Rubber anti-aging agent, preparation method and application

Abstract

The invention belongs to the field of anti-aging agents, and particularly relates to a rubber anti-aging agent as well as a preparation method and application thereof. The rubber anti-aging agent provided by the invention has a structure as shown in a formula I compound. Compared with the existing other p-phenylenediamine anti-aging agents, the rubber anti-aging agent provided by the invention has better thermo-oxidative aging resistance and migration resistance.

Description

Technical Field

[0001] This invention belongs to the field of antioxidants, specifically relating to a rubber antioxidant, its preparation method, and its application. Background Technology

[0002] p-Phenylenediamine compounds, due to their excellent overall protective properties, are often used as mainstream antioxidants in rubber products, such as automobile tires. Their main varieties include: antioxidant 4010 / CPPD (N-phenyl- -cyclohexyl-p-phenylenediamine), antioxidant 4020 / 6PPD (N-phenyl- (1,3-Dimethylbutyl)-p-phenylenediamine, etc. These substances can effectively slow down the degradation of rubber products, significantly extend their service life, and have high economic and industrial value.

[0003] Although these compounds have excellent properties such as anti-ozone, anti-oxidation, heat resistance, and resistance to flexural cracking, they are prone to physical loss and failure during use. That is, small molecules permeate out of rubber products through volatilization, migration, and extraction, consuming antioxidants, reducing their efficiency, and the migrated antioxidants can also pollute the environment. Summary of the Invention

[0004] This invention addresses the aforementioned problems in existing technologies by proposing a novel p-phenylenediamine-based antioxidant with a novel molecular structure. Compared to traditional antioxidants 6PPD and 4010, the p-phenylenediamine-based antioxidant of this invention exhibits superior resistance to thermo-oxidative aging and migration resistance, thus imparting better thermo-oxidative aging resistance (especially long-term thermo-oxidative aging resistance) and colorfastness to rubber compositions or rubber products. Specifically, this invention provides a compound of formula I that can be used as a rubber antioxidant: .

[0005] Another aspect of the present invention provides a method for preparing a compound of formula I, the method comprising: reacting 4-aminodiphenylamine and 2-cyclohexylcyclohexanone by a condensation-hydroalkylation reaction catalyzed by a noble metal catalyst to generate a compound of formula I.

[0006] In one or more embodiments, the molar ratio of 4-aminodiphenylamine to 2-cyclohexylcyclohexanone is 1:(3-10).

[0007] In one or more embodiments, the mass ratio of the noble metal catalyst to 4-aminodiphenylamine is (1-10):100.

[0008] In one or more embodiments, the temperature of the condensation-hydroalkylation reaction is 180-250°C.

[0009] In one or more embodiments, the hydrogen pressure in the condensation-hydroalkylation reaction is 0.5-3 MPa.

[0010] In one or more embodiments, the condensation-hydroalkylation reaction takes 3-7 hours.

[0011] In one or more embodiments, the noble metal catalyst comprises a noble metal and a support, wherein the noble metal has a mass fraction of 1%-10% in the noble metal catalyst; the noble metal is one or more selected from Pt, Pd, Ru and Rh; and the support is one or more selected from carbon support, alumina, silica gel and molecular sieve.

[0012] In one or more embodiments, the method for preparing 2-cyclohexylcyclohexanone includes: hydrogenating a cyclohexanone dimer to obtain 2-cyclohexylcyclohexanone; wherein the cyclohexanone dimer is selected from one or both of 2-(1-cyclohexenyl)cyclohexanone and cyclohexylenecyclohexanone.

[0013] In one or more embodiments, the hydrogenation reaction is carried out under the catalysis of a noble metal catalyst, wherein the mass ratio of the noble metal catalyst to the cyclohexanone dimer is (1-10):100; the noble metal catalyst comprises a noble metal and a support, wherein the mass fraction of the noble metal in the noble metal catalyst is 1-10%; the noble metal is one or more selected from Pt, Pd, Ru and Rh; the support is one or more selected from carbon support, alumina, silica gel and molecular sieve.

[0014] In one or more embodiments, the hydrogenation reaction is carried out at a temperature of 120-180°C.

[0015] In one or more embodiments, the hydrogen pressure in the hydrogenation reaction is 0.5-3 MPa.

[0016] In one or more embodiments, the hydrogenation reaction lasts for 4-7 hours.

[0017] Another aspect of the present invention provides a rubber composition comprising a diene elastomer and a compound of formula I as an antioxidant.

[0018] In one or more embodiments, the compound of formula I has a mass fraction of 1-4% in the rubber composition.

[0019] Another aspect of the present invention provides a rubber article comprising the rubber composition described in any embodiment of the present invention.

[0020] In one or more embodiments, the rubber product is a car tire.

[0021] Another aspect of the invention provides the use of the compound of formula I in improving the heat and oxygen aging resistance and / or colorfastness resistance of rubber compositions or rubber articles.

[0022] The antioxidant of this invention introduces a large-molecule electron-donating dicyclohexyl group, which reduces the NH bond dissociation energy, stabilizes free radical intermediates, and significantly promotes the formation of hydrogen free radicals from amine groups, while retaining the main molecular structure of antioxidant 4010. Compared with other p-phenylenediamine antioxidants, it exhibits more significant resistance to heat and oxygen aging, and better migration resistance. Detailed Implementation

[0023] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used herein are explained and defined in general terms below. Unless otherwise specified, all technical and scientific terms used herein have the common meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0024] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0025] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” “A is basically composed of B and C” and “A is composed of B and C” should be considered as having been disclosed in this document.

[0026] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0027] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0028] In this article, the sum of the percentages of all components in the composition is 100%.

[0029] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope of this invention.

[0030] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0031] This invention provides a compound of formula I having the structure shown below: .

[0032] In this article, the compound of formula I is named N-bicyclohexyl-N'-phenyl-p-phenylenediamine, also known as antioxidant 4010C.

[0033] This invention also provides a method for preparing the compound of formula I, the synthetic route of which is as follows: .

[0034] 4-Aminodiphenylamine ( ) and 2-cyclohexylcyclohexanone ( Under the catalysis of a noble metal catalyst, N-bicyclohexyl-N'-phenyl-p-phenylenediamine, i.e., compound I, is generated in one step through a condensation-hydroalkylation reaction.

[0035] In some embodiments, the molar ratio of 4-aminodiphenylamine to 2-cyclohexylcyclohexanone is 1:(3-10), such as 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1:10, or any range between two values, such as 1:3-1:6, 1:3.5-1:5.5.

[0036] In some embodiments, the mass ratio of the noble metal catalyst to 4-aminodiphenylamine is (1-10):100, for example, 1:100, 1.5:100, 2:100, 2.5:100, 3:100, 3.5:100, 4:100, 4.5:100, 5:100, 5.5:100, 6:100, 6.5:100, 7:100, 7.5:100, 8:100, 8.5:100, 9:100, 9.5:100, 10:100, or any range of any two values, such as 1.5:100-3.5:100, 2:100-3.5:100.

[0037] In some embodiments, the temperature of the condensation-hydroalkylation reaction is 180-250°C, for example, 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, or any range between two of these values.

[0038] In some embodiments, the hydrogen pressure in the condensation-hydroalkylation reaction is 0.5-3 MPa, for example, 0.5 MPa, 0.55 MPa, 0.6 MPa, 0.65 MPa, 0.7 MPa, 0.75 MPa, 0.8 MPa, 0.85 MPa, 0.9 MPa, 0.95 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, or any range between two values.

[0039] In some embodiments, the condensation-hydroalkylation reaction takes 3-7 hours, for example, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, or any range between two values.

[0040] In some embodiments, the noble metal catalyst comprises a noble metal and a support, wherein the mass fraction of the noble metal in the noble metal catalyst is 1-10%, for example, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, or any range between two values, for example, 1%-5%; the noble metal includes, but is not limited to, one or more of Pt, Pd, Ru, and Rh; the support includes, but is not limited to, one or more of carbon support, alumina, silica gel, and molecular sieves.

[0041] In this invention, 2-cyclohexylcyclohexanone can be prepared by the following method:

[0042] The cyclohexanone dimer is hydrogenated to obtain 2-cyclohexylcyclohexanone; the cyclohexanone dimer is selected from one or both of 2-(1-cyclohexenyl)cyclohexanone and cyclohexylenecyclohexanone.

[0043] In some implementations, the hydrogenation reaction is carried out under the catalysis of a noble metal catalyst, with the mass ratio of the noble metal catalyst to the cyclohexanone dimer being (1-10):100, for example 1:100, 1.5:100, 2:100, 2.5:100, 3:100, 3.5:100, 4:100, 4.5:100, 5:100, 5.5:100, 6:100, 6.5:100, 7:100, 7.5:100, 8:100, 8.5:100, 9:100, 9.5:100, 10:100, or any range of two values, such as 1:100-4.0:100. 1:100-4.5:100; wherein, the noble metal catalyst includes a noble metal and a support, and the mass fraction of the noble metal in the noble metal catalyst is 1-10%, for example, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, or any range between two values, for example, 1%-3%; the noble metal in the noble metal catalyst includes, but is not limited to, one or more of Pt, Pd, Ru and Rh; the support includes, but is not limited to, one or more of carbon support, alumina, silica gel and molecular sieve.

[0044] In some implementations, the reaction temperature for hydrogenation is 120-180°C, for example, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 180°C, or any range between two values.

[0045] In some embodiments, the hydrogen pressure in the hydrogenation reaction is 0.5-3 MPa, for example, 0.5 MPa, 0.55 MPa, 0.6 MPa, 0.65 MPa, 0.7 MPa, 0.75 MPa, 0.8 MPa, 0.85 MPa, 0.9 MPa, 0.95 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, or any range between two values.

[0046] In some embodiments, the reaction time of the hydrogenation reaction is 4-7 hours, for example, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, or any range between two values.

[0047] In some embodiments, the hydrogenation reaction is followed by a post-treatment process. In some preferred embodiments, the post-treatment process includes filtration and distillation. In some more preferred embodiments, the filtration is hot filtration and the distillation is vacuum distillation.

[0048] The present invention also provides a rubber composition comprising a diene elastomer and a compound of formula I of the present invention as an antioxidant. The compound of formula I will be referred to below as the antioxidant of the present invention.

[0049] In the rubber composition of the present invention, the antioxidant has a mass fraction of 1-4%, for example, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, or any range between two values.

[0050] The present invention also provides a rubber article comprising the rubber composition described in any embodiment of the present invention. The rubber article may be a tire, rubber footwear, a sealed container lid, a strip, a sound insulation plate, a vibration damping pad, etc. In some embodiments, the rubber article is a tire, such as the tire tread, belt layer, and sidewall of a tire. The belt layer of the tire may also contain reinforcing materials conventionally used in the art, in addition to the rubber composition of the present invention.

[0051] This invention also provides the use of the Formula I compound of this invention in improving the long-term heat and oxygen aging resistance of rubber or rubber articles. Preferably, the rubber article is a tire. The use includes adding the Formula I compound of any embodiment herein as an antioxidant to the rubber or rubber article.

[0052] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the invention. The methods, reagents, and materials used in the embodiments and comparative examples are conventional methods, reagents, and materials in the art, unless otherwise stated. The starting material compounds in the embodiments and comparative examples are all commercially available.

[0053] In this invention, the gas chromatography (GC) analysis instrument used is a gas chromatograph (Agilent Technologies (China) Co., Ltd., 8890).

[0054] Mass spectrometry analysis was performed using a G2-XS liquid chromatography-mass spectrometry (LC-MS) analyzer (Waters Corporation, USA).

[0055] The melting point was obtained by testing with a melting point apparatus (Mettler Toledo International Ltd., MP90).

[0056] The instrument used for measuring nuclear magnetic resonance was an Avance III nuclear magnetic resonance spectrometer from Bruker GmbH, Germany.

[0057] Preparation of o-cyclohexylcyclohexanone: Synthesis example 1 150g of 2-(1-cyclohexenyl)cyclohexanone ( 1.5g of 3% Pt / C catalyst (each 100g of Pt / C catalyst contains 3g of platinum, and the remaining 97g is activated carbon support) was added in one go to a 250mL stainless steel high-pressure reactor. The reactor lid was sealed, and the reactor was purged three times with nitrogen and three times with hydrogen, respectively. The reaction temperature was controlled at 150℃, the hydrogen pressure at 2.0MPa, and the stirring speed at 800-1000rpm. The reaction was continued until the pressure inside the reactor remained essentially constant. Samples were taken for GC analysis. The reaction took approximately 6 hours until the conversion of 2-(1-cyclohexenyl)cyclohexanone was complete. The temperature was lowered to 50℃, and the hydrogenated liquid was transferred and filtered while hot to remove the catalyst. The filtrate was then distilled under reduced pressure (-0.098MPa, 130℃) to remove light components, yielding o-cyclohexylcyclohexanone. (Colorless and transparent liquid), GC detection showed a purity of 98.5%, with a yield of 98.9%; LC-MS (m / z): [M+H] + It is 180.1518.

[0058] Synthesis example 2

[0059] 120g of 2-(1-cyclohexenyl)cyclohexanone ( 2g of 1% Pt / C catalyst was added in a single batch to a 250mL stainless steel high-pressure reactor. The reactor lid was sealed, and the reactor was purged three times with nitrogen and three times with hydrogen, respectively. The reaction temperature was controlled at 180℃, the hydrogen pressure at 1.0MPa, and the stirring speed at 800-1000rpm. GC monitoring was performed until the conversion of 2-(1-cyclohexenyl)cyclohexanone was complete, which took approximately 5 hours. The mixture was then cooled to 50℃, and the hydrogenated solution was transferred and filtered while hot to remove the catalyst. The filtrate was then distilled under reduced pressure (-0.098MPa, 140℃) to remove light components, yielding o-cyclohexylcyclohexanone. GC analysis showed a purity of 99.5%, with a yield of 98.1%.

[0060] Synthesis example 3

[0061] 100g of cyclohexanediene-1,4-cyclohexanone ( 3.0 g of 1% Pt / C catalyst was added in a single batch to a 250 mL stainless steel high-pressure reactor. The reactor lid was sealed, and the reactor was purged three times with nitrogen and three times with hydrogen, respectively. The reaction temperature was controlled at 120 °C, the hydrogen pressure at 0.5 MPa, and the stirring speed at 800-1000 rpm. The reaction was continued until the pressure inside the reactor remained essentially constant. Samples were taken for GC analysis. The cyclohexylenecyclohexanone was completely converted, and the reaction time was approximately 7 hours. The temperature was lowered to 50 °C, and the hydrogenated liquid was transferred and filtered while hot to remove the catalyst. The filtrate was then distilled under reduced pressure (-0.098 MPa, 140 °C) to remove light components, yielding o-cyclohexylcyclohexanone. GC analysis showed a purity of 97.8%, with a yield of 98.6%.

[0062] Synthesis example 4

[0063] 120g of cyclohexylene dicyclohexanone ( 5.0 g of 1% Pt / C catalyst was added in a single batch to a 250 mL stainless steel high-pressure reactor. The reactor lid was sealed, and the reactor was purged three times with nitrogen and three times with hydrogen, respectively. The reaction temperature was controlled at 120 °C, the hydrogen pressure at 1.0 MPa, and the stirring speed at 800-1000 rpm. The reaction was continued until the pressure inside the reactor remained essentially constant. Samples were taken for GC analysis. The cyclohexylenecyclohexanone was completely converted, and the reaction time was approximately 4 hours. The temperature was lowered to 50 °C, and the hydrogenated liquid was transferred and filtered while hot to remove the catalyst. The filtrate was then distilled under reduced pressure (-0.098 MPa, 150 °C) to remove light components, yielding o-cyclohexylcyclohexanone. GC analysis showed a purity of 98.3%, with a yield of 98.8%.

[0064] Synthesis example 5

[0065] 160g of cyclohexanone dimer (i.e., 2-(1-cyclohexenyl)cyclohexanone) was added. ) and cyclohexylene dicyclohexanone ( A mixture (purchased from Shanghai Titan Technology Co., Ltd., containing 85% 2-(1-cyclohexenyl)cyclohexanone and 15% cyclohexylenecyclohexanone (mass percentage)) was added in a single batch to a 250 mL stainless steel high-pressure reactor. The reactor lid was sealed, and the reactor was purged three times with nitrogen and three times with hydrogen, respectively. The reaction temperature was controlled at 180℃, the hydrogen pressure at 3.0 MPa, and the stirring speed at 800-1000 rpm. The pressure inside the reactor remained essentially constant. Samples were taken for GC analysis until the cyclohexanone dimer was completely converted, with a reaction time of approximately 5 hours. The mixture was cooled to 50℃, and the hydrogenated liquid was transferred and filtered while hot to remove the catalyst. The filtrate was then distilled under reduced pressure (-0.098 MPa, 155℃) to remove light components, yielding o-cyclohexylcyclohexanone. GC analysis showed a purity of 97.9%, with a yield of 99.1%.

[0066] Synthesis example 6

[0067] 2-(1-cyclohexenyl)cyclohexanone ( 80g, cyclohexylene dicyclohexanone ( 20g and 2.0g of 3% Pt / C catalyst were added in a single batch to a 250mL stainless steel high-pressure reactor. The reactor lid was sealed, and the reactor was purged three times with nitrogen and three times with hydrogen, respectively. The reaction temperature was controlled at 150℃, the hydrogen pressure at 1.5MPa, and the stirring speed at 800-1000rpm. The pressure inside the reactor remained essentially constant. Samples were taken for GC analysis until the cyclohexanone dimer was completely converted, with a reaction time of approximately 5 hours. The mixture was cooled to 50℃, and the hydrogenated liquid was transferred and filtered while hot to remove the catalyst. The filtrate was then distilled under reduced pressure (-0.098MPa, 160℃) to remove light components, yielding a colorless and transparent liquid of o-cyclohexylcyclohexanone. GC analysis showed a purity of 98.2%, with a yield of 97.9%.

[0068] Preparation of antioxidant 4010C: Example 1 100g (0.55mol) of o-cyclohexylcyclohexanone, 20g (0.1mol) of 4-aminodiphenylamine, and 0.5g of 3% Pt / C catalyst were added in one batch to a 250mL stainless steel high-pressure reactor. The reactor lid was sealed, and the reactor was purged three times with nitrogen and three times with hydrogen, respectively. The reaction temperature was controlled at 200℃, the hydrogen pressure at 2.0MPa, and the stirring speed at 800-1000rpm. Samples were taken periodically for GC analysis until the 4-aminodiphenylamine was completely converted, which took about 5 hours. The temperature was lowered to 80℃, the hydrogenated liquid was transferred, and the catalyst was removed by hot filtration. The filtrate was then distilled under reduced pressure (-0.098MPa, 220℃) to remove the water and light components generated in the reaction, as well as a small amount of unreacted o-cyclohexylcyclohexanone, yielding a purple solid, namely antioxidant 4010C. The content was 97.8% according to GC analysis, the yield was 99.8%, and the melting point was 109℃; LC-MS (m / z): [M+H] + The value is 348.2569.

[0069] 1H NMR spectrum: 1 H NMR (400 MHz, Chloroform-d) δ 7.22 – 7.14 (m, 2H), 7.02 – 6.97 (m,2H), 6.87 – 6.81 (m, 2H), 6.80 – 6.74 (m, 1H), 6.58 (d, J = 8.7 Hz, 2H), 5.35(s, 1H), 3.77 (d, J = 3.2 Hz, 1H), 2.11 – 2.01 (m, 1H), 1.88 – 1.59 (m, 8H), 1.48-1.38 (m, 2H), 1.30 – 1.09 (m, 8H), 0.92 – 0.80 (m, 2H). Carbon NMR spectrum: 13 C NMR (101 MHz, Chloroform-d) δ 146.53, 144.27, 131.63, 129.21,124.30, 118.52, 114.66, 113.78, 48.33, 46.11, 38.95, 31.21, 30.23, 29.33,26.69, 26.54, 26.49, 26.28, 24.60, 20.39.

[0070] Example 2

[0071] 100g (0.55mol) of o-cyclohexylcyclohexanone, 30g (0.15mol) of 4-aminodiphenylamine, and 1.0g of 1% Pt / C catalyst were added in a single batch to a 250mL stainless steel high-pressure reactor. The reactor lid was sealed, and the reactor was purged three times with nitrogen and three times with hydrogen, respectively. The reaction temperature was controlled at 250℃, the hydrogen pressure at 3.0MPa, and the stirring speed at 800-1000rpm. Samples were periodically taken for GC analysis until the 4-aminodiphenylamine was completely converted, which took approximately 7 hours. The mixture was then cooled to 80℃, the hydrogenated liquid was transferred, and the catalyst was removed by hot filtration. The filtrate was then subjected to vacuum distillation (-0.098MPa, 230℃) to remove the water and light components generated in the reaction, as well as a small amount of unreacted o-cyclohexylcyclohexanone, yielding antioxidant 4010C. The GC analysis showed a purity of 97.3% and a yield of 98.3%.

[0072] Example 3

[0073] 100g (0.55mol) of o-cyclohexylcyclohexanone, 30g (0.15mol) of 4-aminodiphenylamine, and 0.6g of 5% Pt / C catalyst were added in a single batch to a 250mL stainless steel high-pressure reactor. The reactor lid was sealed, and the reactor was purged three times with nitrogen and three times with hydrogen, respectively. The reaction temperature was controlled at 180℃, the hydrogen pressure at 1.0MPa, and the stirring speed at 800-1000rpm. Samples were periodically taken for GC analysis until the 4-aminodiphenylamine was completely converted, which took approximately 3 hours. The mixture was then cooled to 80℃, the hydrogenated liquid was transferred, and the catalyst was removed by hot filtration. The filtrate was then subjected to vacuum distillation (-0.098MPa, 225℃) to remove the water and light components generated in the reaction, as well as a small amount of unreacted o-cyclohexylcyclohexanone, yielding antioxidant 4010C. The GC analysis showed a purity of 98.6% and a yield of 98.9%.

[0074] Example 4

[0075] 100g (0.55mol) of o-cyclohexylcyclohexanone, 25g (0.125mol) of 4-aminodiphenylamine, and 0.3g of 3% Pt / C catalyst were added in a single batch to a 250mL stainless steel high-pressure reactor. The reactor lid was sealed, and the reactor was purged three times with nitrogen and three times with hydrogen, respectively. The reaction temperature was controlled at 180℃, the hydrogen pressure at 0.5MPa, and the stirring speed at 800-1000rpm. Samples were periodically taken for GC analysis until the 4-aminodiphenylamine was completely converted, which took approximately 4 hours. The mixture was then cooled to 80℃, the hydrogenated liquid was transferred, and the catalyst was removed by hot filtration. The filtrate was then subjected to vacuum distillation (-0.098MPa, 230℃) to remove the water and light components generated in the reaction, as well as a small amount of unreacted o-cyclohexylcyclohexanone, yielding antioxidant 4010C. The GC analysis showed a purity of 99.5% and a yield of 98.0%.

[0076] Application examples

[0077] 1. Oxidation-Induced Time (OIT) Characteristics of Compounds

[0078] Anti-aging agent 6PPD ( Antioxidant 4010 ) and antioxidant 4010C in Example 1 ( 50 mL of 30 g / L ethyl acetate solution was prepared. 100 μL of each of these solutions was added to 3.0 g of squalene and mixed thoroughly by sonication. Using a precision balance, 20 mg of squalene without any antioxidant (blank control), 20 mg of squalene with antioxidant 6 PPD, 20 mg of squalene with antioxidant 4010, and 20 mg of squalene with antioxidant 4010C were weighed separately. These samples were then transferred to a Tzero pan and analyzed using a differential scanning calorimeter (DSC, TA Instruments, Q20). Each experiment was repeated three times, and the average value was measured. The experimental results are shown in Table 1. The specific operating procedure of the differential scanning calorimeter includes: the sample is heated in the sample cell and heated from 25°C to 190°C in a nitrogen atmosphere of 50 mL / min (heating rate of 10°C / min); after stabilizing at 190°C for 5 min, the gas flow is switched to O2 with a flow rate of 50 mL / min, and the time before the sample degradation begins is measured to obtain the OIT value.

[0079] Table 1: OIT values ​​of various antioxidants

[0080] As shown in Table 1, the OIT (Oxidation Intake) of antioxidant 4010C in this invention is superior to that of 6PPD and antioxidant 4010, indicating its excellent resistance to thermal oxidation. Furthermore, due to its larger molecular weight compared to other antioxidants, it exhibits better migration resistance in polymer materials such as rubber. In summary, antioxidant 4010C in this invention is a novel antioxidant with excellent migration resistance.

[0081] 2. Properties of the rubber composition

[0082] The mixed rubber compounds for test examples 1-4 were prepared according to the formulations shown in Table 2, and their application performance was tested. The specific steps included the following: According to the formulation shown in Table 2, prepare adhesives 1-4 using the following steps: Add natural rubber SCR5 to the internal mixer and knead for a period of time. Then add carbon black N550, aromatic oil, zinc oxide, stearic acid, and antioxidants (4010, 4010C, 6PPD, and blank), and continue kneading until the mixture is homogeneous. During kneading, the temperature should be controlled between 150°C and 160°C. Cool the entire mixture to below 100°C, then add the crosslinking system (sulfur S and accelerator NS), and knead the entire mixture. During kneading, control the temperature to not exceed 110°C. Calender the resulting rubber composition into sheets (2-3 mm thick) and vulcanize at 150°C for 15 minutes.

[0083] The sources of the materials in Table 2 are as follows: SCR5: Natural rubber SCR5 from Xishuangbanna Sinochem Rubber Co., Ltd.; N550: Cabot Corporation's N550 carbon black; Aromatic oil: Kunlun naphthenic oil KL4006 (from Kelian); Stearic acid: Stearic acid (AR), a general reagent from Shanghai Titan Technology Co., Ltd. Zinc oxide: General reagent zinc oxide (AR) from Shanghai Titan Technology Co., Ltd.; Accelerator NS: NS vulcanization accelerator from Sheng'ao Chemical Technology Co., Ltd.; Sulfur: Sublimed sulfur (AR) from Sinopharm Chemical Reagent Company; Antioxidant 4010 and 6PPD: Sheng'ao Chemical Technology Co., Ltd.

[0084] Table 2: Formulation of rubber compositions (unit: parts by mass)

[0085] According to GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber, the physical properties (tensile strength, elongation at break) of rubber compounds 1-4 were determined, and the results are shown in Table 3.

[0086] According to GB / T 3512-2014 Accelerated Aging and Heat Resistance Tests of Vulcanized Rubber or Thermoplastic Rubber in Hot Air, rubber compounds 1-4 were subjected to thermo-oxidative aging tests under the following conditions: 100℃. The test results are shown in Table 3 after 48 hours.

[0087] Table 3: Original and Aging Properties of Vulcanized Rubber

[0088] Antioxidant migration test method: The above-mentioned vulcanized rubber samples containing different antioxidants were overlapped with blank vulcanized rubber samples, and filter paper was placed on the top and bottom sides of the overlapped samples respectively. The samples were then placed in a mold of a flat vulcanizing machine. After the mold was closed, a certain pressure was applied to the overlapped samples to investigate the migration of antioxidants from the vulcanized rubber samples to the blank vulcanized rubber samples under pressure at room temperature for different times.

[0089] A certain amount of the migrated blank vulcanized rubber sample was taken and cut into uniform small particles. Soxhlet extraction was performed, and the extract was dissolved in methanol / water solution. The content of the corresponding antioxidant was measured by gas chromatography. The test results are shown in Table 4.

[0090] Table 4: Comparison of Extraction Experiments of Vulcanized Rubber Sheets with Different Antioxidants

[0091] Table 3 shows that films containing antioxidants 4010, 4010C, and 6PPD at 100℃ After 48 hours of aging, the property retention rates of compounds 1-3 were all improved compared to compound 4, with 4010C showing the highest property retention rate, indicating its excellent resistance to thermal oxidation. This is consistent with the OIT trend of the antioxidants in Table 1. Therefore, the new compound 4010C has better resistance to thermal oxidation aging.

[0092] As shown in Table 4, the extraction amount of different antioxidants at different times of vulcanized rubber sheets shows the trend of 6PPD>4010>4010C. Moreover, the migration amount of vulcanized rubber sheets with 4010C is significantly lower than that of 4010 and 6PPD. This is related to the fact that the molecular weight of antioxidant 4010C is larger than that of other antioxidants, and it has better migration resistance in polymer materials such as rubber.

[0093] In summary, the antioxidant 4010C in this invention is a novel antioxidant with excellent migration resistance.

Claims

1. Compound of Formula I: 。 2. A method for preparing the compound of formula I according to claim 1, characterized in that, The method includes: reacting 4-aminodiphenylamine and 2-cyclohexylcyclohexanone via a condensation-hydroalkylation reaction catalyzed by a noble metal catalyst to generate compound I.

3. The method as described in claim 2, characterized in that, The condensation-hydroalkylation reaction has one or more of the following characteristics: The molar ratio of 4-aminodiphenylamine to 2-cyclohexylcyclohexanone is 1:(3-10); The mass ratio of the noble metal catalyst to 4-aminodiphenylamine is (1-10):100; The temperature of the condensation-hydroalkylation reaction is 180-250℃; In the condensation-hydroalkylation reaction, the hydrogen pressure is 0.5-3 MPa; The condensation-hydroalkylation reaction takes 3-7 hours; The noble metal catalyst comprises a noble metal and a support, wherein the mass fraction of the noble metal in the noble metal catalyst is 1%-10%; the noble metal is selected from one or more of Pt, Pd, Ru and Rh; and the support is selected from one or more of carbon support, alumina, silica gel and molecular sieve.

4. The method as described in claim 2, characterized in that, The method for preparing the 2-cyclohexylcyclohexanone includes: The cyclohexanone dimer is hydrogenated to obtain 2-cyclohexylcyclohexanone; the cyclohexanone dimer is selected from one or both of 2-(1-cyclohexenyl)cyclohexanone and cyclohexylenecyclohexanone.

5. The method as described in claim 4, characterized in that, The hydrogenation reaction has one or more of the following characteristics: The hydrogenation reaction is carried out under the catalysis of a noble metal catalyst, wherein the mass ratio of the noble metal catalyst to the cyclohexanone dimer is (1.0-10):100; the noble metal catalyst comprises a noble metal and a support, wherein the mass fraction of the noble metal in the noble metal catalyst is 1-10%; the noble metal is one or more selected from Pt, Pd, Ru and Rh; the support is one or more selected from carbon support, alumina, silica gel and molecular sieve. The reaction temperature for the hydrogenation reaction is 120-180℃; In the hydrogenation reaction, the hydrogen pressure is 0.5-3 MPa; The reaction time for the hydrogenation reaction is 4-7 hours.

6. A rubber composition, characterized in that, The rubber composition comprises a diene elastomer and the compound of formula I as described in claim 1 as an antioxidant.

7. The rubber composition according to claim 6, characterized in that, The mass fraction of the compound of formula I in the rubber composition is 1-4%.

8. A rubber product, characterized in that, The rubber article comprises the rubber composition of claim 6 or 7.

9. The rubber product as described in claim 8, characterized in that, The rubber product in question is a car tire.

10. Use of the compound of formula I as described in claim 1 or 2 in improving the heat and oxygen aging resistance and / or colorfastness resistance of rubber compositions or rubber articles.

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