A diphenylpropane derivative, its preparation method and application

Abstract

The present invention discloses a diphenylpropane derivative, a preparation method thereof and an application thereof. The diphenylpropane derivative contains phenolic hydroxyl groups and amino groups, combines the advantages of amine antioxidants and phenolic antioxidants, has strong heat-oxygen aging resistance and light-oxygen aging resistance, can also improve other properties of the antioxidant, and reduces the pollution compared with amine antioxidants. It is an efficient, multifunctional, environmentally friendly and low-pollution antioxidant.

Description

Technical Field

[0001] The present invention relates to a diphenylpropane derivative, and also relates to a preparation method and an application thereof, belonging to the field of chemical engineering technology. Background Art

[0002] During the use of rubber, aging will occur, resulting in the loss of elasticity of the rubber, the decline of mechanical properties, and the shortening of service life. Adding appropriate anti-aging agents can inhibit or delay the aging process of rubber. There are many types of rubber anti-aging agents, mainly including: hindered amine type, hindered phenol type, benzimidazole type, nickel dithiocarbamate type, phosphoric acid type, and organic thiosulfonic acid type. Among them, hindered amine type anti-aging agents have become the mainstream anti-aging agents studied in recent years due to their outstanding anti-photo-oxidation aging effect. Hindered phenol type anti-aging agents have good effects in anti-thermal-oxidation aging, and they are environmentally friendly, non-toxic, less polluting, and environmentally safe anti-aging agents.

[0003] Most of the current anti-aging agents are outstanding in single performance and do not have multifunctionality. In order to improve the anti-aging effect, two or more anti-aging agents are often used together during the use of anti-aging agents. Nowadays, rubber anti-aging agents are developing towards high efficiency, environmental protection, and low cost, and studying the multifunctionalization or multifunctional integration of rubber anti-aging agents is also the development direction of rubber additives. Therefore, developing a highly efficient, multifunctional, environmentally friendly, and low-pollution anti-aging agent has become an urgent problem to be solved. Summary of the Invention

[0004] The object of the present invention is to provide a diphenylpropane derivative, which contains phenolic hydroxyl groups and amino groups at the same time. The phenolic hydroxyl groups and amino groups are compounded within the molecule, showing a synergistic effect, and having strong anti-thermal-oxidation aging and anti-photo-oxidation aging properties at the same time.

[0005] The diphenylpropane derivative of the present invention has the structural formula shown in the following formula (1):

[0006] (1)

[0008] The diphenylpropane derivative described in the present invention is 2,2-bis(4-hydroxy-3-substituted aminophenyl)propane. In the above formula (1), the substituent R can be selected from alkyl groups, phenyl groups, alkyl-substituted phenyl groups, cyclohexyl groups, alkyl-substituted cyclohexyl groups, etc.

[0009] Furthermore, when R is an alkyl group, the alkyl group can be a straight-chain alkyl group or a branched-chain alkyl group, and the number of carbon atoms of the alkyl group can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc., or any range value between them. For example, the alkyl group can be methyl, ethyl, propyl, isopropyl, butyl, pentyl, heptyl, octyl, isopentyl, isooctyl, etc.

[0010] Further, when R is a substituted phenyl group, the phenyl group may carry at least one alkyl substituent, and the alkyl group may be a C1-C10 alkyl group, such as methyl, ethyl, propyl, isopropyl, butyl, pentyl, heptyl, octyl, isopentyl, isooctyl, etc.

[0011] Further, when R is a substituted cyclohexyl group, the cyclohexyl group may carry at least one alkyl substituent, and the alkyl group may be a C1-C10 alkyl group, such as methyl, ethyl, propyl, isopropyl, butyl, pentyl, heptyl, octyl, isopentyl, isooctyl, etc.

[0012] In a specific embodiment of the present invention, the diphenylpropane derivative is selected from one of the structural formulas shown in the following table:

[0013]

[0014] The present invention also provides a preparation method of the above diphenylpropane derivative. The method uses bisphenol A and nitric acid as raw materials to first synthesize an intermediate of 2,2-bis(4-hydroxy-3-nitrophenyl)propane, and then this intermediate is subjected to a hydrogenation reaction with a ketone to obtain the final diphenylpropane derivative.

[0015] Further, the above preparation method includes the following steps:

[0016] (1) Nitration reaction of bisphenol A with nitric acid to obtain 2,2-bis(4-hydroxy-3-nitrophenyl)propane;

[0017] (2) Catalytic hydrogenation reaction of 2,2-bis(4-hydroxy-3-nitrophenyl)propane with a ketone under the action of hydrogen, a catalyst and an initiator to obtain the diphenylpropane derivative shown in formula (1).

[0018] Further, the reaction formula of the preparation method of the present invention is as follows:

[0019]

[0020] Further, in step (1), the concentration of nitric acid is 20-80 wt%, such as 20%, 30%, 40%, 50%, 60%, 70%, 80%.

[0021] Further, in step (1), the molar ratio of bisphenol A to nitric acid is 1:2-5, such as 1:2, 1:3, 1:4, 1:5.

[0022] Further, in step (1), the temperature of the nitration reaction is 20-80 °C, such as 20 °C, 25 °C, 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C.

[0023] Further, in step (1), the reaction is carried out in a solvent. As the reaction medium, any solvent that can dissolve each reactant to ensure the normal progress of the reaction is acceptable.

[0024] In a specific embodiment of the present invention, the solvent in step (1) is an alcohol solvent, such as C1-C5 alcohol, and for example, methanol, ethanol, etc.

[0025] Further, in step (1), it is preferred that nitric acid is added dropwise. First, bisphenol A is mixed with the solvent, and then the temperature is raised to the reaction temperature, and nitric acid is added dropwise for reaction.

[0026] Further, the dropping time of nitric acid is 1-2 h, such as 1 h, 1.5 h, 2 h.

[0027] Further, after the addition of nitric acid is completed, the reaction is continued under heat preservation for 1-5 h, such as 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h.

[0028] Further, in step (1), after the reaction is completed, the temperature is lowered to below 0 °C (such as -0.1 °C, -0.5 °C, -1 °C, -2 °C, -3 °C, -4 °C, -5 °C, -6 °C, -7 °C, -8 °C, -9 °C, -10 °C, and any range therebetween), followed by filtration, washing, and drying to obtain 2,2-bis(4-hydroxy-3-nitrophenyl)propane.

[0029] Further, in step (2), the ketone is the source of the substituent R in the general formula (1), and different ketones are selected according to the different structures of the products. For example, the ketone can be an alkyl ketone, a benzophenone, an alkyl-substituted benzophenone, a cyclohexanone, an alkyl-substituted cyclohexanone, etc.

[0030] In a specific embodiment of the present invention, the ketone is acetone, methyl isobutyl ketone, acetophenone, cyclohexanone.

[0031] Further, in step (2), the molar ratio of 2,2-bis(4-hydroxy-3-nitrophenyl)propane to the ketone is 1:1.2-2, such as 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2.0.

[0032] Further, in step (2), the catalyst is a catalyst commonly used in catalytic hydrogenation, such as palladium-carbon catalyst.

[0033] Further, in step (2), the dosage of the catalyst is 2%-5% of the mass of 2,2-bis(4-hydroxy-3-nitrophenyl)propane, such as 2%, 3%, 4%, 5%.

[0034] Further, in step (2), the initiator is a Lewis acid, such as aluminum chloride, copper chloride, iron chloride, zinc chloride or trifluoromethanesulfonate, preferably zinc chloride.

[0035] Further, in step (2), the dosage of the initiator is 0.5% - 2% of the mass of 2,2-bis(4-hydroxy-3-nitrophenyl)propane, such as 0.5%, 1.0%, 1.5%, 2.0%.

[0036] Further, in step (2), the reaction temperature is 60 - 90 °C, such as 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C.

[0037] Further, in step (2), the hydrogen pressure is 2 - 5 Mpa, such as 2 - 3 Mpa, 3 - 4 Mpa, 4 - 5 Mpa. The hydrogen pressure is maintained within this range during the reaction, and hydrogen can be replenished multiple times until the reaction is completed.

[0038] Further, in step (2), the reaction is carried out in a solvent. As the reaction medium, any solvent that can dissolve each reactant to ensure the normal progress of the reaction can be used.

[0039] In a specific embodiment of the present invention, the solvent in step (2) is an alcohol solvent, such as C1 - C5 alcohol, and for example, methanol, ethanol, etc.

[0040] Further, in step (2), 2,2-bis(4-hydroxy-3-nitrophenyl)propane, a ketone, a catalyst, an initiator, and a solvent are mixed, then nitrogen is introduced multiple times to expel oxygen, and finally hydrogen is introduced at the reaction temperature for the reaction. Among them, there is no special requirement for the mixing order of 2,2-bis(4-hydroxy-3-nitrophenyl)propane, the ketone, the catalyst, the initiator, and the solvent.

[0041] Further, in step (2), when the pressure in the system no longer changes, the reaction ends. After the reaction ends, the reaction solution is post-treated to obtain the 2,2-bis(4-hydroxy-3-(R-group)aminophenyl)propane product, that is, the above diphenylpropane derivative. The post-treatment steps are as follows: after the reaction ends, the solid catalyst is filtered out, the reaction solution is concentrated, then cooled for crystallization, and the precipitated crystals are filtered, washed, and dried to obtain the final product.

[0042] The diphenylpropane derivative obtained by the present invention contains phenolic hydroxyl groups and amino groups, combines the advantages of amine antioxidants and phenolic antioxidants, has strong heat-oxygen aging and light-oxygen aging resistance, can also improve other properties of the antioxidant, and reduces pollution compared with amine antioxidants. It is a highly efficient, multifunctional, environmentally friendly, and low-pollution antioxidant.

[0043] The present invention also provides the use of the above diphenylpropane derivative as an antioxidant, and the diphenylpropane derivative is preferably used as an antioxidant for rubber or rubber products. The rubber product is a product made of rubber as the sole raw material or a mixture of rubber and other raw materials, such as a tire.

[0044] The present invention also provides an antioxidant mixture, which includes the above diphenylpropane derivative.

[0045] Furthermore, in the above antioxidant mixture, other antioxidants with structures reported in the prior art can also be included, and they are combined with the diphenylpropane derivative to achieve a more comprehensive or multifunctional anti-aging effect.

[0046] The present invention also provides a rubber composition, which includes the above diphenylpropane derivative.

[0047] The present invention also provides a rubber product, which includes the above rubber composition; preferably, the rubber product is a tire.

[0048] The present invention also provides a method for improving the heat-oxygen aging resistance and / or light-oxygen aging resistance and / or flex cracking resistance of rubber and / or rubber products. The method is to add the above diphenylpropane derivative or the above antioxidant mixture to rubber and / or rubber products.

[0049] The present invention has the following beneficial effects:

[0050] 1. The diphenylpropane derivative of the present invention contains phenolic hydroxyl and amino groups, which have a synergistic effect, have better heat-oxygen aging resistance and light-oxygen aging resistance, and have a better anti-aging function.

[0051] 2. The diphenylpropane derivative of the present invention is a potential antioxidant, has excellent heat-oxygen aging resistance and light-oxygen aging resistance, and at the same time has good flex cracking resistance. It is an efficient, multifunctional, environmentally friendly and low-pollution antioxidant, and has good application prospects in rubber or rubber products.

[0052] 3. The preparation method of the diphenylpropane derivative of the present invention is simple, easy to operate, environmentally friendly, and convenient for industrial production. Description of the Drawings

[0053] Figure 1 1H-NMR spectrum of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane prepared in Example 6 1 1H-NMR spectrum.

[0054] Figure 2 1H-NMR spectrum of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane prepared in Example 613 C-NMR spectrum.

[0055] Figure 3 For 2,2-bis[4-hydroxy-3-(2-phenylethyl)aminophenyl]propane prepared in Example 13 1 H-NMR spectrum.

[0056] Figure 4 For 2,2-bis[4-hydroxy-3-(2-phenylethyl)aminophenyl]propane prepared in Example 13 13 C-NMR spectrum. Detailed implementation manners

[0057] The following describes exemplary embodiments of the present invention, including various details of the embodiments of the present invention to facilitate understanding. It should be considered merely exemplary. Therefore, those of ordinary skill in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and conciseness, descriptions of well-known functions, operations, and structures are omitted below.

[0058] Unless otherwise defined, technical and scientific terms in this specification have the same meaning as commonly understood by those skilled in the art. Although methods and materials similar or equivalent to those described herein can be used in experiments or practical applications, the materials and methods are described herein. In case of conflict, the present specification, including its definitions, shall prevail.

[0059] Unless otherwise specified, all raw materials used in the following examples are commercially available products, and the concentrations are all mass percentages.

[0060] In the following examples, the calculation formula for the yield is: mass of the product / theoretical production amount of the product × 100%.

[0061] Synthesis of 2,2-bis(4-hydroxy-3-nitrophenyl)propane

[0062] Example 1

[0063] Put 22.83 g of bisphenol A into a flask, add 100 g of ethanol and mix evenly under mechanical stirring. Start to dropwise add 126 g of 25% nitric acid at 20°C. The dropping time of nitric acid is 2 h. After the dropping is completed, continue to keep the temperature for reaction for 5 h. After the reaction, cool down to below 0°C, then filter, wash, and dry to obtain 19.89 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane. The product purity (HPLC) is 82.92%. The theoretical yield of 2,2-bis(4-hydroxy-3-nitrophenyl)propane is 31.83 g, and the yield is 62.5%.

[0064] Example 2

[0065] Put 22.83 g of bisphenol A into a flask, add 100 g of ethanol, mix evenly under mechanical stirring, heat up to 60 °C, then start to dropwise add 126 g of 25% nitric acid. The dropping time of nitric acid is 2 h. After the dropping is completed, continue to keep the temperature for reaction for 3 h. After the reaction, cool down to below 0 °C, then filter, wash, and dry to obtain 24.81 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane. The product purity (HPLC) is 87.63%. The theoretical yield of 2,2-bis(4-hydroxy-3-nitrophenyl)propane is 31.83 g, and the yield is 77.9%.

[0066] Example 3

[0067] Put 22.83 g of bisphenol A into a flask, add 100 g of ethanol, mix evenly under mechanical stirring, heat up to 60 °C, then start to dropwise add 38.77 g of 65% nitric acid. The dropping time of nitric acid is 2 h. After the dropping is completed, continue to keep the temperature for reaction for 2 h. After the reaction, cool down to below 0 °C, then filter, wash, and dry to obtain 28.40 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane. The product purity (HPLC) is 97.79%. The theoretical yield of 2,2-bis(4-hydroxy-3-nitrophenyl)propane is 31.83 g, and the yield is 89.2%.

[0068] Example 4

[0069] Put 22.83 g of bisphenol A into a flask, add 100 g of ethanol, mix evenly under mechanical stirring, heat up to 60 °C, then start to dropwise add 29.08 g of 65% nitric acid. The dropping time of nitric acid is 2 h. After the dropping is completed, continue to keep the temperature for reaction for 2 h. After the reaction, cool down to below 0 °C, then filter, wash, and dry to obtain 30.45 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane. The product purity (HPLC) is 98.72%. The theoretical yield of 2,2-bis(4-hydroxy-3-nitrophenyl)propane is 31.83 g, and the yield is 95.7%.

[0070] Example 5

[0071] Put 22.83 g of bisphenol A into a flask, add 100 g of ethanol, mix evenly under mechanical stirring, heat up to 60 °C, then start to dropwise add 29.08 g of 65% nitric acid. The dropping time of nitric acid is 1 h. After the dropping is completed, continue to keep the temperature for reaction for 2 h. After the reaction, cool down to below 0 °C, then filter, wash, and dry to obtain 30.50 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane. The product purity (HPLC) is 98.63%. The theoretical yield of 2,2-bis(4-hydroxy-3-nitrophenyl)propane is 31.83 g, and the yield is 95.8%.

[0072] Synthesis of 2,2-bis[4-hydroxy-3-(R-group)aminophenyl]propane

[0073] Example 6

[0074] 63.66 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane from Example 5 and 24.04 g of methyl isobutyl ketone were added to a high-pressure reactor. 500 g of methanol was added, and at the same time, 1.91 g of palladium-carbon catalyst and 1.27 g of aluminum chloride were added. Then, nitrogen gas was introduced into the high-pressure reactor until the pressure reached 0.5 MPa, and then the reactor was evacuated. This process was repeated 3 - 5 times. Then, the temperature of the high-temperature reactor was raised to 60 °C, and hydrogen gas was introduced. The hydrogen pressure was 2 - 3 MPa, and the hydrogenation reduction reaction began. During the reaction, when the pressure was lower than 2 MPa, hydrogen gas was filled into the reactor, and the filling pressure did not exceed 3 MPa. The reaction ended when the pressure remained unchanged. After the reaction ended, the solid catalyst was filtered out, the reaction solution was concentrated, and then it was cooled for crystallization. The precipitated crystals were filtered, washed, and dried to obtain 66.31 g of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane with a purity (HPLC) of 82.35%. Its 1 1H-NMR spectrum and 13 13C-NMR spectrum are as Figure 1 and 2 shown. The theoretical mass of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane is 85.33 g, and the yield is 77.7%.

[0075] Example 7

[0076] 63.66 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane from Example 5 and 24.04 g of methyl isobutyl ketone were added to a high-pressure reactor. 500 g of methanol was added, and at the same time, 3.18 g of palladium-carbon catalyst and 1.27 g of aluminum chloride were added. Nitrogen gas was introduced until the pressure reached 0.5 MPa, and then the reactor was evacuated. This process was repeated 3 - 5 times. The temperature of the reactor was raised to 80 °C, and hydrogen gas was introduced. The hydrogen pressure was 4 - 5 MPa. During the reaction, when the pressure was lower than 4 MPa, hydrogen gas was filled into the reactor, and the filling pressure did not exceed 5 MPa. The reaction ended when the pressure remained unchanged. After the reaction ended, the solid catalyst was filtered out, the reaction solution was concentrated, and then it was cooled for crystallization. The precipitated crystals were filtered, washed, and dried to obtain 71.05 g of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane with a purity (HPLC) of 89.75%. The theoretical mass of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane is 85.33 g, and the yield is 83.3%.

[0077] Example 8

[0078] 63.66 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 30.05 g of methyl isobutyl ketone were added to a high-pressure reactor. 500 g of methanol was added, and at the same time, 2.55 g of palladium-carbon catalyst and 1.27 g of aluminum chloride were added. Nitrogen was introduced until the pressure reached 0.5 MPa and then vacuum was pumped. This was repeated 3 - 5 times. After the reactor was heated to 80 °C, hydrogen was introduced, and the hydrogen pressure was 4 - 5 MPa. During the reaction, when the pressure was lower than 4 MPa, hydrogen was charged into the reactor, and the charged hydrogen pressure did not exceed 5 MPa. The reaction ended when the pressure remained unchanged. After the reaction ended, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled for crystallization. The precipitated crystals were filtered, washed, and dried to obtain 78.63 g of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane, with a purity (HPLC) of 95.33%. The theoretical mass of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane was 85.33 g, and the yield was 92.1%.

[0079] Example 9

[0080] 63.66 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 36.06 g of methyl isobutyl ketone were added to a high-pressure reactor. 500 g of methanol was added, and at the same time, 3.18 g of palladium-carbon catalyst and 1.27 g of zinc chloride were added. Nitrogen was introduced until the pressure reached 0.5 MPa and then vacuum was pumped. This was repeated 3 - 5 times. After the reactor was heated to 80 °C, hydrogen was introduced, and the hydrogen pressure was 4 - 5 MPa. During the reaction, when the pressure was lower than 4 MPa, hydrogen was charged into the reactor, and the charged hydrogen pressure did not exceed 5 MPa. The reaction ended when the pressure remained unchanged. After the reaction ended, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled for crystallization. The precipitated crystals were filtered, washed, and dried to obtain 77.84 g of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane, with a purity (HPLC) of 97.64%. The theoretical mass of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane was 85.33 g, and the yield was 91.2%.

[0081] Example 10

[0082] 63.66 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 36.06 g of methyl isobutyl ketone were added to a high-pressure reactor. 500 g of methanol was added, and simultaneously 3.18 g of palladium-carbon catalyst and 0.64 g of zinc chloride were added. Nitrogen was introduced until the pressure reached 0.5 MPa and then the reactor was evacuated. This was repeated 3 to 5 times. After the reactor was heated to 80 °C, hydrogen was introduced, and the hydrogen pressure was 4 - 5 MPa. During the reaction, when the pressure was lower than 4 MPa, hydrogen was charged into the reactor, and the charged hydrogen pressure did not exceed 5 MPa. The reaction ended when the pressure remained unchanged. After the reaction ended, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled for crystallization. The precipitated crystals were filtered, washed, and dried to obtain 80.67 g of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane, with a purity (HPLC) of 98.73%. The theoretical mass of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane was 85.33 g, and the yield was 94.5%.

[0083] Example 11

[0084] 63.66 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 30.05 g of methyl isobutyl ketone were added to a high-pressure reactor. 500 g of methanol was added, and simultaneously 3.18 g of palladium-carbon catalyst and 0.64 g of zinc chloride were added. Nitrogen was introduced until the pressure reached 0.5 MPa and then the reactor was evacuated. This was repeated 3 to 5 times. After the reactor was heated to 80 °C, hydrogen was introduced, and the hydrogen pressure was 4 - 5 MPa. During the reaction, when the pressure was lower than 4 MPa, hydrogen was charged into the reactor, and the charged hydrogen pressure did not exceed 5 MPa. The reaction ended when the pressure remained unchanged. After the reaction ended, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled for crystallization. The precipitated crystals were filtered, washed, and dried to obtain 80.03 g of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane, with a purity (HPLC) of 99.01%. The theoretical mass of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane was 85.33 g, and the yield was 93.8%.

[0085] Example 12

[0086] 63.66 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 17.42 g of acetone were added to a high-pressure reactor. 500 g of methanol was added, and at the same time, 3.18 g of palladium-carbon catalyst and 0.64 g of zinc chloride were added. Nitrogen was introduced until the pressure reached 0.5 MPa, and then the reactor was evacuated. This process was repeated 3 - 5 times. After the reactor was heated to 80 °C, hydrogen was introduced, and the hydrogen pressure was 4 - 5 MPa. During the reaction, when the pressure was lower than 4 MPa, hydrogen was filled into the reactor, and the filled hydrogen pressure did not exceed 5 MPa. The reaction ended when the pressure remained unchanged. After the reaction ended, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled for crystallization. The precipitated crystals were filtered, washed, and dried to obtain 65.23 g of 2,2-bis[4-hydroxy-3-(isopropyl)aminophenyl]propane with a purity (HPLC) of 98.66%. The theoretical mass of 2,2-bis[4-hydroxy-3-(isopropyl)aminophenyl]propane was 68.50 g, and the yield was 95.2%.

[0087] Example 13

[0088] 63.66 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 36.05 g of acetophenone were added to a high-pressure reactor. 500 g of methanol was added, and at the same time, 3.18 g of palladium-carbon catalyst and 0.64 g of zinc chloride were added. Nitrogen was introduced until the pressure reached 0.5 MPa, and then the reactor was evacuated. This process was repeated 3 - 5 times. After the reactor was heated to 80 °C, hydrogen was introduced, and the hydrogen pressure was 4 - 5 MPa. During the reaction, when the pressure was lower than 4 MPa, hydrogen was filled into the reactor, and the filled hydrogen pressure did not exceed 5 MPa. The reaction ended when the pressure remained unchanged. After the reaction ended, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled for crystallization. The precipitated crystals were filtered, washed, and dried to obtain 86.97 g of 2,2-bis[4-hydroxy-3-(2-phenylethyl)aminophenyl]propane with a purity (HPLC) of 98.24%, and its 1 1H-NMR spectrum and 13 13C-NMR spectrum are as Figure 3 and 4 shown. The theoretical mass of 2,2-bis[4-hydroxy-3-(2-phenylethyl)aminophenyl]propane was 93.33 g, and the yield was 93.2%.

[0089] Comparative Example

[0090] 63.66 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 500 g of methanol were added to an autoclave. Meanwhile, 3.18 g of palladium-carbon catalyst was added. Nitrogen was introduced until the pressure reached 0.5 MPa and then the system was evacuated, and this was repeated 3 - 5 times. After the autoclave was heated to 80 °C, hydrogen was introduced, and the hydrogen pressure was 4 - 5 MPa. During the reaction, when the pressure was lower than 4 MPa, hydrogen was charged into the autoclave, and the charged hydrogen pressure did not exceed 5 MPa. The reaction ended when the pressure remained unchanged. After the reaction ended, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled for crystallization. The precipitated crystals were filtered, washed, and dried to obtain 47.84 g of 2,2-bis(4-hydroxy-3-aminophenyl)propane with a purity (HPLC) of 98.35%. The theoretical amount of 2,2-bis(4-hydroxy-3-aminophenyl)propane was 51.66 g, and the yield was 92.6%.

[0091] Performance verification

[0092] 2,2-Bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane (new multifunctional antioxidant 1) synthesized in Example 10, 2,2-bis[4-hydroxy-3-(isopropyl)aminophenyl]propane (new multifunctional antioxidant 2) synthesized in Example 12, 2,2-bis[4-hydroxy-3-(2-phenylethyl)aminophenyl]propane (new antioxidant 3) synthesized in Example 13, 2,2-bis[4-hydroxy-3-aminophenyl]propane (comparative antioxidant) synthesized in Comparative Example 1, antioxidant 4030 (purchased from Hubei Yongkuo Technology Co., Ltd.), and light stabilizer 2246 (also known as antioxidant 2246, purchased from Shanghai Macklin Biochemical Co., Ltd.) were used for application comparison experiments.

[0093] 1. Vulcanized rubber sample formula (parts by weight): 100 parts of natural rubber NR, 50 parts of carbon black N220, 3.5 parts of pine tar, 5.0 parts of zinc oxide, 3.0 parts of stearic acid, 0.6 part of accelerator M, 0.6 part of sulfur, and 3.0 parts of antioxidant. The antioxidant was the above-mentioned antioxidant 4030, light stabilizer 2246, new multifunctional antioxidant 1, new multifunctional antioxidant 2, synthesized new multifunctional antioxidant 3, comparative antioxidant, and a mixture of antioxidant 4030 and light stabilizer 2246 with a mass ratio of 1:1. Meanwhile, the sample without antioxidant was used as a blank control.

[0094] 2. Processing technology of the rubber compound: The rotor speed of the first-stage mixing was 40 r·min-1. Natural rubber NR was first plasticized for 1 min, and then carbon black N220, pine tar, zinc oxide, stearic acid, and antioxidant were added. The pressure weight was pressed for 35 s and lifted for 10 s, then pressed for 45 s and lifted for 10 s, and then discharged (145 °C). The rotor speed of the second-stage mixing was 48 r·min-1. The first-stage mixed rubber, sulfur, and accelerator M were added. The pressure weight was pressed for 80 s and lifted for 10 s, then pressed for 55 s, and then discharged (110 °C).

[0095] 3. Performance Comparison

[0096] 3.1 Mooney Viscosity

[0097] The efficiency of anti - aging agents is measured by the hot - air aging test method. The anti - aging performance of anti - aging agents is characterized by the Mooney viscosity of the samples after the aging test. The smaller the change in Mooney viscosity, the better the anti - thermal - oxidation aging performance. Conversely, the larger the Mooney viscosity, the worse the anti - thermal - oxidation aging performance. The Mooney viscosity is tested according to the standard of GB / T 1232 - 2000.

[0098] Seven kinds of specimens are placed in an aging oven for hot - air aging, and the Mooney viscosity (M 100℃ 1+4 ) of the samples at 100 °C at different aging times is measured. The test results are shown in Table 1.

[0099] As can be seen from Table 1, among the seven formulations, after the vulcanizates are thermally oxidized by hot air for the same time, the increasing amplitude of Mooney viscosity gradually decreases. The increasing amplitudes of Mooney viscosity of the vulcanizates of the three new multifunctional anti - aging agents synthesized in Examples 10, 12, and 13 are smaller than those of the vulcanizates added with anti - aging agent 4030, light stabilizer 2246, the anti - aging agent of Comparative Example 1, and the vulcanizate without adding any anti - aging agent, indicating that the new multifunctional anti - aging agents of the present invention have stronger anti - thermal - oxidation aging performance. Among them, the best anti - thermal - oxidation aging performance is shown by the new multifunctional anti - aging agent 1.

[0100] 3.2 Flexing Crack Resistance Effect under Different Formulations

[0101] The seven numbered samples are tested for the flexing crack resistance of vulcanizates according to the standard of GB13934 - 1992. The test results are shown in Table 2.

[0102]

[0103] As can be seen from Table 2, in terms of crack testing, the flexing crack resistance effects of the three new multifunctional anti - aging agents of the present invention are better than those of anti - aging agent 4030, light stabilizer 2246, and the anti - aging agent of Comparative Example 1. Among them, the best flexing crack resistance performance is shown by the new multifunctional anti - aging agent 1.

[0104] 3.3 Ultraviolet Light Aging Performance Test

[0105] Six natural rubber vulcanizate samples are placed in an ultraviolet light box and aged for 120 h at a temperature of 60 °C. By comparing the changes in tensile strength and elongation at break before and after aging, the ultraviolet light aging resistance performance of each anti - aging agent is judged. The test results are shown in Table 3 below.

[0106]

[0107] As can be seen from the data in the above table, under the conditions of an aging temperature of 60 °C and an aging time of 120 h, the tensile strength and elongation at break of the NR vulcanizates added with novel antioxidants 1, 2, and 3 and the NR vulcanizate added with light stabilizer 2246 both decreased slightly. However, the tensile strength of the NR vulcanizate added with antioxidant 4030 decreased significantly, while the elongation at break increased. This may be due to the reduction of the crosslinking density of the vulcanizate caused by ultraviolet aging. It can be seen from this that the ultraviolet light aging resistance performance of the novel antioxidant of the present invention is not much different from that of light stabilizer 2246.

[0108] In summary, 2,2-bis【4-hydroxy-3-(R-group) aminophenyl】propane synthesized in the present invention has both strong thermal-oxidative aging resistance and photo-oxidative aging resistance, good flex cracking resistance, and less pollution compared with single amine antioxidants. It is an efficient, multifunctional, environmentally friendly, and low-pollution antioxidant.

Claims

1. A method for preparing 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane, characterized in that The following steps are involved: (1) 22.83 g of bisphenol A is put into a flask, 100 g of ethanol is added and mixed evenly under mechanical stirring, and 29.08 g of 65% nitric acid is added dropwise after the temperature is raised to 60° C. The nitric acid is added dropwise for 1 hour or 2 hours. After the addition is completed, the temperature is kept warm for reaction for 2 hours. After the reaction, the temperature is lowered to below 0° C., filtered, washed, and dried to obtain 2,2-bis(4-hydroxy-3-nitrophenyl)propane; (2) 63.66 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane and 36.06 g of methyl isobutyl ketone were added to a high-pressure reactor, and 500 g of methanol and 3.18 g of palladium carbon catalyst and 0.64 g of zinc chloride were added simultaneously. Nitrogen was introduced to 0.5 MPa and then vacuum was evacuated. This was repeated 3 to 5 times. The reactor was heated to 80° C. and hydrogen was introduced at a hydrogen pressure of 4 to 5 MPa. During the reaction, the pressure was lower than 4 MPa and hydrogen was introduced into the reactor. The hydrogen pressure did not exceed 5 MPa. The reaction was terminated when the pressure remained constant. After the reaction was completed, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled for crystallization. The precipitated crystals were filtered, washed, and dried to obtain 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane.

2. A method for preparing 2,2-bis[4-hydroxy-3-(2-phenylethyl)aminophenyl]propane, characterized in that The following steps are involved: (1) 22.83 g of bisphenol A is put into a flask, 100 g of ethanol is added and mixed evenly under mechanical stirring, and 29.08 g of 65% nitric acid is added dropwise after the temperature is raised to 60° C. The nitric acid is added dropwise for 1 hour or 2 hours. After the addition is completed, the temperature is kept warm for reaction for 2 hours. After the reaction, the temperature is lowered to below 0° C., filtered, washed, and dried to obtain 2,2-bis(4-hydroxy-3-nitrophenyl)propane; (2) 63.66 g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane and 36.05 g of acetophenone were added to a high-pressure reactor, and 500 g of methanol was added, and 3.18 g of palladium carbon catalyst and 0.64 g of zinc chloride were added at the same time. Nitrogen was introduced to 0.5 MPa and then vacuum was evacuated. This was repeated 3 to 5 times. The reactor was heated to 80°C and then hydrogen was introduced. The hydrogen pressure was 4-5 MPa. During the reaction, when the pressure was lower than 4 MPa, hydrogen was introduced into the reactor. The hydrogen pressure did not exceed 5 MPa. The reaction was terminated when the pressure remained constant. After the reaction was completed, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled for crystallization. The precipitated crystals were filtered, washed, and dried to obtain 2,2-bis[4-hydroxy-3-(2-phenylethyl)aminophenyl]propane.

3. A method for improving the light-oxidation aging resistance and / or flex cracking resistance of rubber and / or rubber products, characterized in that: Add 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane prepared by the preparation method according to claim 1 or 2,2-bis[4-hydroxy-3-(2-phenylethyl)aminophenyl]propane prepared by the preparation method according to claim 2 to rubber and / or rubber products.

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