Diphenylpropane derivative as well as preparation method and application thereof

Abstract

The invention discloses a diphenylpropane derivative and a preparation method and application thereof.The diphenylpropane derivative contains phenolic hydroxyl groups and amino groups, integrates the advantages of amino anti-aging agents and phenolic anti-aging agents, has high thermo-oxidative aging resistance and photo-oxidative aging resistance, can improve other properties of the anti-aging agents, and has a good application prospect. And compared with amine anti-aging agents, pollution is reduced, and the anti-aging agent is efficient, multifunctional, environment-friendly and low in pollution.

Description

Technical Field

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

[0002] Rubber will age during use, causing it to lose elasticity, deteriorate mechanical properties, and shorten its service life. Adding appropriate antioxidants can inhibit or delay the aging process of rubber. There are many types of rubber antioxidants, mainly divided into: hindered amines, hindered phenols, benzimidazoles, nickel dithiocarbamates, phosphoric acids, and organic thioacids. Among them, hindered amine antioxidants have become the mainstream antioxidants studied in recent years due to their outstanding anti-photooxidative aging effects. Hindered phenol antioxidants have good effects in resisting thermal oxidative aging, and they are environmentally friendly and are non-toxic, less polluting, and environmentally safe antioxidants.

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

[0004] The purpose of the present invention is to provide a diphenylpropane derivative, which contains phenolic hydroxyl group and amino group at the same time. The phenolic hydroxyl group and amino group are compounded in the molecule to show a synergistic effect and have strong resistance to thermal oxidative aging and light oxidative aging.

[0005] The diphenylpropane derivative of the present invention has the structural formula shown in the following formula (1): (1) The diphenylpropane derivative of 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, phenyl, alkyl-substituted phenyl, cyclohexyl, alkyl-substituted cyclohexyl, etc.

[0006] Further, when R is an alkyl group, the alkyl group may be a straight chain alkyl group or a branched chain alkyl group, and the number of carbon atoms in the alkyl group may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc., or any range therebetween. For example, the alkyl group may be a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, a heptyl group, an octyl group, an isopentyl group, an isooctyl group, etc.

[0007] Furthermore, when R is a substituted phenyl group, the phenyl group may have at least one alkyl substituent, and the alkyl group may be a C1-C10 alkyl group, for example, methyl, ethyl, propyl, isopropyl, butyl, pentyl, heptyl, octyl, isopentyl, isooctyl, etc.

[0008] Furthermore, when R is a substituted cyclohexyl group, the cyclohexyl group may have at least one alkyl substituent, and the alkyl group may be a C1-C10 alkyl group, for example, methyl, ethyl, propyl, isopropyl, butyl, pentyl, heptyl, octyl, isopentyl, isooctyl, etc.

[0009] In a specific embodiment of the present invention, the diphenylpropane derivative is selected from one of the structural formulas shown in the following table: The present invention also provides a method for preparing the above-mentioned diphenylpropane derivatives. The method uses bisphenol A and nitric acid as raw materials to first synthesize a 2,2-bis(4-hydroxy-3-nitrophenyl)propane intermediate, and then the intermediate is hydrogenated with a ketone to obtain the final diphenylpropane derivative.

[0010] Furthermore, the above preparation method comprises the following steps: (1) Bisphenol A is nitrated with nitric acid to obtain 2,2-bis(4-hydroxy-3-nitrophenyl)propane; (2) 2,2-Bis(4-hydroxy-3-nitrophenyl)propane and ketone are subjected to catalytic hydrogenation reaction in the presence of hydrogen, a catalyst and an initiator to obtain a diphenylpropane derivative represented by formula (1).

[0011] Further, the reaction formula of the preparation method of the present invention is as follows: Furthermore, in step (1), the concentration of nitric acid is 20-80 wt %, for example, 20%, 30%, 40%, 50%, 60%, 70%, 80%.

[0012] Furthermore, in step (1), the molar ratio of bisphenol A to nitric acid is 1:2-5, for example, 1:2, 1:3, 1:4, 1:5.

[0013] Furthermore, in step (1), the temperature of the nitration reaction is 20-80°C, for example, 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.

[0014] Furthermore, in step (1), the reaction is carried out in a solvent, and the solvent used as the reaction medium can be any solvent that can dissolve the reactants and ensure the normal progress of the reaction.

[0015] In a specific embodiment of the present invention, the solvent in step (1) is an alcohol solvent, such as C1-C5 alcohol, methanol, ethanol, etc.

[0016] Furthermore, in step (1), nitric acid is preferably added dropwise, wherein bisphenol A is first mixed with a solvent, and then the temperature is raised to the reaction temperature and nitric acid is added dropwise to react.

[0017] Furthermore, the dropping time of nitric acid is 1 to 2 hours, for example, 1 hour, 1.5 hours, or 2 hours.

[0018] Further, after the nitric acid is dripped, the reaction is kept warm for 1 to 5 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, and 5 hours.

[0019] Furthermore, in step (1), after the reaction is completed, the temperature is lowered to below 0°C (e.g., -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), filtered, washed, and dried to obtain 2,2-bis(4-hydroxy-3-nitrophenyl)propane.

[0020] Furthermore, in step (2), the ketone is the source of the substituent R in the general formula (1), and different ketones are selected according to different product structures. For example, the ketone can be an alkyl ketone, a benzophenone, an alkyl-substituted benzophenone, a cyclohexanone, an alkyl-substituted cyclohexanone, etc.

[0021] In a specific embodiment of the present invention, the ketone is acetone, methyl isobutyl ketone, acetophenone, or cyclohexanone.

[0022] Furthermore, in step (2), the molar ratio of 2,2-bis(4-hydroxy-3-nitrophenyl)propane to ketone is 1:1.2-2, for example, 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.

[0023] Furthermore, in step (2), the catalyst is a catalyst commonly used in catalytic hydrogenation, such as a palladium-carbon catalyst.

[0024] Furthermore, in step (2), the amount of catalyst used is 2% to 5% by mass of 2,2-bis(4-hydroxy-3-nitrophenyl)propane, for example, 2%, 3%, 4%, or 5%.

[0025] Furthermore, in step (2), the initiator is a Lewis acid, such as aluminum chloride, copper chloride, iron chloride, zinc chloride or trifluoromethanesulfonate, preferably zinc chloride.

[0026] Furthermore, in step (2), the amount of initiator used is 0.5% to 2% of the mass of 2,2-bis(4-hydroxy-3-nitrophenyl)propane, for example, 0.5%, 1.0%, 1.5%, or 2.0%.

[0027] Furthermore, in step (2), the reaction temperature is 60-90°C, for example, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C.

[0028] Furthermore, in step (2), the hydrogen pressure is 2-5 MPa, for example, 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.

[0029] Furthermore, in step (2), the reaction is carried out in a solvent, and the solvent used as the reaction medium can be any solvent that can dissolve the reactants and ensure the normal progress of the reaction.

[0030] In a specific embodiment of the present invention, the solvent in step (2) is an alcohol solvent, such as C1-C5 alcohol, methanol, ethanol, etc.

[0031] Furthermore, in step (2), 2,2-bis(4-hydroxy-3-nitrophenyl)propane, ketone, catalyst, initiator, and solvent are mixed, and then nitrogen is introduced multiple times to expel oxygen, and finally the temperature is raised to the reaction temperature and hydrogen is introduced to react. There is no special requirement for the mixing order of 2,2-bis(4-hydroxy-3-nitrophenyl)propane, ketone, catalyst, initiator, and solvent.

[0032] Furthermore, in step (2), the reaction is completed when the pressure in the system no longer changes. After the reaction is completed, the reaction solution is post-treated to obtain the 2,2-bis(4-hydroxy-3-(R-)aminophenyl)propane product, i.e., the above-mentioned diphenylpropane derivative. The post-treatment step is: after the reaction is completed, the solid catalyst is filtered out, the reaction solution is concentrated, and then cooled for crystallization, and the precipitated crystals are filtered, washed, and dried to obtain the final product.

[0033] The diphenylpropane derivative obtained by the invention contains phenolic hydroxyl group and amino group, combines the advantages of amino antioxidant and phenolic antioxidant, has strong resistance to heat-oxidative aging and light-oxidative aging, can improve other properties of the antioxidant, and has less pollution compared with amine antioxidant, so it is a highly efficient, multifunctional, environmentally friendly and low-pollution antioxidant.

[0034] The present invention also provides the use of the diphenylpropane derivative as an antioxidant, and the diphenylpropane derivative is preferably used as an antioxidant for rubber or rubber products. The rubber products are products made from rubber as the only raw material or from a mixture of rubber and other raw materials, such as tires.

[0035] The present invention also provides an antioxidant mixture, which comprises the above diphenylpropane derivative.

[0036] Furthermore, the antioxidant mixture may also include antioxidants of other structures reported in the prior art, which can be combined with diphenylpropane derivatives to achieve a more comprehensive or multifunctional anti-aging effect.

[0037] The present invention also provides a rubber composition, which comprises the diphenylpropane derivative.

[0038] The present invention also provides a rubber product, which comprises the rubber composition; preferably, the rubber product is a tire.

[0039] The present invention also provides a method for improving the heat-oxidative aging resistance and / or light-oxidative aging resistance and / or flex cracking resistance of rubber and / or rubber products, which comprises adding the above-mentioned diphenylpropane derivative or the above-mentioned antioxidant mixture to the rubber and / or rubber products.

[0040] The present invention has the following beneficial effects: 1. The diphenylpropane derivatives of the present invention contain phenolic hydroxyl groups and amino groups, which have a synergistic effect, have better resistance to heat-oxidative aging and light-oxidative aging, and have better anti-aging function.

[0041] 2. The diphenylpropane derivative of the present invention is a potential antioxidant with excellent resistance to heat-oxidative aging and light-oxidative aging, as well as good resistance to flex cracking. It is a highly efficient, multifunctional, environmentally friendly, low-pollution antioxidant with good application prospects in rubber or rubber products.

[0042] 3. The preparation method of the diphenylpropane derivative of the present invention is simple, easy to operate, green and environmentally friendly, and convenient for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane prepared in Example 6 1 H-NMR spectrum.

[0044] Figure 2 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane prepared in Example 6 13 C-NMR spectrum.

[0045] Figure 3 2,2-bis[4-hydroxy-3-(2-phenylethyl)aminophenyl]propane prepared in Example 13 1 H-NMR spectrum.

[0046] Figure 4 2,2-bis[4-hydroxy-3-(2-phenylethyl)aminophenyl]propane prepared in Example 13 13 C-NMR spectrum. DETAILED DESCRIPTION

[0047] The following is a description of exemplary embodiments of the present invention, including various details of the embodiments of the present invention to aid understanding, which should be considered as merely exemplary. Therefore, it should be appreciated by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Likewise, for clarity and simplicity, descriptions of well-known functions, operations, and structures are omitted in the following description.

[0048] Unless otherwise defined, the technical and scientific terms in this specification have the same meaning as those commonly understood by those skilled in the art. Although similar or identical methods and materials as those described herein may be used in experiments or practical applications, the present invention still describes the materials and methods below. In the event of a conflict, the present specification, including definitions, shall prevail.

[0049] Unless otherwise specified, all raw materials used in the following examples are commercially available products, and the concentrations are all mass percentage concentrations.

[0050] In the following examples, the yield is calculated as follows: mass of product / theoretical yield of product×100%.

[0051] Synthesis of 2,2-bis(4-hydroxy-3-nitrophenyl)propane Example 1 22.83g of bisphenol A was put into a flask, 100g of ethanol was added and mixed evenly under mechanical stirring, 126g of 25% nitric acid was added dropwise at 20°C, the nitric acid addition time was 2h, and the reaction was continued for 5h after the addition was completed. After the reaction, the temperature was lowered to below 0°C, filtered, washed and dried to obtain 19.89g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane, and the product purity (HPLC) was 82.92%. The theoretical 2,2-bis(4-hydroxy-3-nitrophenyl)propane yield was 31.83g, and the yield was 62.5%.

[0052] Example 2 22.83g of bisphenol A was put into a flask, and 100g of ethanol was added and mixed evenly under mechanical stirring. After the temperature was raised to 60°C, 126g of 25% nitric acid was added dropwise. The nitric acid addition time was 2h. After the addition was completed, the reaction was continued for 3h. After the reaction, the temperature was lowered to below 0°C, and then filtered, washed, and dried to obtain 24.81g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane. The product purity (HPLC) was 87.63%. The theoretical 2,2-bis(4-hydroxy-3-nitrophenyl)propane yield was 31.83g, and the yield was 77.9%.

[0053] Example 3 22.83g of bisphenol A was put into a flask, and 100g of ethanol was added and mixed evenly under mechanical stirring. After the temperature was raised to 60°C, 38.77g of 65% nitric acid was added dropwise. The nitric acid addition time was 2h. After the addition was completed, the reaction was continued for 2h. After the reaction, the temperature was lowered to below 0°C, and then filtered, washed, and dried to obtain 28.40g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane. The product purity (HPLC) was 97.79%. The theoretical 2,2-bis(4-hydroxy-3-nitrophenyl)propane yield was 31.83g, and the yield was 89.2%.

[0054] Example 4 22.83g of bisphenol A was put into a flask, and 100g of ethanol was added and mixed evenly under mechanical stirring. After the temperature was raised to 60°C, 29.08g of 65% nitric acid was added dropwise. The nitric acid addition time was 2h. After the addition was completed, the reaction was continued for 2h. After the reaction, the temperature was lowered to below 0°C, filtered, washed, and dried to obtain 30.45g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane. The product purity (HPLC) was 98.72%. The theoretical yield of 2,2-bis(4-hydroxy-3-nitrophenyl)propane was 31.83g, and the yield was 95.7%.

[0055] Example 5 22.83g of bisphenol A was put into a flask, and 100g of ethanol was added and mixed evenly under mechanical stirring. After the temperature was raised to 60°C, 29.08g of 65% nitric acid was added dropwise. The nitric acid addition time was 1h. After the addition was completed, the reaction was continued for 2h. After the reaction, the temperature was lowered to below 0°C, filtered, washed, and dried to obtain 30.50g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane. The product purity (HPLC) was 98.63%. The theoretical yield of 2,2-bis(4-hydroxy-3-nitrophenyl)propane was 31.83g, and the yield was 95.8%.

[0056] Synthesis of 2,2-bis[4-hydroxy-3-(R-yl)aminophenyl]propane Example 6 63.66g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 24.04g of methyl isobutyl ketone were added to a high-pressure reactor, 500g of methanol was added, and 1.91g of palladium carbon catalyst and 1.27g of aluminum chloride were added at the same time. Then, nitrogen was passed into the high-pressure reactor to 0.5MPa and then vacuumed. This was repeated 3 to 5 times. Then, the high-temperature reactor was heated to 60°C and hydrogen was passed in. The hydrogen pressure was 2-3MPa. The hydrogenation reduction reaction was started. During the reaction, the pressure was lower than 2MPa, and hydrogen was filled into the reactor. The filling pressure did not exceed 3MPa. The reaction was terminated when the pressure remained unchanged. After the reaction was completed, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled and crystallized. The precipitated crystals were filtered, washed, and dried to obtain 66.31g of 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane with a purity (HPLC) of 82.35%. 1 H-NMR spectra and 13 C-NMR spectrum Figure 1 and 2 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%.

[0057] Example 7 63.66g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 24.04g of methyl isobutyl ketone were added to a high-pressure reactor, 500g of methanol was added, and 3.18g of palladium carbon catalyst and 1.27g of aluminum chloride were added at the same time. Nitrogen was passed to 0.5MPa and then vacuumed. This was repeated 3 to 5 times. After the reactor was heated to 80°C, hydrogen was passed in. The hydrogen pressure was 4-5MPa. During the reaction, the pressure was lower than 4MPa and then hydrogen was filled into the reactor. The hydrogen pressure did not exceed 5MPa. The reaction was terminated when the pressure remained unchanged. After the reaction was completed, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled and crystallized. The precipitated crystals were filtered, washed, and dried to obtain 71.05g 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%.

[0058] Example 8 63.66g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 30.05g of methyl isobutyl ketone were added to a high-pressure reactor, 500g of methanol and 2.55g of palladium carbon catalyst and 1.27g of aluminum chloride were added at the same time, nitrogen was passed to 0.5MPa and then vacuumed, repeated 3 to 5 times, hydrogen was passed into the reactor after the temperature was raised to 80°C, and the hydrogen pressure was 4-5MPa. During the reaction, the pressure was lower than 4MPa and then hydrogen was filled into the reactor. The hydrogen pressure did not exceed 5MPa, and the reaction was terminated when the pressure remained unchanged. After the reaction was completed, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled and crystallized. The precipitated crystals were filtered, washed, and dried to obtain 78.63g 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 is 85.33 g, and the yield is 92.1%.

[0059] Example 9 63.66g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 36.06g of methyl isobutyl ketone were added to a high-pressure reactor, 500g of methanol and 3.18g of palladium carbon catalyst and 1.27g of zinc chloride were added at the same time, nitrogen was passed to 0.5MPa and then vacuumed, repeated 3 to 5 times, hydrogen was passed into the reactor after the temperature was raised to 80°C, and the hydrogen pressure was 4-5MPa. During the reaction, the pressure was lower than 4MPa and then hydrogen was filled into the reactor. The hydrogen pressure did not exceed 5MPa, and the reaction was terminated when the pressure remained unchanged. After the reaction was completed, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled and crystallized. The precipitated crystals were filtered, washed, and dried to obtain 77.84g 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 is 85.33 g, and the yield is 91.2%.

[0060] Example 10 63.66g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 36.06g of methyl isobutyl ketone were added to a high-pressure reactor, 500g of methanol was added, and 3.18g of palladium carbon catalyst and 0.64g of zinc chloride were added at the same time. Nitrogen was passed to 0.5MPa and then vacuumed. This was repeated 3 to 5 times. After the reactor was heated to 80°C, hydrogen was passed in. The hydrogen pressure was 4-5MPa. During the reaction, the pressure was lower than 4MPa and then hydrogen was filled into the reactor. The hydrogen pressure did not exceed 5MPa. The reaction was terminated when the pressure remained unchanged. After the reaction was completed, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled and crystallized. The precipitated crystals were filtered, washed, and dried to obtain 80.67g 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 is 85.33 g, and the yield is 94.5%.

[0061] Embodiment 11 63.66g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 30.05g of methyl isobutyl ketone were added to a high-pressure reactor, 500g of methanol and 3.18g of palladium carbon catalyst and 0.64g of zinc chloride were added at the same time, nitrogen was passed to 0.5MPa and then vacuumed, repeated 3 to 5 times, hydrogen was passed into the reactor after the temperature was raised to 80°C, and the hydrogen pressure was 4-5MPa. During the reaction, the pressure was lower than 4MPa and then hydrogen was filled into the reactor. The hydrogen pressure did not exceed 5MPa, and the reaction was terminated when the pressure remained unchanged. After the reaction was completed, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled and crystallized. The precipitated crystals were filtered, washed, and dried to obtain 80.03g 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 is 85.33 g, and the yield is 93.8%.

[0062] Example 12 63.66g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 17.42g of acetone were added to a high-pressure reactor, 500g of methanol was added, and 3.18g of palladium carbon catalyst and 0.64g of zinc chloride were added at the same time. Nitrogen was passed to 0.5MPa and then vacuumed. This was repeated 3 to 5 times. After the reactor was heated to 80°C, hydrogen was passed in. The hydrogen pressure was 4-5MPa. During the reaction, the pressure was lower than 4MPa and then hydrogen was filled into the reactor. The hydrogen pressure did not exceed 5MPa. The reaction was terminated when the pressure remained unchanged. After the reaction was completed, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled and crystallized. The precipitated crystals were filtered, washed, and dried to obtain 65.23g 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 is 68.50 g, and the yield is 95.2%.

[0063] Embodiment 13 63.66g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 36.05g of acetophenone were added to a high-pressure reactor, 500g of methanol and 3.18g of palladium-carbon catalyst and 0.64g of zinc chloride were added at the same time, nitrogen was passed to 0.5MPa and then vacuumed, repeated 3 to 5 times, hydrogen was passed into the reactor after the temperature was raised to 80°C, and the hydrogen pressure was 4-5MPa. During the reaction, the pressure was lower than 4MPa, and hydrogen was filled into the reactor. The hydrogen pressure did not exceed 5MPa, and the reaction was terminated when the pressure remained unchanged. 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 86.97g of 2,2-bis[4-hydroxy-3-(2-phenylethyl)aminophenyl]propane with a purity (HPLC) of 98.24%. 1 H-NMR spectra and 13 C-NMR spectrum Figure 3 and 4 The theoretical mass of 2,2-bis[4-hydroxy-3-(2-phenylethyl)aminophenyl]propane is 93.33 g, and the yield is 93.2%.

[0064] Comparative Example 63.66g of 2,2-bis(4-hydroxy-3-nitrophenyl)propane of Example 5 and 500g of methanol were added to a high-pressure reactor, and 3.18g of palladium-carbon catalyst was added at the same time. Nitrogen was passed to 0.5MPa and then vacuumed. This was repeated 3 to 5 times. After the reactor was heated to 80°C, hydrogen was passed in, and the hydrogen pressure was 4-5MPa. During the reaction, the pressure was lower than 4MPa, and hydrogen was filled into the reactor. The hydrogen pressure did not exceed 5MPa. The reaction was terminated when the pressure remained unchanged. After the reaction was completed, the solid catalyst was filtered out, the reaction solution was concentrated, and then cooled and crystallized. The precipitated crystals were filtered, washed, and dried to obtain 47.84g of 2,2-bis(4-hydroxy-3-aminophenyl)propane, with a purity (HPLC) of 98.35%. Theoretical 2,2-bis(4-hydroxy-3-aminophenyl)propane was 51.66g, and the yield was 92.6%.

[0065] Performance Verification The 2,2-bis[4-hydroxy-3-(1,3-dimethylbutyl)aminophenyl]propane synthesized in Example 10 (new multifunctional antioxidant 1), the 2,2-bis[4-hydroxy-3-(isopropyl)aminophenyl]propane synthesized in Example 12 (new multifunctional antioxidant 2), the 2,2-bis[4-hydroxy-3-(2-phenylethyl)aminophenyl]propane synthesized in Example 13 (new antioxidant 3), the 2,2-bis[4-hydroxy-3-aminophenyl]propane synthesized in Comparative Example 1 (comparative antioxidant), antioxidant 4030 (purchased from Hubei Yongkuo Technology Co., Ltd.), and light stabilizer 2246 (also known as antioxidant 2246, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) were subjected to application comparison experiments.

[0066] 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 parts of accelerator M, 0.6 parts of sulfur, and 3.0 parts of antioxidant. The antioxidants are the above-mentioned antioxidant 4030, light stabilizer 2246, new multifunctional antioxidant 1, new multifunctional antioxidant 2, synthetic new multifunctional antioxidant 3, comparative antioxidant, and a mixture of antioxidant 4030 and light stabilizer 2246 in a mass ratio of 1:1. At the same time, the sample without antioxidant is used as a blank control.

[0067] 2. Rubber processing technology: The rotor speed of the first stage mixing is 40r·min-1. Natural rubber NR is first plasticized for 1min, then carbon black N220, pine tar, zinc oxide, stearic acid, and antioxidant are added, the pressing roller is pressed for 35s and raised for 10s, the pressing roller is pressed for 45s, the pressing roller is raised for 10s, and the rubber is discharged (145℃). The rotor speed of the second stage mixing is 48r·min-1, and the first stage mixing rubber, sulfur, and accelerator M are mixed, the pressing roller is pressed for 80s and raised for 10s, the pressing roller is pressed for 55s, and the rubber is discharged (110℃).

[0068] 3. Performance comparison 3.1 Mooney viscosity The hot air aging test method is used to measure the efficiency of the antioxidant. The Mooney viscosity of the sample after the aging test is used to characterize the anti-aging performance of the antioxidant. The smaller the change in Mooney viscosity, the better the anti-thermal oxidative aging performance. Conversely, the larger the Mooney viscosity, the worse the anti-thermal oxidative aging performance. Mooney viscosity is tested according to GB / T 1232-2000 standard.

[0069] The seven samples were placed in an aging box for hot air aging, and the Mooney viscosity (M) of the samples at 100°C was measured at different aging times. 100℃ 1+4 ), the test results are shown in Table 1.

[0070] As can be seen from Table 1, in the seven formulations, after all the vulcanizates were oxidized by hot air for the same time, the increase in Mooney viscosity gradually decreased. The increase in Mooney viscosity of the vulcanizates of the three new multifunctional antioxidants synthesized in Examples 10, 12 and 13 was smaller than that of the vulcanizates to which antioxidant 4030, light stabilizer 2246, the antioxidant of Comparative Example 1 and no antioxidant was added, indicating that the new multifunctional antioxidant of the present invention has stronger resistance to thermal oxidative aging, among which the new multifunctional antioxidant 1 has the best resistance to thermal oxidative aging.

[0071] 3.2 Flex cracking effect under different formulations The seven samples were subjected to the vulcanized rubber flex cracking resistance test according to GB13934-1992 standard. The test results are shown in Table 2.

[0072] As can be seen from Table 2, in terms of crack test, the three new multifunctional antioxidants of the present invention have better anti-flex cracking effects than antioxidant 4030, light stabilizer light stabilizer 2246, and the antioxidant of comparative example 1. Among them, the new multifunctional antioxidant 1 has the best anti-flex cracking performance.

[0073] 3.3 UV light aging performance test Six natural rubber vulcanizates were placed in a UV light box and aged for 120 hours at 60°C. The changes in tensile strength and elongation at break before and after aging were compared to determine the UV aging resistance of each antioxidant. The test results are shown in Table 3 below.

[0074] From the data in the above table, it can be seen that under the conditions of aging temperature of 60°C and aging time of 120h, the tensile strength and elongation at break of the NR vulcanized rubber with the addition of novel antioxidants 1, 2, and 3 and the NR vulcanized rubber with the addition of light stabilizer 2246 have a slight decrease, while the tensile strength of the NR vulcanized rubber with the addition of antioxidant 4030 has a significant decrease, while the elongation at break has increased, which may be due to the reduction in the crosslinking density of the vulcanized rubber caused by ultraviolet aging. It can be seen that the ultraviolet aging resistance of the novel antioxidant of the present invention is not much different from that of light stabilizer 2246.

[0075] In summary, the 2,2-bis[4-hydroxy-3-(R-yl)aminophenyl]propane synthesized in the present invention has strong resistance to thermal oxidative aging and photooxidative aging, as well as good resistance to flex cracking, and has less pollution than single amine antioxidants. It is a highly efficient, multifunctional, environmentally friendly, and low-pollution antioxidant.

Claims

1. A diphenylpropane derivative, characterized in that: It has the structural formula shown in the following formula (1): In formula (1), R is selected from the group consisting of an alkyl group, a phenyl group, an alkyl-substituted phenyl group, a cyclohexyl group, and an alkyl-substituted cyclohexyl group.

2. The diphenylpropane derivative according to claim 1, characterized in that: In the alkyl group, alkyl-substituted phenyl group and alkyl-substituted cycloalkyl group, the alkyl group has 1-10 carbon atoms.

3. A method for preparing the diphenylpropane derivative according to claim 1, characterized in that The following steps are involved: (1) Bisphenol A is nitrated with nitric acid to obtain 2,2-bis(4-hydroxy-3-nitrophenyl)propane; (2) 2,2-Bis(4-hydroxy-3-nitrophenyl)propane and ketone are subjected to catalytic hydrogenation reaction in the presence of hydrogen, a catalyst and an initiator to obtain a diphenylpropane derivative represented by formula (1).

4. The preparation method according to claim 3, characterized in that: In step (1), at least one of the following conditions is included: Condition 1: The concentration of nitric acid is 20~80wt%; Condition 2: The molar ratio of bisphenol A to nitric acid is 1:2-5; Condition 3: The temperature of the nitration reaction is 20~80℃; Condition 4: The reaction is carried out in a solvent, preferably, the solvent is an alcohol solvent; Condition 5: First, bisphenol A is mixed with a solvent, and then nitric acid is added dropwise at a reaction temperature to react; preferably, the nitric acid is added dropwise for 1 to 2 hours, and the reaction is continued at a temperature of 1 to 5 hours after the addition is complete.

5. The preparation method according to claim 3 or 4, characterized in that: In step (2), at least one of the following conditions is included: Condition 1: The molar ratio of 2,2-bis(4-hydroxy-3-nitrophenyl)propane to ketone is 1:1.2~2; Condition 2: The ketone is an alkyl ketone, a benzophenone, an alkyl-substituted benzophenone, a cyclohexanone, or an alkyl-substituted cyclohexanone; Condition 3: The catalyst is a palladium-carbon catalyst; Condition 4: The initiator is a Lewis acid, preferably, the Lewis acid is aluminum chloride, copper chloride, iron chloride, zinc chloride or trifluoromethanesulfonate; Condition 5: The amount of catalyst used is 2% to 5% of the mass of 2,2-bis(4-hydroxy-3-nitrophenyl)propane; Condition 6: The amount of initiator is 0.5% to 2% of the mass of 2,2-bis(4-hydroxy-3-nitrophenyl)propane; Condition 7: reaction temperature is 60~90℃; Condition 8: Hydrogen pressure is 2~5Mpa; Condition 9: The reaction is carried out in a solvent, and the solvent is preferably an alcohol solvent.

6. Use of the diphenylpropane derivative according to claim 1 as an antioxidant; preferably, as an antioxidant for rubber or rubber products.

7. An antioxidant mixture, characterized in that: Including the diphenylpropane derivatives described in claim 1.

8. A rubber composition, characterized in that: Including the diphenylpropane derivatives described in claim 1.

9. A rubber product, characterized in that: Comprising the rubber composition according to claim 8; preferably, the rubber product is a tire.

10. 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, characterized in that: The diphenylpropane derivative according to claim 1 or the antioxidant mixture according to claim 7 is added to rubber and / or rubber products.

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