CN1125088C - Transition metal catalyst containing acacyclopentadiene in its ligand and its preparing process and application - Google Patents

Abstract

A kind of olefin polymerization catalyst, has following general formula expression: In the formula, L is the ligand group containing azocene skeleton or diazocene skeleton, and the two nitrogen atoms in described diazepine skeleton are Arranged in the meta or ortho position, there can be 1 to 4 substituents on the azocene skeleton, Cp is a ligand group containing a cyclopentadiene skeleton, M is titanium or zirconium, X and Y are selected from halogen, C ₁ -C ₂₄ alkyl, alkoxy, siloxy or alkaryl. The catalyst is used in the homopolymerization or copolymerization of α-olefins, such as the homopolymerization or copolymerization of ethylene or styrene, in combination with cocatalyst alkyl aluminoxane.

Description

Transition metal catalyst containing nitrogen heterocene in ligand and its preparation method and application

The invention relates to a polyolefin catalyst and its preparation method and application, in particular to a semi-metallocene polyolefin catalyst using azolocene derivatives as a phenocene ligand and its preparation method and application.

In recent years, the use of metallocene catalysts in olefin polymerization to produce polyolefins has been widely known. The ligands of the metallocene catalysts are cyclopentadiene and its derivatives, and the metals are transition metals. It is now found that transition metal compounds containing large ligands such as oxygen, nitrogen, and sulfur have higher polymerization activity than metallocenes. USP5,539,124 discloses a transition metal complex catalyst containing a pyrrole ring, the general formula is: (L)m(Cp)qM(Y)n(B)p. In the formula, L is a condensed ring ligand containing a pyrrole ring, or a mixture of ligands, Cp is cyclopentadienyl or alkyl-substituted cyclopentadienyl, B is Lewis base, Y is hydrogen, C ₁ ~ C ₂₀ alkoxy, C ₁ -C ₂₀ siloxy or a mixture of the two, M is Ti, Zr or a mixture thereof, wherein m is 2 to 4, that is to say, the number of ligands L is at least 2. n is 0-1, p is 0-2, q is 0-1, m+n+q=4, and m+q=3 or 4. The catalyst can be used to catalyze the polymerization of olefins, such as the polymerization of ethylene, but the catalytic activity is relatively low, which is equivalent to the production of 1.5 kg of polyethylene per gram of catalyst per hour.

CN1151993A discloses a novel metallocene catalyst for ethylene polymerization, which uses pyrrolyl or its derivatives as a transition metal ligand, and uses sesquiethylaluminum as a cocatalyst during ethylene polymerization instead of aluminoxane as a cocatalyst , showing higher catalytic activity, the obtained polyethylene has low molecular weight and narrow molecular weight distribution. For example, with dipyrrolyl titanium dichloride as the main catalyst for polymerization, at a reaction temperature of 50°C, an ethylene pressure of 0.04 MPa, and a reaction time of 7 hours, the polymerization activity is 3.4×10 ⁵ g polyethylene/mol titanium, and the molecular weight distribution is 1.47.

The purpose of the present invention is to provide a transition metal complex catalyst containing azolocene in the ligand, which has higher catalytic activity.

Another object of the present invention is to provide a preparation method of the above-mentioned catalyst.

Another object of the present invention is to provide the use of the above catalyst in polyene polymerization.

Olefin polymerization catalyst of the present invention has following general formula expression:

In the formula, L is a ligand group containing azocene skeleton or diazepine skeleton. There are 1 to 4 substituents R ₁ on the five-membered ring of the heterocene skeleton, and the two adjacent substituents on the skeleton can be connected to each other to form a more than two-membered condensed ring, and the condensed ring formed with the azacene is also It may contain nitrogen atoms; Cp is a ligand group containing a cyclopentadiene skeleton, and there are 1 to 5 substituents R ₂ on the cyclopentadiene skeleton, and two adjacent substituents on the skeleton can be connected to each other to form A condensed ring with more than two members; said R ₁ and R ₂ are respectively selected from hydrogen, C ₁ -C ₁₈ alkyl or perfluoroalkyl, C ₆ -C ₂₄ aralkyl or alkaryl, and M is selected from From Group IVB metals, X and Y are respectively selected from halogen, C ₁ -C ₂₄ alkyl, alkoxy, silyl or alkaryl.

Said M is preferably titanium or zirconium, and X and Y are preferably halogen or benzyl.

R ₁ and R ₂ are preferably hydrogen, C ₁ -C ₆ alkyl, C ₁ -C ₆ perfluoroalkyl, C ₆ -C ₂₄ aralkyl or alkaryl.

The ligand L is selected from ligands containing an azacene skeleton, and there are 1 to 4 substituents on the azacene five-membered ring skeleton, and two adjacent substituents can be connected to each other and form a A fused ring, and a nitrogen atom may also be contained in the condensed ring formed with azapine. Such ligands include pyrrolyl, indolyl, carbazolyl, 7-azaindolyl, or the above-mentioned groups containing single or multiple substituents, and the substituents are C ₁ -C ₆ alkane group or perfluoroalkyl group. Ligand L can also be selected from the ligands containing diazepine skeleton, and so-called diazepine refers to the group formed by the carbon atom on the cyclopentadiene skeleton being substituted by two nitrogen atoms, the pentazocene of diazepine There can be 1 to 3 substituents on the membered ring, and adjacent substituents can be connected to each other to form a condensed ring with diazepine. Such ligands include imidazolyl, pyrazolyl, benzimidazolyl, and indazolyl. , or the above-mentioned groups containing single or multiple substituents, and the substituents are C ₁ -C ₆ alkyl groups or perfluoroalkyl groups.

The Cp is preferably cyclopentadienyl, indenyl, fluorenyl, or the above-mentioned groups that are monosubstituted or multisubstituted, and the substituents are C ₁ -C ₈ alkyl or perfluoroalkyl.

Catalysts provided by the present invention are preferably: (pyrrolyl) (cyclopentadienyl) titanium dichloride, (indolyl) (cyclopentadienyl) titanium dichloride, (carbazolyl) (cyclo Pentadienyl)titanium dichloride, (7-azaindolyl)(cyclopentadienyl)titanium dichloride, (imidazolyl)(cyclopentadienyl)titanium dichloride, (benzo Imidazolyl)(cyclopentadienyl)titanium dichloride, (indazolyl)(cyclopentadienyl)titanium dichloride, (pyrazolyl)(cyclopentadienyl)titanium dichloride; ( Pyrrolyl)(pentamethyl-cyclopentadienyl)titanium dichloride, (indolyl)(pentamethyl-cyclopentadienyl)titanium dichloride, (carbazolyl)(pentamethylcyclo -pentadienyl)titanium dichloride, (7-azaindolyl)(pentamethyl-cyclopentadienyl)titanium dichloride, (imidazolyl)(pentamethyl-cyclopentadienyl ) titanium dichloride, (benzimidazolyl) (pentamethyl-cyclopentadienyl) titanium dichloride, (indazolyl) (pentamethyl-cyclopentadienyl) titanium dichloride, ( Pyrazolyl)(pentamethyl-cyclopentadienyl)titanium dichloride; (pyrrolyl)(tert-butyl-cyclopentadienyl)titanium dichloride, (indolyl)(tert-butyl- Cyclopentadienyl)titanium dichloride, (carbazolyl)(tert-butyl-cyclopentadienyl)titanium dichloride, (7-azaindoleyl)(tert-butyl-cyclopentadiene Base) titanium dichloride, (imidazolyl) (tert-butyl-cyclopentadienyl) titanium dichloride, (benzimidazolyl) (tert-butyl-cyclopentadienyl) titanium dichloride, ( Indazolyl) (tert-butyl-cyclopentadienyl) titanium dichloride, (pyrazolyl) (tert-butyl-cyclopentadienyl) titanium dichloride; (pyrrolyl) (indenyl) dichloride Titanium chloride, (indolyl)(indenyl)titanium dichloride, (carbazolyl)(indenyl)titanium dichloride, (7-azaindolyl)(indenyl)titanium dichloride, (Imidazolyl)(indenyl)titanium dichloride, (benzimidazolyl)(indenyl)titanium dichloride, (indazolyl)(indenyl)titanium dichloride, (pyrazolyl)(indenyl) ) titanium dichloride; (pyrrolyl) (fluorenyl) titanium dichloride, (indolyl) (fluorenyl) titanium dichloride, (carbazolyl) (fluorenyl) titanium dichloride, (7- Azaindolyl)(fluorenyl)titanium dichloride, (imidazolyl)(fluorenyl)titanium dichloride, (benzimidazolyl)(fluorenyl)titanium dichloride, (indazolyl)(fluorenyl)titanium dichloride base) titanium dichloride, (pyrazolyl) (fluorenyl) titanium dichloride.

The catalyst of the present invention can be prepared by a variety of methods, such as reacting a nitrogen-containing ligand compound with a strong basic compound to generate a ligand salt, and then using the ligand salt and cyclopentadiene or its derivatives as a ligand Transition metal halides, alkyls, alkoxy compounds, siloxy compounds, and alkaryl compounds react to prepare catalysts; or on the contrary, first react cyclopentadiene ligand compounds with strong basic compounds to form rings Pentadiene ligand salt, and then react the salt with nitrogen or derivatives thereof as transition metal halides, alkylates, alkoxy compounds, silicon oxide compounds, alkaryl compounds Get a catalyst. The present invention can also be directly prepared by reacting halides, alkylates, alkoxy compounds, siloxy compounds, alkaryl compounds of cyclopentadiene ligand compounds or derivatives thereof with nitrogen-containing ligand compounds. , but this reaction is best carried out in the presence of tertiary amines.

The first preparation method of catalyst of the present invention comprises the steps:

(1) In an ether solvent, equimolar amounts of strongly basic compound and ligand compound HL are fully contacted, and then the solvent is removed to obtain the salt of the ligand compound,

(2) In an organic solvent, equimolar amounts of the salt of the above ligand compound and the compound of the general formula CpMX ₂ Y are fully contacted, the solid matter is removed, and the solvent in the obtained liquid is removed to obtain the catalyst.

The symbols used in the expressions of the compounds used in the methods are as defined for the catalysts. During the preparation process (1), the reaction temperature in step (1) is -80-100°C, preferably -20-80°C, and the amount of ether solvent should be 10-20 times the weight of the ligand compound HL. The reaction time is preferably 0.5 to 48 hours, preferably 2 to 24 hours.

The temperature of the step (2) reaction is preferably -80 to 150°C, preferably -20 to 80°C, and the reaction time is 0.5 to 96 hours, preferably 2 to 48 hours. The amount of the organic solvent during the reaction is preferably 10 to 20 times the total weight of the reactants.

The second preparation method of catalyst of the present invention comprises the following steps:

(1) in an ether solvent, make the strongly basic compound of equimolar amount and cyclopentadiene type ligand compound fully contact reaction, remove solvent to obtain the salt of cyclopentadiene type ligand compound,

(2) In an organic solvent, the LMX ₃ and the salt of the cyclopentadiene ligand compound are fully stirred and contacted in an equimolar ratio under stirring conditions, and the solid matter is removed, and the solvent in the obtained liquid is removed to obtain the catalyst.

The symbols of the compound formula used in the above method are defined the same as the catalyst. The temperature of the step (1) reaction is preferably controlled at -80 to 100°C, preferably -20 to 80°C. The reaction time is 0.5 to 48 hours, preferably 1 to 24 hours. The amount of the ether solvent should be 10 to 20 times the weight of the ligand compound.

The reaction temperature of step (2) is preferably -80 to 150°C, preferably -20 to 80°C, and the reaction time is 0.5 to 96 hours, preferably 1 to 48 hours. The amount of the organic solvent during the reaction is preferably 10 to 20 times the total weight of the reactants.

The transition metal compound LMX ₃ containing azacene ligand in the above method is prepared by the following method, at -80 to 100°C, preferably -20 to 50°C, adding an equimolar ratio of transition metal compound to a dry organic solvent MX ₄ and the ligand compound HL containing the azocene skeleton, after stirring evenly, then add an equimolar amount of trialkylamine to react with HL, then concentrate the filtrate to remove insoluble solids, and then add the solvent of the obtained solution Remove that to get LMX ₃ . Wherein the symbol definitions in the general formula of the compound used are the same as that of the catalyst.

The trialkylamine mentioned in the process of preparing LMX ₃ can be triethylamine, tripropylamine, etc., preferably triethylamine, adding trialkylamine can shorten the reaction time, and the general reaction time in this preparation process is 0.5～ 96 hours, preferably 0.5 to 48 hours.

The said LMX ₃ can also be prepared by the following method: first, the ligand compound HL containing the azocene skeleton and the strong basic compound are reacted in an ether solvent in an equimolar ratio, and the reaction temperature is -80 to 100°C , preferably at -20 to 80°C, to obtain the L ligand salt. Then, in an organic solvent, react the L ligand salt with the transition metal compound MX ₄ in an equimolar amount for 0.5 to 48 hours, the reaction temperature is -80 to 100°C, preferably -20 to 80°C, and filter to remove the insoluble matter after the reaction , concentrate the filtrate, and collect the solid.

The strongly basic compound described in the above method is selected from alkylmagnesium bromide, alkali metal, alkali metal alkylate or hydride. The alkali metal is preferably lithium, sodium or potassium, the alkyl group in the alkylate is preferably methyl, ethyl or butyl, such as butyllithium, and the alkyl group in the alkylmagnesium halide is preferably a C ₁ -C ₈ alkane Base or aralkyl, such as methylmagnesium bromide, butylmagnesium bromide, benzylmagnesium bromide. The ether solvent is preferably diethyl ether or tetrahydrofuran.

The third preparation method of the catalyst of the present invention includes: in an organic solvent, the compound of the general formula CpMX ₂ Y and the ligand compound HL are fully contacted in an equimolar ratio, and then add trialkylamine in an equimolar amount to HL , stirring the mixture well, removing the solid matter, and removing the solvent from the resulting liquid to obtain a catalyst.

In the third preparation method of the catalyst, the suitable reaction temperature is -80-150°C, preferably -50-80°C. The reaction time is 0.5 to 96 hours, preferably 1 to 48 hours. During the reaction, the amount of the organic solvent is generally controlled to be 10 to 20 times of the total reactants.

The organic solvent used in the preparation method is preferably ether, methylene chloride, chloroform or toluene.

The ligand compound HL mentioned in the above method is preferably pyrrole, indole, carbazole, 7-azaindole, imidazole, pyrazole, benzimidazole, indazole or the above compound containing single or multiple substituents Derivatives, the substituents are C ₁ -C ₆ alkyl groups or perfluoroalkyl groups.

The cyclopentadiene-type ligand compound is preferably cyclopentadiene, indene, fluorene, or derivatives of the above-mentioned compounds with single or multiple substituents, and the substituents are C ₁ -C ₈ Alkyl groups such as pentamethylcyclopentadiene, tert-butylcyclopentadiene, n-butylcyclopentadiene, ethylcyclopentadiene, propylcyclopentadiene, 1-methyl, 3-propylcyclopentadiene ene etc.

The catalyst provided by the invention is suitable for homopolymerization or copolymerization of α-olefin monomers, and aluminoxane, alkylaluminum, alkylaluminum halide or their mixtures are used as cocatalysts during polymerization. During the reaction, the molar ratio of the aluminum in the cocatalyst to the transition metal in the main catalyst is 10-10000, preferably 50-5000, more preferably 50-3000.

Aluminoxanes as cocatalysts can be linear or cyclic polymers, preferred aluminoxanes are methylalumoxane, ethylalumoxane or isobutylalumoxane; alkylaluminum is preferably trimethylalumoxane Aluminum, triethylaluminum or triisobutylaluminum, the alkylaluminum halide is preferably diethylaluminum monochloride or diethylaluminum sesquimonochloride. The most preferred cocatalyst is methylaluminoxane.

The α-olefin monomer used for polymerization is preferably a C ₂ -C ₁₄ olefin, such as ethylene, propylene, styrene or a mixture of any two of them. The catalyst of the present invention can be used to produce polyolefin products such as polyethylene or polystyrene, and also can produce copolymerization products of ethylene and other α-olefins, such as propylene, butene and hexene. The polymerization conditions are 0-150°C, 0.01-10.0MPa, more preferably 10-90°C, 0.1-5.0MPa.

The polymerization process can adopt solution polymerization, such as slurry polymerization, and the solvent during polymerization can choose organic solvents such as alkanes, aromatic hydrocarbons or halogenated alkanes. The catalyst of the present invention can also be used to produce olefin polymers by gas-phase bulk polymerization.

The transition metal complex catalyst provided by the present invention is a semi-cene catalyst, and a ligand coordinated with the transition metal in the catalyst contains 1 to 2 nitrogen atoms, which can be regarded as replacing cyclopentadiene with nitrogen atoms Ligand groups formed by carbon atoms on the skeleton of its derivatives. The catalyst provided by the invention has higher activity for olefin polymerization and can be polymerized at a lower temperature, and the obtained polymer has higher molecular weight and narrower molecular weight distribution.

The present invention will be described in detail below by examples, but the present invention is not limited thereto.

The operation of preparing the catalyst in the examples was carried out under the protection of high-purity nitrogen using Schlenk equipment. In the examples, Pr represents pyrrolyl, Id represents indolyl, Mz represents imidazolyl, Ai represents 7-azaindolyl, Iz represents indazolyl, Bi benzimidazolyl, Cp represents cyclopentadienyl, Ind represents indenyl, and Flu represents fluorenyl.

Example 1

This example prepares (pyrrolyl)(cyclopentadienyl)titanium dichloride [(Pr)(Cp) _TiCl2 ].

(1) Preparation of pyrrole sodium salt (Pr)Na

Take 2 mmol of sodium hydride (Beijing Zhonglian Chemical Reagent Factory), wash it once with a small amount of dry petroleum ether under the protection of nitrogen, and dry it in vacuum. Add 10 ml of tetrahydrofuran, stir, and cool to 0°C. A solution formed of 2 mmol pyrrole (Fluka, Switzerland) and 5 ml tetrahydrofuran was added dropwise. After stirring at room temperature for 4 hours, the solvent was evaporated under reduced pressure to give pyrrole sodium salt (Pr)Na.

(2) Preparation of catalyst

Add 10 milliliters of dichloromethane to (Pr)Na obtained above, stir to make it uniform, drop 2 millimoles of CpTiCl ₃ (Sweden, ACRS company production) and the yellow solution that 10 milliliters of dichloromethanes form, the mixture becomes Yellow-green, reflux at 40°C for 48 hours. After filtration, the filtrate was concentrated to about 5 mL, and then filtered again, and the solid was washed twice with 10 mL of hexane to obtain 0.36 g of Catalyst A [(Pr)(Cp)TiCl ₂ ] with a yield of 72 wt%.

Elemental analysis results are: C 44.00 wt%, N 6.15 wt%, H 4.11 wt%,

Titanium 19.15% by weight.

Example 2

This example prepares (indolyl)(cyclopentadienyl)titanium dichloride [(Id)(Cp) _TiCl2 ].

Prepare indole sodium salt (Id) Na earlier by the method for example 1, then prepare catalyst. The difference is that the pyrrole in step (1) was replaced by indole (produced by The British Drug Houses LTD., UK), the solvent tetrahydrofuran was replaced by diethyl ether, and the reaction was carried out at room temperature for 6 hours. The reaction time of step (2) was 24 hours, and 0.36 g of catalyst B[(Id)(Cp)TiCl ₂ ] was obtained, with a final yield of 60% by weight.

Elemental analysis results are: C 53.04 wt%, N 4.98 wt%, H 4.12 wt%,

Titanium 14.88% by weight.

Example 3

This example prepares (imidazolyl)(cyclopentadienyl)titanium dichloride [(Mz)(Cp) _TiCl2 ].

Prepare imidazole sodium salt (Mz)Na first by the method for example 1, then prepare catalyst. The difference is that the pyrrole in step (1) was replaced with imidazole (produced by ACRS company in Sweden), and the reaction was carried out at room temperature for 2 hours. The reaction time of step (2) was 12 hours, and 0.38 g of catalyst C[(Mz)(Cp)TiCl ₂ ] was obtained, with a final yield of 75% by weight.

The elemental analysis results are: C 38.17 wt%, N 10.84 wt%, H 2.90 wt%,

Titanium 19.08% by weight.

Example 4

This example prepares (7-azaindolyl)(cyclopentadienyl)titanium dichloride [(Ai)(Cp)TiCl ₂ ].

Get 10 milliliters of newly steamed dichloromethane in a 100 milliliter three-necked bottle, add 1 millimole of 7-azaindole (Sweden, ACRS company production) and 1 millimole of triethylamine (Beijing Lanli Fine Chemicals Co., Ltd. Co., Ltd.), stir well. After cooling to 0°C, a solution formed of 1 mmol CpTiCl ₃ and 10 ml dichloromethane was added dropwise, and reacted at room temperature for 48 hours. After filtration, the filtrate was concentrated to about 5 mL, and then filtered again, and the resulting solid was washed twice with 10 mL of hexane to obtain 0.23 g of catalyst D[(Ai)(Cp)TiCl ₂ ], with a yield of 77% by weight.

Elemental analysis results are: C 47.26 wt%, N 9.37 wt%, H 3.23 wt%,

Titanium 15.21% by weight.

Example 5

This example prepares (indazolyl)(cyclopentadienyl)titanium dichloride [(Iz)(Cp) _TiCl2 ].

Put 20 ml of freshly distilled dichloromethane into a 100 ml three-necked flask, add 1 mmol of indazole (produced by ACRS in Sweden) and 1 mmol of CpTiCl ₃ , and stir to dissolve. After cooling to 0°C, 1 mmol of triethylamine was added dropwise and reacted at room temperature for 48 hours. After filtering, the filtrate was concentrated to about 5 ml, and then filtered again, and the obtained solid was washed twice with 10 ml of hexane to obtain 0.24 g of catalyst E[(Iz)(Cp)TiCl ₂ ] with a yield of 80% by weight.

Elemental analysis results are: C 48.88 wt%, N 9.78 wt%, H 4.25 wt%,

Titanium 15.72% by weight.

Example 6

Catalyst F (benzimidazolyl)(cyclopentadienyl)titanium dichloride [(Bi)(Cp)TiCl ₂ ] was prepared according to the method of Example 5. The difference is to replace indazole with 2 mmol of benzimidazole (Sweden, produced by ACRS company). In addition, the addition of triethylamine and _CpTiCl is 2 mmol, and finally 0.43 gram of catalyst F is obtained. It is 72.2% by weight.

Elemental analysis results are: C 46.85 wt%, N 8.37 wt%, H 4.19 wt%,

Titanium 16.03% by weight.

Example 7

This example prepares (pyrrolyl)(indenyl)titanium dichloride [(Pr)(Ind) _TiCl2 ].

Prepare by the method for example 1, difference is during (2) step reaction with 2 millimoles of indenyl titanium trichloride (Ind) TiCl ₃ (Sweden, ACRS company production) replace CpTiCl ₃ and obtain 0.39 grams Catalyst G [(Pr)(Ind) _TiCl2 ]. The yield was 65.0% by weight.

Elemental analysis results are: C 523.6 wt%, N 4.87 wt%, H 4.03 wt%,

Titanium 14.97% by weight.

Example 8

This example prepares (pyrrolyl)(fluorenyl)titanium dichloride [(Pr)(Flu) _TiCl2 ].

Prepare by the method for example 1, difference is in (2) step reaction with 2 millimoles of fluorenyl titanium trichloride (Flu) TiCl ₃ (Sweden, ACRS company production) replace CpTiCl ₃ obtain 0.44 grams Catalyst H [(Pr)(Flu) _TiCl2 ]. The yield was 63.0% by weight.

Elemental analysis results are: C 57.64 wt%, N 4.34 wt%, H 4.10 wt%,

Titanium 13.14% by weight.

Example 9

This example prepares (pyrrolyl)(indenyl)zirconium dichloride [(Pr)(Ind) _ZrCl2 ].

(1) Preparation of (pyrrolyl) zirconium trichloride (Pr) ZrCl ₃

Under ice-bath conditions, add 2 mmoles of pyrrole to 20 ml of tetrahydrofuran solution dissolved with 2 mmoles of ZrCl ₄ , stir evenly, and then drop in 2 mmoles of triethylamine. React at 25°C for 36 hours, filter, concentrate the filtrate, and filter again. The resulting solid is vacuum-dried and washed twice with 10 ml of hexane to obtain (Pr)ZrCl ₃ .

(2) Preparation of sodium indenyl

Add 2 millimoles of NaH to 10 milliliters of tetrahydrofuran that has been freshly dried, and slowly drop in an equimolar amount of indene under ice-bath conditions. After reacting at room temperature for 6 hours, remove the solvent in the reactant to obtain indenyl sodium [Na(Ind )].

(3) Preparation of catalyst

Take 2 mmol of (Pr)ZrCl ₃ and dissolve it in 20 ml of dry dichloromethane, stir in an ice bath, and slowly add 2 mmol of Na(Ind), gradually return to room temperature, and react for 12 hours. After filtration, the solvent of the filtrate was sucked dry, and the obtained solid was recrystallized with 40 ml of hexane to obtain 0.40 g of catalyst K[(Pr)(Ind)ZrCl ₂ ], with a yield of 58% by weight.

Elemental analysis results are: C 46.03 wt%, N 4.78 wt%, H 3.97 wt%,

Zirconium 25.67% by weight.

Instances 10-18

The following examples carry out the polymerization reaction to prepare polyethylene.

The toluene solution of methylaluminoxane (MAO) used in the examples has a concentration of 10% by weight and is produced by Albemarle Company of the United States. The total amount added during polymerization is based on the content of MAO reaching 7.5×10 ⁻³ moles.

A 250 ml reaction flask equipped with a stirrer was replaced three times with nitrogen and twice with pure ethylene, and ethylene gas was fed into it. Under stirring, 50 ml of dry toluene and the toluene solution of MAO were first added, and then the catalyst and the toluene of MAO were added. The solution is made into a liquid, the catalyst dosage is 1.0×10 ^-5 mol, and the Al/M ratio in the system is 500:1. After constant temperature reaction at 30°C for 0.5 hours, the stirring was stopped, and then the reaction was terminated with excess ethanol and then with a small amount of hydrochloric acid. The reactant was continuously stirred in excess ethanol for 1 hour, filtered, washed with ethanol, water, and ethanol in sequence, and vacuum-dried at 60° C. for 4 hours to obtain a polymer. Catalysts and polymer properties used in the polymerization reactions of each embodiment are shown in Table 1. The weight-average molecular weight Mw and molecular weight distribution _Mw / _{Mn of} the polymer were measured at 135°C by gel chromatography (waters 150C chromatograph) using o-dichlorobenzene as a solvent.

Example 19

In this embodiment, styrene polymerization is carried out to prepare syndiotactic polystyrene.

Reagent-grade styrene was dehydrated with calcium hydride, then distilled under reduced pressure, and stored at low temperature in the dark. The polymerization reaction was carried out under the protection of nitrogen. A 150ml reaction flask was placed in an oil bath at 30°C, and 20ml of toluene, 7ml of MAO toluene solution, 0.01g of catalyst A and 10ml of styrene were added to the reaction flask to make the Al/Ti ratio 500. After reacting for 1 hour, the reaction was terminated with acidified ethanol, the polymer was washed three times with water and ethanol respectively, and dried in vacuum at 70° C. to obtain polystyrene. The activity of the catalyst was 1.2×10 ⁵ g polystyrene/mole titanium·hour. The molecular weight M _w of polystyrene is 3.2×10 ⁴ , the molecular weight distribution M _w /M _n is 4.15, the syndiotacticity is 92.8%, and the melting point T _m is 262.3.

In the above test data, the polystyrene syndiotacticity is determined by the amount of insoluble matter after continuous extraction in boiling acetone for 3 hours. Melting points were determined by differential scanning calorimetry (DSC).

Instance 20

This example carries out the copolymerization reaction of ethylene and 1-hexene.

The 1-hexene was dehydrated with calcium hydride, then distilled under reduced pressure, and stored in the dark. Carry out polymerization reaction by the method for example 10, difference is that 2 milliliters of 1-hexenes are added in the solution of toluene and MAO earlier, then add the toluene solution of catalyst K and MAO, carry out under the condition that Al/Zr is 500:1 Polymerize, collect polymer. The activity of catalyst K is 2.3×10 ⁵ g polymer/mole zirconium·hour, the weight average molecular weight M _w of the polymer is 3.12×10 ⁵ , and the molecular weight distribution M _w /M _n is 2.56.

Table 1 instance number Catalyst number catalyst expression Catalyst activity (g polyethylene/mole M·hour) ^* polymer Molecular weight Mw(×10 ⁴ ) Molecular weight distributionMw/Mn 10 A (Pr)(Cp)TiCl ₂ 1.2×10 ⁵ 34.0 2.19 11 B (Id)(Cp)TiCl ₂ 1.3×10 ⁵ 27.5 2.12 12 C (Mz)(Cp)TiCl ₂ 3.2×10 ⁴ - - 13 D. (Ai)(Cp)TiCl ₂ 2.6×10 ⁴ - - 14 E. (Iz)(Cp)TiCl ₂ 1.2×10 ⁵ 30.0 6.50 15 f (Bi)(Cp)TiCl ₂ 1.4×10 ⁵ 35.8 2.31 16 G (Pr)(Ind)TiCl ₂ 3.2×10 ⁵ 37.2 2.38 17 h (Pr)(Flu)TiCl ₂ 4.3×10 ⁵ 39.5 2.17 18 K (Pr)(Ind)ZrCl ₂ 1.5×10 ⁵ 28.5 2.30

^* M here and M in examples 10-18 refer to titanium or zirconium

Claims (17)

1, a kind of olefin polymerization catalyst, has following general formula expression: In the formula, L is a ligand group containing a diazepine skeleton or an indolyl group containing a nitrogen atom on the benzene ring, and the two nitrogen atoms in the diazepine skeleton are arranged in the meta or ortho position, There are 1 to 4 substituents R ₁ on the five-membered ring of the diazoline skeleton, and the two adjacent substituents on the skeleton can be connected to each other to form a condensed ring with more than two members; Cp is a compound containing a cyclopentadiene skeleton. Ligand group, there are 1 to 5 substituents R ₂ on the skeleton of cyclopentadiene, and two adjacent substituents on the skeleton can be connected to each other to form a condensed ring with more than two members; the R ₁ and R ₂ are respectively selected from hydrogen, C ₁ -C ₁₈ alkyl or perfluoroalkyl, C ₆ -C ₂₄ aralkyl or alkaryl, M is selected from Group IVB metals, X and Y are respectively selected from halogen, C ₁ ~ _C24 alkyl, alkoxy, siloxy or alkaryl. 2. A catalyst according to claim 1, characterized in that M is selected from titanium or zirconium, and X and Y are independently selected from halogen or benzyl. 3. The catalyst according to claim 1, characterized in that R ₁ and R ₂ are respectively selected from hydrogen, C ₁ -C ₆ alkyl, C ₁ -C ₆ perfluoroalkyl, C ₆ -C ₂₄ Aralkyl or alkaryl. 4. The catalyst according to claim 1, characterized in that the ligand L is imidazolyl, pyrazolyl, benzimidazolyl, indazolyl, 7-azaindolyl, or contains a single or multiple substitution The above-mentioned group of the group, the substituent is a C ₁ -C ₆ alkyl group or a perfluoroalkyl group. 5. The catalyst according to any one of claims 1 to 4, characterized in that Cp is cyclopentadienyl, indenyl, fluorenyl, or the above-mentioned groups that are monosubstituted or multisubstituted, and the substituents are C ₁ -C ₈ alkyl or perfluoroalkyl. 6. A method for preparing the catalyst as claimed in claim 1, comprising the steps of: (1) In an ether solvent, equimolar amounts of strongly basic compound and ligand compound HL are fully contacted, and then the solvent is removed to obtain the salt of the ligand compound, (2) In an organic solvent, equimolar amounts of the salt of the above ligand compound and the compound of the general formula CpMX ₂ Y are fully contacted, the solid matter is removed, and the solvent in the obtained liquid is removed to obtain a catalyst. 7. The method according to claim 6, characterized in that the strongly basic compound mentioned in (1) is an alkali metal, an alkali metal alkylate or hydride, or an alkylmagnesium bromide. 8. The method according to claim 7, characterized in that the alkali metal is lithium, sodium or potassium, and the alkyl group in the alkali metal alkylate or alkylmagnesium bromide is selected from C ₁ -C ₈ alkyl groups or aralkyl. 9. The method according to claim 6, characterized in that the ether solvent is diethyl ether or tetrahydrofuran, and the organic solvent is diethyl ether, dichloromethane, chloroform or toluene. 10. A method for preparing the catalyst as claimed in claim 1, comprising the steps of: (1) in an ether solvent, make the strongly basic compound of equimolar amount and cyclopentadiene type ligand compound fully contact reaction, remove solvent to obtain the salt of cyclopentadiene type ligand compound, (2) In an organic solvent, LMX ₃ and the salt of the cyclopentadiene-type ligand compound are fully contacted and reacted under stirring conditions in an equimolar ratio, the solid matter is removed, and the solvent in the obtained liquid is removed to obtain the catalyst. 11. The method according to claim 10, characterized in that the ether solvent is diethyl ether or tetrahydrofuran, and the organic solvent is diethyl ether, dichloromethane, chloroform or toluene. 12. The method according to claim 10, characterized in that said strong basic compound is alkali metal, alkali metal alkylate or hydride, alkylmagnesium bromide. 13. The method according to claim 12, characterized in that the alkali metal is lithium, sodium or potassium, and the alkyl group in the alkali metal alkylate or alkylmagnesium bromide is selected from C ₁ -C ₈ alkyl groups or aralkyl. 14. A method for preparing the catalyst as claimed in claim 1, comprising, in an organic solvent, fully contacting the compound of the general formula CpMX ₂ Y and the ligand compound HL in an equimolar ratio, and then adding three Alkylamine, fully stir the mixture, remove the solid matter, and remove the solvent in the resulting liquid to obtain the catalyst. 15. The method according to claim 14, characterized in that said trialkylamine is triethylamine or tripropylamine, and the organic solvent is ether, methylene chloride or toluene. 16. A method for polymerizing olefins, comprising using the catalyst as claimed in claim 1 as the main catalyst and using aluminoxane, alkylaluminum, alkylaluminum halide or their mixture as a cocatalyst to make α-olefins in the range of 0 to The polymerization reaction is carried out under the conditions of 150°C and 0.01-10.0 MPa, and the Al/M molar ratio is 10-10000 during the reaction. 17. The method according to claim 16, characterized in that said aluminoxane is methylalumoxane, ethylalumoxane or isobutylalumoxane, and the alkylaluminum is trimethylaluminum, trimethylaluminum Ethyl aluminum or triisobutyl aluminum, the alkyl aluminum halide is diethyl aluminum monochloride or diethyl aluminum sesquimonochloride; and the molar ratio of Al/M is 50-5000 during the reaction.