Metal compound containing nitrogen and phosphine, preparation method thereof, catalyst composition and method for preparing olefin polymer

Abstract

The invention discloses a metal compound containing nitrogen and phosphine, a preparation method of the metal compound, a catalyst composition and a method for preparing an olefin polymer. The metal compound has a structure as shown in a formula (1). The catalyst containing the metal compound containing nitrogen and phosphine provided by the invention has the advantages of high catalytic activity and low catalyst cost, and the metal compound can be used as a catalyst for olefin polymerization for olefin homopolymerization or copolymerization, especially for ethylene homopolymerization and copolymerization of ethylene and alpha olefin.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to nitrogen- and phosphine-containing pre-transition metal compounds and their preparation methods, as well as to catalyst compositions for olefin polymerization, the application of such catalyst compositions in catalytic homopolymerization of ethylene and / or copolymerization of ethylene-α-olefins, and methods for preparing olefin polymers. Background Technology

[0002] Polyolefins are homopolymers and copolymers containing ethylene and α-olefins. Polyolefins play a crucial role in the synthetic resin industry, serving as materials for films, pipes, and wires and cables; they are a widely used and very important class of polymeric materials.

[0003] Advances in olefin polymerization catalyst technology are a direct driving force behind technological progress in the polyolefin industry. From traditional Ziegler-Natta catalysts to single-active-center metallocene catalysts that emerged in the late 1980s, and then to highly active "post-metallocene" and post-transition metal catalysts at the end of the 20th century, the catalytic polymerization of olefins has always been a focus of attention for researchers and manufacturers.

[0004] Traditional Ziegler-Natta catalysts suffer from drawbacks such as low catalytic activity, wide molecular weight distribution, and high residual catalyst content in solution polymerization products. The discovery of Group IV metallocene catalysts has largely solved this problem. Due to their single active center, they allow for the modification of catalyst structure to obtain polymers with desired structures (W. Kaminsky et al., Adv. Organomet. Chem. 1980, 18, 99; H. Brintzinger et al., Angew. Chem. Int. Ed. Engl. 1995, 34, 1143). In the past decade or so, research on metal complexes obtained by replacing cyclopentadiene with transition metals using ligands containing N, O, and P coordination atoms as catalysts for olefin polymerization has also flourished. These catalysts are collectively referred to as "Natta-Natta" catalysts.

[0005] US6762258B2 discloses pyridine complexes containing phosphine and nitrogen-containing tridentate ligands Fe, Co, and Ni. In addition, US6239237B1 discloses post-transition metals Fe, Co, Ni, and Pd containing thiophene bisphosphine imine. Both are used for olefin polymerization. However, the catalytic activity of these two complexes for ethylene polymerization is only high under specific reaction conditions (such as high pressure), which is not conducive to their widespread application as catalysts. Summary of the Invention

[0006] The purpose of this invention is to overcome the problem of harsh operating conditions for existing olefin polymerization catalysts, and to provide nitrogen- and phosphine-containing metal compounds, their preparation methods, catalyst compositions, and methods for preparing olefin polymers. Catalysts containing the nitrogen- and phosphine-containing metal compounds provided by this invention have the advantages of high catalytic activity and low cost. These metal compounds can be used as catalysts for olefin polymerization, particularly for ethylene homopolymerization and copolymerization, to obtain high-density polyethylene and ethylene-α-olefin elastomers under flexible conditions.

[0007] The inventors of this invention discovered that introducing organophosphorus compounds, nitrogen, and highly substituted alkyl groups into catalyst ligands can significantly enhance the activity of the central metal atom. Group IVB metal complexes containing phosphine and nitrogen (monodentate ligands), when used as catalysts for the homopolymerization of ethylene and the copolymerization of ethylene with α-olefins, can produce high-density polyethylene or ethylene-α-olefin elastomers with high activity under a wide range of polymerization conditions. In other words, Group IVB metal complexes containing phosphine and nitrogen (monodentate ligands), when used as catalysts for the homopolymerization of ethylene and the copolymerization of ethylene with α-olefins, exhibit significantly higher catalytic activity than Group VIII metal complexes containing phosphine and nitrogen bidentate or tridentate ligands under various polymerization conditions (even at relatively low reaction pressures).

[0008] To achieve the above objectives, a first aspect of the present invention provides a nitrogen- and phosphine-containing metal compound having the structure shown in formula (1).

[0009]

[0010] In equation (1),

[0011] R 1 R 2 and R 3 Each independently chooses H and C. 1-20 hydrocarbon group, C 1-20 The group consisting of alkoxy groups and halogens;

[0012] R1 and R2 are each independently chosen from H and C. 1-4 hydrocarbon group, C 6-12 aryl and C 1-4 hydrocarbon group substituted C 7-16 A group consisting of aryl groups;

[0013] m is 1, 2, or 3;

[0014] Mt is a Group IVB metallic element;

[0015] Cp* is a cyclopentadienyl group containing an electron-donating substituent;

[0016] X is an atom or group bonded to the Mt element, and X is selected from C. 1-10 It is at least one group in the group consisting of a hydrocarbon group and a halogen; n is an integer and satisfies the Mt bond valence.

[0017] A second aspect of the present invention provides a method for preparing a nitrogen- and phosphine-containing metal compound, the method comprising:

[0018] 1) In the presence of an organic solvent, the compound with the structure shown in formula (11) is reacted with n-butyllithium to obtain a first intermediate;

[0019] 2) The first intermediate is reacted with the compound with the structure shown in formula (12) in a second reaction to obtain the second intermediate;

[0020] 3) The second intermediate is reacted with trimethylazidosilane in a third reaction to obtain a third intermediate having the structure shown in formula (13);

[0021] 4) The third intermediate is reacted with the compound with the structure shown in formula (14) in a fourth reaction to obtain the fourth intermediate with the structure shown in formula (15);

[0022] 5) Combine the fourth intermediate with Cp*MtX (n+1) The fifth reaction is carried out to obtain the fifth intermediate;

[0023] 6) The fifth intermediate is reacted with a Grignard reagent in a sixth reaction to obtain a metal compound having the structure shown in formula (1);

[0024]

[0025]

[0026] Among them, equations (11), (12), (13), (14), and (15) Cp*MtX (n+1) The definition of the substituent in formula (1) is the same as that in the first aspect mentioned above, and X1 in formula (12) is a halogen.

[0027] A third aspect of the present invention provides a nitrogen- and phosphine-containing metal compound prepared by the preparation method described in the second aspect above.

[0028] A fourth aspect of the present invention provides a catalyst composition for olefin polymerization, the catalyst composition comprising a main catalyst and an activator; wherein the main catalyst is a nitrogen- and phosphine-containing metal compound as described in any one of the first and third aspects above; and the activator comprises an aluminum-containing compound and optionally an organoboron compound.

[0029] The fifth aspect of the present invention provides the use of the catalyst composition for olefin polymerization described in the fourth aspect above in catalytic olefin polymerization reactions; particularly in catalytic ethylene homopolymerization and / or ethylene-α-olefin copolymerization reactions.

[0030] The sixth aspect of the present invention provides a method for preparing an olefin polymer, the method comprising: in the presence of a solvent, reacting an olefin monomer with the catalyst composition for olefin polymerization described in the fourth aspect above to obtain an olefin polymer.

[0031] The beneficial technical effects achieved by the present invention through the above technical solution are as follows:

[0032] (1) Catalysts containing the aforementioned phosphine and nitrogen (monodentate ligand) metal compounds provided by the present invention have the advantages of high catalytic activity and low catalyst cost, and exhibit excellent catalytic activity under a wide range of polymerization reaction conditions.

[0033] (2) The metal compounds of the present invention can be used as catalysts for olefin polymerization, for olefin homopolymerization or copolymerization, especially for ethylene homopolymerization and ethylene-α-olefin copolymerization, in order to obtain high-density polyethylene and ethylene-α-olefin elastomers under flexible conditions. Detailed Implementation

[0034] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0035] The first aspect of the present invention provides a nitrogen- and phosphine-containing metal compound having the structure shown in formula (1).

[0036]

[0037] In equation (1),

[0038] R 1 R 2 and R 3 Each independently chooses H and C. 1-20 hydrocarbon group, C 1-20 The group consisting of alkoxy groups and halogens;

[0039] R1 and R2 are each independently chosen from H and C. 1-4 hydrocarbon group, C 6-12 aryl and C 1-4 hydrocarbon group substituted C 7-16A group consisting of aryl groups;

[0040] m is 1, 2, or 3;

[0041] Mt is a Group IVB metallic element;

[0042] Cp* is a cyclopentadienyl group containing an electron-donating substituent;

[0043] X is an atom or group bonded to the Mt element, and X is selected from C. 1-10 It is at least one group in the group consisting of a hydrocarbon group and a halogen; n is an integer and satisfies the Mt bond valence.

[0044] In this invention, Cp* is pentamethylcyclopentadienyl.

[0045] In this invention, the halogens include fluorine, chlorine, bromine, and iodine.

[0046] In this invention, R 1 R 2 and R 3 They can be the same or different, but R is preferred. 2 and R 3 same.

[0047] In this invention, the n X's can be the same or different.

[0048] In this invention, C 1-20 The hydrocarbon group refers to a hydrocarbon group with a total number of carbon atoms of 1-20, such as C1, C2, C3, C4, C5, C6, C7, C8, C9, ...1, C1, C1, C1, C 10 C 11 C 12 C 13 C 14 C 15 C 16 C 17 C 18 C 19 Or C 20 Hydrocarbon groups. For example, C 1-20 The hydrocarbon group can be C 1-20 alkyl or C 2-20 The alkenyl group.

[0049] In this invention, C 1-20 The alkoxy group refers to an alkoxy group with a total number of carbon atoms of 1-20, such as C1, C2, C3, C4, C5, C6, C7, C8, C9, ...1, C1, C1, 10 C 11 C 12 C 13 C 14 C 15 C 16C 17 C 18 C 19 Or C 20 alkoxy groups.

[0050] In this invention, C 1-4 The hydrocarbon group refers to a hydrocarbon group with a total number of carbon atoms of 1-4, such as a C1, C2, C3, or C4 hydrocarbon group. For example, it can be a C1, C2, C3, or C4 hydrocarbon group. 1-4 alkyl or C 2-4 The alkenyl group.

[0051] In this invention, C 6-12 The aryl group refers to an aryl group with a total number of carbon atoms of 6-12, such as phenyl, naphthyl, or biphenyl.

[0052] In this invention, C 1-4 C with hydrocarbon substitution 7-16 An aryl group refers to an aryl group with a total number of 7-16 carbon atoms, and at least one H atom on the aryl group is bonded to a carbon atom. 1-4 Hydrocarbon group substitution, for example, can be a hydrocarbon group composed of C 1-4 The alkyl group is substituted with phenyl, naphthyl, biphenyl, anthracene, or phenanthrene. For example, it can be composed of C 1-4 alkyl and / or C 2-4 alkenyl-substituted C 7-16 Aryl groups.

[0053] In this invention, the Group IVB metal element is Ti, Zr, or Hf.

[0054] In some embodiments of the present invention, in formula (1),

[0055] R 1 R 2 and R 3 Each independently chooses H and C. 1-16 hydrocarbon group, C 1-16 The group consisting of alkoxy groups and halogens;

[0056] R1 and R2 are each independently chosen from H and C. 1-4 hydrocarbon group, C 6-10 aryl and C 1-4 hydrocarbon group substituted C 7-14 A group consisting of aryl groups;

[0057] Mt can be Ti, Zr, or Hf;

[0058] X chooses freely C 1-8 It consists of at least one group from the group consisting of hydrocarbon groups, fluorine, chlorine, bromine and iodine.

[0059] For example, all n X's are halogens; or all n X's are carbon. 1-8Hydrocarbon group; or one of the X is C 1-8 The hydrocarbon group and the remaining (n-1) X groups are halogens.

[0060] In some preferred embodiments of the present invention, in formula (1),

[0061] R 1 R 2 and R 3 Each independently chooses H and C. 1-10 hydrocarbon group, C 1-10 The group consisting of alkoxy groups and halogens; more preferably, R 1 R 2 and R 3 Each independently chooses H and C. 1-6 alkyl, C 1-6 The group consisting of alkoxy groups and halogens;

[0062] R1 and R2 are each independently selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, phenyl, naphthyl, and C substituted with at least one of the following substituents: methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl. 7-14 The group consisting of aryl groups; more preferably, R1 and R2 are each independently selected from phenyl, naphthyl, and C groups substituted with at least one substituent selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl. 7-14 A group consisting of aryl groups;

[0063] Mt can be Ti, Zr, or Hf;

[0064] X is selected from at least one group from the group consisting of methyl, ethyl, n-propyl, isopropyl, cyclopentadienyl, fluorine, chlorine, bromine, and iodine.

[0065] In this invention, m is 1, 2 or 3.

[0066] In this invention, n is 2.

[0067] In this invention, the nitrogen- and phosphine-containing metal compounds are pre-transition metal compounds containing nitrogen and phosphine, which can be combined with activators to form catalyst compositions for use in catalytic olefin polymerization reactions, particularly in catalytic ethylene homopolymerization and / or ethylene-α-olefin copolymerization reactions. When this catalyst composition is used to catalyze olefin polymerization reactions, it has the advantages of high catalytic activity and suitability for preparing high-density polyethylene and ethylene-α-olefin elastomers.

[0068] A second aspect of the present invention provides a method for preparing a nitrogen- and phosphine-containing metal compound, the method comprising:

[0069] 1) In the presence of an organic solvent, the compound with the structure shown in formula (11) is reacted with n-butyllithium to obtain a first intermediate;

[0070] 2) The first intermediate is reacted with the compound with the structure shown in formula (12) in a second reaction to obtain the second intermediate;

[0071] 3) The second intermediate is reacted with trimethylazidosilane in a third reaction to obtain a third intermediate having the structure shown in formula (13);

[0072] 4) The third intermediate is reacted with the compound with the structure shown in formula (14) in a fourth reaction to obtain the fourth intermediate with the structure shown in formula (15);

[0073] 5) Combine the fourth intermediate with Cp*MtX (n+1) The fifth reaction is carried out to obtain the fifth intermediate;

[0074] 6) The fifth intermediate is reacted with a Grignard reagent in a sixth reaction to obtain a metal compound having the structure shown in formula (1);

[0075]

[0076] Among them, equations (11), (12), (13), (14), and (15) Cp*MtX (n+1) The definition of the substituent in formula (1) is the same as that in the first aspect mentioned above, and X1 in formula (12) is a halogen.

[0077] In this invention, the first compound obtained from the first reaction in step 1) is a lithium salt. The lithium salt can be directly introduced into step 2) for the second reaction, or it can be separated and purified before being introduced into step 2) for the second reaction. This invention does not particularly limit the separation and purification steps, and those skilled in the art can use conventional methods in the art, such as recrystallization and column chromatography, to perform separation and purification.

[0078] In some embodiments of the present invention, compounds with the structure shown in formula (11) are used in combination with n-butyllithium, compounds with the structure shown in formula (12), trimethylazidosilane, compounds with the structure shown in formula (14), and Cp*MtX. (n+1) The molar ratio of the reagent to the Grignard reagent is 1:1-2:1-2:1-4:2-10:1-2:1-5; for example, 1:1.2:1:2:6:1:2, 1:1:1:2:5:1:3, 1:2:2:4:8:2:4, and any value within the range of any two values.

[0079] In some embodiments of the present invention, the molar ratio of the second compound to trimethylazidosilane is 1:(0.8-2).

[0080] In some embodiments of the present invention, in step 1), the organic solvent is selected from at least one of toluene, hexane, pentane, benzene, xylene, dichloromethane, trichloromethane, tetrachloromethane, and tetrahydrofuran.

[0081] In some embodiments of the present invention, in step 5), Cp*MtX (n+1) Preferred Cp*MtCl 3， If Mt is Ti, Zr, or Hf, then Cp*MtCl3 is Cp*TiCl3, Cp*ZrCl3, or Cp*HfCl3.

[0082] In some embodiments of the present invention, in step 6), the Grignard reagent is selected from at least one of methyl magnesium bromide, ethyl magnesium bromide, isopropyl magnesium bromide, and phenyl magnesium bromide.

[0083] In some embodiments of the present invention, the conditions for the first reaction include: a reaction temperature of -100°C to 100°C and a reaction time of 0.5-2 hours.

[0084] In some embodiments of the present invention, the conditions for the second reaction include: a reaction temperature of -100°C to 40°C and a reaction time of 0.5-3 hours.

[0085] In some embodiments of the present invention, the conditions for the third reaction include: a reaction temperature of 50-200°C and a reaction time of 1-20 h.

[0086] In some embodiments of the present invention, the conditions for the fourth reaction include: a reaction temperature of 50-200°C and a reaction time of 2-30 h.

[0087] In some embodiments of the present invention, the conditions for the fifth reaction include: a reaction temperature of 50-200°C and a reaction time of 2-30 h.

[0088] In some embodiments of the present invention, the conditions for the sixth reaction include: a reaction temperature of 50-200°C and a reaction time of 2-30 h.

[0089] The preparation method described above may further include necessary post-processing steps. Those skilled in the art can use various steps conventionally used in the art to perform post-processing to purify the crude products from each step. For example, the post-processing steps may include solvent removal, washing, and drying.

[0090] A third aspect of the present invention provides a nitrogen- and phosphine-containing metal compound prepared by the preparation method described in the second aspect above.

[0091] A fourth aspect of the present invention provides a catalyst composition for olefin polymerization, the catalyst composition comprising a main catalyst and an activator; wherein the main catalyst is a nitrogen- and phosphine-containing metal compound as described in any one of the first and third aspects above; and the activator comprises an aluminum-containing compound and optionally an organoboron compound.

[0092] In some embodiments of the present invention, the activator comprises an aluminum-containing compound, and the molar ratio of the main catalyst, calculated as metal element, to the aluminum-containing compound, calculated as aluminum element, is 1:(0.1-3000), preferably 1:(50-1000).

[0093] In other embodiments of the present invention, the activator comprises an aluminum-containing compound and an organoboron compound, wherein the molar ratio of the main catalyst, the aluminum-containing compound, and the organoboron compound, calculated as metal elements, is 1:(5-500):(1-5), preferably 1:(5-200):(1-5.

[0094] In some embodiments of the present invention, the aluminum-containing compound is a mixture of alkylaluminum compounds and alkylaluminoxane compounds or an alkylaluminoxane compound.

[0095] Preferably, in the mixture of the alkylaluminum compound and the alkylaluminoxane compound, the molar ratio of the alkylaluminum compound (calculated as aluminum) to the alkylaluminoxane compound (calculated as aluminum) is 1:(10-500); more preferably, it is 1:(25-300).

[0096] Preferably, the alkylaluminoxane compound has the structure shown in formula (3).

[0097]

[0098] In equation (3), R 31 It is at least one group selected from methyl, ethyl, n-propyl, isopropyl, primary butyl, secondary butyl, and tert-butyl; t is an integer from 5 to 30. More preferably, in R 31 It is at least one group selected from methyl, ethyl, n-propyl, isopropyl, and tert-butyl. More preferably, in formula (3), R... 31 It is at least one group selected from methyl, ethyl, and isopropyl. Preferably, the alkylaluminoxane compound is methylaluminoxane (MAO) and / or isobutylaluminoxane, that is, R 31 It is methyl or isobutyl.

[0099] In some preferred embodiments of the present invention, the alkylaluminum compound is selected from at least one of trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, trihexylaluminum, dimethylaluminum chloride, diethylaluminum chloride, dipropylaluminum chloride, diisobutylaluminum chloride, dihexylaluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, propylaluminum dichloride, isobutylaluminum dichloride, hexylaluminum dichloride, dimethylaluminum hydride, diethylaluminum hydride, dipropylaluminum hydride, diisobutylaluminum hydride, and dihexylaluminum hydride. Preferably, the alkylaluminum compound is triisobutylaluminum.

[0100] In some preferred embodiments of the present invention, the organoboron compound is selected from at least one of tris(pentafluorophenyl)boron (B(C6F5)3), N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate ([HNMe2Ph][B(C6F5)4]), and triphenylcarbamonite tetra(pentafluorophenyl)borate ([Ph3C][B(C6F5)4]).

[0101] The catalyst composition for olefin polymerization of the present invention may also contain other necessary additives, as long as these additives do not affect the catalytic effect of the composition. For example, the composition may contain an impurity remover.

[0102] The catalyst provided in the fourth aspect of the present invention exhibits excellent catalytic activity in the catalytic polymerization of olefins and is suitable for the preparation of high-density polyethylene and ethylene-α-olefin elastomers.

[0103] The fifth aspect of the present invention provides the use of the catalyst composition for olefin polymerization described in the fourth aspect above in catalytic olefin polymerization reactions; particularly in catalytic ethylene homopolymerization and / or ethylene-α-olefin copolymerization reactions.

[0104] In this application of the invention, there are no particular limitations on the order and method of adding the components to form the catalyst composition for olefin polymerization. The main catalyst, activator, and optional additives can be pre-mixed and added to the polymerization reaction, or the main catalyst, activator, and optional additives can be added to the polymerization reaction separately. According to a preferred embodiment: the activator and optional additives are first added to the reaction system, then the olefin monomer is introduced, and finally the main catalyst is added.

[0105] The sixth aspect of the present invention provides a method for preparing an olefin polymer, the method comprising: in the presence of a solvent, reacting an olefin monomer with the catalyst composition for olefin polymerization described in the fourth aspect above to obtain an olefin polymer.

[0106] In some embodiments of the present invention, the concentration of the catalyst composition for olefin polymerization in the contact reaction system is 1 × 10⁻⁶. -6-1×10 -5 mol / L.

[0107] In this invention, since olefin monomers are generally in the gas phase and the reaction is solution polymerization, the amount of gaseous monomer dissolved in the solvent can be ensured by the gas pressure, the reaction ensures that the concentration of dissolved liquid monomer is constant, the gaseous monomer is continuously introduced into the liquid solvent, and the gas pressure is kept constant.

[0108] In some embodiments of the present invention, the olefin monomer is ethylene and / or α-olefin. Preferably, the α-olefin is at least one selected from propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-1-pentene.

[0109] In some embodiments of the present invention, the conditions for the contact reaction include: a temperature of -50°C to 200°C, a time of 0.1-6 h, and a pressure of 0.1-5 MPa.

[0110] Preferably, the conditions for the contact reaction include: a temperature of 20-100℃, a time of 0.2-5h, and a pressure of 0.1-2MPa. All pressures in this invention are gauge pressures.

[0111] The contact reaction described in this invention can be carried out by solution polymerization or bulk polymerization. The polymerization reaction of this invention can be a solution polymerization reaction. It will be apparent to those skilled in the art that the solvent used should be liquid under homopolymerization conditions and should not participate in the polymerization reaction or react with the resulting polymer; that is, the solvent should be inert. Such solvents are obvious to those skilled in the art of polymerization and can be easily selected. Nevertheless, specific examples of the organic solvent used in this invention include, for example, one or more of benzene, toluene, ethylbenzene, xylene, pentane, n-hexane, heptane, octane, and cyclohexane, preferably n-hexane, octane, or heptane, and more preferably n-hexane as the solvent in the homopolymerization reaction of this invention. For the polymerization reaction of this invention, the amount of solvent used results in a polymer concentration in the range of 5-30% by weight, preferably 8-10% by weight.

[0112] According to the present invention, the above-mentioned polymerization process is preferably carried out under an inert atmosphere, such as one or more of nitrogen, helium, argon, etc., to provide such an inert atmosphere.

[0113] In the polymerization reaction of this invention, a terminator can be used to terminate the polymerization reaction after it is completed. The terminator used for this step is conventional to those skilled in the art. Commonly used terminators include deionized water, alcohols, acids, etc. In this invention, the preferred terminator is one or more of isopropanol, methanol, water, etc.

[0114] In particular, the olefin polymerization reaction catalyzed by the aforementioned catalyst of the present invention can achieve high catalytic efficiency, while simultaneously obtaining ethylene-α-olefin elastomers. The method for preparing ethylene-α-olefin copolymers of the present invention is simple to operate and has a low catalyst cost.

[0115] More specifically, the above preparation method, when using the composition of the present invention as a catalyst, can produce ethylene-propylene copolymers with higher catalytic efficiency, for example, the catalytic efficiency can reach 10. 6 g polymer / (mol·metal·h).

[0116] The present invention will be described in detail below through examples.

[0117] Unless otherwise specified, all raw materials used in the following preparation examples, embodiments and comparative examples are commercially available.

[0118] The number-average molecular weight Mn, weight-average molecular weight Mw, and molecular weight distribution index (PDI = Mw / Mn) of the polymers described below were determined by Waters 150 gel permeation chromatography (GPC) at 135 °C using 1,2,4-trichlorobenzene as the mobile phase.

[0119] Tg and Tm: The glass transition temperature (Tg) and melting point (Tm) of the polymer were measured using a METTLER DSC thermal analyzer. The temperature was first increased from room temperature to 200°C at a rate of 20°C / min, then decreased to -100°C, and then increased again to 150°C at a rate of 20°C / min.

[0120] Polymerization activity (also known as catalytic efficiency) refers to the mass of polymer obtained per unit molar amount of Mt, expressed in g / (mol·Mt·h). For example, if Mt is Ti, the corresponding unit is g / (mol·Ti·h).

[0121]

[0122] Among them, R 1 It is methyl, R 2 It is isopropyl, R 3 The group is isopropyl, m=2, R1 is phenyl, R2 is phenyl, Mt is Ti, X is chloro or methyl, n=2.

[0123] Preparation Example 1

[0124] The preparation method of the ligand with the structure shown in formula (A1) includes the following steps:

[0125] 1) Dissolve diphenylphosphine chloride (28.4 mmol) in 20 mL of toluene, and slowly add a hexane solution (18.6 mL) of n-butyllithium (29.8 mmol) dropwise at -78 °C using liquid nitrogen. React for 2 h, then raise the temperature to 25 °C;

[0126] 2) Weigh 4-bromobutane-2-one (4.29 g, 28.4 mmol), dissolve it in 100 mL of anhydrous diethyl ether, and react it with the lithium salt solution prepared in 1) at -78 °C for 2 h. Then, slowly heat the solution to 25 °C and continue the reaction for 12 h. After separation and purification, 5.09 g of a white solid, i.e., the ligand with the structure shown in formula (A1), is obtained. The yield is 67%.

[0127] Preparation Example 2

[0128] The preparation method of the ligand with the structure shown in formula (A2) includes the following steps:

[0129] Trimethylsilane N3SiMe3 (0.015 mol) was slowly added to 20 mL of a toluene solution containing 5 mmol of the ligand with the structure shown in formula (A1) obtained in Preparation Example 1. The reaction mixture was heated under reflux for 12 h. When the solvent and excess TMSN3 were removed by vacuum, a white crystalline solid was obtained, namely the ligand with the structure shown in (A2). The yield was 95%.

[0130] Preparation Example 3

[0131] The preparation method of the ligand with the structure shown in formula (A3) includes the following steps:

[0132] Di-o-isopropylaniline (0.015 mol) was slowly added to 20 mL of a toluene solution containing 5 mmol of the ligand with the structure shown in formula (A2) obtained in Preparation Example 2. The reaction mixture was heated under reflux for 12 h. After removing the solvent by vacuum, a white crystalline solid was obtained, namely the ligand with the structure shown in formula (A3). The yield was 85%.

[0133] Preparation Example 4

[0134] The preparation method of compound 1A' includes the following steps:

[0135] The ligand (1 mmol) with the structure shown in formula (A3) obtained in Preparation Example 3 was dissolved in 15 mL of toluene, stirred until homogeneous, and slowly added dropwise to 5 mL of a toluene solution containing cyclopentadiene titanium trichloride (2 mmol). The mixture was heated to 110 °C and reacted for 12 h, then cooled to 25 °C, and 0.81 g of a yellow powder was obtained, which is compound 1A' with the structure shown in formula (1A), wherein R 1 It is methyl, R 2 It is isopropyl, R 3The group is isopropyl, m=2, R1 is phenyl, R2 is phenyl, Mt is Ti, X is chlorine, and n=2.

[0136] Preparation Example 5

[0137] The preparation method of compound 1A includes the following steps:

[0138] At room temperature, compound 1A' (0.8 mmol) obtained in Preparation Example 4 was dissolved in 10 mL of diethyl ether, and a solution of methyl magnesium bromide (3.1 mmol) in diethyl ether was added dropwise with stirring. The reaction was carried out at room temperature for 12 h. The solvent was removed under reduced pressure, the product was washed three times with pentane, and dried under vacuum to obtain 0.4 g of the product, namely compound 1A with the structure shown in formula (1A), wherein R 1 It is methyl, R 2 It is isopropyl, R 3 The derivative is isopropyl, m=2, R1 is phenyl, R2 is phenyl, Mt is Ti, X is methyl, n=2. The yield is 89%.

[0139] Preparation Example 6

[0140] The preparation method of compound 1B' includes the following steps:

[0141] Ligand B3 was prepared according to the method of Preparation Examples 1-3. The difference is that, unlike the ligand with the structure shown in formula (A3), R in B3... 1 It is methyl, R 2 It is isopropyl, R 3 The ligand B3 (1 mmol) is isopropyl, m = 2, R1 is isopropyl, and R2 is isopropyl. Then, the prepared ligand B3 is dissolved in 10 mL of toluene, stirred until homogeneous, and slowly added dropwise to 5 mL of a toluene solution containing cyclopentadiene titanium trichloride (2 mmol). The mixture is heated to 100 °C and reacted for 15 h. Then, it is cooled to 25 °C, and a yellow powder, compound 1B', is obtained. Unlike compound A1 with the structure shown in formula (1A), in compound 1B', R... 1 It is methyl, R 2 It is isopropyl, R 3 The group is isopropyl, m=2, R1 is isopropyl, R2 isopropyl, Mt is titanium, X is chlorine, and n=2.

[0142] Preparation Example 7

[0143] The preparation method of compound 1B includes the following steps:

[0144] At room temperature, compound 1B' (0.8 mmol) obtained in Preparation Example 6 was dissolved in 10 mL of diethyl ether, and a solution of methyl magnesium bromide (3.1 mmol) in diethyl ether was added dropwise with stirring. The reaction was carried out at room temperature for 12 h. The solvent was removed under reduced pressure, the product was washed three times with pentane, and dried under vacuum to obtain compound 1B. Unlike compound 1A with the structure shown in formula (1A), in compound 1B, R... 1 It is methyl, R 2 It is isopropyl, R 3 The group is isopropyl, m=2, R1 is isopropyl, R2 isopropyl, Mt is titanium, X is methyl, n=2.

[0145] Preparation Example 8

[0146] Compound 1C was prepared according to the method of Preparation Examples 1-5. Unlike compound 1A with the structure shown in formula (1A), in 1C, R 1 It is a phenyl group, R 2 It is isopropyl, R 3 Mt is methyl, m=3, R1 is tert-butyl, R2 is tert-butyl, Mt is zirconium, X is methyl, n=2.

[0147] Preparation Example 9

[0148] Compound 1D was prepared according to the method of Preparation Examples 1-5. Unlike compound 1A with the structure shown in formula (1A), in 1D, R 1 It is a phenyl group, R 2 It is isopropyl, R 3 The group is isopropyl, m=2, R1 is tert-butyl, R2 is methyl, Mt is hafnium, X is methyl, and n=2.

[0149] Example 1

[0150] Ethylene homopolymer (methylaluminoxane as activator):

[0151] Under nitrogen protection and at 50°C, 2 mL of a toluene solution of methylaluminoxane (2 mmol) (purchased from Albemarle) was added to 150 mL of toluene; ethylene gas was continuously introduced at a flow rate of 50 L / h and the gauge pressure was maintained at 0.6 MPa. Then, compound 1A' (0.03 mmol) prepared in Preparation Example 4 was added, and polymerization was carried out for 15 min. The monomer supply was then stopped. The reaction was terminated with isopropanol, and the resulting polymer was dried in an oven after removing the solvent. The results are shown in Table 1.

[0152] Example 2

[0153] Ethylene homopolymer (methylaluminoxane and organoboron compounds as activators):

[0154] Under nitrogen protection and at 50°C, 5 mL of a toluene solution containing 5 mmol of methylaluminoxane was added to 150 mL of toluene. Ethylene gas was continuously introduced at a flow rate of 50 L / h, maintaining a gauge pressure of 0.6 MPa. Then, 5 mL of a toluene solution containing 0.04 mmol of the [CPh3][B(C6F5)4] compound co-catalyst was added, followed by 0.02 mmol of compound 1A obtained in Preparation Example 5. Polymerization was carried out for 15 min, after which monomer supply was stopped. The reaction was terminated with isopropanol, and the resulting polymer was dried in an oven after removing the solvent. The results are shown in Table 1.

[0155] Example 3

[0156] Ethylene homopolymer (methylaluminoxane and organoboron compounds as activators):

[0157] Under nitrogen protection and at 50°C, 1 mL of a toluene solution containing 1 mmol of methylaluminoxane was added to 150 mL of toluene. Ethylene gas was continuously introduced at a flow rate of 50 L / h, maintaining a gauge pressure of 0.6 MPa. 2.5 mL of a toluene solution containing 0.02 mmol of the [CPh3][B(C6F5)4] compound co-catalyst was added, followed by 0.02 mmol of compound 1B obtained in Preparation Example 6. Polymerization was carried out for 15 min, after which monomer supply was stopped. The reaction was terminated with isopropanol, and the resulting polymer was dried in an oven after removing the solvent. The results are shown in Table 1.

[0158] Example 4

[0159] Ethylene-propylene copolymer (methylaluminoxane as activator):

[0160] Under nitrogen protection and at 50°C, 6 mL of a toluene solution containing 6 mmol of methylaluminoxane was added to 150 mL of toluene. An ethylene / propylene / hydrogen mixture (molar ratio 1:1.5:0.05, flow rate 50 L / h, gauge pressure maintained at 0.6 MPa) was continuously purged. Then, compound 1A' (0.03 mmol) obtained in Preparation Example 4 was added, and polymerization was carried out for 15 min. The monomer supply was then stopped. The reaction was terminated with isopropanol, and an antioxidant such as Irganox 1520 was added (the amount was such that the antioxidant content in the polymer was 0.2% by weight, purchased from BASF). The resulting polymer was desolventized and dried in an oven. The results are shown in Table 1.

[0161] Example 5

[0162] Ethylene-propylene copolymer (methylaluminoxane as activator):

[0163] This embodiment was carried out using a method similar to that of Example 4, except that an equal molar amount of compound 1B' obtained from Preparation Example 6 was used to replace compound 1A' with the structure shown in formula (1A) in Example 4. Everything else was the same as in Example 4. The results are shown in Table 1.

[0164] Example 6

[0165] Ethylene-propylene copolymerization (using methylaluminoxane and organoboron compounds as activators):

[0166] Under nitrogen protection and at 70°C, 2 mL of a toluene solution containing 2 mmol of methylaluminoxane was added to 150 mL of toluene. An ethylene / propylene / hydrogen mixture (molar ratio 1:1.5:0.01, flow rate 50 L / h) was continuously purged while maintaining a gauge pressure of 0.6 MPa. 2.5 mL of a toluene solution containing 0.02 mmol of the [CPh3][B(C6F5)4] compound co-catalyst was added, followed by 0.02 mmol of compound 1B obtained in Preparation Example 7. Polymerization was carried out for 15 min, and monomer supply was stopped. The reaction was terminated with isopropanol, and an antioxidant such as Irganox 1520 was added (in an amount such that the antioxidant content in the polymer was 0.2 wt%). The resulting polymer was desolventized and oven-dried. The results are shown in Table 1.

[0167] Example 7

[0168] This embodiment was carried out using a method similar to that of Example 3, except that an equal molar amount of compound 1C obtained from Preparation Example 8 was used to replace compound 1B in Example 3. Everything else was the same as in Example 3. The results are shown in Table 1.

[0169] Example 8

[0170] This embodiment was carried out using a method similar to that of Example 3, except that an equal molar amount of compound 1D prepared in Example 9 was used to replace compound 1B in Example 3. Everything else was the same as in Example 3. The results are shown in Table 1.

[0171] Comparative Example 1

[0172] This comparative example was conducted using a method similar to that of Example 1, except that an equimolar amount of Fe(III) complex D1 was used to replace compound 1A' in Example 1. Everything else was the same as in Example 1. The results are shown in Table 1.

[0173] The Fe(III) complex D1 can be found in Example 8 of US6239237B1, which contains the Fe(III) complex (IIIa), and its preparation method is as follows:

[0174] The ligand (1 equivalent) with the structure shown in the following formula was added together with FeCl3 into a Schienk flask in a drying oven, and then THF (30 mL) was added to the flask; the mixture was stirred until no metal salt was observed in the flask; the reaction solution was filtered to remove some insoluble polymer material and concentrated; then heptane (5 mL) was added to precipitate the complex; the resulting solid was filtered, washed with heptane and dried under vacuum.

[0175]

[0176] Comparative Example 2

[0177] This comparative example was conducted using a method similar to that of Example 3, except that an equimolar amount of Fe(III) complex D1 (same as Comparative Example 1) was used to replace compound 1B in Example 3. Everything else was the same as in Example 3. The results are shown in Table 1.

[0178] Table 1

[0179]

[0180]

[0181] As can be seen from the results in Table 1, the complexes provided by the present invention can obtain ethylene homopolymers and ethylene-α-olefin copolymer elastomers with high catalytic activity over a wide range. In particular, the complexes provided by the present invention exhibit high catalytic activity even at low reaction pressures.

[0182] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A nitrogen- and phosphine-containing metal compound, characterized in that, The metal compound has the structure shown in formula (1). In equation (1), R 1 R 2 and R 3 Each independently chooses H and C. 1-20 hydrocarbon group, C 1-20 The group consisting of alkoxy groups and halogens; R1 and R2 are each independently chosen from H and C. 1-4 hydrocarbon group, C 6-12 aryl and C 1-4 hydrocarbon group substituted C 7-16 A group consisting of aryl groups; m is 1, 2, or 3; Mt is a Group IVB metallic element; Cp* is a cyclopentadienyl group containing an electron-donating substituent; X is an atom or group bonded to the Mt element, and X is selected from C. 1-10 It is at least one group in the group consisting of a hydrocarbon group and a halogen; n is an integer and satisfies the Mt bond valence.

2. The metal compound according to claim 1, wherein, In equation (1), R 1 R 2 and R 3 Each independently chooses H and C. 1-16 hydrocarbon group, C 1-16 The group consisting of alkoxy groups and halogens; R1 and R2 are each independently chosen from H and C. 1-4 hydrocarbon group, C 6-10 aryl and C 1-4 hydrocarbon group substituted C 7-14 A group consisting of aryl groups; Mt can be Ti, Zr, or Hf; X chooses freely C 1-8 At least one group from the group consisting of hydrocarbon groups, fluorine, chlorine, bromine and iodine; Preferably, in formula (1), R 1 R 2 and R 3 Each independently chooses H and C. 1-10 hydrocarbon group, C 1-10 The group consisting of alkoxy groups and halogens; R1 and R2 are each independently selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, phenyl, naphthyl, and C substituted with at least one of the substituents selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl. 7-14 A group consisting of aryl groups; X is selected from at least one group from the group consisting of methyl, ethyl, n-propyl, isopropyl, cyclopentadienyl, fluorine, chlorine, bromine and iodine; More preferably, in equation (1), R 1 R 2 and R 3 Each independently chooses H and C. 1-6 alkyl, C 1-6 The group consisting of alkoxy groups and halogens; R1 and R2 are each independently selected from phenyl, naphthyl, and C, which are substituted with at least one of the following substituents: methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl. 7-14 A group consisting of aryl groups.

3. A method for preparing a nitrogen- and phosphine-containing metal compound, characterized in that, The preparation method includes: 1) In the presence of an organic solvent, the compound with the structure shown in formula (11) is reacted with n-butyllithium to obtain a first intermediate; 2) The first intermediate is reacted with the compound with the structure shown in formula (12) in a second reaction to obtain the second intermediate; 3) The second intermediate is reacted with trimethylazidosilane in a third reaction to obtain a third intermediate having the structure shown in formula (13); 4) The third intermediate is reacted with the compound with the structure shown in formula (14) in a fourth reaction to obtain the fourth intermediate with the structure shown in formula (15); 5) Combine the fourth intermediate with Cp*MtX (n+1) The fifth reaction is carried out to obtain the fifth intermediate; 6) The fifth intermediate is reacted with a Grignard reagent in a sixth reaction to obtain a metal compound having the structure shown in formula (1); Among them, equations (11), (12), (13), (14), and (15) Cp*MtX (n+1) The definition of the substituent in formula (1) is the same as that in claim 1 or 2, and X1 in formula (12) is a halogen.

4. The preparation method according to claim 3, wherein, Compounds with the structure shown in formula (11) and n-butyllithium, compounds with the structure shown in formula (12), trimethylazidosilane, compounds with the structure shown in formula (14), and Cp*MtX (n+1) The molar ratio of the reagent to the Grignard reagent is 1:1-2:1-2:1-4:2-10:1-2:1-5; And / or, in step 1), the organic solvent is selected from at least one of toluene, hexane, pentane, benzene, xylene, dichloromethane, chloroform, tetrachloromethane, and tetrahydrofuran; And / or, in step 5), Mt is Ti, Zr, or Hf; And / or, in step 6), the Grignard reagent is selected from at least one of methyl magnesium bromide, ethyl magnesium bromide, isopropyl magnesium bromide, and phenyl magnesium bromide.

5. The preparation method according to claim 3 or 4, wherein, The conditions for the first reaction include: a reaction temperature of -100℃ to 100℃ and a reaction time of 0.5-2h; And / or, the conditions for the second reaction include: a reaction temperature of -100°C to 40°C and a reaction time of 0.5-3 hours; And / or, the conditions for the third reaction include: a reaction temperature of 50-200°C and a reaction time of 1-20 h; And / or, the conditions for the fourth reaction include: a reaction temperature of 50-200℃ and a reaction time of 2-30h; And / or, the conditions for the fifth reaction include: a reaction temperature of 50-200℃ and a reaction time of 2-30h; And / or, the conditions for the sixth reaction include: a reaction temperature of 50-200℃ and a reaction time of 2-30h.

6. A nitrogen- and phosphine-containing metal compound prepared by the preparation method according to any one of claims 3-5.

7. A catalyst composition for olefin polymerization, characterized in that, The catalyst composition comprises a main catalyst and an activator; wherein the main catalyst is a nitrogen- and phosphine-containing metal compound as described in any one of claims 1, 2 and 6; and the activator comprises an aluminum-containing compound and optionally an organoboron compound.

8. The catalyst composition according to claim 7, wherein, The activator includes an aluminum-containing compound, and the molar ratio of the main catalyst (calculated as metal element) to the aluminum-containing compound (calculated as aluminum element) is 1:(0.1-3000), preferably 1:(50-1000). Alternatively, the activator may include an aluminum-containing compound and an organoboron compound, wherein the molar ratio of the main catalyst (calculated as metal element), the aluminum-containing compound (calculated as aluminum element), and the organoboron compound (calculated as boron element) is 1:(5-500):(1-5), preferably 1:(5-200):(1-5).

9. The catalyst composition according to claim 7 or 8, wherein, The aluminum-containing compound is a mixture of alkylaluminum compounds and alkylaluminoxane compounds or an alkylaluminoxane compound; preferably, the alkylaluminoxane compound is methylaluminoxane and / or isobutylaluminoxane, and the alkylaluminum compound is selected from at least one of trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, trihexylaluminum, dimethylaluminum chloride, diethylaluminum chloride, dipropylaluminum chloride, diisobutylaluminum chloride, dihexylaluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, propylaluminum dichloride, isobutylaluminum dichloride, hexylaluminum dichloride, dimethylaluminum hydride, diethylaluminum hydride, dipropylaluminum hydride, diisobutylaluminum hydride, and dihexylaluminum hydride; The organoboron compound is selected from at least one of tris(pentafluorophenyl)boron, N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate, and triphenylcarbamonium tetra(pentafluorophenyl)borate.

10. The use of the catalyst composition for olefin polymerization according to any one of claims 7-9 in catalytic olefin polymerization reactions; particularly in catalytic ethylene homopolymerization and / or ethylene-α-olefin copolymerization reactions.

11. A method for preparing olefin polymers, characterized in that, The method comprises: in the presence of a solvent, contacting an olefin monomer with a catalyst composition for olefin polymerization according to any one of claims 7-9 to obtain an olefin polymer.

12. The method according to claim 11, wherein, In the contact reaction system, the concentration of the catalyst composition for olefin polymerization is 1×10⁻⁶. -6 -1×10 -5 mol / L; And / or, the olefin monomer is ethylene and / or α-olefin; And / or, the conditions for the contact reaction include: a temperature of -50°C to 200°C, a time of 0.1-6 h, and a pressure of 0.1-5 MPa.

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