A process for preparing granular antioxidant 4020

Abstract

The present invention relates to a new process for preparing granular antioxidant 4020. The technical solution includes the following processes: adding RT base and methyl isobutyl ketone into a reaction kettle according to a molar ratio of 1:3, adding a catalyst, introducing hydrogen, maintaining pressure for reaction to obtain a hydrogenation reaction solution; then filtering, recycling and reusing the catalyst, evaporating the volume through a wiped film evaporator to pour out the residue, standing, and under the action of the centrifugal force generated by a high-speed rotating nozzle and the convection formed under the action of an induced draft fan and a forced draft fan, the dropping time of the material will be increased, and it will be cooled to reach the freezing point; the solidified particles are screened by a linear screening machine to form the solid particle antioxidant 4020. The beneficial effects are as follows: in the granulation process of the present invention, the rotation radius of the nozzle and the discharging speed of the nozzle can be changed to avoid excessive production of antioxidant 4020 and reduce costs; the particle shape of antioxidant 4020 can be changed to make it more beautiful and standard, and the recycling cost can be reduced.

Description

Technical Field

[0001] The present invention relates to a production device and method for granular anti-aging agents, and particularly to a process for preparing granular anti-aging agent 4020. Background Art

[0002] Anti-aging agent 4020, also known as anti-aging agent DMBPPD, belongs to the rubber anti-aging agent of the p-phenylenediamine type. The pure product of this product is a white powder, which oxidizes into a brown solid when exposed to air. In addition to having good antioxidant performance, it also has the functions of anti-ozone, anti-flexure cracking, and inhibiting harmful metals such as copper and manganese. Its performance is similar to that of anti-aging agent 4010NA, but its toxicity and skin irritation are smaller than those of 4010NA, and its dissolution characteristics in water are also better than those of 4010NA.

[0003] In the future, rubber anti-aging agent 4020 will be more applied in the tires of the automotive industry.

[0004] However, the problems existing in the preparation of anti-aging agent 4020 at present are: the domestic production process is complex, the production device supporting is insufficient, the product yield and qualification rate are low, and the number of catalyst recycling times is small.

[0005] In addition, the problems existing in the granulation technology of the existing anti-aging agent 4020 are: the process is complex. From 4020 through cooling, then to pre-crystallization, granulator, dropping machine, steel belt, sieve plate, weighing, and packaging, this process flow is complex, the process is cumbersome, the process occupies more land, the temperature control is relatively strict, the process parameters are difficult to control, the pre-crystallizer is fouled, and on the granulation device, the liquid droplets generated by the dropping machine are of different sizes. After passing through the steel belt, some are not formed standardly, with a "bean paste type" shape, and some products do not meet the production standards and need to be re-melted and recycled. The finished product rate is low, a large amount of dust is generated, it is easy to cause dust hazards, and the dust and unqualified 4020 recovery costs are high. Summary of the Invention

[0006] The purpose of the present invention is to address the above-mentioned defects existing in the prior art, and provide a process for preparing granular anti-aging agent 4020. After improvement, the present invention will achieve a yield and purity of 99%, increase the number of catalyst recycling times, and reduce the manufacturing cost; in addition, the granulation nozzle is transformed, cold air is used, and the liquid droplets are cooled and formed by the natural dropping and cooling method in a high tower, changing from the original bean paste type to a granular structure, making it more beautiful and standard.

[0007] A process for preparing granular anti-aging agent 4020 mentioned in the present invention, its technical solution is: including the following processes:

[0008] First, the catalyst is introduced and pre-treated by heating with hydrogen.

[0009] II. Add RT base and methyl isobutyl ketone into the reaction kettle at a molar ratio of 1:3, add a catalyst pretreated by heating with a mass percentage of 25%, introduce hydrogen, maintain the pressure, with the reaction temperature at 100 - 130 °C and the reaction time at 3 - 5 h to obtain a hydrogenation reaction solution;

[0010] III. Filter the obtained hydrogenation reaction solution, recycle the catalyst, evaporate the solvent through a wiped film evaporator to pour out the residue, let it stand, and then granulate the particles;

[0011] IV. The granulation process is as follows: Utilize the centrifugal force generated by a high - speed rotating nozzle. Under the action of an induced draft fan and a forced draft fan to form a convection, it will increase the dripping time of the material, cool it down to reach the freezing point of 45 °C; The solidified particles are screened by a linear screening machine, and the qualified products enter the silo to form the antioxidant 4020 in solid particle form.

[0012] Preferably, in step II, the maintained pressure of hydrogen is 3.8 MPa.

[0013] Preferably, the reaction kettle is equipped with stirring, and the stirring rate is 50 - 100 revolutions per minute.

[0014] Preferably, in step II, the reaction temperature is 110 - 120 °C.

[0015] Preferably, in step III, the number of times the catalyst is recycled and reused is 75 - 85 times.

[0016] Preferably, the catalyst used is a copper - based catalyst.

[0017] The device for implementing the process for preparing granular antioxidant 4020 mentioned in the present invention has the following technical solution: It includes a base storage tank (1), a methyl ketone storage tank (2), a hydrogen storage tank (3), a reaction kettle (4), a first separator (5), a first condenser (6), a second condenser (7), a second separator (8), a wiped film evaporator (9), and a 4020 storage tank (10). The base storage tank (1), the methyl ketone storage tank (2), and the hydrogen storage tank (3) are respectively connected to the reaction kettle (4) through pipelines. The output end of the reaction kettle (4) is connected to the first separator (5) through a pipeline. The bottom of the first separator (5) is connected to the inlet of the wiped film evaporator (9) through a pipeline. The lower outlet of the wiped film evaporator (9) is connected to the 4020 storage tank (10) through a pipeline and then sent to a granulation device (11) for granulation; The top of the first separator (5) is connected to the second separator (8) through the first condenser (6) and the second condenser (7). The upper outlet is connected to a hydrogen recovery pipe, and the lower outlet is connected to a solvent recovery pipe.

[0018] Preferably, the granulation device (11) includes a finished product transfer pump (11.2), a rotary atomizer (11.3), a gearbox (11.4), a motor (11.5), an induced draft fan (11.6), a granulation tower (11.7), a condenser (11.9), a forced draft fan (11.10), an air volume regulating valve (11.11), and a linear screening machine (11.12). A rotary atomizer (11.3) is installed in the upper part of the inner cavity of the granulation tower (11.7). The rotary atomizer (11.3) is connected to the output end of the gearbox (11.4), and the output end of the motor (11.5) is connected to the gearbox (11.4). The upper part of the rotary atomizer (11.3) is connected to the outlet of the 4020 storage tank (10) through a pipeline and the finished product transfer pump (11.2). The upper middle part of the granulation tower (11.7) is connected to the induced draft fan (11.6). The lower side of the granulation tower (11.7) is connected to the forced draft fan (11.10), and the outside of the forced draft fan (11.10) is connected to the condenser (11.9). A linear screening machine (11.12) is provided at the bottom of the granulation tower (11.7).

[0019] Preferably, a storage bin (11.13) is provided below the linear screening machine (11.12), and a quantitative weighing scale (11.14) is provided at the outlet of the storage bin (11.13).

[0020] Preferably, the left end of the condenser (11.9) is connected to an exhaust fan (11.8). Both ends of the condenser (11.9) are connected in parallel with a secondary pipeline, and a secondary pipeline gate valve (11.1) is provided on the secondary pipeline.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses RT base and methyl ketone as raw materials, and the catalyst is subjected to heat treatment with hydrogen. The product manufacturing process is a domestic initiative. The development of this product provides a new process for rubber antioxidants, improving the yield and quality of rubber antioxidants. After improvement, the present invention will achieve a yield and purity of 99%, increasing the number of catalyst reuse times and reducing the manufacturing cost.

[0022] In addition, in the granulation process of the present invention, the rotation radius of the nozzle can be changed according to the frequency of the rotating nozzle motor, and the discharging speed of the nozzle can be changed according to production requirements, so as to avoid excessive production of antioxidant 4020 and reduce the company's storage cost; the shape of the antioxidant 4020 particles can be changed to make them more beautiful and standard, reducing the recycling cost; in the original granulation device, the sizes of the particles dropped by the dropping machine are different. After being cooled by the steel belt, their shapes are "douban-shaped", and some products do not meet the production standards and need to be remelted and recycled. The present invention can convert the "douban-shaped" particles into "granular" particles, which can not only reduce the recycling cost, but also make the produced products "granular", with beautiful finished products, less recycling, reduced production costs, less generated dust, and easy recycling; a large amount of dust is generated by the vibration of the sieve plate in the original granulator, which not only poses a great safety hazard to production, but also has a great impact on the physical and mental health of employees. The invention of this new process can reduce the generation of dust, facilitate recycling, reduce the corresponding safety hazards, and ensure the physical and mental health of employees. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the preparation process of the present invention;

[0024] Figure 2 is a graph showing the influence of the ratio of RT base to methyl ketone on the reaction conversion rate;

[0025] Figure 3 is a schematic diagram of the structure of the granulation device;

[0026] In the above figure: RT base storage tank 1, methyl ketone storage tank 2, hydrogen storage tank 3, reaction kettle 4, first separator 5, first condenser 6, second condenser 7, second separator 8, wiped film evaporator 9, 4020 storage tank 10, bypass gate valve 11.1, finished product transfer pump 11.2, rotating nozzle 11.3, gearbox 11.4, motor 11.5, induced draft fan 11.6, granulation tower 11.7, exhaust fan 11.8, condenser 11.9, air supply fan 11.10, air volume regulating valve 11.11, linear screening machine 11.12, storage bin 11.13, quantitative weighing scale 11.14. DETAILED DESCRIPTION OF THE INVENTION

[0027] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0028] Example 1, referring to Figure 1, the device of the present invention for implementing the process of preparing granular antioxidant 4020 includes a p-aminodiphenylamine storage tank 1, a methyl ethyl ketone storage tank 2, a hydrogen storage tank 3, a reaction kettle 4, a first separator 5, a first condenser 6, a second condenser 7, a second separator 8, a thin-film evaporator 9, and a 4020 storage tank 10. The p-aminodiphenylamine storage tank 1, the methyl ethyl ketone storage tank 2, and the hydrogen storage tank 3 are respectively connected to the reaction kettle 4 through pipelines. The output end of the reaction kettle 4 is connected to the first separator 5 through a pipeline. The bottom of the first separator 5 is connected to the inlet of the thin-film evaporator 9 through a pipeline. The lower outlet of the thin-film evaporator 9 is connected to the 4020 storage tank 10 through a pipeline and then sent to a granulation device 11 for granulation. The top of the first separator 5 is connected to the second separator 8 through the first condenser 6 and the second condenser 7. The upper outlet is connected to a hydrogen recovery pipe, and the lower outlet is connected to a solvent recovery pipe.

[0029] Refer to Figure 3 , the granulation device 11 mentioned in the present invention includes a finished product transfer pump 11.2, a rotary atomizer 11.3, a gearbox 11.4, a motor 11.5, an induced draft fan 11.6, a granulation tower 11.7, a condenser 11.9, a forced draft fan 11.10, an air volume regulating valve 11.11, and a linear screening machine 11.12. The rotary atomizer 11.3 is installed in the upper part of the inner cavity of the granulation tower 11.7. The rotary atomizer 11.3 is connected to the output end of the gearbox 11.4, and the output end of the motor 11.5 is connected to the gearbox 11.4. The upper part of the rotary atomizer 11.3 is connected to the outlet of the 4020 storage tank 10 through a pipeline and the finished product transfer pump 11.2. The upper middle part of the granulation tower 11.7 is connected to the induced draft fan 11.6. The lower side of the granulation tower 11.7 is connected to the forced draft fan 11.10, and the outside of the forced draft fan 11.10 is connected to the condenser 11.9. The bottom of the granulation tower 11.7 is provided with a linear screening machine 11.12.

[0030] In addition, a storage bin 11.13 is provided below the linear screening machine 11.12, and a quantitative weighing scale 11.14 is provided at the outlet of the storage bin 11.13.

[0031] The left end of the above-mentioned condenser 11.9 is connected to an exhaust fan 11.8. Both ends of the condenser 11.9 are connected in parallel with a secondary pipeline, and a secondary pipeline gate valve 11.1 is provided on the secondary pipeline. Among them, the function of the condenser is that the air volume regulating valve has the advantage that it can well control the air temperature and air speed. In summer, when the temperature is relatively high, the air temperature can be reduced by the condenser to improve the cooling efficiency, which can be adjusted according to requirements. There is a secondary pipeline connection between the exhaust fan and the induced draft fan. The number of fans to be turned on can be selected according to actual production. When the demand is large, they can be turned on simultaneously. When the demand is small, one fan can be selected to be turned on. This not only ensures the production demand but also saves production costs.

[0032] A process for preparing granular antioxidant 4020 mentioned in the present invention includes the following processes:

[0033] 1. Hydrogenation reaction

[0034] 184 g of RT base and 300 g of methyl ketone were placed in an autoclave, and 8.4 g of copper-based catalyst 2 was added. The copper-based catalyst 2 was first heated and pre-treated by passing hydrogen, and then replaced with nitrogen and hydrogen. The pressure was adjusted to 3.0 MPa, and stirring was started. The temperature was raised to 130° C. The reaction was started by passing hydrogen and the reaction was carried out under constant temperature and pressure conditions for 3 hours. After the reaction was completed, the temperature was lowered, the pressure was released, the autoclave was disassembled, and the materials were discharged to obtain a hydrogenation reaction liquid containing the catalyst.

[0035] 2. Post-processing

[0036] The hydrogenation reaction liquid was filtered using a saffron funnel, and the copper-based catalyst 1 was recovered and reused. The reaction oil layer was placed in a four-necked flask, and after addition, the temperature was raised to 120°C for atmospheric distillation to begin extraction. Oil-water separation began, and the distillate was steadily extracted until the air temperature dropped slightly. The liquid temperature was then raised to 180°C, and then vacuum distillation was switched. When the vacuum reached a certain temperature, the product was extracted, and the residue in the high-boiling still was the product. The viscous liquid was cooled and poured into a stainless steel pan, where it completely solidified into a solid block at room temperature for approximately 24 hours. The separated methyl ketone was reused in the hydrogenation reaction, and impurities were removed from the system in the vacuum distillation fraction. The conversion of RT base was calculated to be 182.34 / 184 = 99.1%. The product purity was 98.28%. The above experimental steps were repeated, varying the ratio of RT base to methyl ketone to obtain different conversion rates.

[0037] 3. Granulation process

[0038] The finished product delivery pump will deliver the antioxidant 4020 in the 4020 storage tank to the rotating nozzle. The rotating nozzle rotates at high speed driven by the gearbox and motor. The centrifugal force and pressure generated by the rotating nozzle will throw the antioxidant 4020 out of the rotating nozzle. The rotation radius can be controlled by the motor. By changing the motor frequency, the centrifugal radius can be changed. The injection speed is controlled by the gearbox. Ventilation is required before the granulation begins. At the same time, the induced draft fan and the supply fan are turned on to form a certain amount of air convection in the tower.

[0039] At the beginning of granulation, the high-speed rotation of the rotating nozzle generates centrifugal force to throw out the antioxidant 4020. Under the action of the induced draft fan and the forced draft fan, the convection is formed, which increases the dripping time of the material and cools it down to the solidification point of 45°C. The solidified particles are screened by a linear screening machine, and the qualified products are put into the silo, quantitatively weighed and packaged.

[0040] It should be noted that:

[0041] The granulation process of the present invention mainly focuses on modifying the particle shape of antioxidant 4020. Utilizing the centrifugal force generated by a high-speed rotating nozzle, the actual trajectory of the antioxidant 4020 jet is the result of the combined effect in the horizontal and vertical directions. The movement trajectory of the antioxidant 4020 liquid is equivalent to a curved jet formed by the nozzle holes, and multiple jet liquid columns are ejected from the nozzle holes on the surface of the nozzle. Along with the movement of the jet in the horizontal and vertical directions, fluctuations are observed to propagate on the surface of the liquid column. During the movement process, when the tensile force borne by the liquid is greater than the self-breaking force, the liquid column will break to form main droplets and satellite droplets. The droplets fall in the air, are cooled and solidified due to the air convection effect, and finally form solid particles.

[0042] The experimental data of the present invention are shown in Table 1.1 below

[0043] Table 1.1 Influence of the ratio of RT base to methyl ketone on the reaction conversion rate

[0044]

[0045] Refer to Figure 2 , the influence curve graph of the ratio of RT base to methyl ketone on the reaction conversion rate;

[0046] Analysis: According to the experimental results, it is found that the optimal ratio of RT base to methyl ketone is 1:3. This not only saves production raw materials but also reduces the reaction load.

[0047] After determining the optimal ratio of 1:3, experiments were conducted on copper-based catalysts 1, 2, and 3 respectively. The NZF-type copper-based catalysts, which are three models of Nanjing Zunlong New Materials Technology Co., Ltd., were used. The experimental data are shown in Table 1.2 below

[0048] Table 1.2 Influence of different series of catalysts on the reaction

[0049]

[0050] Analysis: As can be seen from the above, choosing copper-based catalyst 2 results in the highest conversion rate and the best selectivity in the reaction process.

[0051] Example 2,

[0052] A process for preparing granular antioxidant 4020 mentioned in the present invention specifically includes the following steps:

[0053] Add 74 g of base and 150 g of methyl ketone, and add 8 g of copper-based catalyst 2. The temperature is controlled at 100 °C, so the conversion rate and selectivity of the reaction under different pressures are investigated. The results are shown in Table 1.3 below

[0054] Table 1.3 Influence of reaction pressure on the reaction

[0055]

[0056] Analysis: Analyze the experimental data. After the pressure is greater than 2 MPa, the conversion rate can be about 99%, but the selectivity is relatively low, and the content of 4020 also decreases accordingly. Therefore, the reaction pressure for adding hydrogen is preferably 3.8 MPa.

[0057] Example 3

[0058] A process for preparing granular antioxidant 4020 mentioned in the present invention specifically includes the following process: Determine the reaction pressure to be 3.8 MPa. Between different reaction temperatures, add 74 g of p-phenylenediamine and 150 g of methyl ethyl ketone, and add 8 g of copper-based catalyst 2. The reaction time is 3 h to determine the influence of different temperatures on the reaction. The results are shown in Table 1.4

[0059] Table 1.4 Influence of Different Reaction Temperatures on the Reaction

[0060]

[0061] Analysis: In the range of 110 - 140 °C, the conversion rate of p-phenylenediamine reaction is relatively high, all reaching 99%. When the temperature rises to 140 °C, the selectivity shows a downward trend. Especially when the temperature reaches 130 - 140 °C, the impurity peaks of 4020 increase significantly, directly affecting the product quality. Therefore, the temperature is determined to be between 110 - 130 °C.

[0062] Example 4

[0063] A process for preparing granular antioxidant 4020 mentioned in the present invention specifically includes the following process: At 3.8 MPa and between 110 - 130 °C, with a reaction time of 3 h, investigate the life and stability of the catalyst. Add 74 g of p-phenylenediamine and 150 g of methyl ethyl ketone, and add 8 g of copper-based catalyst 2. The experimental data obtained are shown in Table 1.5

[0064] Table 1.5 Influence of Catalyst Recycling on the Reaction

[0065]

[0066] Analysis: Under the conditions of 3.8 MPa, between 110 - 130 °C, and a reaction time of 3 h, it is found that except for the first batch with relatively poor reaction effect, the reaction effects from the 10th to the 20th recycling are very good, and the activity and selectivity of the catalyst do not decrease during the recycling process. When continuing to recycle to the 21st batch, the conversion rate is only 98%. By extending the reaction time, the conversion rate reaches 99% again. This indicates that the activity of the catalyst begins to decline. Therefore, the catalyst is pretreated by hydrogenation.

[0067] Table 1.6 Influence of Catalyst Pretreatment on the Reaction

[0068]

[0069] Analysis: Hydrogen reduction pretreatment can well solve the problems of poor activity and selectivity of the catalyst in its first use, and can also increase the recycling times of the catalyst, saving production costs. By optimizing the pretreatment time, it is found that the activity of the new catalyst can be restored after 1 hour of pretreatment.

[0070] As described above, only some of the preferred embodiments of the present invention are given. Any person skilled in the art may modify the above-described technical solution or modify it into an equivalent technical solution. Therefore, any corresponding simple modification or equivalent transformation made according to the technical solution of the present invention falls within the scope of protection required by the present invention.

Claims

1. A process for preparing granular antioxidant 4020, characterized in that: It includes the following processes:

1. First, the catalyst is pre-treated by heating with hydrogen.

2. RT base and methyl isobutyl ketone are added to the reaction kettle at a molar ratio of 1:3, and 25% by mass of the catalyst after heating pre-treatment is added. Hydrogen is introduced, the pressure is maintained, the reaction temperature is 100 - 130 °C, and the reaction time is 3 - 5 h to obtain a hydrogenation reaction solution.

3. The obtained hydrogenation reaction solution is filtered, the catalyst is recovered and reused, the solvent is evaporated by a wiped film evaporator, the residue is poured out, left standing, and then granulated.

4. The granulation process is as follows: Using the centrifugal force generated by a high-speed rotating nozzle, under the action of an induced draft fan and a forced draft fan to form a convection, the dropping time of the material will be increased, and it will be cooled to reach the freezing point of 45 °C; the solidified particles are screened by a linear screening machine, and the qualified products enter the silo to form the antioxidant 4020 in solid particle form. The catalyst used is a copper-based catalyst. The device adopted in the process includes a base storage tank (1), a methyl ketone storage tank (2), a hydrogen storage tank (3), a reaction kettle (4), a first separator (5), a first condenser (6), a second condenser (7), a second separator (8), a wiped film evaporator (9), and a 4020 storage tank (10). The base storage tank (1), the methyl ketone storage tank (2), and the hydrogen storage tank (3) are respectively connected to the reaction kettle (4) through pipelines. The output end of the reaction kettle (4) is connected to the first separator (5) through a pipeline. The bottom of the first separator (5) is connected to the inlet of the wiped film evaporator (9) through a pipeline. The lower end outlet of the wiped film evaporator (9) is connected to the 4020 storage tank (10) through a pipeline and then sent to a granulation device (11) for granulation; the top of the first separator (5) is connected to the second separator (8) through the first condenser (6) and the second condenser (7). The upper end outlet is connected to a hydrogen recovery pipe, and the lower end outlet is connected to a solvent recovery pipe. The granulation device (11) includes a finished product transfer pump (11.2), a rotating nozzle (11.3), a gearbox (11.4), a motor (11.5), an induced draft fan (11.6), a granulation tower (11.7), a condenser (11.9), a forced draft fan (11.10), an air volume regulating valve (11.11), and a linear screening machine (11.12). The rotating nozzle (11.3) is installed in the upper part of the inner cavity of the granulation tower (11.7). The rotating nozzle (11.3) is connected to the output end of the gearbox (11.4), and the output end of the motor (11.5) is connected to the gearbox (11.4); the upper part of the rotating nozzle (11.3) is connected to the outlet of the 4020 storage tank (10) through a pipeline and the finished product transfer pump (11.2); the upper middle part of the granulation tower (11.7) is connected to the induced draft fan (11.6); the lower side of the granulation tower (11.7) is connected to the forced draft fan (11.10), and the outside of the forced draft fan (11.10) is connected to the condenser (11.9); the bottom of the granulation tower (11.7) is provided with a linear screening machine (11.12). Below the linear vibrating screen (11, 12), there is a storage bin (11, 13), and a quantitative weighing scale (11, 14) is provided at the outlet of the storage bin (11, 13). The left end of the condenser (11, 9) is connected to an exhaust fan (11, 8). Both ends of the condenser (11, 9) are connected in parallel with a secondary pipeline, and a secondary pipeline gate valve (11, 1) is provided on the secondary pipeline.

2. The process for preparing granular antioxidant 4020 according to claim 1, characterized in that: In step two, the holding pressure of hydrogen is 3.8 MPa.

3. The process for preparing granular antioxidant 4020 according to claim 2, characterized in that: The reaction kettle is equipped with stirring, and the stirring rate is 50 - 100 revolutions per minute.

4. The process for preparing granular antioxidant 4020 according to claim 3, characterized in that: In step two, the reaction temperature is 110 - 120 °C.

5. The process for preparing granular antioxidant 4020 according to claim 4, characterized in that: In step three, the number of times the catalyst is recycled and reused is 75 - 85 times.

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