CN116789711A - A kind of hafnium/zirconium complex containing flexible groups and its preparation method - Google Patents

Abstract

The invention discloses a preparation method of a hafnium/zirconium complex containing a flexible group, which is produced by synthesizing a ligand containing a flexible group, and then using the flexible ligand to coordinate with the mixed hafnium/zirconium tetrachloride. The structural formula of the hafnium/zirconium complex containing flexible groups is as follows: In the formula: R is One of them; Ln is Zr or Hf; n=1, 2 or 3; X is .

Description

A kind of hafnium/zirconium complex containing flexible groups and its preparation method

Technical field

The invention belongs to the field of cene mixed hafnium/zirconium metal catalysts, and specifically relates to a cene mixed hafnium/zirconium complex containing a flexible group and a preparation method thereof.

Background technique

As a new generation of olefin polymerization catalysts, hafnium/zirconium complexes will have huge development potential. The hafnium/zirconium complexes are combined with alkylaluminoxane to form a hafnium/zirconium catalyst system. Metallocene catalysts belong to the category of metal-organic chemistry. Metal-organic chemistry is a relatively complex interdisciplinary subject that is involved in the fields of medicine, biology, life sciences, and materials, and has broad development prospects. Due to the great application value of metallocene catalysts in olefin polymerization, it has become one of the most popular research fields in the world in the past thirty years.

The molecular structure of metallocene complexes is relatively clear, the reaction mechanism is relatively easy to reason, and related products are easy to scale up and produce. These characteristics are of great significance to the theoretical research and industrial production of the polyolefin industry. They also provide opportunities for future catalyst modification and It provides theoretical support and development ideas to develop new catalysts with higher performance.

Contents of the invention

In order to achieve the above object, the present invention provides a flexible group-containing cyclopentadiene mixed hafnium/zirconium complex and a preparation method thereof. The cyclopentadiene derivative containing a flexible group is used as the ligand and the chlorinated mixed hafnium/zirconium The structural formula of the complex obtained by coordination is as follows:

In the formula: R is one of;

Ln is Zr or Hf; n=1, 2 or 3; X is .

Preferably, R in the formula is preferably: .

Preferably, X in the formula is hexamethyldisilazanyl.

The preparation reaction mechanism of the aforementioned flexible group-containing hafnium/zirconium complex is as follows:

;

In the formula: R is one of;

Ln is Zr or Hf; n=1, 2 or 3; X is .

The preparation method of the aforementioned hafnium/zirconium complex containing flexible groups includes the following steps:

1) The preparation process is carried out under nitrogen conditions;

2) Place LnX ₄ in anhydrous tetrahydrofuran, add the ligand Cp-R containing a flexible group at -20~25°C, stir and react for 2-6 hours, and the reaction is completed;

3) After the reaction is completed, filter to obtain a colorless clear solution, drain the solvent with an oil pump, and then recrystallize with petroleum ether and toluene to obtain the complex.

The aforementioned hafnium/zirconium complex containing a flexible group can be used in the preparation of a new generation of hafnium/zirconium catalyst for olefin polymerization.

Beneficial effects of the present invention: the flexible group-containing hafnium/zirconium complex compound of the present invention has a relatively clear molecular structure, a clear reaction mechanism, and is easy to scale up production, and can be applied to the preparation of a new generation of olefin polymerization hafnium/zirconium catalysts , has good application and economic value.

Description of the drawings

Figure 1 is the structural formula of the flexible group-containing zirconium compound prepared in Example 1 of the present invention;

Figure 2 is the structural formula of the hafnium compound containing flexible groups prepared in Example 2 of the present invention.

Detailed ways

The present invention is specifically described below through examples:

Example 1

Under a nitrogen atmosphere, weigh 2.055 g (0.015 mol) of the ligand CH ₃ OCH ₂ CH ₂ CH ₂ -CP and add it dropwise to a 100 mL three-necked flask under nitrogen conditions. Add 25 mL of dry THF and mix in an ice-salt bath. Lower the temperature to -10°C and keep it warm for 15 minutes. Weigh 2.862 g (0.005 mol) of zirconium hexamethyldisilazane ZrX ₄ and add it to the flask. After the temperature returns to room temperature, continue the reaction for 2 hours.

THF is removed under vacuum conditions, toluene is recrystallized, and the crude product is precipitated by low-temperature freezing. The product is obtained by filtration, and the crystals are precipitated by freezing to obtain the target product. Its structural formula is shown in Figure 1. After testing, the yield of the flexible group-containing zirconium compound prepared in this example was 81%. ¹ H NMR (400 MHz, Chloroform- d ) δ 6.34 (s, 2H), 6.24 (s,2H), 3.33 (t, J = 6.3 Hz, 2H), 3.32 (s, 3H), 2.71 (s, 2H ), 1.82 (s, 2H), 0.08(s, 6H). ¹³ C NMR (101 MHz, Chloroform- d ) δ 135.12, 116.38, 112.71, 72.67,58.30, 32.45, 26.32, 5.23. FT-IR(KBr, ν,cm ^-1 ); 3103, 3084, 2977, 2930, 2745,1650, 1483, 1451, 1388, 1287, 1115, 1045, 877, 826.

Example 2

Under a nitrogen atmosphere, weigh 1.78 g (0.01 mol) of the ligand CH ₃ CH ₂ CH ₂ CH ₂ C(CH ₂ CH ₃ )CH ₂ -Cp and drop it into a 100 mL three-necked flask under nitrogen conditions, and add 25 mL. Dry THF, cool down to -5°C in an ice-salt bath and keep it warm for 15 minutes. Weigh 3.298 g (0.005 mol) of hexamethyldisilazane hafnium HfX ₄ into the flask. After the temperature returns to room temperature, continue Reaction 2 h.

THF is removed under vacuum conditions, toluene is recrystallized, and the crude product is precipitated by freezing at low temperature. The product is obtained by filtration, and crystals are precipitated by freezing to obtain the target product, whose structural formula is shown in Figure 2. After testing, the yield of the flexible group-containing hafnium compound prepared in this example was 79%. ¹ H NMR (400 MHz, Chloroform- d ) δ 6.42 (d, J = 39.3 Hz,4H), 2.44 (s, 2H), 1.63 (s, 1H), 1.27 (s, 8H), 0.88 (s, 6H ), 0.08 (s, 18H). ¹³ C NMR (101 MHz, Chloroform- d ) δ 133.45, 132.74, 119.42, 115.73, 116.63,44.35, 35.31, 27.98, 26.25, 23.52, 14.15, 1 1.12, 5.22. FT-IR (KBr,ν,cm ^-1 ); 3110,2984, 2922, 2812, 1502, 1491, 1300, 1250, 1051, 921, 811.

Claims (5)

1. A flexible group-containing hafnium/zirconium compound, which is characterized by: expressed by the following general formula: In the formula: R is one of; Ln is Zr or Hf; n=1, 2 or 3; X is . 2. The flexible group-containing hafnium/zirconium complex compound according to claim 1, characterized in that: R in the formula is or/> . 3. The flexible group-containing hafnium/zirconium complex according to claim 1, characterized in that: in the formula, X is a hexamethyldisilazanyl group. 4. The preparation method of the flexible group-containing hafnium/zirconium complex according to any one of claims 1-3, characterized in that the steps are as follows: 1) The preparation process is carried out under nitrogen conditions; 2) Place LnX ₄ in anhydrous tetrahydrofuran, add the ligand Cp-R containing a flexible group at -20 to 25°C, and stir for 2 to 6 hours. The reaction is completed; 3) After the reaction is completed, filter to obtain a colorless clear solution, drain the solvent with an oil pump, and then recrystallize with petroleum ether and toluene to obtain the complex. 5. The application of flexible group-containing hafnium/zirconium complexes according to claim 1: characterized in that it is applied to the preparation of a new generation of olefin polymerization hafnium/zirconium catalysts.