Method for synthesizing granular dibutyltin oxide in one step

Abstract

The invention relates to a method for synthesizing granular dibutyltin oxide in one step, which comprises the following steps of: adding alkali liquor into a reactor, and heating to 60 DEG C while starting stirring; the preparation method comprises the following steps: dissolving dibutyltin dichloride in an organic solvent under a stirring state to obtain a dibutyltin dichloride solution; slowly dropwise adding a dibutyltin dichloride solution into the alkali liquor, and carrying out constant-temperature synthesis reaction for 3 hours at 60-70 DEG C; after the reaction is completed, centrifugally dewatering to obtain a synthetic reactant; adding a proper amount of alkali liquor and an organic solvent into the synthetic reactant again for secondary reaction, centrifugally separating a material containing water and a product to obtain a secondary reactant, washing the secondary reactant with water, centrifuging, and drying in vacuum to obtain the dibutyltin oxide with the chlorine content of less than or equal to 300ppm, the particle size of 25-100 meshes and uniform particle size. The granular dibutyltin oxide with uniform particle size can be synthesized in one step, the process is simple, the reaction conditions are easy to control, and the stability and reliability of the production process can be ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of deep processing of organic tin, and particularly relates to a method for controlling the particle size of dibutyltin oxide. Background Art

[0002] In the field of organotin deep processing technology, the continuous exploration of efficient and accurate synthesis methods has always been the focus of research. Dibutyltin oxide is an organotin with a wide range of applications, such as as a catalyst, thermal stabilizer, and intermediate. The traditional production process of dibutyltin oxide usually allows dibutyltin chloride to react with alkali, and then produces it by centrifugation and water washing. However, this production method has many disadvantages. On the one hand, a large amount of wastewater will be generated during the production process, which puts great pressure on the environment; on the other hand, the process flow is complicated, the reaction conditions are difficult to control, the production efficiency is low, and the resulting product has certain limitations in performance, and the product quality is unstable, which limits its application in high-end fields.

[0003] With the continuous advancement of science and technology and the growing demand for high-performance materials in various industries, the performance requirements for dibutyltin oxide are also getting higher and higher. Particle size control, as an important link in the performance optimization of dibutyltin oxide, has a vital impact on its application in different fields. Most dibutyltin oxide prepared by existing technologies is in the form of fine powder, which not only causes large dust in the product, but also is extremely inconvenient to use.

[0004] As a new type of coating with excellent performance, electrophoretic coating is widely used in the coating field of automobiles, metal workpieces, electromechanical and other hardware due to its smooth coating film, good water resistance and chemical resistance. This process has high requirements for the purity, particle size, chlorine content / conductivity and other indicators of dibutyltin oxide. At present, conventional dibutyltin oxide products on the market generally have problems such as uneven particle size, high chlorine residue and high conductivity. In the application of the coating industry, these shortcomings are likely to lead to poor catalytic effect, resulting in obvious defects in the coating, and thus cannot meet its use requirements in electrophoretic coatings. Summary of the invention

[0005] The purpose of the present invention is to solve the deficiencies of the prior art and to provide a one-step method for synthesizing granular dibutyltin oxide with a simple process flow, easy-to-control reaction conditions, simple production equipment, high production efficiency, high yield and stable and reliable product quality.

[0006] The technical solution adopted by the present invention is as follows: A one-step method for synthesizing granular dibutyltin oxide is as follows: (1) Add alkali solution to the reactor and heat it to 60°C while stirring; the alkali solution is a mixed solution of sodium hydroxide and ammonia water, or a mixed solution of potassium hydroxide and ammonia water, and the mass concentration of the alkali solution is 5% to 20%; the mass ratio of sodium hydroxide to ammonia water is 100:5-6; the mass ratio of potassium hydroxide to ammonia water is 100:4-5. Different alkali solution combinations and concentrations will have different effects on the reaction rate, the particle size and purity of the product. The ratio of the mixed solution of sodium hydroxide and ammonia water and the mixed solution of potassium hydroxide and ammonia water must be strictly controlled to effectively promote the reaction and make the particle size of the product more uniform. Otherwise, the reaction will be unbalanced, resulting in uneven particles, reduced conversion rate and poor product stability. Therefore, in practical applications, it is necessary to select a suitable alkali solution according to specific needs and conditions. At the same time, the reaction process and product performance can be optimized by adjusting the concentration of the alkali solution. A higher alkali concentration may speed up the reaction, but may also lead to an increase in side reactions; a lower alkali concentration may slow down the reaction, but the purity of the product may be higher; (2) Dissolve dibutyltin dichloride in an organic solvent under stirring to obtain a dibutyltin dichloride solution; the mass ratio of dibutyltin dichloride to the organic solvent is 100: 1 to 3, then slowly add the dibutyltin dichloride solution to the alkali solution at a dropping speed of 30 drops / minute to carry out a constant temperature synthesis reaction, the reaction temperature is 60-70°C, and the constant temperature reaction time is 3 hours; after the reaction is completed, centrifugal dehydration is carried out to obtain a synthetic reactant; the amount of dibutyltin dichloride solution added is 30% to 70% of the mass of the alkali solution; the organic solvent is one of pentane, hexane, octane, cyclohexane, cyclohexanone, toluene cyclohexanone, chlorobenzene, dichlorobenzene, methanol, ethanol, isopropanol, toluene, xylene, ethyl ether, butyl ether, acetone, methyl butyl ketone, methyl isobutyl ketone, phenol, and ethylene glycol monoethyl ether. The dropping speed and reaction temperature need to be strictly controlled, as these two key factors directly affect the progress of the reaction and the quality of the product. Too fast a droplet acceleration may cause the reaction to run away and produce by-products; too high or too low a temperature may affect the reaction rate and the particle size distribution of the product. Organic solvents can not only dissolve dibutyltin dichloride, but also promote the reaction and the separation of the product. The dosage ratio of organic solvents also needs to be precisely controlled according to the requirements of the reaction. Excessive dosage will lead to increased costs and environmental pollution; too little dosage will affect the reaction and the quality of the product. (3) Adding an appropriate amount of sodium hydroxide or potassium hydroxide and the same organic solvent as in step (2) to the synthetic reactants again to carry out a secondary reaction; the amount of alkali solution added is 200% to 300% of the mass of the synthetic reactants, and the amount of organic solvent added is 2% to 5% of the mass of the synthetic reactants; the secondary reaction temperature is 60 to 70°C, and the constant temperature reaction time is 2 hours; (4) After the secondary reaction is completed, the organic solvent is recovered and the reactants are centrifuged and dehydrated to obtain the secondary reactants. The recovered organic solvent can be recycled after proper treatment and purification, which not only reduces production costs but also reduces environmental pollution; (5) The secondary reactants are sequentially washed with water to remove impurities and unreacted substances, and then centrifuged to further separate the products. Finally, the water in the products is removed under vacuum drying conditions to obtain dibutyltin oxide with a chlorine content of ≤300ppm and a particle size of 25 to 100 meshes and uniform particle size.

[0007] The present invention has the following significant advantages: The present invention uses dibutyltin dichloride and alkali solution of a specific concentration as core raw materials, and performs a synthesis reaction in a heterogeneous system composed of an organic solvent and an aqueous solution. Through the precise construction of the reaction system, the raw materials can fully interact with each other under a specific environment, laying a foundation for synthesizing high-quality dibutyltin oxide. After the synthesis reaction is completed, an appropriate amount of alkali solution is added to carry out a secondary reaction, which can further optimize the performance and purity of the product and effectively regulate the particle size of the dibutyltin oxide.

[0008] The method of the present invention can make dibutyltin oxide sticky after using a certain solvent, and solidify into hollow small particles during the reaction, and make the product particles present a complete and uniform state. Such uniform granular products not only reduce dust problems, but also are more convenient in use and storage.

[0009] In addition, since the organic tin and the aqueous phase are immiscible after the reaction, the traditional method requires a large number of washing and desalting times for solid dibutyltin oxide, which not only consumes a large amount of water resources, but also increases production costs. However, after using a certain solvent, the method of the present invention will precipitate the dibutyltin dichloride contained in the dibutyltin oxide while reacting to generate dibutyltin oxide. This process not only increases the reaction conversion rate, reduces the chlorine content, but also improves the purity of the product. In addition, since this product is a granular dibutyltin oxide, the contact area increases during washing, the washing effect is significantly improved, and the wastewater discharge can be greatly reduced, which is more in line with environmental protection requirements.

[0010] (2) The method of the present invention uses a mixed solution of sodium hydroxide and ammonia water or a mixed solution of potassium hydroxide and ammonia water as the alkali solution, and strictly controls the mass ratio of sodium hydroxide to ammonia water, the mass ratio of potassium hydroxide to ammonia water, and the mass concentration of the alkali solution. Because ammonia water reacts with sodium hydroxide and potassium hydroxide, not only the alkali solution is made softer, but also it is ensured that only sodium chloride or potassium chloride is generated during the reaction process, and no ammonium salt or mixed salt is generated, thereby preventing the by-product from having complex components.

[0011] (3) The dibutyltin oxide product produced by the method of the present invention has stable and reliable quality, and the key indicators of the product are excellent. Its chlorine content is ≤300ppm, and the tin direct recovery rate is greater than 98.0%, and can reach up to 99.0% or more. The product particle size is between 25 and 100 meshes, and the particle size can be precisely controlled according to the specific requirements of customers to meet the personalized needs of different customers.

[0012] (4) The method of the present invention has safe process, simple equipment, easy-to-control conditions, high production efficiency, high yield and low production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a process flow chart of the present invention; Figure 2 Schematic diagram of the equipment system used in the embodiment of the present invention. DETAILED DESCRIPTION

[0014] The present invention is further described in detail below through specific implementation cases. The process flow of the method of the present invention is shown in Figure 1, which clearly shows the specific operations of each step and the flow of materials. Those skilled in the art should understand that these implementation cases are only a specific description of the present invention, rather than a limitation of the scope of protection of the present invention. Example 1

[0015] A one-step method for synthesizing granular dibutyltin oxide. Pump 4150kg of 10% sodium hydroxide solution from an alkali solution metering tank into a No. 1 reactor, start stirring, and add 100kg of 20% ammonia water at the same time, keeping the temperature at 60°C. Add 1500kg of commercially available or self-produced yellow crystalline dibutyltin dichloride to a No. 2 reactor, add 15kg of pentane to the dibutyltin dichloride, start stirring and keep the temperature at 70°C, stop stirring for 30 minutes, and obtain a dibutyltin dichloride solution. Then slowly drop the dibutyltin dichloride solution in the No. 2 reactor into the No. 1 reactor to react with the alkali solution, control the drop rate to 30 drops per minute, keep the No. 1 reactor in a stirring state during the drop addition, and keep the temperature at 70°C for 3h. After the synthesis reaction is completed, take out the reactant and centrifuge and dehydrate to obtain a solid synthetic reactant. Discharge the separated reaction brine into the sewage system for treatment. At the same time, prepare 2000kg of sodium hydroxide solution with a mass concentration of 2% and pump it into the 2# reactor. At the same time, add 15kg of pentane, start stirring and keep 60℃, let the synthetic reactants after centrifugation fall into the 2# reactor, and react with the mixed solution of alkali solution and pentane for secondary reaction, keep 70℃ constant temperature reaction for 2h, and open the vacuum valve of the 2# reactor, keep the vacuum degree greater than -0.07Mpa, distill the solvent until the distillation condenser tube of the condenser connected to the reactor has no temperature, stop stirring, take out the reactants and centrifuge them to obtain granular secondary reactants, namely dibutyltin oxide. Add 3000kg of pure water to the 1# reactor, pour the granular dibutyltin oxide after centrifugation into the 1# reactor, keep 60℃ water washing for 30 minutes, and sample and test the chlorine content of the product after 3 cycles of water washing. If it is less than 200ppm, the water washing can be stopped, otherwise it can be washed 1~2 times. The washing water can be recycled. After washing, centrifugal drying was performed to obtain uniformly granulated dibutyltin oxide product 1215k, with a tin content of 47.58%, a total chlorine content of 216 ppm, a tin direct recovery rate of 98.65%, a particle size ranging from 20 mesh to 50 mesh, and a very small amount of powder. Example 2

[0016] A one-step method for synthesizing granular dibutyltin oxide. 4150kg of sodium hydroxide solution with a mass fraction of 10% is pumped from an alkali solution metering tank into a No. 1 reactor, stirring is started, and 80kg of 20% ammonia water is added at the same time, and the temperature is maintained at 60°C. 1500kg of dibutyltin dichloride is added to a No. 2 reactor, and then 40kg of an organic solvent cyclohexanone is added and stirring is started, and the temperature is maintained at 70°C for 30 minutes to obtain a dibutyltin dichloride solution. Then the dibutyltin dichloride solution is slowly added dropwise to the No. 1 reactor to react with the alkali solution, and the stirring is stopped after the reaction is maintained at 70°C for 3 hours, and the reactant is taken out and centrifuged for dehydration to obtain a solid synthetic reactant. The separated reaction brine is discharged into the sewage system. At the same time, prepare 2000kg of sodium hydroxide solution with a mass concentration of 2% and pump it into the 2# reactor. At the same time, add 40kg of organic solvent cyclohexanone, start stirring and keep it at 60℃. The synthetic reactants after centrifugation fall into the 2# reactor for secondary reaction with the mixed solution of alkali solution and cyclohexanone, keep the constant temperature at 70℃ for 2h, then open the vacuum valve of the 2# reactor, keep the vacuum degree greater than -0.07Mpa to distill the solvent, stop stirring after the distillation condenser has no temperature, take out the reactants and centrifuge and dehydrate them to obtain a solid secondary reactant, namely dibutyltin oxide. Add 3000kg of pure water to the 1# reactor, pour the secondary reactant dibutyltin oxide after centrifugation into the 1# reactor, keep it at 60℃ for water washing for 30 minutes, and then sample and test the chlorine content of dibutyltin oxide after 3 cycles of water washing. If it is less than 200ppm, the water washing can be stopped, otherwise it can be washed 1~2 times until the chlorine content meets the requirements. The washing water can be recycled. After washing, centrifugal drying was performed to obtain a uniformly granular dibutyltin oxide product 1210k, with a tin content of 47.49%, a total chlorine content of 187 ppm, a tin direct recovery rate of 98.05%, a particle size of more than 70 mesh, and a trace amount of powder. Example 3

[0017] A one-step method for synthesizing granular dibutyltin oxide. 4150kg of 10% sodium hydroxide solution is pumped from an alkali solution metering tank into a No. 1 reactor, stirring is started, and 150kg of 20% ammonia water is added at the same time, and the temperature is maintained at 60°C. 1500kg of dibutyltin dichloride is added to a No. 2 reactor, and then 15kg of an organic solvent chlorobenzene is added and stirring is started, and the temperature is maintained at 65°C for 30 minutes to obtain a dibutyltin dichloride solution. Then the dibutyltin dichloride solution is slowly added dropwise to the No. 1 reactor to react with the alkali solution, and the stirring is stopped after the reaction is maintained at 65°C for 3 hours, and the reactant is taken out and centrifuged for dehydration to obtain a solid synthetic reactant. The separated reaction brine is discharged into the sewage system. At the same time, prepare 2000kg of sodium hydroxide solution with a mass concentration of 1.5% and pump it into the 2# reactor. At the same time, add 30kg of chlorobenzene, start stirring and keep 65℃. The synthetic reactants after centrifugation fall into the 2# reactor for secondary reaction with the mixed solution of alkali solution and cyclohexanone, keep 65℃ constant temperature reaction for 2h, then open the vacuum valve of the 2# reactor, keep the vacuum degree greater than -0.07Mpa to distill the solvent, stop stirring after the distillation condenser has no temperature, take out the reactants and centrifuge and dehydrate them to obtain a solid secondary reactant, namely dibutyltin oxide. Add 3000kg of pure water to the 1# reactor, pour the secondary reactant dibutyltin oxide after centrifugation into the 1# reactor, keep 60℃ for water washing for 30 minutes, and then cycle water washing for 3 times, take samples and test the chlorine content of dibutyltin oxide, and stop water washing if it is less than 200ppm, otherwise, wash it 1~2 times until the chlorine content meets the requirements. After washing, centrifugal drying was performed to obtain a uniform particle dibutyltin oxide product 1220k, with a tin content of 47.51%, a total chlorine content of 184 ppm, a tin direct recovery rate of 98.01%, a uniform particle size greater than 70 mesh, and a trace amount of powder. Example 4

[0018] A one-step method for synthesizing granular dibutyltin oxide. 5820kg of 10% potassium hydroxide aqueous solution is pumped from an alkali solution metering tank into a No. 1 reactor, stirring is started, and 150kg of 20% ammonia water is added at the same time, and the temperature is maintained at 60°C. 1500kg of dibutyltin dichloride is added to a No. 2 reactor, and 20kg of an organic solvent ethylene glycol monoethyl ether is added and stirring is started, and the temperature is maintained at 70°C. Stirring is stopped after 30 minutes to obtain a dibutyltin dichloride solution. Then, the dibutyltin dichloride solution is slowly added dropwise to the No. 1 reactor to react with the alkali solution, and the stirring of the No. 1 reactor is stopped after the reaction is maintained at 70°C for 3 hours, and the reactant is taken out and centrifuged for dehydration to obtain a synthetic reactant. At the same time, prepare a potassium hydroxide solution with a mass concentration of 2%, a total of 2800kg, pump it into the 2# reactor, add 20kg of organic solvent ethylene glycol monoethyl ether, start stirring and maintain 60℃, drop the centrifuged synthetic reactant, i.e. dibutyltin oxide, into the 2# reactor for secondary reaction, maintain constant temperature reaction at 70℃ for 2h, open the vacuum valve of the 2# reactor and maintain the vacuum degree greater than -0.07Mpa, distill the solvent until there is no temperature in the distillation condenser, stop stirring, take out the reactant and centrifuge it to obtain a solid secondary reactant, i.e. dibutyltin oxide. Add 3000kg of pure water to the 1# reactor, pour the dibutyltin oxide obtained by centrifugation into the 1# reactor, maintain 60℃ for 30 minutes, and sample and test the chlorine content of the product after 3 cycles of water washing. If it is lower than 200ppm, the water washing can be stopped, otherwise 1~2 more water washings can be performed until the chlorine content meets the requirements. After washing, centrifugal drying was performed to obtain a uniformly granulated dibutyltin oxide product 1208k, with a tin content of 47.67%, a total chlorine content of 267 ppm, a tin direct recovery rate of 98.26%, a particle size between 50 mesh and 70 mesh, and a very small amount of powder. Example 5

[0019] A one-step method for synthesizing granular dibutyltin oxide. 5820kg of 10% potassium hydroxide aqueous solution is pumped from an alkali solution metering tank into a No. 1 reactor, stirring is started, and 200kg of 20% ammonia water is added at the same time, and the temperature is maintained at 60°C. 1500kg of dibutyltin dichloride is added to a No. 2 reactor, and 25kg of an organic solvent, isopropanol, is stirred, maintained at 60°C, and stirring is stopped after 30 minutes to obtain a dibutyltin dichloride solution. Then, the dibutyltin dichloride solution is slowly added dropwise to the No. 1 reactor to react with the alkali solution, and the No. 1 reactor is stopped after the reaction is maintained at a constant temperature of 60°C for 3 hours, and the reactant is taken out and centrifuged for dehydration to obtain a synthetic reactant. At the same time, prepare a potassium hydroxide solution with a mass concentration of 1% and pump it into the 2# reactor. At the same time, add 20kg of isopropanol, start stirring and keep it at 60℃, and drop the centrifuged synthetic reactant, i.e. dibutyltin oxide, into the 2# reactor for secondary reaction. After keeping the constant temperature at 60℃ for 2h, open the vacuum valve of the 2# reactor and keep the vacuum degree greater than -0.07Mpa, distill the solvent until there is no temperature in the distillation condenser, stop stirring, take out the reactant and centrifuge it to obtain a solid secondary reactant, i.e. dibutyltin oxide. Add 3000kg of pure water to the 1# reactor, pour the dibutyltin oxide obtained by centrifugation into the 1# reactor, keep it at 60℃ for 30 minutes, and sample and test the chlorine content of the product after 3 cycles of water washing. If it is less than 200ppm, the water washing can be stopped. After washing, centrifugal drying was performed to obtain uniformly granulated dibutyltin oxide product 1210k, with a tin content of 46.97%, a total chlorine content of 269 ppm, a tin direct recovery rate of 98.02%, a particle size between 50 mesh and 70 mesh, and a very small amount of powder.

[0020] The above embodiments are only typical embodiments of the present invention. According to the content of the claims, the organic solvent is not limited to the several types described in the embodiments, and can also be hexane, octane, cyclohexane, cyclohexanone, dichlorobenzene, methanol, ethanol, isopropanol, toluene, xylene, ether, butyl ether, acetone, methyl butyl ketone, methyl isobutyl ketone, phenol.

[0021] The reactor, condenser, etc. used in the present invention are prior art equipment, and the connection method between the condenser and the reactor is also a conventional connection method in the technical field. The reactor is equipped with a steam heating jacket or an electric heating jacket to heat the material in the reactor, and a stirring device is installed in the reactor to stir the material. The reactor can be connected to a vacuum valve to evacuate the reactor. Figure 2 The equipment system used in the embodiment of the present invention is schematically drawn, wherein 1 is a 1# reactor with a stirring mechanism, 2 is a 2# reactor with a stirring mechanism, 3 is a condenser, and the 2# reactor is equipped with a vacuum valve 4. The condenser is connected to the 2# reactor through a pipeline. Both reactors have a feeding port and a discharging port, and each works independently.

[0022] Unless otherwise specified, all percentages described in the present invention are by mass percentages.

Claims

1. A one-step method for synthesizing granular dibutyltin oxide, characterized in that: Here’s how: (1) adding alkali solution to the reactor and heating it to 60° C. while stirring; the alkali solution is a mixed solution of sodium hydroxide and ammonia water, or a mixed solution of potassium hydroxide and ammonia water, and the mass concentration of the alkali solution is 5% to 20%; the mass ratio of sodium hydroxide to ammonia water is 100:5-6; the mass ratio of potassium hydroxide to ammonia water is 100:4-5; (2) dissolving dibutyltin dichloride in an organic solvent under stirring to obtain a dibutyltin dichloride solution; the mass ratio of dibutyltin dichloride to the organic solvent is 100: 1 to 3, then slowly dropping the dibutyltin dichloride solution into the alkali solution at a dropping speed of 30 drops / minute to carry out a constant temperature synthesis reaction, the reaction temperature is 60-70°C, and the constant temperature reaction time is 3 hours; after the reaction is completed, centrifugal dehydration is carried out to obtain a synthetic reactant; the amount of the dibutyltin dichloride solution added is 30% to 70% of the mass of the alkali solution; the organic solvent is one of pentane, hexane, octane, cyclohexane, cyclohexanone, toluene cyclohexanone, chlorobenzene, dichlorobenzene, methanol, ethanol, isopropanol, toluene, xylene, ether, butyl ether, acetone, methyl butyl ketone, methyl isobutyl ketone, phenol, and ethylene glycol monoethyl ether; (3) Adding an appropriate amount of sodium hydroxide or potassium hydroxide and the same organic solvent as in step (2) to the synthetic reactants again for a secondary reaction; the amount of alkali solution added is 200% to 300% of the mass of the synthetic reactants, and the amount of organic solvent added is 2% to 5% of the mass of the synthetic reactants; the secondary reaction temperature is 60 to 70°C, and the constant temperature reaction time is 2 hours; (4) After the secondary reaction is completed, the organic solvent is recovered and the reactants are centrifuged and dehydrated to obtain secondary reactants; (5) The secondary reactant is washed with water, centrifuged and vacuum dried to obtain dibutyltin oxide having a chlorine content of ≤300 ppm and a particle size of 25 to 100 meshes and uniform particle size.

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