CN1160380C - Method for synthesizing supported metallocene catalyst - Google Patents

Abstract

The invention discloses a method for synthesizing a supported metallocene catalyst. The carrier is mixed with a IVB group transition metal halide in a solvent under normal pressure, and then directly reacted with a ligand anion. In the invention, the synthesis and loading of the metallocene catalyst are completed in one step, the process steps are simple, and it is used for olefin polymerization in combination with a co-catalyst, and the activity of the catalyst meets the requirements for use.

Description

A method for synthesizing supported metallocene catalysts

technical field

The invention relates to a synthesis method of a metallocene catalyst, in particular to a synthesis method of a supported metallocene catalyst for olefin polymerization.

Background technique

Metallocene catalyst systems for polymerization are mainly divided into two categories: homogeneous type and supported type. Homogeneous metallocene catalytic systems have many problems such as poor polymer morphology and high cocatalyst dosage in industrial applications. Therefore, supported metallocene catalytic systems have become the main direction of research. At present, the most common preparation method is to prepare the metallocene catalyst first, and then react with the cocatalyst alkyl aluminoxane and silica gel to form the metallocene catalyst system. Among them, the metallocene catalyst is prepared by using at least one cyclopentadiene or its derivatives as a ligand, reacting with transition metal halides after negative ionization and purifying. The related patents include WO 9632 423, DE4426 122, US5006,500, and EP727 ,443 et al. However, since the reaction between the ligand and the halide is a liquid-solid reaction, the transition metal halide can only be complexed with a small amount of solvent, the yield of the catalyst polymerization is not high, and the purification of the reactant is complicated. Another promising method for the preparation of metallocene catalysts is that the transition metal element is first contacted with the carrier, and then reacted with the lithium salt of the ligand, typically as described in patent EP708116, which first gasifies zirconium tetrachloride (ZrCl ₄ ) Contact and support the carrier at a temperature of 160°C to 450°C, and then react the loaded ZrCl ₄ with the lithium salt of the ligand, and cooperate with a co-catalyst for polymerization. The problem is that the loading process requires high temperature and high vacuum, which is not suitable for industrial production.

Contents of the invention

The present invention proposes a method for synthesizing supported metallocene catalysts under normal pressure

The preparation process of metallocene catalyst is as follows:

a) Mix the carrier with the solvent, then add the transition metal halide at 20-150°C, preferably at 40-120°C, and remove the solvent after stirring to obtain solid A;

b) Select the ligand and dissolve it in a solvent, add a proton donor under the protection of an inert gas, react at -100-50°C, preferably at -78-25°C, and stir for 4-24 hours, preferably for After 8-12 hours, solution B was obtained:

c) Add solid A and B solutions into the solvent at a ratio of 1:1 molar ratio of titanium (or zirconium or hafnium) to the ligand, mix and stir, and react at room temperature for 4-20 hours, preferably 6-12 hours , extract the solvent and wash to obtain a metallocene catalyst.

The carrier is selected from one or more of silica gel, aluminum oxide, magnesium chloride, lithium chloride, clay, etc., and silica gel is more commonly used. The amount of carrier used should ensure that the central atom content of the metallocene compound in the final complex is 0.01%-50%, preferably 0.1%-10%.

Proton donors include organometallic compounds, metal hydrides or alkali metals, typically alkyllithium, preferably butyllithium.

Ligands can be bridged or unbridged, including cyclopentadienyl and its derivatives, indenyl, fluorenyl, substituted indenyl or fluorenyl, dimethyl carbon bridged cyclopentadienyl indenyl, Dimethylsilyl-bridged cyclopentadienylindenyl.

In the present invention, the synthesis and loading of the metallocene catalyst are completed in one step, the preparation steps are simple, the process conditions are easier to realize, and the catalyst is used for polymerization in cooperation with the co-catalyst, and the activity of the catalyst meets the requirements for use.

Detailed ways

Example 1, isopropyl dichloride (9-fluorene) (1-cyclopentadienyl) zirconium supported catalyst

a) Mix 113 grams of silica gel with 200 ml of tetrahydrofuran in a Schlenk flask, then add 5.8 grams of zirconium tetrachloride (ZrCl ₄ ), stir vigorously at room temperature for 4 hrs, and remove tetrahydrofuran with vacuum to obtain solid A;

b), under stirring, 0.05mol (1.6M) butyllithium was added to 200ml of tetrahydrofuran solution in which 6.8 grams of isopropyl (9-fluorene) (1-cyclopentadiene) ligand was dissolved, and the solution was at room temperature Stir for about 12hrs to obtain solution B;

c) Add solid A to solution B, stir vigorously, and stir the resulting dark red solution for another 12 hrs. After all the solvents were removed under vacuum, 120.6 grams of red solid was obtained, which was made into the catalyst of this patent, and then used in polymerization reaction with cocatalyst methylaluminoxane (MAO). The results are shown in Table 2.

Example 2, isopropyl dichloride (9-fluorene) (1-cyclopentadienyl) hafnium supported catalyst

The ZrCl ₄ ligand was replaced with hafnium tetrachloride (HfCl ₄ ), and the preparation method was the same as in Example 1. The results of the prepared catalyst are shown in Tables 1 and 2.

Embodiment 3, dibutyl cyclopentadienyl zirconium dichloride supported catalyst

Using butylcyclopentadiene as a ligand to replace isopropyl (9-fluorene) (1-cyclopentadiene), the preparation method is the same as in Example 1, and the results of the prepared catalyst are shown in Tables 1 and 2.

Example 4, dimethyl silicon bridged (cyclopentadienyl) (indenyl) zirconium dichloride supported catalyst

With dimethyl silicon bridged indenyl cyclopentadienyl substituted isopropyl (9-fluorene) (1-cyclopentadiene) as a ligand, the preparation method is the same as in Example 1, and the results of the prepared catalyst are shown in Table 1 ,2.

Embodiment 5, dichlorozirconocene supported catalyst

Using cyclopentadiene as a ligand to replace isopropyl (9-fluorene) (1-cyclopentadiene), the preparation method is the same as in Example 1, and the results of the prepared catalyst are shown in Tables 1 and 2.

Embodiment 6, dichlorination 1, 2-ethylene bis(1-indene) zirconium loaded catalyst

With 2-ethylene bis(1-indene) substituted isopropyl (9-fluorene) (1-cyclopentadiene) as a ligand, the preparation method is the same as in Example 1, and the prepared catalyst results are shown in Tables 1 and 2. .

Embodiment 7, cyclopentadienyl indenyl zirconium dichloride supported catalyst

With aluminum oxide as a carrier, cyclopentadiene and indene substituted isopropyl (9-fluorene) (1-cyclopentadiene) as a ligand, the preparation method is the same as in Example 1, and the results of the prepared catalyst are shown in Table 1 ,2.

Embodiment 8, two (tetramethylcyclopentadienyl) zirconium dichloride supported catalysts

Using tetramethylcyclopentadiene as a ligand to replace isopropyl (9-fluorene) (1-cyclopentadiene), the preparation method is the same as in Example 1, and the results of the prepared catalyst are shown in Tables 1 and 2.

Table 1 Preparation of metallocene catalysts catalyst carrier metal halide Ligand The content of Zr(Hf) in the catalyst % 1 Silica gel _ZrCl4 Isopropyl(9-fluorene)(1-cyclopentadiene) 1.87 2 Silica gel _HfCl4 Isopropyl(9-fluorene)(1-cyclopentadiene) 1.3 3 Silica gel _ZrCl4 Butylcyclopentadiene 1.85 4 Silica gel _ZrCl4 Dimethylsilyl bridged indenylcyclopentadienyl 1.85 5 Silica gel _ZrCl4 Cyclopentadiene 1.81 6 Silica gel _ZrCl4 2-Ethylenebis(1-indene) 1.78 7 Aluminum oxide _ZrCl4 cyclopentadiene and indene 1.10 8 Silica gel _ZrCl4 Tetramethylcyclopentadiene 1.82

Table 2 Polymerization test results catalyst aggregation condition Polymerization activity monomer aggregation method temperature °C Pressure KPa time hr Al/Zr(Hf ×10 ⁷ g/(mol·h) 1 Propylene ontology 80 0.8 4 50 1.10 2 Propylene ontology 80 0.8 4 50 0.5 3 Propylene ontology 80 0.8 4 0.99 4 Propylene ontology 30 0.8 4 150 1.87 5 ^* Vinyl slurry 60 0.6 4 100 2.71 6 Ethylene, 15% hexene slurry 60 0.6 4 100 3.11 7 Vinyl slurry 60 0.8 4 200 1.10 8 Vinyl slurry 70 0.7 4 200 1.20

^* Except that the cocatalyst in Example 5 is [Ph ₃ C]B(C ₆ F ₅ ) ₄ , the metallocene catalysts are added with cocatalyst methylaluminoxane during polymerization.

Claims (8)

1. the method for a synthetic carried metallocene catalyst, carry out according to the following steps:

A) carrier is dissolved in the solvent, adds transition metal halide down at 20-150 ℃, extracts solvent after the stirring, gets solid A;

B) use the dissolution with solvents part, under inert gas protection, add the proton donor, be reflected at-100-50 ℃ carries out, stirs and obtained solution B in 4-24 hour;

C) solid A is joined with 1: 1 the ratio of mole number of part in transition metal with solution B mix stirring in the solvent, reacted at normal temperatures 4-20 hour, extract solvent, make metallocene catalyst after the washing.

2. the synthetic method of catalyzer according to claim 1 is characterized in that the usage quantity of carrier should guarantee to contain in the final title complex central atom content of metallocene compound at 0.01%-50%.

3. the synthetic method of catalyzer according to claim 1 is characterized in that the usage quantity of carrier should guarantee to contain in the final title complex central atom content of metallocene compound at 0.1%-10%.

4. the synthetic method of catalyzer according to claim 1 is characterized in that carrier is a silica gel.

5. the synthetic method of catalyzer according to claim 1 is characterized in that transition metal is selected from titanium, zirconium or hafnium.

6. the synthetic method of catalyzer according to claim 1 is characterized in that part is bridging type or non-bridging type.

7. the synthetic method of catalyzer according to claim 1 is characterized in that part is the indenes of cyclopentadienyl and derivative thereof, indenyl, fluorenyl, replacement or fluorenyl, dimethyl carbon bridged cyclopentadienyl indenyl, dimethyl-silicon bridged cyclopentadienyl indenyl.

8. the synthetic method of catalyzer according to claim 1 is characterized in that the proton donor is a butyllithium.