阅读说明：本技术 用于全氟聚醚聚合反应用的催化剂的制备方法 (Preparation method of catalyst for polymerization reaction of perfluoropolyether ) 是由 王汉利 张鹏 张敬 刘钊 刘起 于 2020-11-25 设计创作，主要内容包括：本发明属于全氟聚醚聚合技术领域,具体涉及一种用于全氟聚醚聚合反应用的催化剂的制备方法,包括以下步骤：(1)将Ni(cod)-2与PQ-3(Q＝Me,Et,～iPr)在溶剂中混合反应,制得原料B；(2)得到原料B后,将原料B与原料A在溶剂中进行C-F键的活化反应,得到用于全氟聚醚聚合反应用的催化剂。本发明通过筛选特定的配体,制备得到含有金属氟键的有机金属配合物,并将此配合物作为催化剂应用到了K型全氟聚醚聚合中,在与传统无机氟化物对比下,在少量催化剂的情况下,可以明显提高全氟聚醚油的聚合度,较少溶剂使用量,从而有效较低聚合反应的成本,同时本发明制备方法步骤简单,条件要求不苛刻,目标产物收率高。(The invention belongs to the technical field of perfluoropolyether polymerization, and particularly relates to a preparation method of a catalyst for perfluoropolyether polymerization reaction, which comprises the following steps: (1) mixing Ni (cod) 2 And PQ 3 (Q＝Me，Et， i Pr) is mixed and reacted in a solvent to prepare a raw material B; (2) and after the raw material B is obtained, carrying out C-F bond activation reaction on the raw material B and the raw material A in a solvent to obtain the catalyst for the polymerization reaction of the perfluoropolyether. The invention obtains the organic metal complex containing metal fluorine bond by screening specific ligand, and applies the complex as catalyst to K-type perfluoropolyether polymerization, under the condition of a small amount of catalyst, compared with the traditional inorganic fluoride, the invention can obviously improve the polymerization degree of perfluoropolyether oil and reduce the using amount of solvent, thereby effectively reducing the cost of polymerization reaction, and simultaneously, the preparation method has simple steps, non-rigorous condition requirements and high yield of target product.)

1. A preparation method of a catalyst for polymerization reaction of perfluoropolyether is characterized by comprising the following steps: the method comprises the following steps:

(1) mixing Ni (cod)₂And PQ₃(Q＝Me，Et，ⁱPr) is mixed and reacted in a solvent to prepare a raw material B;

(2) carrying out C-F bond activation reaction on the raw material B and the raw material A in a solvent to obtain a catalyst for polymerization reaction of perfluoropolyether;

wherein:

the structural formula (II) of the starting material B is selected from:

Ni(PMe₃)₄ (II-1)

Ni(PEt₃)₄ (II-2)

Ni(PⁱPr₃)₄ (II-1)

the structural formula (I) of the raw material A is as follows:

the catalyst has the structural formula (III):

(III):R＝PMe₃，PEt₃，PⁱPr₃。

2. the method for producing a catalyst for polymerization of perfluoropolyether according to claim 1, characterized in that: the solvent in the step (1) and the step (2) is an aprotic solvent.

3. The method for producing a catalyst for polymerization of perfluoropolyether according to claim 1, characterized in that: ni (cod) described in step (1)₂And PQ₃The molar ratio of (A) to (B) is 12-15: 25 to 32.

4. The method for producing a catalyst for polymerization of perfluoropolyether according to claim 1, characterized in that: the mixing temperature in the step (1) is 20-80 ℃, and the mixing reaction time is 4-10 h.

5. The method for producing a catalyst for polymerization of perfluoropolyether according to claim 1, characterized in that: ni (cod) described in step (1)₂And PQ₃The ratio of the total amount of the substances to the amount of the solvent is 71-90 mmol: 50-100 mL.

6. The method for producing a catalyst for polymerization of perfluoropolyether according to claim 1, characterized in that: and (2) carrying out suction filtration on the precipitate in the reaction liquid obtained in the step (1), extracting the precipitated solid by adopting n-pentane, and then recrystallizing the extraction liquid to obtain the raw material B.

7. The method for producing a catalyst for polymerization of perfluoropolyether according to claim 1, characterized in that: the activation reaction process in the step (2) is as follows: and (2) pumping a solvent into the raw material B and the raw material A obtained in the step (1) by using a needle cylinder under the condition of protective gas, carrying out C-F bond activation reaction, carrying out suction filtration on a precipitate in the obtained reactant, washing the precipitated solid by using n-pentane, and drying the washed solid to obtain the catalyst for the polymerization reaction of the perfluoropolyether.

8. The method for producing a catalyst for polymerization of perfluoropolyether according to claim 1, characterized in that: in the step (2), the molar ratio of the raw material B to the raw material A is 8-9: 10 to 12.

9. The method for producing a catalyst for polymerization of perfluoropolyether according to claim 1, characterized in that: the ratio of the total amount of the raw material B and the raw material A in the step (2) to the amount of the solvent is 40-60 mmol: 10-60 mL.

10. The method for producing a catalyst for polymerization of perfluoropolyether according to claim 1, characterized in that: the reaction temperature in the step (2) is 25-40 ℃, and the reaction time is 6-12 h.

Technical Field

The invention belongs to the technical field of perfluoropolyether polymerization, and particularly relates to a preparation method of a catalyst for perfluoropolyether polymerization.

Background

PerfluoroPolyethers (PFPE, english name perfluoro polymers) are high molecular weight polymers that are colorless, odorless, transparent, oily liquids at room temperature. The perfluoropolyether has the characteristics of heat resistance, oxidation resistance, radiation resistance, corrosion resistance, non-combustion and the like, so that the perfluoropolyether is an extremely reliable lubricant under severe conditions. Since the 60 s of the 20 th century, researchers at home and abroad have conducted very extensive research on perfluoropolyethers, and nowadays, perfluoropolyethers are widely applied to the fields of chemical industry, electronics, electrical appliances, machinery, nuclear industry, aerospace and the like.

Compared with hydrocarbon lubricants, the PFPE lubricant has basically similar molecular structure, but fluorine atoms replace hydrogen atoms in the molecule, so that C-H bonds in hydrocarbons are replaced by stronger C-F bonds, and the existence of strong covalent bonds of C-O and C-C and the characteristic of neutrality of PFPE molecules enable the PFPE to have higher thermal stability and oxidation stability and good chemical inertness and insulating property. PFPEs with higher molecular weights also have low volatility, a wider liquid temperature range and excellent viscosity-temperature characteristics. Compared with chlorofluorocarbon lubricants, the perfluoropolyether lubricant has wider application temperature range, avoids the defects that chlorofluorocarbons are easy to evaporate at high temperature and become sticky and thick at low temperature, and also avoids the defect that the chlorofluorocarbons contain chlorine to corrode a bearing when the lubricant is pressed in the use of a high-load bearing. Compared with the fluorine-silicon lubricant, the viscosity and the evaporation rate of the perfluoropolyether lubricant are equivalent to those of the fluorine-silicon lubricant, but the lubricating effect and the chemical stability of the perfluoropolyether lubricant are much better than those of the fluorine-silicon lubricant. In addition, the main physicochemical properties of the polymer also include: shear stability, biological inertness, low surface energy, good lubricity and compatibility with plastics, metals and elastomers, etc. PFPE has a good balance of properties, making it an extremely reliable lubricant in harsh environments.

The molecular structure of the K type perfluoropolyether is as follows:

wherein for the K-type perfluoropolyether, the structure is shown above. Originally invented by 3M corporation in the last 60 th centuryAfter more than 50 years of development, a series of perfluoropolyether oil grades applied to different fields are formed; in addition, in the polymerization process, various researchers in the world have conducted a great deal of systematic studies, particularly, a series of screens for catalysts, species and systems. Heinrich et al uses AgNO₃As a catalyst, oligomers of HFPO were produced in acetonitrile with 86% yield of dimers and 3% yield of trimers. But due to AgNO₃The method has certain limitations because of its photosensitivity and easy generation of nitrous acid. Germany G.K uhne used CuCl/CuC1₂The acrylonitrile catalytic system oligomerizes HFPO in acetonitrile solvent, and the yield of the dimer can reach 82%. However, acrylonitrile in this method is suspected of being carcinogenic. AKIRA et al, Yoshida, Japan, prepare HFPO polymers in a protic solvent using CsF as a catalyst, and the reaction temperature is maintained at-20 ℃. However, the water absorption of cesium fluoride makes the experimental operation difficult, and it is expensive and not suitable for industrial application. Martini adopts bis-dialkylamino difluoromethane as catalyst and diethylene glycol dimethyl ether as solvent to carry out oligomerization reaction on HFPO, and the yields of trimer and tetramer in the final product are respectively 59% and 45%. Alfurdride et al use a catalyst system to effect oligomerization of HFPO. The system is comprised of a mixture of an alkali metal fluoride, a dinitrile compound and a polyglycolyme ether. When the concentration of the polyether in the catalyst system is larger, the average degree of polymerization and the reaction speed are improved, so that the polymer with the trimer as the main component can be obtained by using polyether with lower concentration intentionally, and the polymer with the tetramer as the main component can be obtained by using polyether with higher concentration. The catalyst system can simultaneously achieve narrow molecular weight distribution. Segmented friendle, male margarita, etc. studied the self-polymerization of perfluoropropylene oxide catalyzed by KF and the bifunctional anionic polymerization of perfluoropentane (or hexane) diacyl fluoride. The activity of KF perfluoropropylene oxide self-polymerization under normal pressure is found to be much smaller than that of CsF catalytic activity reported in the literature, the conversion rate of the reaction is low, and the molecular weight of the generated perfluoropolyether acyl fluoride is small and is only a dimer generally. Hintzer et al also use KF as catalyst, under certain pressure and temperature, to organic protic solvent (such as diglyme, tetrahydrofuran, and hexa-dioxygen)Ring) and introducing a mixed gas of HFPO and HFP (the mass ratio of 4-0.05) to polymerize.

The K-type perfluoropolyether obtained by the polymerization method disclosed in the above document is mainly composed of potassium fluoride and cesium fluoride as alkali metal fluorides, and the solvent used is a polar aprotic solvent, which is poor in solubility of the alkali metal fluoride in the solvent, and this results in the need to use a large amount of solvent to dissolve the catalyst, leading to an increase in polymerization cost and difficulty in solvent recovery. Further, potassium fluoride has low catalytic activity and cannot give perfluoropolyether having a high polymerization degree, and cesium fluoride has a higher catalytic activity than potassium fluoride, but is expensive and has a high hygroscopicity, which makes industrial scale-up difficult.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the preparation method of the catalyst for polymerization of the perfluoropolyether is provided, the obtained metal nickel complex is used as the catalyst to be applied to the polymerization of the K-type perfluoropolyether, the polymerization degree of the perfluoropolyether can be obviously improved under the condition of the same dosage compared with the traditional inorganic catalyst, and in addition, the better effects are achieved in the aspects of improving the yield, reducing the dosage of the used solvent and the like, so that the production cost of the K-type perfluoropolyether is further reduced.

The preparation method of the catalyst for polymerization reaction of perfluoropolyether comprises the following steps:

(1) under the protection of inert gas, adding Ni (cod)₂And PQ₃(Q＝Me，Et，ⁱPr) is mixed and reacted in a solvent to prepare a raw material B;

(2) after the raw material B is obtained, carrying out C-F bond activation reaction on the raw material B and the raw material A in a solvent to obtain a catalyst for polymerization reaction of perfluoropolyether;

wherein:

the structural formula (II) of the starting material B is selected from:

Ni(PMe₃)₄ (II-1)

Ni(PEt₃)₄ (II-2)

Ni(PⁱPr₃)₄ (II-1)

the structural formula (I) of the raw material A is as follows:

the catalyst has the structural formula (III):

(III):R＝PMe₃，PEt₃，PⁱPr₃。

the structural formula (III) of the catalyst is selected from:

wherein:

the solvent used in step (1) and step (2) is an aprotic solvent, preferably THF (tetrahydrofuran), and more preferably dehydrated anhydrous THF, which enhances the solubility of the catalyst. The inert gas is preferably high purity nitrogen.

Ni (cod) described in step (1)₂And PQ₃The molar ratio of (A) to (B) is 12-15: 25-32, preferably 13.5: 28.4.

the mixing temperature in the step (1) is 20-80 ℃, preferably 45 or 60 ℃, and the mixing reaction time is 4-10 hours, preferably 6 hours.

Ni (cod) described in step (1)₂And PQ₃The ratio of the total amount of the substances to the amount of the solvent is 71-90 mmol: 50-100 mL, preferably 84.6 mmol: 100 mL.

In step (1), Ni (cod)₂And PQ₃(Q＝Me，Et，ⁱPr) after the reaction, cooling the product solution after the reaction, wherein the temperature of the cooled product solution is room temperature, and the cooled solution can bePrecipitating, carrying out suction filtration on the obtained precipitate, extracting the precipitated solid with n-pentane, and recrystallizing the extract to obtain the raw material B.

The activation reaction process in the step (2) is as follows: and (2) under the condition of protective gas, injecting a solvent into the raw material B and the raw material A obtained in the step (1) by using a needle cylinder, and carrying out C-F bond activation reaction to obtain the catalyst for the polymerization reaction of the perfluoropolyether.

In the step (2), the molar ratio of the raw material B to the raw material A is 8-9: 10-12, preferably 8.4: 11.2.

the ratio of the total amount of the raw material B and the raw material A in the step (2) to the amount of the solvent is 40-60 mmol: 10-60 mL, preferably 49.06 mmol: 60 mL.

The reaction temperature in the step (2) is 25-40 ℃, preferably 40 ℃, and the reaction time is 6-12 h, preferably 8 h.

And (3) carrying out suction filtration on the obtained precipitate in the reactant in the step (2), then washing the precipitated solid by adopting n-pentane, and drying the washed solid to obtain the nickel metal complex with the structure shown in the formula (III) which is used as the catalyst for the polymerization reaction of the perfluoropolyether. The steps of suction filtration and recrystallization are not particularly limited in the present invention, and the steps of suction filtration, n-pentane and drying, which are well known to those skilled in the art, may be employed.

Compared with the prior art, the invention has the following beneficial effects:

the invention obtains the organic metal complex containing metal fluorine bond by screening specific ligand, and applies the complex as catalyst to K-type perfluoropolyether polymerization, under the condition of a small amount of catalyst, the invention can obviously improve the polymerization degree of perfluoropolyether oil and reduce the solvent consumption, thereby effectively reducing the polymerization reaction cost. Meanwhile, the preparation method has simple steps, non-harsh requirements on conditions and high yield of the target product.

Detailed Description

The present invention will be further described with reference to the following examples.

All the raw materials used in the examples are commercially available unless otherwise specified.

Example 1

The structural formula (I) of the raw material A is as follows:

the raw material B has a structure represented by the formula (II-1), Ni (PMe)₃)₄；

The catalyst has a structure represented by formula (III-1):

the preparation method of the catalyst for polymerization reaction of perfluoropolyether comprises the following steps:

step 1: weighing raw materials Ni (cod) under a nitrogen protection system₂(47.8mmol，13.15g)，PMe₃(trimethylphosphine) (100.33mmol, 7.63g) was added to the reaction, 175mL of THF solution was added, the reaction was allowed to react at 45 ℃ for 6h under nitrogen, then cooled to room temperature, the solvent THF was drained, extracted with n-pentane, and the extracts were placed in a 0 ℃ refrigerator to give yellow needle crystals as starting material B (7.29g, 42% yield).

Step 2: weighing raw material B (15.43mmol, 5.60g), adding raw material A (19.29mmol, 3.26g), adding THF 50mL into the system, reacting at 25 ℃ for 10h under the protection of nitrogen, filtering the solvent with suction, washing with n-pentane, and putting the residual solid after washing into a vacuum drying oven for drying to obtain a yellow powdery nickel metal complex catalyst (3.40g, yield 58%) for perfluoropolyether polymerization reaction, wherein the yellow powdery nickel metal complex catalyst has a structure shown in formula (III-1).

HPLC purity: 99.2 percent. Mass spectrum: calculated value 379.90; the test value was 380.04. Elemental analysis: the calculated values are: c: 34.78 percent; h: 4.78 percent; n: 3.69 percent; the test values are: c: 34.97 percent; h: 4.91 percent; n: 3.56 percent.

Example 2

Feed a was the same as in example 1:

the raw material B has a structure represented by the formula (II-1), Ni (PMe)₃)₄；

The catalyst has a structure represented by formula (III-1):

the preparation method of the catalyst for polymerization reaction of perfluoropolyether comprises the following steps:

step 1: weighing raw materials Ni (cod) under a nitrogen protection system₂(114.7mmol，31.55g)，PMe₃(246.61mmol, 18.76g) was added to the reaction system, 450mL of THF solution was added and the reaction was carried out at 60 ℃ for 5h under nitrogen, then cooled to room temperature, the solvent THF was drained and extracted with n-pentane, and the extract was placed in a 0 ℃ refrigerator to give yellow needle-like crystals as starting material B (25.81, 62% yield).

Step 2: weighing raw material B (42.94mmol, 15.59g), adding raw material A (53.68mmol, 9.07g), adding THF (120 mL) into the system, reacting at 25 ℃ for 10h under the protection of nitrogen, filtering the solvent with suction, washing with n-pentane, and putting the residual solid after washing into a vacuum drying oven for drying to obtain a yellow powdery nickel metal complex catalyst (10.44g, the yield is 64%) for the polymerization reaction of perfluoropolyether, wherein the yellow powdery nickel metal complex catalyst has the structure shown in formula (III-1).

HPLC purity: 98.7 percent. Mass spectrum: calculated value 379.90; the test value was 379.76. Elemental analysis: the calculated values are: c: 34.78 percent; h: 4.78 percent; n: 3.69 percent; the test values are: c: 34.61 percent; h: 4.69 percent; n: 3.82 percent.

Example 3

The starting material A was the same as in example 1;

the raw material B has a structure represented by the formula (II-2), Ni (PEt)₃)₄；

The catalyst has a structure represented by formula (III-2):

the preparation method of the catalyst for polymerization reaction of perfluoropolyether comprises the following steps:

step 1: weighing raw materials Ni (cod) under a nitrogen protection system₂(24.8mmol，6.82g)，PEt₃(triethylphosphine) (53.29mmol, 6.30g) was added to the reaction, 90mL of THF solution was added, the reaction was allowed to react at 45 ℃ for 6h under nitrogen, then cooled to room temperature, the solvent THF was drained, extraction was performed with n-pentane, and the extract was placed in a 0 ℃ refrigerator to give orange-red rod-like crystals as starting material B (7.51g, 57% yield).

Step 2: weighing raw material B (13.44mmol, 7.14g), adding raw material A (16.66mmol, 2.82g), adding THF40mL into the system, reacting at 30 ℃ for 10h under the protection of nitrogen, draining the solvent, washing with n-pentane, and drying the residue in a vacuum drying oven after washing to obtain a red nickel metal complex catalyst (3.56g, yield 57%) for perfluoropolyether polymerization reaction, wherein the red nickel metal complex catalyst has a structure shown in formula (III-2).

HPLC purity: 98.8 percent. Mass spectrum: calculated value 464.06; the test value was 464.31. Elemental analysis: the calculated values are: c: 44.00 percent; h: 6.52 percent; n: 3.02 percent; the test values are: c: 44.12 percent; h: 6.61 percent; n: 3.11 percent.

Example 4

The starting material A was the same as in example 1;

the raw material B has a structure represented by the formula (II-2), Ni (PEt)₃)₄；

The catalyst has a structure represented by formula (III-2):

the preparation method of the catalyst for polymerization reaction of perfluoropolyether comprises the following steps:

step 1: weighing raw materials Ni (cod) under a nitrogen protection system₂(117.1mmol，32.21g)，PEt₃(250.59mmol, 29.61g) was added to the reaction system, 450mL of THF solution was added and reacted at 45 ℃ for 6h under nitrogen, then cooled to room temperature, the solvent THF was drained and extracted with n-pentane, and the extract was placed in a 0 ℃ refrigerator to give orange red rod crystals, B (32.98g, 53% yield).

Step 2, weighing the raw material B (59.23mmol, 31.47g), adding the raw material A (68.11mmol, 11.51g), adding THF (tetrahydrofuran) 155mL into the system, reacting at 30 ℃ for 10h under the protection of nitrogen, draining the solvent, washing by using n-pentane, and drying the residue after washing in a vacuum drying oven to obtain the red nickel metal complex catalyst (16.77g, yield 61%) for the polymerization reaction of the perfluoropolyether, wherein the red nickel metal complex catalyst has the structure shown in the formula (III-2).

HPLC purity: 99.2 percent. Mass spectrum: calculated value 464.06; the test value was 464.31. Elemental analysis: the calculated values are: c: 44.00 percent; h: 6.52 percent; n: 3.02 percent; the test values are: c: 43.92 percent; h: 6.41 percent; n: 2.94 percent.

Example 5

The starting material A was the same as in example 1;

the raw material B has a structure represented by the formula (II-3), Ni (P)ⁱPr₃)₄；

The catalyst has a structure represented by formula (III-3):

the preparation method of the catalyst for polymerization reaction of perfluoropolyether comprises the following steps:

step 1: weighing raw materials Ni (cod) under a nitrogen protection system₂(27.3mmol，7.51g)、PⁱPr₃(triisopropylphosphine) (57.3mmol, 9.18g) was put into the reaction system, 100mL of THF solution was added, refluxing was carried out at 60 ℃ for 6h under nitrogen protection, then cooling was carried out to room temperature, precipitation occurred, THF as a solvent was drained off, extraction was carried out with n-pentane, and the extract was put into a 0 ℃ refrigerator to obtain yellow block crystals as a raw material B (9.83g, yield 63%).

Step 2: weighing raw material B (22.3mmol, 12.74g), adding raw material A (26.76mmol, 4.52g), adding THF (60 mL) into the system, reacting at 40 ℃ for 8h under the protection of nitrogen, draining the solvent, washing with n-pentane, draining the n-pentane, putting the system into a vacuum drying oven for drying, and finally obtaining the final yellow catalyst (3.37g, the yield is 39%) of the nickel metal complex for the polymerization reaction of perfluoropolyether, wherein the catalyst has the structure shown in formula (III-3).

HPLC purity: 99.1 percent. Mass spectrum: calculated value 387.98; the test value was 387.49. Elemental analysis: the calculated values are: c: 43.34 percent; h: 5.46 percent; n: 3.61 percent; the test values are: c: 43.24%; h: 5.22 percent; n: 3.91 percent.

Example 6

The starting material A was the same as in example 1;

the raw material B has a structure represented by the formula (II-3), Ni (P)ⁱPr₃)₄；

The catalyst has a structure represented by formula (III-3):

the preparation method of the catalyst for polymerization reaction of perfluoropolyether comprises the following steps:

step 1: weighing raw materials Ni (cod) under a nitrogen protection system₂(79.5mmol，21.87g)，PⁱPr₃(174.9mmol, 28.02g), adding THF 300mL, reacting at 60 ℃ under nitrogen for 6h, cooling to room temperature, precipitating, draining the solvent THF, extracting with n-pentane, and placing the extract in a 0 ℃ refrigerator to obtain orange block crystals as raw material B (30.4g, 67% yield).

Step 2: weighing raw material B (47.78mmol, 27.30g), adding raw material A (62.11mmol, 10.50g), adding THF 150mL into the system, reacting at 40 ℃ for 8h under the protection of nitrogen, draining the solvent, washing with n-pentane, draining the n-pentane, and drying in a vacuum drying oven to obtain an orange-red powdery nickel metal complex catalyst (7.60g, the yield is 41%) for perfluoropolyether polymerization reaction, wherein the catalyst has a structure shown in formula (III-3).

HPLC purity: 98.9 percent. Mass spectrum: calculated value 387.98; the test value was 387.63. Elemental analysis: the calculated values are: c: 43.34 percent; h: 5.46 percent; n: 3.61 percent; the test values are: c: 43.19%; h: 5.61 percent; n: 3.70 percent.

In the K-type perfluoropolyether polymerization reaction, the catalyst metallic nickel complex for perfluoropolyether polymerization reaction obtained by the reactions of the above examples 1 to 6 and the inorganic metal fluoride are added respectively, and by comparing the polymerization results, the catalytic effect of the metallic nickel complex is obviously better than that of the inorganic metal fluoride, and the specific experimental conditions are as follows: 47g of catalyst, 476g of acetonitrile and 1700g of hexafluoropropylene oxide were added to a 5L mechanical stirred tank under the protection of high purity nitrogen. The effect of different catalysts on the polymerization of hexafluoropropylene oxide was examined at-40 ℃ for 12 hours, and the results are shown in Table 1.

TABLE 1 Effect of different catalysts on the polymerization

Catalyst and process for preparing same	Yield of	Average degree of polymerization DPn (GC)	Average degree of polymerization DPn (NMR)
				CsF	43	4.6	4.7
III-1	83	15.1	15.2
				III-2	74	11.7	11.8
III-3	71	10.9	11.0

As can be seen from the above table, in the polymerization reaction, when the metal organic complex of the present invention is used as a catalyst, the yield of the polymerization reaction and the polymerization degree of perfluoropolyether can be obviously improved; particularly, when III-1 is used as a catalyst, the yield of the polymerization product is the highest and the average polymerization degree is the largest. This shows that the solubility of the catalyst in the solvent greatly affects the polymerization reaction, and the higher the solubility of the catalyst, the more easily the catalyst is ionized into the solvent to form an active ion-pine pair to react with hexafluoropropylene oxide. In addition, in the case of organometallic complexes, substituents coordinated to the metal also have a great influence on the catalytic activity of the catalyst; when the steric hindrance of the substituent group is smaller, the electric supply of the substituent group is stronger, so that the catalyst is easier to react with hexafluoropropylene oxide, and the yield and the polymerization degree of the product are improved.

Of course, the foregoing is only a preferred embodiment of the invention and should not be taken as limiting the scope of the embodiments of the invention. The present invention is not limited to the above examples, and equivalent changes and modifications made by those skilled in the art within the spirit and scope of the present invention should be construed as being included in the scope of the present invention.