An antioxidant, a preparation method thereof, a catalyst for preparing the antioxidant, a preparation method thereof, and an application thereof

Abstract

The present application relates to a kind of catalyst for preparing antioxidant TMQ, the catalyst includes carrier and catalytically active component supported thereon, and the catalytically active component is tetrazole compound.The technical scheme of the present application, on the one hand, using the acidity of tetrazole compound prepares the catalyst containing carrier, avoids the use of strong acid catalyst, omits the process of liquid alkali neutralization, water separation, thereby reducing the generation of waste water;On the other hand, using the nature of tetrazole compound and long-chain organic amine forms supramolecular self-assembly, so as to save TMQ preparation process energy consumption.

Description

Technical Field

[0001] This invention belongs to the field of rubber additives, and relates to an antioxidant and its preparation method, as well as a catalyst for preparing the antioxidant, its preparation method, and its application. Background Technology

[0002] Antioxidant TMQ (also known as antioxidant RD) belongs to the ketone-amine class of antioxidants. Its main component is the di, tri, and tetrapolymers of 2,2,4-trimethyl-1,2-dihydroquinoline, and it is one of the rubber antioxidants with the largest demand in both domestic and international markets. Currently, the preparation of TMQ in China can be divided into "one-step" and "two-step" methods. The "one-step" method typically uses aniline and acetone as raw materials, and is prepared through a series of steps including salt formation, condensation, polymerization, neutralization, and distillation under the catalysis of acid catalysts, especially hydrochloric acid. Therefore, the preparation of antioxidant TMQ often faces problems such as severe equipment corrosion, huge consumption of alkaline water, and high costs for waste treatment. To overcome these technical shortcomings, seeking new catalytic materials and reducing hydrochloric acid consumption to reduce wastewater generation is of great significance for the environmentally friendly preparation of TMQ.

[0003] Besides hydrochloric acid, organic acids such as p-toluenesulfonic acid, benzenesulfonic acid, and phenolsulfonic acid can also be used as catalysts for the antioxidant TMQ. However, directly using organic acid catalysis also faces the challenges of requiring large amounts of alkali for neutralization and generating huge amounts of wastewater. Tetraazole compounds have free protons and possess properties similar to organic acids. They also contain an unsaturated five-membered heterocyclic structure that is approximately in the same plane, exhibiting an aromatic structure similar to benzene rings. Their acidity and electron-rich conjugated system allow them to generate various non-covalent interactions with other compounds, such as hydrogen bonding, π-π stacking, coordination, and electrostatic interactions, showing significant potential applications in supramolecular self-assembly. Therefore, we considered two approaches: firstly, modifying catalyst supports such as graphene oxide with tetraazole compounds to form stable acidic catalysts; secondly, after the TMQ preparation reaction is complete, adding long-chain organic amines to form supramolecular self-assemblies with tetraazole compounds to increase the hydrophobicity of the catalyst and facilitate separation. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an antioxidant and its preparation method, as well as a catalyst for preparing the antioxidant and its preparation method. The catalyst of this invention utilizes the acidity of tetrazolium compounds to prepare a supported catalyst, avoiding the use of strong acid catalysts and omitting the processes of liquid alkali neutralization and water separation, thereby reducing wastewater generation.

[0005] In a first aspect, the present invention provides a catalyst for preparing antioxidant TMQ, the catalyst comprising a support and a catalytically active component supported thereon, the catalytically active component being a tetrazolium compound.

[0006] According to some preferred embodiments of the present invention, the carrier is graphene oxide.

[0007] According to some embodiments of the present invention, the tetrazolium compounds include compounds containing one or two tetrazolium rings.

[0008] According to some preferred embodiments of the present invention, the tetrazolium compound is any one of phenyltetrazole, pyridinetetrazole, methyltetrazole, m-phenyltetrazole, p-aminophenyltetrazole, and m-phenyltetrazole.

[0009] According to some further preferred embodiments of the present invention, the tetrazolium compound is m-phenyltetrazolium.

[0010] A second aspect of the present invention provides a method for preparing a catalyst for preparing the antioxidant TMQ, the method comprising the following steps:

[0011] S1 disperses the carrier in a solvent to obtain a carrier dispersion;

[0012] S2 dissolves the tetrazolium compound in the carrier dispersion to obtain a reaction solution;

[0013] S3 After stirring, filtering, and washing the reaction solution obtained in step S2, the catalyst is obtained.

[0014] According to some preferred embodiments of the present invention, in step S1, the dispersion is achieved by stirring or ultrasonication.

[0015] According to some preferred embodiments of the present invention, in step S1, the solvent is methanol, ethanol, dichloromethane, chloroform, acetone, acetonitrile, ethyl acetate, N,N-dimethylformamide, and dimethyl sulfoxide.

[0016] According to some further preferred embodiments of the present invention, in step S1, the solvent is methanol or ethanol.

[0017] According to some preferred embodiments of the present invention, in step S2, the mass ratio of the tetrazolium compound to graphene is 1:1 to 1:5.

[0018] According to some further preferred embodiments of the present invention, in step S2, the mass ratio of the tetrazolium compound to graphene is 1:1 to 1:2.

[0019] According to some preferred embodiments of the present invention, in step S3, the stirring time is 0 to 72 hours.

[0020] According to some further preferred embodiments of the present invention, in step S3, the stirring time is 24 to 48 hours.

[0021] According to some preferred embodiments of the present invention, in step S3, washing is performed using the solvent or deionized water.

[0022] According to some preferred embodiments of the present invention, in step S3, the washing method is centrifugal washing and dialysis.

[0023] According to some preferred embodiments of the present invention, step S3 further includes lyophilizing the washed catalyst.

[0024] A third aspect of the present invention provides a method for preparing a rubber antioxidant TMQ, wherein aniline and acetone are reacted to obtain the antioxidant TMQ by using toluene as a solvent and under the conditions of using the catalyst described above or the catalyst prepared according to the preparation method described above.

[0025] According to some preferred embodiments of the present invention, the weight ratio of aniline to acetone is 1:1 to 10.

[0026] According to some further preferred embodiments of the present invention, the weight ratio of aniline to acetone is 1:6 to 10.

[0027] According to some preferred embodiments of the present invention, the weight ratio of the catalyst to aniline is 0.0005 to 0.5:1.

[0028] According to some further preferred embodiments of the present invention, the weight ratio of the catalyst to aniline is 0.05 to 0.3:1.

[0029] According to some preferred embodiments of the present invention, the reaction temperature is 70–110°C.

[0030] According to some further preferred embodiments of the present invention, the reaction temperature is 80–100°C.

[0031] According to some preferred embodiments of the present invention, the reaction time is 4 to 10 hours.

[0032] According to some further preferred embodiments of the present invention, the reaction time is 6 to 8 hours.

[0033] According to some embodiments of the present invention, the separation of the catalyst from TMQ is further included, specifically, the following steps are included:

[0034] After the reaction is complete, a long-chain organic amine is added to the solution in S1.

[0035] S2 is separated from TMQ by natural sedimentation and filtration.

[0036] Specifically, the preparation method of the rubber antioxidant TMQ involves adding a catalyst for TMQ preparation to aniline and acetone, using toluene as a solvent, mixing and heating to the reaction temperature. After reacting for a period of time, a long-chain organic amine is added and stirred to dissolve the long-chain organic chain and form a supramolecular self-assembly with the tetrazolium compound on the catalyst, which then naturally settles and separates from the TMQ. The supramolecular self-assembly refers to a regularly structured assembly spontaneously formed by the tetrazolium compound and the long-chain organic chain in synergy with graphene oxide through non-covalent bonds such as hydrogen bonding, π-π stacking, coordination, and electrostatic interactions. This invention utilizes the properties of tetrazolium compounds to form supramolecular self-assemblies with long-chain organic amines, facilitating catalyst separation and thus saving energy in the TMQ preparation process.

[0037] According to some embodiments of the present invention, the long-chain organic amine is an alkylamine with 10-20 carbon atoms.

[0038] According to some preferred embodiments of the present invention, the long-chain organic amine is dodecylamine, tetradecylamine, hexadecylamine, or octadecylamine.

[0039] According to some further preferred embodiments of the present invention, the long-chain organic amine is octadecylamine.

[0040] According to some embodiments of the present invention, the natural settling time is 2 to 4 hours.

[0041] A fourth aspect of the present invention provides a rubber antioxidant TMQ prepared using the catalyst described above or the catalyst prepared according to the preparation method described above.

[0042] A fifth aspect of the present invention provides the use of the catalyst described above or the catalyst prepared according to the preparation method described above in the preparation of antioxidant TMQ. Detailed Implementation

[0043] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the invention. It should also be understood that the method steps and related data involved in this embodiment do not preclude the insertion of other method steps and combinations of other data proportions. The endpoints and any values ​​of the ranges disclosed herein are not limited to those precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values, and will also be considered within the scope of the present invention.

[0044] Unless otherwise specified, all chemical reagents used in the description of the embodiments can be purchased from chemical reagent companies.

[0045] Example 1

[0046] 20 g of graphene oxide was weighed and thoroughly dispersed in 4000 g of ethanol. 30 g of m-phenylenetetrazole was weighed and completely dissolved in the system, and then stirred for 36 h. After stirring, the mixture was washed with ethanol and deionized water to remove free m-phenylenetetrazole, and then the product was freeze-dried to obtain the catalyst for TMQ preparation.

[0047] 10g of TMQ preparation catalyst, 93g of aniline, and 890g of acetone were added to 500g of toluene, and the mixture was reacted at 100℃ for 6 hours. After the reaction was completed, 5g of octadecylamine was added, and the mixture was stirred to form supramolecular self-assembled structures. The structures were allowed to stand for 4 hours to settle, and the antioxidant TMQ was directly separated. High-performance liquid chromatography (HPLC) analysis of the antioxidant TMQ product showed that the dimer content was 26.8%, the trimer content was 20.62%, and the tetramer content was 11.37%. The dimer, trimer, and tetramer contents of TMQ were in a relatively ideal state.

[0048] Example 2

[0049] 20g of graphene oxide was weighed and thoroughly dispersed in 4000g of ethanol. 30g of m-phenylenetetrazole was weighed and completely dissolved in the system, then stirred for 36h. After stirring, the mixture was washed with ethanol and deionized water to remove free m-phenylenetetrazole, and the product was then lyophilized to obtain the catalyst for TMQ preparation. 1g of the TMQ preparation catalyst, 93g of aniline, and 890g of acetone were added to 500g of toluene, and the mixture was reacted at 100℃ for 6h. After the reaction was complete, 5g of octadecylamine was added, and the mixture was stirred to form supramolecular self-assemblies. The mixture was allowed to stand for 4h to settle, and the antioxidant TMQ was directly separated. High-performance liquid chromatography (HPLC) analysis of the antioxidant TMQ product showed that the dimer content was 7.39%, the trimer content was 0.39%, and the tetramer content was undetectable. The low content of dimer, trimer, and tetramers in TMQ indicates a low degree of reaction.

[0050] Example 3

[0051] 20g of graphene oxide was weighed and thoroughly dispersed in 4000g of ethanol. 30g of m-phenylenetetrazolium was weighed and completely dissolved in the system, then stirred for 36h. After stirring, the mixture was washed with ethanol and deionized water to remove free m-phenylenetetrazolium, and the product was then lyophilized to obtain the catalyst for TMQ preparation. 10g of the TMQ preparation catalyst, 93g of aniline, and 890g of acetone were added to 500g of toluene, and the mixture was reacted at 50℃ for 6h. After the reaction was complete, 5g of octadecylamine was added, and the mixture was stirred to form supramolecular self-assemblies. The mixture was allowed to stand for 4h to settle, and the antioxidant TMQ was directly separated. High-performance liquid chromatography analysis of the antioxidant TMQ product showed that the content of dimers, trimers, and tetramers of TMQ was not detected, indicating that the reaction was essentially incomplete.

[0052] Example 4

[0053] 20g of graphene oxide was weighed and thoroughly dispersed in 4000g of ethanol. 30g of m-phenylenetetrazole was weighed and completely dissolved in the system, then stirred for 36h. After stirring, the mixture was washed with ethanol and deionized water to remove free m-phenylenetetrazole, and the product was then directly dried to obtain the catalyst for TMQ preparation. 10g of the TMQ preparation catalyst, 93g of aniline, and 890g of acetone were added to 500g of toluene, and the mixture was reacted at 100℃ for 6h. After the reaction was complete, 5g of octadecylamine was added, and the mixture was stirred to form supramolecular self-assemblies. After standing for 4h to allow sedimentation, the antioxidant TMQ was directly separated. High-performance liquid chromatography (HPLC) analysis of the antioxidant TMQ product showed that the content of dimers, trimers, and tetramers of TMQ was not detected, indicating that the reaction was essentially incomplete. The reason for this is that the graphene oxide support agglomerated and could not be dispersed under directly dried conditions, thus failing to provide catalysis.

[0054] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for preparing a rubber antioxidant TMQ, characterized in that, include: Antioxidant TMQ is prepared by reacting aniline and acetone in the presence of a catalyst using toluene as a solvent; the catalyst includes a support and a catalytically active component supported thereon, wherein the catalytically active component is a tetrazolium compound; The weight ratio of aniline to acetone is 1:1 to 10; The weight ratio of the catalyst to aniline is 0.0005~0.5:1; The reaction temperature is 70~110℃; The reaction time is 4 to 10 hours.

2. The preparation method according to claim 1, characterized in that, The carrier is graphene oxide.

3. The preparation method according to claim 1, characterized in that, The weight ratio of aniline to acetone is 1:6~10.

4. The preparation method according to claim 1, characterized in that, The catalyst to aniline has a weight ratio of 0.05 to 0.3:

1.

5. The preparation method according to claim 1, characterized in that, The reaction temperature is 80~100℃; and / or the reaction time is 6~8 h.

6. The preparation method according to claim 1, characterized in that, The tetrazolium compounds are selected from compounds containing one or two tetrazolium rings.

7. The preparation method according to claim 6, characterized in that, The tetrazolium compound is any one of phenyltetrazolium, pyridinetetrazolium, methyltetrazolium, m-phenyltetrazolium, p-aminophenyltetrazolium, and m-phenyltetrazolium.

8. The preparation method according to claim 7, characterized in that, The tetrazolium compound is selected from m-phenyltetrazolium.

9. The preparation method according to any one of claims 1-8, characterized in that, The method for preparing the catalyst includes the following steps: S1. The support is dispersed in a solvent to obtain a support dispersion, wherein the support is graphene oxide; S2. The tetrazolium compound is dissolved in the carrier dispersion to obtain a reaction solution; S3 After stirring, filtering, and washing the reaction solution obtained in step S2, the catalyst is obtained.

10. The preparation method according to claim 9, characterized in that, In step S1, the dispersion is achieved by stirring or ultrasonication; and / or, In step S1, the solvent is selected from methanol, ethanol, dichloromethane, chloroform, acetone, acetonitrile, ethyl acetate, N,N-dimethylformamide, and dimethyl sulfoxide; and / or, In step S2, the mass ratio of the tetrazolium compound to graphene oxide is 1:1 to 1:5; and / or, In step S3, the stirring time is 0~72 h; and / or, In step S3, washing is performed using the solvent or deionized water; and / or, In step S3, the washing method is centrifugal washing and dialysis; and / or, Step S3 also includes lyophilizing the washed catalyst.

11. The preparation method according to claim 10, characterized in that, The solvent is selected from methanol and / or ethanol; and / or, the mass ratio of the tetrazolium compound to graphene oxide is 1:1 to 1:2; and / or, the stirring time is 24 to 48 hours.

12. The preparation method according to any one of claims 1-8, characterized in that, It also includes the separation of the catalyst from TMQ, specifically including the following steps: After the reaction is complete, a long-chain organic amine is added to the solution; S2 is separated from TMQ by natural sedimentation and filtration.

13. The preparation method according to claim 12, characterized in that, The long-chain organic amine is an alkylamine with 10-20 carbon atoms.

14. The preparation method according to claim 13, characterized in that, The long-chain organic amines are dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine.

15. The preparation method according to claim 14, characterized in that, The long-chain organic amine is octadecylamine.

16. The preparation method according to claim 12, characterized in that, The natural settling time is 2 to 4 hours.

17. The application of a catalyst in the preparation of antioxidant TMQ, characterized in that, The catalyst comprises a support and a catalytically active component loaded thereon, wherein the catalytically active component is a tetrazolium compound.

18. The application according to claim 17, characterized in that, The carrier is graphene oxide.

19. The application according to claim 17, characterized in that, The tetrazolium compounds are selected from compounds containing one or two tetrazolium rings.

20. The application according to claim 19, characterized in that, The tetrazolium compound is any one of phenyltetrazolium, pyridinetetrazolium, methyltetrazolium, m-phenyltetrazolium, p-aminophenyltetrazolium, and m-phenyltetrazolium.