Preparation method of high-catalytic-activity ethylene glycol antimony applied to PET (Polyethylene Terephthalate) production

Abstract

The invention discloses a preparation method of high-catalytic-activity ethylene glycol antimony applied to PET production, and relates to the technical field of ethylene glycol antimony. The preparation method comprises the following steps: uniformly mixing and stirring ethylene glycol and antimony trioxide; adding a crystal structure regulating agent, a surfactant and a synergistic catalyst; heating, stirring and reacting to generate liquid ethylene glycol antimony; filtering to obtain clear liquid ethylene glycol antimony; crystallizing, cooling and separating out crystals; separating out crystals and drying to obtain a finished product of ethylene glycol antimony; the crystal structure regulating agent is selected from at least one of metal organic compounds or metal salts; the surfactant is selected from at least one of a nonionic surfactant or a silane coupling agent; the synergistic catalyst is selected from phosphorus-containing organic compounds. Through combined use of the crystal structure regulating agent, the surfactant and the synergistic catalyst, the catalytic activity, the selectivity and the dispersity of ethylene glycol antimony are improved, and the stability and the reusability of the ethylene glycol antimony are improved.

Description

Technical Field

[0001] The invention relates to the technical field of ethylene glycol antimony, and in particular to a method for preparing ethylene glycol antimony with high catalytic activity used in PET production. Background Art

[0002] Antimony glycolate is a catalyst widely used in the production of polyethylene terephthalate (PET), primarily for catalyzing the esterification and polycondensation reactions of PET. Its preparation typically involves a high-temperature reaction of ethylene glycol and antimony trioxide in a reactor to produce liquid antimony glycolate. This is followed by filtration and impurity removal, crystallization and cooling, solid-liquid separation, and drying to produce the solid antimony glycolate product. However, conventional antimony glycolate has a relatively simple crystal structure and a low specific surface area, resulting in insufficient catalytic efficiency, low catalytic selectivity, and insufficient reusability in PET esterification and polycondensation reactions. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a method for preparing ethylene glycol antimony with high catalytic activity for use in PET production. The specific technical solution is as follows:

[0004] A method for preparing ethylene glycol antimony with high catalytic activity for use in PET production comprises the following steps:

[0005] a. In a reaction vessel, mix ethylene glycol and antimony trioxide, heat to 85-95°C and stir evenly;

[0006] b. adding at least one crystal structure modifier, at least one surfactant and at least one synergistic catalyst to the reaction system and stirring to mix uniformly;

[0007] c. Raise the temperature to 140-180°C and stir to react to generate liquid antimony glycol;

[0008] d. The reaction product was filtered to remove impurities to obtain a clear liquid antimony glycol;

[0009] e. The liquid antimony glycol is crystallized and cooled to precipitate antimony glycol crystals;

[0010] f. Separate the antimony glycol crystals and dry them to obtain a high catalytic activity antimony glycol finished product;

[0011] Wherein, the crystal structure regulator is selected from at least one of metal organic compounds or metal salts, and the mass of the crystal structure regulator is 0.01% to 0.08% of the mass of ethylene glycol; the surfactant is selected from at least one of non-ionic surfactants or silane coupling agents, and the mass of the surfactant is 0.05% to 0.5% of the mass of ethylene glycol; the synergistic catalyst is selected from phosphorus-containing organic compounds, and the mass of the synergistic catalyst is 0.005% to 0.05% of the mass of ethylene glycol.

[0012] Preferably:

[0013] The crystal structure regulator is at least one of titanate, magnesium acetate, and zinc acetate;

[0014] The surfactant is at least one of polyethylene glycol, polypropylene glycol, and a silane coupling agent;

[0015] The synergistic catalyst is at least one of triphenylphosphine and tributylphosphine.

[0016] Preferably, the process of adding the crystal structure modifier, surfactant and synergistic catalyst in step b specifically includes:

[0017] Add crystal structure modifier at 85-95°C and stir for 10-20 minutes;

[0018] Maintain the temperature, add surfactant, and stir for 15 to 25 minutes;

[0019] The temperature was lowered to 80°C, the synergistic catalyst was added, and the mixture was stirred for 5 to 15 minutes.

[0020] Preferably:

[0021] In step a, the mass ratio of ethylene glycol to antimony trioxide is 100:(1.5-2.5);

[0022] Deionized water is also added in step a, wherein the mass of the deionized water is 0.5% to 1.5% of the mass of the ethylene glycol;

[0023] In step c, the reaction time is 1 to 4 hours and the stirring speed is 200 to 400 rpm;

[0024] In step e, the crystallization cooling is performed at a cooling rate of 0.3 to 1.5° C. / min, and the temperature is cooled to 40 to 60° C., and a synergistic catalyst of 0.005% to 0.02% by weight of ethylene glycol is added during the cooling process as a crystal nucleation inducer;

[0025] In step f, the separation method is centrifugal separation, the centrifugal speed is 3000-5000 rpm, and the centrifugal time is 5-15 minutes; the drying method is vacuum drying, the drying temperature is 50-80° C., and the drying time is 3-8 hours.

[0026] Preferably:

[0027] The reaction vessel is protected by an inert gas in steps a, b and c, and the reaction pressure is controlled at 0.05-0.3 MPa;

[0028] In step d, the filtration and impurity removal uses a filter medium with a pore size of 0.1 to 1 μm.

[0029] Preferably:

[0030] The inert gas is nitrogen;

[0031] The filter medium is a ceramic membrane or a polypropylene membrane.

[0032] Preferably, the crystal structure regulator is at least one of silane-modified titanate and titanium-zirconium composite ester;

[0033] The preparation process of the silane-modified titanate comprises the following steps:

[0034] Add anhydrous ethanol to a reaction vessel, heat to 40-50°C, add deionized water and glacial acetic acid while stirring, and adjust the pH of the solution to 4.5-5.5 to form an acidic ethanol solution;

[0035] Maintain the temperature and slowly add the silane coupling agent while stirring;

[0036] Under nitrogen protection, slowly add tetrabutyl titanate dropwise. After the addition is complete, heat to 60-65°C and stir to react for 1-2 hours.

[0037] The reaction product is cooled to room temperature, and ethanol and low-boiling point by-products are removed by distillation under reduced pressure to obtain the product;

[0038] The preparation process of the titanium-zirconium composite ester comprises the following steps:

[0039] Add anhydrous isopropyl alcohol to a reaction vessel, heat to 50-55°C, and add acetylacetone while stirring to form a solvent system;

[0040] Maintaining the temperature, under nitrogen protection, slowly add tetrabutyl zirconate;

[0041] Add deionized water and stir for 3-7 minutes, then slowly add tetrabutyl titanate dropwise. After the addition is complete, heat to 70-75°C and stir for 2-3 hours.

[0042] The reaction product is cooled to room temperature, and is distilled under reduced pressure to remove isopropyl alcohol and low-boiling point by-products to obtain the product.

[0043] Preferably, the surfactant is functionalized polyethylene glycol, and the preparation process of the functionalized polyethylene glycol comprises the following steps:

[0044] Add polyethylene glycol and anhydrous toluene to a reaction vessel, heat to 80-85°C, and stir until the polyethylene glycol is completely dissolved;

[0045] Maintain the temperature, slowly add 4-aminobutyric acid and stir evenly;

[0046] Under nitrogen atmosphere, add PTSA, raise the temperature to 110-120°C, and react for 4-6 hours;

[0047] After the reaction is completed, cool to 50°C, add an equal volume of deionized water, stir evenly, and then separate and remove the aqueous phase;

[0048] The organic phase was dried over anhydrous sodium sulfate and distilled under reduced pressure to remove toluene to obtain the product.

[0049] Preferably, the surfactant is a composite silane coupling agent, and the preparation process of the composite silane coupling agent includes the following steps:

[0050] Add anhydrous ethanol and deionized water into the reaction vessel and stir to mix evenly at 25-30°C;

[0051] Slowly add silane coupling agent and PFOTES in sequence while stirring and mix well;

[0052] Raise the temperature to 50-60°C, control the pH of the solution system to 4-5, and continue stirring for 2 hours to form a composite silane network;

[0053] Cool to room temperature, let stand for 30 min, and remove the aqueous phase by separation;

[0054] The product is obtained by removing the residual ethanol by distillation under reduced pressure.

[0055] Preferably, the synergistic catalyst is a functionalized phosphine compound, and the preparation process of the functionalized phosphine compound comprises the following steps:

[0056] Add DMF solvent into the reaction vessel;

[0057] Add triphenylphosphine at 50-60°C and stir until completely dissolved;

[0058] Maintain the temperature, slowly add 2-chloromethylpyridine dropwise and stir evenly;

[0059] Add thiobenzoic acid and continue stirring for 40 minutes, then raise the temperature to 70-80°C, add tetrabutylammonium bromide and stir evenly;

[0060] Add sodium hydroxide solution dropwise to adjust the pH of the system to 7.0-7.5 and stir for 15 minutes;

[0061] The mixture was cooled to 40°C and allowed to stand for 30 min. After solid-liquid separation, the DMF solvent was removed by vacuum distillation to collect the crude product.

[0062] Recrystallize with ethanol 2 to 3 times the mass of the crude product and filter to obtain the recrystallized product;

[0063] The recrystallized product was placed in a vacuum drying oven and dried at 50°C for 3-4 hours.

[0064] The high catalytic activity ethylene glycol antimony prepared by the preparation method provided by the present invention and used in PET production has the following beneficial effects:

[0065] 1. By introducing crystal structure regulators and synergistic catalysts, the specific surface area of ethylene glycol antimony is increased, the rate of catalytic PET esterification and polycondensation reaction is improved, and the reaction time is shortened;

[0066] 2. The synergistic catalyst enhances the electron cloud density of ethylene glycol antimony through coordination, improves the selectivity of the catalyst in the PET polycondensation reaction, reduces the formation of by-products, and at the same time enhances the chemical stability of the catalyst and prolongs its service life;

[0067] 3. Surfactants improve the dispersibility and solubility of ethylene glycol antimony in ethylene glycol. DETAILED DESCRIPTION

[0068] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below. The description in this section is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention.

[0069] This embodiment provides a method for preparing ethylene glycol antimony with high catalytic activity for use in PET production, comprising the following steps:

[0070] a. In a reaction vessel, mix ethylene glycol and antimony trioxide, heat to 85-95°C and stir evenly.

[0071] b. Add at least one crystal structure modifier, at least one surfactant and at least one synergistic catalyst to the reaction system and stir to mix them evenly.

[0072] c. Raise the temperature to 140-180°C and stir to react to generate liquid antimony glycol.

[0073] d. Filter the reaction product to remove impurities and obtain clear liquid antimony glycol.

[0074] e. The liquid antimony glycol is crystallized and cooled to precipitate antimony glycol crystals.

[0075] f. Separate the antimony glycolate crystals and dry them to obtain the finished product of antimony glycolate with high catalytic activity.

[0076] Among them, the crystal structure regulator is selected from at least one of metal organic compounds or metal salts, and the mass of the crystal structure regulator is 0.01% to 0.08% of the mass of ethylene glycol; the surfactant is selected from at least one of non-ionic surfactants or silane coupling agents, and the mass of the surfactant is 0.05% to 0.5% of the mass of ethylene glycol; the synergistic catalyst is selected from phosphorus-containing organic compounds, and the mass of the synergistic catalyst is 0.005% to 0.05% of the mass of ethylene glycol.

[0077] Among them, metal organic compounds or metal salts can be used as crystal structure regulators to regulate the crystallization process of ethylene glycol antimony. Metal ions induce the formation of smaller crystal nuclei in the reaction system, reduce the crystal growth rate, and generate crystals with smaller particle size and higher specific surface area, thereby increasing the active site density of the catalyst and solving the problem of low specific surface area of traditional ethylene glycol antimony. Non-ionic surfactants or silane coupling agents are used as surfactants. They adsorb on the surface of antimony trioxide or ethylene glycol antimony particles, reduce the van der Waals force between particles, prevent agglomeration, improve the dispersibility of ethylene glycol antimony in ethylene glycol, and improve the contact efficiency of the catalyst in the PET reaction system. Phosphorus-containing organic compounds act as synergistic catalysts. Through the coordination effect between phosphorus atoms and antimony atoms, they enhance the electron cloud density of ethylene glycol antimony, reduce the reaction activation energy, enhance the catalytic activity, and improve the selectivity of the PET polycondensation reaction, reduce the generation of by-products, and enhance the chemical stability of the catalyst and extend its service life.

[0078] This embodiment systematically optimizes the catalyst preparation process through the synergistic effect of multiple components, addressing the issues of conventional antimony glycolate, such as its simple crystal structure and low specific surface area. The combined use of a crystal structure modifier, surfactant, and synergistic catalyst not only enhances the catalytic activity, selectivity, and dispersibility of antimony glycolate, but also significantly improves its stability and reusability.

[0079] The high catalytic activity ethylene glycol antimony prepared by the preparation method provided in this embodiment and used in PET production has the following characteristics:

[0080] Beneficial effects:

[0081] 1. By introducing crystal structure regulators and synergistic catalysts, the specific surface area of ethylene glycol antimony is increased, the rate of catalytic PET esterification and polycondensation reaction is improved, and the reaction time is shortened.

[0082] 2. The synergistic catalyst enhances the electron cloud density of ethylene glycol antimony through coordination, improves the selectivity of the catalyst in the PET polycondensation reaction, reduces the formation of by-products, and at the same time enhances the chemical stability of the catalyst and prolongs its service life.

[0083] 3. Surfactants improve the dispersibility and solubility of ethylene glycol antimony in ethylene glycol.

[0084] Further:

[0085] The crystal structure regulator is at least one of titanate, magnesium acetate and zinc acetate.

[0086] The surfactant is at least one of polyethylene glycol, polypropylene glycol and a silane coupling agent.

[0087] The synergistic catalyst is at least one of triphenylphosphine and tributylphosphine.

[0088] Furthermore, the process of adding the crystal structure modifier, surfactant and synergistic catalyst in step b specifically includes:

[0089] Add the crystal structure modifier at 85-95°C and stir for 10-20 minutes.

[0090] Maintain the temperature, add surfactant and stir for 15 to 25 minutes.

[0091] The temperature was lowered to 80°C, the synergistic catalyst was added, and the mixture was stirred for 5 to 15 minutes.

[0092] Further:

[0093] In step a, the mass ratio of ethylene glycol to antimony trioxide is 100:(1.5-2.5).

[0094] Deionized water is also added in step a, and the mass of the deionized water is 0.5% to 1.5% of the mass of the ethylene glycol.

[0095] In step c, the reaction time is 1 to 4 hours, and the stirring speed is 200 to 400 rpm.

[0096] In step e, the crystallization cooling temperature is cooled at a rate of 0.3 to 1.5° C. / min to 40 to 60° C., and a synergistic catalyst with a mass percentage of 0.005% to 0.02% of ethylene glycol is added during the cooling process as a crystal nucleation inducer.

[0097] In step f, the separation method is centrifugal separation, the centrifugal speed is 3000-5000 rpm, and the centrifugal time is 5-15 minutes; the drying method is vacuum drying, the drying temperature is 50-80° C., and the drying time is 3-8 hours.

[0098] Further:

[0099] Inert gas is introduced into the reaction vessel during steps a, b and c, and the reaction pressure is controlled at 0.05-0.3 MPa.

[0100] In step d, filtering and removing impurities uses a filter medium with a pore size of 0.1 to 1 μm.

[0101] Further:

[0102] The inert gas is nitrogen.

[0103] The filter medium is ceramic membrane or polypropylene membrane.

[0104] Furthermore, the crystal structure regulator is at least one of silane-modified titanate and titanium-zirconium composite ester.

[0105] The preparation process of silane-modified titanate includes the following steps:

[0106] Anhydrous ethanol is added to a reaction container and heated to 40-50° C. Deionized water and glacial acetic acid are added under stirring, and the pH of the solution is adjusted to 4.5-5.5 to form an acidic ethanol solution.

[0107] Maintain the temperature and slowly add the silane coupling agent while stirring.

[0108] Under nitrogen protection, tetrabutyl titanate was slowly added dropwise. After the addition was completed, the temperature was raised to 60-65° C. and the mixture was stirred for 1-2 hours.

[0109] The reaction product is cooled to room temperature, and ethanol and low-boiling point by-products are removed by reduced pressure distillation to obtain the product.

[0110] The preparation process of titanium-zirconium composite ester includes the following steps:

[0111] Anhydrous isopropyl alcohol is added to a reaction container, heated to 50-55° C., and acetylacetone is added under stirring to form a solvent system.

[0112] While maintaining the temperature, tetrabutyl zirconate was slowly added under nitrogen protection.

[0113] Deionized water was added and stirred for 3 to 7 minutes, and then tetrabutyl titanate was slowly added dropwise. After the addition was completed, the temperature was raised to 70 to 75° C. and the mixture was stirred and reacted for 2 to 3 hours.

[0114] The reaction product is cooled to room temperature, and is distilled under reduced pressure to remove isopropyl alcohol and low-boiling point by-products to obtain the product.

[0115] Furthermore, the surfactant is functionalized polyethylene glycol, and the preparation process of the functionalized polyethylene glycol includes the following steps:

[0116] Add polyethylene glycol and anhydrous toluene into a reaction vessel, heat to 80-85°C, and stir until the polyethylene glycol is completely dissolved.

[0117] Maintain the temperature, slowly add 4-aminobutyric acid and stir evenly.

[0118] Under nitrogen atmosphere, add PTSA, raise the temperature to 110-120°C, and react for 4-6 hours.

[0119] After the reaction, the mixture was cooled to 50° C., an equal volume of deionized water was added, stirred evenly, and the aqueous phase was removed by separation.

[0120] The organic phase was dried over anhydrous sodium sulfate and distilled under reduced pressure to remove toluene to obtain the product.

[0121] Furthermore, the surfactant is a composite silane coupling agent, and the preparation process of the composite silane coupling agent includes the following steps:

[0122] Add anhydrous ethanol and deionized water into a reaction container, and stir and mix them evenly at 25-30°C.

[0123] While stirring, slowly add silane coupling agent and PFOTES in sequence and mix well.

[0124] The temperature was raised to 50-60° C., the pH of the solution system was controlled at 4-5, and stirring was continued for 2 h to form a composite silane network.

[0125] The mixture was cooled to room temperature, allowed to stand for 30 min, and the aqueous phase was removed by separation.

[0126] The product is obtained by removing the residual ethanol by distillation under reduced pressure.

[0127] Furthermore, the synergistic catalyst is a functionalized phosphine compound, and the preparation process of the functionalized phosphine compound includes the following steps:

[0128] DMF solvent was added to the reaction vessel.

[0129] Add triphenylphosphine at 50-60°C and stir until completely dissolved.

[0130] While maintaining the temperature, slowly add 2-chloromethylpyridine dropwise and stir evenly.

[0131] Thiobenzoic acid was added and stirring was continued for 40 min. The temperature was then raised to 70-80°C and tetrabutylammonium bromide was added and stirred evenly.

[0132] Sodium hydroxide solution was added dropwise to adjust the pH of the system to 7.0-7.5, and stirred for 15 minutes.

[0133] The mixture was cooled to 40°C and allowed to stand for 30 min. After solid-liquid separation, the DMF solvent was removed by distillation under reduced pressure to collect the crude product.

[0134] Recrystallize with ethanol 2 to 3 times the mass of the crude product and filter to obtain a recrystallized product.

[0135] The recrystallized product was placed in a vacuum drying oven and dried at 50°C for 3-4 hours.

[0136] Specific examples are provided below. The provided examples may enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0137] Example 1

[0138] Add 1 kg of ethylene glycol to a 5 L stainless steel reactor, start stirring (350 rpm), introduce nitrogen (pressure 0.1 MPa), and heat to 90°C. Slowly add 20 g of antimony trioxide and stir for 30 minutes to ensure uniform dispersion. Add 10 g of deionized water and continue stirring for 10 minutes to form a stable suspension. Maintaining 90°C, add 0.3 g of tetrabutyl titanate and 0.2 g of magnesium acetate and stir for 15 minutes. Add 2.0 g of polyethylene glycol and 1.0 g of silane coupling agent and stir for 20 minutes. Cool to 80°C, add 0.2 g of triphenylphosphine and stir for 10 minutes.

[0139] Raise the temperature to 160°C, adjust the stirring speed to 300 rpm, and react for 2.5 hours to produce liquid antimony glycolate. Maintain a nitrogen atmosphere and control the reactor pressure at 0.15 MPa. Filter the reaction product through a 0.5 μm ceramic membrane to remove unreacted solids and impurities. Collect the clear filtrate and visually inspect its clarity to ensure no noticeable turbidity.

[0140] The filtrate was transferred to a crystallization tank, cooled to 50°C (cooling rate 0.8°C / min), 0.1 g of triphenylphosphine was added as a crystal nucleation inducer, and the mixture was stirred at 100 rpm. The mixture was then allowed to stand for 2 hours to precipitate antimony ethylene glycol crystals.

[0141] Use a centrifuge (4000 rpm, 10 min) to separate the solid and liquid and collect the ethylene glycol antimony crystals. Wash the crystals with 50 g of ethylene glycol to remove any residual surface materials. Dry the crystals in a vacuum drying oven at 65°C for 5 h to obtain the finished ethylene glycol antimony product. Weigh and record the yield.

[0142] Take 2.72g of ethylene glycol antimony sample, add 100mg of ethylene glycol, place in a 65°C constant temperature water bath, and stir for 20 minutes. Visually inspect the solution to see if it is colorless, transparent, and free of turbidity, and record the result.

[0143] The particle size distribution of antimony glycolate crystals was determined using a laser particle size analyzer. The sample was dispersed in ethylene glycol and ultrasonicated for 5 minutes. The average particle size (D50) and particle size distribution range were recorded.

[0144] In a 1L reactor, add 300g of terephthalic acid (PTA), 180g of ethylene glycol, and 0.15g of ethylene glycol antimony sample. Heat to 240℃, pressure 0.3MPa, react for 2h, and measure the esterification rate (determine the carboxyl content by titration). Calculate the esterification reaction rate constant (k, min -1 ).

[0145] The content of diethylene glycol (DEG), a by-product of the esterification reaction, was analyzed by gas chromatography and the DEG content (wt%) was calculated. The lower the DEG content, the higher the selectivity.

[0146] The ethylene glycol antimony sample was recovered (centrifugation, ethylene glycol washing, and vacuum drying at 65°C), and the above catalytic activity test was repeated three times. The esterification reaction rate constant was recorded each time, and the catalytic activity retention rate (%) was calculated.

[0147] Example 2

[0148] Add 200g of anhydrous ethanol (purity ≥99.7%) to a 500mL three-necked flask, heat to 45°C, and stir at 300rpm. Add 5g of deionized water and 0.5g of glacial acetic acid and adjust the pH of the solution to 5.0. Maintaining 45°C, slowly add 5g of a silane coupling agent (KH-550, purity ≥97%) and stir for 20 minutes to ensure uniform dispersion. Under nitrogen protection (pressure 0.05MPa), slowly add 10g of tetrabutyl titanate (TBT, purity ≥98%) dropwise for approximately 30 minutes. After the addition is complete, raise the temperature to 62°C and stir for 1.5 hours. Cool the reaction product to room temperature (25°C) and remove the ethanol and low-boiling byproducts by vacuum distillation using a rotary evaporator (vacuum 0.08MPa, 50°C). The resulting product is approximately 12g of silane-modified titanate, which is stored in a sealed container for later use.

[0149] Add 1 kg of ethylene glycol to a 5 L stainless steel reactor, start stirring (350 rpm), introduce nitrogen (pressure 0.1 MPa), and heat to 90°C. Slowly add 20 g of antimony trioxide and stir for 30 minutes to ensure uniform dispersion. Add 10 g of deionized water and continue stirring for 10 minutes to form a stable suspension. Maintaining 90°C, add 0.5 g of silane-modified titanate and stir for 15 minutes. Add 2.0 g of polyethylene glycol and 1.0 g of silane coupling agent and stir for 20 minutes. Cool to 80°C, add 0.2 g of triphenylphosphine, and stir for 10 minutes.

[0150] Raise the temperature to 160°C, adjust the stirring speed to 300 rpm, and react for 2.5 hours to produce liquid antimony glycolate. Maintain a nitrogen atmosphere and control the reactor pressure at 0.15 MPa. Filter the reaction product through a 0.5 μm ceramic membrane to remove unreacted solids and impurities. Collect the clear filtrate and visually inspect its clarity to ensure no noticeable turbidity.

[0151] The filtrate was transferred to a crystallization tank, cooled to 50°C (cooling rate 0.8°C / min), 0.1 g of triphenylphosphine was added as a crystal nucleation inducer, and the mixture was stirred at 100 rpm. The mixture was then allowed to stand for 2 hours to precipitate antimony ethylene glycol crystals.

[0152] Use a centrifuge (4000 rpm, 10 min) to separate the solid and liquid and collect the ethylene glycol antimony crystals. Wash the crystals with 50 g of ethylene glycol to remove any residual surface materials. Dry the crystals in a vacuum drying oven at 65°C for 5 h to obtain the finished ethylene glycol antimony product. Weigh and record the yield.

[0153] Take 2.72g of ethylene glycol antimony sample, add 100mg of ethylene glycol, place in a 65°C constant temperature water bath, and stir for 20 minutes. Visually inspect the solution to see if it is colorless, transparent, and free of turbidity, and record the result.

[0154] The particle size distribution of antimony glycolate crystals was determined using a laser particle size analyzer. The sample was dispersed in ethylene glycol and ultrasonicated for 5 minutes. The average particle size (D50) and particle size distribution range were recorded.

[0155] In a 1L reactor, add 300g of terephthalic acid (PTA), 180g of ethylene glycol, and 0.15g of ethylene glycol antimony sample. Heat to 240℃, pressure 0.3MPa, react for 2h, and measure the esterification rate (determine the carboxyl content by titration). Calculate the esterification reaction rate constant (k, min -1 ).

[0156] The content of diethylene glycol (DEG), a by-product of the esterification reaction, was analyzed by gas chromatography and the DEG content (wt%) was calculated. The lower the DEG content, the higher the selectivity.

[0157] The ethylene glycol antimony sample was recovered (centrifugation, ethylene glycol washing, and vacuum drying at 65°C), and the above catalytic activity test was repeated three times. The esterification reaction rate constant was recorded each time, and the catalytic activity retention rate (%) was calculated.

[0158] Example 3

[0159] Add 200g of anhydrous isopropyl alcohol (purity ≥99.7%) to a 500mL three-necked flask, heat to 52°C, and stir at 300rpm. Add 3g of acetylacetone (purity ≥99%) and stir for 10 minutes to form a homogeneous solvent system. Under nitrogen protection (pressure 0.05MPa), slowly add 8g of tetrabutyl zirconate (purity ≥98%) and stir for 20 minutes to ensure uniform dispersion. Add 5g of deionized water and stir for 5 minutes. Slowly add 10g of tetrabutyl titanate (TBT, purity ≥98%) dropwise over a period of approximately 30 minutes. After the addition is complete, raise the temperature to 72°C and stir the reaction for 2.5 hours. Cool the reaction product to room temperature (25°C) and remove the isopropyl alcohol and low-boiling byproducts by vacuum distillation using a rotary evaporator (vacuum 0.08MPa, 55°C). The product yields approximately 14g of titanium-zirconium complex ester, which is stored in a sealed container for later use.

[0160] Add 1 kg of ethylene glycol to a 5 L stainless steel reactor, start stirring (350 rpm), introduce nitrogen (pressure 0.1 MPa), and heat to 90°C. Slowly add 20 g of antimony trioxide and stir for 30 minutes to ensure uniform dispersion. Add 10 g of deionized water and continue stirring for 10 minutes to form a stable suspension. Maintaining 90°C, add 0.5 g of titanium-zirconium complex ester and stir for 15 minutes. Add 2.0 g of polyethylene glycol and 1.0 g of silane coupling agent and stir for 20 minutes. Cool to 80°C, add 0.2 g of triphenylphosphine and stir for 10 minutes.

[0161] Raise the temperature to 160°C, adjust the stirring speed to 300 rpm, and react for 2.5 hours to produce liquid antimony glycolate. Maintain a nitrogen atmosphere and control the reactor pressure at 0.15 MPa. Filter the reaction product through a 0.5 μm ceramic membrane to remove unreacted solids and impurities. Collect the clear filtrate and visually inspect its clarity to ensure no noticeable turbidity.

[0162] The filtrate was transferred to a crystallization tank, cooled to 50°C (cooling rate 0.8°C / min), 0.1 g of triphenylphosphine was added as a crystal nucleation inducer, and the mixture was stirred at 100 rpm. The mixture was then allowed to stand for 2 hours to precipitate antimony ethylene glycol crystals.

[0163] Use a centrifuge (4000 rpm, 10 min) to separate the solid and liquid and collect the ethylene glycol antimony crystals. Wash the crystals with 50 g of ethylene glycol to remove any residual surface materials. Dry the crystals in a vacuum drying oven at 65°C for 5 h to obtain the finished ethylene glycol antimony product. Weigh and record the yield.

[0164] Take 2.72g of ethylene glycol antimony sample, add 100mg of ethylene glycol, place in a 65°C constant temperature water bath, and stir for 20 minutes. Visually inspect the solution to see if it is colorless, transparent, and free of turbidity, and record the result.

[0165] The particle size distribution of antimony glycolate crystals was determined using a laser particle size analyzer. The sample was dispersed in ethylene glycol and ultrasonicated for 5 minutes. The average particle size (D50) and particle size distribution range were recorded.

[0166] In a 1L reactor, add 300g of terephthalic acid (PTA), 180g of ethylene glycol, and 0.15g of ethylene glycol antimony sample. Heat to 240℃, pressure 0.3MPa, react for 2h, and measure the esterification rate (determine the carboxyl content by titration). Calculate the esterification reaction rate constant (k, min -1 ).

[0167] The content of diethylene glycol (DEG), a by-product of the esterification reaction, was analyzed by gas chromatography and the DEG content (wt%) was calculated. The lower the DEG content, the higher the selectivity.

[0168] The ethylene glycol antimony sample was recovered (centrifugation, ethylene glycol washing, and vacuum drying at 65°C), and the above catalytic activity test was repeated three times. The esterification reaction rate constant was recorded each time, and the catalytic activity retention rate (%) was calculated.

[0169] Example 4

[0170] To a 500mL three-necked flask, add 100g of polyethylene glycol (PEG-400, purity ≥99%) and 200g of anhydrous toluene (purity ≥99.5%). Heat to 82°C, start stirring (300rpm), and stir for 30 minutes until the polyethylene glycol is completely dissolved. Maintaining 82°C, slowly add 5g of 4-aminobutyric acid (purity ≥98%) and stir for 20 minutes to ensure uniform mixing. Under nitrogen protection (pressure 0.05MPa), add 0.5g of p-toluenesulfonic acid (PTSA, purity ≥98%) as a catalyst. Raise the temperature to 115°C and react for 5 hours while stirring (250rpm). After the reaction is completed, cool to 50°C, add 200g of deionized water, stir for 10 minutes, and separate the layers and remove the aqueous phase. Dry the organic phase over 20g of anhydrous sodium sulfate for 12 hours and filter to remove the sodium sulfate. Toluene was removed by reduced pressure distillation using a rotary evaporator (vacuum degree 0.08 MPa, 60° C.) to obtain about 102 g of functionalized polyethylene glycol, which was stored in a sealed container for later use.

[0171] Add 1kg of ethylene glycol to a 5L stainless steel reactor, start stirring (350rpm), introduce nitrogen (pressure 0.1MPa), and heat to 90°C. Slowly add 20g of antimony trioxide and stir for 30min to ensure uniform dispersion. Add 10g of deionized water and continue stirring for 10min to form a stable suspension. Maintain 90°C, add 0.3g of tetrabutyl titanate and 0.2g of magnesium acetate, and stir for 15min. Add 2.0g of functionalized polyethylene glycol and 1.0g of silane coupling agent and stir for 20min. Cool to 80°C, add 0.2g of triphenylphosphine, and stir for 10min.

[0172] Raise the temperature to 160°C, adjust the stirring speed to 300 rpm, and react for 2.5 hours to produce liquid antimony glycolate. Maintain a nitrogen atmosphere and control the reactor pressure at 0.15 MPa. Filter the reaction product through a 0.5 μm ceramic membrane to remove unreacted solids and impurities. Collect the clear filtrate and visually inspect its clarity to ensure no noticeable turbidity.

[0173] The filtrate was transferred to a crystallization tank, cooled to 50°C (cooling rate 0.8°C / min), 0.1 g of triphenylphosphine was added as a crystal nucleation inducer, and the mixture was stirred at 100 rpm. The mixture was then allowed to stand for 2 hours to precipitate antimony ethylene glycol crystals.

[0174] Use a centrifuge (4000 rpm, 10 min) to separate the solid and liquid and collect the ethylene glycol antimony crystals. Wash the crystals with 50 g of ethylene glycol to remove any residual surface materials. Dry the crystals in a vacuum drying oven at 65°C for 5 h to obtain the finished ethylene glycol antimony product. Weigh and record the yield.

[0175] Take 2.72g of ethylene glycol antimony sample, add 100mg of ethylene glycol, place in a 65°C constant temperature water bath, and stir for 20 minutes. Visually inspect the solution to see if it is colorless, transparent, and free of turbidity, and record the result.

[0176] The particle size distribution of antimony glycolate crystals was determined using a laser particle size analyzer. The sample was dispersed in ethylene glycol and ultrasonicated for 5 minutes. The average particle size (D50) and particle size distribution range were recorded.

[0177] In a 1L reactor, add 300g of terephthalic acid (PTA), 180g of ethylene glycol, and 0.15g of ethylene glycol antimony sample. Heat to 240℃, pressure 0.3MPa, react for 2h, and measure the esterification rate (determine the carboxyl content by titration). Calculate the esterification reaction rate constant (k, min -1 ).

[0178] The content of diethylene glycol (DEG), a by-product of the esterification reaction, was analyzed by gas chromatography and the DEG content (wt%) was calculated. The lower the DEG content, the higher the selectivity.

[0179] The ethylene glycol antimony sample was recovered (centrifugation, ethylene glycol washing, and vacuum drying at 65°C), and the above catalytic activity test was repeated three times. The esterification reaction rate constant was recorded each time, and the catalytic activity retention rate (%) was calculated.

[0180] Example 5

[0181] Add 150g of anhydrous ethanol (purity ≥99.7%) and 50g of deionized water to a 500mL three-necked flask. Stir at 300rpm at 28°C and mix for 15 minutes until homogeneous. While stirring, slowly add 10g of a silane coupling agent (KH-550, purity ≥97%) and stir for 10 minutes. Add 5g of perfluorooctyltriethoxysilane (PFOTES, purity ≥98%) and stir for 20 minutes to ensure uniform mixing. Heat to 55°C and adjust the pH of the solution to 4.5 with glacial acetic acid. Continue stirring for 2 hours to form a composite silane network. Cool to room temperature (25°C), let stand for 30 minutes, and remove the aqueous phase after separation. Remove any residual ethanol by vacuum distillation using a rotary evaporator (vacuum 0.08MPa, 50°C) to obtain approximately 13g of the composite silane coupling agent, which is stored in a sealed container until further use.

[0182] Add 1 kg of ethylene glycol to a 5 L stainless steel reactor, start stirring (350 rpm), introduce nitrogen (pressure 0.1 MPa), and heat to 90°C. Slowly add 20 g of antimony trioxide and stir for 30 minutes to ensure uniform dispersion. Add 10 g of deionized water and continue stirring for 10 minutes to form a stable suspension. Maintain the temperature at 90°C, add 0.3 g of tetrabutyl titanate and 0.2 g of magnesium acetate, and stir for 15 minutes. Add 2.0 g of a composite silane coupling agent and 1.0 g of polyethylene glycol and stir for 20 minutes. Cool to 80°C, add 0.2 g of triphenylphosphine, and stir for 10 minutes. Heat to 160°C, adjust the stirring speed to 300 rpm, and react for 2.5 hours to produce liquid antimony glycol. Maintain nitrogen protection and control the reactor pressure at 0.15 MPa. Filter the reaction product through a 0.5 μm ceramic membrane to remove unreacted solids and impurities. The clear filtrate was collected and visually inspected for transparency, showing no obvious turbidity.

[0183] The filtrate was transferred to a crystallization tank, cooled to 50°C (cooling rate 0.8°C / min), 0.1 g of triphenylphosphine was added as a crystal nucleation inducer, and the mixture was stirred at 100 rpm. The mixture was then allowed to stand for 2 hours to precipitate antimony ethylene glycol crystals.

[0184] Use a centrifuge (4000 rpm, 10 min) to separate the solid and liquid and collect the ethylene glycol antimony crystals. Wash the crystals with 50 g of ethylene glycol to remove any residual surface materials. Dry the crystals in a vacuum drying oven at 65°C for 5 h to obtain the finished ethylene glycol antimony product. Weigh and record the yield.

[0185] Take 2.72g of ethylene glycol antimony sample, add 100mg of ethylene glycol, place in a 65°C constant temperature water bath, and stir for 20 minutes. Visually inspect the solution to see if it is colorless, transparent, and free of turbidity, and record the result.

[0186] The particle size distribution of antimony glycolate crystals was determined using a laser particle size analyzer. The sample was dispersed in ethylene glycol and ultrasonicated for 5 minutes. The average particle size (D50) and particle size distribution range were recorded.

[0187] In a 1L reactor, add 300g of terephthalic acid (PTA), 180g of ethylene glycol, and 0.15g of antimony glycolate sample. Heat to 240°C, pressure 0.3 MPa, and react for 2 hours. Determine the esterification rate (carboxyl group content by titration). Calculate the esterification reaction rate constant (k, min-1).

[0188] The content of diethylene glycol (DEG), a by-product of the esterification reaction, was analyzed by gas chromatography and the DEG content (wt%) was calculated. The lower the DEG content, the higher the selectivity.

[0189] The ethylene glycol antimony sample was recovered (centrifugation, ethylene glycol washing, and vacuum drying at 65°C), and the above catalytic activity test was repeated three times. The esterification reaction rate constant was recorded each time, and the catalytic activity retention rate (%) was calculated.

[0190] Example 6

[0191] Add 200g of N,N-dimethylformamide (DMF, purity ≥99.5%) to a 500mL three-necked flask and stir (300rpm). Heat to 55°C, add 10g of triphenylphosphine (TPP, purity ≥99%), and stir for 20 minutes until completely dissolved. Maintaining 55°C, slowly add 5g of 2-chloromethylpyridine (purity ≥98%) dropwise over approximately 15 minutes, stirring for 10 minutes to ensure uniformity. Add 3g of thiobenzoic acid (purity ≥98%) and stir for 40 minutes. Raise the temperature to 75°C, add 0.5g of tetrabutylammonium bromide (TBAB, purity ≥99%), and stir for 10 minutes. Add approximately 5mL of 1mol / L sodium hydroxide solution dropwise to adjust the pH to 7.2 and stir for 15 minutes. Cool to 40°C, let stand for 30 minutes, and perform solid-liquid separation using a centrifuge (3000rpm, 10 minutes), collecting the liquid portion. DMF was removed by vacuum distillation using a rotary evaporator (vacuum 0.08 MPa, 60°C) to obtain approximately 12 g of crude product. The crude product was dissolved in 30 g of ethanol (purity ≥ 99.7%), heated to 60°C, stirred to dissolve, and then slowly cooled to room temperature to precipitate crystals. The crystals were collected by filtration to obtain a recrystallized product. The recrystallized product was placed in a vacuum drying oven at 50°C for 3.5 hours at a vacuum of 0.085 MPa to obtain approximately 10 g of a functionalized phosphine compound, which was stored in a sealed container for later use.

[0192] Add 1kg of ethylene glycol to a 5L stainless steel reactor, start stirring (350rpm), introduce nitrogen (pressure 0.1MPa), and heat to 90°C. Slowly add 20g of antimony trioxide and stir for 30min to ensure uniform dispersion. Add 10g of deionized water and continue stirring for 10min to form a stable suspension. Maintain 90°C, add 0.3g of tetrabutyl titanate and 0.2g of magnesium acetate, and stir for 15min. Add 2.0g of polyethylene glycol and 1.0g of silane coupling agent and stir for 20min. Cool to 80°C, add 0.2g of functionalized phosphine compound, and stir for 10min.

[0193] Raise the temperature to 160°C, adjust the stirring speed to 300 rpm, and react for 2.5 hours to produce liquid antimony glycolate. Maintain a nitrogen atmosphere and control the reactor pressure at 0.15 MPa. Filter the reaction product through a 0.5 μm ceramic membrane to remove unreacted solids and impurities. Collect the clear filtrate and visually inspect its clarity to ensure no noticeable turbidity.

[0194] The filtrate was transferred to a crystallization tank, cooled to 50°C (cooling rate 0.8°C / min), 0.1 g of triphenylphosphine was added as a crystal nucleation inducer, and the mixture was stirred at 100 rpm. The mixture was then allowed to stand for 2 hours to precipitate antimony ethylene glycol crystals.

[0195] Use a centrifuge (4000 rpm, 10 min) to separate the solid and liquid and collect the ethylene glycol antimony crystals. Wash the crystals with 50 g of ethylene glycol to remove any residual surface materials. Dry the crystals in a vacuum drying oven at 65°C for 5 h to obtain the finished ethylene glycol antimony product. Weigh and record the yield.

[0196] Take 2.72g of ethylene glycol antimony sample, add 100mg of ethylene glycol, place in a 65°C constant temperature water bath, and stir for 20 minutes. Visually inspect the solution to see if it is colorless, transparent, and free of turbidity, and record the result.

[0197] The particle size distribution of antimony glycolate crystals was determined using a laser particle size analyzer. The sample was dispersed in ethylene glycol and ultrasonicated for 5 minutes. The average particle size (D50) and particle size distribution range were recorded.

[0198] In a 1L reactor, add 300g of terephthalic acid (PTA), 180g of ethylene glycol, and 0.15g of ethylene glycol antimony sample. Heat to 240℃, pressure 0.3MPa, react for 2h, and measure the esterification rate (determine the carboxyl content by titration). Calculate the esterification reaction rate constant (k, min -1 ).

[0199] The content of diethylene glycol (DEG), a by-product of the esterification reaction, was analyzed by gas chromatography and the DEG content (wt%) was calculated. The lower the DEG content, the higher the selectivity.

[0200] The ethylene glycol antimony sample was recovered (centrifugation, ethylene glycol washing, and vacuum drying at 65°C), and the above catalytic activity test was repeated three times. The esterification reaction rate constant was recorded each time, and the catalytic activity retention rate (%) was calculated.

[0201] Comparative Example 1

[0202] Add 1 kg of ethylene glycol to a 5 L stainless steel reactor, start stirring (350 rpm), introduce nitrogen (pressure 0.1 MPa), and heat to 90°C. Slowly add 20 g of antimony trioxide and stir for 30 minutes to ensure uniform dispersion. Add 10 g of deionized water and continue stirring for 10 minutes to form a stable suspension.

[0203] Raise the temperature to 160°C, adjust the stirring speed to 300 rpm, and react for 2.5 hours to produce liquid antimony glycolate. Maintain a nitrogen atmosphere and control the reactor pressure at 0.15 MPa. Filter the reaction product through a 0.5 μm ceramic membrane. Collect the clear filtrate and visually inspect its clarity; it should be free of noticeable turbidity.

[0204] The filtrate was transferred to a crystallization tank and cooled to 50°C (cooling rate 0.8°C / min). The mixture was allowed to stand for 2 hours to precipitate antimony glycolate crystals.

[0205] Use a centrifuge (4000 rpm, 10 min) to perform solid-liquid separation and collect the antimony ethylene glycol crystals. Place the crystals in a vacuum drying oven at 65° C. for 5 h to obtain the antimony ethylene glycol product, weigh it, and record the yield.

[0206] Take 2.72g of ethylene glycol antimony sample, add 100mg of ethylene glycol, place in a 65°C constant temperature water bath, and stir for 20 minutes. Visually inspect the solution to see if it is colorless, transparent, and free of turbidity, and record the result.

[0207] The particle size distribution of antimony glycolate crystals was determined using a laser particle size analyzer. The sample was dispersed in ethylene glycol and ultrasonicated for 5 minutes. The average particle size (D50) and particle size distribution range were recorded.

[0208] In a 1L reactor, add 300g of terephthalic acid (PTA), 180g of ethylene glycol, and 0.15g of ethylene glycol antimony sample. Heat to 240℃, pressure 0.3MPa, react for 2h, and measure the esterification rate (determine the carboxyl content by titration). Calculate the esterification reaction rate constant (k, min -1 ).

[0209] The content of diethylene glycol (DEG), a by-product of the esterification reaction, was analyzed by gas chromatography and the DEG content (wt%) was calculated. The lower the DEG content, the higher the selectivity.

[0210] The ethylene glycol antimony sample was recovered (centrifugation, ethylene glycol washing, and vacuum drying at 65°C), and the above catalytic activity test was repeated three times. The esterification reaction rate constant was recorded each time, and the catalytic activity retention rate (%) was calculated.

[0211] The experimental test data of antimony glycolate prepared in Examples 1 to 6 and the comparative example are shown in the following table:

[0212]

[0213] From the above data we can see that:

[0214] 1. The yields of Examples 1 to 6 (18.5 to 18.9 g) were all higher than those of the comparative example (18.2 g), indicating that the addition of auxiliary materials slightly increased the reaction conversion rate;

[0215] 2. Examples 1 to 6 and the comparative example all meet the quality standards (colorless and transparent, without turbidity);

[0216] 3. The average particle size of Examples 1 to 6 (2.4 to 2.8 μm) is significantly smaller than that of the comparative example (5.2 μm), and the distribution range is narrower, indicating that the excipients optimize the crystal structure and increase the specific surface area;

[0217] 4. Esterification reaction rate constants (0.042-0.047 min) of Examples 1-6 -1 ) are higher than the comparative example (0.032min -1 ), wherein Example 6 (0.047min -1 ) performed best, with an improvement of 46.9%, which was attributed to the strong coordination effect of the functionalized phosphine compound;

[0218] 5. The DEG content of Examples 1 to 6 (0.79 to 0.85 wt%) is lower than that of the comparative example (1.20 wt%), with Example 6 (0.79 wt%) being the lowest, indicating that the functionalized phosphine compound significantly improves the catalytic selectivity.

[0219] 6. The third catalytic activity retention rates of Examples 1 to 6 (90.5% to 91.5%) were much higher than those of the comparative example (78.1%), with Example 6 (91.5%) being the best, indicating that the functionalized phosphine compound improved the structural stability of antimony glycolate.

[0220] Principle description:

[0221] Metallic organic compounds or metal salts, as crystal structure modulators, can regulate the crystallization process of antimony glycolate. Metal ions induce the formation of finer nuclei in the reaction system, reducing the crystal growth rate and producing crystals with smaller particle size and higher specific surface area. This increases the active site density of the catalyst, resolving the low specific surface area problem of conventional antimony glycolate. Nonionic surfactants or silane coupling agents, as surfactants, adsorb onto the surface of antimony trioxide or antimony glycolate particles, reducing the van der Waals forces between the particles, preventing agglomeration, improving the dispersibility of antimony glycolate in ethylene glycol, and enhancing the contact efficiency of the catalyst in the PET reaction system. Phosphorus-containing organic compounds, acting as synergistic catalysts, enhance the electron cloud density of antimony glycolate through the coordination between phosphorus atoms and antimony atoms, reducing the reaction activation energy, improving catalytic activity, and enhancing the selectivity of the PET polycondensation reaction, reducing byproduct formation, while also enhancing the chemical stability of the catalyst and extending its service life. The synergistic effect of these multiple components systematically optimizes the catalyst preparation process by addressing the problems of conventional antimony glycolate, such as its simple crystal structure and low specific surface area. The combined use of crystal structure regulators, surfactants and synergistic catalysts not only enhances the catalytic activity, selectivity and dispersibility of ethylene glycol antimony, but also significantly improves its stability and reusability.

[0222] The principles and implementation methods of the present invention are described herein using specific examples. The description of the above embodiments is only intended to help understand the method and core ideas of the present invention. The above are only preferred implementation methods of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, and all of these should fall within the scope of protection of the present invention.

Claims

1. A method for preparing ethylene glycol antimony with high catalytic activity for use in PET production, characterized in that: The steps include: a) In a reaction vessel, mix ethylene glycol and antimony trioxide, raise the temperature to 85-95°C and stir evenly; b) adding at least one crystal structure modifier, at least one surfactant, and at least one synergistic catalyst to the reaction system, and stirring and mixing them uniformly; c) heating to 140-180° C. and stirring to react to generate liquid antimony glycol; d) filtering the reaction product to remove impurities to obtain clear liquid antimony glycol; e) crystallizing and cooling the liquid antimony glycol to separate out antimony glycol crystals; f) separating the antimony glycolate crystals and drying them to obtain a finished antimony glycolate product with high catalytic activity; Wherein, the crystal structure regulator is selected from at least one of metal organic compounds or metal salts, and the mass of the crystal structure regulator is 0.01% to 0.08% of the mass of ethylene glycol; the surfactant is selected from at least one of non-ionic surfactants or silane coupling agents, and the mass of the surfactant is 0.05% to 0.5% of the mass of ethylene glycol; the synergistic catalyst is selected from phosphorus-containing organic compounds, and the mass of the synergistic catalyst is 0.005% to 0.05% of the mass of ethylene glycol.

2. The preparation method according to claim 1, wherein: The crystal structure regulator is at least one of titanate, magnesium acetate, and zinc acetate; The surfactant is at least one of polyethylene glycol, polypropylene glycol, and a silane coupling agent; The synergistic catalyst is at least one of triphenylphosphine and tributylphosphine.

3. The preparation method according to claim 1, characterized in that The process of adding the crystal structure modifier, surfactant and synergistic catalyst in step b) specifically includes: Add crystal structure modifier at 85-95°C and stir for 10-20 minutes; Maintain the temperature, add surfactant, and stir for 15 to 25 minutes; The temperature was lowered to 80°C, the synergistic catalyst was added, and the mixture was stirred for 5 to 15 minutes.

4. The preparation method according to claim 1, wherein: In step a), the mass ratio of ethylene glycol to antimony trioxide is 100:(1.5-2.5); Deionized water is also added in step a), wherein the mass of the deionized water is 0.5% to 1.5% of the mass of the ethylene glycol; In step c), the reaction time is 1 to 4 hours and the stirring speed is 200 to 400 rpm; In step e), the crystallization cooling is performed at a cooling rate of 0.3 to 1.5° C. / min, and the temperature is cooled to 40 to 60° C., and a synergistic catalyst of 0.005% to 0.02% by weight of ethylene glycol is added during the cooling process as a crystal nucleation inducer; In step f), the separation method is centrifugal separation, the centrifugal speed is 3000-5000 rpm, and the centrifugal time is 5-15 minutes; the drying method is vacuum drying, the drying temperature is 50-80° C., and the drying time is 3-8 hours.

5. The preparation method according to claim 1, wherein: The reaction vessel is protected by an inert gas in steps a), b) and c), and the reaction pressure is controlled at 0.05-0.3 MPa; In step d), the filtering and impurity removal uses a filter medium with a pore size of 0.1 to 1 μm.

6. The preparation method according to claim 5, characterized in that: The inert gas is nitrogen; The filter medium is a ceramic membrane or a polypropylene membrane.

7. The preparation method according to any one of claims 1 to 6, characterized in that The crystal structure regulator is at least one of silane-modified titanate and titanium-zirconium composite ester; The preparation process of the silane-modified titanate comprises the following steps: Add anhydrous ethanol to a reaction vessel, heat to 40-50°C, add deionized water and glacial acetic acid while stirring, and adjust the pH of the solution to 4.5-5.5 to form an acidic ethanol solution; Maintain the temperature and slowly add the silane coupling agent while stirring; Under nitrogen protection, slowly add tetrabutyl titanate dropwise. After the addition is complete, heat to 60-65°C and stir to react for 1-2 hours. The reaction product is cooled to room temperature, and ethanol and low-boiling point by-products are removed by distillation under reduced pressure to obtain the product; The preparation process of the titanium-zirconium composite ester comprises the following steps: Add anhydrous isopropyl alcohol to a reaction vessel, heat to 50-55°C, and add acetylacetone while stirring to form a solvent system; Maintaining the temperature, under nitrogen protection, slowly add tetrabutyl zirconate; Add deionized water and stir for 3-7 minutes, then slowly add tetrabutyl titanate dropwise. After the addition is complete, heat to 70-75°C and stir for 2-3 hours. The reaction product is cooled to room temperature, and is distilled under reduced pressure to remove isopropyl alcohol and low-boiling point by-products to obtain the product.

8. The preparation method according to any one of claims 1 to 6, characterized in that The surfactant is functionalized polyethylene glycol, and the preparation process of the functionalized polyethylene glycol includes the following steps: Add polyethylene glycol and anhydrous toluene to a reaction vessel, heat to 80-85°C, and stir until the polyethylene glycol is completely dissolved; Maintain the temperature, slowly add 4-aminobutyric acid and stir evenly; Under nitrogen atmosphere, add PTSA, raise the temperature to 110-120°C, and react for 4-6 hours; After the reaction is completed, cool to 50°C, add an equal volume of deionized water, stir evenly, and then separate and remove the aqueous phase; The organic phase was dried over anhydrous sodium sulfate and distilled under reduced pressure to remove toluene to obtain the product.

9. The preparation method according to any one of claims 1 to 6, characterized in that The surfactant is a composite silane coupling agent, and the preparation process of the composite silane coupling agent includes the following steps: Add anhydrous ethanol and deionized water into the reaction vessel and stir to mix evenly at 25-30°C; Slowly add silane coupling agent and PFOTES in sequence while stirring and mix well; Raise the temperature to 50-60°C, control the pH of the solution system to 4-5, and continue stirring for 2 hours to form a composite silane network; Cool to room temperature, let stand for 30 min, and remove the aqueous phase by separation; The product is obtained by removing the residual ethanol by distillation under reduced pressure.

10. The preparation method according to any one of claims 1 to 6, characterized in that: The synergistic catalyst is a functionalized phosphine compound, and the preparation process of the functionalized phosphine compound includes the following steps: Add DMF solvent into the reaction vessel; Add triphenylphosphine at 50-60°C and stir until completely dissolved; Maintain the temperature, slowly add 2-chloromethylpyridine dropwise and stir evenly; Add thiobenzoic acid and continue stirring for 40 minutes, then raise the temperature to 70-80°C, add tetrabutylammonium bromide and stir evenly; Add sodium hydroxide solution dropwise to adjust the pH of the system to 7.0-7.5 and stir for 15 minutes; The mixture was cooled to 40°C and allowed to stand for 30 min. After solid-liquid separation, the DMF solvent was removed by vacuum distillation to collect the crude product. Recrystallize with ethanol 2 to 3 times the mass of the crude product and filter to obtain the recrystallized product; The recrystallized product was placed in a vacuum drying oven and dried at 50°C for 3-4 hours.

Images