FR2968655A1 - METHOD FOR OLIGOMERIZATION OF ETHYLENE IN LINEAR ALPHA-OLEFINS USING A CATALYTIC COMPOSITION BASED ON GROUP 4 ORGANOMETALLIC COMPLEXES GRAFTS ON ANIONS - Google Patents

Abstract

The present invention describes a process for the oligomerization of ethylene to linear alpha-olefins using a catalytic composition comprising: at least one organometallic compound of group 4, supported on anions by means of at least one covalent bond metal-oxygen - at least one aprotic Lewis base, the molar ratio between the aprotic Lewis base and the organometallic compound being between 0.5 / 1 and 20/1 - at least one activating agent, - at least one ionic liquid of formula Q 'A

Description

FIELD OF THE INVENTION The present invention relates to a process for the oligomerization of ethylene to linear alpha-olefins using a catalytic composition based on anion-grafted group 4 organometallic complex. PRIOR ART. -. carbon, used as comonomers for the manufacture of low density polyethylenes (LLDPE) or as an intermediate in the production of detergents or lubricants, are experiencing strong economic growth. Most of the industrial processes for producing alpha olefins are ethylene oligomerization processes catalyzed by transition metal complexes (Ni, Ti, Zr) or AIEt3 (Alpha Olefins Applications Handbook, GR Lapin and JD Sauer Eds ., M. Dekker, NY, 1989). These catalysts operate in a homogeneous phase which makes it difficult to separate the reaction products. Most often, they must be converted at the end of the reaction into insoluble and inactive products which must then be eliminated, which poses problems of rejection.

The use of homogeneous catalysts in ionic liquids is known. When the ionic liquids are not substantially miscible with the reaction products, it is then easy to separate them by simple decantation which makes it possible to recover most of the catalyst.

An article by John S. Wilkes (J.Mol.Cat., 63 (1990) 125-129) describes the reaction of ethylene with Al2Me3Cl3 activated Cp2TiCl2 titanium complexes in a chloroaluminate ionic liquid. The product of the reaction is polyethylene. Under the same conditions, the complexes of zirconium and hafnium proved to be inactive. An article by the same author (Inchem Chem 1990, 29, 3003-3009) describes the reaction of ethylene with the TiOI4 titanium complex activated by AIEtCl 2 in an ionic liquid of the same type. The product of the reaction is also polyethylene.

An article by Wioletta Ochdzan-Siodlak (Eur Polym J., 43 (2007) 3688-3694) describes the reaction of ethylene with the activated Cp 2 TiCl 2 titanium complex by various alkylaluminum activators in the same ionic liquid. The product of the reaction is systematically polyethylene. FR-A-2 918 374 describes organometallic complexes supported on anions comprising at least one covalent metal-oxygen bond. Catalytic compositions employing these complexes and used in olefin oligomerization processes lead to the formation of polyethylene.

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We have now found that, surprisingly, it was possible to use a specific catalytic composition comprising a controlled amount of Lewis base and employing a Group 4 transition metal complex in an ionic liquid, to transform selectively ethylene to alpha-olefins

15 linear. DETAILED DESCRIPTION OF THE INVENTION The present invention describes a process for the oligomerization of ethylene to linear alpha-olefins using a catalytic composition comprising: at least one organometallic compound of general formula AY \ / 2 R ~ m -Y3 ~ e R2 M'-O O + R3 QA at least one aprotic Lewis base, the molar ratio between the aprotic Lewis base and the organometallic compound of general formula A being between 0.5 / 1 and 20/1,

at least one activating agent, at least one ionic liquid of formula Q '+ A-, Q' + being an organic or inorganic cation, identical to or different from Q + and K an organic or inorganic anion.

In the general formula A: - M 'represents boron or aluminum; M represents titanium, zirconium or hafnium; R 1, R 2 and R 3, which may be identical or different, represent organic radicals having from 1 to 30 carbon atoms, for example alkyl groups, which may or may not be saturated or unsubstituted; R 1, R 2 and R 3, which may be identical or different, may also represent hydrocarbon radicals in which one or more hydrogen atoms are replaced by halides or groups comprising at least one heteroelement such as oxygen, nitrogen, sulfur or silicon; R1, R2 and R3, which may be identical or different, may also represent alkoxy, aryloxy or amide groups;

-YI, Y2 and Y3, identical or different, represent halides (F, Cl, Br, I), alkoxy groups, aryloxy groups, or amide groups. Q + represents an organic or inorganic cation;

Thus, by employing a catalyst composition as described above, in which the amount of aprotic Lewis base is limited, it becomes possible to selectively obtain linear alpha-olefins and limit the formation of polyethylene.

The linear alpha-olefins obtained comprise from 4 to 30 carbon atoms.

Most preferably, M is titanium. According to a preferred embodiment, when the metal M of the organometallic compound is titanium, the process according to the present invention selectively leads to the formation of butene-1. Most preferably, M 'is boron.

Preferably, R1, R2 and R3 represent pentafluorophenyl or 3,5- (bistrifluoromethyl) phenyl radicals. Preferably, Y1, Y2 and Y3 represent alkoxy or aryloxy groups.

Preferably, the cation Q + is an organic cation. It is preferably selected from the group of phosphonium, ammonium, guanidinium and / or sulfonium. In the formulas below, X1, X2, X3, X4, X5 and X6 represent hydrogen, preferably a single substituent representing hydrogen, or hydrocarbyl radicals having 1 to 30 carbon atoms, for example unsaturated, saturated or unsaturated alkyl, cycloalkyl or aromatic, aryl or aralkyl groups, optionally substituted.

Very preferably, X1, X2, X3, X4, X5 and X6 represent hydrocarbon radicals having 1 to 30 carbon atoms, for example alkyl groups, saturated or unsaturated, cycloalkyl or aromatic, aryl or aralkyl, optionally substituted.

The sulphonium and guanidinium cations preferably correspond to one of the general formulas SX1X2X3 + or C (NX1X2) (NX3X4) (NX5X6) + where xi, X2, X3, X4, X5 and X6, which are identical or different, are defined as above. The Q + ammonium and / or phosphonium quaternary cations preferably correspond to one of the general formulas NX1X2X3X4 + and PXIX2X3X4 +, or to one of the general formulas X'X2N = CX3X4 +, X1X2P = CX3X4 + and X'X2X3P = N + = PX4X5X6 in which X 1, X 2, X 3, X 4, X 5 and X 6, which may be identical or different, are defined as above. The ammonium and / or phosphonium cations may also be derived from nitrogen and / or phosphorus heterocycles containing 1, 2 or 3 nitrogen and / or phosphorus atoms, of the general formulas: 25 x2 O / 1 x G / x Wherein the rings consist of 4 to 10 atoms, preferably 5 to 6 atoms, and X 1 and X 2, identical or different, are defined as above.

The quaternary ammonium or phosphonium cation may furthermore satisfy one of the general formulas: X'X2 + N = CX3-X'-X3C = N + X1 X2 and X'X2 + P = CX3-X'-X3C = P + X1X2 in which X1, X2 and X3, identical or different, are defined as above, and x 'represents an alkylene or phenylene radical.

Among the X1, X2, X3 and X4 groups, mention will be made of methyl, ethyl, propyl, isopropyl, primary butyl, secondary butyl, tertiary butyl, butyl, amyl, phenyl or benzyl radicals; X 'may be a methylene, ethylene, propylene or phenylene group. By way of example of Q + cations which may be used in the present invention, mention may be made of 1-butyl-3-methylimididazolium, 1-butyl-2,3-dimethylimidazolium, 1-ethyl-3-methylimidazolium, and 1-butyl-3-methylimidazolium. butyl-3-butylimidazolium, N, N-butylmethylpyrrolidinium, tetrabutylphosphonium, tetraphenylphosphonium and bis (triphenylphosphoranylidene) ammonium.

The aprotic Lewis base may be chosen from nitrogenous, oxygenated, sulfurous or phosphorusized Lewis bases. Among the nitrogenous Lewis bases, mention may be made of tertiary amines, substituted pyridines and pyridines, and alkylimidazoles. Among the phosphorus Lewis bases, mention may be made of phosphines, phosphinites, phosphonites or phosphites. Among the oxygen Lewis bases, mention may be made of ethers, cyclic or otherwise. Among the sulfur-containing Lewis bases, mention may be made of thioethers such as thiophenes and its derivatives. The Lewis bases according to the present invention may be functionalized with one or more cationic groups or with one or more anionic groups. For example, the publication Green Chem. 2007 p1097-1103 describes oxygen Lewis bases functionalized with cationic groups; the publication Advanced Synthesis & Catalysis 2005 p1835-1847 discloses phosphorus Lewis bases functionalized with one or more cationic groups; the Angew publication. Chem. Int. Ed. 2008, p1127-1129 discloses nitrogenous Lewis bases functionalized with a cationic group.

Preferably, the aprotic Lewis base will be chosen from cyclic ethers. More preferably, the aprotic Lewis base will be selected from cyclic ethers functionalized with one or more cationic groups or with one or more anionic groups.

An aprotic Lewis base mixture is usable according to the present invention.

Preferably, the molar ratio between the aprotic Lewis base and the organometallic compound A is between 0.5 / 1 and 10/1, preferably between 1/1 and 5/1.

In a preferred manner, the aprotic Lewis base is tetrahydrofuran, also called THF.

Preferably, the molar ratio between the THF and the organometallic compound of general formula A is between 1/1 and 5/1.

The activating agent may be selected from the group consisting of tris (hydrocarbyl) aluminum compounds, chlorinated or brominated hydrocarbylaluminum compounds and aluminoxanes. The tris (hydrocarbyl) aluminum and the chlorinated or brominated hydrocarbylaluminum compounds preferably correspond to the general formula AIR.Z3_X in which R represents a monovalent hydrocarbon radical containing for example up to 12 carbon atoms such as alkyl, aryl, aralkyl , alkaryl or cycloalkyl, Z represents a halogen atom chosen, for example, from chlorine and bromine, Z being preferably a chlorine atom, x is from 1 to 3. Examples of such compounds of formula AIRXZ3_X are mention may be made of ethylaluminum sesquichloride (Et3Al2Cl3), dichloroethylaluminum (EtAlCl2), dichloroisobutylaluminum (iBuAICl2), chlorodiethylaluminum (Et2AlCl) and triethylaluminum (TEA). Among the aluminoxanes that may be used according to the invention, mention may be made of methylaluminoxane (MAO) and modified methylaluminoxane (MMAO). A mixture of activating agents is usable according to the present invention.

The molar ratio between the activating agent and the organometallic compound of general formula A is advantageously between 1/1 and 2000/1, preferably between 1/1 to 500/1 and preferably between 1/1 and 200/1. 1.

In a preferred manner, the activating agent is triethylaluminium. Preferably, the molar ratio between the triethylaluminium and the organometallic compound of general formula A is between 1/1 and 10/1. The ionic liquid Q '+ A - is preferably composed of a cation Q' + defined in the same way as the cation Q + described above, associated with an organic or inorganic anion. The cation Q '+ is identical to or different from Q +. Preferably, Q '+ is an organic cation. The anion K will preferably be chosen from anions halides, nitrates, sulphates, alkyl sulphates, phosphates, alkyl phosphates, acetates, haloacetates, tetrafluoroborate, tetrachloroborate, hexafluorophosphate, trifluoro-tris- (pentafluoroethyl) phosphate, hexafluoroantimonate, fluorosulphonate, alkylsulphonates (by methylsulfonate), perfluoroalkylsulfonates (for example trifluoromethylsulphonate), bis (perfluoroalkylsulphonyl) amides (for example, bis trifluoromethylsulphonyl amide of formula N (CF 3 SO 2) 2), tristrifluoromethylsulphonyl methylide of formula C (CF 3 SO 2) 3, bis-trifluoromethylsulphonyl methylide of the formula HC (CF 3 SO 2) 2- arenesulphonates, optionally substituted by halogen or haloalkyl groups, tetraphenylborate anion and tetraphenylborate anions, the aromatic rings of which are substituted, tetra (trifluoroacetoxy) -borate, bis- (oxalato) -borate, dicyanamide and tricyanom éthylure.

The concentration of the organometallic compound of formula A in the ionic liquid is advantageously between 0.01 mmol per liter of ionic liquid and 100 mmol per liter of ionic liquid, preferably between 0.05 mmol per liter of ionic liquid and 50 mmol per liter of ionic liquid.

Optionally, the catalyst composition may contain a solvent selected from the group of organic solvents. The organic solvents are preferably aprotic solvents. Among the solvents which can be used in the process according to the present invention, mention may be made of hydrocarbons such as pentane, hexane, cyclohexane or heptane, aromatic hydrocarbons such as benzene, toluene, xylenes, chlorobenzene, bromobenzene, fluorobenzene or chlorinated solvents such as dichloromethane. A mixture of organic solvents is usable for the catalytic composition according to the present invention.

The compounds entering into the catalytic composition according to the invention may be mixed in any order. The mixing can be done by simple contact followed by stirring until a homogeneous liquid forms. This mixture can be made outside the oligomerization reactor or, preferably, in this reactor.

Oligomerization reaction.

The catalytic reaction of oligomerization of ethylene to linear α-olefins can be carried out in a closed system, in a semi-open system or continuously, with one or more reaction stages. Vigorous agitation should ensure good contact between the reagent (ethylene) and the catalytic mixture. The reaction temperature may be from -40 ° C to +180 ° C, preferably from -10 ° C to 140 ° C. It is possible to operate above or below the melting temperature of the medium, the dispersed solid state not being a limitation to the smooth running of the reaction. The pressure can range from atmospheric pressure to 70 MPa, preferably from 1 to 10 MPa. The heat generated during the reaction can be removed by any means known to those skilled in the art.

The products of the reaction and the unreacted reagent are separated from the catalytic system by simple decantation and then fractionated.

The following examples illustrate the invention without limiting its scope. 5 EXAMPLES

Abbreviations used in the examples EMIM +: 1-ethyl-3-methylimidazolium FAP: trifluoro-tris- (pentafluoroethyl) phosphate PPN +: bis (triphenylphosphoranylidene) ammonium

Example 1: Preparation of [PPN] + [B (C6F5) 3OH] "A solution of bis (triphenylphosphoranylidene) ammonium chloride (5.025 g, 8.75 mmol) in dichloromethane (25 mL) is added dropwise to a solution of B (C6F5) 3 (4.480 g, 8.75 mmol, 1 eq) in dichloromethane (25 mL) and then the mixture is left under magnetic stirring overnight at room temperature and is then concentrated by half and added to a suspension of anhydrous lithium hydroxide (251 mg, 10.5 mmol, 1.2 eq) in dichloromethane (20 mL) at room temperature After 5 days of stirring, the LiCl precipitate is The salt [PPN] + [B (C 6 F 5) 3 OH] - is obtained as a white powder with a yield of 95%. It is characterized by NMR of fluorine, proton, carbon and boron, by mass spectrometry, IR spectroscopy and elemental analysis. 1H NMR [300.1MHz, CD2Cl2] (8, ppm): 1.67 (s, 1H, OH); 7.40-7.55 (m, 24H, CH 2, m Ph); 7.60-7.70 (m, 6H, CH p Ph).

NMR 11B [96.3 MHz, (CH 2 Cl 2)] (δ, ppm): -4.10 (s).

19F NMR [282.4MHz, CD2Cl2] (8, ppm): -135.8 (d, 6F, 3JFF = 21.6Hz, o-F); -163.0 (t, 3F, 3 JFF = 19.6 Hz, p-F); -166.5 (m, 6F, m-F).

13 C NMR [75.5 MHz, CD 2 Cl 2] (8, ppm): 127.4 (dd, 1 Jpc = 107.9 Hz, P-C); 129.8 (m, m-CH); 132.5 (m, o-CH); 134.1 (t, 4 Jpc = 1.3 Hz, p-CH); 136.7 (doublet of byte, 1JcF = 247 Hz, C-F), 138.4 (doublet of byte, 1JcF = 242 Hz, C-F), 148.3 (doublet of byte, 1JcF = 240 Hz, C-F).

MS-ESI: ESI (+) [M = 538.1849, PPN +]; ESI (-) [M = 528.9887, B (C6F5) 3OH-]. IR: ν (OH) = 3698 cm -1.

AE: Theoretical% C 60.75,% H 2.93,% N 1.31. Experimental% C 60.91,% H 2.95,% N 1.27. Example 2: Preparation of [PPN] + [Ti (OiPr) 3 (OB (C6F5) 3)] [O-Ti-O F] PPN [PPN] + [B (C6F5) 3OH] - (698 mg, 0) 65 mmol), as prepared in Example 1, is suspended in toluene. Ti (OiPr) 4 (196 mg, 0.69 mmol, 1.06 eq.) Is added to the syringe dropwise on the suspension of compound A. After stirring for 24 hours at room temperature, a colorless oil is deposited on the walls of the schlenk. The solvent is evaporated to form a slightly white oil. This oil is then dissolved in 1 mL of dichloromethane and then washed with 2x5 mL of cyclohexane. The solvent is evaporated to give the salt [PPN] + [Ti (OiPr) 3 (OB (C6F5) 3)] - in the form of a colorless oil with a yield of 95% This compound B is characterized by fluorine, proton, carbon and boron and by elemental analysis.

1H NMR [300.1MHz, CD2Cl2] (8, ppm): 1.02 (d, 18H, 3HH = 6.0Hz, CH3 O1Pr); 4.36 (Sep, 3H, 3HH = 6.0 Hz, CH O1Pr); 7.40-7.55 (m, 24H, CH 2, m Ph); 7.60-7.69 (m, 6H, CH p Ph).

NMR 11B [96.3MHz, CD2Cl2] (δ, ppm): -3.40 (s). 19F NMR [282.4 MHz, CD2Cl2] (5 ppm): -133.4 (d, 6F, 3 FFF = 26.2Hz, o-F); -163.6 (t, 3F, 3 JFF = 19.9 Hz, p-F); -167.1 (m, 6F, m-F).

13C NMR [75.5 MHz, CD2Cl2] (8, ppm): 26.5 (CH3 O1Pr); 74.2 (CH O1Pr); 127.4 (dd, 1 Jpc = 108.1 Hz, P-C); 129.8 (m, m-CH); 132.5 (m, o-CH); 134.1 (t, 4 Jpc = 1.4 Hz, p-CH); 136.8 (doublet of multiplet, 1JCF = 243 Hz, CF), 138.6 (doublet of multiplet, 1JcF = 246 Hz, CF), 148.4 (doublet of multiplet, 1JcF = 236 Hz, CF) (C; pS0 is not 1 o detected). AE: Theoretical% C 58.58% H 3.98% N 1.08. Experimental% C 58.40% H 3.85% N 1.16. Example 3 (according to the invention): Selective dimerization of ethylene. In a stainless steel autoclave with a working volume of 110 ml, provided with an electric heating and a vortex cooling system of compressed air to regulate the temperature, is introduced, in order, under atmosphere Argon, 10 ml of cyclohexane, 0.15 mmol of complex [PPN] + [Ti (OiPr) 3 (OB (C6F5) 3)] - as described in the invention previously solubilized in a mixture [EMIM] + [FAP] - (6 mL) / chlorobenzene (1 mL). 0.9 mmol of triethylaluminum in solution in cyclohexane is then introduced, ie a molar ratio AI / Ti = 6, then 0.3 mmol of THF in solution in cyclohexane, ie a molar ratio of THF / Ti = 2. total amount of cyclohexane is 17 mL. Ethylene is then introduced into the autoclave so as to maintain a constant pressure of 4 MPa and set at 40 ° C. After 2h20 of reaction (35g of ethylene consumed), the introduction of ethylene is stopped and the reactor cooled to room temperature. The autoclave is then depressurized. A gaseous fraction is collected which is analyzed by chromatography. The two phases composing the liquid fraction are separated. The organic phase collected is neutralized by injection of 1 mL of sulfuric acid (10% in water) and is then analyzed by chromatography. A small amount of polyethylene is also recovered. The activity and selectivity obtained are reported in Table 1. The consumption of ethylene as a function of time is shown in FIG.

Example 4 (comparative): Selective dimerization of ethylene in the absence of THF.

In a stainless steel autoclave with a working volume of 110 ml, provided with an electric heating and a vortex cooling system of compressed air to regulate the temperature, is introduced, in order, under atmosphere argon, 14 mL of cyclohexane, 0.15 mmol of complex [PPN] + [Ti (OiPr) 3 (OB (C6F5) 3)] - as described in the invention previously solubilized in a mixture [EMIM] + [FAP] - (6 mL) / chlorobenzene (1 mL). 0.45 mmol of triethylaluminum in solution in cyclohexane is then introduced, ie a molar ratio AI / Ti = 3. The total amount of cyclohexane is 17 ml. Ethylene is then introduced into the autoclave so as to maintain a constant pressure of 2 MPa and set at 60 ° C. After 1 hour of reaction, the introduction of ethylene is stopped and the reactor cooled to room temperature. The autoclave is then depressurized. A gaseous fraction is collected which is analyzed by chromatography. The two phases composing the liquid fraction are separated. The organic phase collected is neutralized by injection of 1 mL of sulfuric acid (10% in water) and is then analyzed by chromatography. A small amount of polyethylene is also recovered. The activity and the selectivity obtained are reported in Table 1. The consumption of ethylene as a function of time is shown in FIG.

EXAMPLE 5 (comparative): Selective dimerization of ethylene in the absence of ionic liquid.

In a stainless steel autoclave with a working volume of 35 ml, provided with an electric heating and a vortex cooling system of compressed air for regulating the temperature, is introduced, in the order, under an atmosphere of argon, 0.15 mmol complex [PPN] + [Ti (OiPr) 3 (OB (C6F5) 3)] - as described in the invention previously solubilized in chlorobenzene. 0.9 mmol of triethylaluminum in solution in chlorobenzene is then introduced, that is to say a molar ratio AI / Ti = 6, then 0.3 mmol of THF in solution in chlorobenzene, that is a molar ratio THF / Ti = 2. total chlorobenzene is 6 mL. Ethylene is then introduced into the autoclave so as to maintain a constant pressure of 2 MPa and set at 60 ° C. After one hour of reaction, the introduction of ethylene is stopped and the reactor cooled to room temperature. The autoclave is then depressurized and the catalytic system neutralized by injection of 1 mL of sulfuric acid (10% in water). A gaseous fraction and a liquid fraction are collected which are analyzed by chromatography. A small amount of polyethylene is also recovered.

The activity and the selectivity obtained are reported in Table 1. The consumption of ethylene as a function of time is shown in FIG.

Table 1. Summary of tests carried out with the complex [PPN] + [Ti (OiPr) 3 (OB (C6F5) 3)] "(invention and comparisons) Reference ratio Liquid Activity Distribution (% wt) THF / Ti ionic (g / gTi / h) C4 (a) C6 PE 89 Example 3 2 [EMIM] + [FAPr 1049 9 1 (99+) 73 Example 4 [EMIM] + [FAP] - 546 (99+) 12 12 85 Example 5 2,443 (98) In this table, the activity is defined as the mass of ethylene (C2H4) consumed per gram of initially introduced titanium per hour.The C4 distribution is the amount of olefins having an atomic number The carbon distribution is equal to 4 in the total distribution (a) is the butene-1 linear product selectivity in the C4 cut, and the C6 distribution is the amount of olefins having a carbon number equal to The selectivity for butene-1 linear product in the C4 cut is measured by gas chromatography according to a method known to those skilled in the art.

Claims (16)

REVENDICATIONS1. Process for the oligomerization of ethylene to linear α-olefins using a catalytic composition comprising: at least one organometallic compound of general formula AY \ j2 R ~ m -Y3 \ e R2 M'-O / p + R3 QA at least an aprotic Lewis base, the molar ratio between the Lewis base and the organometallic compound of general formula A being between 0.5 / 1 and 20/1, at least one activating agent, and at least one ionic liquid of formula + A-, Q '+ being an organic or inorganic cation, identical or different from Q + and A- an organic or inorganic anion. M 'representing boron or aluminum; M representing titanium, zirconium or hafnium; R1, R2 and R3, identical or different, representing organic radicals having 1 to 30 carbon atoms, saturated or unsaturated, cycloalkyl or aromatic, aryl or aralkyl, optionally substituted, YI, Y2 and Y3, identical or different, represent halides (F, Cl, Br, I), alkoxy, aryloxy, amide groups; and Q + represents an organic or inorganic cation. 2. The process as claimed in claim 1, in which the radicals R1, R2 and R3, which may be identical or different, are hydrocarbyl radicals in which one or more hydrogen atoms are replaced by halides or groups comprising at least one heteroelement such as atom of oxygen, nitrogen, sulfur or silicon. 3. Method according to one of the preceding claims wherein the cation Q + is an organic cation selected from phosphonium, ammonium, guanidinium and / or sulfonium 4. Method according to one of claims 1 to 3 wherein the metal M represents titanium, M 'represents boron, the radicals RI, R2 and R3 are pentafluorophenyl or 3,5- (bistrifluoromethyl) phenyl radicals, YI, Y 2 and Y 3 are alkoxy or aryloxy groups and Q + is an organic cation selected from phosphonium, ammonium, guanidinium and / or sulfonium. 5. Method according to one of the preceding claims wherein the aprotic Lewis base is selected from nitrogenous, oxygenated, sulfurous or phosphorus bases, preferably from tertiary amines, optionally substituted pyridines, alkylimidazoles, phosphines, phosphinites. , phosphonites, phosphites, ethers, and thioethers. 6. The method of claim 5 wherein the aprotic Lewis base is functionalized with one or more cationic or anionic groups. 7. Method according to one of the preceding claims wherein the molar ratio between the aprotic Lewis base and the organometallic compound A is between 0.5 / 1 and 10/1, preferably between 1/1 and 5/1. 8. Method according to one of the preceding claims wherein the aprotic Lewis base is tetrahydrofuran and the molar ratio between the Lewis base and the organometallic compound of formula A is between 1/1 and 5/1. 9. Method according to one of the preceding claims wherein the activating agent is selected from tris (hydrocarbyl) aluminum compounds, chlorinated or brominated hydrocarbylaluminium compounds and aluminoxanes. 10. Method according to one of the preceding claims wherein the molar ratio between the activating agent and the organometallic compound of formula A is between 1/1 and 2000/1, preferably between 1/1 and 500/1. 11. The method of claim 10 wherein the activating agent is triethylaluminium and the molar ratio between triethylaluminium and the organometallic compound of formula A is between 1/1 and 10/1. 12. Method according to one of the preceding claims wherein the ionic liquid consists of a Q '+ cation and anion A- selected from anions halides, nitrates, sulfates, alkylsulfates, phosphates, alkylphosphates, acetates, haloacetates , tetrafluoroborate, tetrachloroborate, hexafluorophosphate, trifluoro-tris (pentafluoroethyl) phosphate, hexafluoroantimonate, fluorosulfonate, alkylsulfonates, perfluoroalkylsulfonate, bis (perfluoroalkylsulfonyl) amides, tris-trifluoromethylsulfonyl methylide of formula C (CF3SO2) 3-, bis (bis) trifluoromethylsulfonyl of formula HC (CF3SO2) 2-, arenesulfonates, optionally substituted with halogen or haloalkyl groups, tetraphenylborate anion and tetraphenylborate anions whose aromatic rings are substituted, tetra- (trifluoroacetoxy) -borate, bis- ( oxalato) -borate, dicyanamide and tricyanomethylide. 13. Method according to one of the preceding claims wherein the concentration of the organometallic compound of formula A in the ionic liquid is between 0.01 and 100 mmol / L of ionic liquid, preferably between 0.05 and 50 mmol / L . 14. Method according to one of the preceding claims wherein the catalytic composition comprises an aprotic organic solvent. 15. Method according to one of the preceding claims wherein the temperature is between -40 ° C and + 180 ° C and the pressure between atmospheric pressure and 70MPa. 16. Process according to one of the preceding claims, in which the catalytic reaction is carried out in a closed system, in a semi-open system or continuously, with one or more reaction stages.