High-stability double-metal cyanide catalyst for synthesizing polyether polyol as well as preparation method and application of high-stability double-metal cyanide catalyst

Abstract

The invention relates to the technical field of polymer chemistry and catalysts, in particular to a high-stability double-metal cyanide catalyst for polyether polyol synthesis as well as a preparation method and application of the high-stability double-metal cyanide catalyst. According to the high-stability double-metal cyanide catalyst for polyether polyol synthesis, a complex system of the catalyst contains a stable protective agent, and the stable protective agent is an organic compound which simultaneously contains a benzene ring group and at least one functional group selected from an ester group and / or an ether bond in a molecular structure of the stable protective agent. According to the method, the post-treatment procedure of a traditional KOH method and the pre-polymerization seed production procedure of a DMC method are thoroughly omitted, the production process is shortened, the energy consumption is reduced, no waste salt is generated, and the economic and environment-friendly benefits are remarkable.

Description

Technical Field

[0001] This invention relates to the fields of polymer chemistry and catalyst technology, specifically to highly stable bimetallic cyanide catalysts for the synthesis of polyether polyols, their preparation methods, and applications. Background Technology

[0002] Polyether polyols are the core raw materials of the polyurethane industry, and their performance directly determines the quality of final products such as polyurethane foams, elastomers, and coatings. Polyether polyols are usually produced by ring-opening polymerization of initiators containing active hydrogen (such as polyols) and epoxy compounds (such as propylene oxide (PO) and ethylene oxide (EO)) under the action of a catalyst.

[0003] Currently, two main types of catalysts are used in industry. The first type is the traditional alkaline catalyst, such as potassium hydroxide (KOH). KOH can effectively catalyze the reaction of various alcohols, including glycerol and propylene glycol, with epoxides, and the technology is mature. However, its disadvantages are very prominent: 1) The amount of catalyst used is large, usually more than 0.1% of the initiator weight, resulting in an excessively alkaline reaction system; 2) Strong alkalinity easily triggers side reactions, such as the rearrangement of PO to generate allyl alcohol, resulting in high unsaturation of polyether products and affecting the performance of polyurethane; 3) After the reaction, the catalyst and its products (salts) must be removed through complex acid neutralization, filtration, distillation, and other processes. This not only increases equipment investment and production costs and prolongs the production cycle, but also generates a large amount of industrial waste salt, causing an environmental burden.

[0004] The second type is the highly efficient bimetallic cyanide (DMC) catalyst. DMC catalysts exhibit catalytic activity thousands of times higher than KOH, and their dosage is extremely low (typically at the 10-50 ppm level). Therefore, they remain directly in the product after the reaction, requiring no post-treatment. Furthermore, DMC catalysts result in fewer catalytic side reactions, leading to polyether products with extremely low unsaturation, narrow molecular weight distribution, and excellent product quality. These advantages make DMC catalysts a promising direction for polyether synthesis technology.

[0005] However, conventional DMC catalysts face a key technical bottleneck: they cannot be directly used to catalyze the polymerization reactions of small-molecule alcohol initiators such as glycerol, propylene glycol, and ethylene glycol. The fundamental reason lies in the fact that the active structure of DMC catalysts is a coordination complex, typically stabilized by organic complexing agents such as tert-butanol. When these catalysts come into direct contact with highly polar, polyhydroxy small-molecule alcohols like glycerol, these alcohols, through their strong coordination and solvation abilities, replace the original complexing agents, disrupting the crystalline complex structure of the DMC catalyst and leading to the decomposition and deactivation of its active sites. In actual production, this manifests as an indefinitely prolonged reaction induction period, or even complete non-reaction.

[0006] To circumvent this problem, existing technologies have to employ a compromise "two-step method": first, KOH catalyst is used to react glycerol to generate a low-molecular-weight prepolymer "seed," then after complex neutralization and purification to remove KOH, this "seed" is used as an initiator to add a DMC catalyst for subsequent chain extension reactions. This method is cumbersome and fails to fully utilize the potential of DMC catalysts to simplify the process.

[0007] Therefore, there is an urgent need in this field for a novel DMC catalyst that can overcome the instability in small molecule alcohols and achieve direct and efficient catalysis of basic initiators such as glycerol and propylene glycol, thereby completely simplifying the polyether production process. Summary of the Invention

[0008] To address the shortcomings of the existing technology, the present invention aims to provide a highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols. The introduced benzene-ring-containing ester ether compound forms a physical barrier on the catalyst surface through the large steric hindrance and hydrophobicity of the benzene ring. Simultaneously, the oxygen atoms of the ester group or ether bond form a moderately strong coordination with the metal ions at the catalyst's active center. This synergistic effect of "physical shielding" and "chemical anchoring" forms a stable protective layer, effectively resisting the attack of small molecule alcohols such as glycerol, maintaining the integrity of the catalyst complex structure, and thus ensuring its high catalytic activity.

[0009] Another objective of this invention is to provide a method for preparing a highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols, which completely eliminates the post-processing steps of the traditional KOH method and the prepolymerization and seed preparation steps of the DMC method, shortens the production process, reduces energy consumption, generates no waste salt, and has significant economic and environmental benefits.

[0010] A third objective of this invention is to provide an application of a highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols, used to directly catalyze the ring-opening polymerization reaction of a small molecule alcohol initiator containing active hydrogen with an epoxide compound to prepare polyether polyols.

[0011] This invention is achieved using the following technical solution: The highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols contains a stabilizing agent in its complex system. The stabilizing agent is an organic compound whose molecular structure simultaneously contains a benzene ring group and at least one functional group selected from ester groups and / or ether bonds.

[0012] Specifically, existing DMC catalysts are deactivated in small molecule alcohols such as glycerol because the strongly polar hydroxyl groups of glycerol replace the active sites of the catalyst (such as Zn). 2+This attack destroys the existing weak coordinating complexes (such as tert-butanol) on the crystal structure of the molecule. The present invention discovers that to resist this attack, a molecule with dual functions is needed: Physical shielding function: Due to their large steric hindrance and hydrophobicity, the benzene ring group in the molecule can form an effective physical barrier after being coordinated to the catalyst surface, like a "hydrophobic protective shield", which spatially prevents and repels a large number of highly polar glycerol molecules from rapidly approaching the core active site of the catalyst.

[0013] Chemical anchoring function: The oxygen atom in the ester group or ether bond of the molecule has a lone pair of electrons, which can bind to the metal ions (such as Zn) at the active site of the catalyst. 2+ A coordination bond is formed. The strength of this coordination bond is optimized so that it is strong enough to firmly anchor the benzene ring, which acts as a "protective shield," to the catalyst surface, preventing it from easily falling off; but not so strong that it will not "poison" or completely occupy the active site, thus preserving the pathway for reaction with the epoxide monomer.

[0014] The general chemical formula of the catalyst is: Zn3[Co(CN)6]2·xZnCl2·y(L1)·z(L2) Wherein, L1 is an organic complexing agent, L2 is the stabilizer and protectant mentioned above, and x, y, and z are molar coefficients.

[0015] This general formula is a well-known representation in the field of DMC catalysts, and its purpose is to explicitly place the innovative point (L2) of this invention within the component framework of existing DMC catalysts. In the general formula, Zn3[Co(CN)6]2 is the skeletal structure of the catalyst, xZnCl2 represents the second metal salt that exists in excess as the active center of the Lewis acid; y(L1) represents a conventional organic complexing agent (such as tert-butanol).

[0016] The stabilizer is selected from one or more of ethyl phenoxyacetate, butyl phenoxyacetate, ethylene glycol monophenyl ether acetate, diethylene glycol monophenyl ether, diethylene glycol phthalate, or 2-methoxyethyl benzoate.

[0017] The method for preparing the highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols includes the step of adding an organic complexing agent and the stabilizer to the bimetallic cyanide precipitate for complexation and stabilization treatment after the precipitate is formed.

[0018] The timing and content of this step are crucial. Introducing the stabilizer L2 during the "ripening" stage after the initial formation of catalyst crystals, rather than through simple physical mixing after catalyst preparation, allows L2 molecules to deeply and uniformly embed into the lattice defects and surface active sites forming within the catalyst. This "co-complexation-ripening" process results in a stronger chemical and physical bond between the stabilizer and the catalyst matrix, constructing a far more robust overall protective structure than surface adsorption. This deeply integrated structure is the fundamental guarantee for the catalyst's long-term stability in harsh glycerol environments.

[0019] Following the stabilization treatment step, the catalyst is further washed with an aqueous solution containing an organic complexing agent and the stabilizer.

[0020] After the catalyst precipitation is completed, it needs to be washed to remove impurity ions (such as K+) that are harmful to catalytic activity. + Cl - However, if washing is done with pure water or a solution containing only the conventional complexing agent L1, according to the principle of chemical equilibrium, the stabilizing protective agent L2, which has already been complexed into the catalyst structure, may dissociate and be lost, thereby weakening the stability of the final product. The method of this invention maintains a dynamic equilibrium by pre-adding a certain concentration of L2 to the washing solution, effectively suppressing the dissociation of L2 from the catalyst, thus effectively removing impurities while preserving the catalyst's intact protective structure to the greatest extent. This is an important process optimization to ensure the catalyst achieves optimal performance.

[0021] The application of the highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols involves using the catalyst to directly catalyze the ring-opening polymerization reaction between a small molecule alcohol initiator containing active hydrogen and an epoxide compound to prepare polyether polyols.

[0022] The small molecule alcohol initiator is selected from one or more of glycerol, propylene glycol, ethylene glycol, trimethylolpropane, or pentaerythritol.

[0023] The amount of catalyst used is 10-50 ppm based on the weight of the final polyether polyol product.

[0024] After the polymerization reaction is completed, the catalyst remains in the polyether polyol product, and no post-processing steps are required.

[0025] The active sites of conventional DMC catalysts (such as Zn3[Co(CN)6]2) are unsaturated coordinated metal ions (mainly Zn) exposed on the crystal surface. 2+To stabilize these highly reactive Lewis acid sites, organic complexing agents (L1) such as tert-butanol (t-BuOH) are typically introduced for coordination, forming a [Zn-O(H)-tBu] structure. However, t-BuOH reacts with Zn... 2+ The coordination bonds are relatively weak. When the catalyst enters a medium of small molecule alcohols such as glycerol (GL) or propylene glycol (PG), the hydroxyl concentration of these small molecule alcohols is extremely high and they are highly polar. With a strong solvation effect and stronger coordination ability, they will rapidly and massively replace t-BuOH and destroy the original crystal structure, leading to the collapse of the catalyst's microstructure and the deactivation of the active center.

[0026] The benzene ring-containing ester ether compound (stabilizing agent L2) introduced in this invention protects the active site of the catalyst through a "synergistic shielding and anchoring" mechanism: Steric hindrance and hydrophobic shielding: The benzene ring group in the compound is large and hydrophobic. After coordinating to the catalyst surface, it acts like a "protective umbrella," forming a hydrophobic steric hindrance layer outside the active site. This protective layer effectively repels and prevents highly polar glycerol molecules from approaching and attacking the core active site.

[0027] Moderate chemical anchoring: The oxygen atom within the ester group (-COO-) or ether bond (-O-) in the compound contains a lone pair of electrons, which can interact with Zn on the catalyst surface. 2+ A coordinate bond is formed. The strength of this coordinate bond is between that of the weakly coordinated t-BuOH and the strongly coordinated glycerol. It can firmly anchor the "protective umbrella" (benzene ring) to the active site to prevent it from falling off, while it will not "poison" the catalyst due to excessive coordination, so that the active site can still react with the epoxide (PO / EO).

[0028] In summary, the stabilizing agent L2 constructs a dynamic, semi-permeable protective layer outside the active site of the catalyst through the synergistic effect of different functional groups at both ends of its molecule. This protective layer effectively prevents the destructive attack of glycerol molecules, which act as initiators, but allows smaller, more reactive epoxide monomers to enter and polymerize, thereby achieving the goal of direct catalysis in small molecule alcohols.

[0029] The preparation method of this invention introduces the stabilizing protective agent L2 into the system during the catalyst crystal formation and growth stage through a "co-complexation-curing" step. This allows L2 molecules to be more deeply and uniformly embedded in the lattice defects and surface of the catalyst, forming a protective structure that is far more robust than simple physical mixing. The subsequent addition of L2 to the washing solution is to maintain a balanced L2 concentration while removing impurity ions, preventing the complexed L2 from dissociating and being lost during washing, thus ensuring the final product has optimal stability and activity.

[0030] Compared with the prior art, the beneficial effects of the present invention are: (1) The benzene ring-containing ester ether compounds introduced in this invention form a physical barrier on the catalyst surface through the large steric hindrance and hydrophobicity of the benzene ring, while the oxygen atoms of the ester group or ether bond form a moderately strong coordination with the metal ions of the catalyst active center. This synergistic effect of "physical shielding" and "chemical anchoring" forms a stable protective layer, effectively resisting the attack of small molecule alcohols such as glycerol, maintaining the integrity of the catalyst complex structure, and thus ensuring its high catalytic activity.

[0031] (2) The catalyst of this invention can directly catalyze the polymerization of inexpensive and basic small molecule alcohol initiators such as glycerol and propylene glycol, completely eliminating the post-processing steps of the traditional KOH method and the prepolymerization and seed preparation steps of the DMC method. The production process is shortened, energy consumption is reduced, no waste salt is generated, and the economic and environmental benefits are significant.

[0032] (3) This invention maintains the inherent advantages of DMC catalyst, and the polyether polyol obtained has extremely low unsaturation and narrow molecular weight distribution, providing high-quality raw materials for the preparation of downstream high-performance polyurethane products. Detailed Implementation

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] This invention provides a highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols. The complex system of the catalyst contains a stabilizing agent, which is an organic compound whose molecular structure simultaneously contains a benzene ring group and at least one functional group selected from ester groups and / or ether bonds.

[0035] In this invention, the catalyst is primarily a bimetallic cyanide, such as Zn3[Co(CN)6]2. To maintain its catalytic activity, its complex system typically contains an organic complexing agent L1 and a key stabilizing agent L2.

[0036] In this invention, the stabilizing agent L2 is preferably selected from one or more of ethyl phenoxyacetate, butyl phenoxyacetate, ethylene glycol monophenyl ether acetate, diethylene glycol monophenyl ether, diethylene glycol phthalate, or 2-methoxyethyl benzoate, more preferably ethyl phenoxyacetate or ethylene glycol monophenyl ether acetate. This invention does not impose any particular limitation on the source of the stabilizing agent; commercially available products of the above-mentioned compounds well known to those skilled in the art can be used. In this invention, the molar ratio of the stabilizing agent (L2) to the metal (e.g., Co) in the second metal cyanide salt of the catalyst is preferably 5:1 to 30:1, more preferably 8:1 to 15:1.

[0037] In this invention, the organic complexing agent L1 is preferably selected from one or more of tert-butanol, isopropanol, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether, and more preferably tert-butanol. This invention does not impose any special restrictions on the source of the organic complexing agent; commercially available products are acceptable. In this invention, the molar ratio of the organic complexing agent (L1) to the metal (such as Co) in the second metal cyanide salt of the catalyst is preferably 20:1 to 100:1, and more preferably 50:1 to 80:1.

[0038] The highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols provided by this invention significantly enhances the structural stability of the catalyst in highly polar small molecule alcohol initiators such as glycerol and propylene glycol by introducing a stabilizing protectant with a specific structure into the catalyst's complex system. This protectant works synergistically with the original organic complexing agent, preventing decomposition and deactivation. Therefore, this catalyst can directly catalyze the polymerization reaction of small molecule alcohol initiators with epoxides, resulting in polyether products with extremely low unsaturation and narrow molecular weight distribution. Furthermore, it requires very low catalyst dosage and eliminates the need for post-reaction processing, thus solving the problems of existing technologies.

[0039] Furthermore, the catalyst provided by this invention has high activity, short reaction induction period, and fast polymerization rate, which fundamentally simplifies the entire polyether production process, significantly reduces production costs and environmental pollution, and has significant industrial application value.

[0040] The present invention also provides a method for preparing the catalyst described in the above technical solution, comprising the following steps: a) React an aqueous solution of the first metal salt with an aqueous solution of the second metal cyanide salt to generate a bimetallic cyanide precipitate; b) Add an organic complexing agent (L1) and a stabilizer (L2) to the slurry containing precipitates, and stir and mature it at a certain temperature; c) The matured product is separated, washed and dried to obtain the final high-stability bimetallic cyanide catalyst product.

[0041] In this invention, the temperature of the curing step is preferably 40℃~70℃, more preferably 50℃~60℃; the curing time is preferably 0.5h~3h, more preferably 1h~2h.

[0042] In this invention, the washing step is preferably performed using an aqueous solution containing an organic complexing agent (L1) and a stabilizing agent (L2) to prevent the complex structure from being damaged or components from being lost during the washing process.

[0043] The preparation method provided by this invention is simple, has mild conditions, is easy to control, and is suitable for large-scale industrial production.

[0044] The present invention also provides an application of the catalyst described in the above technical solution, namely, using it to directly catalyze the ring-opening polymerization reaction of a small molecule alcohol initiator containing active hydrogen with an epoxy compound to prepare a polyether polyol.

[0045] In this invention, the small molecule alcohol initiator preferably includes one or more of glycerol, propylene glycol, ethylene glycol, trimethylolpropane, pentaerythritol, and diethylene glycol.

[0046] In this invention, the epoxy compound preferably includes propylene oxide (PO), ethylene oxide (EO), or a mixture thereof.

[0047] In this invention, the amount of catalyst used relative to the total weight of the final polyether polyol product is preferably 10-50 ppm, more preferably 20-40 ppm. The polymerization reaction temperature is preferably 110-150°C, more preferably 125-140°C.

[0048] The application solution provided by this invention achieves direct catalysis of small molecule alcohols, and the catalyst can remain directly in the product after the reaction without any post-processing steps, thus revolutionarily simplifying the polyether production process. Compared with the traditional KOH method and DMC two-step method, it has unparalleled advantages in terms of cost, efficiency, environmental protection and product quality.

[0049] The low-unsaturation polyether polyol prepared by this invention can be widely used in the preparation of high-performance polyurethane materials, including but not limited to high resilience (HR) flexible foam (for car seats, high-end furniture, mattresses), rigid foam (for thermal insulation materials), polyurethane elastomers, coatings, adhesives and sealants (CASE).

[0050] To further illustrate the present invention, the following embodiments are provided for detailed description. All raw materials used in the following embodiments of the present invention are commercially available products.

[0051] Example 1 Preparation of catalyst C-1: 41.0 g of ZnCl2 (0.3 mol, molar ratio to Co 30:1) was dissolved in 80 mL of distilled water. 3.3 g of K3[Co(CN)6] (0.01 mol) was dissolved in 40 mL of distilled water. The K3[Co(CN)6] solution was added dropwise to the vigorously stirred ZnCl2 solution over 30 minutes at 55 °C. Then, a mixture of 60 mL of t-BuOH (0.63 mol, molar ratio to Co 63:1) and 16 mL of ethyl phenoxyacetate (0.09 mol, molar ratio to Co 9:1) was added, and the mixture was aged at 55 °C for 1.5 hours. After filtration, the mixture was washed with an aqueous solution containing t-BuOH and ethyl phenoxyacetate, and dried under vacuum at 80 °C for 5 hours to obtain catalyst C-1.

[0052] Synthesis of polyether P-1: 70 g of glycerol and 0.09 g of catalyst C-1 (30 ppm based on 3000 g of product) were added to a 5 L reactor. After vacuum dehydration at 130 °C, 150 g of PO was added dropwise at 135 °C for activation, and the pressure decreased within 15 minutes. Subsequently, 2780 g of PO was uniformly introduced over 3 hours. After the reaction was completed, polyether polyol P-1 was obtained.

[0053] Example 2 Preparation of catalyst C-2: 13.7 g ZnCl2 (0.1 mol, molar ratio to Co 10:1) was weighed and dissolved in 30 mL distilled water. 3.3 g K3[Co(CN)6] (0.01 mol) was weighed and dissolved in 40 mL distilled water. The reaction was carried out at 40 °C. Then, a mixture of 19 mL t-BuOH (0.2 mol, molar ratio to Co 20:1) and 9 mL phenoxyethyl acetate (0.05 mol, molar ratio to Co 5:1) was added, and the mixture was aged at 40 °C for 3 hours. Subsequent steps were the same as in Example 1 to obtain catalyst C-2.

[0054] Synthesis of polyether P-2: 70 g of glycerol and 0.03 g of catalyst C-2 (10 ppm based on 3000 g of product) were added to a 5 L reactor. After vacuum dehydration at 130 °C, 150 g of PO was added dropwise at 140 °C for activation, and the pressure decreased within 30 minutes. Subsequently, 2780 g of PO was uniformly introduced over 4 hours. After the reaction was completed, polyether polyol P-2 was obtained.

[0055] Example 3 Preparation of catalyst C-3: 68.2 g of ZnCl2 (0.5 mol, molar ratio to Co 50:1) was weighed and dissolved in 120 mL of distilled water. 3.3 g of K3[Co(CN)6] (0.01 mol) was weighed and dissolved in 40 mL of distilled water. The reaction was carried out at 70 °C. Then, a mixture of 95 mL of t-BuOH (1.0 mol, molar ratio to Co 100:1) and 53 mL of ethyl phenoxyacetate (0.3 mol, molar ratio to Co 30:1) was added, and the mixture was aged at 70 °C for 0.5 hours. Subsequent steps were the same as in Example 1 to obtain catalyst C-3.

[0056] Synthesis of polyether P-3: 70 g of glycerol and 0.15 g of catalyst C-3 (50 ppm based on 3000 g of product) were added to a 5 L reactor. After vacuum dehydration at 130 °C, 150 g of PO was added dropwise at 120 °C for activation, and the pressure decreased within 10 minutes. Subsequently, 2780 g of PO was uniformly introduced over 2.5 hours. After the reaction was completed, polyether polyol P-3 was obtained.

[0057] Comparative Example 1 Preparation of catalyst C-Ref1: The preparation method is basically the same as in Example 1, but in the ripening step, instead of adding 16 mL of ethyl phenoxyacetate, an equal volume (16 mL) of t-BuOH is added, that is, a total of 76 mL of t-BuOH is added. Conventional DMC catalyst C-Ref1 is obtained.

[0058] Polyether synthesis attempt: Glycerol polymerization was carried out under the exact same conditions as in Example 1, using 0.09 g of catalyst C-Ref1. Results: After adding PO activator, the reactor pressure did not decrease after being kept at 135°C for more than 4 hours, indicating that the catalyst was deactivated and unable to initiate polymerization.

[0059] Comparative Example 2 Catalyst: Industrial-grade KOH.

[0060] Synthesis of polyether P-Ref2: 70g glycerol and 6.0g KOH (2000ppm based on 3000g product) were added to a 5L reactor. After dehydration at 110℃, 2930g PO was introduced at 120℃ for reaction. After the reaction was completed, the mixture was neutralized with phosphoric acid, and the generated potassium phosphate was removed by pressure filtration to obtain polyether polyol P-Ref2.

[0061] The performance test data of the polyether polyol products obtained in Examples 1-3 and Comparative Examples 1-2 are shown in Table 1.

[0062] Table 1: Performance test data of polyether polyol products obtained in Examples 1-3 and Comparative Examples 1-2

[0063] As shown in Table 1, Examples 1, 2, and 3 successfully catalyzed the polymerization of glycerol directly with short induction periods, indicating that the catalyst of this invention has a stable structure and high activity. In contrast, the conventional DMC catalyst in Comparative Example 1, lacking a stabilizing agent, was completely deactivated, proving that the stabilizing agent L2 is crucial for the direct catalysis of small molecule alcohols. Compared to the traditional KOH method in Comparative Example 2, the polyether unsaturation obtained in the examples of this invention is reduced by an order of magnitude. This represents a decisive improvement in quality. Furthermore, the process of this invention requires no post-processing, greatly simplifying the production process, reducing costs, and producing no waste salt emissions, making it environmentally friendly. The results of Examples 2 and 3 demonstrate that within the raw material ratio range defined by this invention, qualified high-performance catalysts and high-quality polyether products can be prepared. The catalysts with higher unsaturation values ​​exhibit higher activity and lower product unsaturation. The low-unsaturation polyether polyols prepared by this invention are particularly suitable for manufacturing high-performance polyurethane materials, such as high-resilience (HR) automotive seat foam, high-end furniture, mattresses, sound insulation materials, as well as polyurethane elastomers, coatings, adhesives, and sealants (CASE).

[0064] Preparation of high-resilience foam: Polyether polyol, TDI (toluene diisocyanate), water, catalyst and foam stabilizer are mixed according to the formula, allowed to foam freely at room temperature, and their physical properties are tested after curing.

[0065] Specifically, it includes the following steps: Component A premix: In a 500 mL plastic beaker, accurately weigh 100.0 part of the polyether polyol sample to be tested (e.g., weigh 200.00 g P-1).

[0066] Add 3.5 parts water (7.00 g), 1.0 part silicone foam stabilizer (Niax® Silicone L-620) (2.00 g), and 0.4 parts amine catalyst (Dabco® 33-LV) (0.80 g) in sequence.

[0067] Place the beaker under a high-speed stirrer and stir at 2000 rpm for 60 seconds to ensure that all components are mixed evenly, forming a milky white premix of component A.

[0068] Use an infrared thermometer to measure the temperature of the premix and ensure it is within the range of room temperature (25±1℃).

[0069] Foaming reaction: Place the prepared component A premix in a fume hood.

[0070] Accurately weigh the required amount of component B—TDI-80 / 20 (based on 200.00g of polyether in component A, 96.00g of TDI needs to be weighed).

[0071] Increase the mixer speed to 3000 rpm.

[0072] Quickly pour all the weighed TDI into the premix of component A at once, and start the stopwatch at the same time.

[0073] Stir at high speed for 5-7 seconds until the material begins to change color, then stop stirring immediately.

[0074] Quickly pour the well-mixed reaction solution into the pre-prepared foaming mold.

[0075] Curing and Sample Preparation: Allow the foam to expand and solidify freely in the mold. Allow it to stand at room temperature (25±2℃) for 24 hours for initial curing.

[0076] After 24 hours, the foam was removed from the mold and placed in an oven at 60°C for 4 hours of post-curing to ensure complete reaction.

[0077] The fully cured foam blocks were placed under standard laboratory conditions (temperature 23±2℃, relative humidity 50±5%) for at least 24 hours to adjust their condition.

[0078] Using a specialized foam cutter, standard-sized samples are cut from the foam core (avoiding the outer layer) for subsequent physical property testing (such as density, resilience, tear strength, compression set, etc.).

[0079] Application Examples 1-3: Foams F-1, F-2, and F-3 were prepared using the polyethers P-1, P-2, and P-3 obtained in the examples, respectively.

[0080] Application Comparative Example 1: Foam F-Ref2 was prepared using the polyether P-Ref2 obtained from Comparative Example 2.

[0081] The test data of the physical properties of the high-resilience polyurethane foam obtained from Application Examples 1-3 and Application Comparative Example 1 are shown in Table 2.

[0082] Table 2: Test data of physical properties of high-resilience polyurethane foam obtained from Application Examples 1-3 and Comparative Example 1

[0083] As shown in Table 2, the foam prepared from the polyether of this invention significantly outperforms the foam prepared from polyether prepared by the traditional KOH method in all key performance aspects. Resilience is a core indicator of high-resilience foam; the resilience of the product of this invention is much higher than that of the comparative example, providing superior comfort and support. Tear strength reflects the durability of the foam; the tear strength of the product of this invention is approximately 50% higher than that of the comparative example, indicating greater material toughness. Lower compression set indicates a stronger ability of the foam to recover its original shape after long-term compression. The compression set of the product of this invention is much lower than that of the comparative example, demonstrating better durability. The unsaturation degree of the polyether raw material is crucial in determining foam performance. This invention, by providing polyether with ultra-low unsaturation, directly translates into a significant improvement in the physical properties of the final polyurethane product, proving the extremely high industrial application value of this technology.

Claims

1. A highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols, characterized in that, The catalyst complex system includes a stabilizing agent, which is an organic compound whose molecular structure simultaneously contains a benzene ring group and at least one functional group selected from ester groups and / or ether bonds.

2. The highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols according to claim 1, characterized in that, The general chemical formula of the catalyst is: Zn3[Co(CN)6]2·xZnCl2·y(L1)·z(L2) Wherein, L1 is an organic complexing agent, L2 is the stabilizing agent according to claim 1, and x, y, and z are molar coefficients.

3. The highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols according to claim 1, characterized in that, The stabilizer is selected from one or more of ethyl phenoxyacetate, butyl phenoxyacetate, ethylene glycol monophenyl ether acetate, diethylene glycol monophenyl ether, diethylene glycol phthalate, or 2-methoxyethyl benzoate.

4. A method for preparing a highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols as described in any one of claims 1-3, characterized in that, The step of adding an organic complexing agent and the stabilizer to the bimetallic cyanide precipitate after it has been formed is to perform complexation and stabilization treatment.

5. The method for preparing the highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols according to claim 4, characterized in that, Following the stabilization treatment step, the catalyst is further washed with an aqueous solution containing an organic complexing agent and the stabilizer.

6. The application of the highly stable bimetallic cyanide catalyst according to any one of claims 1-3 for the synthesis of polyether polyols, characterized in that, The catalyst is used to directly catalyze the ring-opening polymerization reaction of a small molecule alcohol initiator containing active hydrogen with an epoxy compound to prepare a polyether polyol.

7. The application of the highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols according to claim 6, characterized in that, The small molecule alcohol initiator is selected from one or more of glycerol, propylene glycol, ethylene glycol, trimethylolpropane, or pentaerythritol.

8. The application of the highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols according to claim 6, characterized in that, The amount of catalyst used is 10-50 ppm based on the weight of the final polyether polyol product.

9. The application of the highly stable bimetallic cyanide catalyst for the synthesis of polyether polyols according to claim 6, characterized in that, After the polymerization reaction is completed, the catalyst remains in the polyether polyol product, and no post-processing steps are required.

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