A ligand and its preparation method, a metal catalyst and its preparation method and application

Abstract

The present invention discloses a ligand and a preparation method thereof, a metal catalyst and a preparation method thereof and an application thereof. The ligand introduces a silicon-containing group with large steric hindrance into the main structure through a substitution reaction, and connects with the metal active center through a covalent bond, and finally obtains a bimetallic catalyst. The catalyst prepared by the present invention has the characteristics of high activity and small temperature rise in the activation stage. The catalyst can be used to prepare polyether polyols with narrow distribution and flame retardant properties.

Description

Technical Field

[0001] The present invention relates to the field of catalysts, and in particular to a ligand and a preparation method thereof, a metal catalyst and a preparation method and application thereof. Background Art

[0002] Bimetallic catalysts are widely used in the preparation of polyethers because they have higher catalytic activity than traditional alkaline catalysts and do not require post-treatment during preparation and can be used for continuous production.

[0003] Polyurethane (PU) is an important organic polymer material, known as the "fifth plastic". Due to its excellent performance, it is widely used in aerospace, automotive sealing, electronic appliances, building insulation, chemical industry and other fields. Polyurethane materials have the advantages of wide hardness range, oil resistance, moisture resistance, wear resistance, heat insulation, shock absorption and high strength. However, polyurethane materials have disadvantages such as low oxygen index, easy combustion and high smoke density, which limit the wide application of polyurethane materials.

[0004] Polyether polyol is one of the main raw materials for the preparation of polyurethane, so preparing flame-retardant polyether polyol from the source is the most direct way to solve the low oxygen index of polyurethane. However, the polyether polyol currently prepared using traditional bimetallic catalysts has no flame retardant effect, and there is a significant temperature rise (>20°C) during the catalyst activation stage during use, which can easily cause the product molecular weight distribution (PDI) to be wide, affecting product quality. Summary of the invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a ligand and a preparation method thereof, a metal catalyst and a preparation method and application thereof, the prepared catalyst has stable thermal properties, and the polyether polyol prepared using the catalyst of the present invention has a flame retardant effect and a narrow molecular weight distribution.

[0006] In order to achieve the above invention objectives and the above technical effects, the present invention adopts the following technical solutions:

[0007] A ligand, the structural formula of the ligand is:

[0008]

[0009] Wherein, R is CH2 or C=O.

[0010] The present invention also provides a method for preparing the above ligand, which comprises the following steps:

[0011] S1: dehalogenating 1,3-di-tert-butyl-2,2-dichloro-4,4-diphenyl-1,3,2-diazetidine under the action of tert-butyl lithium to obtain product C1;

[0012] S2: subjecting the product C1 to a substitution reaction with 2,2-methylenebisphenol or 2,2'-dihydroxybenzophenone to obtain the product C2;

[0013] In the present invention, the dehalogenation reaction described in S1 is carried out using a strong base tert-butyl lithium in an organic solvent and a low temperature environment; preferably, the organic solvent is ether and / or toluene, wherein the ether is selected from one or more of 1,4-dioxane, THF and diethyl ether.

[0014] In the present invention, the reaction conditions in S1 are reaction temperature of -80 to -120°C and reaction time of 1h to 10h, preferably reaction temperature of -80 to -100°C and reaction time of 2h to 5h; the molar ratio of 1,3-di-tert-butyl-2,2-dichloro-4,4-diphenyl-1,3,2-diazetidine to tert-butyl lithium is 1:1 to 1:1.5, preferably 1:1 to 1:1.1.

[0015] In the present invention, the reaction conditions in S2 are a temperature of 110 to 150° C. and a reaction time of 24 to 50 hours, preferably a reaction temperature of 110 to 120° C. and a time of 30 to 40 hours; the molar ratio of 2,2-methylenebisphenol or 2,2'-dihydroxybenzophenone to the product C1 is 1:2.0 to 1:6.0, preferably 1:2.5 to 1:4.0.

[0016] Preferably, the substitution reaction in step S2 is carried out in an organic solvent or a weakly alkaline environment;

[0017] Preferably, the organic solvent is one or more of DMF, THF, toluene, ether, and 1,4-dioxane;

[0018] Preferably, the weak alkaline environment can be provided by adding one or more bases selected from sodium carbonate, potassium carbonate, and cesium carbonate, with a pH value ranging from 7 to 8.5;

[0019] The reaction route is shown below:

[0020]

[0021] A metal catalyst comprising two or more metal ligands of formula I:

[0022]

[0023] Wherein, M is any one metal element selected from zinc, aluminum, tin, cobalt, iron and magnesium; R is CH2 or C=O, and x is the number of chlorine atoms corresponding to the metal element M, and x is 2, 3 or 4. For example, when M is zinc, X is 2; when M is aluminum, X is 3; and when M is tin, X is 4.

[0024] Preferably, the catalyst comprises two metal ligands of the structure of formula I.

[0025] Preferably, in the catalyst, the molar ratio of the two metals is 2:1 to 1:2.

[0026] Another object of the present invention is to provide a method for preparing a metal catalyst, wherein the ligand of the present invention is reacted with a salt solution of metal M to obtain a crude metal catalyst product.

[0027]

[0028] Preferably, the ligand is added to a THF solution containing the metal M, a coordination reaction is carried out in a weak acid environment provided by a Lewis acid, and the catalyst is obtained after filtering and washing.

[0029] The obtained catalyst is washed with an aqueous solution containing ether.

[0030] Preferably, the ether is soluble in water and has a molecular weight of 200-2000 g / mol, such as PEG500, PEG1000 or PEG2000.

[0031] Preferably, the salt of the metal M is a Lewis acid, preferably zinc chloride, aluminum chloride, tin chloride, cobalt chloride, iron chloride and magnesium chloride.

[0032] More preferably, two or more, preferably two, salts of the metal M are added simultaneously.

[0033] In the present invention, the reaction conditions in S3 are a temperature of 70 to 100° C. and a reaction time of 2 h to 12 h, preferably a reaction temperature of 70 to 80° C. and a reaction time of 2 h to 4 h.

[0034] Preferably, the molar ratio of the added amount of the ligand and the salt of the metal M is 1:1 to 1:20, preferably 1:5 to 1:10.

[0035] Another object of the present invention is to provide a use of the metal catalyst for preparing polyether polyols.

[0036] A method for preparing polyether polyols uses the above catalyst, or a catalyst obtained by the above catalyst preparation method.

[0037] Preferably, the catalyst comprises two or more catalysts of formula I, more preferably two.

[0038] Preferably, the catalyst is added in an amount of 20-80 ppm, such as 30-60 ppm, of the mass of the polyether polyol to be prepared.

[0039] In the present invention, in the preparation method of the polyether polyol, a small molecule polyol or a polyether with a molecular weight greater than 400 g / mol is used as an initiator, and an epoxy compound is used as a monomer.

[0040] Preferably, according to the well-known art, the molecular weight of the initiator is generally less than 10,000.

[0041] The epoxy compound is preferably ethylene oxide, propylene oxide, butylene oxide or the like.

[0042] In the present invention, the method controls the reaction temperature to 100-180° C., preferably 120-140° C., and the pressure to 0.1-0.6 MPa, preferably 0.1-0.3 MPa.

[0043] The pressures described in the present invention are all gauge pressures.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] 1. The catalyst of the present invention connects multiple benzene rings and tert-butyl groups into a three-sided macrocyclic ring through silicon atoms, so that only one side of the metal active center is exposed, thereby inhibiting the reaction activation rate, reducing the temperature rise, and reducing the product PDI (molecular weight distribution).

[0046] 2. The catalyst of the present invention introduces a large steric hindrance silicon group, which can not only fix the metal active center and stabilize the thermal properties of the catalyst, but also has a flame retardant effect.

[0047] 3. The catalyst of the present invention has high activity and has excellent catalytic effect on polyether polyols. DETAILED DESCRIPTION

[0048] The present invention is further described below with reference to the embodiments.

[0049] Main raw material information:

[0050] 1,3-di-tert-butyl-2,2-dichloro-4,4-diphenyl-1,3,2-diazetidine was purchased from Nafu Biotechnology, tert-butyl lithium was purchased from Anage Chemical, 2,2,-methylenebisphenol was purchased from Shandong Xiya Chemical Industry Co., Ltd., toluene was purchased from Anage Chemical, potassium carbonate was purchased from Anage Chemical, PEG500 was purchased from Jiangsu Hai'an Petrochemical Plant, THF was purchased from Komeo, and H45D was purchased from Jiangsu Zhongshan Chemical Co., Ltd.

[0051] The test methods and characterization methods involved in the embodiment are as follows: the molecular weight of the prepared product is tested by high-resolution mass spectrometry (Waters XevoG2QTof), and the sample preparation method is to take a small amount of sample and dissolve it in methanol or acetonitrile for testing; the molecular weight distribution (PDI) of the prepared product is tested by BOEN326985 gel permeation chromatograph; the viscosity of the prepared product is tested by NDJ-79 rotational viscometer; NMR: a small amount of dry sample is added to a nuclear magnetic tube, deuterated dimethyl sulfoxide (DMSO-d6) is added to dissolve, and the ultrasonic dispersion is uniformly dispersed before testing and characterization. Test range: 0-16ppm.

[0052] Example 1

[0053] 1. Synthesis of catalyst:

[0054] 1) Add 0.2 mol of 1,3-di-tert-butyl-2,2-dichloro-4,4-diphenyl-1,3,2-diazetidine into a three-necked flask containing 30 mL of anhydrous THF, replace nitrogen three times, cool the flask to -80°C with liquid nitrogen, evacuate the flask at room temperature for 5 min, repeat this operation three times, pressurize the flask to normal pressure, keep the temperature of the flask below -80°C, add 0.205 mol of tert-butyl lithium into the flask with a needle, stir and react for 5 h, add 50 g of ice water into the flask after the reaction, react for 10 min, and then rotary evaporate the reaction solution to obtain 0.17 mol of solid powder C1.

[0055] 2) 0.04 mol of 2,2-methylenebisphenol and 0.1 mol of product C1 were dissolved in 30 ml of toluene respectively, 2,2-methylenebisphenol and 10 ml of 10% wt potassium carbonate aqueous solution were added to a three-necked flask, the system was heated at 110°C with stirring to condense and reflux, and then the toluene solution of product C1 was slowly added to the system. After reacting for 35 hours, the reaction liquid was rotary evaporated, the obtained solid powder was rinsed three times with pure water and then dried, and then recrystallized once with 400 ml of a mixed solution of ethyl acetate and acetone (volume ratio of 1:6) to obtain 0.035 mol of solid product C2. 13C NMR (125MHz, Common NMR Solvents) δ155.26(s),141.32(s),134.33(s),129.37(s),129.18(d,J=1.8Hz),128. 70(s),127.33(s),124.28(s),123.12(s),97.48(s),54.38(s),32.73(s),31.21(s).

[0056] 3) At 70° C., 0.02 mol of the product of step 2) was added to a solution containing 200 ml of anhydrous THF, 0.1 mol of aluminum chloride and 0.1 mol of zinc chloride, and the mixture was reacted for 2 h. After filtering, the mixture was washed with 500 g of a 1% wt PEG500 aqueous solution, and the solid was placed in a vacuum oven at 100° C. for 4 h to obtain a catalyst product.

[0057] 2. Synthesis of polyether polyols:

[0058] 1) 600 g of polypropylene glycol with a molecular weight of 600 g / mol was mixed as an initiator with 0.036 g of the above-mentioned bimetallic catalyst, the temperature was raised to 100° C., and the mixture was stirred until the materials were evenly dispersed. The temperature was maintained at 100° C., and the mixture was stirred and dehydrated for 2 h under a vacuum environment;

[0059] 2) Raise the temperature to 130°C, add 60g of propylene oxide which is 10% of the mass of the initiator, and observe the pressure change;

[0060] 3) The time for the pressure to drop to half of the initial pressure is 3 minutes, and 540 g of propylene oxide is added to the reaction vessel. During the reaction, the reaction temperature is controlled at 135° C. and the pressure is controlled at 0.2 MPa (by gauge pressure). The reaction is continued until the pressure no longer decreases, and a polyether polyol product is obtained.

[0061] Example 2

[0062] 1. Synthesis of catalyst:

[0063] 1) Add 0.2 mol of 1,3-di-tert-butyl-2,2-dichloro-4,4-diphenyl-1,3,2-diazetidine into a three-necked flask containing 30 mL of anhydrous THF, replace nitrogen three times, cool the flask to -80°C with liquid nitrogen, evacuate the flask at room temperature for 5 min, repeat this operation three times, pressurize the flask to normal pressure, keep the temperature of the flask below -80°C, add 0.210 mol of tert-butyl lithium into the flask with a needle, stir and react for 5 h, add 50 g of ice water into the flask after the reaction, react for 10 min, and then rotary evaporate the reaction solution to obtain 0.17 mol of solid powder C1.

[0064] 2) 0.033 mol of 2,2'-dihydroxybenzophenone and 0.1 mol of product C1 were dissolved in 30 ml of toluene respectively, 2,2-methylenebisphenol and 10 ml of 10% wt potassium carbonate aqueous solution were added to a three-necked flask, the system was heated at 110°C with stirring to condense and reflux, and then the toluene solution of product 1 was slowly added to the system. After reacting for 35 hours, the reaction liquid was rotary evaporated, the obtained solid powder was rinsed three times with pure water and then dried, and then recrystallized once with 400 ml of a mixed solution of ethyl acetate and acetone (volume ratio of 1:6) to obtain 0.029 mol of solid product C2. 13C NMR (125MHz, Common NMR Solvents) δ192.12(s),163.38(s),141.32(s),132.20(d,J=14.7Hz),131.97(s),129. 19(s),128.70(s),127.33(s),124.95(s),123.53(s),97.48(s),54.38(s),31.21(s).

[0065] 3) At 70° C., 0.025 mol of the product of step 2) was added to a solution containing 200 ml of anhydrous THF, 0.025 mol of cobalt chloride and 0.038 mol of zinc chloride, and the mixture was reacted for 2 h. After filtering, the mixture was washed with 500 g of a 1% wt PEG500 aqueous solution, and the solid was placed in a vacuum oven at 100° C. for 4 h to obtain a catalyst product.

[0066] 2. Synthesis of polyether polyols:

[0067] 1) 600 g of polypropylene glycol with a molecular weight of 600 g / mol was mixed as an initiator with 0.036 g of the above-mentioned bimetallic catalyst, the temperature was raised to 100° C., and the mixture was stirred until the materials were evenly dispersed. The temperature was maintained at 100° C., and the mixture was stirred and dehydrated for 2 h under a vacuum environment;

[0068] 2) Raise the temperature to 130°C, add 60g of propylene oxide which is 10% of the mass of the initiator, and observe the pressure change;

[0069] 3) The time for the pressure to drop to half of the initial pressure is 10 minutes, and 540 g of propylene oxide is added to the reaction vessel. During the reaction, the reaction temperature is controlled at 135° C. and the pressure is controlled at 0.2 MPa (by gauge pressure). The reaction is continued until the pressure no longer decreases, and a polyether polyol product is obtained.

[0070] Example 3

[0071] 1. Synthesis of catalyst:

[0072] 1) Add 0.2 mol of 1,3-di-tert-butyl-2,2-dichloro-4,4-diphenyl-1,3,2-diazetidine into a three-necked flask containing 30 mL of anhydrous THF, replace nitrogen three times, cool the flask to -80°C with liquid nitrogen, evacuate with a vacuum pump at room temperature for 5 min, repeat this operation three times, pressurize the flask to normal pressure, keep the temperature of the flask below -80°C, add 0.22 mol of tert-butyl lithium into the flask with a needle, stir and react for 5 h, add 50 g of ice water into the flask after the reaction, react for 10 min, and then rotary evaporate the reaction solution to obtain 0.17 mol of solid powder C1.

[0073] 2) 0.025 mol of 2,2'-dihydroxybenzophenone and 0.1 mol of product C1 were dissolved in 30 ml of toluene respectively, 2,2-methylenebisphenol and 10 ml of 10% wt potassium carbonate aqueous solution were added to a three-necked flask, the system was heated at 110°C with stirring to condense and reflux, and then the toluene solution of product C1 was slowly added to the system. After reacting for 35 hours, the reaction liquid was rotary evaporated, the obtained solid powder was rinsed three times with pure water and then dried, and then recrystallized once with 400 ml of a mixed solution of ethyl acetate and acetone (volume ratio of 1:6) to obtain 0.021 mol of solid product C2. 13C NMR (125MHz, Common NMR Solvents)δ191.32(s),164.81(s),142.16(s),133.65(d),132.87(s),129.76(s) ),128.75(s),128.13(s),125.05(s),124.33(s),97.66(s),54.98(s),31.87(s).

[0074] 3) At 70° C., 0.021 mol of the product of step 2) was added to a solution containing 200 ml of anhydrous THF, 0.025 mol of magnesium chloride and 0.05 mol of zinc chloride, and the mixture was reacted for 2 h. After filtering, the mixture was washed with 500 g of a 1% wt PEG500 aqueous solution, and the solid was placed in a vacuum oven at 100° C. for 4 h to obtain 40 g of a catalyst product.

[0075] 2. Synthesis of polyether polyols:

[0076] 1) 600 g of polypropylene glycol with a molecular weight of 600 g / mol was mixed as an initiator with 0.036 g of the above-mentioned bimetallic catalyst, the temperature was raised to 100° C., and the mixture was stirred until the materials were evenly dispersed. The temperature was maintained at 100° C., and the mixture was stirred and dehydrated for 2 h under a vacuum environment;

[0077] 2) Raise the temperature to 130°C, add 60g of propylene oxide which is 10% of the mass of the initiator, and observe the pressure change;

[0078] 3) The time for the pressure to drop to half of the initial pressure is 4 minutes, and 540 g of propylene oxide is added to the reaction vessel. During the reaction, the reaction temperature is controlled at 135° C. and the pressure is controlled at 0.2 MPa (by gauge pressure). The reaction is continued until the pressure no longer decreases, and a polyether polyol product is obtained.

[0079] Example 4

[0080] At 70° C., 0.01 mol of the ligand prepared in Example 1 was added to a solution containing 200 ml of anhydrous THF, 0.05 mol of ferric chloride and 0.025 mol of cobalt chloride, and the mixture was reacted for 2 h. After filtration, the mixture was washed with 500 g of a 1% wt PEG500 aqueous solution, and the solid was placed in a vacuum oven at 100° C. for 4 h to obtain a catalyst product.

[0081] The polyether polyol was prepared by the same method as in Example 1, except that 0.072 g of the catalyst prepared in this example was added.

[0082] Comparative Example 1

[0083] The difference between this comparative example and the above-mentioned Examples 1, 2 and 3 is that the bimetallic catalyst used in the preparation of the polyether polyol in this comparative example is a commercially available bimetallic catalyst, and the other conditions are the same.

[0084] 1. Commercially available bimetallic catalyst, purchased from Changzhou Hongyu Chemical Co., Ltd., the company's product name is: Changzhou DMC bimetallic catalyst. The bimetallic elements are zinc and cobalt.

[0085] 2. Synthesis of polyether polyols:

[0086] 1) 600 g of polypropylene glycol with a molecular weight of 600 g / mol was mixed as an initiator with 0.036 g of the commercially available bimetallic catalyst, the temperature was raised to 100° C., and the mixture was stirred until the materials were evenly dispersed. The temperature was maintained at 100° C., and the mixture was stirred and dehydrated for 2 h under a vacuum environment;

[0087] 2) Raise the temperature to 130°C, add 60g of propylene oxide, which is about 10% of the mass of the initiator, and then observe the pressure change;

[0088] 3) The time for the pressure to drop to half of the initial pressure is 8 minutes, and 540 g of propylene oxide is added to the reaction vessel. During the reaction, the reaction temperature is controlled at 135° C. and the pressure is controlled at 0.2 MPa (by gauge pressure). The reaction is continued until the pressure no longer decreases, and a polyether polyol product is obtained.

[0089] Performance Test 1:

[0090] The molecular weight of the polyether polyether polyols prepared in Examples 1-4 and the polyether polyols prepared in Comparative Example 1 was tested by high-resolution mass spectrometry (Waters Xevo G2QTof), and the sample preparation method was to take a small amount of sample and dissolve it in methanol or acetonitrile for testing; the molecular weight distribution (PDI) of the prepared product was tested by BOEN326985 gel permeation chromatograph; the viscosity of the prepared product was tested by NDJ-79 rotational viscometer; the results are shown in Table 1.

[0091] Table 1 Test results

[0092]

[0093] Note: The time it takes for the pressure to drop by half is the activation time; Reaction time = total reaction time - activation time

[0094] From the test results of Examples 1, 2, 3, 4 and Comparative Example 1 in Table 1, it can be seen that the temperature at the end of activation of the bimetallic catalyst synthesized by the present invention under the same conditions is lower than that of the commercially available catalyst; comparing Examples 1, 2, 3 and Comparative Example 1, the amount of catalyst added is the same, the molecular weight of the product is not much different, and the reaction time of Example 2 is the shortest, indicating that the activity of the catalyst of Example 2 is the highest; comparing Examples 1 and 3 and Comparative Example 1, the amount of catalyst added in Example 3 is twice that of Example 1, and the activation and reaction times are shortened, but the temperature at the end of activation is high, the PDI is slightly increased, and the viscosity is slightly increased, but they are all better than competing products; comparing the catalysts prepared in Examples 1, 2, 3, 4 of the present invention and Comparative Example 1 for polyether polyols, the PDI and viscosity obtained are better than those of commercially available catalysts.

[0095] Performance Test 2:

[0096] Preparation of polyurethane foam: Take 50 parts of polyether polyols of Examples 1 / 2 / 3 / 4 and Comparative Example 1, 50 parts of H45D, 2 parts of silicone oil, 2 parts of diethanolamine, 20 parts of calcium carbonate, and 3 parts of water respectively, stir evenly, then add 50 parts of isocyanate under high-speed stirring, stir at high speed to mix and foam, and prepare a polyurethane foam product.

[0097] Flame retardant performance test: The polyurethane foam samples were entrusted to Shanghai Ingel Group to test the oxygen index and evaluate the flame retardant performance.

[0098] The results are shown in Table 2:

[0099] performance Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Oxygen index / % 29 32 30 28 21

[0100] Note: Oxygen index greater than 27% is flame retardant

Claims

1. A ligand, characterized in that The structural formula of the ligand is: Wherein, R is CH2 or C=O.

2. A method for preparing the ligand according to claim 1, characterized in that: The preparation method comprises the following steps: S1: dehalogenating 1,3-di-tert-butyl-2,2-dichloro-4,4-diphenyl-1,3,2-diazetidine under the action of tert-butyl lithium to obtain product C1; S2: subjecting the product C1 to a substitution reaction with 2,2-methylenebisphenol or 2,2'-dihydroxybenzophenone to obtain the product C2; The structure of the 1,3-di-tert-butyl-2,2-dichloro-4,4-diphenyl-1,3,2-diazetidine is: The structure of the product C1 is: The structure of the product C2 is: Wherein, R is CH2 or C=O.

3. The method for preparing the ligand according to claim 2, characterized in that: The dehalogenation reaction described in S1 is carried out using a strong base tert-butyl lithium in an organic solvent and a low temperature environment.

4. The method for preparing the ligand according to claim 3, characterized in that: The organic solvent is ether and / or toluene, wherein the ether is selected from one or more of 1,4-dioxane, THF and diethyl ether.

5. The method for preparing the ligand according to claim 3, characterized in that: The reaction conditions in S1 are reaction temperature of -120°C to -80°C and reaction time of 1h to 10h.

6. The method for preparing the ligand according to claim 5, characterized in that: The reaction temperature in S1 is -100°C to -80°C, and the reaction time is 2h to 5h.

7. The method for preparing the ligand according to claim 2, characterized in that: The molar ratio of 1,3-di-tert-butyl-2,2-dichloro-4,4-diphenyl-1,3,2-diazetidine to tert-butyl lithium is 1:1 to 1:1.

5.

8. The method for preparing the ligand according to claim 7, characterized in that: The molar ratio of 1,3-di-tert-butyl-2,2-dichloro-4,4-diphenyl-1,3,2-diazetidine to tert-butyl lithium is 1:1 to 1:1.

1.

9. The method for preparing the ligand according to claim 2, characterized in that: The reaction conditions in S2 are a temperature of 110 to 150° C. and a reaction time of 24 to 50 hours.

10. The method for preparing the ligand according to claim 9, characterized in that: In S2, the reaction temperature is 110-120°C and the reaction time is 30h-40h.

11. The method for preparing the ligand according to claim 2, characterized in that: The molar ratio of 2,2-methylenebisphenol or 2,2'-dihydroxybenzophenone to the product C1 is 1:2.0 to 1:6.

0.

12. The method for preparing the ligand according to claim 11, characterized in that: The molar ratio of 2,2-methylenebisphenol or 2,2'-dihydroxybenzophenone to the product C1 is 1:2.5 to 1:4.

0.

13. The method for preparing the ligand according to claim 2, characterized in that: The substitution reaction described in step S2 is carried out in an organic solvent and a weakly alkaline environment.

14. The method for preparing the ligand according to claim 13, characterized in that: In step S2, the organic solvent is one or more of DMF, THF, toluene, diethyl ether, and 1,4-dioxane.

15. The method for preparing the ligand according to claim 13, characterized in that: The weak alkaline environment is provided by adding one or more bases selected from sodium carbonate, potassium carbonate and cesium carbonate, and the pH value ranges from 7 to 8.

5.

16. A metal catalyst, characterized in that The catalyst comprises two or more metal ligands of formula I: Wherein, M is any one metal element selected from zinc, aluminum, tin, cobalt, iron and magnesium; R is CH2 or C=O, and x is the number of chlorine atoms corresponding to the metal element M, and x is 2, 3 or 4.

17. The metal catalyst according to claim 16, wherein The catalyst comprises two metal ligands of the formula I.

18. The metal catalyst according to claim 16, wherein In the catalyst, the molar ratio of the two metals is 2:1 to 1:

2.

19. A method for preparing the metal catalyst according to claim 16, comprising reacting the ligand according to claim 1 with a salt solution of metal M to obtain the metal catalyst.

20. The preparation method according to claim 19, characterized in that: The ligand is added to a THF solution containing the metal M, and a coordination reaction is carried out in a weak acid environment provided by a Lewis acid. The catalyst is obtained after filtering and washing.

21. The preparation method according to claim 19, characterized in that: The salt of the metal M is a Lewis acid.

22. The preparation method according to claim 21, characterized in that: The salt of the metal M is selected from zinc chloride, aluminum chloride, tin chloride, cobalt chloride, ferric chloride and magnesium chloride.

23. The preparation method according to claim 19, characterized in that: Two or more salts of the metal M are added simultaneously.

24. The preparation method according to claim 23, characterized in that: Two salts of metal M are added simultaneously.

25. The preparation method according to claim 19, characterized in that: The reaction conditions are temperature 70-100°C and reaction time 2h-12h.

26. The preparation method according to claim 25, characterized in that: The reaction temperature is 70-80°C and the time is 2h-4h.

27. The preparation method according to claim 19, characterized in that: The molar ratio of the added amount of the ligand and the salt of the metal M is 1:1 to 1:

20.

28. The preparation method according to claim 27, characterized in that: The molar ratio of the added amount of the ligand and the salt of the metal M is 1:5 to 1:

10.

29. Use of the metal catalyst according to any one of claims 16 to 18 or the metal catalyst prepared by the preparation method according to any one of claims 19 to 28 for preparing polyether polyols.

30. The use according to claim 29, wherein The amount of the catalyst added is 20-80 ppm of the mass of the polyether polyol to be prepared.

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