Method for gas-phase synthesis of zinc peroxide

Abstract

The invention discloses a method for gas-phase synthesis of zinc peroxide, which comprises the following steps: (1) fully and uniformly mixing zinc carbonate powder and carbonic anhydrase, and activating a zinc carbonate precursor through carbonic anhydrase; (2) introducing chlorine dioxide gas phase oxidation reactants, adding a certain amount of ascorbic acid, and carrying out a synchronous reaction; (3) synchronously introducing the generated tail gas into a tail gas absorption device; (4) the stable product is rapidly cooled through low-temperature nitrogen, meanwhile, silicon nitride is added for cooperation to enable the zinc peroxide to be stably solidified, and a high-purity ZnO2 product is obtained.The process for synthesizing the zinc peroxide through the gas phase has the following advantages that the process steps are simple and convenient, and the efficiency is high; (2) the product stability is good; (3) the zinc peroxide is high in purity and fine in particle size; the method is an efficient and green zinc peroxide synthesis method, and can meet the requirements of industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of zinc peroxide preparation, and particularly relates to a method for synthesizing zinc peroxide in a vapor phase. Background Art

[0002] Zinc peroxide, whose molecular formula is ZnO 2 Zinc peroxide can be used as a vulcanization accelerator, preservative, disinfectant, dispersant, etc. It is also used in the manufacture of cosmetics, medicines, preservatives, astringents, and zinc peroxide as a catalyst in multiple catalytic reactions, especially in organic synthesis, environmental catalysis and other reactions.

[0003] Various existing technical data show that the synthesis method of zinc peroxide is mainly a liquid phase method: zinc salt, zinc hydroxide, zinc oxide and other zinc-containing substances are used to react with hydrogen peroxide solution, and the zinc substance and hydrogen peroxide solution are mixed and reacted through a large amount of aqueous solution medium, and the temperature is reduced by a cooling device, and various process parameters are controlled for reaction synthesis, and finally the solid-liquid separation is carried out and the finished product is obtained by drying.

[0004] The existing preparation method has the following technical defects: (1) Poor quality of zinc peroxide products: The zinc peroxide prepared by the existing process has a purity of 50-60%, and the particle size is relatively coarse, and the application field is narrow.

[0005] (2) Poor product stability: When testing the stability of zinc peroxide at a certain temperature, the purity of the product prepared by the existing method decreases rapidly.

[0006] (3) Low efficiency of wet reaction: Under the same output conditions, the existing process method is time-consuming and the process route is complicated.

[0007] In view of this, studying a new method for synthesizing zinc peroxide has important practical significance. Summary of the invention

[0008] In view of the above problems, the present invention provides a method for vapor phase synthesis of zinc peroxide, which is an efficient and green method for synthesizing zinc peroxide, can meet the needs of industrial production, and solve the problems of poor product quality, poor stability, low production efficiency and complex process existing in the existing process.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is: A method for synthesizing zinc peroxide in a vapor phase comprises the following process: S1: Preparation of zinc carbonate raw materials: Add zinc carbonate powder and carbonic anhydrase into the reactor, turn on the stirring device of the reactor, and stir at a certain speed for a period of time to fully mix the zinc carbonate powder and carbonic anhydrase; when both are solid, carbonic anhydrase can slowly promote the decomposition of zinc carbonate, which is beneficial to subsequent reactions and provides a prerequisite for the generation of zinc peroxide with finer particles.

[0010] S2: introducing chlorine dioxide gas: while the stirring of the reactor is continuously turned on, the stirring speed of the reactor is adjusted, and chlorine dioxide gas is introduced into the reactor at the same time. During the process of introducing chlorine dioxide gas, a certain amount of ascorbic acid is added into the reactor through the feeding device. Ascorbic acid simultaneously induces chlorine dioxide to produce the active substance singlet oxygen. The active ingredient is an excited oxygen molecule with strong selectivity and reactivity. It can play a strong activation role in the slowly decomposed zinc carbonate in the gas phase atmosphere, and further form the product zinc peroxide.

[0011] S3: The tail gas generated during the reaction is simultaneously introduced into the tail gas absorption device; the tail gas generated during the reaction, including a small amount of incompletely reacted chlorine dioxide, carbon dioxide and other substances, is quickly sucked into the tail gas absorption device. This process can absorb all the tail gas, which is more conducive to the forward reaction and greatly shortens the time for synthesizing the effective ingredient zinc peroxide. On the other hand, it can make the process environmentally friendly and feasible, and the process is healthy, green and pollution-free.

[0012] S4: After the reaction is completed, the temperature is 30-40°C. At this time, the zinc peroxide product is still in a non-stable state. A large amount of nitrogen gas at -5~5°C is quickly introduced. Under the condition of rapid cooling, the product is rapidly cooled and stabilized by low-temperature nitrogen. While introducing nitrogen, a small amount of silicon nitride is added as a stabilizer to cooperate with zinc peroxide to obtain stable solidification, that is, the product is obtained. At the same time, the low-temperature nitrogen introduced ensures that the unreacted chlorine dioxide gas and tail gas are sent to the tail gas absorption device together.

[0013] According to a further technical solution, in step S1, the amount of carbonic anhydrase added is 0.5-1% of the mass of zinc carbonate added, the mixing speed is 20-80 r / min, and the stirring time is 5-10 min.

[0014] Further technical solution, in step S2, the stirring speed is adjusted to 130-160r / min, the introduction rate of chlorine dioxide gas is set to 2.2-3kg / min, the reaction time is 20-60min, and the reaction pressure is less than 5Mpa.

[0015] According to a further technical solution, in step S2, the amount of ascorbic acid added is 0.5-1.5% of the mass of zinc carbonate added.

[0016] According to a further technical solution, the tail gas absorption device is a liquid alkali absorption tank.

[0017] According to a further technical solution, the nitrogen cooling temperature in step S4 is -5~5°C.

[0018] According to a further technical solution, in step S4, the amount of silicon nitride added is 0.1% of the mass of zinc carbonate added.

[0019] The reaction mechanism equation of this process is as follows: ZnCO 3 +ClO 2 →ZnO 2 +ClO+CO 2 .

[0020] The present invention solves the following technical problems in the existing process:

[0021] (1) The present invention solves the problem of poor product quality of existing processes: the purity of zinc peroxide products obtained by existing processes is generally only 50-60%, and its active finished products lack applicability in some fields with relatively high requirements. At the same time, the particle size of zinc peroxide in existing processes is too large, which is also limited in practical applications.

[0022] (2) The present invention solves the problem of poor stability of products produced by existing processes: the purity of zinc peroxide produced by existing processes decreases too quickly in stability tests, so there is a certain risk in the actual transportation process. The products produced by the present invention can greatly improve the stability and solve the related problems to a certain extent.

[0023] (3) The present invention solves the problem of low production efficiency and complex process of existing process products: the zinc peroxide prepared by the existing production process requires a large amount of water as a medium. After the zinc salt, zinc oxide, or zinc hydroxide are evenly dispersed, hydrogen peroxide is added. After the reaction is completed, it is necessary to filter and wash, and finally dry to obtain the product. The reaction process is too complicated. The process steps of the present invention are relatively simple and the synthesis efficiency is high.

[0024] (4) The present invention solves the problem of coarse zinc peroxide particle size in the existing process: zinc oxide is slowly induced by carbonic anhydrase to form zinc carbonate: this process ensures that zinc oxide can form zinc peroxide crystal nuclei at a relatively slow rate at the microscopic level, and the growth rate of the particles can be controlled. At the same time, the carbon dioxide produced and itself exist in the gas phase reaction environment, further avoiding the agglomeration of the product zinc peroxide. Therefore, the zinc peroxide particle size of the present invention is finer and more uniform.

[0025] Compared with the prior art, the present invention has the following technical effects through the vapor phase synthesis of zinc peroxide: (1) The process is simple and efficient: the reaction process does not require mass transfer through liquid phase substances, and no filter cake will be formed, and there is no need for filter pressing and drying.

[0026] (2) Good product stability: Cold nitrogen is used to rapidly cool the reaction at the end point, and at the same time, a decomposition-resistant stabilizer, silicon nitride, is added. It has high-temperature resistance and antioxidant properties and adheres to the surface of zinc peroxide. It has a good stabilizing and solidifying effect on a large number of non-stable zinc peroxide products, and can extend the service life and effect in practical application fields such as environmental catalytic repair and medical disinfection.

[0027] (3) High purity of zinc peroxide: The purity of zinc peroxide prepared by the gas phase reaction method reaches more than 90%. Under the condition of high conversion rate, the obtained zinc peroxide has high purity.

[0028] (4) Finer and more uniform particle size: The particle size of zinc peroxide prepared by the gas phase reaction method is 100-150μm, which is finer than that of the ordinary process. DETAILED DESCRIPTION

[0029] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0030] Example 1

[0031] A method for synthesizing zinc peroxide in a vapor phase comprises the following process: 1. Zinc carbonate pretreatment: prepare 125kg zinc carbonate in advance, add it to the conical reactor, turn on the stirring speed to 40r / min, then add 1kg carbonic anhydrase, continue stirring to ensure uniform mixing, let it be fully mixed with zinc carbonate, stir for 5 minutes. When both are solid, carbonic anhydrase can slowly promote the decomposition of zinc carbonate, thereby promoting subsequent reactions and providing a prerequisite for the generation of finer zinc oxide particles.

[0032] 2. Chlorine dioxide oxidation reaction: The reactor is continuously stirred and the stirring speed is increased to 130r / min. At the same time, the chlorine dioxide gas cylinder is connected to the mass flow meter, and the gas introduction rate is set to 2.72kg / min. The reaction time is 25min. Note that the overall pressure of the reactor does not exceed 5Mpa. During the process of introducing the gas, 1kg of ascorbic acid is added through the feeding device to synchronously induce chlorine dioxide to produce singlet oxygen. This active ingredient can play a strong activation role in the gas phase atmosphere to further form the product zinc peroxide.

[0033] 3. Tail gas absorption: A sodium hydroxide liquid alkali absorption tank is set up. The tail gas generated during the reaction, including a small amount of chlorine dioxide, carbon dioxide and other substances, is quickly sucked into the liquid alkali absorption tank. This process can absorb all the tail gas, which is more conducive to the forward reaction and greatly shortens the time for synthesizing the effective ingredient zinc peroxide. On the other hand, it makes the process environmentally friendly and feasible, and the process is healthy, green and pollution-free. The tail gas absorption time is synchronized with the reaction time.

[0034] 4. Rapid cooling with cold nitrogen to stabilize the product: After the above reaction is completed, the temperature is 30-40°C. At this time, the zinc peroxide product produced is still in a non-stable state. A large amount of nitrogen at -5 degrees Celsius is quickly introduced. Under the condition of rapid cooling, 0.125 kg of silicon nitride is added at the same time to cooperate with the zinc peroxide to obtain stable solidification and structural stability. At the same time, the low-temperature nitrogen ensures that the remaining incompletely reacted chlorine dioxide and some tail gas are sent to the tail gas absorption device together for 5 minutes to finally obtain the finished zinc peroxide.

[0035] 5. Reaction process of this embodiment: the total reaction time is 35 min, and 97.83 kg of zinc peroxide is obtained, with a purity of 98.12%, and a particle size (D50, μm): 128.3 μm.

[0036] Example 2

[0037] 1. Zinc carbonate pretreatment: Prepare 125kg zinc carbonate in advance, add it to the conical reactor, turn on the stirring speed to 60r / min, then add 1kg carbonic anhydrase, continue stirring to ensure uniform mixing, let it be fully mixed with zinc carbonate, stir for 5 minutes. When both are solid, carbonic anhydrase can slowly promote the decomposition of zinc carbonate, thereby promoting subsequent reactions and providing a prerequisite for the generation of finer zinc oxide particles.

[0038] 2. Chlorine dioxide oxidation reaction: The reactor is continuously stirred and the stirring speed is increased to 140r / min. At the same time, the chlorine dioxide gas cylinder is connected to the mass flow meter, and the gas introduction rate is set to 2.83kg / min. The reaction time is 24min. Note that the overall pressure of the reactor does not exceed 5Mpa. During the process of introducing the gas, 1.25kg of ascorbic acid is added through the feeding device to synchronously induce chlorine dioxide to produce singlet oxygen. This active ingredient can play a strong activation role in the gas phase atmosphere, corresponding to the slowly decomposed zinc carbonate, and further form the product zinc peroxide.

[0039] 3. Tail gas absorption: A sodium hydroxide liquid alkali absorption tank is set up. The tail gas generated during the reaction, including a very small amount of chlorine dioxide, carbon dioxide and other substances, is quickly sucked into the liquid alkali absorption tank. This process can absorb all the tail gas, which is more conducive to the forward reaction and greatly shortens the time for synthesizing the effective ingredient zinc peroxide. On the other hand, it makes the process environmentally friendly and feasible, and the process is healthy, green and pollution-free. The tail gas absorption time is synchronized with the reaction time.

[0040] 4. Rapid cooling with cold nitrogen to stabilize the product: After the above reaction is completed, the temperature is 30-40°C. At this time, the zinc peroxide product produced is still in a non-stable state. Rapidly introduce a large amount of nitrogen at -5 degrees Celsius, and quickly cool it down. At the same time, add 0.125kg of silicon nitride to cooperate with the zinc peroxide to obtain stable solidification and structural stability. At the same time, the inert gas will send the remaining incompletely reacted chlorine dioxide and some tail gas into the tail gas absorption device for 5 minutes to finally obtain the finished zinc peroxide.

[0041] 5. Reaction process of this example: the total reaction time is 34 min, and 97.8 kg of zinc peroxide is obtained with a purity of 97.95% and a particle size (D50, μm): 130.2 μm.

[0042] Comparative Example 1

[0043] Existing process for preparing zinc peroxide: 1. Add 300 kg of tap water as the base medium into the autoclave reaction vessel and start stirring at 100 r / min.

[0044] 2. Add 125 kg of zinc carbonate to the reactor and stir for 10 minutes.

[0045] 3. Prepare 100 kg of 35% hydrogen peroxide in advance, slowly add it into the system, use frozen brine to control the temperature of the reaction system at 30-38°C, and the reaction time is 40 minutes.

[0046] 4. Then enter the plate frame and press dry for 30 minutes.

[0047] 5. After the plate and frame filtration is completed, the wet zinc peroxide is conveyed through a conveyor belt and dried in a dryer to obtain the finished product, which takes 40 minutes.

[0048] 6. Reaction history of this comparative example: The reaction time was 120 min, and 90.5 kg of zinc peroxide was obtained with a purity of 59.2%, and a particle size (D50, μm): 500.2 μm.

[0049] Comparative Example 2 1. Zinc carbonate pretreatment: Prepare 125 kg of zinc carbonate in advance, add it into the conical reactor, turn on the stirring speed to 60 r / min, and stir for 5 minutes.

[0050] 2. Chlorine dioxide oxidation reaction: While the reactor is stirring, increase the speed to 140r / min. At the same time, connect the chlorine dioxide gas cylinder to the mass flow meter, set the gas introduction rate to 2.83kg / min, and the reaction time to 24min. Note that the overall pressure of the reactor does not exceed 5Mpa. During the process of introducing the gas, 1.25kg of ascorbic acid is added to the zinc carbonate mass fraction through the feeding device.

[0051] 3. Tail gas absorption: A sodium hydroxide liquid alkali absorption tank is set up. The tail gas generated during the reaction process will quickly absorb a small amount of chlorine dioxide, carbon dioxide and other gases into the liquid alkali absorption tank. This process can absorb all the tail gas, which is more conducive to the forward reaction and greatly shortens the time for synthesizing the effective ingredient zinc peroxide.

[0052] 4. Rapid cooling with cold nitrogen to stabilize the product: After the above reaction is completed, the temperature is 30-40°C. At this time, the zinc peroxide product produced is still in a non-stable state. Rapidly introduce a large amount of nitrogen at -5 degrees Celsius, and quickly cool it down. At the same time, add 0.125kg of silicon nitride to cooperate with the zinc peroxide to obtain stable solidification and structural stability. At the same time, the inert gas ensures that the remaining incompletely reacted chlorine dioxide and some tail gas are sent to the tail gas absorption device together. Continue for 5 minutes to finally obtain the finished zinc peroxide.

[0053] 5. Reaction history of this comparative example: the total reaction time is 34 min, and 97.67 kg of zinc peroxide is obtained, with a purity of 97.26% and a particle size (D50, μm): 380.1 μm.

[0054] Comparative Example 3 1. Zinc carbonate pretreatment: Prepare 125 kg of zinc carbonate in advance, add it to the conical reactor, turn on the stirring speed to 40 r / min, then add 1 kg of carbonic anhydrase, continue stirring to ensure uniform mixing, let it be fully mixed with zinc carbonate, and stir for 5 minutes.

[0055] 2. Chlorine dioxide oxidation reaction: While the reactor is stirring continuously, increase the speed to 140r / min. At the same time, connect the chlorine dioxide gas cylinder to the mass flow meter, set the gas introduction rate to 2.83kg / min, and the reaction time to 24min. Note that the overall pressure of the reactor does not exceed 5Mpa.

[0056] 3. Tail gas absorption: A sodium hydroxide liquid alkali absorption tank is set up. The tail gas generated during the reaction, including a small amount of chlorine dioxide, carbon dioxide and other substances, is quickly sucked into the liquid alkali absorption tank. This process can absorb all the tail gas, which is more conducive to the forward reaction and greatly shortens the time for synthesizing the effective ingredient zinc peroxide.

[0057] 4. Rapid cooling with cold nitrogen to stabilize the product: After the above reaction is completed, the temperature is 30-40°C. At this time, the zinc peroxide product produced is still in a non-stable state. Rapidly introduce a large amount of nitrogen at -5 degrees Celsius, and quickly cool it down. At the same time, add 0.125kg of silicon nitride to cooperate with the zinc peroxide to obtain stable solidification and structural stability. At the same time, the inert gas ensures that the remaining incompletely reacted chlorine dioxide and some tail gas are sent to the tail gas absorption device together. Continue for 5 minutes to finally obtain the finished zinc peroxide.

[0058] 5. Reaction history of this comparative example: the total reaction time is 34 min; 94.7 kg of zinc peroxide is obtained, with a purity of 81.3% and a particle size (D50, μm): 150.1 μm.

[0059] The experimental results are compared in Table 1: Table 1 Information of reaction products of different examples and comparative examples

[0060] The zinc peroxide prepared above was tested for stability, and the experimental results are shown in Table 2 below: The stability test conditions are as follows: (1) Place 30 g of zinc peroxide in a 50 ml stoppered test tube; (2) Place the test tube containing the sample in a 60°C constant temperature electric heating box and test the change in the purity of zinc peroxide under continuous high temperature.

[0061] Stability data test: Stability on the Nth day = zinc peroxide purity on the Nth day / zinc peroxide purity on the first day * 100%.

[0062] Table 2 Stability test information of different embodiments and comparative examples

[0063] According to the above two table data, it can be concluded that the present invention is beneficial in that: (1) Improving reaction efficiency: It can be seen from the experiments and data of Examples 1 and 2 and Comparative Example 1 that the present invention utilizes gas phase reaction, simplifies multiple reaction steps, and shortens the reaction time by about 85 minutes.

[0064] (2) Better product stability: It can be seen from the tests and data of Examples 1 and 2 and Comparative Example 1 that, on the one hand, the zinc peroxide synthesized by the wet method has low purity and many impurities; on the other hand, the present invention uses cold nitrogen to stabilize and solidify the newly synthesized and non-stable substances. Therefore, it performs better in the stability test.

[0065] (3) The product has finer and more uniform particle size: The control test and data of Examples 1 and 2 and Comparative Example 2 show that, because the present invention uses carbonic anhydrase to pretreat zinc carbonate, it ensures that zinc carbonate is slowly decomposed into zinc oxide, and then zinc peroxide crystal nuclei can be formed at a relatively slow rate at the microscopic level, and the growth rate of the particles can be controlled; at the same time, the carbon dioxide generated and the reaction exist in a gas phase reaction environment, which further avoids the agglomeration of the product zinc peroxide. Therefore, the product of the present invention has finer and more uniform particle size.

[0066] (4) Zinc peroxide has a higher purity: The control tests and data of Examples 1 and 2 and Comparative Examples 1 and 3 show that the present invention combines chlorine dioxide with ascorbic acid to continuously produce highly active reaction substances such as singlet oxygen during the reaction process, which helps to make the synthesized product higher in purity.

[0067] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for vapor phase synthesis of zinc peroxide, characterized in that: Including the following processes: S1: Preparation of zinc carbonate raw material: Add zinc carbonate powder and carbonic anhydrase into the reactor, turn on the stirring device of the reactor, and stir at a certain speed for a period of time to fully mix the zinc carbonate powder and carbonic anhydrase; S2: introducing chlorine dioxide gas: adjusting the stirring speed of the reactor, and introducing chlorine dioxide gas into the reactor at the same time. During the process of introducing chlorine dioxide gas, a certain amount of ascorbic acid is added into the reactor through the feeding device to react synchronously; S3: Synchronously introducing the tail gas generated during the reaction into the tail gas absorption device; S4: After the reaction is completed, the product is rapidly cooled and stabilized by low-temperature nitrogen, and at the same time, a stabilizer, silicon nitride, is added to coordinate and stabilize the zinc peroxide to obtain the final product, and the low-temperature nitrogen introduced ensures that the unreacted chlorine dioxide gas and tail gas are sent to the tail gas absorption device together.

2. A method for vapor phase synthesis of zinc peroxide according to claim 1, characterized in that: In step S1, the amount of carbonic anhydrase added is 0.5-1% of the mass of zinc carbonate added, the mixing speed is 20-80 r / min, and the stirring time is 5-10 min.

3. A method for vapor phase synthesis of zinc peroxide according to claim 1, characterized in that: In step S2, the stirring speed is adjusted to 130-160 r / min, the introduction rate of chlorine dioxide gas is set to 2.2-3 kg / min, the reaction time is 20-60 min, and the reaction pressure is less than 5 MPa.

4. A method for vapor phase synthesis of zinc peroxide according to claim 3, characterized in that: In step S2, the amount of ascorbic acid added is 0.5-1.5% of the mass of zinc carbonate added.

5. A method for vapor phase synthesis of zinc peroxide according to claim 1, characterized in that: The tail gas absorption device is a liquid alkali absorption storage tank.

6. The method for vapor phase synthesis of zinc peroxide according to claim 1, characterized in that: The nitrogen cooling temperature in step S4 is -5~5°C.

7. The method for vapor phase synthesis of zinc peroxide according to claim 1, characterized in that: In step S4, the amount of stabilizer silicon nitride added is 0.1% of the mass of zinc carbonate.

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