Preparation method of metal catalyst for preparing polyether polyol
The method of modifying mesoporous silica and loading tri(pentafluorophenyl)borane and cobalt-zinc bimetallic skeleton solves the problems of wide molecular weight distribution and poor reactivity in the synthesis of polyether polyols in the existing technology, and achieves efficient, stable catalytic effect and low-energy synthesis.
Patent Information
- Application Number
- CN202510948181.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-10
- Publication Date
- 2025-10-10
AI Technical Summary
The existing methods for synthesizing polyether polyols have the disadvantages of broadening the molecular weight of the products and producing many by-products. In addition, the ends of the polyether polyols initiated by the catalyst are mainly secondary hydroxyl groups, resulting in poor reactivity with isocyanates and poor water resistance and wet heat stability of polyurethane products.
A mesoporous silica modification method was adopted, in which γ-aminopropyltriethoxysilane and octyltrimethoxysilane were used to modify the mesoporous silica, and tris(pentafluorophenyl)borane and cobalt-zinc bimetallic organic framework were loaded to form a stable metal catalyst, thereby improving the hydrophobicity and catalytic efficiency.
The primary hydroxyl content of the polyether polyol is increased, the unsaturation is reduced, the hydrophobicity and stability of the catalyst are enhanced, the synthesis energy consumption is reduced, and it is in line with the concept of green synthesis.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of metal catalyst preparation, and particularly relates to a preparation method of a metal catalyst for preparing polyether polyol. BACKGROUND
[0002] Polyether polyol is one of main raw materials of polyurethane, which is usually prepared by ring-opening polymerization of epoxy monomers such as propylene oxide under the action of a catalyst with low relative molecular mass polyol as a starter. Polyurethane is usually prepared from isocyanate and polyether polyol, and the hydroxyl functionality, molecular weight and terminal hydroxyl group of the polyether polyol have a decisive influence on the chemical and physical properties of the polyurethane, so the polyether polyol is one of key raw materials for preparing polyurethane products.
[0003] At present, the synthesis of polyether polyol mainly adopts anion ring-opening polymerization, cation ring-opening polymerization and coordination ring-opening polymerization. However, the products generated by these methods have problems such as relatively wide molecular weight, many by-products and product tailing. In addition, the catalysts such as Lewis acid and double metal cyanide complex used in the synthesis process initiate the polymerization of propylene oxide to generate polyether polyol with mainly secondary hydroxyl groups at the terminal, which has poor reactivity with isocyanate groups, and the end-capping of the secondary hydroxyl groups with ethylene oxide will lead to poor water resistance and hygrothermal stability of the polyurethane product.
[0004] Therefore, it is of great significance to invent a metal catalyst for preparing polyether polyol. SUMMARY
[0005] The present application aims to provide a preparation method of a metal catalyst for preparing polyether polyol to solve the problems in the prior art.
[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: A preparation method of a metal catalyst for preparing polyether polyol, characterized by comprising the following steps: S1: adding mesoporous silica to an ethanol aqueous solution containing gamma-aminopropyl triethoxysilane, heating and reacting, washing and drying to obtain aminated mesoporous silica; S2: adding the aminated mesoporous silica to anhydrous ethanol containing octyl trimethoxysilane, heating and reacting, washing and drying to obtain modified mesoporous silica; S3: dissolving the modified mesoporous silica and tris(pentafluorophenyl)borane in toluene containing deionized water catalyst, heating and reacting, washing and drying to obtain tris(pentafluorophenyl)borane modified mesoporous silica; S4: adding tris(pentafluorophenyl)borane-modified mesoporous silica, cobalt-zinc bimetallic precursor and 2,5-dichloroterephthalic acid to a mixed solvent, then adding fluoroboric acid catalyst, heating for reaction, washing and drying to obtain a metal catalyst.
[0007] Furthermore, in step S1, the mass ratio of mesoporous silica to γ-aminopropyltriethoxysilane is 1:(0.5-0.8), the reaction temperature is 80-100° C., and the reaction time is 20-24 h.
[0008] Furthermore, in step S2, the mass ratio of amino-modified mesoporous silica to octyltrimethoxysilane is 1:(0.2-0.4), the reaction temperature is 60-80° C., and the reaction time is 8-12 h.
[0009] Furthermore, in step S3, the mass ratio of modified mesoporous silica to tris(pentafluorophenyl)borane is 1:(1-1.2), the reaction temperature is 90-110° C., and the reaction time is 70-76 h.
[0010] Furthermore, in step S4, the cobalt-zinc bimetallic precursor is cobalt chloride hexahydrate and zinc chloride, and the mass ratio of tris(pentafluorophenyl)borane-modified mesoporous silica, cobalt chloride hexahydrate, zinc chloride and 2,5-dichloroterephthalic acid is 1:(0.1-0.15):(0.08-0.12):(0.03-0.1).
[0011] Furthermore, in step S4, the heating reaction temperature is 100-120° C., and the reaction time is 20-24 h.
[0012] Furthermore, in step S3, the mass ratio of toluene to deionized water catalyst is 1:(0.2-0.3).
[0013] Furthermore, in step S4, the concentration of the solution containing the fluoroboric acid catalyst is 3-5 wt %.
[0014] Furthermore, in step S4, the mixed solvent is N,N-dimethylformamide and ethanol, and the mass ratio of N,N-dimethylformamide to ethanol is (1-10):(1-3).
[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The mesoporous silica into which the metal catalyst is introduced is modified with γ-aminopropyltriethoxysilane and octyltrimethoxysilane. The amino groups on γ-aminopropyltriethoxysilane are weakly alkaline, so they can be hydrolyzed without pH adjustment and then grafted onto the surface of the mesoporous silica. The amino functional groups on them can coordinate with cobalt-zinc ions, allowing the cobalt-zinc bimetallic organic framework to be more stably anchored on the surface of the mesoporous silica. Octyltrimethoxysilane can rapidly hydrolyze at room temperature and covalently react with the mesoporous silica, grafting long hydrophobic octyl chains onto the surface of the mesoporous silica, thereby enhancing the hydrophobicity of the mesoporous silica and improving the hydrophobic properties of the metal catalyst.
[0016] 2. The metal catalyst of the present invention loads tri(pentafluorophenyl)borane onto modified silica. On the one hand, the strong Lewis acid center boron atom in tri(pentafluorophenyl)borane can form a coordination bond or a covalent bond with the silanol group on the surface of mesoporous silica, promote the physical or chemical adsorption capacity of tri(pentafluorophenyl)borane and mesoporous silica, reduce the self-aggregation of tri(pentafluorophenyl)borane, promote the exposure of active sites, and improve the catalytic efficiency of the metal catalyst. On the other hand, tri(pentafluorophenyl)borane is difficult to recycle in the reaction solution. After loading, it can be recovered by simple filtration or centrifugation, improve the utilization rate of tri(pentafluorophenyl)borane, and then reduce the application cost of the metal catalyst. In addition, tri(pentafluorophenyl)borane can induce a ring-opening reaction at low temperatures, thereby reducing the energy consumption of polyether polyol synthesis, in line with the green synthesis concept.
[0017] 3. The metal catalyst of the present invention introduces a cobalt-zinc bimetallic organic framework. On the one hand, the rigid coordination of the zinc ions in the cobalt-zinc bimetallic organic framework can prevent the oxidation of the cobalt ions, thereby preventing the metal catalyst activity from decreasing. Because the zinc ions have Lewis acidity, they synergistically activate the epoxy monomer with tris(pentafluorophenyl)borane, inhibiting the chain transfer reaction, narrowing the product relative molecular mass distribution, reducing the degree of unsaturation, and promoting the catalytic efficiency of the metal catalyst. On the other hand, the redox activity of the cobalt ions in the cobalt-zinc bimetallic organic framework can promote electron transfer and accelerate the formation of high molecular weight polymers. In addition, the hydrophobic chlorine atoms in the metal organic framework can increase the stability of the crystal framework, thereby improving the stability of the metal catalyst. DETAILED DESCRIPTION
[0018] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.
[0019] In the following examples, the CAS number of γ-aminopropyltriethoxysilane is 919-30-2; the CAS number of octyltrimethoxyborane is 3069-40-7; the CAS number of tris(pentafluorophenyl)borane is 1109-15-5; the CAS number of N,N-dimethylformamide is 15175-63-0; the CAS number of ethanol is 64-17-5; the CAS number of toluene is 108-88-3; the CAS number of cobalt chloride hexahydrate is 7791-13-1; the CAS number of zinc chloride is 7646-85-7; the CAS number of 2,5-dichloroterephthalic acid is 13799-90-1; and the mesoporous silica is SBA-15, CAS number 7631-86-9, with a pore size of 6-10 nm.
[0020] Example 1: A method for preparing a metal catalyst for preparing polyether polyols: S1: 10 parts of mesoporous silica were vacuum dried at 100° C. for 2 h to remove surface adsorbed water; S2: 10 parts of mesoporous silica were placed in an ethanol-water solution and ultrasonically dispersed for 30 minutes. 5 parts of γ-aminopropyltriethoxysilane were then added, and the mixture was heated to 80°C and refluxed under a nitrogen atmosphere for 20 hours. After the reaction, the mixture was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain amino-modified mesoporous silica. S3: 10 parts of amino-modified mesoporous silica were placed in a toluene solution and ultrasonically dispersed for 30 minutes. 2 parts of octyltrimethoxyborane were then added, and the solution was heated to 60°C and refluxed under a nitrogen atmosphere for 8 hours. After the reaction, the solution was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain modified mesoporous silica. S4: 10 parts of modified mesoporous silica and 10 parts of tris(pentafluorophenyl)borane were placed on a Schlenk apparatus and mixed, and then added to a mixture of 10 parts of toluene and 2 parts of deionized water. The mixture was ultrasonically dispersed for 30 minutes, heated to 90°C, and refluxed under a nitrogen atmosphere for 72 hours. After the reaction, the mixture was washed with toluene several times and dried in vacuo at 80°C to obtain tris(pentafluorophenyl)borane-modified mesoporous silica. S5: Add 10 parts of N,N-dimethylformamide and 10 parts of ethanol into a beaker and stir to mix. Then add 10 parts of tris(pentafluorophenyl)borane-modified mesoporous silica, 1 part of hydrated cobalt chloride, 0.8 parts of zinc chloride and 0.3 parts of 2,5-dichloroterephthalic acid. After fully dissolving, add 0.3 parts of fluoroboric acid, ultrasonically disperse for 30 minutes, heat to 100°C and react for 20 hours. After the reaction, wash with anhydrous ethanol several times and vacuum dry at 80°C to obtain a metal catalyst.
[0021] Example 2: A method for preparing a metal catalyst for preparing polyether polyols: S1: 10 parts of mesoporous silica were vacuum dried at 100° C. for 2 h to remove surface adsorbed water; S2: 10 parts of mesoporous silica were placed in an ethanol-water solution and ultrasonically dispersed for 30 minutes. 7 parts of γ-aminopropyltriethoxysilane were then added, and the mixture was heated to 90°C and refluxed under a nitrogen atmosphere for 22 hours. After the reaction, the mixture was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain amino-modified mesoporous silica. S3: 10 parts of amino-modified mesoporous silica were placed in a toluene solution and ultrasonically dispersed for 30 minutes. 3 parts of octyltrimethoxyborane were then added, and the solution was heated to 70°C and refluxed under a nitrogen atmosphere for 10 hours. After the reaction, the solution was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain modified mesoporous silica. S4: 10 parts of modified mesoporous silica and 10 parts of tris(pentafluorophenyl)borane were placed on a Schlenk apparatus and mixed, and then added to a mixture of 10 parts of toluene and 2 parts of deionized water. The mixture was ultrasonically dispersed for 30 minutes, heated to 90°C, and refluxed under a nitrogen atmosphere for 72 hours. After the reaction, the mixture was washed with toluene several times and dried in vacuo at 80°C to obtain tris(pentafluorophenyl)borane-modified mesoporous silica. S5: Add 10 parts of N,N-dimethylformamide and 10 parts of ethanol into a beaker and stir to mix. Then add 10 parts of tris(pentafluorophenyl)borane-modified mesoporous silica, 1 part of hydrated cobalt chloride, 0.8 parts of zinc chloride and 0.3 parts of 2,5-dichloroterephthalic acid. After fully dissolving, add 0.3 parts of fluoroboric acid, ultrasonically disperse for 30 minutes, heat to 100°C and react for 20 hours. After the reaction, wash with anhydrous ethanol several times and vacuum dry at 80°C to obtain a metal catalyst.
[0022] Example 3: A method for preparing a metal catalyst for preparing polyether polyols: S1: 10 parts of mesoporous silica were vacuum dried at 100° C. for 2 h to remove surface adsorbed water; S2: 10 parts of mesoporous silica were placed in an ethanol-water solution and ultrasonically dispersed for 30 minutes. 8 parts of γ-aminopropyltriethoxysilane were then added. The mixture was heated to 100°C and refluxed under a nitrogen atmosphere for 24 hours. After the reaction, the mixture was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain amino-modified mesoporous silica. S3: 10 parts of amino-modified mesoporous silica were placed in a toluene solution and ultrasonically dispersed for 30 minutes. 4 parts of octyltrimethoxyborane were then added, and the solution was heated to 80°C and refluxed under a nitrogen atmosphere for 12 hours. After the reaction, the solution was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain modified mesoporous silica. S4: 10 parts of modified mesoporous silica and 10 parts of tris(pentafluorophenyl)borane were placed on a Schlenk apparatus and mixed, and then added to a mixture of 10 parts of toluene and 2 parts of deionized water. The mixture was ultrasonically dispersed for 30 minutes, heated to 90°C, and refluxed under a nitrogen atmosphere for 72 hours. After the reaction, the mixture was washed with toluene several times and dried in vacuo at 80°C to obtain tris(pentafluorophenyl)borane-modified mesoporous silica. S5: Add 10 parts of N,N-dimethylformamide and 10 parts of ethanol into a beaker and stir to mix. Then add 10 parts of tris(pentafluorophenyl)borane-modified mesoporous silica, 1 part of hydrated cobalt chloride, 0.8 parts of zinc chloride and 0.3 parts of 2,5-dichloroterephthalic acid. After fully dissolving, add 0.3 parts of fluoroboric acid, ultrasonically disperse for 30 minutes, heat to 100°C and react for 20 hours. After the reaction, wash with anhydrous ethanol several times and vacuum dry at 80°C to obtain a metal catalyst.
[0023] Example 4: A method for preparing a metal catalyst for preparing polyether polyols: S1: 10 parts of mesoporous silica were vacuum dried at 100° C. for 2 h to remove surface adsorbed water; S2: 10 parts of mesoporous silica were placed in an ethanol-water solution and ultrasonically dispersed for 30 minutes. 8 parts of γ-aminopropyltriethoxysilane were then added. The mixture was heated to 100°C and refluxed under a nitrogen atmosphere for 24 hours. After the reaction, the mixture was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain amino-modified mesoporous silica. S3: 10 parts of amino-modified mesoporous silica were placed in a toluene solution and ultrasonically dispersed for 30 minutes. 4 parts of octyltrimethoxyborane were then added, and the solution was heated to 80°C and refluxed under a nitrogen atmosphere for 12 hours. After the reaction, the solution was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain modified mesoporous silica. S4: 10 parts of modified mesoporous silica and 11 parts of tris(pentafluorophenyl)borane were placed on a Schlenk apparatus and mixed, and then added to a mixture of 10 parts of toluene and 2.5 parts of deionized water. Ultrasonic dispersion was performed for 30 minutes, and the mixture was heated to 100°C and refluxed under a nitrogen atmosphere for 72 hours. After the reaction, the mixture was washed with toluene several times and dried in vacuo at 80°C to obtain tris(pentafluorophenyl)borane-modified mesoporous silica. S5: Add 10 parts of N,N-dimethylformamide and 10 parts of ethanol into a beaker and stir to mix. Then add 10 parts of tris(pentafluorophenyl)borane-modified mesoporous silica, 1 part of hydrated cobalt chloride, 0.8 parts of zinc chloride and 0.3 parts of 2,5-dichloroterephthalic acid. After fully dissolving, add 0.3 parts of fluoroboric acid, ultrasonically disperse for 30 minutes, heat to 100°C and react for 20 hours. After the reaction, wash with anhydrous ethanol several times and vacuum dry at 80°C to obtain a metal catalyst.
[0024] Example 5: A method for preparing a metal catalyst for preparing polyether polyols: S1: 10 parts of mesoporous silica were vacuum dried at 100° C. for 2 h to remove surface adsorbed water; S2: 10 parts of mesoporous silica were placed in an ethanol-water solution and ultrasonically dispersed for 30 minutes. 8 parts of γ-aminopropyltriethoxysilane were then added. The mixture was heated to 100°C and refluxed under a nitrogen atmosphere for 24 hours. After the reaction, the mixture was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain amino-modified mesoporous silica. S3: 10 parts of amino-modified mesoporous silica were placed in a toluene solution and ultrasonically dispersed for 30 minutes. 4 parts of octyltrimethoxyborane were then added, and the solution was heated to 80°C and refluxed under a nitrogen atmosphere for 12 hours. After the reaction, the solution was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain modified mesoporous silica. S4: 10 parts of modified mesoporous silica and 12 parts of tris(pentafluorophenyl)borane were placed on a Schlenk apparatus and mixed, and then added to a mixture of 10 parts of toluene and 3 parts of deionized water. The mixture was ultrasonically dispersed for 30 minutes, heated to 110°C, and refluxed under a nitrogen atmosphere for 72 hours. After the reaction, the mixture was washed with toluene several times and dried in vacuo at 80°C to obtain tris(pentafluorophenyl)borane-modified mesoporous silica. S5: Add 10 parts of N,N-dimethylformamide and 10 parts of ethanol into a beaker and stir to mix. Then add 10 parts of tris(pentafluorophenyl)borane-modified mesoporous silica, 1 part of hydrated cobalt chloride, 0.8 parts of zinc chloride and 0.3 parts of 2,5-dichloroterephthalic acid. After fully dissolving, add 0.3 parts of fluoroboric acid, ultrasonically disperse for 30 minutes, heat to 100°C and react for 20 hours. After the reaction, wash with anhydrous ethanol several times and vacuum dry at 80°C to obtain a metal catalyst.
[0025] Example 6: A method for preparing a metal catalyst for preparing polyether polyols: S1: 10 parts of mesoporous silica were vacuum dried at 100° C. for 2 h to remove surface adsorbed water; S2: 10 parts of mesoporous silica were placed in an ethanol-water solution and ultrasonically dispersed for 30 minutes. 8 parts of γ-aminopropyltriethoxysilane were then added. The mixture was heated to 100°C and refluxed under a nitrogen atmosphere for 24 hours. After the reaction, the mixture was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain amino-modified mesoporous silica. S3: 10 parts of amino-modified mesoporous silica were placed in a toluene solution and ultrasonically dispersed for 30 minutes. 4 parts of octyltrimethoxyborane were then added, and the solution was heated to 80°C and refluxed under a nitrogen atmosphere for 12 hours. After the reaction, the solution was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain modified mesoporous silica. S4: 10 parts of modified mesoporous silica and 12 parts of tris(pentafluorophenyl)borane were placed on a Schlenk apparatus and mixed, and then added to a mixture of 10 parts of toluene and 3 parts of deionized water. The mixture was ultrasonically dispersed for 30 minutes, heated to 110°C, and refluxed under a nitrogen atmosphere for 72 hours. After the reaction, the mixture was washed with toluene several times and dried in vacuo at 80°C to obtain tris(pentafluorophenyl)borane-modified mesoporous silica. S5: Add 50 parts of N,N-dimethylformamide and 20 parts of ethanol into a beaker and stir to mix. Then add 10 parts of tris(pentafluorophenyl)borane-modified mesoporous silica, 1.3 parts of hydrated cobalt chloride, 1 part of zinc chloride and 0.7 parts of 2,5-dichloroterephthalic acid. After fully dissolving, add 0.4 parts of fluoroboric acid, ultrasonically disperse for 30 minutes, heat to 110°C and react for 22 hours. After the reaction is completed, wash with anhydrous ethanol several times and vacuum dry at 80°C to obtain a metal catalyst.
[0026] Example 7: A method for preparing a metal catalyst for preparing polyether polyols: S1: 10 parts of mesoporous silica were vacuum dried at 100° C. for 2 h to remove surface adsorbed water; S2: 10 parts of mesoporous silica were placed in an ethanol-water solution and ultrasonically dispersed for 30 minutes. 8 parts of γ-aminopropyltriethoxysilane were then added. The mixture was heated to 100°C and refluxed under a nitrogen atmosphere for 24 hours. After the reaction, the mixture was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain amino-modified mesoporous silica. S3: 10 parts of amino-modified mesoporous silica were placed in a toluene solution and ultrasonically dispersed for 30 minutes. 4 parts of octyltrimethoxyborane were then added, and the solution was heated to 80°C and refluxed under a nitrogen atmosphere for 12 hours. After the reaction, the solution was washed several times with anhydrous ethanol and dried in vacuo at 80°C to obtain modified mesoporous silica. S4: 10 parts of modified mesoporous silica and 12 parts of tris(pentafluorophenyl)borane were placed on a Schlenk apparatus and mixed, and then added to a mixture of 10 parts of toluene and 3 parts of deionized water. The mixture was ultrasonically dispersed for 30 minutes, heated to 110°C, and refluxed under a nitrogen atmosphere for 72 hours. After the reaction, the mixture was washed with toluene several times and dried in vacuo at 80°C to obtain tris(pentafluorophenyl)borane-modified mesoporous silica. S5: Add 100 parts of N,N-dimethylformamide and 30 parts of ethanol into a beaker and stir to mix. Then add 10 parts of tris(pentafluorophenyl)borane-modified mesoporous silica, 1.5 parts of hydrated cobalt chloride, 1.2 parts of zinc chloride and 1 part of 2,5-dichloroterephthalic acid. After fully dissolving, add 0.5 parts of fluoroboric acid, ultrasonically disperse for 30 minutes, heat to 120°C and react for 24 hours. After the reaction is completed, wash with anhydrous ethanol several times and vacuum dry at 80°C to obtain a metal catalyst.
[0027] Comparative Example 1: A preparation method of a metal catalyst for preparing a polyether polyol: S2: 10 parts of mesoporous silica were placed in an ethanol aqueous solution and ultrasonically dispersed for 30 min, 40 parts of γ-aminopropyl triethoxysilane was added, heated to 100°C, and refluxed under a nitrogen atmosphere for 24 h. After the reaction was completed, the product was washed with anhydrous ethanol multiple times and vacuum dried at 80°C to obtain aminated mesoporous silica. The remaining steps were the same as in Example 7.
[0028] Comparative Example 2: A preparation method of a metal catalyst for preparing a polyether polyol: S3: 10 parts of aminated mesoporous silica were placed in a toluene solution and ultrasonically dispersed for 30 min, 0.01 parts of octyl trimethoxysilane was added, heated to 80°C, and refluxed under a nitrogen atmosphere for 12 h. After the reaction was completed, the product was washed with anhydrous ethanol multiple times and vacuum dried at 80°C to obtain modified mesoporous silica. The remaining steps were the same as in Example 7.
[0029] Comparative Example 3: A preparation method of a metal catalyst for preparing a polyether polyol: S4: 10 parts of modified mesoporous silica and 12 parts of tris(pentafluorophenyl)borane were mixed in a Schlenk device, then 10 parts of toluene was added, ultrasonically dispersed for 30 min, heated to 110°C, and refluxed under a nitrogen atmosphere for 72 h. After the reaction was completed, the product was washed with toluene multiple times and vacuum dried at 80°C to obtain tris(pentafluorophenyl)borane modified mesoporous silica. The remaining steps were the same as in Example 7.
[0030] Comparative Example 4: A preparation method of a metal catalyst for preparing a polyether polyol: S5: 100 parts of N,N-dimethylformamide and 30 parts of ethanol were added to a beaker and stirred to mix, then 10 parts of tris(pentafluorophenyl)borane modified mesoporous silica, 1.5 parts of hydrated cobalt chloride, and 1 part of 2,5-dichloro-p-xylenic acid were added, dissolved, 0.5 parts of fluoroboric acid was added, ultrasonically dispersed for 30 min, heated to 120°C, and reacted for 24 h. After the reaction was completed, the product was washed with anhydrous ethanol multiple times and vacuum dried at 80°C to obtain a metal catalyst. The remaining steps were the same as in Example 7.
[0031] Detection test: In a glove box, 0.1 g of the sample of the example or comparative example prepared in the application and 30 ml of propylene oxide were added to an oven-dried magnetic solvent storage bottle, sealed, and then placed in a 70°C water bath for 4 h. After the reaction was completed, the product was collected and analyzed. 19 F-NMR spectroscopy was used to analyze the primary hydroxyl molar fraction of the polyol.
[0032] The experimental results are shown in the following table:
[0033] Conclusion: By adjusting the distribution ratio of each component of the metal catalyst, the content of primary hydroxyl groups in the catalytic synthesis of polyether polyols can be increased.
[0034] In Comparative Example 1, mesoporous silica was modified with an excess of γ-aminopropyltriethoxysilane, resulting in the formation of physical adsorption or siloxane oligomers by the excess γ-aminopropyltriethoxysilane on the surface of the mesoporous silica, blocking the pores, so that the metal organic framework can only be grafted on the surface of the mesoporous silica and cannot enter the pores, thereby reducing the effective loading amount. At the same time, the zinc ions and cobalt ions are surrounded by excessive amino groups, resulting in coordination supersaturation, which reduces the crystallinity of the metal organic framework and reduces the catalytic activity of the metal catalyst.
[0035] In Comparative Example 2, mesoporous silica was hydrophobically modified with a trace amount of octyltrimethoxyborane, which increased the number of hydrophilic hydroxyl groups exposed on the surface of the mesoporous silica. These hydroxyl groups competed with the hydrophobicity of the metal organic framework ligand 2,5-dichloroterephthalic acid, increasing the risk of metal organic framework agglomeration on the surface of the mesoporous silica, reducing the stability of the metal organic framework in the metal catalyst, and thus reducing the catalytic activity of the metal catalyst.
[0036] In Comparative Example 3, deionized water catalyst was not used in the process of silica-supported tri(pentafluorophenyl)borane, which reduced the content of tri(pentafluorophenyl)borane grafted to the silica surface. However, tri(pentafluorophenyl)borane can increase the content of primary hydroxyl groups in the polyether polyol product. Therefore, the catalytic activity of the synthesized metal catalyst was significantly reduced.
[0037] The metal catalyst in Comparative Example 4 only loads a cobalt metal-organic framework. Since the cobalt metal-organic framework is easily hydrolyzed in a humid environment, the stability of the metal-organic framework is reduced; at the same time, the synergistic effect between the metal-organic framework and tris(pentafluorophenyl)borane is reduced, the unsaturation of the catalytic product is increased, and the catalytic activity of the metal catalyst is reduced.
[0038] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.
Claims
1. A method for preparing a metal catalyst for preparing polyether polyols, characterized in that: S1: adding mesoporous silica to an ethanol aqueous solution containing γ-aminopropyltriethoxysilane, heating the mixture for reaction, washing, and drying to obtain amino-modified mesoporous silica; S2: adding amino-modified mesoporous silica to anhydrous ethanol containing octyltrimethoxysilane, heating for reaction, washing and drying to obtain modified mesoporous silica; S3: dissolving the modified mesoporous silica and tris(pentafluorophenyl)borane in toluene containing a deionized water catalyst, heating for reaction, washing, and drying to obtain tris(pentafluorophenyl)borane-modified mesoporous silica; S4: adding tris(pentafluorophenyl)borane-modified mesoporous silica, cobalt-zinc bimetallic precursor and 2,5-dichloroterephthalic acid to a mixed solvent, then adding fluoroboric acid catalyst, heating for reaction, washing and drying to obtain a metal catalyst.
2. The method for preparing a metal catalyst for preparing polyether polyol according to claim 1, wherein: In step S1, the mass ratio of mesoporous silica to γ-aminopropyltriethoxysilane is 1:(0.5-0.8), the reaction temperature is 80-100° C., and the reaction time is 20-24 h.
3. The method for preparing a metal catalyst for preparing polyether polyol according to claim 1, wherein: In step S2, the mass ratio of amino-modified mesoporous silica to octyltrimethoxysilane is 1:(0.2-0.4), the reaction temperature is 60-80° C., and the reaction time is 8-12 h.
4. The method for preparing a metal catalyst for preparing polyether polyol according to claim 1, wherein: In step S3, the mass ratio of modified mesoporous silica to tris(pentafluorophenyl)borane is 1:(1-1.2), the reaction temperature is 90-110° C., and the reaction time is 70-76 h.
5. The method for preparing a metal catalyst for preparing polyether polyol according to claim 1, wherein: In step S4, the cobalt-zinc bimetallic precursor is cobalt chloride hexahydrate and zinc chloride, and the mass ratio of tris(pentafluorophenyl)borane-modified mesoporous silica, cobalt chloride hexahydrate, zinc chloride and 2,5-dichloroterephthalic acid is 1:(0.1-0.15):(0.08-0.12):(0.03-0.1).
6. The method for preparing a metal catalyst for preparing polyether polyol according to claim 1, wherein: In step S4, the heating reaction temperature is 100-120° C., and the reaction time is 20-24 h.
7. The method for preparing a metal catalyst for preparing polyether polyol according to claim 1, wherein: In step S3, the mass ratio of toluene to deionized water catalyst is 1:(0.2-0.3).
8. The method for preparing a metal catalyst for preparing polyether polyol according to claim 1, wherein: In step S4, the concentration of the solution containing the fluoroboric acid catalyst is 3-5 wt %.
9. The method for preparing a metal catalyst for preparing polyether polyol according to claim 1, characterized in that: In step S4, the mixed solvent is N,N-dimethylformamide and ethanol, and the mass ratio of N,N-dimethylformamide to ethanol is (1-10):(1-3).
10. A metal catalyst for preparing polyether polyol according to any one of claims 1 to 9.