Preparation method of dioctyltin oxide special catalyst for ultrafine electrophoretic coating
By using raw materials such as tetraoctyltin, tin tetrachloride, toluene and WO3/MgO, combined with pressurized spraying and multiple washing techniques, ultrafine, low chlorine, and low conductivity dioctyltin oxide was successfully prepared, solving the problems of large particle size and high chlorine content in the existing technology, and achieving efficient and economical preparation of electrophoretic coating catalysts.
Patent Information
- Application Number
- CN202510041497.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-10
- Publication Date
- 2025-04-08
AI Technical Summary
In the prior art, dioctyl tin oxide has a large particle size, high chlorine content and high conductivity, which cannot be used in electrophoretic coatings, and has high synthesis cost and complex routes, which limits its application scope.
Tetraoctyltin, tin tetrachloride, toluene and WO3/MgO are used as main raw materials, and ultrafine powder is formed by pressurized spraying device, and ultra-low conductivity pure water is washed multiple times to prepare ultra-fine, low chlorine, and low conductivity dioctyltin oxide.
The prepared dioctyl tin oxide has an ultrafine powder particle size D90 less than 10 μm, a conductivity less than 10 S/m, and a total chlorine content less than 50 PPM. It can replace imported products for the production of electrophoretic paint, improving the purity and performance of the product.
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Figure CN119775306A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of organic metals, and in particular relates to a method for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coatings. Background Art
[0002] Dioctyltin oxide is a widely used organic tin compound, usually in the form of white powder. Dioctyltin oxide is mainly used as an intermediate for the synthesis of PVC (polyvinyl chloride) organic tin series heat stabilizers. It is widely used in the fields of antioxidant catalysis, automotive coatings, tires, food and pharmaceutical packaging materials.
[0003] The existing organic tin catalyst for cathode electrophoretic coating is mainly based on traditional dibutyltin oxide. Dioctyltin oxide is used as a non-toxic catalyst to replace the toxic butyltin catalyst. Traditional dioctyltin oxide mainly reacts directly with sodium hydroxide in the form of dioctyltin chloride. Its product is difficult to grind due to its large particle size, high chlorine content and high conductivity, and cannot be used in electrophoretic coatings. It is only used as a PVC heat stabilizer. In addition, due to its high synthesis cost, complex route and unsatisfactory physical properties of the product, these factors limit its application range. In traditional preparation methods such as the direct iodine method, tin is easy to agglomerate during the catalytic reaction, resulting in low reaction efficiency, while producing by-products and impurity ions, making the inorganic ion content of the final product too high, the particle size is large and uneven, and has an adverse effect on downstream synthesis. Based on this, a preparation method for dioctyltin oxide, a special catalyst for ultrafine electrophoretic coatings, is developed to prepare ultrafine, low-chlorine, low-conductivity dioctyltin oxide, a special catalyst for electrophoretic coatings. Summary of the invention
[0004] In view of the deficiencies of the prior art, the present invention provides a method for preparing dioctyltin oxide, a catalyst specially used for ultrafine electrophoretic coatings. The dioctyltin oxide of the present invention uses tetraoctyltin, tin tetrachloride, toluene and a catalyst as main raw materials, does not use a traditional surfactant, forms ultrafine powder from the formed material through a special pressurized spray device, reduces product impurity inclusion, increases reactivity, and uses ultra-low conductivity pure water to wash the product multiple times to obtain ultrafine, low-chlorine, low-conductivity dioctyltin oxide specially used for cathode electrophoretic coating catalysts.
[0005] In order to achieve the above technical objectives, the technical solutions adopted by the present invention are as follows: The invention provides a method for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coatings. The dioctyltin oxide, a special catalyst for ultrafine electrophoretic coatings, is prepared from the following raw materials in parts by weight: 40-60 parts of dioctyltin chloride, 120-200 parts of toluene, and 0.5-3 parts of a catalyst; The preparation method specifically comprises the following steps: S1, adding dioctyltin chloride and toluene by weight into a mixing kettle and stirring uniformly to obtain an organic solution, dissolving the catalyst by weight in ethylenediamine, the amount ratio of the catalyst to ethylenediamine being 1 g:20-35 mL, to obtain a mixture A, adding the mixture A to the organic solution, introducing nitrogen protection, to obtain a mixture B; S2, pressurizing the mixture B through a booster pump, and then introducing it into the liquid alkali through a special spray head, controlling the temperature of the reactor to 60-80 ° C, and keeping the temperature for 2-4 hours to form an emulsion; S3, allowing the emulsion obtained in step S2 to stand, separating and removing the lower layer of alkaline water, adding ultrapure water for washing, and filtering to obtain a crude product of dioctyltin oxide; S4, drying the crude dioctyl tin oxide obtained in step S3 at 80°C to obtain dioctyl tin oxide, a catalyst specifically used for ultrafine electrophoretic coatings.
[0006] Furthermore, the special spray head is designed to atomize the mixture B uniformly and finely into tiny particles.
[0007] Furthermore, the liquid alkali is a sodium hydroxide solution with a mass fraction of 5%.
[0008] Further, the catalyst is WO3 / MgO; The raw materials for preparing WO3 / MgO are ammonium tungstate and magnesium hydroxide; The preparation method of WO3 / MgO specifically comprises the following steps: (1) Take ammonium tungstate and add distilled water to dissolve it, add magnesium hydroxide powder, stir for 30 min, mix evenly, and co-precipitate in a water bath at 80 °C. Stir at 80 °C for 6 h. After stirring, the solution is cooled to room temperature, filtered, washed, dried at 120 °C for 10 h, and ground to form powder; (2) The powder obtained in step (1) is placed in a muffle furnace for calcination, starting at room temperature, raising the temperature to 300 °C for calcination for 3 h, and then raising the temperature from 300 °C to 500 °C for further calcination to obtain WO3 / MgO.
[0009] Furthermore, the mass ratio of the ammonium tungstate to the magnesium hydroxide is 1:1.5-3, and the dosage ratio of the ammonium tungstate to distilled water is 1 g:60 mL.
[0010] Furthermore, the method for preparing ultrapure water is as follows: ordinary tap water is filtered through quartz sand and activated carbon, softened by exchange resin, and entered into a reverse osmosis membrane for treatment, the conductivity of the outlet water is less than 10 us / cm, and then the primary pure water is passed through an EDI device to obtain ultrapure water with a conductivity of less than 1 us / cm.
[0011] The raw materials for preparing the dioctyltin chloride are: tetraoctyltin, tin tetrachloride and high iodine value activated carbon; the preparation method of the dioctyltin chloride is: putting tetraoctyltin and tin tetrachloride into a reaction kettle, passing nitrogen protection, adding high iodine value activated carbon, heating to 150-180°C, keeping the temperature for reaction for 8 hours, and filtering the reactant to obtain the dioctyltin chloride.
[0012] Furthermore, the iodine value of the high iodine value activated carbon is 1400 mg / g.
[0013] Furthermore, the mass ratio of tetraoctyltin, tin tetrachloride and high iodine value activated carbon is 1:1-1.5:3-5.
[0014] The raw materials for preparing the tetraoctyltin are: a mixture of magnesium powder, n-octane chloride, tin tetrachloride and ether; The preparation method of tetraoctyltin specifically comprises the following steps: (a) Add a mixture of magnesium powder and ether in a ratio of 1 g:30 mL to a Grignard reactor, add n-octane chloride dropwise, raise the temperature to 90 °C until the Grignard reaction is initiated, continue to add n-octane chloride dropwise, the mass ratio of magnesium powder to n-octane chloride is 1:6-8, until the addition is completed, control the reaction temperature at 100-120 °C for 4 h, and cool to room temperature to form a mixed solution; (b) adding tin tetrachloride dropwise to the mixed solution obtained in step (a), wherein the volume ratio of tin tetrachloride to the mixed solution is 1:5, controlling the temperature of the reaction kettle at 50-100°C, and after the addition is completed, maintaining the temperature at 90-100°C, reacting for 2-4 hours, and obtaining a mixture C; (c) The mixture C obtained in step (b) is cooled to room temperature, and then washed with 5% dilute hydrochloric acid aqueous solution, the upper layer of the material is transferred to a dissolution drying kettle, the temperature is raised to 90-120° C., and the ether mixture in the material is removed by negative pressure distillation to obtain a crude tetraoctyltin product, and the crude tetraoctyltin product is distilled at 120° C. under extreme negative pressure to obtain a finished tetraoctyltin product.
[0015] Furthermore, the ether mixture is a mixture of diethyl ether and tetrahydrofuran, and the volume ratio of the two is 2:1.
[0016] Compared with the prior art, the present invention has the following beneficial effects: The ultrafine electrophoretic coating catalyst dioctyl tin oxide ultrafine powder prepared by the present invention has a particle size D90 less than 10 μm, a conductivity less than 10 S / m, and a total chlorine content less than 50 PPM, and can replace imported products for the production of electrophoretic paint. The present invention uses dioctyl tin chloride and toluene and adds a catalyst to react, does not use a traditional surfactant, and forms the formed material into an ultrafine powder through a special pressurized spray device, reduces impurity inclusion, and increases the reactivity. The product is washed multiple times with ultra-low conductivity pure water to obtain a catalyst-grade ultrafine, low-chlorine, low-conductivity ultrafine electrophoretic coating catalyst dioctyl tin oxide specifically used for cathode electrophoretic coating. WO3 / MgO is used as a catalyst in the preparation process. WO3 / MgO provides a suitable alkaline environment to promote the reaction of tetraoctyl tin and tetrachloride In the reaction between tin and tin, the alkaline sites provided by WO3 / MgO help to break and form chemical bonds. During the reaction, it helps to break the Sn-Cl bond in tin tetrachloride, allowing the chlorine atoms to combine with the tin atoms in tetraoctyltin to form dioctyltin chloride. In the process of converting dioctyltin chloride into dioctyltin oxide, the WO3 / MgO catalyst acts as an oxidant, promoting the removal of chlorine atoms and the formation of tin oxide. Moreover, the addition of WO3 / MgO helps to improve the stability and dispersibility of dioctyltin oxide and prevent it from aggregating or precipitating during the reaction. The WO3 / MgO catalyst has a higher catalytic efficiency than traditional sodium hydroxide, and can more quickly promote the reaction of tetraoctyltin and tin tetrachloride to form dioctyltin chloride, and further convert it into dioctyltin oxide. The active sites on the surface of the WO3 / MgO catalyst can interact with the molecules of tetraoctyltin and tin tetrachloride, promoting the dissociation of tin chloride and the formation of dioctyltin chloride. MgO provides an alkaline environment, which helps to neutralize the acidic substances produced in the reaction, thereby promoting the reaction to form dioctyltin oxide. WO3 is oxidizing and acts as an oxidant in the reaction, promoting the oxidation of organic tin compounds. The stability of the WO3 / MgO composite catalyst can prevent the catalyst from degrading during the reaction, and its dispersibility helps to improve the catalytic efficiency. In the process of preparing dioctyltin chloride, sodium hydroxide is not used, but high iodine value activated carbon is used. High iodine value activated carbon has more micropores and mesopores, providing a larger specific surface area, thereby enhancing its adsorption capacity for reactants and intermediates, helping to improve the conversion rate of reactants and the purity of products. The adsorption effect of activated carbon can remove certain components in the reaction, such as by-products or unreacted raw materials, thereby pushing the reaction equilibrium toward the direction of generating dioctyltin chloride. High iodine value activated carbon can selectively adsorb certain molecules, thereby improving the selectivity of target products and reducing the occurrence of side reactions. Activated carbon can be used as a carrier of catalysts, providing more active sites and increasing the dispersion of catalysts, thereby improving catalytic efficiency. Activated carbon has high thermal stability and can be used at higher reaction temperatures without decomposition.The raw materials used in the present invention can reduce pollution to the environment, are easier to separate and recover from the reaction mixture, and may realize the recycling of the catalyst. The solid catalyst may allow the reaction to be carried out under milder conditions, reducing energy consumption and equipment requirements. The solid catalyst is usually easier to separate and recover from the reaction mixture, and may realize the recycling of the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 This is a flow chart for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coatings of the present invention; Figure 2 This is a schematic diagram of the conductivity of dioctyltin oxide, a special catalyst for ultrafine electrophoretic coatings prepared in the present invention. DETAILED DESCRIPTION
[0018] In order to make the technical solution of the present invention better understood by the technical personnel in the field, and to make the above-mentioned features, purposes and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with the embodiments. The embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.
[0019] according to Figure 1 The preparation flow chart of the special catalyst dioctyltin oxide for ultrafine electrophoretic coating of the present invention is shown in the specific embodiment of the present invention as follows: Example 1: This example provides a method for preparing dioctyltin oxide, a catalyst for ultrafine electrophoretic coatings. The dioctyltin oxide, a catalyst for ultrafine electrophoretic coatings, is prepared from the following raw materials in parts by weight: 40 parts of dioctyltin chloride, 120 parts of toluene, and 0.5 parts of WO3 / MgO; The preparation method of the ultrafine electrophoretic coating special catalyst dioctyltin oxide specifically comprises the following steps: S1, 40 parts of dioctyltin chloride and 120 parts of toluene are put into a mixing kettle and stirred evenly to obtain an organic solution, 0.5 parts of WO3 / MgO are dissolved in ethylenediamine, the amount ratio of WO3 / MgO to ethylenediamine is 1 g:20 mL, to obtain a mixture A, the mixture A is added to the organic solution, nitrogen protection is introduced, to obtain a mixture B; S2, the mixture B obtained in step S1 is pressurized by a booster pump, and then introduced into a special spray head and sprayed into a 5% by mass sodium hydroxide solution, wherein the special spray head is designed to uniformly and finely atomize the mixture B into tiny particles, and the temperature of the reactor is controlled to be 60° C., and the reaction is kept warm for 2 h to form an emulsion; S3, the emulsion obtained in step S2 is allowed to stand, the lower layer of alkaline water is separated and removed, and then ultrapure water is added for washing 5 times, wherein the ultrapure water is obtained by filtering ordinary tap water through quartz sand and activated carbon, softening it through exchange resin, and entering a reverse osmosis membrane for treatment, and the effluent conductivity is 6 us / cm, thereby obtaining first-class pure water, and then the first-class pure water is passed through an EDI device to obtain ultrapure water with a conductivity of 0.2 us / cm, and the crude dioctyltin oxide is obtained by filtration; S4, drying the crude dioctyl tin oxide obtained in step S3 at 80° C. to obtain dioctyl tin oxide, a catalyst specifically used for ultrafine electrophoretic coatings.
[0020] The raw materials for preparing WO3 / MgO are ammonium tungstate and magnesium hydroxide; The preparation method of WO3 / MgO specifically comprises the following steps: (1) Take 2 parts of ammonium tungstate and add distilled water to dissolve, the dosage ratio of ammonium tungstate to distilled water is 1 g:60 mL, add magnesium hydroxide powder, the mass ratio of ammonium tungstate to magnesium hydroxide is 1:1.5, stir for 30 min, mix evenly, co-precipitate in 80 ℃ water bath, stir at 80 ℃ for 6 h, after stirring, cool the solution to room temperature, filter, wash, dry at 120 ℃ for 10 h, and grind to form powder after drying; (2) The powder obtained in step (1) is placed in a muffle furnace for calcination, starting at room temperature, raising the temperature to 300 °C for calcination for 3 h, then raising the temperature from 300 °C to 500 °C for further calcination, and cooling to room temperature to obtain WO3 / MgO.
[0021] The raw materials for preparing the dioctyltin chloride are: tetraoctyltin, tin tetrachloride and high iodine value activated carbon; the preparation method of the dioctyltin chloride is: 50 parts of tetraoctyltin and tin tetrachloride are put into a reaction kettle, nitrogen is introduced for protection, high iodine value activated carbon is added, the mass ratio of tetraoctyltin, tin tetrachloride and high iodine value activated carbon is 1:1:3, the temperature is raised to 150°C, the temperature is kept for reaction for 8 hours, and the reactant is filtered to obtain the dioctyltin chloride.
[0022] The raw materials for preparing the tetraoctyltin are: a mixture of magnesium powder, n-octane chloride, tin tetrachloride and ether; The preparation method of tetraoctyltin specifically comprises the following steps: (a) Add 60 parts of magnesium powder and a mixture of ether into a Grignard reactor. The mixture of ether is a mixture of ether and tetrahydrofuran in a volume ratio of 2:1. The amount ratio of the mixture of magnesium powder and ether is 1 g:30 mL. Add n-octane chloride dropwise. Raise the temperature to 90°C until the Grignard reaction is initiated. Continue to add n-octane chloride dropwise. The mass ratio of magnesium powder to n-octane chloride is 1:6 until the addition is completed. Control the reaction temperature at 100°C for 4 h. Cool to room temperature to form a mixed solution. (b) adding tin tetrachloride dropwise to the mixed solution obtained in step (a), wherein the volume ratio of tin tetrachloride to the mixed solution is 1:5, controlling the temperature of the reactor at 50°C, and maintaining the temperature at 90°C after the addition is completed, reacting for 2 hours, and obtaining a mixture C; (c) The mixture C obtained in step (b) is cooled to room temperature, and then washed with water by adding a 5% by mass dilute hydrochloric acid aqueous solution, the upper layer of the material is transferred to a dissolution drying kettle, the temperature is raised to 90° C., and the ether mixture in the material is removed by negative pressure distillation to obtain a crude tetraoctyltin product, and the crude tetraoctyltin product is distilled at 120° C. under extreme negative pressure to obtain a finished tetraoctyltin product.
[0023] Example 2: This example provides a method for preparing dioctyltin oxide, a catalyst for ultrafine electrophoretic coatings, wherein the dioctyltin oxide, a catalyst for ultrafine electrophoretic coatings, is prepared from the following raw materials in parts by weight: 50 parts of dioctyltin chloride, 160 parts of toluene, and 2 parts of WO3 / MgO; The preparation method of the ultrafine electrophoretic coating special catalyst dioctyltin oxide specifically comprises the following steps: S1, 50 parts of dioctyltin chloride and 160 parts of toluene are put into a mixing kettle and stirred evenly to obtain an organic solution, 2 parts of WO3 / MgO are dissolved in ethylenediamine, the amount ratio of WO3 / MgO to ethylenediamine is 1 g:26 mL, to obtain a mixture A, the mixture A is added to the organic solution, nitrogen protection is introduced, to obtain a mixture B; S2, the mixture B is pressurized by a booster pump, and then introduced into a special spray head and sprayed into a 5% by mass sodium hydroxide solution. The special spray head is designed to atomize the mixture B evenly and finely into tiny particles. The temperature of the reactor is controlled at 70 °C, and the reaction is kept warm for 3 hours to form an emulsion; S3, the emulsion obtained in step S2 is allowed to stand, the lower layer of alkaline water is separated and removed, and then ultrapure water is added for washing 5 times, wherein the ultrapure water is obtained by filtering ordinary tap water through quartz sand and activated carbon, softening it through exchange resin, and entering the reverse osmosis membrane for treatment, and the conductivity of the outlet water is 6 us / cm, and then the primary pure water is passed through an EDI device to obtain ultrapure water with a conductivity of 0.2 us / cm, and the crude dioctyltin oxide is obtained by filtration; S4, drying the crude dioctyl tin oxide obtained in step S3 at 80° C. to obtain dioctyl tin oxide, a catalyst specifically used for ultrafine electrophoretic coatings.
[0024] The raw materials for preparing WO3 / MgO are ammonium tungstate and magnesium hydroxide; The preparation method of WO3 / MgO specifically comprises the following steps: (1) Take 5 parts of ammonium tungstate and add distilled water to dissolve, the dosage ratio of ammonium tungstate to distilled water is 1 g:60 mL, add magnesium hydroxide powder, the mass ratio of ammonium tungstate to magnesium hydroxide is 1:2, stir for 30 min, mix evenly, co-precipitate in 80 ℃ water bath, stir at 80 ℃ for 6 h, after stirring, cool the solution to room temperature, filter, wash, dry at 120 ℃ for 10 h, and grind to form powder after drying; (2) The powder obtained in step (1) is placed in a muffle furnace for calcination, starting at room temperature, raising the temperature to 300 °C for calcination for 3 h, and then raising the temperature from 300 °C to 500 °C for further calcination to obtain WO3 / MgO.
[0025] The raw materials for preparing the dioctyltin chloride are: tetraoctyltin, tin tetrachloride and high iodine value activated carbon; the preparation method of the dioctyltin chloride is: 60 parts of tetraoctyltin and tin tetrachloride are put into a reaction kettle, nitrogen is introduced for protection, high iodine value activated carbon is added, the mass ratio of tetraoctyltin, tin tetrachloride and high iodine value activated carbon is 1:1.2:4, the temperature is raised to 160°C, the temperature is kept for reaction for 8 hours, and the reactant is filtered to obtain the dioctyltin chloride.
[0026] The raw materials for preparing the tetraoctyltin are: a mixture of magnesium powder, n-octane chloride, tin tetrachloride and ether; The preparation method of tetraoctyltin specifically comprises the following steps: (a) Add 80 parts of a mixture of magnesium powder and ether into a Grignard reactor, the amount ratio of the mixture of magnesium powder and ether is 1 g:30 mL, the mixture of ether is a mixture of ether and tetrahydrofuran, the volume ratio of the two is 2:1, add n-octane chloride dropwise, raise the temperature to 90 °C until the Grignard reaction is initiated, continue to add n-octane chloride dropwise, the mass ratio of magnesium powder to n-octane chloride is 1:6.5, until the addition is completed, control the reaction temperature at 110 °C for 4 h, and cool to room temperature to form a mixed solution; (b) adding tin tetrachloride dropwise to the mixed solution obtained in step (a), wherein the volume ratio of tin tetrachloride to the mixed solution is 1:5, and controlling the temperature of the reaction kettle at 80°C. After the addition is completed, maintaining the temperature at 95°C and reacting for 3 hours to obtain a mixture C; (c) The mixture C obtained in step (b) is cooled to room temperature, and then washed with 5% dilute hydrochloric acid aqueous solution, the upper layer of the material is transferred to a dissolution drying kettle, the temperature is raised to 90-120° C., and the ether mixture in the material is removed by negative pressure distillation to obtain a crude tetraoctyltin product, and the crude tetraoctyltin product is distilled at 120° C. under extreme negative pressure to obtain a finished tetraoctyltin product.
[0027] Example 3: This example provides a method for preparing dioctyltin oxide, a catalyst for ultrafine electrophoretic coatings. The dioctyltin oxide, a catalyst for ultrafine electrophoretic coatings, is prepared from the following raw materials in parts by weight: 60 parts of dioctyltin chloride, 200 parts of toluene, and 3 parts of WO3 / MgO; The preparation method of the ultrafine electrophoretic coating special catalyst dioctyltin oxide specifically comprises the following steps: S1, 60 parts of dioctyltin chloride and 200 parts of toluene are put into a mixing kettle and stirred evenly to obtain an organic solution, 3 parts of WO3 / MgO are dissolved in ethylenediamine, the amount ratio of WO3 / MgO to ethylenediamine is 1 g:35 mL, to obtain a mixture A, the mixture A is added to the organic solution, nitrogen protection is introduced, to obtain a mixture B; S2, the mixture B is pressurized by a booster pump, and then introduced into a special spray head and sprayed into a 5% by mass sodium hydroxide solution. The special spray head is designed to atomize the mixture B evenly and finely into tiny particles. The temperature of the reactor is controlled at 80 °C, and the reaction is kept warm for 4 hours to form an emulsion; S3, the emulsion obtained in step S2 is allowed to stand, the lower layer of alkaline water is separated and removed, and then ultrapure water is added for washing 5 times, wherein the ultrapure water is obtained by filtering ordinary tap water through quartz sand and activated carbon, softening it through exchange resin, and entering the reverse osmosis membrane for treatment, and the conductivity of the outlet water is 6 us / cm, and then the primary pure water is passed through an EDI device to obtain ultrapure water with a conductivity of 0.2 us / cm, and filtered to obtain crude dioctyltin oxide; S4, drying the crude dioctyl tin oxide obtained in step S3 at 80° C. to obtain dioctyl tin oxide, a catalyst specifically used for ultrafine electrophoretic coatings.
[0028] The raw materials for preparing WO3 / MgO are ammonium tungstate and magnesium hydroxide; The preparation method of WO3 / MgO specifically comprises the following steps: (1) Take 6 parts of ammonium tungstate and add distilled water to dissolve, the dosage ratio of ammonium tungstate to distilled water is 1 g:60 mL, add magnesium hydroxide powder, the mass ratio of ammonium tungstate to magnesium hydroxide is 1:3, stir for 30 min, mix evenly, co-precipitate in 80 ℃ water bath, stir at 80 ℃ for 6 h, after stirring, cool the solution to room temperature, filter, wash, dry at 120 ℃ for 10 h, and grind to form powder after drying; (2) The powder obtained in step (1) is placed in a muffle furnace for calcination, starting at room temperature, raising the temperature to 300 °C for calcination for 3 h, and then raising the temperature from 300 °C to 500 °C for further calcination to obtain WO3 / MgO.
[0029] The raw materials for preparing the dioctyltin chloride are: tetraoctyltin, tin tetrachloride and high iodine value activated carbon; the preparation method of the dioctyltin chloride is: 80 parts of tetraoctyltin and tin tetrachloride are put into a reaction kettle, nitrogen is introduced for protection, high iodine value activated carbon is added, the mass ratio of tetraoctyltin, tin tetrachloride and high iodine value activated carbon is 1:1.5:5, the temperature is raised to 180°C, the temperature is kept for reaction for 8 hours, and the reactant is filtered to obtain the dioctyltin chloride.
[0030] The raw materials for preparing the tetraoctyltin are: a mixture of magnesium powder, n-octane chloride, tin tetrachloride and ether; The preparation method of tetraoctyltin specifically comprises the following steps: (a) Add 90 parts of a mixture of magnesium powder and ether into a Grignard reactor, the amount ratio of the mixture of magnesium powder and ether is 1 g:30 mL, the mixture of ether is a mixture of ether and tetrahydrofuran, the volume ratio of the two is 2:1, add n-octane chloride dropwise, raise the temperature to 90 °C until the Grignard reaction is initiated, continue to add n-octane chloride dropwise, the mass ratio of magnesium powder and n-octane chloride is 1:8, until the addition is completed, control the reaction temperature at 120 °C for 4 h, and cool to room temperature to form a mixed solution; (b) adding tin tetrachloride dropwise to the mixed solution obtained in step (a), wherein the volume ratio of tin tetrachloride to the mixed solution is 1:5, and controlling the temperature of the reaction kettle at 100°C. After the addition is completed, maintaining the temperature at 100°C and reacting for 4 hours to obtain a mixture C; (c) The mixture C obtained in step (b) is cooled to room temperature, and then washed with 5% dilute hydrochloric acid aqueous solution, the upper layer of the material is transferred to a dissolution drying kettle, the temperature is raised to 120° C., and the ether mixture in the material is removed by negative pressure distillation to obtain a crude tetraoctyltin product, and the crude tetraoctyltin product is distilled at 120° C. under extreme negative pressure to obtain a finished tetraoctyltin product.
[0031] The difference between Comparative Example 1 and Example 1 is that the addition of catalyst WO3 / MgO is eliminated, and the rest is the same as Example 1.
[0032] The difference between Comparative Example 2 and Example 1 is that the preparation method of dioctyltin chloride is as follows: tetraoctyltin and tin tetrachloride are put into a reaction kettle, nitrogen is introduced for protection, a 10% by mass sodium hydroxide solution is added, the temperature is raised to 150°C, the reaction is kept warm for 8 hours, and the reactant is filtered to obtain dioctyltin chloride.
[0033] The difference between Comparative Example 3 and Example 1 is that the preparation method of dioctyltin oxide, a special catalyst for ultrafine electrophoretic coating, is as follows: weighing elemental tin, chlorooctane, tetrabutylammonium bromide and elemental iodine, the molar ratio of elemental tin, chlorooctane, tetrabutylammonium bromide and elemental iodine is 10:5:1.5:1, adding elemental tin, tetrabutylammonium bromide, elemental iodine and a first amount of chlorooctane into a reaction container, and starting heating and stirring; when the stirring condition temperature of the reaction system rises to a first temperature, the first temperature is 160°C, adding the remaining chlorooctane into the container; after adding the remaining chlorooctane, raising the reaction temperature to a second temperature, the second temperature is 180°C, and filtering the reaction liquid hot after reacting for 8 hours; after filtering the filtrate, cooling it to a third temperature, the third temperature is 80°C, and then adding sodium hydroxide solution and alcohol to the filtrate for hydrolysis, filtering the hydrolyzed solution, and obtaining dioctyltin oxide.
[0034] Experimental Example: Using the ultrafine electrophoretic coating catalyst dioctyl tin oxide prepared in Example 1-3 and Comparative Example 1-3 as a sample, the element content and yield in the prepared dioctyl tin oxide were tested. 50 mg of dioctyl tin oxide sample was weighed in each group, and heated in a water bath at 80 ° C with 5 mL of concentrated hydrochloric acid. When the white solid just turned into a colorless oil, the heating was stopped, methanol was added and transferred to a 250 mL volumetric flask and diluted to the scale to prepare a 0.2 g / L solution; tributyltin (98.6%) and tetrabutyltin (99.4%) were each dissolved in methanol to prepare a 1g / L solution, and the organic tin working solution was diluted with water before use. Buffer solution (1 mol / L acetic acid and 1 mol / L sodium acetate); sodium borohydride (purity of 99.7%) was prepared into a 4% aqueous solution, which was prepared on the spot.
[0035] Chromatographic conditions: The chromatographic column is a 2 m×3 mm hard glass column filled with 1.5% OV-101 / ChromosorbG (particle size 0.180-0.154 mm); injection port temperature: 220 ℃; column temperature: 235 ℃; detector temperature: 160 ℃. Carrier gas flow rate (high-purity nitrogen): 65 mL / min; auxiliary tail gas flow rate: 30 mL / min; hydrogen flow rate: 430 mL / min; air flow rate: 10 mL / min; purge gas: 55 mL / min.
[0036] Table 1
[0037] As can be seen from the data in Table 1, the present invention provides an effective method for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coatings. Through this preparation method, we have successfully achieved a significant reduction in the chlorine content, which is only 0.001%. This value is far lower than the limit of industry standards, indicating that the product we prepared has extremely high purity. At the same time, the tin content reaches 35.2%, which shows that our preparation method can effectively retain the active ingredients in dioctyltin oxide and ensure its application performance in electrophoretic coatings. Moreover, the D90 value is less than 10 μm, which shows that we have successfully prepared dioctyltin oxide powder with ultrafine particle size. The characteristics of this ultrafine powder enable it to have better dispersibility and higher catalytic efficiency in electrophoretic coatings, thereby improving the overall performance of the coating. In addition, the yield of dioctyltin oxide prepared by the method of the present invention is as high as 96.2%, which greatly improves production efficiency and economic benefits.
[0038] Figure 2 The conductivity of dioctyltin oxide, a special catalyst for ultrafine electrophoretic coatings prepared according to the preparation method of the present invention, is shown. It can be seen that the conductivity of Examples 1-3 of the present invention is significantly lower than that of Comparative Examples 1-3, and the conductivity of Examples 1-3 is lower than 10 S / m, indicating that dioctyltin oxide, a special catalyst for ultrafine electrophoretic coatings prepared by the present invention, helps to achieve a more uniform coating and improve coating efficiency.
[0039] In summary, the preparation method of dioctyltin oxide, a special catalyst for ultrafine electrophoretic coatings of the present invention, not only improves the purity and performance of the product, effectively reduces the chlorine content, increases the tin content, but also greatly improves the production efficiency and economic benefits. The increase in yield means that with the same raw material input, more product output can be obtained, which is of great significance for reducing production costs and improving market competitiveness, and provides an efficient and economical new choice for the electrophoretic coating industry.
[0040] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A method for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coatings, characterized in that: The ultrafine electrophoretic coating special catalyst dioctyl tin oxide is prepared from the following raw materials in parts by weight: 40-60 parts of dioctyl tin chloride, 120-200 parts of toluene, and 0.5-3 parts of catalyst; The preparation method of the ultrafine electrophoretic coating special catalyst dioctyltin oxide specifically comprises the following steps: S1, dioctyltin chloride and toluene are mixed by weight, stirred evenly to obtain an organic solution, the catalyst is dissolved by weight in ethylenediamine to obtain a mixture A, the mixture A is added to the organic solution, nitrogen is introduced for protection, and a mixture B is obtained; S2, subjecting the mixture B obtained in step S1 to pressure treatment, and then spraying it into liquid alkali to form an emulsion; S3, allowing the emulsion obtained in step S2 to stand, separating and removing the lower layer of alkaline water, adding ultrapure water for washing, and filtering to obtain a crude product of dioctyltin oxide; S4, drying the crude dioctyl tin oxide obtained in step S3 to obtain dioctyl tin oxide, a catalyst specifically used for ultrafine electrophoretic coatings.
2. The method for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coating according to claim 1, is characterized in that: In step S1, the ratio of the catalyst to ethylenediamine is 1 g:20-35 mL, and in step S2, the liquid alkali is a sodium hydroxide solution with a mass fraction of 5%.
3. The method for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coating according to claim 1, is characterized in that: In step S3, the method for preparing ultrapure water is as follows: ordinary tap water is filtered through quartz sand and activated carbon, softened by exchange resin, and treated by reverse osmosis membrane, and the conductivity of the outlet water is less than 10 us / cm to obtain primary pure water, and then the primary pure water is passed through an EDI device to obtain ultrapure water with a conductivity lower than 1 us / cm.
4. The method for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coating according to claim 1, is characterized in that: The catalyst is WO3 / MgO; The raw materials for preparing WO3 / MgO are ammonium tungstate and magnesium hydroxide; The preparation method of WO3 / MgO specifically comprises the following steps: (1) Take ammonium tungstate and add distilled water to dissolve it, add magnesium hydroxide, stir, mix evenly, co-precipitate under water bath conditions, then cool to room temperature, filter, wash, dry, grind, and form powder; (2) The powder obtained in step (1) is calcined and cooled to room temperature to obtain WO3 / MgO.
5. The method for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coating according to claim 4, is characterized in that: In step (1), the mass ratio of ammonium tungstate to magnesium hydroxide is 1:1.5-3, and the dosage ratio of ammonium tungstate to distilled water is 1 g:60 mL.
6. The method for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coating according to claim 1, is characterized in that: The raw materials for preparing the dioctyltin chloride are: tetraoctyltin, tin tetrachloride and high iodine value activated carbon; The preparation method of dioctyltin chloride is as follows: tetraoctyltin and tin tetrachloride are mixed, nitrogen is introduced for protection, high iodine value activated carbon is added, the temperature is raised to 150-180° C., and the mixture is reacted at this temperature to obtain a reactant, and the reactant is filtered to obtain dioctyltin chloride.
7. The method for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coating according to claim 6, is characterized in that: The mass ratio of the tetraoctyltin, tin tetrachloride and high iodine value activated carbon is 1:1-1.5:3-5.
8. The method for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coating according to claim 6, is characterized in that: The raw materials for preparing the tetraoctyltin are: a mixture of magnesium powder, tin tetrachloride, n-octane chloride and ether; The preparation method of tetraoctyltin specifically comprises the following steps: (a) Mix a mixture of magnesium powder and ether, add n-octane chloride dropwise, raise the temperature until the Grignard reaction is initiated, continue to add n-octane chloride dropwise until the addition is complete, control the reaction temperature to 100-120 °C, react for 4 h, and cool to room temperature to form a mixed solution; (b) adding tin tetrachloride dropwise to the mixed solution obtained in step (a), controlling the temperature to be 50-100°C, and after the addition is completed, maintaining the temperature to be 90-100°C, reacting for 2-4 hours, to obtain a mixture C; (c) The mixture C obtained in step (b) is cooled to room temperature, then washed with water, the upper layer of the material is dried, and the ether mixture in the material is removed by negative pressure distillation to obtain a crude tetraoctyltin product, and the crude tetraoctyltin product is distilled to obtain tetraoctyltin.
9. The method for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coating according to claim 8, characterized in that: The ether mixture is a mixture of diethyl ether and tetrahydrofuran, and the volume ratio of the two is 2:
1.
10. The method for preparing dioctyltin oxide, a special catalyst for ultrafine electrophoretic coating according to claim 8, characterized in that: In step (a), the amount ratio of the mixture of magnesium powder and ether is 1 g:30 mL; the mass ratio of the magnesium powder and n-octane chloride is 1:6-8. In step (b), the amount ratio of tin tetrachloride to the mixed solution is 1 g:40 mL.