total pressure of between 0.1 and 20.0 MPa, preferably between 0.1 and 15.0 MPa, and more preferably between 0.5 and 8.0 MPa, and at a temperature of between 15 and 200°C, preferably between 20°C and 100°C and very preferably between 25°C and 80°C.

[0090] The heat generated by the reaction can be eliminated by any means known to those skilled in the art.

[0091] Advantageously, the process of oligomerization and in particular of trimerization of ethylene into hexene-1 can be carried out continuously.

[0092] In a first embodiment, the constituents of the catalytic composition according to the invention are injected into a stirred reactor by conventional mechanical means or by external recirculation, in which the ethylene reacts, preferably with temperature control.

[0093] In another embodiment, a solution comprising a mixture of the titanium-based metal precursor and the aluminoxane-type activator, and a solution comprising the optional additive in the form of an aluminum-based compound, are separately injected into a stirred reactor by conventional mechanical means or by external recirculation, in which ethylene reacts, preferably with temperature control.

[0094] The catalytic composition can be neutralized downstream of the reactor by any means known to those skilled in the art.

[0095] The following examples illustrate the invention without limiting its scope. EXAMPLES

[0096] Example 1: Synthesis of the titanium-based metal precursor Cl according to the invention:

[0097] The synthesis of Cl requires the following steps to be carried out:

[0098] a) Synthesis of 3-tert-Butylsalicylaldehyde:

[0099] 6.36g (21 l,8mmol, 6eq) of paraformaldehyde and 5.00g (52.5mmol, 1.5eq) of ultra-dry MgCl2 (delivered in an ampoule) are weighed in a glove box into a 250mL flask. 70mL of tetrahydrofuran (THF) and 5.26g (35.0mmol) of 2-tert-Butylphenol are introduced. Stir and add 18.5mL (132.7mmol, 3.75eq) of Triethylamine. Heat at 85°C for 4h. Allow to cool to room temperature (25°C) then add 270mL of dichloromethane. The solution is neutralized in a separating funnel by adding 60mL of 1M HCl. The organic phase is washed with 2x 100mL of saline-saturated water and 100mL of deionized water. The organic phase is dried over Na2SO4, then the volatiles are evaporated. A yellow oil is obtained. The product is purified on a silica column (nC5 / CH2Cl2, 80:20, Rf (retention factor) = 0.55). 4.70g of slightly yellow oil is obtained (q (yield) « 75%).

[0100] The NMR characterization of the 3-tert-Butylsalicylaldehyde compound obtained is as follows:

[0101] H NMR (300 MHz, CDC13): ô = 11.8 (s, 1H), 9.9 (s, 1H), 7.54 (dd, 1H), 7.40 (dd, 1H), 6.95 (t, 1H), 1.43 (s, 9H).

[0102] 13C {>H] NMR (75 MHz, CDC13): ô = 197.2; 161.3; 138.4; 134.2; 132.1; 120.8; 119.3; 35.0; 29.3.

[0103] b) Synthesis of 5-Bromo-3-tert-Butylsalicylaldehyde:

[0104] In a 50mL flask, 2.5g (14.0mmol, leq) of the 3-tert-Butylsalicylaldehyde obtained in step a) and 5 mL of acetic acid. A solution containing 4 mL (78.5 μmol, 5.5 eq) of bromine and 4 mL of acetic acid is then added dropwise. Stir at room temperature for 3 hours. Then 100 mL of dichloromethane is added. The organic phase is washed with 3 x 50 mL of saturated sodium metabisulfite solution (Na2S2O5), 3 x 50 mL of saturated NaHCO3 solution and 3 x 50 mL of saturated salt solution. The organic phase is dried over Na2SO4. The solvent is evaporated. 3.0 g of light yellow solid (q ~ 83%) is obtained.

[0105] The NMR characterization of the compound 5-Bromo-3-tert-Butylsalicylaldehyde obtained is as follows:

[0106] 'H NMR (300 MHz, CDC13): ô = 11.7 (s,lH), 9.8 (s,lH), 7.58 (d,lH), 7.52 (d, 1H), 1.40 (s,9H).

[0107] 13C {*H] NMR (75 MHz, CDC13): ô = 196.15; 160.35; 141.29; 137.14; 133.75; 121.83; 111.28; 35.29; 29.15.

[0108] c) Synthesis of 5,5'-di(3-tert-butyl-2-hydroxy-benzaldehyde)-1,4-Phenyl

[0109] In a 100mL flask, 1.5g (5.8mmol, 1eq) of 5-Bromo-3-tert-Butylsalicylaldehyde obtained in step b), 0.86g (2.61mmol, 0.45eq) of 2-methoxyphenylboronic acid and 0.81g (5.8mmol, 1eq) K2CO3 are weighed. In a glove box, 337mg (0.29mmol, 0.05eq) of Pd[P(Ph)3]4 are weighed. A mixture of Dhné-thoxyethane (DME) / H2O 17 / 5mL degassed for 0.5h with argon is added. The mixture is heated at 100°C for 24h. 30mL of water is added, then extracted with dichloromethane (DCM). Dry over MgSO4 and evaporate the volatiles. The product is purified on a silica column (AcOEt / nC5, 5:95). 350 mg of slightly yellow product (q ~ 14%) is obtained.

[0110] NMR characterization of the compound 5,5'-di(3-tert-butyl-2-hydroxy-benzaldehyde)-1,4-Phenyl obtained is as follows: [YES] *H NMR (300 MHz, CDCl3): ô = 11.81 (s, 2H); 10.00 (s, 2H); 7.81 (d, 2H); 7.65 (m, 6H); 1.50 (s, 18H).

[0112] 13C {'H] NMR (75 MHz, CDC13): ô = 197.3; 160.9; 139.14; 139.09; 133.14; 131.97; 130.05; 127.35; 120.97; 35.23; 29.41.

[0113] d) Synthesis of 2-(2-methoxyphenyl) aniline

[0114] In a Schlenk, 6.09g (35.4mmol) of aniline and 34mL of N,N-dimethylformamide (DMF) are introduced. 11mL of saturated Na2CO3 solution are added. Stirring is carried out for 10 min and then 5.38g of boronic acid (35.4mmol) are added. In another Schlenk, 0.675g (3.8mmol) of PdCl2 and 2.00g (7.6mmol) of triphenyl-phosphine are weighed. Purge by carrying out 3 vacuum / argon cycles and then 5.5mL of dry DMF are added. The solution is stirred for 10 min and then added by cannula into the first Schlenk. The mixture is brought to 90°C overnight. The mixture is cooled and then extracted with 3x40mL of AcOEt. The volatiles are evaporated and then purified on a silica column (nC5 / AcOEt, 90:10). 3.75g of white solid (q ~ 53%) is obtained.

[0115] The NMR characterization of the compound 2-(2-methoxyphenyl)aniline obtained is as follows:

[0116] 'H NMR (CH2C12): 7.38 (td, 1H), 7.23 (dd, 1H), 7.15 (td, 1H), 7.10-7.00 (m, 3H), 6.83-6.72 (m, 2H), 3.81 (s, 3H), 3.68 (br s, 2H).

[0117] 13C NMR {*H] (CH2C12): 157.2; 145.2; 132.1; 131.5; 129.4; 128.8; 128.7; 125.4; 121.4; 118.5; 115.8; 111.6; 55.9.

[0118] e) Synthesis of the intermediate compound 1 of the following formula:

[0119] [Chem.7]

[0120] In a schlenk, we weigh 316.3 mg (0.73 mmol; leq) of 5,5'-di(3-tert-butyl-2-hydroxy-benzaldehyde)-l,4-Phenyl obtained in step c), 324.6mg (1.62mmol; 2.2eq) of 2-(2-methoxyphenyl)aniline obtained in step d), a spatula tip of para-toluenesulfonic acid and 15mL of EtOH. Heat at 95°C for 2 nights. Filter and wash with nC5. 378.7mg of orange / red solid is obtained (q ~ 65%).

[0121] The NMR characterization of the intermediate compound 1 obtained is as follows:

[0122] 'H NMR (300 MHz, CD2C12): ô = 13.69 (br s; 2H); 8.66 (s; 2H); 7.67 (d; 2H); 7.63 (s; 4H); 7.53-7.43 (m,4H); 7.43-7.33 (m.6H); 7.30 (d; 2H); 7.25 (dd; 2H); 7.04 (td; 2H); 6.98 (d; 2H); 3.74 (s; 6H); 1.43 (s; 18H).

[0123] f) Synthesis of the titanium-based metallic precursor Cl of the following formula:

[0124] [Chem.8]

[0125] In a Schlenk, 300.0 mg (0.38 mmol) of the intermediate compound 1 obtained in step e), 4 mL of toluene and 4 mL of dichloromethane are introduced. This solution is added by cannula to a solution containing 9 mL of toluene and 0.9 mL of TiCl4 at 1 M in CH2C12 (0.9 mmol) cooled to -78 ° C. The mixture is allowed to return to room temperature. After 2 hours of stirring, the volatiles are evaporated. The complex is washed with 3 x 1 Om L of nC5. Vacuum is drawn at 45 ° C for 2 hours to dry the solid. 335 mg of red-brown solid (q ~ 80%) is obtained.

[0126] The NMR characterization of the obtained titanium Cl-based metal precursor is as follows:

[0127] 'H NMR (300 MHz, CD2C12): ô = 8.27 (s, 2H); 7.90 (d, 2H); 7.62 (s, 4H); 7.59 (d, 2H); 7.56-7.50 (m, 4H); 7.45-7.36 (m, 6H); 7.36-7.27 (m, 4H); 7.25-7.10 (m, 2H); 4.36 (s, 6H); 1.57 (s.18H).

[0128] 13C NMR {*H] NMR (75 MHz, CD2C12): ô = 169.2; 163.2; 158.5; 151.9; 139.1; 137.7; 136.5; 133.4; 131.7; 131.6; 131.3; 131.0; 130.5; 130.3; 129.6; 129.4; 128.9; 128.6; 127.9; 127.85; 127.8; 126.1; 125.7; 123.4; 72.7; 35.7; 29.9.

[0129] Example 2: Synthesis of the titanium-based metal precursor C2 according to the invention:

[0130] The synthesis of C2 requires the following steps to be carried out:

[0131] a) Synthesis of 3,3'-dibromo-4,4'-dimethoxybiphenyl

[0132] In a 100mL flask, 1.17g (5.46mmol, 1eq) of 4,4'-dimethoxybiphenyl are weighed. 29mL of glacial acetic acid are added. 0.6mL (11.7mmol, 2.15eq) of dibromine are added. Heat for 1h at 120°C. Allow to cool to tem room temperature and then the product formed is filtered. It is washed with 2x2mL of glacial acetic acid. 1.1g of white solid is obtained (q ~ 54%).

[0133] The NMR characterization of the 3,3'-dibromo-4,4'-dimethoxybiphenyl obtained is as follows:

[0134] H NMR (300 MHz, CDC13): ô = 7.68 (d, 1H); 7.37 (dd, 2H); 6.90 (d, 2H); 3.90 (s, 6H).

[0135] 13C {>H] NMR NMR (75 MHz, CDC13): ô = 155.3; 133.4; 131.5; 126.7; 112.2; 112.1; 56.4.

[0136] b) Synthesis of 3,3'-di(2-aminophenyl)-4,4'-dimethoxybiphenyl

[0137] In a 100 mL flask, 0.60 g (1.61 mmol, 0.45 eq) of 3,3'-dibromo-4,4'-dimethoxybiphenyl obtained in step a), 0.78 g (3.56 mmol, 1 eq) of 2-pinacol ester of aminobenzeneboronic acid and 0.49 g (3.56 mmol, 1 eq) of K2CO3 are weighed. In a glove box, 207 mg (0.179 mmol, 0.05 eq) of Pd[P(Ph)3]4 are weighed. A DME / H2O mixture (10 / 3 mL) degassed for 0.5 h with argon is added. The mixture is brought to 100°C overnight. 20 mL of water is added, then extracted with DCM. Dry over MgSO4 and evaporate the volatiles. The product is purified on a silica column (nC5 / DCM). 400 mg of orange-white solid (q«62%) is obtained.

[0138] The NMR characterization of the obtained 3,3'-di(2-aminophenyl)-4,4'-dimethoxybiphenyl is as follows:

[0139] 'H NMR (300 MHz, CD2C12): ô = 7.60 (dd, 2H), 7.47 (d, 2H), 7.15 (td, 2H), 7.10 (dd, 2H), 7.08 (d, 2H), 6.79 (td, 2H), 6.75 (dd, 2H), 3.84 (s, 6H), 3.73 (br s, 4H).

[0140] 13C NMR {*H] NMR (75 MHz, CD2C12): ô = 156.4; 145.2; 133.7; 131.5; 130.4; 129.0; 128.9; 127.3; 125.3; 118.5; 115.8; 112.0; 56.2.

[0141] c) Synthesis of the intermediate compound 2 of the following formula:

[0142] [Chem.9]

[0143] In a Schlenk, 319mg (0.80mmol, leq) of 3,3'-di(2-aminophenyl)-4,4'-dimethoxybiphenyl obtained in step b), 415mg (1.77mmol, 2.2eq) of 3,5-Di-tert-butyl-2-hydroxybenzaldehyde and 15mL of dry ethanol. The mixture is heated at 95°C overnight. It is filtered and washed with 3mL of ethanol and 3mL of nC5. Dry under vacuum at 40°C. 510mg of orange solid Cq«76%) is obtained.

[0144] The NMR characterization of the intermediate compound 2 obtained is as follows:

[0145] 'H NMR (300 MHz, CD2C12): ô = 13.4 (br s; 2H); 8.54 (s; 2H); 7.57 (dd; 2H); 7.50-7.28 (m; 10H); 7.24 (d; 2H); 7.18 (d; 2H); 7.00 (d; 2H); 3.77 (s; 6H); 1.32 (s; 18H) 1.29 (s; 18H).

[0146] 13C NMR {*H] NMR (75 MHz, CD2C12): ô = 163.9; 158.5; 156.2; 147.8; 140.7; 137.1; 134.5; 133.4; 131.7; 130.3; 129.1; 129.0; 128.1; 127.5; 127.1; 126.7; 118.8; 118.4; 111.3; 55.7; 35.3; 34.4; 31.6; 29.5.

[0147] d) Synthesis of the titanium-based metal precursor C2 of the following formula:

[0148] [Chem. 10]

[0149] In a Schlenk, 250 mg (0.30 mmol) of intermediate compound 2 obtained in step c) and 5 mL of toluene are introduced. This solution is added by cannula to a solution containing 8 mL of toluene and 0.75 mL of TiCl4 at 1 M in CH2C12 (0.75 mmol) cooled to -78 ° C. The mixture is allowed to return to room temperature. After 2 hours of stirring, the volatiles are evaporated. The complex is washed with 3 x 10 mL of nC5. Vacuum is applied at 45 ° C for 2 hours to dry the solid. 280 mg of orange-brown solid (q ~ 82%) is obtained.

[0150] The NMR characterization of the obtained titanium-based metal precursor C2 is as follows:

[0151] 'H NMR (300 MHz, CDC13): ô = 8.21 (s, 2H); 7.72 (d, 2H); 7.68-7.59 (m, 2H); 7.59-7.38 (m, 10H); 7.37-7.29 (m, 2H); 7.19-7.09 (m, 2H); 4.40 (s, 6H); 1.51 (s, 18H); 1.29 (s, 18H).

[0152] Example 3: Process for the preparation of a SMAO at 10.1% wt. Al.

[0153] In a Schlenk, in a glove box, 3 g of polymerization silica (Average diameter = 33 pm; Average pore diameter DP = 21 nm; Pore volume VP = 1.56 mL / g; Specific surface SBet = 315 m2 / g) are weighed, previously dried at 80°C under vacuum for 2 hours.

[0154] Under argon flow, the silica is impregnated with 4.7 mL (corresponding to the total pore volume) of dry toluene. 13 mL of MAO in toluene (4.65% wt Al, d = 0.895 g / mL, 0.54 g Al theoretical). The mixture becomes a translucent liquid gel.

[0155] The mixture is heated at 80°C for 4 hours with manual stirring every 15 minutes. After 4 hours, the toluene is evaporated and the resulting white powder is dried under vacuum at 80°C for 1 hour.

[0156] The Al content in SMAO is determined by ICP-AES: %wt Al = 10.1 ± 0.5%.

[0157] Example 4: Ethylene trimerization process, using the titanium-based metal precursor Cl activated by a soluble MAO (3000 eq. / Ti)

[0158] In a 100 mL reactor previously purged with argon, 43 mL of toluene are introduced, as well as 5 mL of a solution of MAO soluble at 1.2 mol / L in toluene obtained from a 10% by weight solution in toluene. 2 mL of a solution of the titanium-based metal precursor Cl of Example 1, previously diluted in toluene at 1 mmolTi / L (molar ratio AlMAo / Ti = 3000), are then introduced. The reactor is pressurized under 0.5 MPa of ethylene and the temperature is raised to 30°C with gentle stirring ("250 rpm). When the temperature reaches 28°C, the reactor pressure is adjusted to the desired pressure of 1000 IMPa and the stirring speed is increased to 1000 rpm, marking the start of the catalytic test.

[0159] The reaction temperature is maintained at 30°C and the pressure at a constant value of IMPa. After 30 minutes of reaction, the reactor is cooled to 15°C before being slowly depressurized. The contents of the reactor are collected in a flask and weighed. The organic phase is neutralized with a 10% wt. aqueous solution of H2SO4 and then analyzed by gas chromatography (GC). The solid (polyethylene) is dried at 100°C overnight and then weighed.

[0160] Example 5: Process for the trimerization of ethylene, using the titanium-based metallic precursor C2 activated by soluble MAO (3000 eq. / Ti)

[0161] This test is carried out under the conditions described in example 4 except that 2 mol of the titanium-based metal precursor C2 from example 2 are introduced instead of CL

[0162] Example 6: Process for the trimerization of ethylene, using Cl activated by a SMAO (molar ratio Al5MAn / Ti = 171) with TEA as additive (molar ratio Al^ / Ti = 50).

[0163] 200 mg of SMAO at 9.2% wt. Al (0.68 mmol Al) is introduced into a Schlenk under argon. 2.00 ml of 2.0 mM Cl solution (4 pmol) is added to the Schlenk containing the SMAO. An orange gel forms at the bottom of the Schlenk. The mixture is heated to 50°C for 1 h with manual stirring every 15 min.

[0164] The heating setpoint of the thermostatically controlled bath of the reactor is set to 25°C. Then, 92.0 ml of cyclohexane solvent is introduced into the reactor, the latter having been previously conditioned by introducing an atmosphere of 0.05 MPa of ethylene. Then, the solvent is saturated with ethylene after introducing 0.5 MPa of ethylene gas while stirring at 1500 rpm for one minute. The reactor pressure is lowered to 0.05 MPa and stirring is stopped. 5 ml of nonane dried on molecular sieve (3.6 g) and 1.00 ml of a 0.20 M solution of TEA (0.2 mmol) are introduced. Finally, all of the oligomerization catalyst prepared previously, which is suspended in toluene, is introduced. The ethylene inlet valve (3 MPa pressure) is opened, stirring is started and the reactor heating setpoint is then raised to 28 °C.

[0165] At the end of the test, the ethylene supply is cut off, the medium is cooled to 20°C, then the gas phase is removed through the vent. The reactor is then opened. The liquid is transferred into a flask containing 1.00 ml of 10% H2SO4 solution. A sample of the organic phase is taken and filtered for analysis.

[0166] The results of Examples 4 to 6 are described in the table below.

[0167] [Tables 1] Example Time (h) Productivity (g / gTi-h) C6 (%) 1-C6 (% in C6) C10(%) C10+ (%) PE (%) 4 0.5 161,968 86.1 99.8 11.6 0.6 1.7 5 0.5 182,649 82.7 99.9 15.7 0.7 0.9 6 1.0 103,509 74.8 99.9 19.6 1.3 3.7

[0168] These examples demonstrate that the catalytic compositions according to the invention are functional for the selective production of hexene-1 (obtaining more than 70% of C6 molecules including almost 100% of hexene-1) whether with a soluble alu-minoxane activator or with an aluminoxane activator immobilized on a solid support.

Claims

Claims

1. Catalytic composition for the selective oligomerization of ethylene, preferably for the trimerization of ethylene to hexene-1, including: - a titanium-based metallic precursor corresponding to the following formula: L is at least one bond connecting Rx with x chosen between 1 and 12 and Rx with x chosen between 14 and 25, L being a hydrocarbon group having from 1 to 20 carbon atoms, cyclic or not, aromatic or not, containing or not a heteroelement, or L being a covalent bond, R1 to R12 on the one hand and R14 to R25 on the other hand, when they are not linked together, are each chosen from a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a substituted or unsubstituted aryl group, a cyclic or uncyclic alkyl group, and a cyclic or uncyclic aralkyl group, said groups having from 1 to 15 carbon atoms (in Cl-Cl 5) and containing or not containing a heteroelement, R13 and R26 are each selected from a substituted or unsubstituted aryl group, a cyclic or non-cyclic alkyl group, and a cyclic or non-cyclic aralkyl group, said groups having from 1 to 15 carbon atoms and containing or not a heteroelement, X1 and X2 are each an identical or different heteroatom, and X3 and X4 are each an identical or different ligand X, - and an aluminoxane type activator.

2. The catalytic composition of claim 1, wherein R2, R4, R5, R6, R7, R8, R9, R10, R11, R12, R15, R17, R18, R19, R20, R21, R22, R23, R24 and R25, when not linked together, are each a hydrogen atom.

3. A catalytic composition according to claim 1 or 2, wherein R13 and R26 are each selected from an alkyl group having 1 to 6 carbon atoms whether or not containing a heteroelement, a cycloalkyl group having 3 to 6 carbon atoms whether or not containing a heteroelement, and a substituted or unsubstituted aryl group having 6 to 15 carbon atoms whether or not containing a heteroelement.

4. A catalytic composition according to claim 3, wherein R13 and R26 are each a methyl group.

5. A catalytic composition according to any preceding claim, wherein R1, R3, R14 and R16, when not linked together, are each selected from an alkyl group having from 1 to 10 carbon atoms whether or not containing a heteroelement, a cycloalkyl group having from 3 to 10 carbon atoms whether or not containing a heteroelement, and a substituted or unsubstituted aryl group having from 4 to 15 carbon atoms whether or not containing a heteroelement.

6. A catalytic composition according to claim 5, wherein R1, R3, R14 and R16, when not linked together, are each selected from methyl, tert-butyl and adamantyl.

7. A catalytic composition according to any preceding claim, wherein X1 and X2 are each an oxygen atom.

8. A catalytic composition according to any preceding claim, wherein X3 and X4 are each an identical ligand X selected from chloride, bromide and iodide.

9. A catalytic composition according to any preceding claim, wherein the aluminoxane activator is a soluble aluminoxane compound selected from methylaluminoxane, modified methylaluminoxane and ethylaluminoxane, alone or as a mixture.

10. A catalytic composition according to claim 9, wherein the molar ratio of aluminum in the soluble aluminoxane to titanium in the metal precursor is between 1000 and 3000.

11. A catalytic composition according to any one of claims 1 to 12. 8, wherein the aluminoxane activator is a methylaluminoxane immobilized on an inorganic support.

12. Catalytic composition according to claim 11, wherein the molar ratio of the aluminum of the methylaluminoxane immobilized on an inorganic support to the titanium of the metal precursor is between 100 and 1000.

13. A catalytic composition according to claim 11 or 12, further comprising an additive in the form of an aluminum-based compound selected from trimethylaluminum, triethylaluminum and triisobutylaluminum, alone or as a mixture.

14. A catalytic composition according to claim 13, wherein the molar ratio of aluminum in the additive in the form of an aluminum-based compound to titanium in the metal precursor is between 50 and 300.

15. Process for the selective trimerization of ethylene to hexene-1, using the catalytic composition according to any one of the preceding claims.