Novel chromium-based or titanium-based supported catalytic composition

Abstract

The present invention relates to a catalytic composition for the selective oligomerization of ethylene, more particularly for the trimerization and / or tetramerization of ethylene to 1-hexene and / or 1-octene, respectively, comprising:-at least one chromium-based or titanium-based metal precursor; -at least one support in the form of solid methylaluminoxane (MAO); -at least one additive in the form of an aluminum-based compound. Another subject of the invention relates to an oligomerization process, preferably for the selective trimerization and / or tetramerization of ethylene to 1-hexene and / or 1-octene, respectively, using a catalytic composition according to the invention.

Description

TECHNICAL FIELD

[0001] The present invention relates to a novel catalytic composition based on supported chromium or titanium and its use for the selective oligomerization of ethylene, more specifically for the trimerization and / or tetramerization of ethylene into 1 - hexene and / or 1 - octene respectively.

[0002] The present invention also relates to a process for the oligomerization of ethylene using the catalytic composition according to the present invention, preferably for the trimerization and / or tetramerization of ethylene into 1 - hexene and / or 1 - octene respectively. PRIOR ART

[0003] Linear α - olefins (LAOs) containing from 4 to more than 20 carbon atoms are important raw materials for the manufacture of petrochemical intermediates. Despite their wide range of applications, the global demand for LAOs is mainly dominated by short - chain α - olefins, such as 1 - butene, 1 - hexene and 1 - octene, which are used as comonomers in the polymer industry. The global supply of LAOs is mainly met by two classes of ethylene oligomerization processes using homogeneous catalysts: the "full - range" process, which produces a wide distribution of olefins (usually from C4 to C30); and the selective "specialty" processes, which produce only a single α - olefin (1 - butene, 1 - hexene or 1 - octene). However, due to the faster growth rate of the demand for C4 to C10 short - chain LAOs compared to that for the C10+ range, substantial progress has recently been made in controlling the product distribution in favor of a shorter α - olefin distribution, or even the selective production of a single α - olefin. In this field, many advances have been made in recent years in the tetramerization of ethylene to 1 - octene by chromium - based homogeneous catalysts (P.W.N.M. van Leeuwen et al., Coordination Chemistry Reviews 255 (2011) 1499–1517). Systems known to lead to the selective production of 1 - octene include, for example, those described in the literature WO2004056477, WO2004056478 or WO2004056479. These catalysts utilize a Cr(III) - based metal precursor in combination with a PNP ligand (such as Ph 2 PN(iPr)PPh 2 ) and are activated in situ by aluminoxanes (MAO: methylaluminoxane; MMAO: modified methylaluminoxane, etc.). They lead to the "selective" production of 1 - octene (>65% selectivity). Subsequently, further Cr - based catalytic systems have been developed, examples including those in the literature WO2010034102, WO2011156892 or WO2011108772. The trimerization of ethylene to 1 - hexene using titanium - based complexes is also a field with unlimited expansion. Examples include the systems developed by the Dutch Polymer Institute ([(η 5 Cp - CMe2 -C 6 H 5 )TiCl 3 / MAO; Angew Chem Int Ed, 2001, 40, 2516 - 2519) or the system more recently developed by Mitsui ([(ArOImineOMe)TiCl 3 / MAO; Organometallics, 2010, 29, 2394 - 2396).

[0004] The main drawback of chromium - based or titanium - based catalytic systems for ethylene oligomerization is the formation of a large amount of polymer while forming the target olefins (1 - hexene and / or 1 - octene). This formation of polymer may be the reason for the rapid deactivation of the catalyst and the increased difficulty in operating the process. The first approach in this field was inherited from polymer experts (who are used to managing large amounts of polymer in their processes) and involves loading homogeneous catalysts on inorganic supports, especially to control the morphology of the formed polymer. R. Duchateau specifically described the conversion of this strategy to ethylene oligomerization, using silica - supported MAO to selectively trimerize ethylene to 1 - hexene through titanium complexes (ACS Catalysis, 2015, 5, 5068 - 5076). The polymer produced during this conversion is in the form of a non - sticky solid with a controllable morphology, which can significantly reduce reactor fouling.

[0005] The object of the present invention is to provide a novel catalytic composition for ethylene oligomerization, which is not affected by the problems present in traditional, prior - art catalytic compositions, and especially those catalytic compositions containing homogeneous MAO cocatalyst or using MAO cocatalyst supported on inorganic supports.

[0006] The applicant has demonstrated that, surprisingly, a composition comprising a chromium - based or titanium - based metal precursor, solid MAO as a support, and an additive in the form of an aluminum - based compound gives rise to a catalytic composition that is active and selective in ethylene oligomerization (ethylene trimerization and tetramerization to 1 - hexene and 1 - octene respectively), while allowing control of the morphology of polymer by - products, thus solving the problem of reactor fouling.

[0007] Solid MAO is a polyaluminoxane with a degree of polymerization greater than that of traditional MAO. It is generally insoluble in traditional organic solvents and can be directly used as a support for forming catalysts. This solid MAO is specifically sold by Tosoh Finechem Corporation and is described, for example, in the literature US20110282017, US2015057418, or US2018355077. Summary of the Invention

[0009] The present invention relates to a catalytic composition for the selective oligomerization of ethylene, and more particularly for the trimerization and / or tetramerization of ethylene into 1-hexene and / or 1-octene respectively, which comprises:

[0010] - at least one chromium-based or titanium-based metal precursor;

[0011] - at least one support in the form of a solid methylaluminoxane (MAO);

[0012] - at least one additive in the form of an aluminum-based compound.

[0013] One advantage of the catalytic composition according to the present invention is that it particularly controls the morphology of the polymer by-products formed, thus allowing them to be easily removed from the reactor while maintaining a high level of yield and selectivity of 1-hexene and / or 1-octene. DETAILED DESCRIPTION OF THE INVENTION

[0015] According to the present invention, the expressions “… to …” and “… through …” are equivalent and mean that the limits of the interval are included within the described range of values. If this is not the case and if the limits are not included in the said range, the present invention will introduce such information.

[0016] For the purposes of the present invention, the various parameter ranges of a given step, such as a pressure range and a temperature range, can be used alone or in combination. For example, for the purposes of the present invention, a series of preferred pressure values can be combined with a series of more preferred temperature values.

[0017] Hereinafter, specific embodiments of the present invention will be described. They can be implemented alone or in combination, without being limited by the combination as long as it is technically feasible.

[0018] Metal Precursor

[0019] A “metal precursor” is as follows: a compound containing a metal center and at least one ligand, which can be charged or neutral, organic or inorganic, and has the ability to interact with the support through ionic interaction to form a catalyst.

[0020] Cr-based precursor

[0021] The composition of the present invention comprises at least one chromium-based metal precursor, preferably selected from chromium (II) or chromium (III) salts.

[0022] Preferably, the chromium metal precursor may comprise one or more identical or different anions selected from halide ions, carboxylate, acetylacetonate, and alkoxy and aryloxy anions. The chromium compound may be a chromium(II) or chromium(III) salt, but may also be a salt with different oxidation states, which may comprise one or more identical or different anions, such as halide ions, carboxylate, acetylacetonate or alkoxy or aryloxy anions.

[0023] Preferably, the halogen anion is selected from chloride, bromide, fluoride or iodide ions.

[0024] Preferably, the carboxylate anion is selected from carboxylates having a C 3 -C 20 、preferably C 3 -C 15 、preferably C 4 -C 12 、preferably C 5 -C 10 linear or branched alkyl chain, preferably the alkyl chain is unsubstituted or substituted by one or more fluorine, chlorine or bromine atoms.

[0025] Preferably, the alkoxy anion is selected from alkoxies having a C 1 -C 20 、preferably C 2 -C 15 、preferably C 3 -C 12 、preferably C 4 -C 10 linear, branched, cyclic or acyclic alkyl chain, preferably the alkyl chain is unsubstituted or substituted by one or more fluorine, chlorine or bromine atoms.

[0026] Preferably, the aryloxy anion is selected from aryloxies having a C 5 -C 30 、preferably C 5 -C 20 、preferably C 6 -C 15 、preferably C 6 -C 12 aryl, preferably the aryl is unsubstituted or substituted by one or more fluorine, chlorine or bromine atoms.

[0027] In one embodiment, the chromium compound used in the present invention is a chromium(III) compound, although chromium(I) or chromium(II) compounds may also be suitable. Non-limiting examples include chromium(III) acetylacetonate, chromium(III) trifluoroacetylacetonate, chromium(III) hexafluoroacetylacetonate, chromium(III) acetate, chromium(III) 2-ethylhexanoate, chromium(III) heptanoate, chromium(III) naphthenate, chromium(III) chloride, and chromium(III) bromide, used alone or as a mixture, pure or diluted. Preferred Cr precursor derivatives are chromium(III) acetylacetonate, chromium(III) 2-ethylhexanoate, and chromium(III) heptanoate.

[0028] In one embodiment, when the composition according to the present invention contains at least one chromium-based metal precursor, the composition may further contain at least one heteroatom ligand.

[0029] The heteroatom ligand advantageously conforms to the general formula (i):

[0030] ()

[0031] where

[0032] R 1 、R 2 、R 3 、R 4 and R 5 are the same or different from each other and are combined or not combined with each other, and are selected from cyclic or acyclic alkyl groups having 1 to 15 carbon atoms (C 1 -C 15 ) with or without one or more heteroelements, and substituted or unsubstituted aryl groups having 4 to 15 carbon atoms (C 4 -C 15 ) with or without one or more heteroelements.

[0033] The heteroelements are preferably selected from iodine, bromine, chlorine, fluorine, nitrogen, sulfur, and / or oxygen.

[0034] R 1 、R 2 、R 3 、R 4 and R 5 are preferably the same or different and are selected from C 1 -C 10 alkyl groups, C 3 -C 10 cycloalkyl groups, and C 5 -C 15 aryl groups.

[0035] R 1 、R 2 、R 3 、R4 and R 5 are preferably the same or different and are selected from C 1 -C 6 alkyl, C 3 -C 6 cycloalkyl and C 5 -C 12 aryl.

[0036] Preferably, the groups R 1 , R 2 , R 3 , R 4 and R 5 are the same as or different from one another, are bonded to each other or not, and are selected from substituted or unsubstituted methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl and adamantyl; and / or phenyl, o-tolyl, m-tolyl, p-tolyl, mesityl, 3,5-dimethylphenyl, 4-n-butylphenyl, 2-methoxyphenyl, 3-methoxyphenyl, 4-methoxyphenyl, 2-isopropylphenyl, 4-methoxy-3,5-dimethylphenyl, 3,5-di-tert-butyl-4-methoxyphenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 4-trifluoromethylphenyl, 3,5-bis(trifluoromethyl)phenyl, benzyl, naphthyl, binaphthyl, pyridyl, furyl and thienyl.

[0037] The heteroatom ligand is preferably selected from: (phenyl) 2 PN(methyl)P(phenyl) 2 , (phenyl) 2 PN(isopropyl)P(phenyl) 2 , (phenyl) 2 PN(phenyl)P(phenyl) 2 , (2-methoxyphenyl) 2 PN(isopropyl)P(phenyl) 2 , (2-methoxyphenyl) 2 PN(isopropyl)P(2-methoxyphenyl) 2 , (4-methoxyphenyl) 2 PN(isopropyl)P(4-methoxyphenyl) 2 , (2-fluorophenyl) 2 PN(isopropyl)P(2-fluorophenyl) 2 , (2-fluorophenyl)(phenyl)PN(isopropyl)P(2-fluorophenyl) 2 , (2-fluorophenyl)(phenyl)PN(isopropyl)P(2-fluorophenyl)(phenyl), (2-fluorophenyl)(phenyl)PN(isopropyl)P(phenyl) 2 .

[0038] The heteroatom ligand is very preferably selected from (phenyl) 2 PN(isopropyl)P(phenyl) 2 and (2-fluorophenyl) 2 PN(isopropyl)P(2-fluorophenyl) 2 .

[0039] Preferably, the molar ratio of the heteroatom ligand to the chromium-based metal precursor (expressed as HL / Cr) is from 0.5 to 10, preferably from 0.8 to 6, more preferably from 1.0 to 4.0, and very preferably from 1.2 to 2.0.

[0040] Ti-based precursor

[0041] The composition according to the invention comprises at least one titanium-based metal precursor, preferably selected from Ti(IV) coordination complexes conforming to formula (ii):

[0042]

[0043] wherein

[0044] R 6 、R 7 、R 8 、R 9 、R 10 、R 11 、R 12 、R 13 、R 14 、R 15 、R 16 、R 17 and R 18 are the same as or different from each other and are bonded or not bonded to each other, and are selected from hydride ion groups, fluoride ion groups, chloride ion groups, bromide ion groups, cyclic or acyclic alkyl groups having 1 to 15 carbon atoms (C 1 -C 15 ) with or without one or more heteroelements, and / or one or more substituted or unsubstituted aryl groups having 4 to 15 carbon atoms (C 4 -C 15 ) with or without one or more heteroelements, or substituted or unsubstituted aryl groups having 4 to 15 carbon atoms (C 4 -C 15 ) with or without one or more heteroelements.

[0045] R 7 、R 9 、R 10 、R 11 、R 12 、R 13 、R 14 、R15 , R 16 and R 17 are preferably the same and are selected from hydride, methyl, ethyl or fluoride ion. R 7 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 and R 17 are very preferably the same and are selected from hydride ion.

[0046] Preferably, R 18 is selected from C 1 -C 6 alkyl, C 3 -C 6 cycloalkyl or substituted or unsubstituted C 4 -C 15 aryl which contains or does not contain one or more hetero elements. Preferably, R 18 is selected from substituted or unsubstituted methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl and adamantyl; or, in one embodiment, phenyl, o-tolyl, m-tolyl, p-tolyl, mesityl, 3,5-dimethylphenyl, 4-n-butylphenyl, 2-methoxyphenyl, 3-methoxyphenyl, 4-methoxyphenyl, 2-isopropylphenyl, 4-methoxy-3,5-dimethylphenyl, 3,5-di-tert-butyl-4-methoxyphenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 4-trifluoromethylphenyl, 3,5-bis(trifluoromethyl)phenyl, benzyl, naphthyl, binaphthyl, pyridyl, furyl and thienyl. Very preferably, R 18 is selected from methyl.

[0047] Preferably, R 6 and R 8 are the same or different and are selected from C 1 -C 10 alkyl, C 3 -C 10 cycloalkyl or substituted or unsubstituted C 4 -C 15 aryl which contains or does not contain one or more hetero elements. Preferably, R 6 and R 8 are the same or different and are selected from C 1 -C 6 alkyl, C 6 -C 10A cycloalkyl group or a substituted or unsubstituted C containing or not containing one or more heteroelements 4 -C 6 aryl group. More preferably, R 6 and R 8 are the same or different from each other, combined or not combined with each other, and are selected from substituted or unsubstituted methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, adamantyl, phenyl, o-tolyl, m-tolyl, p-tolyl, mesityl, 3,5-dimethylphenyl, 4-n-butylphenyl, 2-methoxyphenyl, 3-methoxyphenyl, 4-methoxyphenyl, 2-isopropylphenyl, 4-methoxy-3,5-dimethylphenyl, 3,5-di-tert-butyl-4-methoxyphenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 4-trifluoromethylphenyl, 3,5-bis(trifluoromethyl)phenyl, benzyl, naphthyl, binaphthyl, pyridyl, furyl and thienyl. Most preferably, R 6 and R 8 are the same or different from each other, combined or not combined with each other, and are selected from tert-butyl or adamantyl.

[0048] The three groups X 1 are the same or different from each other and they are selected from anionic groups. Non-limiting examples include fluoride ion, chloride ion, bromide ion, iodide ion, hydroxide, methyl, n-ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, methoxy, ethoxy, propoxy, formate, acetate, propionate or carbonate. More preferably, the groups X 1 are the same and they are selected from chloride ion, bromide ion or iodide ion groups. Most preferably, the groups X 1 are chloride ions.

[0049] The groups X 2 are defined by coordinating heteroatoms. The heteroelements are selected from nitrogen, phosphorus, sulfur or oxygen. More preferably, the groups X 2 are selected from oxygen.

[0050] The carrier in the form of solid MAO

[0051] When using the catalytic composition, the carrier allows the formation of a catalyst through the ionic interaction between the metal precursor and the carrier; such a catalyst structure can be called a floating cation. The catalytic reaction occurs on the surface or in the pores of the formed catalyst.

[0052] The catalytic composition according to the present invention comprises at least one carrier in the form of solid methylaluminoxane (MAO).

[0053] A description of solid MAO and its manufacturing method that can be used for the catalytic composition according to the present invention can be found in the documents US20110282017, US2015057418 or US2018355077 under the name of Tosoh Finechem Corporation, or in the document US6518445 under the name of Albemarle Corporation.

[0054] The terms "solid MAO" or "solid methylaluminoxane" will be used equivalently. The definition of solid MAO is a special compound that exists in the form of a solid suspension in hydrocarbon (aromatic or aliphatic) solvents such as toluene, cyclohexane, pentane, heptane, etc. at ambient temperature (30 °C or below). Any solid MAO that is insoluble in hydrocarbon solvents can act as a carrier according to the present invention.

[0055] Solid MAO advantageously contains a polymer chain (PMAO) formed by Al, O atoms and methyl groups (-Me or -CH 3 ), defined by the following formula (iii):

[0056] (iii) -[(Me)AlO]n-

[0057] where n can advantageously take values between 1 and 60, preferably between 10 and 50. Solid MAO basically contains PMAO chains according to formula (iii), although its structure may also contain related trimethylaluminum, either free or interacting with the PMAO chains. PMAO can have a linear, cyclic or branched structure, provided that the polymer chain satisfies formula (iii).

[0058] The solid MAO used in the present invention may contain PMAO with a linear and / or branched structure, but may also contain cyclic fragments and residual molecules of the solvent interacting with TMA.

[0059] The aluminum mass content of solid MAO is advantageously 36% to 52%. This ensures that solid MAO has good properties such as optimal size and anti-cracking during various synthesis steps.

[0060] Solid MAO is preferably defined as having an aluminum content of 38% to 43% by mass. Solid MAO more preferably has an aluminum content of 40% to 42% by mass. Solid MAO very preferably has an aluminum content of 40.5% to 41.5% by mass.

[0061] Solid MAO is advantageously in the form of particles, defined as having an average diameter less than or equal to 200 μm, preferably less than or equal to 150 μm, more preferably less than or equal to 100 μm, and very preferably less than or equal to 50 μm.

[0062] In a preferred embodiment, the solid MAO is in particulate form and is defined as having an average diameter of from 1 to 50 μm, preferably from 5 to 40 μm, preferably from 10 to 30 μm, preferably from 15 to 25 μm.

[0063] Advantageously, the molar ratio of the solid MAO to the chromium-based or titanium-based metal precursor (expressed as Al / Cr or Al / Ti) is from 1 to 10,000, preferably from 25 to 5,000, more preferably from 50 to 2,500, and very preferably from 100 to 1,500. The molar ratio of the solid MAO to the chromium-based or titanium-based metal precursor is calculated as the ratio of the number of moles of Al contained in the solid to the number of moles of metal contained in the precursor.

[0064] By virtue of these properties of the solid MAO, advantageous properties of the polymer by-products formed during the oligomerization process can be obtained, such as the apparent density of the polymer molecules, thereby preventing, for example, fouling of the reactor.

[0065] Additive in the form of an aluminum-based compound

[0066] The composition according to the invention comprises at least one additive in the form of an aluminum-based compound.

[0067] In one embodiment, the aluminum-based compound is a compound of the formula Al(R 19 ) 3 , where R 19 is independently selected from C 1 -C 12 alkyl, C 1 -C 12 alkoxy and halogen. Preferably, R 19 is independently selected from C 1 -C 10 alkyl, C 1 -C 10 alkoxy, preferably C 1 -C 6 alkyl, C 1 -C 6 alkoxy and a chlorine or bromine atom. Preferably, R 19 is an alkyl and / or alkoxy selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, pentyl, hexyl, heptyl and octyl and the corresponding alkoxies. Preferably, R 19 is an alkyl and / or alkoxy selected from ethyl, propyl, iso-propyl / isopropyl, n-butyl and tert-butyl and the corresponding alkoxies.

[0068] More preferably, the aluminum-based compound is selected from trimethylaluminum (TMA), triethylaluminum (TEA), triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-tert-butylaluminum, trihexylaluminum, trioctylaluminum, diethylethoxyaluminum and dimethylethoxyaluminum, methyldichloridealuminum, ethyldichloridealuminum, dimethylchloridealuminum, diethylchloridealuminum, ethyl sesquichloridealuminum, and aluminoxanes such as methylaluminoxane (MAO), modified methylaluminoxane (MMAO), or ethylaluminoxane (EAO), either alone or as a mixture.

[0069] More preferably, the aluminum-based compound is selected from trimethylaluminum (TMA), triethylaluminum (TEA), triisobutylaluminum, methylaluminoxane (MAO), and modified methylaluminoxane (MMAO), either alone or as a mixture.

[0070] Very preferably, the aluminum-based compound is trimethylaluminum (TMA), triethylaluminum (TEA), and triisobutylaluminum, either alone or as a mixture.

[0071] Preferably, the molar ratio of the aluminum-based compound to the chromium-based or titanium-based metal precursor (expressed as Al / Cr or Al / Ti) is from 1 to 1500, preferably from 10 to 1000, more preferably from 20 to 500, and very preferably from 50 to 300.

[0072] Without wishing to be bound by any particular theory, the presence of the additive in the form of an aluminum-based compound is crucial for activating the metal precursor and generating the active species involved in the catalytic reaction. The amount of relevant TMA in solid MAO is significantly lower than that in solution MAO. In this case, the presence of the additive serves to alkylate the metal complex and initiate the catalytic reaction.

[0073] Optional solvent

[0074] The catalytic composition according to the invention may further comprise a solvent. Solvents selected from organic solvents and more particularly from saturated, unsaturated, cyclic or acyclic hydrocarbons may be used.

[0075] (One or more) solvents are advantageously selected from halogenated solvents and saturated or unsaturated, cyclic or acyclic hydrocarbons containing from 1 to 20 carbon atoms, preferably from 1 to 15 carbon atoms, and preferably from 4 to 15 carbon atoms.

[0076] Preferably, the solvent is selected from isobutane, pentane, hexane, heptane, cyclohexane, methylcyclohexane, butane or isobutane, dichloromethane, toluene, xylene, dichloroethane, chlorobenzene, dichlorobenzene, pure or as a mixture. More preferably, the solvent is selected from hexane, heptane, cyclohexane, methylcyclohexane, toluene, and xylene.

[0077] In a preferred embodiment, the solvent may advantageously be selected from the products of the oligomerization reaction.

[0078] Formulation of the Catalytic Composition

[0079] The catalytic composition according to the present invention can be formulated by preparing a mixture comprising a chromium-based or titanium-based metal precursor, an optional heteroatom ligand, a solid MAO used as a support, and an aluminum-based compound used as an additive.

[0080] Preferably, for the tetramerization of ethylene, the catalytic composition is formulated by preparing a mixture comprising, on the one hand, a chromium-based metal precursor, an optional heteroatom ligand, and a solid MAO, and, on the other hand, an (one or more) aluminum-based compound.

[0081] Preferably, for the trimerization of ethylene, the catalytic composition is formulated by preparing a pre-catalytic mixture comprising, on the one hand, a Ti-based metal precursor and a solid MAO, and, on the other hand, an (one or more) aluminum-based compound.

[0082] More preferably, each component or mixture of components of the catalytic composition can be used in a solvent as defined above. In the case where the solvent is an unsaturated hydrocarbon, it can advantageously be selected from the products of the oligomerization reaction.

[0083] Use of the Composition in a Process for the Oligomerization of Olefins

[0084] Another subject of the present invention relates to a process for the oligomerization, preferably the selective trimerization and / or tetramerization of ethylene to 1-hexene and / or 1-octene, respectively, using the catalytic composition according to the present invention.

[0085] The feedstock used in the oligomerization process is preferably gaseous ethylene.

[0086] Advantageously, the concentration of the metal precursor (Cr or Ti) used in the oligomerization process is from 0.01 to 10000 μmol / L, more preferably from 0.1 to 1000 μmol / L, and very preferably from 1 to 100 μmol / L.

[0087] The process can advantageously be carried out in the presence of the above-mentioned solvent.

[0088] Advantageously, the oligomerization process is carried out at a total pressure of from 0.1 to 20.0 MPa, preferably from 0.1 to 15.0 MPa, and more preferably from 0.5 to 8.0 MPa, and at a temperature of from 15 to 200 °C, preferably from 20 °C to 100 °C, and very preferably from 25 °C to 80 °C.

[0089] The heat generated by the reaction can be removed by any means known to those skilled in the art.

[0090] Advantageously, the process for oligomerization and more particularly for the trimerization and / or tetramerization of ethylene into 1 - hexene and / or 1 - octene can be carried out continuously. In one case, the components of the catalytic composition according to the invention are injected into a reactor stirred by conventional mechanical means or by external recirculation, in which ethylene reacts, preferably with temperature control. In another case, a solution comprising a mixture consisting on the one hand of a chromium - based or titanium - based metal precursor supported on solid MAO and on the other hand of one or more aluminum - based compounds is injected separately into a reactor stirred by conventional mechanical means or by external recirculation, in which ethylene reacts, preferably with temperature control.

[0091] The catalytic composition can be neutralized downstream of the reactor by any method known to those skilled in the art.

[0092] The following examples illustrate the invention without limiting its scope. Description of the Drawings

[0093] Figure 1 Image of the stirrer blades of a reactor after an ethylene oligomerization process using a homogeneous catalytic composition comprising MAO as described in Example 1 or 7. "Sticky" polymer by - products are observed on the stirrer, which are difficult to remove and can cause fouling of the reactor.

[0094] Figure 2 Represents Figure 1 A scanning electron microscope image of the morphology of the polymer by - products in. "Filamentous" structures are observed, which are characteristic of polymers with uncontrolled morphology.

[0095] Figure 3 Image of the stirrer blades of a reactor after an ethylene oligomerization process using a catalytic composition comprising solid MAO as described in Examples 3, 4, 5, 6, 9 or 10. Granular polymer by - products are observed on the stirrer, which are easy to remove and do not cause fouling of the reactor.

[0096] Figure 4 Represents Figure 3 A scanning electron microscope image of the morphology of the polymer by - products in. "Granular" structures are observed, which are characteristic of polymers with controlled morphology. Examples

[0097] Example 1 (Comparative Example): A method for ethylene trimerization using a homogeneous MAO solution in toluene as a cocatalyst (500 equivalents of Al relative to Ti) A method for ethylene trimerization

[0098] In a glove box, 11.4 mg (20.0 mmol) of the aryloxyimino titanium(IV) chloride complex as described in structure (iv) below was weighed into a Schlenk flask, and then 10 ml of anhydrous toluene (solution concentration: 2.0 mM) was added under argon.

[0099] (iv)

[0100] In a 250 ml reactor, the internal temperature of the reactor was pre-adjusted to 25 °C and the ethylene pressure was 0.5 bar, and 91 ml of cyclohexane was added. Subsequently, while stirring at 1500 rpm for one minute, 5 bar of gaseous ethylene was introduced to saturate the solvent with ethylene. Again, the pressure of the reactor was reduced to 0.5 bar and stirring was stopped. Subsequently, 5 ml of molecular sieve-dried nonane (3.6 g, internal standard), 2.0 ml of a 2.0 mM titanium complex solution (4 μmol), and 1.25 ml of an MAO solution (solution % Al: 4.90%, density: 0.880 g / ml), or approximately 54 mg of Al (2.0 mmol) were introduced. Then the ethylene inlet valve (30 bar pressure) was opened, stirring was started, and the heating set point of the reactor was raised to 28 °C.

[0101] At the end of the test, the ethylene supply was cut off, the mixture was cooled to 20 °C, and then the gas phase was vented to the exhaust. Then the reactor was opened. The liquid was transferred to a bottle containing 1.00 ml of 10% H 2 SO 4 solution. An organic phase sample was taken out and filtered for analysis. The results are shown in Table 1.

[0102] Example 2 (Comparative Example): A method for ethylene trimerization using a solid MAO cocatalyst (1000 equivalents of Al relative to Ti) without using an additive A method for ethylene trimerization

[0103] Under argon, 2.70 ml of solid MAO provided by Tosoh (11.24 wt%, Al mass content in MAO: 41.2%, density: 0.868 g / ml, average particle size: 20 μm), or approximately 109 mg of Al (4.0 mmol) was introduced into a Schlenk flask. 2.00 ml of a 2.0 mM titanium(IV) complex solution (4 μmol) was added to the Schlenk flask containing the solid MAO. An orange gel formed at the bottom of the Schlenk flask. The mixture was heated at 50 °C for 1 hour and manually stirred every 15 minutes.

[0104] The heating set point of the reactor thermostat was adjusted to 25 °C. Subsequently, 91.0 ml of cyclohexane was introduced into the reactor, which had been pre-conditioned by introducing an ethylene atmosphere of 0.5 bar. Subsequently, after stirring for one minute at 1500 rpm, after introducing 5 bar of gaseous ethylene, the solvent was saturated with ethylene. The pressure of the reactor was reduced to 0.5 bar and stirring was stopped. 5 ml of molecular sieve-dried nonane (3.6 g) was introduced. Finally, all of the previously prepared oligomerization catalyst, which was suspended in toluene, was introduced. The ethylene inlet valve was opened (pressure 30 bar), stirring was started, and then the heating set point of the reactor was raised to 28 °C.

[0105] At the end of the test, the ethylene supply was cut off, the mixture was cooled to 20 °C, and then the gas phase was vented to the exhaust. Then the reactor was opened. The liquid was transferred to a bottle containing 1.00 ml of 10% H 2 SO 4 solution. An organic phase sample was taken and filtered for analysis. The results are shown in Table 1.

[0106] Example 3 (According to the present invention): A method for ethylene trimerization using a solid MAO cocatalyst (1000 equivalents of Al relative to Ti) and TEA as an additive A method for ethylene trimerization

[0107] This test was carried out under conditions similar to those of Example 2, but a solution of TEA (0.2 mmol) in 1.00 ml of 0.20 M cyclohexane was introduced into the reactor. The TEA solution was introduced after the nonane. The results are shown in Table 1.

[0108] Example 4 (According to the present invention): A method for ethylene trimerization using a solid MAO cocatalyst (521 equivalents of Al relative to Ti) and TEA as an additive A method for ethylene trimerization

[0109] This test was carried out under conditions similar to those of Example 3, but 1.40 ml of Tosoh solid MAO (11.24 wt%, Al mass content of MAO: 41.2%, density: 0.868 g / ml, average particle size: 20 μm), or approximately 56 mg of Al (2.1 mmol), was used. The results are shown in Table 1.

[0110] Example 5 (According to the present invention): A method for ethylene trimerization using a solid MAO cocatalyst (1000 equivalents of Al relative to Ti) and TMA as an additive A method for ethylene trimerization

[0111] This test was carried out under conditions similar to those of Example 3, but a solution of 1.00 ml of 0.20 M TMA (0.2 mmol) was introduced into the reactor. The TMA solution was introduced after the nonane. The results are shown in Table 1.

[0112] Example 6 (According to the present invention): A method for ethylene trimerization using a solid MAO cocatalyst (521 equivalents of Al relative to Ti) and TMA as an additive A method for ethylene trimerization

[0113] This test was carried out under conditions similar to those of Example 4, but 1.00 ml of a 0.20 M TMA solution (0.2 mmol) was introduced into the reactor. The TMA solution was introduced after the nonane.

[0114] The results of Examples 1 to 6 are shown in Table 1.

[0115] Table 1.

[0116]

[0117] * indicates the percentage of 1 - hexene isomers in the molecule (C6) with six carbon atoms

[0118] Example 7 (Comparative Example) - A method for ethylene tetramerization in solution using a conventional solution of homogeneous MMAO-3A in cyclohexane as a cocatalyst (1340 equivalents of Al relative to Cr) A method for ethylene tetramerization in solution

[0119] The ethylene tetramerization test was carried out using C 2 containing 0.5 mol% H 2 H 4 .

[0120] In a 500 ml reactor, the internal temperature of the reactor was pre - adjusted to 25 °C and the ethylene pressure was 0.5 bar. 188 ml of cyclohexane was introduced. Subsequently, while stirring at 1500 rpm for one minute, after introducing 5 bar of the gas, the solvent was saturated with ethylene. Again, the pressure of the reactor was evacuated to 0.5 bar and the stirring was stopped. 4.0 ml of MMAO - 3A solution (solution % Al: 0.6%, density: 0.723 g / ml), or approximately 18 mg of Al (0.67 mmol) was introduced. At the same time, under argon, 4.0 ml of a 0.125 mM complex Cr(acac) 3 (0.5 μmol) solution and 4.0 ml of a 0.15 mM ligand N,N - bis(bis(2 - fluorophenyl)phosphino)isopropylamine (0.6 μmol) solution were added to a Schlenk flask. Then 8 ml of the Cr / ligand solution was injected into the reactor. The ethylene inlet valve (pressure of 40 bar) was opened, stirring was started, and then the heating set - point of the reactor was raised to 45 °C.

[0121] After reacting for 1 hour, the ethylene supply was cut off, the mixture was cooled to 20 °C, and then the gas phase was slowly vented to the exhaust. Then the reactor was opened. The liquid was transferred to a bottle containing 1.00 ml of 10% H 2 SO 4 solution. An organic phase sample was taken out and filtered for analysis.

[0122] Example 8 (Comparative Example) - A method for ethylene tetramerization in solution using solid MAO as a cocatalyst (1360 equivalents of Al relative to Cr) A method for ethylene tetramerization in solution

[0123] The solid MAO sold by Tosoh is provided in the form of a suspension in toluene (11.24 wt%, Al mass content of MAO: 41.2%, density: 0.868 g / ml, average particle size: 20 μm). To prevent the presence of toluene that may poison the catalyst, a suspension of solid MAO in cyclohexane was prepared. 10 ml of solid MAO (402 mg Al, 14.9 mmol) was charged into a Schlenk flask. The suspension was filtered and the powder was washed with cyclohexane (2 × 5 ml). Finally, 119 ml of cyclohexane was added to obtain a 0.125 M solid MAO suspension.

[0124] In a 500 ml reactor, the internal temperature of the reactor was pre-adjusted to 25 °C and the ethylene pressure was 0.5 bar. 188 ml of cyclohexane was introduced. Subsequently, after introducing 5 bar of the gas while stirring at 1500 rpm for one minute, the solvent was saturated with ethylene. Again, the pressure of the reactor was evacuated to 0.5 bar and stirring was stopped. 5.4 ml of a suspension of solid MAO in cyclohexane, or approximately 18 mg of Al (0.68 mmol), was added. At the same time, under argon, 4.0 ml of a 0.125 mM complex Cr(acac) 3 (0.5 μmol) solution and 4.0 ml of a 0.15 mM ligand N,N-bis(bis(2-fluorophenyl)phosphino)isopropylamine (0.6 μmol) solution were added to the Schlenk flask. Then 8 ml of the Cr / ligand solution was injected into the reactor. The ethylene inlet valve was opened (pressure of 40 bar), stirring was started, and then the heating set point of the reactor was raised to 45 °C.

[0125] After reacting for 1 hour, the ethylene supply was cut off, the mixture was cooled to 20 °C, and then the gas phase was slowly vented to the exhaust port. Then the reactor was opened. The liquid was transferred to a bottle containing 1.00 ml of 10% H 2 SO 4 solution. An organic phase sample was taken out and filtered for analysis.

[0126] Example 9 (According to the present invention) - A method for ethylene tetramerization in solution using solid MAO as a cocatalyst (1360 equivalents of Al relative to Cr) and TEA A method for ethylene tetramerization in solution

[0127] The ethylene tetramerization test was carried out using C 2 containing 0.5 mol% H 2 H 4 .

[0128] This test was carried out under conditions similar to those of Example 8, but 0.4 ml of a 0.125 M TEA solution (0.05 mmol) was introduced into the reactor as an additive. The TEA solution was introduced after the solid MAO.

[0129] Example 10 (According to the present invention) - A method for ethylene tetramerization in solution using solid MAO as a cocatalyst (1360 equivalents of Al relative to Cr) and TEA A method for ethylene tetramerization in solution

[0130] The ethylene tetramerization test was carried out using C 2 containing 0.5 mol% H 2 H 4 .

[0131] This test was carried out under conditions similar to those of Example 8, but 2.00 ml of a 0.125 M TEA solution (0.25 mmol) was introduced into the reactor as an additive. The TEA solution was introduced after the solid MAO.

[0132] The results of Examples 7 to 10 are shown in Table 2.

[0133] Table 2.

[0134]

[0135] * represents the percentage of 1-octene isomers in the molecule (C8) with 8 carbon atoms

[0136] These examples demonstrate that the catalytic composition according to the invention acts due to the presence of an additive in the form of an aluminum-based compound and is capable of achieving a high selectivity for the selected molecule (currently 1-hexene or 1-octene), which selectivity is close to that of the prior art catalytic compositions based on homogeneous MAO, and is capable of obtaining polymer by-products (currently PE) with a controlled morphology, which do not foul the oligomerization reactor and can be easily removed from the reactor, unlike the "sticky" filaments of PE.

Claims

1. A catalytic composition for the selective oligomerization of ethylene, more particularly for the trimerization and / or tetramerization of ethylene into 1-hexene and / or 1-octene respectively, which comprises: - at least one chromium-based or titanium-based metal precursor; - at least one support in the form of solid methylaluminoxane (MAO); - at least one additive in the form of an aluminum-based compound.

2. The catalytic composition according to claim 1, wherein the chromium precursor is selected from chromium(II) or chromium(III) salts.

3. The catalytic composition according to claim 1 or 2, further comprising at least one heteroatom ligand.

4. The catalytic composition according to claim 1, wherein the titanium precursor is selected from Ti(IV) coordination complexes conforming to formula (ii): wherein R 6 、R 7 、R 8 、R 9 、R 10 、R 11 、R 12 、R 13 、R 14 、R 15 、R 16 、R 17 and R 18 are the same as or different from one another, and are combined or not combined with one another, and are selected from a hydride ion group, a fluoride ion group, a chloride ion group, a bromide ion group, a cyclic or acyclic alkyl group having 1 to 15 carbon atoms (C 1 -C 15 ) which may or may not contain one or more hetero elements, and / or one or more substituted or unsubstituted aryl groups having 4 to 15 carbon atoms (C 4 -C 15 ) which may or may not contain one or more hetero elements, or substituted or unsubstituted aryl groups having 4 to 15 carbon atoms (C 4 -C 15 ) which may or may not contain one or more hetero elements.

5. The catalytic composition according to any one of the preceding claims, wherein the molar ratio of the solid MAO to the chromium-based or titanium-based metal precursor (expressed as Al / Cr or Al / Ti) is from 1 to 10,000, preferably from 25 to 5,000, more preferably from 50 to 2,500, and very preferably from 100 to 1,500.

6. The catalytic composition according to any one of the preceding claims, wherein the aluminum mass content of the solid MAO is from 36% by mass to 52% by mass.

7. The catalytic composition according to any one of the preceding claims, wherein the solid MAO is in particulate form, defined as having an average diameter of from 1 to 50 μm, preferably from 5 to 40 μm, preferably from 10 to 30 μm, preferably from 15 to 25 μm.

8. The catalytic composition according to any one of the preceding claims, wherein the aluminum-based compound is a compound of the formula Al(R 19 ) 3 , wherein R 19 is independently selected from C 1 -C 12 alkyl, C 1 -C 12 alkoxy and halogen.

9. The catalytic composition according to claim 8, wherein the aluminum-based compound is trimethylaluminum (TMA), triethylaluminum (TEA), and triisobutylaluminum, either alone or as a mixture.

10. The catalytic composition according to any one of the preceding claims, wherein the molar ratio of the aluminum-based compound to the chromium-based or titanium-based metal precursor (expressed as Al / Cr or Al / Ti) is from 1 to 1,500, preferably from 10 to 1,000, more preferably from 20 to 500, and very preferably from 50 to 300.

11. The catalytic composition according to any one of the preceding claims, further comprising a solvent.

12. The catalytic composition according to claim 11, wherein the solvent is advantageously selected from halogenated solvents and saturated or unsaturated, cyclic or acyclic hydrocarbons having from 1 to 20 carbon atoms, preferably from 1 to 15 carbon atoms, and preferably from 4 to 15 carbon atoms.

13. An oligomerization process using the catalytic composition according to any one of the preceding claims, preferably for the selective trimerization and / or tetramerization of ethylene into 1-hexene and / or 1-octene respectively.

14. The oligomerization process according to claim 13, wherein the concentration of the metal precursor supported on the solid MAO is from 0.01 to 10,000 μmol / L, preferably from 0.1 to 1,000 μmol / L, and very preferably from 1 to 100 μmol / L.

15. The oligomerization process according to claim 13 or 14 is carried out at a total pressure of from 0.1 to 20.0 MPa, preferably from 0.1 to 15.0 MPa, and more preferably from 0.5 to 8.0 MPa, and at a temperature of from 15 to 200 °C, preferably from 20 °C to 100 °C, and very preferably from 25 °C to 80 °C.

Images