Preparation of ozone inhibitor

Abstract

The invention relates to preparation of an ozone inhibitor, and belongs to the technical field of environmental catalytic material and high polymer material protection. Comprising the following steps: 1, preparing raw materials: selecting a manganese dioxide catalytic core which accounts for 80-98% of the total weight and has a mesoporous structure, and selecting a thiourea chemical scavenger which accounts for 2-20% of the total weight and is loaded on the catalytic core; 2, mixing and dissolving: adding the thiourea chemical scavenger and the manganese dioxide catalytic core into a proper amount of organic solvent for dissolving, and dispersing in an ultrasonic cleaner to uniformly mix; 3, removing the organic solvent; and 4, vacuum drying. The material has the advantages of synergistic interaction, ultrahigh efficiency, improvement of the removal rate and total capacity of ozone in a'catalysis + chemistry 'two-channel mode, optimized structure, stable performance and dual functions, ensures long-term catalytic activity and structural stability, not only serves as an efficient air purification material, but also serves as a rubber anti-ozone agent with excellent performance, is green and environment-friendly, has low pollution, and is suitable for industrial production. The environment friendliness is higher.

Description

Technical Field

[0001] This invention relates to the preparation of an ozone inhibitor, belonging to the field of environmental catalytic materials and polymer material protection technology. Background Technology

[0002] Ozone (O3) is a highly oxidizing gas and a common air pollutant near the Earth's surface, posing a threat to human health and the ecological environment. It is also a major factor contributing to the aging and cracking of polymer materials such as rubber and plastics. Therefore, developing efficient ozone blocking technologies is of significant practical importance.

[0003] Currently, technologies for removing ozone from the air are mainly divided into physical adsorption, chemical absorption, and catalytic decomposition. While physical adsorbents such as activated carbon can adsorb ozone, their capacity is limited, they are easily saturated, and there is a risk of desorption. Chemical absorption methods may generate secondary pollutants. In contrast, catalytic decomposition is considered the most promising technology, capable of efficiently decomposing ozone into harmless oxygen under mild conditions. Among numerous catalysts, transition metal oxides based on manganese dioxide (MnO2) have attracted considerable attention due to their low cost and high activity. However, traditional MnO2 catalysts are difficult to precisely control in terms of specific surface area, pore structure, and crystal form during preparation, and their activity tends to decrease under high humidity conditions, limiting their lifespan. Furthermore, some studies have begun exploring the use of biological enzymes (such as catalase and superoxide dismutase) for ozone degradation. While these methods are environmentally friendly, the enzymes have poor stability and high costs, making large-scale industrial application difficult.

[0004] In the field of material protection, ozone inhibitors are typically added to polymeric materials (especially rubber) to delay aging. The mainstream ozone inhibitors are mainly p-phenylenediamine derivatives (such as IPPD, N-isopropyl-N'-phenyl-p-phenylenediamine) and thiourea compounds. P-phenylenediamine-based ozone inhibitors offer significant protection but are polluting, easily discolor products, and possess some biotoxicity. Thiourea-based ozone inhibitors (such as N,N'-dipiperidinylthiourea), as a novel type of ozone inhibitor, are less polluting, but their protective durability under harsh dynamic stress conditions still has room for improvement when used alone.

[0005] In summary, existing technologies, whether applied to air purification or material protection, each have their own limitations. Air purification catalysts suffer from humidity sensitivity and activity decay, resulting in unstable performance, while ozone inhibitors struggle to balance protective efficacy and environmental friendliness. Therefore, this invention provides a method for preparing an ozone inhibitor. Summary of the Invention

[0006] In view of this, the present invention provides a method for preparing an ozone inhibitor that achieves synergistic effects and extremely high efficiency. The "catalytic + chemical" dual-channel mode greatly improves the ozone removal rate and total capacity. The optimized structure and stable performance ensure its long-term catalytic activity and structural stability. It has dual functions, serving not only as a highly efficient air purification material but also as a high-performance rubber anti-ozone agent. It is green, environmentally friendly, and has low pollution and higher environmental friendliness.

[0007] This invention provides a method for preparing an ozone inhibitor, the technical solution of which includes the following steps:

[0008] Step 1: Raw material preparation: Select a manganese dioxide catalyst core with a mesoporous structure, accounting for 80%-98% of the total weight, and select a thiourea-based chemical scavenger loaded on the catalyst core, accounting for 2%-20% of the total weight.

[0009] Step 2: Mixing and dissolving: Add the thiourea chemical cleaner and the manganese dioxide catalyst core to an appropriate amount of organic solvent to dissolve them, so as to achieve the composite of the thiourea chemical cleaner and the manganese dioxide catalyst core. Disperse them in an ultrasonic cleaner to make them evenly mixed.

[0010] Step 3: Organic solvent removal: Transfer the well-mixed solution to a rotary evaporator and remove the organic solvent by vacuum stirring under water bath to obtain solid powder;

[0011] Step 4: Vacuum drying: The obtained solid powder is dried under a vacuum to obtain the ozone inhibitor product of the present invention.

[0012] Furthermore, the BET specific surface area of ​​the manganese dioxide catalytic core in step one is 140 m². 2 / g-180m 2 / g.

[0013] Furthermore, the preparation of the mesoporous manganese dioxide catalytic core in step one employs the sol-gel method, with the specific steps as follows:

[0014] a) Dissolve manganese acetate tetrahydrate in deionized water to form a precursor solution;

[0015] b) Add citric acid to the precursor solution and stir in a water bath at a certain temperature to form a homogeneous sol;

[0016] c) Slowly add ammonia water dropwise while stirring to adjust the pH value of the solution, and continue stirring to age and form a gel for 10-12 hours;

[0017] d) Wash the solid alternately with deionized water and anhydrous ethanol until neutral, centrifuge, and dry the solid at 90-120℃;

[0018] e) The dried solid is heated and calcined in an air atmosphere, and after being calcined at a constant temperature for a period of time, mesoporous manganese dioxide powder with high catalytic activity is obtained.

[0019] Furthermore, in step b, the water bath stirring temperature is 60℃-80℃, in step c, the solution pH is adjusted to 8-10, in step e, the calcination temperature is 380℃-420℃, and the constant temperature calcination time is 3-5 hours.

[0020] Furthermore, the thiourea chemical scavenger in step one is N,N′-dipiperidinylthiourea.

[0021] Furthermore, the preparation of the thiourea-based chemical scavenger in step one employs a microwave-assisted method, the specific steps of which are as follows:

[0022] a) Thiourea and hexahydropyridine are mixed in anhydrous ethanol solvent at a molar ratio of 1:2.2;

[0023] b) Place the mixed solution in a microwave reactor for irradiation reaction;

[0024] c) After the reaction is complete, the mixture is cooled, filtered, washed and dried to obtain a high-purity white powder of N,N′-dipiperidinylthiourea.

[0025] Furthermore, in step b, the microwave power in the microwave reactor is 260W-320W, the temperature is 50℃-60℃, and the radiation reaction time is 8-10min.

[0026] Furthermore, the organic solvent in step two is one of toluene, ethanol, etc., which can be used to ensure that the thiourea chemical scavenger and manganese dioxide catalyst core are fully dissolved without affecting the performance of the ozone inhibitor.

[0027] Furthermore, the dispersion time in the ultrasonic cleaner in step two is 20-40 minutes, the water bath temperature in step three is 45℃-70℃, and the vacuum drying temperature in step four is 70℃-85℃ for 3.5-4.5 hours.

[0028] The beneficial effects of this invention are:

[0029] This invention provides a method for preparing an ozone inhibitor that achieves synergistic effects and extremely high efficiency. The "catalytic + chemical" dual-channel mode greatly enhances the ozone removal rate and total capacity. The optimized structure and stable performance ensure long-term catalytic activity and structural stability. It has dual functions, serving not only as a highly efficient air purification material but also as a high-performance rubber anti-ozone agent. It is green, environmentally friendly, and has low pollution and higher environmental friendliness. Detailed Implementation

[0030] The preferred embodiments of the present invention will now be described in detail.

[0031] This invention provides a method for preparing an ozone inhibitor, which includes the following steps:

[0032] Step 1: Raw material preparation: Select manganese dioxide catalyst core with mesoporous structure, accounting for 80%-98% of the total weight, and select thiourea chemical scavenger loaded on the catalyst core, accounting for 2%-20% of the total weight;

[0033] Step 2: Mixing and Dissolving: Add the thiourea chemical scavenger and manganese dioxide catalyst core to an appropriate amount of organic solvent for dissolution. The organic solvent can be one of toluene, ethanol, etc., which can ensure that the thiourea chemical scavenger and manganese dioxide catalyst core are fully dissolved without affecting the performance of the ozone inhibitor, so as to achieve the composite of thiourea chemical scavenger and manganese dioxide catalyst core. Disperse in an ultrasonic cleaner for 20-40 minutes to make it evenly mixed.

[0034] Step 3: Organic solvent removal: Transfer the well-mixed solution to a rotary evaporator and remove the organic solvent by vacuum stirring in a water bath at 45℃-70℃ to obtain a solid powder;

[0035] Step 4: Vacuum drying: The obtained solid powder is dried at 70℃-85℃ under vacuum for 3.5-4.5 hours to obtain the ozone inhibitor product of the present invention.

[0036] As an optional embodiment, the BET specific surface area of ​​the manganese dioxide catalytic core in step one is 140 m². 2 / g-180m 2 / g, the preparation of the mesoporous manganese dioxide catalytic core in step one adopts the sol-gel method, and the specific steps are as follows:

[0037] a) Dissolve manganese acetate tetrahydrate in deionized water to form a precursor solution;

[0038] b) Add citric acid to the precursor solution and stir in a water bath at 60℃-80℃ to form a homogeneous sol;

[0039] c) Slowly add ammonia water dropwise while stirring to adjust the pH of the solution to 8-10, and continue stirring to age and form a gel for 10-12 hours;

[0040] d) Wash the solid alternately with deionized water and anhydrous ethanol until neutral, centrifuge, and dry the solid at 90-120℃;

[0041] e) The dried solid is calcined in air at 380℃-420℃ and kept at a constant temperature for 3-5 hours to obtain mesoporous manganese dioxide powder with high catalytic activity.

[0042] As an optional embodiment, in step one, the thiourea chemical scavenger is N,N′-dipiperidinylthiourea, and the preparation of the thiourea chemical scavenger in step one is carried out using a microwave-assisted method, the specific steps of which are as follows:

[0043] a) Thiourea and hexahydropyridine are mixed in anhydrous ethanol solvent at a molar ratio of 1:2.2;

[0044] b) Place the mixed solution in a microwave reactor for radiation reaction, with microwave power of 260W-320W, temperature of 50℃-60℃, and radiation reaction time of 8-10min;

[0045] c) After the reaction is complete, the mixture is cooled, filtered, washed and dried to obtain a high-purity white powder of N,N′-dipiperidinylthiourea.

[0046] Example 1: Preparation of mesoporous manganese dioxide catalytic core (component A)

[0047] 20.0 g of manganese acetate tetrahydrate (Mn(CH3COO)2·4H2O) was dissolved in 500 mL of deionized water, and 15.0 g of citric acid was added. The mixture was stirred in a 70 °C water bath for 30 minutes to form a clear pink sol. Under vigorous stirring, 10% ammonia was added dropwise to adjust the pH to 9.0, and a brown precipitate was observed to form. The mixture was stirred and aged at 70 °C for 2 hours to form a homogeneous gel. The gel was washed alternately with deionized water and anhydrous ethanol until neutral, and then centrifuged. The obtained solid was dried in an oven at 110 °C for 12 hours. Finally, the dried powder was placed in a muffle furnace and heated to 400 °C at a rate of 5 °C / min, and calcined at this temperature for 4 hours. After natural cooling to room temperature, 10.2 g of dark brown mesoporous manganese dioxide powder was obtained. BET analysis showed that its specific surface area was 165.2 m². 2 / g, with an average pore size of 8.7nm.

[0048] Example 2: Preparation of the chemical scavenger N,N′-dipiperidinylthiourea (component B)

[0049] In a 250 mL microwave-safe reaction tube, 3.8 g (0.05 mol) of thiourea and 10.6 g (0.125 mol) of hexahydropyridine (molar ratio approximately 1:2.2) were added, along with 100 mL of anhydrous ethanol as the solvent. The reaction tube was sealed and placed in a microwave-safe chemical reactor. The reaction temperature was set to 55 °C, the microwave power to 300 W, and the reaction time was 9 minutes. After the reaction was complete, the reaction solution was cooled to room temperature, and a large amount of white crystals precipitated. After filtration, washing with a small amount of cold ethanol, and vacuum drying, 10.5 g of white needle-like crystals of N,N′-dipiperidinylthiourea were obtained, with a yield of 92%.

[0050] Example 3: Preparation of composite ozone inhibitors

[0051] Take 9.5 g of mesoporous manganese dioxide (component A) prepared in Example 1 and 0.5 g of N,N′-dipiperidinylthiourea (component B) prepared in Example 2 (mass ratio 95:5), and dissolve component B in 50 mL of anhydrous ethanol. Add component A powder to the solution and disperse in an ultrasonic cleaner for 30 minutes to ensure homogeneity. Subsequently, transfer the mixture to a rotary evaporator and remove the ethanol under reduced pressure in a 60°C water bath. Finally, vacuum dry the resulting solid powder at 80°C for 4 hours to obtain the composite ozone inhibitor product of this invention.

[0052] Example 4: Air purification performance test of composite ozone inhibitor

[0053] Ozone was generated in a 30L sealed glass test chamber using an ozone generator, and its initial concentration was stabilized at 5.0 ppm. 1.0g of sample was evenly spread in a petri dish and placed in the test chamber. The ozone concentration in the chamber was measured every 5 minutes using an ozone detector. The experimental results showed that the ozone inhibitor of this invention exhibited the best ozone removal performance, almost completely removing ozone within 30 minutes. Its efficiency was significantly higher than that of mesoporous MnO2 catalysts alone and traditional activated carbon adsorbents, demonstrating the synergistic effect of catalytic decomposition and chemical removal.

[0054] Compared with the prior art, the present invention has the following significant advantages:

[0055] Synergistic effect and ultra-high efficiency: This invention organically combines the catalytic decomposition of MnO2 with the chemical scavenging effect of thiourea derivatives. When ozone molecules come into contact with the inhibitor surface, a portion is rapidly catalytically decomposed into oxygen by the active sites on the MnO2 surface, while the other portion is preferentially consumed by N,N′-dipiperidinylthiourea. This "catalytic + chemical" dual-channel mode greatly improves the ozone removal rate and total capacity, and its overall efficiency is far higher than that of using either component alone.

[0056] Optimized structure and stable performance: The mesoporous MnO2 prepared by optimizing the sol-gel method and precisely controlling the calcination temperature (e.g., 400℃) has a stable crystal structure, high specific surface area and well-developed pore system, which ensures its long-term catalytic activity and structural stability.

[0057] Dual Functions, Wide Applications: The composite ozone inhibitor of this invention can serve not only as a highly efficient air purification material but also as a high-performance rubber ozone inhibitor. In rubber, it not only forms a protective film on the surface or reacts with ozone like traditional ozone inhibitors, but its catalytic core can also continuously decompose ozone that has penetrated into the material, forming a three-dimensional protective system of "surface interception + internal removal," significantly extending the material's service life, especially under dynamic stress conditions.

[0058] Green and environmentally friendly with low pollution: The main reaction product is oxygen. Compared with traditional p-phenylenediamine-based anti-ozone agents, the chemical scavenger N,N′-dipiperidinylthiourea has less color pollution and is more environmentally friendly.

[0059] The present invention and its embodiments have been described above. This description is not restrictive, and the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and, without departing from the spirit of the invention, design similar structures and embodiments without creative effort, all such designs should fall within the protection scope of the present invention.

Claims

1. A method for preparing an ozone inhibitor, characterized in that: Includes the following steps: Step 1: Raw material preparation: Select a manganese dioxide catalyst core with a mesoporous structure, accounting for 80%-98% of the total weight, and select a thiourea-based chemical scavenger loaded on the catalyst core, accounting for 2%-20% of the total weight. Step 2: Mixing and dissolving: Add the thiourea chemical cleaner and the manganese dioxide catalyst core to an appropriate amount of organic solvent to dissolve them, so as to achieve the composite of the thiourea chemical cleaner and the manganese dioxide catalyst core. Disperse them in an ultrasonic cleaner to make them evenly mixed. Step 3: Organic solvent removal: Transfer the well-mixed solution to a rotary evaporator and remove the organic solvent by vacuum stirring under water bath to obtain solid powder; Step 4: Vacuum drying: The obtained solid powder is dried under a vacuum to obtain the ozone inhibitor product of the present invention.

2. The preparation method of an ozone inhibitor according to claim 1, characterized in that: The BET specific surface area of ​​the manganese dioxide catalytic core in step one is 140 m². 2 / g-180m 2 / g.

3. The preparation method of an ozone inhibitor according to claim 1, characterized in that: The preparation of the mesoporous manganese dioxide catalytic core in step one adopts the sol-gel method, and the specific steps are as follows: a) Dissolve manganese acetate tetrahydrate in deionized water to form a precursor solution; b) Add citric acid to the precursor solution and stir in a water bath at a certain temperature to form a homogeneous sol; c) Slowly add ammonia water dropwise while stirring to adjust the pH value of the solution, and continue stirring to age and form a gel for 10-12 hours; d) Wash the solid alternately with deionized water and anhydrous ethanol until neutral, centrifuge, and dry the solid at 90-120℃; e) The dried solid is heated and calcined in an air atmosphere, and after being calcined at a constant temperature for a period of time, mesoporous manganese dioxide powder with high catalytic activity is obtained.

4. The preparation method of an ozone inhibitor according to claim 3, characterized in that: In step b, the water bath stirring temperature is 60℃-80℃; in step c, the solution pH is adjusted to 8-10; in step e, the calcination temperature is 380℃-420℃; and the constant temperature calcination time is 3-5 hours.

5. The preparation method of an ozone inhibitor according to claim 1, characterized in that: The thiourea chemical scavenger in step one is N,N′-dipiperidinylthiourea.

6. The preparation method of an ozone inhibitor according to claim 1, characterized in that: The preparation of the thiourea chemical scavenger in step one is carried out using a microwave-assisted method, and the specific steps are as follows: a) Thiourea and hexahydropyridine are mixed in anhydrous ethanol solvent at a molar ratio of 1:2.2; b) Place the mixed solution in a microwave reactor for irradiation reaction; c) After the reaction is complete, the mixture is cooled, filtered, washed and dried to obtain a high-purity white powder of N,N′-dipiperidinylthiourea.

7. The preparation method of an ozone inhibitor according to claim 6, characterized in that: In step b, the microwave power in the microwave reactor is 260W-320W, the temperature is 50℃-60℃, and the radiation reaction time is 8-10min.

8. The preparation method of an ozone inhibitor according to claim 1, characterized in that: In step two, the organic solvent is one of toluene, ethanol, etc., which can be used to ensure that the thiourea chemical scavenger and manganese dioxide catalyst core are fully dissolved without affecting the performance of the ozone inhibitor.

9. The preparation method of an ozone inhibitor according to claim 1, characterized in that: The dispersion time in the ultrasonic cleaner in step two is 20-40 minutes, the water bath temperature in step three is 45℃-70℃, and the vacuum drying temperature in step four is 70℃-85℃ for 3.5-4.5 hours.