Aluminum-zinc catalyst, preparation method thereof and application of aluminum-zinc catalyst in preparation of polyoxyethylene

Abstract

The invention provides an aluminum-zinc catalyst, a preparation method thereof and application of the aluminum-zinc catalyst in preparation of polyoxyethylene. A sol-gel method is adopted, an organic alcohol aluminum salt, an organic zinc compound and a chelating agent are mixed with hydrochloric acid in water to form sol, and the catalyst is prepared through sol and gel conversion, drying and roasting. The catalyst can solve the problem of synthesis of a high molecular weight polyoxyethylene catalyst, high-quality polyoxyethylene is prepared by virtue of a special catalyst and a precise process, the harsh requirements on materials in the fields of medicines, daily chemicals and the like can be met, and the catalyst has extremely high application and popularization values.

Description

Technical Field

[0001] The invention belongs to the field of high molecular polymer synthesis, and particularly relates to an aluminum zinc catalyst, a preparation method thereof, and application of the catalyst in the preparation of polyethylene oxide. Background Art

[0002] Polyethylene oxide (EPO) is a polymer formed by ring-opening polymerization of ethylene oxide. Its general chemical structure is -(CH2CH2O) n -, exhibiting a linear molecular chain morphology. The degree of polymerization (n) directly determines the molecular weight of polyethylene oxide, and the two are positively correlated: the higher the degree of polymerization, the larger the molecular weight. According to Part IV of the 2020 edition of the Chinese Pharmacopoeia, the average number of oxyethylene groups in polyethylene oxide, n, is 2,000 to 20,000. The oxygen atoms in the molecular chain are connected to adjacent carbon atoms via ether bonds, and this ether bond structure gives polyethylene oxide many unique properties. The ether bond has a certain polarity, which enables polyethylene oxide molecules to form hydrogen bonds with water molecules, thereby exhibiting good water solubility.

[0003] Polyethylene oxide (PEO) is widely used in numerous industries, including cosmetics, textiles, and pharmaceuticals, due to its excellent water solubility, low toxicity, good thermoplasticity, and unique expansion and dissolution properties. High-polymerization-degree PEO (molecular weight 4-5 million) exhibits even more outstanding performance. However, conventional catalysts often suffer from insufficient activity and poor selectivity when catalyzing the synthesis of these high-polymerization-degree products, resulting in poor molecular weight distribution of PEO. Therefore, the development of new, highly active and efficient catalysts is urgently needed. Summary of the Invention

[0004] To address the aforementioned issues of the prior art, the present invention provides an aluminum-zinc bimetallic catalyst, a preparation method thereof, and its use in the preparation of high-molecular-weight polyethylene oxide. This invention utilizes a unique sol-gel method, combined with high-temperature annealing and etching processes, to produce a catalyst with highly dispersed and appropriately active sites. In polyethylene oxide polymerization reactions, the catalyst exhibits excellent catalytic activity and selectivity. The bimetallic active sites can synergize the catalyst in the polymerization of ethylene oxide monomer, effectively suppressing side reactions and successfully achieving the efficient synthesis of polyethylene oxide with a molecular weight of 4 to 5 million. This provides a high-quality raw material guarantee for the application of polyethylene oxide in high-end applications.

[0005] To achieve the above objectives, the present invention provides the following technical solutions.

[0006] A method for preparing an aluminum-zinc catalyst comprises the following steps: (1) uniformly mixing an organic alcohol aluminum salt, an organic zinc compound, and a chelating agent in an organic solvent, then adding water dropwise, and then mixing with a hydrochloric acid solution to form a sol; (2) allowing the sol to stand to form a gel; (3) After drying the gel, calcining it at 600-800° C. under an inert atmosphere to obtain the aluminum-zinc catalyst.

[0007] Preferably, the organic alcohol aluminum salt is one or more of aluminum isopropoxide, aluminum ethoxide, aluminum tert-butoxide or aluminum n-propoxide.

[0008] Preferably, the organic zinc compound is one or more of diethyl zinc, zinc acetylacetonate, zinc acetate or zinc stearate.

[0009] Preferably, the usage ratio of the organic alcohol aluminum salt and the organic zinc compound in step (1) satisfies the following: the molar ratio of aluminum element to zinc element is (0.5-3):1.

[0010] Preferably, the organic solvent in step (1) is ethanol, specifically anhydrous ethanol.

[0011] Preferably, the volume mass ratio of the organic solvent to the chelating agent in step (1) is (100-200 mL):(1-2 g).

[0012] Preferably, the chelating agent in step (1) is one or more of acetylacetone, ethylenediaminetetraacetic acid (EDTA) or citric acid.

[0013] Preferably, the volume ratio of the water in step (1) to the hydrochloric acid solution is (1-2): (1-2).

[0014] Preferably, the concentration of the hydrochloric acid solution in step (1) is 0.05-0.2 mol / L.

[0015] Preferably, the mixing process with the hydrochloric acid solution in step (1) is carried out at 35-45°C.

[0016] Preferably, the mixing time with the hydrochloric acid solution in step (1) is 1 to 2 hours.

[0017] Preferably, the standing time in step (2) is 24 to 30 hours.

[0018] Preferably, the drying temperature in step (3) is 80-120°C.

[0019] Preferably, the drying time in step (3) is 24 to 30 hours.

[0020] Preferably, the drying in step (3) is vacuum drying.

[0021] Preferably, the calcination time in step (3) is 2 to 6 hours.

[0022] The second object of the present invention is to provide an aluminum-zinc catalyst prepared by the above preparation method.

[0023] A third object of the present invention is to provide the use of the aluminum-zinc catalyst prepared by the above-mentioned preparation method in the preparation of polyethylene oxide. The catalyst has highly active centers and stable performance. High-molecular-weight polyethylene oxide can be produced using this catalyst.

[0024] Furthermore, the application is to prepare polyethylene oxide with a viscosity-average molecular weight in the range of 4 to 5 million.

[0025] The beneficial effects of the present invention are: The aluminum-zinc bimetallic synergistic catalyst provided by the present invention, prepared by the sol-gel method, has high activity and good selectivity. Its unique microstructure can accurately guide the polymerization of ethylene oxide, reduce unnecessary side reactions, lay the foundation for the synthesis of high-molecular-weight polyoxyethylene, and better meet the stringent requirements for polyoxyethylene quality in high-end medicine, precision industrial manufacturing and other fields.

[0026] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention. DETAILED DESCRIPTION

[0027] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0028] Unless otherwise specified, the percentage content involved in the present invention refers to mass percentage for solid-liquid mixing and solid-solid mixing, and refers to volume percentage for liquid-liquid mixing.

[0029] Unless otherwise specified, percentage concentrations referred to in the present invention refer to final concentrations, which refer to the percentage of an added component in the system after the addition of the component.

[0030] The temperature parameters in the present invention, unless otherwise specified, allow for either constant temperature treatment or treatment within a certain temperature range. The constant temperature treatment allows for temperature fluctuations within the precision range controlled by the instrument.

[0031] Sources of experimental materials and reagents: Other materials, reagents, etc. used in the examples of the present invention can be obtained from commercial sources, as shown in Table 1.

[0032] Table 1 Sources of experimental materials and reagents Serial number Raw material information purity Manufacturer 1 Aluminum isopropylate ≥99.8% Shanghai MacLean Biochemical Technology Co., Ltd. 2 Aluminum ethoxide 98% Shanghai MacLean Biochemical Technology Co., Ltd. 3 Zinc acetylacetonate Reagent grade, 98% Shanghai MacLean Biochemical Technology Co., Ltd. 4 Zinc stearate 99% Shanghai MacLean Biochemical Technology Co., Ltd. 5 EDTA 99.5% Shanghai MacLean Biochemical Technology Co., Ltd. 6 citric acid ≥99.5%(T) Shanghai MacLean Biochemical Technology Co., Ltd. 7 hydrochloric acid analytically pure Nanjing Chemical Reagents 8 Fumed silica <![CDATA[Hydrophobic specific surface area: 300 m 2 / g]]> Shanghai Aladdin Biochemical Technology Co., Ltd. 9 Isopentane ≥98% Shanghai Aladdin Biochemical Technology Co., Ltd. 10 Ethylene oxide Industrial grade Jiangsu Dena Chemical Co., Ltd. Detection method: The viscosity average molecular weight detection method used in the embodiments of the present invention is to test the intrinsic viscosity [η] of the polyethylene oxide aqueous solution according to the national standard GB1632-1979, and then calculate the viscosity average molecular weight of the product according to the Mark-Houwink formula: [η] = 12.5 × 10 －5 × M V 0.78 ; Where: M v is the viscosity-average molecular weight of the product, g / mol; [η] is the intrinsic viscosity of the product, dL / g.

[0033] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0034] Example 1 (1) Synthesis of catalyst: 10g of aluminum isopropoxide and 12.9g of zinc acetylacetonate were used as precursors, with a molar ratio of aluminum to zinc of 1:1. The precursors were added to 100ml of anhydrous ethanol solvent until the precursors were completely submerged. Subsequently, 1g of ethylenediaminetetraacetic acid was added to the solvent, and magnetic stirring was initiated for 2 hours until a homogeneous mixed solution was formed. Subsequently, 50ml of deionized water was slowly added dropwise, followed by 50ml of 0.1mol / L hydrochloric acid solution. The mixture was stirred at 35°C for 2 hours until a uniform sol formed. The sol was allowed to stand at room temperature for 24 hours until it converted into a gel, and then dried in a vacuum drying oven at 100°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 600°C for 4 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0035] (2) Ethylene oxide polymerization: 0.1g of the above catalyst was added to a tightly sealed 2L reactor with mechanical stirring and nitrogen. 3.2g of nanosilica, 500g of isopentane, and 200g of ethylene oxide were then added. The polymerization temperature was 35°C, the speed was 200 rpm, and the reaction time was 16 hours. The resulting polyethylene oxide was a white powder with uniform particle size. The viscosity-average molecular weight of the synthesized PEO was 5.13 million, and the polymerization yield was 98.6%.

[0036] Example 2 (1) Synthesis of catalyst: 10g of aluminum isopropoxide and 15g of zinc acetylacetonate were used as precursors, with a molar ratio of aluminum to zinc of 1:1. The precursors were added to 100ml of anhydrous ethanol solvent until the precursors were completely submerged. Subsequently, 1.5g of ethylenediaminetetraacetic acid was added to the solvent, and magnetic stirring was initiated for 2 hours until a homogeneous mixed solution was formed. Subsequently, 50ml of deionized water was slowly added dropwise, followed by 50ml of 0.2mol / L hydrochloric acid solution. The mixture was stirred at 35°C for 2 hours until a homogeneous sol was formed. The sol was allowed to stand at room temperature for 24 hours until it converted into a gel, and then dried in a vacuum drying oven at 100°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 700°C for 4 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0037] (2) Ethylene oxide polymerization: The polymerization process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyethylene oxide was 4.97 million, and the polymerization yield was 97.3%.

[0038] Example 3 (1) Synthesis of catalyst: 10g of aluminum isopropoxide and 22.5g of zinc acetylacetonate were used as precursors, with a molar ratio of aluminum to zinc of 1:1.5. The precursors were added to 200ml of anhydrous ethanol solvent until the precursors were completely submerged. Subsequently, 1.5g of ethylenediaminetetraacetic acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution was formed. Subsequently, 100ml of deionized water was slowly added dropwise, followed by 100ml of 0.2mol / L hydrochloric acid solution. The mixture was stirred at 35°C for 2 hours until a homogeneous sol was formed. The sol was allowed to stand at room temperature for 24 hours until it converted into a gel, and then dried in a vacuum drying oven at 100°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 700°C for 4 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0039] (2) Ethylene oxide polymerization: The polymerization process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyethylene oxide was 4.66 million, and the polymerization yield was 97.9%.

[0040] Example 4 (1) Synthesis of catalyst: 10g of aluminum isopropoxide and 30g of zinc acetylacetonate were used as precursors, with a molar ratio of aluminum to zinc of 1:2. The precursors were added to 200ml of anhydrous ethanol solvent until the precursors were completely submerged. Subsequently, 1.5g of ethylenediaminetetraacetic acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution was formed. Subsequently, 100ml of deionized water was slowly added dropwise, followed by 100ml of 0.2mol / L hydrochloric acid solution. The mixture was stirred at 40°C for 2 hours until a homogeneous sol was formed. The sol was allowed to stand at room temperature for 24 hours until it converted into a gel, and then dried in a vacuum drying oven at 100°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 800°C for 3 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0041] (2) Ethylene oxide polymerization: The polymerization operation process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 4.08 million, and the polymerization yield was 99.2%.

[0042] Example 5 (1) Synthesis of catalyst: 10g of aluminum isopropoxide and 31g of zinc stearate, with a molar ratio of aluminum to zinc of 1:1, were added to 200ml of anhydrous ethanol solvent until the precursor was completely submerged. Subsequently, 2g of ethylenediaminetetraacetic acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution was formed. Subsequently, 100ml of deionized water was slowly added dropwise, followed by 100ml of 0.2mol / L hydrochloric acid solution. The mixture was stirred at 45°C for 2 hours until a uniform sol formed. The sol was allowed to stand at room temperature for 24 hours until it converted into a gel, and then dried in a vacuum drying oven at 100°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 800°C for 6 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0043] (2) Ethylene oxide polymerization: The polymerization operation process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 5.08 million, and the polymerization yield was 97.9%.

[0044] Example 6 (1) Synthesis of catalyst: 10g of aluminum isopropoxide and 46.5g of zinc stearate, with a molar ratio of aluminum to zinc of 1:1.5, were added to 200ml of anhydrous ethanol solvent until the precursor was completely submerged. Subsequently, 2g of citric acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution was formed. Subsequently, 100ml of deionized water was slowly added dropwise, followed by 100ml of 0.2mol / L hydrochloric acid solution. The mixture was stirred at 45°C for 2 hours until a uniform sol formed. The sol was allowed to stand at room temperature for 30 hours until it converted into a gel, and then dried in a vacuum drying oven at 120°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 800°C for 6 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0045] (2) Ethylene oxide polymerization: The polymerization process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 4.56 million, and the polymerization yield was 96.7%.

[0046] Example 7 (1) Synthesis of catalyst: 10g of aluminum isopropoxide and 62g of zinc stearate, with a molar ratio of aluminum to zinc of 1:2, were added to 200ml of anhydrous ethanol solvent until the precursors were completely submerged. Subsequently, 2g of citric acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution was formed. Subsequently, 100ml of deionized water was slowly added dropwise, followed by 100ml of 0.2mol / L hydrochloric acid solution. The mixture was stirred at 45°C for 2 hours until a uniform sol formed. The sol was allowed to stand at room temperature for 30 hours until it converted into a gel, and then dried in a vacuum drying oven at 80°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 800°C for 6 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0047] (2) Ethylene oxide polymerization: The polymerization operation process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 4.39 million, and the polymerization yield was 95.9%.

[0048] Example 8 (1) Synthesis of catalyst: 10g of aluminum isopropoxide and 31g of zinc stearate were used as precursors, with a molar ratio of aluminum to zinc of 1:1. The precursors were added to 200ml of anhydrous ethanol solvent until the precursors were completely submerged. Subsequently, 2g of citric acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution was formed. Subsequently, 100ml of deionized water was slowly added dropwise, followed by 100ml of 0.1mol / L hydrochloric acid solution. The mixture was stirred at 45°C for 2 hours until a uniform sol was formed. The sol was allowed to stand at room temperature for 30 hours until it converted into a gel, and then dried in a vacuum drying oven at 120°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 800°C for 4 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0049] (2) Ethylene oxide polymerization: The polymerization operation process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 4.86 million, and the polymerization yield was 99.1%.

[0050] Example 9 (1) Synthesis of catalyst: 10g of aluminum ethoxide and 39g of zinc stearate, with a molar ratio of aluminum to zinc of 1:1, were added to 200ml of anhydrous ethanol solvent until the precursor was completely submerged. Subsequently, 2g of citric acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution was formed. Subsequently, 200ml of deionized water was slowly added dropwise, followed by 100ml of a 0.1mol / L hydrochloric acid solution. The mixture was stirred at 45°C for 2 hours until a uniform sol was formed. The sol was allowed to stand at room temperature for 30 hours until it converted into a gel, and then dried in a vacuum drying oven at 120°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 800°C for 4 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0051] (2) Ethylene oxide polymerization: The polymerization operation process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 4.89 million, and the polymerization yield was 98.3%.

[0052] Example 10 (1) Synthesis of catalyst: 10g of aluminum ethoxide and 58.5g of zinc stearate, with a molar ratio of aluminum to zinc of 1:1.5, were added to 200ml of anhydrous ethanol solvent until the precursor was completely submerged. Subsequently, 2g of citric acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution was formed. Subsequently, 100ml of deionized water was slowly added dropwise, followed by 200ml of 0.1mol / L hydrochloric acid solution. The mixture was stirred at 45°C for 2 hours until a uniform sol formed. The sol was allowed to stand at room temperature for 30 hours until it converted into a gel, and then dried in a vacuum drying oven at 120°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 800°C for 4 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0053] (2) Ethylene oxide polymerization: The polymerization process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 4.43 million, and the polymerization yield was 96.3%.

[0054] Example 11 (1) Synthesis of catalyst: 10g of aluminum ethoxide and 19g of zinc acetylacetonate were used as precursors, with a molar ratio of aluminum to zinc of 1:1. The precursors were added to 100ml of anhydrous ethanol solvent until the precursors were completely submerged. Subsequently, 1g of citric acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution was formed. Subsequently, 100ml of deionized water was slowly added dropwise, followed by 100ml of 0.1mol / L hydrochloric acid solution. The mixture was stirred at 45°C for 2 hours until a uniform sol formed. The sol was allowed to stand at room temperature for 30 hours until it converted into a gel, and then dried in a vacuum drying oven at 120°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 700°C for 2 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0055] (2) Ethylene oxide polymerization: The polymerization process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 5.06 million, and the polymerization yield was 96.3%.

[0056] Example 12 (1) Synthesis of catalyst: 10g of aluminum ethoxide and 19g of zinc acetylacetonate were used as precursors, with a molar ratio of aluminum to zinc of 1:1. The precursors were added to 100ml of anhydrous ethanol solvent until the precursors were completely submerged. Subsequently, 2g of ethylenediaminetetraacetic acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution was formed. Subsequently, 100ml of deionized water was slowly added dropwise, followed by 100ml of 0.05mol / L hydrochloric acid solution. The mixture was stirred at 45°C for 2 hours until a uniform sol formed. The sol was allowed to stand at room temperature for 30 hours until it converted into a gel, and then dried in a vacuum drying oven at 120°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 700°C for 2 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0057] (2) Ethylene oxide polymerization: The polymerization process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 4.94 million, and the polymerization yield was 98.2%.

[0058] Example 13 (1) Synthesis of catalyst 10g of aluminum ethoxide and 28.5g of zinc acetylacetonate were used as precursors, with a molar ratio of aluminum to zinc of 1:1.5. The precursors were added to 100ml of anhydrous ethanol solvent until the precursors were completely submerged. Subsequently, 2g of ethylenediaminetetraacetic acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution was formed. Subsequently, 100ml of deionized water was slowly added dropwise, followed by 100ml of 0.2mol / L hydrochloric acid solution. The mixture was stirred at 45°C for 1 hour until a homogeneous sol was formed. The sol was allowed to stand at room temperature for 30 hours until it converted into a gel, and then dried in a vacuum drying oven at 120°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 800°C for 2 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0059] (2) Ethylene oxide polymerization: The polymerization operation process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 4.62 million, and the polymerization yield was 97.0%.

[0060] Example 14 (1) Synthesis of catalyst: 10g of aluminum ethoxide and 28.5g of zinc acetylacetonate were used as precursors, with a molar ratio of aluminum to zinc of 1:1.5. The precursors were added to 200ml of anhydrous ethanol solvent until the precursors were completely submerged. Subsequently, 2g of ethylenediaminetetraacetic acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution was formed. Subsequently, 100ml of deionized water was slowly added dropwise, followed by 100ml of 0.1mol / L hydrochloric acid solution. The mixture was stirred at 45°C for 2 hours until a homogeneous sol was formed. The sol was allowed to stand at room temperature for 30 hours until it converted into a gel, and then dried in a vacuum drying oven at 120°C for 24 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 800°C for 6 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0061] (2) Ethylene oxide polymerization: The polymerization operation process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 4.52 million, and the polymerization yield was 99.3%.

[0062] Example 15 (1) Synthesis of catalyst: 10g of aluminum ethoxide and 38g of zinc acetylacetonate were used as precursors, with a molar ratio of aluminum to zinc of 1:2. The precursors were added to 200ml of anhydrous ethanol solvent until the precursors were completely submerged. Subsequently, 2g of ethylenediaminetetraacetic acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution formed. Subsequently, 100ml of deionized water was slowly added dropwise, followed by 100ml of 0.05mol / L hydrochloric acid solution. The mixture was stirred at 45°C for 2 hours until a homogeneous sol formed. The sol was allowed to stand at room temperature for 30 hours until it converted into a gel, and then dried in a vacuum drying oven at 120°C for 30 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 800°C for 6 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0063] (2) Ethylene oxide polymerization: The polymerization operation process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 4.23 million, and the polymerization yield was 98.1%.

[0064] Example 16 (1) Synthesis of catalyst: Aluminum tert-butoxide and diethylzinc were used as precursors, with a molar ratio of aluminum to zinc of 1:3. The precursors were added to 200 ml of anhydrous ethanol solvent until the precursors were completely submerged. Subsequently, 2 g of ethylenediaminetetraacetic acid was added to the solvent, and magnetic stirring was initiated for 3 hours until a homogeneous mixed solution was formed. Subsequently, 100 ml of deionized water was slowly added dropwise, followed by 100 ml of 0.2 mol / L hydrochloric acid solution. The mixture was stirred at 45°C for 2 hours until a uniform sol formed. The sol was allowed to stand at room temperature for 30 hours until it converted into a gel, and then dried in a vacuum drying oven at 120°C for 30 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 800°C for 6 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0065] (2) Ethylene oxide polymerization: The polymerization operation process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 4.01 million, and the polymerization yield was 95.3%.

[0066] Example 17 (1) Synthesis of catalyst: Aluminum n-propoxide and zinc acetate were used as precursors, with a molar ratio of aluminum to zinc of 1:1. They were added to 100 ml of anhydrous ethanol solvent until the precursors were completely submerged. Subsequently, 1.5 g of acetylacetone was added to the solvent, and magnetic stirring was initiated for 3 hours until a uniform mixed solution was formed. Subsequently, 200 ml of deionized water was slowly added dropwise, followed by 200 ml of a 0.1 mol / L hydrochloric acid solution. The mixture was stirred at 45°C for 2 hours until a uniform sol was formed. The sol was allowed to stand at room temperature for 30 hours until it converted into a gel, and then dried in a vacuum drying oven at 120°C for 28 hours. The dried sample was placed in a tube furnace under a nitrogen atmosphere and calcined at 800°C for 2 hours to obtain a highly active aluminum-zinc bimetallic synergistic catalyst.

[0067] (2) Ethylene oxide polymerization: The polymerization operation process was the same as that of Example 1. The viscosity-average molecular weight of the prepared polyoxyethylene was 4.89 million, and the polymerization yield was 98.9%.

[0068] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with this profession can make slight changes or modifications to equivalent embodiments of the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing an aluminum-zinc catalyst, characterized in that: The steps include: (1) uniformly mixing an organic alcohol aluminum salt, an organic zinc compound, and a chelating agent in an organic solvent, then adding water dropwise, and then mixing with a hydrochloric acid solution to form a sol; (2) allowing the sol to stand to form a gel; (3) After drying the gel, calcining it at 600-800° C. under an inert atmosphere to obtain the aluminum-zinc catalyst.

2. The preparation method according to claim 1, characterized in that The organic alcohol aluminum salt is one or more of aluminum isopropoxide, aluminum ethoxide, aluminum tert-butoxide or aluminum n-propoxide.

3. The preparation method according to claim 1, characterized in that The organic zinc compound is one or more of diethyl zinc, zinc acetylacetonate, zinc acetate or zinc stearate.

4. The preparation method according to claim 1, characterized in that The amount ratio of the organic alcohol aluminum salt and the organic zinc compound in step (1) satisfies: the molar ratio of the aluminum element to the zinc element is (0.5-3):

1.

5. The preparation method according to claim 1, characterized in that The chelating agent in step (1) is one or more of acetylacetone, ethylenediaminetetraacetic acid or citric acid.

6. The preparation method according to claim 1, characterized in that The volume mass ratio of the organic solvent to the chelating agent in step (1) is (100-200 mL): (1-2 g).

7. The preparation method according to claim 1, characterized in that The standing time described in step (2) is 24 to 30 hours.

8. The preparation method according to claim 1, characterized in that The calcination time in step (3) is 2 to 6 hours.

9. The aluminum-zinc catalyst prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the aluminum-zinc catalyst prepared by the preparation method according to any one of claims 1 to 8 in the preparation of polyethylene oxide.