Butylthiourea derivatives and preparation methods and applications thereof
By developing n-butylthiourea derivatives, the problem of converting 6PPD into toxic substances in the prior art was solved, and an anti-ozone agent that replaces 6PPD in tire rubber was realized, with excellent anti-ozone properties and environmental friendliness.
Patent Information
- Application Number
- CN202411665773.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-04-01
AI Technical Summary
The antioxidant 6PPD used in existing tires is converted into a toxic substance 6PPDQ after reacting with ozone and oxygen, resulting in environmental pollution and human health risks, and its alternatives are difficult to replace effectively in rubber.
A n-butylthiourea derivative was developed to prepare a new material with excellent ozone resistance and environmental friendliness by reacting with a modifier and an acid binding agent to replace 6PPD as an anti-ozone agent in tire rubber.
This n-butylthiourea derivative not only maintains excellent anti-ozone activity, but also reduces the impact on the scorching time of the rubber, and has little harm to water, soil, etc., and is environmentally friendly. It can effectively replace 6PPD as a tire rubber protective agent.
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Figure CN119735534A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of rubber protective agents, and more specifically, to an n-butylthiourea derivative and a preparation method and application thereof. Background Art
[0002] 6PPD, the full name of which is N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, is an antioxidant commonly used in tires. The main function of 6PPD is to prevent cracking and thermal-oxidative degradation of tire rubber, thereby extending the service life of the tire. However, after reacting with ozone and oxygen, 6PPD will be converted into 6PPD quinone (i.e. 6PPDQ), a toxic substance that has been found in road runoff and receiving water systems. 6PPDQ is highly toxic to aquatic organisms, especially to coho salmon, with a very low median lethal concentration of less than 0.1ng / mL. Studies have shown that the amount of 6PPD, the precursor of 6PPDQ, added to tires generally accounts for 0.4-2% of the total weight of the tire, and the environmental concentration and annual intake of 6PPDQ indicate that long-term exposure to this type of pollutant may pose a great risk to human health.
[0003] 6PPD can undergo rapid photolysis under simulated sunlight to generate a variety of products including 6PPDQ. 6PPDQ is widely distributed in the environment and has been detected not only in water bodies but also in dust, air particles, soil and sediments, showing its global pollution trend. The toxicity of 6PPDQ is not limited to aquatic animals, but is also bioavailable to mammals. Acute exposure to 6PPDQ can be fatal to some organisms.
[0004] In summary, 6PPD is an important tire antioxidant, but its conversion product 6PPDQ poses a potential risk to the environment and human health. Therefore, it is imperative to reduce or stop adding 6PPD to tire rubber and study environmentally friendly antiozonants that can replace 6PPD in rubber. Summary of the invention
[0005] In order to solve the environmental pollution problem caused by using 6PPD as a tire antioxidant in the prior art, the present application provides an n-butylthiourea derivative and a preparation method and application thereof.
[0006] In a first aspect, the present application provides an n-butylthiourea derivative, the structural formula of which is as follows:
[0007]
[0008] Wherein, R1, R2, and R3 are each independently H, an aromatic group, a cycloalkyl group, or an alkyl group having 4 to 8 carbon atoms;
[0009] The aromatic structural formula is:
[0010]
[0011] The cycloalkyl structural formula is:
[0012]
[0013] The alkyl structural formula:
[0014] -C n H2 n+1 ,
[0015] R4 and R5 are each independently an aromatic group, a cycloalkyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group, and n is an integer of 4 to 8.
[0016] In a second aspect, the present invention provides a method for preparing an n-butylthiourea derivative, comprising placing n-butylthiourea and a modifier in a reactor, and then adding a first organic solvent into the reactor to dissolve the n-butylthiourea and the modifier; dissolving an acid-binding agent in a second organic solvent, and dripping the solution into the reactor while stirring, and heating the reactor to react, thereby obtaining an n-butylthiourea derivative;
[0017] The structural formula of n-butylthiourea is as shown in Formula II:
[0018]
[0019] The modifier is one or more of aromatic hydrocarbons, cycloalkanes or alkanes, wherein the structural formula of the aromatic hydrocarbon is as shown in Formula III:
[0020]
[0021] The structural formula of cycloalkane is as shown in Formula IV:
[0022]
[0023] The structural formula of the alkane is as shown in Formula V:
[0024]
[0025] R4 and R5 are each independently H, an aromatic group, a cycloalkyl group or an alkyl group having 1 to 6 carbon atoms, n is an integer of 4 to 8, and R6, R7, and R8 are each independently Br, I or OH.
[0026] Furthermore, the acid binding agent is one or more of triethylamine, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, potassium bicarbonate, and potassium hydroxide.
[0027] Furthermore, the second organic solvent is the same as the first organic solvent, and the first organic solvent is one or more of dimethylformamide, dimethyl sulfoxide, ethanol, methanol, acetone, and chloroform.
[0028] Furthermore, the molar ratio of n-butylthiourea to the modifier is 1:2-5.
[0029] Furthermore, the reaction temperature is 50-120° C., and the reaction time is 4-20 h.
[0030] It should be noted that n-butylthiourea contains primary and secondary amines and has strong alkalinity, which can promote sulfur vulcanization, shorten the rubber scorch time, and reduce the safety of rubber processing. If other substituents are used to replace the H connected to N, its alkalinity can be reduced and the impact on the rubber scorch time can be reduced. The C=S bond of n-butylthiourea has a strong reducing property and is easy to react with ozone to generate oxidized n-butylthiourea (including formula VI, VII, VIII). If a modifier with an electron-donating capacity greater than that of hydrogen is used to connect to N, the reducing property of the C=S bond on the n-butylthiourea derivative will be enhanced, and its reactivity with ozone will be improved.
[0031] The structural formula of oxidized n-butylthiourea is as shown in Formula VI:
[0032]
[0033] The structural formula of oxidized n-butylthiourea is as shown in Formula VII:
[0034]
[0035] The structural formula of oxidized n-butylthiourea is as shown in Formula VIII:
[0036]
[0037] In a third aspect, the present invention provides use of n-butylthiourea derivatives in tire rubber.
[0038] Furthermore, n-butylthiourea derivatives are used as protective agents for tire rubber.
[0039] Furthermore, the n-butylthiourea derivative can be used alone as a tire rubber protective agent, or can be used together with other tire rubber protective agents.
[0040] Furthermore, the n-butylthiourea derivatives are used as antiozonants for natural rubber, synthetic isoprene rubber, butadiene rubber, styrene-butadiene rubber, and halogenated butyl rubber.
[0041] It should be noted that n-butyl thiourea has good anti-ozone performance to natural rubber, cis-1,4-butadiene rubber, styrene-butadiene rubber, etc., and its anti-ozone activity is equal to that of rubber protective agent 4010NA. In addition, n-butyl thiourea is less harmful to water bodies, soil, etc., has environmental friendliness, and can be used as a green environmentally friendly protective agent for tire rubber. However, n-butyl thiourea can promote rubber vulcanization, shorten the scorch time, reduce rubber processing safety, and affect rubber performance. Therefore, the present application prepares a derivative of n-butyl thiourea by modifying n-butyl thiourea, reduces its impact on the scorch time, and maintains excellent anti-ozone activity, and can replace the commonly used anti-ozonant 6PPD of rubber as a rubber protective agent.
[0042] In summary, this application has the following beneficial effects:
[0043] n-Butylthiourea has excellent anti-ozone performance, but it will greatly shorten the scorch time of rubber and affect the safety of rubber processing. The present invention modifies n-butylthiourea to prepare n-butylthiourea derivatives, which have little effect on the scorch time of rubber, have excellent anti-ozone activity and processing performance, have little harm to water bodies, soil, etc., are environmentally friendly, can be used as a green and environmentally friendly protective agent for tire rubber, and can replace 6PPD as a tire rubber protective agent. BRIEF DESCRIPTION OF THE DRAWINGS
[0044] Figure 1 It is a comparison chart of the normalized scorch time of the rubber of Examples 1-2 and Comparative Examples 1-2 of the present application;
[0045] Figure 2 It is a comparison chart of the rubber of Example 1-2 of the present application and Comparative Example 1-2 after ozone aging. DETAILED DESCRIPTION
[0046] The present application is further described in detail with reference to the following examples. It should be noted that if no specific conditions are specified in the following examples, the conventional conditions or the conditions recommended by the manufacturer are followed, and the raw materials used in the following examples can be obtained from common commercial sources unless otherwise specified.
[0047] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.
[0048] In this application, "first aspect", "second aspect", "third aspect", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.
[0049] In this application, "optionally", "optional", and "optional" mean optional or dispensable, that is, any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.
[0050] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.
[0051] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.
[0052] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used in this application and in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this application includes any and all combinations of one or more related listed items. The term "multiple" in this application means at least two, such as two, three, etc., unless otherwise clearly and specifically limited.
[0053] The raw materials used in this application are all commercially available products.
[0054] Example 1
[0055] The preparation method of n-butylthiourea derivative 1 is as follows: 2.64g of n-butylthiourea and 11.53g of bromoethylbenzene are added to a 500ml three-necked flask, and then 100ml of ethanol is added to the three-necked flask to completely dissolve the n-butylthiourea and bromoethylbenzene. An ethanol solution containing 6.37g of triethylamine is added dropwise to the three-necked flask while stirring. After the addition is complete, the temperature is raised and refluxed for reaction for 10h. After the reaction is completed, the precipitate is filtered to remove the solvent and excess reactants in the reaction solution are removed by a rotary evaporator, and then the reaction solution is recrystallized from ethanol-water for 2-3 times and dried to obtain the thiourea derivative 1.
[0056] The n-butylthiourea derivative 1 was used as a protective agent for tire rubber instead of 6PPD.
[0057] The tire rubber composition includes the following components: 100 parts of natural rubber, 50 parts of N234, 2 parts of stearic acid, 1.5 parts of antioxidant RD, 1.2 parts of thiourea derivatives, 1.5 parts of microcrystalline wax, 5 parts of zinc oxide, 1.5 parts of sulfur powder, and 1 part of accelerator NS.
[0058] The mixing conditions of the tire rubber composition are as follows: when the temperature of the internal mixer is raised to 90°C, the natural rubber is added to the internal mixer and mixed at a rate of 80 rpm for 30 seconds, and then the carbon black, stearic acid, antioxidant and microcrystalline wax are added to the internal mixer. When the temperature is continued to rise to 125°C, the drum is lifted and cleaned, and the total mixing time is about 240 seconds for rubber discharge, and the temperature is controlled at about 160°C. After the mixed rubber is cooled to room temperature, when the temperature of the open mixer is raised to 60°C, the sulfur and accelerator of the rubber are added to the open mixer and mixed until uniformly dispersed, and the temperature during the mixing process does not exceed 110°C.
[0059] Example 2
[0060] Preparation method of n-butylthiourea derivative 2: Add 2.64g n-butylthiourea and 8.49g bromobutyl into a 250ml three-necked flask, then add 50ml DMF (i.e., dimethylformamide) into the three-necked flask. After the n-butylthiourea and bromobutyl are completely dissolved by DMF, a DMF solution containing 6.68g sodium carbonate is added dropwise into the three-necked flask while stirring. After the addition is complete, heat to 90°C and react for 5h. After the reaction is completed, remove the solvent and excess reactants in the reaction solution by a rotary evaporator, then add ethanol to dissolve, filter to remove insoluble matter, and recrystallize the filtrate with ethanol-water 2-3 times, and dry to obtain n-butylthiourea derivative 2.
[0061] n-Butylthiourea derivative 2 was used to replace 6PPD as a tire rubber protective agent.
[0062] The n-butylthiourea derivative 1 was replaced by the n-butylthiourea derivative 2, and the other components and mixing conditions of the rubber composition were the same as those in Example 1.
[0063] Comparative Example 1
[0064] The tire rubber composition includes the following components: 100 parts of natural rubber, 50 parts of N234, 2 parts of stearic acid, 1.5 parts of antioxidant RD, 2 parts of 6PPD, 1.5 parts of microcrystalline wax, 5 parts of zinc oxide, 1.5 parts of sulfur powder, and 1 part of accelerator NS.
[0065] The mixing conditions of the tire rubber composition are as follows: when the internal mixer is heated to 90°C, the natural rubber is added to the internal mixer and mixed at a rate of 80 rpm for 30 seconds, and then carbon black, stearic acid, antioxidant and microcrystalline wax are added to the internal mixer. When the internal mixer is heated to 125°C, the drum is lifted and cleaned, and the total mixing time is about 240 seconds for rubber discharge, and the temperature is controlled at about 160°C. After the mixed rubber is cooled to room temperature, when the temperature of the open mixer is raised to 60°C, the sulfur and accelerator of the rubber are added to the open mixer and mixed until uniformly dispersed, and the temperature during the mixing process does not exceed 110°C.
[0066] Comparative Example 2
[0067] The tire rubber composition includes the following components: 100 parts of natural rubber, 50 parts of N234, 2 parts of stearic acid, 1.5 parts of antioxidant RD, 2 parts of n-butyl thiourea, 1.5 parts of microcrystalline wax, 5 parts of zinc oxide, 1.5 parts of sulfur powder, and 1 part of accelerator NS.
[0068] The mixing conditions of the tire rubber composition are as follows: the internal mixer is heated to 90°C, the natural rubber is added to the internal mixer, and mixed at a rate of 80 rpm for 30 seconds, and then carbon black, stearic acid, antioxidant, and microcrystalline wax are added to the internal mixer, and the temperature is continued to rise to 125°C, and the drum is lifted and cleaned, and the total mixing time is about 240 seconds for rubber discharge, and the temperature is controlled at about 160°C. When the mixed rubber is cooled to room temperature and the temperature of the open mixer is raised to 60°C, the sulfur and accelerator of the rubber are added to the open mixer and mixed until uniformly dispersed, and the temperature during the mixing process does not exceed 110°C.
[0069] Effect Example
[0070] The tire rubber prepared in Example 1-2 and Comparative Example 1-2 was subjected to scorch time and anti-aging tests.
[0071] The scorch time test is a test used to evaluate the early vulcanization phenomenon of rubber materials during processing. It is mainly used to measure the processing safety of rubber materials, that is, the time consumed by the heat accumulation effect during processing, and the time the rubber material maintains fluidity in the thermal model.
[0072] T5 and T25 are important parameters used in the rubber industry to evaluate the processing safety of rubber materials.
[0073] T5 (Mooney scorch time): refers to the time from the start of the experiment to the time when the viscosity of the rubber drops to the lowest point and then rises by 5 Mooney values. T5 is tested using a large rotor and reflects the early vulcanization characteristics of the rubber during the processing, thereby obtaining the processing safety of the rubber.
[0074] T25 (Mooney vulcanization time): refers to the time from the start of the experiment to the time when the viscosity of the rubber drops to the lowest point and then rises by 25 Mooney values. This parameter is used to evaluate the vulcanization rate of the rubber, that is, the time required for the rubber to reach a certain degree of vulcanization from the beginning of vulcanization.
[0075] The scorch time T5 and T25 are used to evaluate the processing safety of the rubber compound and guide the adjustment and optimization of the production process. If the scorch time is too short, it means that the rubber compound is prone to premature vulcanization during processing, which may lead to a decrease in product quality or even an increase in scrap rate; if the scorch time is too long, it may extend the vulcanization cycle and reduce production efficiency.
[0076] Normalized scorch time refers to adjusting the scorch time to a uniform standard condition, which is convenient for comparing the scorch performance of different rubber formulations or under different conditions. This normalization process helps to eliminate the influence of different test conditions on the results, making the scorch time data more comparable.
[0077] Rubber ozone aging test is a test method used to evaluate the aging performance of rubber materials under the action of ozone. Ozone aging refers to the aging and deterioration of rubber in the atmosphere due to the action of ozone. Ozone aging usually occurs first on the rubber surface, especially at the stress concentration point or at the interface between the compounding agent particles and the rubber. The aging conditions are: dynamic stretching, stretching frequency 0.5Hz, maximum elongation 10%, temperature 40℃, ozone concentration 100pphm, aging 72h.
[0078] The scorch time test results of the rubber of Examples 1-2 and Comparative Examples 1-2 are shown in Tables 1 and Figure 1 As shown in the figure, the results of the ozone aging test are as follows Figure 2 shown.
[0079] It can be seen from Table 1 that the T5 scorch time of Example 1 and Example 2 is greater than the T5 scorch time of Comparative Example 2, and the T25 scorch time of Example 1 and Example 2 is also greater than the T5 scorch time of Comparative Example 2, that is, the scorch time T5 and T25 of the n-butylthiourea derivative 1 and the n-butylthiourea derivative 2 are both greater than the scorch time of n-butylthiourea, indicating that the n-butylthiourea derivative obtained by modifying n-butylthiourea can prolong the scorch time.
[0080] Table 1 Scorch schedule of rubber of comparative example 1-2 and embodiment 1-2
[0081]
[0082] like Figure 1 As shown, the normalized scorch time of the n-butylthiourea derivative 1 of Example 1 and the n-butylthiourea derivative 2 of Example 2 are both longer than that of the n-butylthiourea of Comparative Example 2, indicating that the normalized scorch time of the n-butylthiourea derivative obtained by modifying the n-butylthiourea is longer.
[0083] In Comparative Example 2, n-butyl thiourea is used to replace 6PPD, and the rubber scorch time is greatly shortened. After ozone aging, the microcracks are slightly increased compared with Comparative Example 1; in Example 1, the rubber scorch time is similar to that of Comparative Example 1, but the microcracks are slightly increased compared with Control Sample 1 after ozone aging. In Example 2, the rubber scorch time is slightly reduced than that of Control Sample 1, and the picture after ozone aging is similar to that of Comparative Example 1, indicating that n-butyl thiourea derivatives 1 and 2 can replace 6PPD as rubber anti-ozone protective agents.
[0084] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.
Claims
1. A n-butylthiourea derivative, characterized in that: The structural formula of the n-butylthiourea derivative is as shown in Formula I: Wherein, R1, R2, and R3 are each independently an aromatic group, a cycloalkyl group, or an alkyl group; The aromatic structural formula is: The cycloalkyl structural formula is: The alkyl structural formula: -C n H 2n+1 , R4 and R5 are each independently an aromatic group, a cycloalkyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group, and n is an integer of 4 to 8.
2. A method for preparing the n-butylthiourea derivative according to claim 1, characterized in that: Putting n-butyl thiourea and a modifier into a reaction kettle, and adding a first organic solvent to dissolve them; dissolving an acid-binding agent in a second organic solvent, and adding the acid-binding agent dropwise to the reaction kettle while stirring, and heating the reaction kettle to react, thereby obtaining the n-butyl thiourea derivative; The structural formula of the n-butylthiourea is as shown in Formula II: The modifier is one or more of aromatic hydrocarbons, cycloalkanes or alkanes, wherein the aromatic hydrocarbon has a structural formula as shown in Formula III: The structural formula of the cycloalkane is as shown in Formula IV: The structural formula of the alkane is as shown in Formula V: R4 and R5 are each independently an aromatic group, a cycloalkyl group or an alkyl group having 1 to 6 carbon atoms, n is an integer of 4 to 8, and R6, R7, and R8 are each independently Br, I or OH.
3. The method for preparing the n-butylthiourea derivative according to claim 2, characterized in that: The acid binding agent is one or more of triethylamine, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, potassium bicarbonate and potassium hydroxide.
4. The method for preparing the n-butylthiourea derivative according to claim 2, characterized in that: The second organic solvent is the same as the first organic solvent, and the first organic solvent is one or more of dimethylformamide, dimethyl sulfoxide, ethanol, methanol, acetone, and chloroform.
5. The method for preparing the n-butylthiourea derivative according to claim 2, characterized in that: The molar ratio of the n-butyl thiourea to the modifier is 1:2-5.
6. The method for preparing the n-butylthiourea derivative according to claim 2, characterized in that: The reaction temperature is 50-120° C., and the reaction time is 4-20 hours.
7. Use of the n-butylthiourea derivative according to claim 1 in tire rubber.
8. The application according to claim 7, characterized in that: The n-butylthiourea derivative is used as a protective agent for tire rubber.
9. The use according to claim 7, characterized in that: The n-butylthiourea derivative can be used alone as a tire rubber protective agent, or used together with other tire rubber protective agents.
10. The use according to claim 7, characterized in that: The n-butyl thiourea derivative is used as an antiozonant for natural rubber, synthetic isoprene rubber, butadiene rubber, styrene-butadiene rubber and halogenated butyl rubber.