Preparation method of low-chlorine low-conductivity dimethyl tin oxide

Abstract

The invention relates to a preparation method of low-chlorine low-conductivity dimethyl tin oxide, which comprises the following steps: firstly, carrying out synthetic reaction on a dimethyl tin dichloride aqueous solution and alkali liquor to prepare a dimethyl tin oxide crude product; adding toluene to extract a crude product, standing for phase splitting, separating out lower-layer saline water, adding deionized water into the kettle, starting stirring, heating, pumping negative pressure, distilling to remove toluene, and carrying out filter pressing on the material to obtain a dimethyltin oxide material; washing the dimethyl tin oxide material with deionized water, adding a small amount of industrial alcohol at the same time to remove residual chloride ions and alkali metal ions, carrying out filter pressing after washing is completed, and carrying out secondary washing and filter pressing; and finally, drying and crushing a wet material obtained by filter pressing to prepare a low-chlorine low-conductivity dimethyl tin oxide product with the chlorine content of less than 0.1% and the conductivity of less than 50 [mu] S / cm. The method disclosed by the invention is simple to operate and easy to control, the prepared dimethyl tin oxide product can meet the use requirements of customers on low chlorine and low conductivity, and the product quality is stable.

Description

Technical Field

[0001] The invention belongs to the technical field of deep processing of organic tin products, and specifically relates to a preparation method of low-chlorine and low-conductivity dimethyl tin oxide. Background Art

[0002] Dimethyl tin oxide is a white powdery solid and an organic chemical raw material. It is mainly used in the production of methyl-type PVC heat stabilizers, such as carboxylic acid-type methyl tin and mercaptan-type methyl tin. It can also be used as a catalyst in the production of polyester resins for powder coatings and as a catalyst in the production of some antioxidant products.

[0003] Chinese patent CN200910099743.8 discloses a method for preparing methyltin oxide, which comprises adding methyltin chloride into a reactor, adding water and stirring until completely dissolved, heating to 50-60°C, then slowly and evenly adding an alkali metal hydroxide aqueous solution or ammonia water, the reaction temperature is 30-110°C, the reaction time is 2-5 hours, the reaction end point is controlled at a pH value of 7-9, and finally the reaction solution is filtered, washed and purified to obtain solid methyltin oxide. Patent CN200910101033.4 also discloses a method for preparing methyl tin oxide, wherein metallic tin, methyl chloride and tin tetrachloride are first subjected to alkyl halogenation reaction at a temperature of 130-150°C and a pressure of 0.2-0.5MPa to obtain a first mixed intermediate; then the first mixed intermediate is pressed into a distillation kettle, and tin tetrachloride is added to react to obtain a second mixed intermediate; then the second mixed intermediate is subjected to vacuum distillation and purification, and absorbed with water to obtain a third mixed intermediate aqueous solution; finally, the third mixed intermediate aqueous solution and ammonia water are semi-continuously added to the reactor, the pH value of the reaction solution is maintained at 8.0-8.5, and after reacting for 2 hours, tap water is added for washing, and the mixture is subjected to vacuum distillation and dehydration to obtain methyl tin oxide. The chlorine content of methyl tin oxide obtained by the above two preparation methods is about 0.5%, and the conductivity is greater than 400μS / cm, which cannot meet the use requirements of downstream coating customers for low chlorine and low conductivity. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a method for preparing low-chloride and low-conductivity dimethyl tin oxide.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A method for preparing low-chlorine and low-conductivity dimethyl tin oxide, the method steps are as follows: (1) First, carry out the synthesis reaction: put the dimethyltin dichloride aqueous solution into the reactor, start stirring, then slowly and evenly add the alkali solution to react, control the reaction temperature at 20-50°C, and the reaction end point is when the pH value reaches 8.0-10.0, and then keep the temperature to react for 1-3 hours; (2) Extraction of crude product: Add a certain amount of solvent toluene into the reactor, and heat the reactor to 60-80°C, continue to keep the temperature for 1-2 hours, and then let it stand for phase separation; after the lower aqueous phase is separated, the upper layer is a white paste formed by the miscibility of dimethyl tin oxide and solvent toluene. The purpose of this step is to fully distribute the dimethyl tin oxide material generated by the reaction in toluene and separate it from the brine, thereby reducing the conductive ions in the crude product. Although dimethyl tin oxide cannot be dissolved in toluene, it can form a paste-like form with toluene, playing a similar role to extraction; (3) Solvent removal: Add a certain amount of deionized water into the reactor, start stirring, and then distill toluene at a temperature of 50-90°C and a vacuum degree of -0.050-0.070 MPa. After the toluene is completely removed, filter the material to obtain dimethyl tin oxide material; (4) Adequate water washing: Add a certain amount of deionized water to the water washing kettle, start stirring, and then put the filtered dimethyl tin oxide material into the water washing kettle for water washing. At the same time, add a small amount of industrial alcohol to fully disperse the dimethyl tin oxide material in the water, improve the water washing effect, and then better remove the residual chloride ions and alkali metal ions. After water washing, the material is filtered. While filtering, add a certain amount of deionized water to the water washing kettle again, start stirring, and then return the material to the water washing kettle for a second water washing. After the second water washing, the material is filtered again; (5) Drying and crushing: The filtered material is dried at 70-110°C until the moisture content reaches the required level, and then the material is crushed to obtain a low-chlorine and low-conductivity dimethyl tin oxide product with a chlorine content of less than 0.1% and a conductivity of less than 50 μS / cm.

[0006] Furthermore, the alkali solution used in step (1) is sodium hydroxide solution or ammonia water.

[0007] Furthermore, the amount of toluene used in step (2) is 50% to 100% of the mass of the dimethyltin dichloride aqueous solution.

[0008] Furthermore, the toluene distilled in step (3) is recovered by condensation and then recycled.

[0009] Furthermore, the amount of industrial alcohol used in step (4) is 1% by mass of the dimethyltin dichloride aqueous solution.

[0010] The method of the present invention is simple to operate and easy to control. The obtained dimethyl tin oxide product has low chlorine content and conductivity, with the chlorine content being less than 0.1% and the conductivity being less than 50 μS / cm, and can meet the use requirements of customers for low chlorine and low conductivity. The product quality is stable. In addition, the solvent toluene can be recovered and repeatedly recycled, saving raw materials and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The figure is a process flow chart for the preparation of low-chloride and low-conductivity dimethyl tin oxide. DETAILED DESCRIPTION

[0012] The present invention is further described below in conjunction with the examples, which are only preferred embodiments of the method of the present invention and are not intended to limit the scope of protection of the present invention. Example 1

[0013] A method for preparing low-chlorine and low-conductivity dimethyl tin oxide, such as Figure 1 As shown, 1000 kg of dimethyltin dichloride aqueous solution with a tin content of 25.89% and a chlorine content of 15.61% is put into a reactor with a steam jacket, stirring is started, and then alkaline liquid ammonia water is slowly and evenly added to carry out a synthetic reaction to obtain a crude dimethyltin oxide product, and the reaction temperature is controlled at 30-35°C to a pH value of 9.0 at the end, and then the reaction is kept warm for 3 hours. After the reaction is completed, 1000 kg of toluene solvent is added to the reactor to extract the crude dimethyltin oxide, and the reactor is heated to 80°C, and the reaction is continued for 1.5 hours, and then the phases are separated. After separating the lower aqueous phase, the upper layer of dimethyltin oxide is left as a white paste (organic phase) distributed in toluene. The aqueous phase is sent to a sewage treatment plant for treatment. Then, 1500kg of deionized water was added to the reactor, stirring was started, and the vacuum pump was turned on to draw negative pressure to the reactor, so that the vacuum degree in the reactor reached -0.060MPa. At the same time, steam was passed through the steam jacket of the reactor, and the temperature in the reactor was raised to 70°C to distill the toluene solvent. After the toluene was completely removed, the material was filtered to obtain dimethyl tin oxide material (filter cake). The water phase filtered out was sent to the sewage treatment plant for treatment. The distilled toluene was collected by condensation and put into the next batch for use. After that, 1500kg of deionized water was added to the washing kettle, stirring was started, and the filtered dimethyl tin oxide material was put into the washing kettle for washing. At the same time, 10kg of industrial alcohol was added to make the dimethyl tin oxide material fully dispersed in the water. After washing for 30 minutes, the material was filtered. While filtering, 1500kg of deionized water was added to the washing kettle again, stirring was started, and the material was returned to the washing kettle for a second washing. After washing for 30 minutes, the material was filtered again. After the filtration is completed, the water phase filtered out is sent to the sewage treatment plant for treatment. The final filtration material (filter cake) is dried at 90°C for 10 hours, and finally the material is crushed to obtain 354.11kg of white powdery dimethyl tin oxide product. After laboratory testing, the product has a tin content of 72.13%, a chlorine content of 0.075%, and a conductivity of 42.25μS / cm. Example 2

[0014] A method for preparing low-chlorine and low-conductivity dimethyl tin oxide comprises the following steps: putting 1500 kg of a dimethyl tin dichloride aqueous solution having a tin content of 26.52% and a chlorine content of 15.91% into a reactor with a steam jacket, starting stirring, then slowly and evenly dropping ammonia water for reaction, controlling the reaction temperature at 35-40°C, until the end point pH value is 8.5, and then heat-keeping for reaction for 2.5 hours. After the reaction is completed, 1000 kg of toluene is added into the reactor, and the reactor is heated to 75°C, and heat-keeping for reaction for 1.0 hour, and then standing for phase separation. After separating the lower aqueous phase, the upper layer of dimethyl tin oxide is left as a white paste distributed in toluene. Then, 2000kg of deionized water was added to the reactor, stirring was started, and then the vacuum pump was turned on to draw negative pressure to the reactor, so that the vacuum degree in the reactor reached -0.070MPa. At the same time, steam was introduced into the steam jacket of the reactor, and the temperature in the reactor was raised to 90°C to distill toluene. After the toluene was completely removed, the material was filtered to obtain dimethyl tin oxide material. The water phase filtered out was sent to the sewage treatment plant for treatment. The distilled toluene was collected by condensation and put into the next batch for use. After that, 2000kg of deionized water was added to the washing kettle, stirring was started, and then the filtered dimethyl tin oxide material was put into the washing kettle for washing. At the same time, 15kg of industrial alcohol was added to fully disperse the dimethyl tin oxide material in the water. After washing for 30 minutes, the material was filtered out. While filtering, 1500kg of deionized water was added to the washing kettle again, stirring was started, and the material was returned to the washing kettle for a second washing. After washing for 30 minutes, the material was filtered out again. After the filtration was completed, the filtered water phase was sent to the sewage treatment plant for treatment. The filtered material was dried at 90°C for 15 hours and finally crushed to obtain 546.34 kg of white powdery dimethyl tin oxide product. According to laboratory tests, the product had a tin content of 72.10%, a chlorine content of 0.057%, and an electrical conductivity of 36.72 μS / cm. Example 3

[0015] A method for preparing low-chlorine and low-conductivity dimethyl tin oxide comprises the following steps: putting 1500 kg of a dimethyl tin dichloride aqueous solution having a tin content of 26.98% and a chlorine content of 16.23% into a reactor with a steam jacket, starting stirring, then slowly and evenly dropping a sodium hydroxide solution to react, controlling the reaction temperature at 45-50°C to a final pH value of 9.5, and then heat-insulating the reaction for 1 hour. After the reaction is completed, 1050 kg of toluene is added into the reactor, and the reactor is heated to 70°C, and the reaction is continued for 1.5 hours of heat-insulating reaction, and then standing for phase separation. After separating the lower aqueous phase, the upper layer of dimethyl tin oxide is left as a white paste distributed in toluene. Then, 2000kg of deionized water was added to the reactor, stirring was started, and then the vacuum pump was turned on to draw negative pressure to the reactor, so that the vacuum degree in the reactor reached -0.070MPa. At the same time, the reactor was heated to 80°C to distill toluene. After the toluene was completely removed, the material was filtered to obtain dimethyl tin oxide material. The distilled toluene was collected by condensation and put into the next batch for use. After that, 2000kg of deionized water was added to the washing kettle, stirring was started, and the filtered dimethyl tin oxide material was put into the washing kettle for washing. At the same time, 15kg of industrial alcohol was added to fully disperse the dimethyl tin oxide material in the water. After washing for 30 minutes, the material was filtered. While filtering, 1500kg of deionized water was added to the washing kettle again, stirring was started, and the material was returned to the washing kettle for a second washing. After washing for 30 minutes, the material was filtered again. After the filtration was completed, the filtered material was dried at 100°C for 12 hours, and finally the material was crushed to obtain 556.43 kg of white powdery dimethyl tin oxide product. According to laboratory tests, the product had a tin content of 72.11%, a chlorine content of 0.052%, and a conductivity of 32.91 μS / cm. Example 4

[0016] A method for preparing low-chlorine and low-conductivity dimethyl tin oxide comprises the following steps: putting 1200 kg of a dimethyl tin dichloride aqueous solution having a tin content of 24.75% and a chlorine content of 14.82% into a reactor, starting stirring, then slowly and evenly dropping ammonia water for reaction, controlling the reaction temperature at 25-30°C, until the end point pH value is 10.0, and then heat-keeping for reaction for 2.5 hours. After the reaction is completed, 600 kg of toluene is added into the reactor, and the reactor is heated to 60°C, and heat-keeping for reaction for 2 hours, and then standing for phase separation. After separating the lower aqueous phase, the upper layer of dimethyl tin oxide is left as a white paste distributed in toluene. Then, 1600kg of deionized water was added to the reactor, stirring was started, and then the vacuum pump was turned on to draw negative pressure to the reactor, so that the vacuum degree in the reactor reached -0.050MPa. At the same time, steam was introduced into the jacket of the reactor, and the temperature in the reactor was raised to 60°C to distill toluene. After toluene was completely removed, the material was filtered to obtain dimethyl tin oxide material. The distilled toluene was collected by condensation and put into the next batch for use. After that, 1600kg of deionized water was added to the washing kettle, stirring was started, and the filtered dimethyl tin oxide material was put into the washing kettle for washing. At the same time, 12kg of industrial alcohol was added to fully disperse the dimethyl tin oxide material in the water. After washing for 30 minutes, the material was filtered. While filtering, 1500kg of deionized water was added to the washing kettle again, stirring was started, and the material was returned to the washing kettle for a second washing. After washing for 30 minutes, the material was filtered again. After the filtration was completed, the filtered material was dried at 110°C for 8 hours, and finally the material was crushed to obtain 407.23 kg of white powdery dimethyl tin oxide product. According to laboratory tests, the product had a tin content of 71.98%, a chlorine content of 0.062%, and a conductivity of 45.33 μS / cm. Example 5

[0017] A method for preparing low-chlorine and low-conductivity dimethyl tin oxide comprises the following steps: adding 1600 kg of a dimethyl tin dichloride aqueous solution having a tin content of 25.57% and a chlorine content of 15.30% into a reactor, starting stirring, then slowly and evenly dropping a sodium hydroxide solution to react, controlling the reaction temperature at 40-45°C, until the end point pH value is 8.0, and then keeping the temperature for reaction for 2 hours. After the reaction is completed, adding 1100 kg of toluene into the reactor, heating the reactor to a temperature of 65°C, continuing the keeping temperature for reaction for 1 hour, and then standing for phase separation. After separating the lower aqueous phase, a white paste of dimethyl tin oxide distributed in toluene in the upper layer is left. Then, adding 2100 kg of deionized water into the reactor, starting stirring, and then starting a vacuum pump to draw negative pressure to the reactor, so that the vacuum degree in the reactor reaches -0.060 MPa, and simultaneously introducing steam into the jacket of the reactor, raising the temperature in the reactor to 80°C to distill toluene, and after the toluene is completely removed, filtering the material by pressure to obtain a dimethyl tin oxide material. The distilled toluene is collected by condensation and put into the next batch for use. Then, 2100kg of deionized water is added to the washing kettle, stirring is started, and the filtered dimethyl tin oxide material is put into the washing kettle for washing. At the same time, 16kg of industrial alcohol is added to make the dimethyl tin oxide material fully dispersed in the water. After washing for 30 minutes, the material is filtered. While filtering, 1500kg of deionized water is added to the washing kettle again, stirring is started, and the material is returned to the washing kettle for a second washing. After washing for 30 minutes, the material is filtered again. After the filter press is completed, the filtered material is dried at 80°C for 20 hours, and finally the material is crushed to obtain 561.51kg of white powdery dimethyl tin oxide product. After laboratory testing, the product has a tin content of 72.07%, a chlorine content of 0.050%, and a conductivity of 28.81μS / cm. Example 6

[0018] A method for preparing low-chlorine and low-conductivity dimethyl tin oxide comprises the following steps: adding 1500 kg of a dimethyl tin dichloride aqueous solution having a tin content of 26.44% and a chlorine content of 15.92% into a reactor, starting stirring, then slowly and evenly dropping a sodium hydroxide solution to react, controlling the reaction temperature at 20-25°C, and heating the reactor to a pH value of 10.0 at the end point, and then keeping the temperature for reaction for 3 hours. After the reaction is completed, 900 kg of toluene is added into the reactor, and the reactor is heated to 70°C, and the temperature is kept for reaction for 1.5 hours, and then the reaction is allowed to stand for phase separation. After separating the lower aqueous phase, a white paste of dimethyl tin oxide distributed in toluene is left in the upper layer. Then, 2000 kg of deionized water is added into the reactor, stirring is started, and then a vacuum pump is turned on to draw negative pressure to the reactor, so that the vacuum degree in the reactor reaches -0.065 MPa, and at the same time, the reactor is heated, and the temperature in the reactor is raised to 50°C to distill and remove the toluene solvent, and after the toluene is completely removed, the material is filtered to obtain a dimethyl tin oxide material. The distilled toluene is collected by condensation and put into the next batch for use. Then, 2000 kg of deionized water is added to the washing kettle, stirring is started, and the filtered dimethyl tin oxide material is put into the washing kettle for washing. At the same time, 15 kg of industrial alcohol is added to fully disperse the dimethyl tin oxide material in the water. After washing for 30 minutes, the material is filtered. While filtering, 2000 kg of deionized water is added to the washing kettle again, stirring is started, and the material is returned to the washing kettle for a second washing. After washing for 30 minutes, the material is filtered again. The final filtered material is dried at 70 ° C for 26 hours, and finally the material is crushed to obtain 540.42 kg of white powdery dimethyl tin oxide product. After laboratory testing, the product has a tin content of 72.12%, a chlorine content of 0.054%, and a conductivity of 33.92 μS / cm. Example 7

[0019] A method for preparing low-chlorine and low-conductivity dimethyl tin oxide comprises the following steps: adding 1600 kg of a dimethyl tin dichloride aqueous solution having a tin content of 25.69% and a chlorine content of 15.51% into a reactor, starting stirring, then slowly and evenly dropping ammonia water for reaction, controlling the reaction temperature at 30-35°C, and heating the reactor to a pH value of 9.5 at the end point, and then keeping the temperature for reaction for 3 hours. After the reaction is completed, 1200 kg of toluene is added into the reactor, and the reactor is heated to 60°C, and the temperature is kept for reaction for 1 hour, and then the reaction is allowed to stand for phase separation. After the lower aqueous phase is separated, a white paste of dimethyl tin oxide distributed in toluene in the upper layer is left. Then, 2100 kg of deionized water is added into the reactor, stirring is started, and then a vacuum pump is turned on to draw negative pressure to the reactor, so that the vacuum degree in the reactor reaches -0.055 MPa, and steam is passed through the jacket of the reactor body at the same time, and the temperature in the reactor is raised to 85°C to distill toluene, and after the toluene is completely removed, the material is filtered by pressure to obtain the dimethyl tin oxide material. Distilled. Toluene is collected by condensation and put into the next batch for use. Then, 2100kg of deionized water is added to the water washing kettle, stirring is started, and the filtered dimethyl tin oxide material is put into the water washing kettle for washing. At the same time, 16kg of industrial alcohol is added to make the dimethyl tin oxide material fully dispersed in the water. After washing for 30 minutes, the material is filtered. While filtering, 2100kg of deionized water is added to the water washing kettle again, stirring is started, and the material is returned to the water washing kettle for a second washing. After washing for 30 minutes, the material is filtered again. After the filtration is completed, the filtered material is dried at 90°C for 15 hours, and finally the material is crushed to obtain 565.60kg of white powdery dimethyl tin oxide product. After laboratory testing, the product has a tin content of 72.14%, a chlorine content of 0.048%, and a conductivity of 25.37μS / cm.

[0020] The dimethyltin dichloride aqueous solution described in the method of the present invention can be directly purchased from the market, and the raw materials are easily available. The equipment used, such as the reaction kettle, the water washing kettle, etc., are all existing technology equipment.

Claims

1. A method for preparing low-chlorine and low-conductivity dimethyl tin oxide, characterized in that: The steps are as follows: (1) Reaction synthesis: Add dimethyltin dichloride aqueous solution into a reaction kettle, start stirring, then slowly and evenly add alkali solution to react, control the reaction temperature at 20-50°C, and the reaction end point is when the pH value reaches 8.0-10.0, and then keep the temperature for reaction for 1-3 hours; (2) Extraction of crude product: Add solvent toluene into the reaction kettle and heat the reaction kettle to 60-80°C. Keep the temperature for 1-2 hours and then allow the reaction to stand for phase separation. After the lower aqueous phase is separated, the upper layer is a white paste of dimethyltin oxide distributed in toluene. (3) Solvent removal: Add deionized water into the reaction kettle, start stirring, and then distill toluene at a temperature of 50-90°C and a vacuum degree of -0.050-0.070 MPa. After the toluene is completely removed, filter the material to obtain dimethyl tin oxide material; (4) Adequate water washing: Add deionized water to the water washing kettle, start stirring, and then put the filtered dimethyl tin oxide material into the water washing kettle for water washing. At the same time, add a small amount of industrial alcohol to fully disperse the dimethyl tin oxide material in the water, improve the water washing effect, and thus better remove the residual chloride ions and alkali metal ions; after water washing, filter the material, and at the same time, add deionized water to the water washing kettle again, start stirring, and then return the material to the water washing kettle for a second water washing. After the second water washing, filter the material again; (5) Drying and crushing: The filtered material is dried at 70-110°C until the moisture content reaches the required level, and then the material is crushed to obtain a low-chlorine and low-conductivity dimethyl tin oxide product with a chlorine content of less than 0.1% and a conductivity of less than 50 μS / cm.

2. The method for preparing a low-chlorine and low-conductivity dimethyl tin oxide according to claim 1, characterized in that: The alkali solution used in step (1) is sodium hydroxide solution or ammonia water.

3. The method for preparing a low-chlorine and low-conductivity dimethyl tin oxide according to claim 1, characterized in that: The amount of toluene used in step (2) is 50% to 100% of the mass of the dimethyltin dichloride aqueous solution.

4. The method for preparing a low-chlorine and low-conductivity dimethyl tin oxide according to claim 1, characterized in that: The toluene distilled in step (3) is recovered by condensation and then recycled.

5. The method for preparing a low-chlorine and low-conductivity dimethyl tin oxide according to claim 1, characterized in that: The amount of industrial alcohol used in step (4) is 1% by mass of the dimethyltin dichloride aqueous solution.

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