Antioxidant for rubber and method for producing same

Abstract

The present invention provides a rubber antioxidant having a structure represented by formula A and a method for producing the same, wherein R, R a and R b is as defined herein. The rubber antioxidant of the present invention can impart excellent resistance to thermal oxidative aging, resistance to ozone aging, and resistance to discoloration and durability to rubber. TIFF2025536060000074.tif34170

Description

[Technical Field]

[0001] The present invention belongs to the field of antioxidants, and more particularly to an antioxidant for rubber and a method for producing the same. [Background technology]

[0002] Currently, p-phenylenediamine compounds are commonly used as antioxidants in rubber products, especially tires. These include dialkyl p-phenylenediamines, alkylaryl p-phenylenediamines, and diaryl p-phenylenediamines. The most widely used is the antioxidant 6PPD (N-(1,3-dimethylbutyl)-N'-phenyl p-phenylenediamine). Others include the antioxidant IPPD (N-isopropyl-N'-phenyl p-phenylenediamine), the antioxidant 77PD (N,N'-bis(1,4-dimethylpentyl) p-phenylenediamine), and the antioxidant DTPD (a mixture of diphenyl p-phenylenediamine, di(tolyl) p-phenylenediamine, and phenyltolyl p-phenylenediamine). Summary of the Invention [Problem to be solved by the invention]

[0003] In recent years, users have become increasingly concerned about the aging resistance and surface discoloration of rubber products and tires. Existing antioxidant products rapidly migrate to the surface of rubber products and tires during use, resulting in contamination, discoloration, and deterioration of the surface of the rubber products and tires. However, the rapid migration also results in rapid consumption of the antioxidant, resulting in poor lasting protection. Non-staining antioxidants such as the antioxidant CMA (N-cyclohexyl-p-methoxyaniline) have excellent resistance to ozone aging and radiation aging, but their low migration resistance means they offer poor lasting protection. [Means for solving the problem]

[0004] To address the above-mentioned problems, the present invention provides a rubber antioxidant with a new structure and a green synthesis process thereof. The rubber antioxidant of the present invention has excellent resistance to thermal oxidative aging, ozone aging, discoloration resistance, and durability, and has little effect on rubber processing / vulcanization and pre-aging physical properties. The present invention also provides an environmentally friendly green method for synthesizing the rubber antioxidant of the present invention.

[0005] More specifically, one aspect of the present invention provides a compound represented by formula A that can be used as an antioxidant for rubber.

[0006] [ka]

[0007] In Formula A, R is selected from a C1 to C20 chain hydrocarbon group, a C3 to C20 alicyclic hydrocarbon group, a C6 to C20 aryl group, and a C1 to C20 alkoxy group; R a is selected from H, a C1-C20 alkyl group, a C3-C20 cycloalkyl group, a phenyl group, a C7-C20 alkylphenyl group, a C1-C20 alkyloxy group, a C3-C20 cycloalkyloxy group, and a C7-C20 alkylphenyloxy group; R b is selected from H, a C1 to C20 alkyl group, a C3 to C20 cycloalkyl group, a phenyl group, and a C7 to C20 alkylphenyl group; The compound represented by formula A is R a is selected from H, a C1-C20 alkyl group, a C3-C20 cycloalkyl group, a phenyl group, and a C7-C20 alkylphenyl group, and R b does not include compounds where is H.

[0008] In one or more embodiments, the compound of formula A of the present invention has the structure shown in formula B:

[0009] [ka]

[0010] In Formula B, R is selected from a C1 to C20 chain hydrocarbon group, a C3 to C20 alicyclic hydrocarbon group, and a C6 to C20 aryl group; R c and R d are each independently selected from a C1 to C10 alkyl group, a C3 to C10 cycloalkyl group, a phenyl group, and a C7 to C10 alkylphenyl group.

[0011] In one or more embodiments, in Formula B, R is selected from a C3-C10 branched chain hydrocarbon group, a C3-C10 cycloalkyl group, and a C6-C10 aryl group; more preferably, R is selected from a C4-C6 branched chain alkyl group and a C4-C6 cycloalkyl group; more preferably, R is 1-methylpropyl, 1,3-dimethylbutyl, or cyclohexyl.

[0012] In one or more embodiments, in Formula B, R c and R d are each independently selected from C1 to C6 alkyl groups and C4 to C6 cycloalkyl groups, and more preferably, R c and R d are each independently a methyl group or an ethyl group.

[0013] In one or more embodiments, the compound of formula A of the present invention has the structure shown in formula I:

[0014] [ka]

[0015] In Formula I, R is selected from a C1 to C20 chain hydrocarbon group, a C3 to C20 alicyclic hydrocarbon group, a C6 to C20 aryl group, and a C1 to C20 alkoxy group; R1 is selected from a C1 to C20 alkyl group, a C3 to C20 cycloalkyl group, and a C7 to C20 alkylphenyl group; R2 is selected from H, a C1 to C20 alkyl group, a C3 to C20 cycloalkyl group, and a C7 to C20 alkylphenyl group.

[0016] In one or more embodiments, in Formula I, R is selected from a C3-C10 branched chain hydrocarbon group, a C3-C10 cycloalkyl group, and a C6-C10 aryl group; more preferably, R is selected from a C4-C6 branched chain alkyl group, a C4-C6 cycloalkyl group, and a phenyl group; more preferably, R is 1-methylpropyl, 1,3-dimethylbutyl, cyclohexyl, or phenyl.

[0017] In one or more embodiments, in Formula I, R1 is selected from a C1-C10 alkyl group, a C3-C10 cycloalkyl group, and a C7-C10 alkylphenyl group, more preferably, R1 is selected from a C1-C6 alkyl group and a C4-C6 cycloalkyl group, and more preferably, is a methyl group or an ethyl group.

[0018] In one or more embodiments, in Formula I, R2 is selected from H, a C1-C10 alkyl group, a C3-C10 cycloalkyl group, and a C7-C10 alkylphenyl group, more preferably R2 is selected from H, a C1-C6 alkyl group, and a C4-C6 cycloalkyl group, more preferably H, a methyl group, or an ethyl group.

[0019] In one or more embodiments, the compounds of formula I of the present invention have the structure shown in formula II or formula III.

[0020] [ka]

[0021] In Formula II and Formula III, R, R1, and R2 are as described in any embodiment herein.

[0022] In one or more embodiments, the compound of formula A of the present invention is

[0023] [ka]

[0024] [ka]

[0025] [ka]

[0026] Selected from.

[0027] Another aspect of the present invention provides a method for preparing a compound of formula A of the present invention, said method comprising the steps of:

[0028] (1) A compound represented by formula C and a compound represented by formula D are subjected to a condensation reaction under the action of a first catalyst to obtain a condensation product containing a compound represented by formula E and / or a compound represented by formula F, and then the condensation product is subjected to a reduction reaction under the action of H2 and a second catalyst to obtain a compound represented by formula X;

[0029] [ka]

[0030] (2) The compound of formula X is subjected to a reductive alkylation reaction with an aldehyde or ketone in the presence of H2 and a third catalyst to obtain the compound of formula A.

[0031] [ka]

[0032] R and R in Formula C, Formula D, Formula E, Formula F, Formula X and Formula A a , R b is as defined in any embodiment herein.

[0033] In one or more embodiments, in step (1), the first catalyst is one or more selected from an alkali metal hydroxide, an alkali metal alkoxide, a quaternary ammonium base, and a combination of an alkali metal hydroxide and a tetraalkylammonium halide.

[0034] In one or more embodiments, in step (1), the molar ratio of the first catalyst to the compound of Formula C is 0.1:1 to 2:1, preferably 0.9:1 to 1.1:1.

[0035] In one or more embodiments, in step (1), the molar ratio of the compound of formula C to the compound of formula D is 2:1 to 15:1, preferably 4:1 to 10:1, and more preferably 5:1 to 8:1.

[0036] In one or more embodiments, in step (1), the temperature of the condensation reaction is 40 to 90°C, preferably 65 to 85°C.

[0037] In one or more embodiments, in step (1), the condensation reaction is carried out under vacuum conditions, with a pressure range of −0.09 to −0.1 MPa.

[0038] In one or more embodiments, in step (1), the second catalyst is a porous metal catalyst or a supported metal catalyst, and the porous metal catalyst is preferably one or more selected from Raney nickel, Raney cobalt, and Raney copper. The metal in the supported metal catalyst is preferably one or more selected from nickel, cobalt, copper, platinum, palladium, ruthenium, and rhodium. The support in the supported metal catalyst is preferably one or more selected from carbon, alumina, silica gel, and molecular sieves.

[0039] In one or more embodiments, in step (1), the mass ratio of the metal in the second catalyst to the condensate is 0.0001:1 to 0.2:1.

[0040] In one or more embodiments, in step (1), the temperature of the reduction reaction is 40 to 120°C, preferably 60 to 90°C, and the hydrogen pressure is 0.5 to 5 MPa, preferably 1 to 2 MPa.

[0041] In one or more embodiments, in step (2), the third catalyst is a supported metal catalyst, the metal in the supported metal catalyst is preferably one or more selected from nickel, cobalt, copper, platinum, palladium, ruthenium, and rhodium, and the support in the supported metal catalyst is preferably one or more selected from carbon, alumina, silica gel, and molecular sieves.

[0042] In one or more embodiments, in step (2), the molar ratio of the aldehyde or ketone to the compound of Formula X is 1:1 to 15:1.

[0043] In one or more embodiments, in step (2), the reduction reaction temperature is 40 to 150° C., and the hydrogen pressure is 0.5 to 5 MPa.

[0044] Another aspect of the present invention provides compounds of formula X which can be used as intermediates in the preparation of compounds of formula A of the present invention.

[0045] [ka]

[0046] In formula X, R a , R b is as defined in any embodiment herein.

[0047] The present invention further provides a method for preparing a compound of formula X of the present invention, the method comprising: condensing a compound of formula C with a compound of formula D under the action of a first catalyst to obtain a condensation product containing a compound of formula E and / or a compound of formula F; and then reducing the condensation product under the action of H and a second catalyst to obtain a compound of formula X.

[0048] [ka]

[0049] R in Formula C, Formula D, Formula E, Formula F and Formula X a , R b is as defined in any embodiment herein.

[0050] In one or more embodiments, the first catalyst is one or more selected from alkali metal hydroxides, alkali metal alkoxides, quaternary ammonium bases, and combinations of alkali metal hydroxides and tetraalkylammonium halides.

[0051] In one or more embodiments, the molar ratio of the first catalyst to the compound of Formula C is from 0.1:1 to 2:1, preferably from 0.1:1 to 1.1:1.

[0052] In one or more embodiments, the molar ratio of the compound of formula C to the compound of formula D is from 2:1 to 15:1, preferably from 4:1 to 10:1, and more preferably from 5:1 to 8:1.

[0053] In one or more embodiments, the temperature of the condensation reaction is 40 to 90°C, preferably 65 to 85°C.

[0054] In one or more embodiments, the condensation reaction is carried out under vacuum conditions, with a pressure range of −0.09 to −0.1 MPa.

[0055] In one or more embodiments, the second catalyst is a porous metal catalyst or a supported metal catalyst, and the porous metal catalyst is preferably one or more selected from Raney nickel, Raney cobalt, and Raney copper. The metal in the supported metal catalyst is preferably one or more selected from nickel, cobalt, copper, platinum, palladium, ruthenium, and rhodium. The support in the supported metal catalyst is preferably one or more selected from carbon, alumina, silica gel, and molecular sieves.

[0056] In one or more embodiments, the mass ratio of the metal in the second catalyst to the condensate is 0.0001:1 to 0.2:1.

[0057] In one or more embodiments, the temperature of the reduction reaction is 40 to 120°C, preferably 60 to 90°C.

[0058] In one or more embodiments, the hydrogen pressure in the reduction reaction is 0.5 to 5 MPa, preferably 1 to 2 MPa.

[0059] Another aspect of the present invention provides a rubber composition comprising a compound of formula A, a compound of formula B, a compound of formula I and / or a compound of formula II of the present invention.

[0060] Another aspect of the present invention provides a rubber product comprising the rubber composition according to any embodiment herein, preferably the rubber product is a tire.

[0061] The present invention further provides a method for improving the thermal oxidative aging resistance, ozone aging resistance and / or discoloration resistance of rubber or a rubber product, which method comprises adding a compound of formula A, a compound of formula B, a compound of formula I and / or a compound of formula II of the present invention to rubber or a rubber product. [Brief explanation of the drawings]

[0062] FIG. 1 shows the simulated colors of each rubber material in the test example after 15 days of weather aging, and from left to right, the simulated colors are Rubber Material 1, Rubber Material 2, Rubber Material 3, Rubber Material 4, Rubber Material 5, Rubber Material 6, and Rubber Material 7. DETAILED DESCRIPTION OF THE INVENTION

[0063] To enable those skilled in the art to understand the features and advantages of the present invention, the following general explanations and definitions are provided for terms referred to in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meanings that are understood by those skilled in the art with respect to the present invention, and in the event of any conflict, the definitions herein shall prevail.

[0064] The theories or mechanisms described and disclosed herein, whether correct or incorrect, are not intended to limit the scope of the present invention in any way; that is, the present invention can be practiced without being limited by any particular theory or mechanism.

[0065] All features defined herein in the form of numerical or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for brevity and convenience only, and the description of a numerical or percentage range should therefore be considered to encompass and specifically disclose all possible subranges and individual numerical values ​​(including integers and fractions) within the range.

[0066] For the sake of brevity, this specification does not describe all possible combinations of various technical features in each embodiment or example. Therefore, unless there is a contradiction in the combination of these technical features, the technical features in each embodiment or example can be arbitrarily combined, and all combinations should be considered to be within the scope of this specification.

[0067] In this specification, a chain hydrocarbon group refers to a linear or branched saturated or unsaturated hydrocarbon group, and typically contains 1 to 20 carbon atoms (a C1 to C20 chain hydrocarbon group), for example, 1 to 10 carbon atoms (a C1 to C10 chain hydrocarbon group). Examples of the chain hydrocarbon group include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, 1-methylpropyl, s-butyl, t-butyl, n-hexyl, isohexyl, 1,3-dimethylbutyl, 1,4-dimethylpentyl, t-octyl, vinyl, propenyl, and ethynyl groups.

[0068] In this specification, the term "alicyclic hydrocarbon group" refers to a group in which carbon atoms are bonded in a ring, and typically contains 3 to 20 carbon atoms (C3 to C20 alicyclic hydrocarbon group), for example, 3 to 10 carbon atoms (C3 to C10 alicyclic hydrocarbon group). Examples of alicyclic hydrocarbon groups include, but are not limited to, an isobornyl group, a cyclohexyl group, a norbornyl group, a norbornenyl group, a dicyclopentadienyl group, an ethynylcyclohexyl group, and an ethynylcyclohexenyl group.

[0069] As used herein, the term "aryl group" refers to a monovalent group formed by removing one hydrogen atom from an aromatic carbon of an aromatic hydrocarbon molecule. The number of ring carbon atoms in an aryl group is typically 6 to 20. Exemplary aryl groups include phenyl and naphthyl groups. The aryl group may be optionally substituted with an alkyl group, a cycloalkyl group, and / or an aryl group. The number of substituents is typically one or two.

[0070] As used herein, an alkyl group refers to a linear or branched monovalent saturated hydrocarbon group, typically containing 1 to 20 carbon atoms (C1-C20 alkyl group), for example, 1 to 10 carbon atoms (C1-C10 alkyl group). Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, 1-methylpropyl, and 1,3-dimethylbutyl groups.

[0071] As used herein, an alkoxy group refers to a bond between an alkyl group and an oxygen atom and may contain 1 to 20 carbon atoms (C1-C20 alkoxy group). Alkoxy groups may be classified as straight-chain, branched-chain, or cyclic. Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, n-propoxy, and isopropoxy.

[0072] As used herein, the term "cycloalkyl group" refers to a monovalent saturated hydrocarbon ring containing 3 to 10 carbon atoms, preferably 3 to 8 carbon atoms. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and adamantyl.

[0073] In this specification, the term "alkylphenyl group" refers to a phenyl group substituted with one or more alkyl groups, and the total number of carbon atoms including the phenyl group is usually 20 or less, preferably 7 to 10 carbon atoms (C7-C10 alkylphenyl group). Examples of alkylphenyl groups include, but are not limited to, tolyl, ethylphenyl, propylphenyl, and butylphenyl groups.

[0074] Compound of Formula A The present inventors have discovered that a compound having a structure represented by formula A (compound of formula A) can be used as an antioxidant for rubber, and has anti-aging properties, discoloration resistance and / or durability equivalent to or greater than those of the antioxidant 6PPD, and has little effect on the processability / vulcanizability of rubber and the physical properties before aging.

[0075] [ka]

[0076] wherein R is selected from a C1 to C20 chain hydrocarbon group, a C3 to C20 alicyclic hydrocarbon group, a C6 to C20 aryl group, and a C1 to C20 alkoxy group; R ais selected from H, a C1-C20 alkyl group, a C3-C20 cycloalkyl group, a phenyl group, a C7-C20 alkylphenyl group, a C1-C20 alkyloxy group, a C3-C20 cycloalkyloxy group, and a C7-C20 alkylphenyloxy group; R b is selected from H, a C1 to C20 alkyl group, a C3 to C20 cycloalkyl group, a phenyl group, and a C7 to C20 alkylphenyl group; The compound of formula A is R a is selected from H, a C1-C20 alkyl group, a C3-C20 cycloalkyl group, a phenyl group, and a C7-C20 alkylphenyl group, and R b does not include compounds where is H.

[0077] In some embodiments, in Formula A, R a is selected from a C1 to C20 alkyl group, a C3 to C20 cycloalkyl group, a phenyl group, a C7 to C20 alkylphenyl group, a C1 to C20 alkyloxy group, a C3 to C20 cycloalkyloxy group, and a C7 to C20 alkylphenyloxy group.

[0078] In some embodiments, in Formula A, R a is selected from a C1 to C10 alkyl group, a C3 to C10 cycloalkyl group, a phenyl group, a C7 to C10 alkylphenyl group, a C3 to C10 branched alkyloxy group, a C3 to C10 cycloalkyloxy group, and a C7 to C10 alkylphenyloxy group.

[0079] In some embodiments, in Formula A, R b is selected from H, a C1 to C10 alkyl group, a C3 to C10 cycloalkyl group, a phenyl group, and a C7 to C10 alkylphenyl group.

[0080] Compound of Formula B In some embodiments, the compound of formula A of the present invention has the structure shown in formula B:

[0081] [ka]

[0082] wherein R is selected from a C1 to C20 chain hydrocarbon group, a C3 to C20 alicyclic hydrocarbon group, and a C6 to C20 aryl group; R c and R d are each independently selected from a C1 to C10 alkyl group, a C3 to C10 cycloalkyl group, a phenyl group, and a C7 to C10 alkylphenyl group.

[0083] In some embodiments, in Formula B, R is selected from a C1 to C18 linear hydrocarbon group, a C3 to C18 alicyclic hydrocarbon group, and a C6 to C18 aryl group.

[0084] In some embodiments, in Formula B, R is selected from a C3-C10 branched hydrocarbon group (e.g., a C3-C10 branched alkyl group), a C3-C10 cycloalkyl group, and a C6-C10 aryl group. Examples of C3-C10 branched alkyl groups include isopropyl, 1-methylpropyl, 1-methylbutyl, 1,2-dimethylpropyl, 1-methylpentyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 1-ethylbutyl, 2-methylpentyl, 1,2-dimethylpentyl, 1,3-dimethylpentyl, 1,4-dimethylpentyl, 3-heptyl, 4-heptyl, 2-octyl, 3-octyl, 4-octyl, 1,2-dimethylhexyl, 1,3-dimethylhexyl, and 1,4-dimethylhexyl. Examples of C3-C10 cycloalkyl groups include a cyclohexyl group. In some preferred embodiments, in Formula B, R is selected from a C4 to C6 branched alkyl group and a C4 to C6 cycloalkyl group, more preferably a 1-methylpropyl group, a 1,3-dimethylbutyl group, or a cyclohexyl group.

[0085] In Equation B, R c and R d may be the same or different. In some embodiments, in Formula B, R c and R dare each independently selected from a C1 to C6 alkyl group and a C4 to C6 cycloalkyl group. In some preferred embodiments, in Formula B, R c and R d are each independently a methyl group or an ethyl group. c is selected from a methyl group and an ethyl group, and R d is a methyl group. In some embodiments, R c and R d are all methyl groups.

[0086] In Equation B, R c and R d There is no particular limitation on the position of on the benzene ring.

[0087] In some embodiments, in Formula B, R c is in the meta position of the -NH- group, and R d is in the meta position of the -NH-R group. In some embodiments, in Formula B, R c is in the ortho position of the -NH- group, and R d is in the ortho position to the -NH-R group. In some embodiments, in Formula B, R c is in the ortho position of the -NH- group, and R d is in the meta position of the -NH-R group. In some embodiments, in Formula B, R c is in the meta position of the -NH- group, and R d is in the ortho position to the -NH-R group.

[0088] In some embodiments, the compound of Formula B is

[0089] [ka]

[0090] Selected from.

[0091] Compound of Formula B' In some embodiments, the compound of formula A of the present invention has the structure shown in formula B'.

[0092] [ka]

[0093] wherein R is selected from a C1 to C20 chain hydrocarbon group, a C3 to C20 alicyclic hydrocarbon group, and a C6 to C20 aryl group; R c is H, R d is selected from a C1 to C10 alkyl group, a C3 to C10 cycloalkyl group, a phenyl group, and a C7 to C10 alkylphenyl group.

[0094] In some embodiments, in Formula B', R is selected from a C1 to C18 linear hydrocarbon group, a C3 to C18 alicyclic hydrocarbon group, and a C6 to C18 aryl group.

[0095] In some embodiments, in Formula B', R is selected from a C3-C10 branched hydrocarbon group (e.g., a C3-C10 branched alkyl group), a C3-C10 cycloalkyl group, and a C6-C10 aryl group. Examples of C3-C10 branched alkyl groups include isopropyl, 1-methylpropyl, 1-methylbutyl, 1,2-dimethylpropyl, 1-methylpentyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 1-ethylbutyl, 2-methylpentyl, 1,2-dimethylpentyl, 1,3-dimethylpentyl, 1,4-dimethylpentyl, 3-heptyl, 4-heptyl, 2-octyl, 3-octyl, 4-octyl, 1,2-dimethylhexyl, 1,3-dimethylhexyl, and 1,4-dimethylhexyl. Examples of C3-C10 cycloalkyl groups include a cyclohexyl group. In some preferred embodiments, in Formula B', R is selected from a C4 to C6 branched alkyl group, a C4 to C6 cycloalkyl group, and a C6 to C10 aryl group, more preferably a 1-methylpropyl group, a 1,3-dimethylbutyl group, a cyclohexyl group, or a phenyl group.

[0096] In formula B', R d There is no particular limitation on the position of on the benzene ring.

[0097] In some embodiments, in Formula B', R d is in the meta position to the -NH-R group. In some embodiments, in Formula B', R d is in the ortho position to the -NH-R group.

[0098] In some embodiments, the compound of formula B' is

[0099] [ka]

[0100] Selected from.

[0101] Compounds of Formula I In some embodiments, the compound of Formula A of the present invention has a structure shown in Formula I. The present inventors have discovered that a compound having a structure shown in Formula I (compound of Formula I) can be used as an antioxidant for rubber, and has ozone aging resistance, thermal oxidative aging resistance, discoloration resistance, and / or durability equivalent to or better than the antioxidant 6PPD, and has little effect on the processability / vulcanizability of the rubber and the physical properties before aging.

[0102] [ka]

[0103] wherein R is selected from a C1 to C20 chain hydrocarbon group, a C3 to C20 alicyclic hydrocarbon group, a C6 to C20 aryl group, and a C1 to C20 alkoxy group; R1 is selected from a C1 to C20 alkyl group, a C3 to C20 cycloalkyl group, and a C7 to C20 alkylphenyl group; R2 is selected from H, a C1 to C20 alkyl group, a C3 to C20 cycloalkyl group, and a C7 to C10 alkylphenyl group.

[0104] In a preferred embodiment, R is selected from a C3-C10 branched-chain hydrocarbon group, a C3-C10 cycloalkyl group, and a C6-C10 aryl group. Examples of C3-C10 branched-chain alkyl groups include isopropyl, 1-methylpropyl, 1-methylbutyl, 1,2-dimethylpropyl, 1-methylpentyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 1-ethylbutyl, 2-methylpentyl, 1,2-dimethylpentyl, 1,3-dimethylpentyl, 1,4-dimethylpentyl, 3-heptyl, 4-heptyl, 2-octyl, 3-octyl, 4-octyl, 1,2-dimethylhexyl, 1,3-dimethylhexyl, and 1,4-dimethylhexyl. Examples of C3-C10 cycloalkyl groups include cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Examples of C6-C10 aryl groups include phenyl, tolyl, ethylphenyl, xylyl, and naphthyl. In some embodiments, R is selected from a C4-C6 branched alkyl group, a C4-C6 cycloalkyl group, and a phenyl group. In some embodiments, R is a 1-methylpropyl group, a 1,3-dimethylbutyl group, a cyclohexyl group, or a phenyl group.

[0105] In preferred embodiments, R1 is selected from a C1-C10 alkyl group, a C3-C10 cycloalkyl group, and a C7-C10 alkylphenyl group. In some embodiments, R1 is selected from a C1-C10 alkyl group and a C3-C10 cycloalkyl group. In some embodiments, R1 is selected from a C1-C6 alkyl group and a C4-C6 cycloalkyl group. In some embodiments, R1 is selected from a C1-C6 alkyl group. In some embodiments, R1 is a methyl group or an ethyl group.

[0106] In some embodiments, in compounds of Formula I, the R1O- group is located ortho or para to the -NH- group of the benzene ring to which it is attached.

[0107] In preferred embodiments, R2 is selected from H, a C1-C10 alkyl group, a C3-C10 cycloalkyl group, and a C7-C10 alkylphenyl group. In some embodiments, R2 is selected from H, a C1-C10 alkyl group, and a C3-C10 cycloalkyl group. In some embodiments, R2 is selected from H, a C1-C6 alkyl group, and a C4-C6 cycloalkyl group. In some embodiments, R2 is selected from H, a C1-C6 alkyl group, and a C4-C6 cycloalkyl group. In some embodiments, R2 is H, a methyl group, or an ethyl group.

[0108] In some embodiments, in compounds of Formula I, the R 1 O— group is located meta to the —NHR group on the benzene ring to which it is attached.

[0109] In some embodiments, R2 is H, R is selected from a C3-C10 branched chain hydrocarbon group and a C3-C10 cycloalkyl group, preferably a C4-C6 branched chain alkyl group and a C4-C6 cycloalkyl group, and R1 is selected from a C1-C10 alkyl group, a C3-C10 cycloalkyl group and a C7-C10 alkylphenyl group, preferably a C1-C10 alkyl group and a C3-C10 cycloalkyl group, more preferably a C1-C6 alkyl group and a C4-C6 cycloalkyl group, for example a C1-C6 alkyl group. In some embodiments, R2 is H, R is 1-methylpropyl, 1,3-dimethylbutyl or cyclohexyl, and R1 is a methyl or ethyl group.

[0110] In some embodiments, R2 is selected from a C1-C10 alkyl group, a C3-C10 cycloalkyl group, and a C7-C10 alkylphenyl group, preferably a C1-C10 alkyl group and a C3-C10 cycloalkyl group, and more preferably a C1-C6 alkyl group and a C4-C6 cycloalkyl group, for example, a C1-C6 alkyl group; R is selected from a C3-C10 branched chain hydrocarbon group, a C3-C10 cycloalkyl group, and a C6-C10 aryl group, preferably a C4-C6 branched chain alkyl group, a C4-C6 cycloalkyl group, and a phenyl group; and R1 is selected from a C1-C10 alkyl group, a C3-C10 cycloalkyl group, and a C7-C10 alkylphenyl group, preferably a C1-C10 alkyl group and a C3-C10 cycloalkyl group, and more preferably a C1-C6 alkyl group and a C4-C6 cycloalkyl group, for example, a C1-C6 alkyl group. In some embodiments, R2 is a methyl or ethyl group, R is a 1-methylpropyl group, a 1,3-dimethylbutyl group, a cyclohexyl group, or a phenyl group, and R1 is a methyl or ethyl group.

[0111] In some embodiments, the compound of Formula I of the present invention has the structure shown in Formula II or Formula III.

[0112] [ka]

[0113] In Formula II and Formula III, R, R1 and R2 are as described in any of the previous embodiments.

[0114] The present inventors have found that, compared to the antioxidant 6PPD, the compound of formula II can impart superior thermal oxidative aging resistance to rubber.

[0115] In some embodiments, the compound of formula I of the present invention is

[0116] [ka]

[0117] [ka]

[0118] Selected from.

[0119] Compound of Formula X The present invention also provides compounds of formula X that can be used as intermediates in the preparation of compounds of formula A, compounds of formula B, compounds of formula B', compounds of formula I, compounds of formula II and compounds of formula III.

[0120] [ka]

[0121] In the formula X, R a and R b is R in any of the embodiments of the compound of formula A above. a and R b or R in any of the examples of compounds of formula B or B' above. c and R d or as defined as -OR1 and R2 in any of the above examples of compounds of formula I, compounds of formula II or compounds of formula III.

[0122] In some embodiments, as intermediates to the compounds of formula II and III, the compounds of formula X of the present invention have the structure shown in formula XI or formula XII.

[0123] [ka]

[0124] In Formula XI and Formula XII, R1 and R2 are as described in any embodiment of the compound of Formula I above.

[0125] In some embodiments, the compound of formula X of the present invention is

[0126] [ka]

[0127] [ka]

[0128] Selected from.

[0129] Methods for preparing compounds of formula A and formula X The present invention provides a method for preparing a compound of formula X and a compound of formula A, comprising the steps of:

[0130] (1) A compound represented by formula C and a compound represented by formula D are subjected to a condensation reaction under the action of a first catalyst to obtain a condensation product containing a compound represented by formula E and / or a compound represented by formula F, and then the condensation product is subjected to a reduction reaction under the action of H2 and a second catalyst to obtain a compound represented by formula X;

[0131] [ka]

[0132] (2) The compound of formula X is subjected to a reductive alkylation reaction with an aldehyde or ketone in the presence of H2 and a third catalyst to obtain the compound of formula A.

[0133] [ka]

[0134] R and R in Formula C, Formula D, Formula E, Formula F, Formula X and Formula A a , R b is as defined in any embodiment herein.

[0135] R contained in the compounds of formula A of the present invention a and R b group, or R contained in the compounds of formula B or B' of the present invention c and R d The -OR1 and R2 groups contained in the compounds of formula I, II or III of the present invention may be used to select the corresponding R a and R b Depending on the R group contained in the compound of formula A, the compound of formula B, the compound of formula B', the compound of formula I, the compound of formula II or the compound of formula III of the present invention, the appropriate aldehyde or ketone in step (2) can be identified and prepared accordingly to obtain the compound of formula A, the compound of formula B, the compound of formula B', the compound of formula I, the compound of formula II or the compound of formula III of the present invention.

[0136] The first catalyst used in step (1) can be one or more selected from alkali metal hydroxides, alkali metal alkoxides, quaternary ammonium bases, and combinations of alkali metal hydroxides and tetraalkylammonium halides. Alkali metal hydroxides applicable to the present invention include sodium hydroxide, potassium hydroxide, lithium hydroxide, etc. Alkali metal alkoxides applicable to the present invention include sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide, sodium tert-butoxide, potassium tert-butoxide, sodium tert-amylate, potassium tert-amylate, etc. Quaternary ammonium bases are compounds with the general formula RNOH, where R represents four identical or different aliphatic or aromatic groups. The R group in the quaternary ammonium base applicable to the present invention can be one or more selected from methyl, ethyl, propyl, D, etc. Examples of quaternary ammonium bases applicable to the present invention include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, etc. The first catalyst can also be a combination of an alkali metal hydroxide and a tetraalkylammonium halide. The general formula of tetraalkylammonium chloride is RNX, where R represents four identical or different aliphatic or aromatic groups, such as methyl, ethyl, propyl, or butyl, and X represents a halogen atom, such as fluorine, chlorine, bromine, or iodine. Examples of combinations of alkali metal hydroxide and a tetraalkylammonium halide include sodium hydroxide and tetrabutylammonium bromide. The molar ratio of the first catalyst to the compound of formula C can be 0.1:1 to 2:1, preferably 0.9:1 to 1.1:1, such as 1.05:1, 1.1:1, or 1.5:1.

[0137] In some embodiments, in step (1), the compound of formula C is first salted with the first catalyst, and then the compound of formula D is added dropwise to carry out the condensation reaction.

[0138] In step (1), the condensation product obtained by condensing the compound of formula C with the compound of formula D in the presence of the first catalyst may be one or both of a nitro compound represented by formula E and a nitroso compound represented by formula F, and may also contain an azobenzene compound. The molar ratio of the compound of formula C to the compound of formula D may be 2:1 to 15:1, preferably 4:1 to 10:1, and more preferably 5:1 to 8.1, for example, 6:1 or 7:1.

[0139] The condensation reaction in step (1) can be carried out at 40 to 90°C, preferably 65 to 85°C, and for example, the reaction temperature may be 60°C, 70°C, 75°C, or 80°C. The condensation reaction is carried out under vacuum conditions, and the pressure range is -0.09 to -0.1 MPa.

[0140] The second catalyst used in step (1) can be a porous metal catalyst or a supported metal catalyst. Porous metal catalysts are also called sponge metal catalysts. Porous metal catalysts applicable to the present invention include Raney nickel (also called skeleton nickel), Raney cobalt, Raney copper, etc. Supported metal catalysts include a metal that serves as the catalytic active center and a support that supports the metal. Metals used in supported metal catalysts applicable to the present invention include nickel, cobalt, copper, platinum, palladium, ruthenium, rhodium, etc. Supports include carbon, alumina, silica gel, molecular sieves, etc., and the carbon used as a support can be activated carbon. The molar ratio of the metal to the condensate in the second catalyst can be 0.0001:1 to 0.2:1.

[0141] In step (1), the condensate produced by the condensation reaction is subjected to a hydrogenation reduction reaction under the action of a second catalyst to produce a compound of formula X. The reduction reaction in step (1) can be carried out at 40 to 120°C, preferably 60 to 90°C, and the reaction temperature can be, for example, 70°C, 75°C, or 80°C. The hydrogen pressure in the reduction reaction can be 0.5 to 5 MPa, for example, 1 MPa, 1.5 MPa, 2 MPa, or 2.5 MPa.

[0142] In step (1), compound C itself can be used as the solvent, or a solvent such as toluene or xylene can be used. After the reaction in step (1) is completed, the reaction mixture is filtered, washed with water, and phase-separated. The organic phase is then distilled under reduced pressure to remove light components, thereby obtaining the compound of formula X.

[0143] The third catalyst used in step (2) can be the supported metal catalyst, such as Pt / C, and the molar ratio of the metal to the compound of formula X in the third catalyst can be 0.0001:1 to 0.2:1.

[0144] In step (2), the compound of formula X is subjected to a hydrogenolytic alkylation reaction with an aldehyde or ketone under the action of a third catalyst to produce a compound of formula A. After the reaction, the carbonyl carbon atom of the aldehyde or ketone is bonded to the amino nitrogen atom in the compound of formula A. Therefore, depending on the R group contained in the compound of formula A to be produced, an appropriate aldehyde or ketone can be selected for the reaction. For example, 4-methyl-2-pentanone can be used to prepare a compound of formula A in which the R group is 1,3-dimethylbutyl, and cyclohexanone can be used to prepare a compound of formula A in which the R group is cyclohexyl. When the R group in the compound of formula A is an aryl group, a ketone as a precursor of the aryl group, a hydrogen acceptor, and a water-transfer agent are added to the reaction system and reacted. For example, a compound of formula A in which the R group is a phenyl group can be prepared using cyclohexanone, a hydrogen acceptor, and a water-transfer agent. The hydrogen acceptor can be nitrobenzene. The water-transfer agent can be toluene. The molar ratio of the aldehyde or ketone to the compound of formula X can be 1:1 to 15:1, for example, 2:1, 3:1, 5:1, 8:1, or 10:1. The reaction temperature in step (2) can be 40 to 150°C, for example, 50°C, 80°C, 100°C, or 120°C. The hydrogen pressure in step (2) can be 0.5 to 5 MPa, for example, 1 MPa, 1.5 MPa, 2 MPa, or 2.5 MPa.

[0145] In step (2), the aldehyde or ketone used as the reaction raw material may be used as a solvent. After the reaction in step (2) is completed, the reaction mixture is filtered and distilled under reduced pressure to remove light components, thereby obtaining the compound of formula A.

[0146] In the present invention, liquid chromatography (LC) or gas chromatography (GC) can be used to determine whether the reaction in each step has reached its end point and to determine an appropriate reaction time.

[0147] The process for preparing the compounds of formula X and formula A of the present invention has the advantages of being environmentally friendly, generating virtually no wastewater, eliminating the need for expensive bromide raw materials, allowing the catalyst to be recycled and reused, reducing solid waste, and using low reaction temperatures.

[0148] Rubber compositions and rubber products The present invention further provides a rubber composition containing the compound of formula A, the compound of formula B, the compound of formula B', the compound of formula (I), the compound of formula II, or the compound of formula III as an antioxidant. Hereinafter, the compound of formula A, the compound of formula B, the compound of formula B', the compound of formula I, the compound of formula II, and the compound of formula III will be referred to as the antioxidant of the present invention.

[0149] The raw materials for rubber compositions generally include diene elastomers, reinforcing fillers, antioxidants, crosslinking agents, etc. In this specification, the rubber composition includes unvulcanized rubber and vulcanized rubber. Unvulcanized rubber can be vulcanized (cured) to produce vulcanized rubber.

[0150] The raw materials for the rubber composition of the present invention contain 30 to 70 parts by weight of a reinforcing filler, 0.1 to 8 parts by weight of an antioxidant, and 0.5 to 3 parts by weight of a crosslinking agent relative to 100 parts by weight of a diene elastomer. Unless otherwise specified, parts by weight in this specification are based on 100 parts by weight of the diene elastomer contained in the raw materials for the rubber composition.

[0151] In this specification, the term "diene elastomer" refers to an elastomer whose monomer contains a diene (e.g., butadiene, isoprene). The diene elastomer applicable to the present invention may be any of various diene elastomers well known in the art, including, but not limited to, one or more selected from natural rubber (NR), butadiene rubber (BR), isoprene rubber, styrene-butadiene rubber (SBR), chloroprene rubber (CR), nitrile rubber (NBR), isoprene / butadiene copolymer, isoprene / styrene copolymer, and isoprene / butadiene / styrene copolymer. In some embodiments, in the raw materials of the rubber composition of the present invention, the diene elastomer comprises or consists of natural rubber and butadiene rubber, and the mass ratio of natural rubber to butadiene rubber may be 1:9 to 9:1, 2:8 to 8:2, 3:7 to 7:3, 4:6 to 6:4, 4.5:5.5 to 5.5:4.5, or 1:1.

[0152] The raw materials for the rubber composition of the present invention typically contain 0.1 to 8 parts by weight, preferably 1 to 5 parts by weight, and more preferably 2±0.5 parts by weight of an antioxidant. The rubber composition of the present invention is characterized by containing the antioxidant of the present invention as an antioxidant. In the present invention, the antioxidant of the present invention may account for 50% or more, 60% or more, more than 80%, 90% or more, or 100% of the total mass of the antioxidants contained in the rubber composition.

[0153] The reinforcing filler used in the present invention may be a reinforcing filler commonly used in rubber compositions, including, but not limited to, one or more selected from carbon black, titanium oxide, magnesium oxide, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, clay, and talc. In some embodiments, the reinforcing filler in the rubber composition of the present invention is carbon black. The raw materials for the rubber composition typically contain 30 to 70 parts by weight, preferably 40 to 60 parts by weight, and more preferably 45 to 55 parts by weight of the reinforcing filler. In some embodiments, the raw materials for the rubber composition of the present invention contain 30 to 70 parts by weight, preferably 40 to 60 parts by weight, and more preferably 45 to 55 parts by weight, of carbon black.

[0154] The crosslinking agent can be sulfur. The raw materials for the rubber composition typically contain 0.5 to 3 parts by weight, preferably 1 to 3 parts by weight, and more preferably 1 to 2 parts by weight of the crosslinking agent. In some embodiments, the raw materials for the rubber composition of the present invention contain 0.5 to 3 parts by weight, preferably 1 to 3 parts by weight, and more preferably 1 to 2 parts by weight, e.g., 1.5 to 0.2 parts by weight, 1.5±0.2 parts by weight, of a crosslinking agent such as sulfur.

[0155] The raw materials for the rubber composition of the present invention may further contain other components commonly used in rubber compositions, including, but not limited to, one or more of auxiliary agents and accelerators, and the amounts of auxiliary agents and accelerators used may be those commonly used in the art.

[0156] The auxiliary agent may include a softener used to improve properties such as processability. The softener may include petroleum-based softeners (operating oils) such as naphthenic oil, aromatic oil, process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, and Vaseline. It may also include fatty oil-based softeners such as stearic acid, castor oil, linseed oil, rapeseed oil, coconut oil, waxes (e.g., beeswax, carnauba wax, and lanolin), tall oil, linoleic acid, palmitic acid, and lauric acid. The auxiliary agent may include an activator such as zinc oxide, which can accelerate the vulcanization rate and improve the thermal conductivity, abrasion resistance, and tear resistance of the rubber. Typically, a total of 2 to 20 parts by weight of auxiliary agents are used per 100 parts by weight of diene elastomer. In some embodiments, the raw materials for the rubber composition of the present invention include an operating oil, such as aromatic oil. The raw materials for the rubber composition of the present invention may contain 0 to 20 parts by weight, preferably 1 to 10 parts by weight, more preferably 2 to 8 parts by weight, for example, 5±2 parts by weight, 5±1 parts by weight, of an operating oil such as aromatic oil. In some embodiments, the raw materials for the rubber composition of the present invention may contain a fatty oil-based softener such as stearic acid. The raw materials for the rubber composition of the present invention may contain 0 to 5 parts by weight, preferably 0.5 to 4 parts by weight, more preferably 1 to 3 parts by weight, for example, 2±0.5 parts by weight, 2±0.2 parts by weight, of a fatty oil-based softener such as stearic acid. In some embodiments, the raw materials for the rubber composition of the present invention may contain an activator such as zinc oxide. The raw materials for the rubber composition of the present invention may contain 0 to 10 parts by weight, preferably 2 to 8 parts by weight, more preferably 3 to 7 parts by weight, for example, 5±1 parts by weight, of an activator such as zinc oxide. In some embodiments, the raw materials for the rubber composition of the present invention include an operating oil, a fatty oil-based softener, and an activator. The amounts of the operating oil, fatty oil-based softener, and activator used are as described above.

[0157] The accelerator is typically a vulcanization accelerator and may be one or more selected from sulfonamide vulcanization accelerators, thiazole vulcanization accelerators, thiuram vulcanization accelerators, thiourea vulcanization accelerators, guanidine vulcanization accelerators, dithiocarbamate vulcanization accelerators, aldehydeamine vulcanization accelerators, imidazoline vulcanization accelerators, and xanthate vulcanization accelerators. For example, the accelerator may be accelerator NS (Nt-butyl-2-benzothiazole sulfenamide). In some embodiments, the raw materials for the rubber composition of the present invention include an accelerator such as accelerator NS. The raw materials for the rubber composition of the present invention may include an accelerator such as accelerator NS in an amount of 0 to 1.5 parts by weight, preferably 0.5 to 1.5 parts by weight, more preferably 0.5 to 1.2 parts by weight, e.g., 0.8±0.2 parts by weight, 0.8±0.1 parts by weight.

[0158] Furthermore, if necessary, the rubber composition may contain plasticizers such as DMP (dimethyl phthalate), DEP (diethyl phthalate), DBP (dibutyl phthalate), DHP (diheptyl phthalate), DOP (dioctyl phthalate), DINP (diisononyl phthalate), DIDP (diisodecyl phthalate), BBP (butyl benzyl phthalate), DWP (dilauryl phthalate), and DCHP (dicyclohexyl phthalate). The amount of plasticizer used may be the amount normally used in the relevant technical field.

[0159] The unvulcanized rubber of the present invention can be produced by a conventional rubber mixing method, for example, a two-stage mixing method. That is, in the first stage, a diene elastomer, a reinforcing filler, an auxiliary agent, and an antioxidant are mixed in an internal mixer to obtain a masterbatch. In the second stage, the masterbatch obtained in the first stage is mixed with a crosslinking agent and a vulcanization accelerator in an open mixer to obtain the unvulcanized rubber.

[0160] The unvulcanized rubber of the present invention can be vulcanized by a conventional vulcanization method to obtain a vulcanized rubber. The vulcanization temperature is usually 130 to 200°C, for example, 140 to 150°C, or 145±2°C. The vulcanization time depends on the vulcanization temperature, vulcanization system, and vulcanization kinetics, and is usually 15 to 60 minutes, for example, 20 to 30 minutes, or 25±2 minutes. Before vulcanization, the unvulcanized rubber obtained by kneading may be press-molded into a sheet using a conventional method.

[0161] The present invention also provides a rubber product comprising the rubber composition according to any one of the embodiments of the present invention. Examples of the rubber product include tires, rubber shoes, seals, soundproof panels, and vibration-damping pads. In some embodiments, the rubber product is a tire, for example, comprising a tire tread, a belt layer, and a sidewall. The tire belt layer may contain, in addition to the rubber composition of the present invention, a reinforcing material commonly used in the art.

[0162] The present invention further provides a use of the compound of formula A, the compound of formula B, the compound of formula B', the compound of formula I, the compound of formula II, or the compound of formula III of the present invention for improving the thermal oxidative aging resistance, ozone aging resistance, and / or discoloration resistance of rubber or a rubber product. Preferably, the rubber product is a tire. The use comprises adding the compound of formula A, the compound of formula B, the compound of formula B', the compound of formula I, the compound of formula II, or the compound of formula III described in any embodiment herein as an antioxidant to the rubber or the rubber product. [Example]

[0163] The present invention will be described below with reference to specific examples. These examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The methods, reagents, and materials used in the examples are well known in the art unless otherwise specified. All raw materials used in the examples can be purchased from commercial sources.

[0164] Example 1 Synthesis of Compound I-1 (N-(4-methoxyphenyl)-N'-1,3-dimethylbutyl-1,4-phenylenediamine)

[0165] (1) Synthesis of Compound X-1 A 500 mL four-neck flask was charged with 200 g (1.62 mol) of p-methoxyaniline, 80 mL of xylene, and 133.3 g (0.37 mol) of 25% aqueous tetramethylammonium hydroxide (TMAOH). The mixture was heated to 40-50 °C with stirring and dehydrated by vacuum distillation. The TMAOH and p-methoxyaniline were salted together, and the color of the reaction mixture gradually changed from yellow to reddish purple. The temperature was gradually raised to 70 °C. When the distillate reached approximately half the amount of the 25% tetramethylammonium hydroxide catalyst, 41 g (0.33 mol) of nitrobenzene was added dropwise over approximately 2 hours at 70 °C under reduced pressure (-0.095 MPa). After completion of the addition, the mixture was kept at 70 °C for 1 hour. The completion of the nitrobenzene reaction was confirmed by LC chromatography, and the resulting condensate was obtained.

[0166] The condensed solution was transferred to a 500 mL stainless steel reactor, and 30 g of deionized water and 45 g of skeleton nickel catalyst were added. After three flushes with hydrogen gas, the reaction was carried out at 68 °C and 2.0 MPa. LC confirmed that the reduction of nitro and nitroso compounds was complete. The reaction solution was filtered, washed with water, and phase-separated to obtain the organic phase. The organic phase was distilled under reduced pressure (-0.1 MPa, 190 °C) to obtain 57 g of intermediate compound X-1 (yield: approximately 80%). GC analysis revealed that the content was >99.4%.

[0167] [ka]

[0168] LC-MS(m / z): 214.22(MH + ).

[0169] (2) Synthesis of Compound I-1 57 g of compound X-1, 150 g (1.50 mol) of 4-methyl-2-pentanone, and 0.6 g of Pt / C were added to a 500 mL high-pressure reactor. After purging with hydrogen gas three times, the reaction was carried out by heating and pressurizing to 75°C and 1.6 MPa, with hydrogen gas being replenished as needed. After GC analysis confirmed that the compound X-1 content was less than 0.1%, the temperature was lowered and the reaction was terminated. The catalyst was removed by filtration, and light components were removed by vacuum distillation at -0.1 MPa and 170°C to obtain 77.7 g of compound I-1 (yield approximately 98%), with a GC analysis showing a content of >98.5%. Appearance: Purple solid.

[0170] [ka]

[0171] LC-MS(m / z):298.40 (MH + ).

[0172] Example 2 Synthesis of Compound I-2 (N-(4-methoxyphenyl)-N'-cyclohexyl-1,4-phenylenediamine) (1) Synthesis of Compound X-1 The synthesis of compound X-1 was the same as in Example 1.

[0173] (2) Synthesis of Compound I-2 40 g (0.18 mol) of compound X-1, 80 g (0.81 mol) of cyclohexanone, and 0.8 g of Pt / C were added to a 500 mL high-pressure reactor. After purging with hydrogen gas three times, the reaction was carried out by heating and pressurizing to 100°C and 1.8 MPa, with hydrogen gas being replenished as needed. After GC analysis confirmed that the B1 content was less than 0.1%, the temperature was lowered and the reaction was terminated. The catalyst was removed by filtration, and light components were removed by vacuum distillation at -0.1 MPa and 200°C to obtain 53.2 g of compound I-2 (yield approximately 96%), with a GC analysis showing a content of >97.8%. Appearance: Purple-brown solid.

[0174] [ka]

[0175] LC-MS(m / z):296.41 (MH + ).

[0176] Example 3 Synthesis of Compound I-3 (N-(2-methoxyphenyl)-N'-1-methylpropyl-1,4-phenylenediamine)

[0177] (1) Synthesis of Compound X-2 A 1000 mL four-neck flask was charged with 400.2 g (3.25 mol) of o-methoxyaniline and 200.2 g (0.55 mol) of 25% aqueous tetramethylammonium hydroxide (TMAOH). The mixture was heated to 40-50°C with stirring and dehydrated by vacuum distillation. The TMAOH and o-methoxyaniline formed a salt. During this process, the color of the reaction mixture gradually changed from yellow to reddish-brown. The temperature was gradually raised to 75°C. When the distillate reached approximately 100 g, 61.55 g (0.50 mol) of nitrobenzene was added dropwise at 75°C under reduced pressure (-0.097 MPa) for approximately 3 hours. After the addition was complete, the mixture was kept at this temperature for 1 hour. The completion of the nitrobenzene reaction was confirmed by LC, and the condensed solution was obtained.

[0178] The condensed solution was transferred to a 1000 mL stainless steel reactor, and 100 g of deionized water and 60 g of skeleton nickel catalyst were added. After three cycles of hydrogen gas replacement, the reaction was carried out at 65 °C and 1.5 MPa under elevated temperature and pressure. LC confirmed that the reduction of nitro and nitroso compounds was complete. The reaction solution was filtered, washed with water, and phase-separated. The aqueous phase was concentrated and reused, and the organic phase was distilled under reduced pressure to obtain 84.6 g of intermediate compound X-2 (approximately 79.5% yield). GC analysis revealed a content of >99.2%.

[0179] [ka]

[0180] LC-MS(m / z): 214.26(MH + ).

[0181] (2) Synthesis of Compound I-3 81.5 g (0.38 mol) of compound X-2, 117 g (1.62 mol) of 2-butanone, and 1.0 g of Pt / C were added to a 500 mL high-pressure reactor. The reaction was heated to 70 °C, purged with hydrogen gas, and then pressurized to 1.2 MPa. GC analysis confirmed that the compound X-2 content was less than 0.1%, after which the temperature was lowered and the reaction was terminated. Filtration and vacuum distillation were performed to remove light components such as water and 2-butanone, yielding 99.5 g of compound I-3 (yield approximately 97%), with a GC analysis showing a content of >97.2%. Appearance: Purple liquid.

[0182] [ka]

[0183] LC-MS(m / z):270.37 (MH + ).

[0184] Example 4 Synthesis of Compound I-4 (N-(2-methoxyphenyl)-N'-1,3-dimethylbutyl-1,4-phenylenediamine)

[0185] (1) Synthesis of Compound X-2 The synthesis method of compound X-2 was the same as in Example 3.

[0186] (2) Synthesis of Compound I-4 50 g (0.23 mol) of compound X-2, 100 g (1.0 mol) of 4-methyl-2-pentanone, and 1.0 g of Pt / C were added to a 500 mL high-pressure reactor. The reaction was heated to 90 °C, purged with hydrogen gas, and then pressurized to 1.2 MPa. GC analysis confirmed that the compound X-2 content was less than 0.1%, after which the temperature was lowered and the reaction was terminated. Filtration and vacuum distillation were performed to remove light components such as water and 4-methyl-2-pentanone, yielding 65.1 g of compound I-4 (yield approximately 95%), with a GC analysis showing a content of >98.2%. Appearance: Purple-brown liquid.

[0187] [ka]

[0188] LC-MS(m / z): 298.42(MH + ).

[0189] Example 5 Synthesis of Compound I-5 (N-(2-ethoxyphenyl)-N'-1-methylpropyl-1,4-phenylenediamine)

[0190] (1) Synthesis of Compound X-3 A 500 mL four-neck flask was charged with 220 g (1.6 mol) of o-ethoxycyaniline and 80 g (0.22 mol) of 25% aqueous tetramethylammonium hydroxide (TMAOH). The mixture was heated to 50 °C with stirring and then dehydrated by vacuum distillation to form a salt between TMAOH and o-ethoxycyaniline. During this process, the color of the reaction mixture gradually changed from yellow to reddish-brown. The temperature was gradually raised to 75 °C, and when the distillate reached approximately 100 g, 24.6 g (0.2 mol) of nitrobenzene was added dropwise over approximately 3 hours while distilling at 78 °C under reduced pressure (-0.097 MPa). After the addition was completed, the mixture was kept at this temperature for 1 hour. The completion of the nitrobenzene reaction was confirmed by LC, and the condensation liquid was obtained.

[0191] The condensation solution was transferred to a 500 mL stainless steel reactor, and 30 g of deionized water and 20 g of skeleton nickel catalyst were added. After three cycles of hydrogen gas replacement, the reaction was carried out at 69 °C and 1.6 MPa under elevated temperature and pressure. LC confirmed that the reduction of nitro and nitroso compounds was complete. The reaction solution was filtered, washed with water, and phase-separated. The aqueous phase was concentrated and reused, and the organic phase was distilled under reduced pressure to obtain 34.1 g of intermediate compound X-3 (approximately 75% yield). GC analysis revealed a content of >98.5%.

[0192] [ka]

[0193] LC-MS(m / z):228.26(MH + ).

[0194] (2) Synthesis of Compound I-5 30 g (0.13 mol) of compound X-3, 43.2 g (0.6 mol) of 2-butanone, and 0.6 g of Pt / C were added to a 500 mL high-pressure reactor. The reaction was heated to 70 °C, purged with hydrogen gas, and then pressurized to 1.2 MPa. GC analysis confirmed that the compound X-3 content was less than 0.1%, after which the temperature was lowered and the reaction was terminated. Filtration and vacuum distillation were performed to remove light components such as water and 2-butanone, yielding 35.4 g of compound I-5 (yield approximately 96%), with a GC analysis showing a content of >97.5%. Appearance: Reddish-brown liquid.

[0195] [ka]

[0196] LC-MS(m / z):284.40 (MH + ).

[0197] Example 6 Synthesis of Compound I-6 (N-(2-ethoxyphenyl)-N'-cyclohexyl-1,4-phenylenediamine)

[0198] (1) Synthesis of Compound X-3 The synthesis method of compound X-3 was the same as in Example 5.

[0199] (2) Synthesis of Compound I-6 30 g (0.13 mol) of compound X-3, 98 g (1.0 mol) of cyclohexanone, and 0.8 g of Pt / C were added to a 500 mL high-pressure reactor. The reaction was heated to 100 °C, purged with hydrogen gas, and then pressurized to 1.9 MPa. GC analysis confirmed that the compound X-3 content was less than 0.1%, after which the temperature was lowered and the reaction was terminated. Filtration and vacuum distillation were performed to remove light components such as water and cyclohexanone, yielding 39.5 g of compound I-6 (yield approximately 98%), with a GC analysis showing a content of >99.1%. Appearance: Dark brown solid.

[0200] [ka]

[0201] LC-MS(m / z): 310.42(MH + ).

[0202] Example 7 Synthesis of Compound I-7 (N-(2-methoxyphenyl)-N'-1-methylpropyl-2-methyl-1,4-phenylenediamine)

[0203] (1) Synthesis of Compound X-4 A 500 mL four-neck flask was charged with 175.1 g (1.42 mol) of o-methoxyaniline and 87.59 g (0.24 mol) of 25% aqueous tetramethylammonium hydroxide (TMAOH). The mixture was heated to 40-50 °C with stirring and dehydrated by distillation under reduced pressure (-0.097 MPa). The TMAOH and o-methoxyaniline were salted together, and the color of the reaction mixture gradually changed from yellow to reddish purple. The temperature was gradually raised to 72 °C. When the distillate reached 50% of the 25% tetramethylammonium hydroxide, 30 g (0.22 mol) of m-nitrotoluene was added dropwise over approximately 3 hours. After completion of the addition, the mixture was incubated for 1 hour. The completion of the m-nitrotoluene reaction was confirmed by LC chromatography, and the condensed solution was obtained.

[0204] The condensed solution was transferred to a 500 mL stainless steel reactor, and 30 g of deionized water and 30 g of skeleton nickel catalyst were added. After three flushes with hydrogen gas, the reaction was carried out under a temperature and pressure of 78 °C and 2.0 MPa. LC confirmed that the reduction of nitro and nitroso compounds was complete. After filtration, water washing, and phase separation, the aqueous phase was concentrated and reused. The organic phase was distilled under reduced pressure (-0.1 MPa, 190 °C) to remove light components, yielding 40 g of intermediate compound X-4 (yield approximately 80%). GC analysis revealed a content of >99.2%.

[0205] [ka]

[0206] LC-MS(m / z): 228.24(MH + ).

[0207] (2) Synthesis of Compound I-7 40 g (0.14 mol) of compound X-4, 100 g (1.38 mol) of 2-butanone, and 0.5 g of Pt / C were placed in a 500 mL reactor. The atmosphere was purged with H2 two or three times, and the reaction was then carried out by heating and pressurizing to 90 °C and 1.2 MPa. GC analysis confirmed that the compound X-4 content was less than 0.1%, after which the temperature was lowered and the reaction was terminated. Filtration and vacuum distillation (-0.1 MPa, 180 °C) were performed to remove the water produced during the reaction and light components such as excess 2-butanone, yielding 77.5 g of compound I-7 (yield approximately 97.8%). GC analysis showed that the content was greater than 95.9%. Appearance: Purple-brown solid.

[0208] [ka]

[0209] LC-MS(m / z):284.17 (MH + ).

[0210] Example 8 Synthesis of Compound I-8 (N-(2-methoxyphenyl)-N'-1,3-dimethylbutyl-2-methyl-1,4-phenylenediamine)

[0211] (1) Synthesis of Compound X-4 The synthesis of compound X-4 was the same as in Example 7.

[0212] (2) Synthesis of Compound I-8 30 g (0.1 mol) of compound X-4, 100 g (1 mol) of 4-methyl-2-pentanone, and 0.6 g of Pt / C were placed in a 500 mL reactor. The atmosphere was purged with H2 two or three times, and the reaction was then carried out by heating and pressurizing to 90 °C and 1.5 MPa. GC analysis confirmed that the compound X-4 content was less than 0.1%, after which the temperature was lowered and the reaction was terminated. Filtration and vacuum distillation (-0.1 MPa, 180 °C) were performed to remove the water produced during the reaction and light components such as 4-methyl-2-pentanone, yielding 30.7 g of compound I-8 (yield approximately 98.5%). GC analysis showed that the content was greater than 98.2%. Appearance: Dark purple solid.

[0213] [ka]

[0214] LC-MS(m / z):312.45 (MH + ).

[0215] Example 9 Synthesis of Compound I-9 (N-(2-methoxyphenyl)-N'-cyclohexyl-2-methyl-1,4-phenylenediamine)

[0216] (1) Synthesis of Compound X-4 The synthesis of compound X-4 was the same as in Example 7.

[0217] (2) Synthesis of Compound I-9 30 g (0.1 mol) of compound X-4, 60 g (0.61 mol) of cyclohexanone, and 1.0 g of Pt / C were placed in a 500 mL reactor. The atmosphere was purged with H2 two or three times, and the reaction was then carried out by heating and pressurizing to 100 °C and 2.0 MPa. GC analysis confirmed that the compound X-4 content was less than 0.1%, after which the temperature was lowered and the reaction was terminated. The water produced in the reaction and light components such as excess cyclohexanone were removed by filtration and vacuum distillation (-0.1 MPa, 200 °C), yielding 30.7 g of compound I-9 (yield approximately 99.1%). GC analysis showed that the content was greater than 97.6%. Appearance: Dark brown solid

[0218] [ka]

[0219] LC-MS(m / z):310.41 (MH + ).

[0220] Example 10 Synthesis of Compound I-10 (N-(4-methoxyphenyl)-N'-cyclohexyl-2-methyl-1,4-phenylenediamine)

[0221] (1) Synthesis of Compound X-5 A 500 mL four-neck flask was charged with 200 g (1.62 mol) of p-methoxyaniline and 100 g (0.27 mol) of 25% aqueous tetramethylammonium hydroxide (TMAOH). The mixture was heated to 40-50°C with stirring and dehydrated by distillation under reduced pressure (-0.095 MPa). The TMAOH and p-methoxyaniline were salted together, and the reaction mixture gradually turned reddish-brown. The temperature was gradually raised to 75°C. When the distillate reached 50% of the 25% tetramethylammonium hydroxide, 34.2 g (0.25 mol) of m-nitrotoluene was added dropwise over approximately 3 hours. After completion of the addition, the mixture was kept at room temperature for 1 hour. The completion of the m-nitrotoluene reaction was confirmed by LC, and the resulting condensate was obtained.

[0222] The condensed solution was transferred to a 500 mL stainless steel reactor, and 20 g of deionized water and 30 g of Raney nickel catalyst were added. After three cycles of hydrogen gas replacement, the reaction was carried out at 70 °C and 2.0 MPa under pressure, with hydrogen continuously replenished. After confirming complete reduction of the nitro and nitroso compounds by LC, the reaction mixture was filtered, washed with water, and phase-separated to obtain the organic phase. The organic phase was then distilled under reduced pressure (-0.1 MPa, 220 °C) to remove light components, yielding 45.3 g of intermediate compound X-5 (approximately 79.5% yield), with a GC content of >99.8%.

[0223] [ka]

[0224] LC-MS(m / z):228.28(MH + ).

[0225] (2) Synthesis of Compound I-10 45.3 g (0.15 mol) of compound X-5, 98.1 g (1.0 mol) of cyclohexanone, and 1.0 g of Pt / C were added to a 500 mL stainless steel reactor, pressurized to 2.0 MPa with H2, and heated to 75 °C. The reaction was terminated after GC analysis confirmed that the compound X-5 content was less than 0.1%. Filtration and vacuum distillation (-0.1 MPa, 200 °C) removed light components, yielding 59.7 g of compound I-10 (approximately 97% yield), with a GC analysis showing a compound I-10 content of >96.8%. Appearance: Reddish-brown solid.

[0226] [ka]

[0227] LC-MS(m / z):310.41 (MH + ).

[0228] Example 11 Synthesis of Compound I-11 (N-(4-methoxyphenyl)-N'-phenyl-2-methyl-1,4-phenylenediamine)

[0229] (1) Synthesis of Compound X-5 The synthesis of compound X-5 is the same as in Example 10.

[0230] (2) Synthesis of Compound I-11 30 g (0.1 mol) of compound 10, 9.8 g (0.1 mol) of cyclohexanone, 12.3 g (0.11 mol) of nitrobenzene, 30 mL of toluene, and 1.0 g of Pt / C were added to a 500 mL four-neck flask equipped with a condenser, water separator, and thermometer, and the temperature was raised to 110 °C. The reaction was continued while dehydration continued. When the amount of water produced reached approximately the theoretical amount, GC analysis confirmed that the compound X-5 content was less than 0.1%. The reaction was then terminated. The reaction solution was filtered and distilled under reduced pressure (-0.1 MPa, 200 °C) to remove light components, yielding 115.5 g of compound I-11 (yield: approximately 95%). Appearance: Brown solid.

[0231] [ka]

[0232] LC-MS(m / z):304.39 (MH + ).

[0233] Example 12 Synthesis of Compound B-1 (N-(3-methylphenyl)-N'-1,3-dimethylbutyl-2-methyl-1,4-phenylenediamine)

[0234] (1) Synthesis of Compound X-6 A 500 mL four-neck flask was charged with 132.4 g (1.23 mol) of m-toluidine and 87.6 g (0.24 mol) of 25% aqueous tetramethylammonium hydroxide (TMAOH). The mixture was heated to 40-50 °C with stirring and dehydrated by vacuum distillation. The TMAOH and m-toluidine salts were formed. During this process, the color of the reaction mixture gradually changed from yellow to deep red. The temperature was gradually raised to 72 °C. When the distillate reached 50% of the 25% tetramethylammonium hydroxide catalyst, 30 g (0.22 mol) of m-nitrotoluene was added dropwise over approximately 3 hours while distilling at 72 °C under reduced pressure (-0.098 MPa). After completion of the dropwise addition, the mixture was kept at this temperature for 1 hour. The completion of the m-nitrotoluene reaction was confirmed by LC, and the condensed solution was obtained.

[0235] The condensation solution was transferred to a 500 mL stainless steel reactor, and 50 g of deionized water and 40 g of skeleton nickel catalyst were added. After three cycles of hydrogen gas replacement, the reaction was heated to 75 °C and pressurized to 1.5 MPa. LC confirmed that the reduction of nitro and nitroso compounds was complete. The reaction solution was filtered, washed with water, and phase-separated. The organic phase was distilled under reduced pressure (-0.1 MPa, 160 °C) to remove light components, yielding 37.1 g of compound X-6 (yield: approximately 80%). GC analysis revealed a content of >99.5%.

[0236] [ka]

[0237] LC-MS(m / z): 212.22(MH + ). 1 H NMR (400 MHz, DMSO-d6) δ 6.95 - 6.88 (m, 2H), 6.79 (d, J = 8.3 Hz, 1H), 6.48 (d, J = 2.6 Hz, 1H), 6.43 - 6.30 (m, 4H), 4.80 (s, 2H), 2.14 (s, 3H), 2.02 (s, 3H).

[0238] (2) Synthesis of Compound B-1 37.1 g of compound X-6, 60 g (0.60 mol) of 4-methyl-2-pentanone, and 0.5 g of Pt / C catalyst were added to a reactor. After purging with hydrogen gas three times, the reaction was carried out by heating and pressurizing to 100°C and 1.5 MPa. GC analysis confirmed that the compound X-6 content was less than 0.1%. The reaction was then terminated after the temperature was lowered, the catalyst was removed by filtration, and the light components were removed by vacuum distillation at -0.1 MPa and 180°C, yielding 49.2 g of compound B-1 (yield approximately 95%), with a GC analysis showing a content of >98.5%. Appearance: Reddish-brown solid.

[0239] [ka]

[0240] LC-MS(m / z):296.44(MH + ).

[0241] Example 13 Synthesis of Compound B-2 (N-(3-methylphenyl)-N'-1-methylpropyl-2-methyl-1,4-phenylenediamine)

[0242] (1) Synthesis of Compound X-6 The synthesis of compound X-6 is the same as in Example 12.

[0243] (2) Synthesis of Compound B-2 30g (0.14mol) of compound X-6, 100g (1.38mol) of 2-butanone, and 0.6g of Pt / C catalyst were added to a reactor. After purging with hydrogen gas three times, the reaction was carried out by heating and pressurizing to 80°C and 1.5MPa. GC analysis confirmed that the compound X-6 content was less than 0.1%. The reaction was then terminated after the temperature was lowered, the catalyst was removed by filtration, and light components were removed by vacuum distillation at -0.1MPa and 150°C, yielding 36.7g of compound B-2 (yield approximately 98%), with a GC analysis showing a content of >98.5%. Appearance: Reddish-brown solid.

[0244] [ka]

[0245] LC-MS(m / z):268.40 (MH + ). 1 H NMR (400 MHz, DMSO-d6) δ 6.96 - 6.87 (m, 2H), 6.83 (d, J = 8.4 Hz, 1H), 6.45 (d, J = 2.6 Hz, 1H), 6.42 - 6.29 (m, 4H), 4.98 (d, J= 8.6 Hz, 1H), 2.14 (s, 3H), 2.04 (s, 3H), 1.81 - 1.66 (m, J= 6.7 Hz, 1H), 1.45 (dt, J = 13.9, 7.1 Hz, 1H), 1.21 (dt, J = 13.5, 6.8 Hz, 1H), 0.89 (dd, J = 16.2, 6.6 Hz, 6H).

[0246] Example 14 Synthesis of Compound B-3 (N-(2-methylphenyl)-N'-1-methylpropyl-3-methyl-1,4-phenylenediamine)

[0247] (1) Synthesis of Compound X-7 A 1000 mL four-neck flask was charged with 347.9 g (3.25 mol) of o-toluidine and 200 g (0.55 mol) of 25% aqueous tetramethylammonium hydroxide (TMAOH). The mixture was heated to 60 °C with stirring and dehydrated by vacuum distillation to form a salt between TMAOH and o-toluidine. During this process, the color of the reaction mixture gradually changed from yellow to reddish-brown. The temperature was gradually raised to 80 °C. When the distillate reached half the amount of the 25% tetramethylammonium hydroxide catalyst, 68.5 g (0.50 mol) of o-nitrotoluene was added dropwise over approximately 3 hours while distilling at 80 °C under reduced pressure (-0.097 MPa). After completion of the dropwise addition, the mixture was kept at room temperature for 1 hour. The completion of the o-nitrotoluene reaction was confirmed by LC, and the condensation solution was obtained.

[0248] The condensed solution was transferred to a 500 mL stainless steel reactor, and 65 g of deionized water and 38 g of skeleton nickel catalyst were added. After three cycles of hydrogen gas replacement, the reaction was heated to 78 °C and pressurized to 2.0 MPa. LC confirmed that the reduction of nitro and nitroso compounds was complete. The reaction solution was filtered, washed with water, and phase-separated. The organic phase was distilled under reduced pressure (-0.1 MPa, 180 °C) to remove light components, yielding 31.8 g of intermediate compound X-7 (approximately 30% yield). GC analysis showed a content of >92.5%.

[0249] [ka]

[0250] LC-MS(m / z): 212.20(MH + ).

[0251] (2) Synthesis of Compound B-3 30g (0.14mol) of compound X-7, 117g (1.62mol) of 2-butanone, and 0.8g of Pt / C catalyst were added to a reactor. The temperature was raised to 80°C, the atmosphere was purged with hydrogen gas, and the pressure was increased to 1.5MPa. The reaction was continued. GC analysis confirmed that the compound X-7 content was less than 0.1%. The temperature was lowered and the reaction was terminated. Filtration and vacuum distillation (-0.1MPa, 160°C) were performed to remove light components, yielding 36.8g of compound B-3 (yield approximately 97%). GC analysis showed a content of >95.5%. Appearance: Black solid.

[0252] [ka]

[0253] LC-MS(m / z):268.38 (MH + ).

[0254] Example 15 Synthesis of Compound B-4 (N-(2-methylphenyl)-N'-cyclohexyl-3-methyl-1,4-phenylenediamine)

[0255] (1) Synthesis of Compound X-7 The synthesis of compound X-7 is the same as in Example 14.

[0256] (2) Synthesis of Compound B-4 30g (0.14mol) of compound X-7, 100g (1.02mol) of cyclohexanone, and 0.9g of Pt / C catalyst were added to a 500mL reactor. The temperature was raised to 70°C, the atmosphere was purged with hydrogen gas, and the pressure was increased to 1.8MPa. GC analysis confirmed that the compound X-7 content was less than 0.1%. The temperature was then lowered and the reaction was terminated. Filtration and vacuum distillation (-0.1MPa, 190°C) were performed to remove light components, yielding 39.0g of compound B-4 (yield approximately 94.8%). GC analysis revealed a content of >93.7%. Appearance: Black solid.

[0257] [ka]

[0258] LC-MS(m / z):294.41 (MH + ).

[0259] Example 16 Synthesis of Compound B-5 (N-(2-methylphenyl)-N'-1-methylpropyl-2-methyl-1,4-phenylenediamine)

[0260] (1) Synthesis of Compound X-8 A 1000 mL four-neck flask was charged with 175 g (1.6 mol) of o-toluidine and 100 g (0.27 mol) of 25% aqueous tetramethylammonium hydroxide (TMAOH). The mixture was heated to 60 °C with stirring and dehydrated by vacuum distillation to form a salt between TMAOH and o-toluidine. During this process, the color of the reaction mixture gradually changed from yellow to reddish-brown. The temperature was gradually raised to 75 °C, and when the distillate reached half the amount of the 25% tetramethylammonium hydroxide catalyst, 34.2 g (0.25 mol) of m-nitrotoluene was added dropwise over approximately 3 hours while distilling at 80 °C under reduced pressure (-0.097 MPa). After completion of the addition, the mixture was kept at room temperature for 1 hour. The completion of the m-nitrotoluene reaction was confirmed by LC chromatography, and the condensation solution was obtained.

[0261] The condensation solution was transferred to a 500 mL stainless steel reactor, and 35 g of deionized water and 30 g of skeleton nickel catalyst were added. After three cycles of hydrogen gas replacement, the reaction was heated to 75 °C and pressurized to 1.5 MPa. LC confirmed complete reduction of the nitro and nitroso compounds. The reaction solution was filtered, washed with water, and phase-separated. The organic phase was distilled under reduced pressure (-0.1 MPa, 170 °C) to remove light components, yielding 42.4 g of intermediate compound X-8 (approximately 80% yield). GC analysis revealed a content of >99.5%.

[0262] [ka]

[0263] LC-MS(m / z): 212.26(MH + ).

[0264] (2) Synthesis of Compound B-5 40g (0.18mol) of compound X-8, 100g (1.39mol) of 2-butanone, and 0.8g of Pt / C catalyst were placed in a 500mL reactor. The temperature was raised to 78°C, the atmosphere was purged with hydrogen gas, and the pressure was increased to 1.8MPa. GC analysis confirmed that the compound X-8 content was less than 0.1%. The temperature was then lowered and the reaction was terminated. Filtration and vacuum distillation (-0.1MPa, 160°C) were performed to remove light components, yielding 47.5g of compound B-5 (approximately 98% yield), with a GC analysis showing a content of >98.5%. Appearance: Brown solid.

[0265] [ka]

[0266] LC-MS(m / z):268.39 (MH + ).

[0267] Example 17 Synthesis of Compound B-6 (N-(2-methylphenyl)-N'-cyclohexyl-2-methyl-1,4-phenylenediamine)

[0268] (1) Synthesis of Compound X-8 The synthesis of compound X-8 is the same as in Example 16.

[0269] (2) Synthesis of Compound B-6 30g (0.14mol) of compound X-8, 100g (1.02mol) of cyclohexanone, and 0.9g of Pt / C catalyst were placed in a 500mL reactor. The temperature was raised to 100°C, the atmosphere was purged with hydrogen gas, and the pressure was raised to 2.0MPa. GC analysis confirmed that the compound X-8 content was less than 0.1%, after which the temperature was lowered and the reaction was terminated. Filtration and vacuum distillation (-0.1MPa, 180°C) removed light components, yielding 41.1g of compound B-6 (yield approximately 98.8%). GC analysis showed a content of >98.7%. Appearance: Dark brown solid.

[0270] [ka]

[0271] LC-MS(m / z):294.43 (MH + ).

[0272] Example 18 2-methyl-N-phenyl-1,4-phenylenediamine antioxidant

[0273] (1) Synthesis of intermediate X-9 A 500 mL four-neck flask was charged with 176.5 g (1.89 mol) of aniline and 116.8 g (0.32 mol) of 25% tetramethylammonium hydroxide (TMAOH). The mixture was heated to 40-50°C with stirring and then dehydrated by vacuum distillation to form a salt between the TMAOH and aniline. During this process, the color of the reaction mixture gradually changed from yellow to deep red. The temperature was gradually raised to 70°C. When the distillate reached 50% of the CAT1 input amount, 40 g (0.29 mol) of m-nitrotoluene was added dropwise over approximately 3 hours while distilling under reduced pressure (-0.095 MPa) at 70°C. After completion of the dropwise addition, the mixture was kept at the same temperature for 1 hour. Completion of the m-nitrotoluene reaction was confirmed by LC.

[0274] The condensate was transferred to a 500 mL stainless steel reactor, and 51 g of deionized water and 30 g of catalyst CAT2 were added. After three cycles of hydrogen gas replacement, the reaction was carried out at 75 °C and 1.5 MPa. LC confirmed that the reduction of nitro and nitroso compounds was complete. The reaction was then filtered, washed with water, and phase-separated. The aqueous phase was concentrated and reused, and the organic phase was distilled under reduced pressure to remove light components. 45.9 g of intermediate X-9, 2-methyl-N-phenyl-1,4-phenylenediamine, was obtained (single-pass yield: approximately 79.4%). It was a pink solid with a GC content of >99.8%.

[0275] [ka]

[0276] LC-MS(m / z): 198.22(MH + ). 1 H NMR (400 MHz, DMSO-d6) δ 7.08 - 6.97 (m, 3H), 6.80 (d, J = 8.3 Hz, 1H), 6.57 - 6.46 (m, 4H), 6.40 (dd, J= 8.3, 2.7 Hz, 1H), 4.81 (s, 2H), 2.02 (s, 3H).

[0277] (2) Synthesis of Compound B'-1 46 g (0.23 mol) of intermediate X-9, 70 g (0.70 mol) of 4-methyl-2-pentanone, and 0.8 g of Pt / C were added to a 500 ml reactor. After purging with hydrogen gas three times, the mixture was reacted at 80°C and 1.8 MPa. GC analysis confirmed that the X-9 content was less than 0.1%, and the temperature was lowered to terminate the reaction. Light components were removed by filtration and vacuum distillation (-0.1 MPa, 180°C), yielding 64.0 g of compound B'-1 (yield approximately 98%), with a GC analysis showing a content of >95.8%.

[0278] [ka]

[0279] Appearance: Deep red liquid LC-MS(m / z):282.40 (MH + ). 1 H NMR (400 MHz, DMSO-d6) δ 6.83 (t, J = 7.8 Hz, 1H), 6.80 - 6.74 (m, 2H), 6.68 - 6.61 (m, 1H), 6.60 - 6.54 (m, 2H), 6.53 - 6.47 (m, 2H), 4.87 (s, 1H), 3.39 (t, J = 6.7 Hz, 2H), 2.55 (s, 1H), 2.21 (s, 3H), 2.07 (s, 3H), 1.80 - 1.58 (m, J = 6.8 Hz, 1H), 1.44 (d, J = 13.9 Hz, 1H), 1.31 - 1.09 (m, 1H), 1.06 (d, J = 6.1 Hz, 3H), 0.89 (dd, J = 14.8, 6.6 Hz, 6H).

[0280] (3) Synthesis of Compound B'-2 40 g (0.2 mol) of intermediate X-9, 100 g (1.39 mol) of 2-butanone, and 0.5 g of Pt / C were added to a 500 ml reactor. After purging with hydrogen gas three times, the mixture was reacted at 80°C and 1.2 MPa. GC analysis confirmed that the X-9 content was less than 0.1%, and the temperature was lowered to terminate the reaction. Light components were removed by filtration and vacuum distillation (-0.1 MPa, 190°C), yielding 49.4 g of compound B'-2 (yield approximately 98%), with a GC analysis showing a content of >97.6%.

[0281] [ka]

[0282] Appearance: Reddish-brown liquid LC-MS(m / z):254.35 (MH + ).

[0283] (4) Synthesis of Compound B'-3 40 g (0.2 mol) of intermediate X-9, 100 g (1.02 mol) of cyclohexanone, and 0.8 g of Pt / C were added to a 500 ml reactor. After purging with hydrogen gas three times, the mixture was reacted at 100°C and 2.0 MPa. GC analysis confirmed that the X-9 content was less than 0.1%, and the temperature was lowered to terminate the reaction. Light components were removed by filtration and vacuum distillation (-0.1 MPa, 190°C), yielding 54.4 g of compound B'-3 (yield approximately 97%), with a GC content of >97.8%.

[0284] [ka]

[0285] Appearance: Reddish-brown solid LC-MS(m / z):280.41 (MH + ). 1 H NMR (400 MHz, DMSO-d6) δ 7.08 - 6.99 (m, 3H), 6.83 (d, J = 8.4 Hz, 1H), 6.56 - 6.48 (m, 3H), 6.46 (d, J= 2.6 Hz, 1H), 6.39 (dd, J = 8.4, 2.7 Hz, 1H), 5.12 (d, J = 8.1 Hz, 1H), 3.14 d, J= 10.2, 4.5 Hz, 1H), 2.03 (s, 3H), 1.92 (d, J = 12.1 Hz, 2H), 1.71 (d, J = 11.7 Hz, 3H), 1.64 - 1.50 (m, 1H), 1.40 - 1.01 (m, 6H).

[0286] (3) Synthesis of Compound B'-4 19.8 g (0.1 mol) of intermediate X-9, 9.8 g (0.1 mol) of cyclohexanone, 12.3 g (0.11 mol) of nitrobenzene, 30 mL of toluene, and 1.0 g of Pd / C were added to a 500 mL four-neck flask equipped with a condenser and a water separator, and the temperature was raised to 110 °C. The reaction was continued, and when the amount of water produced reached near the theoretical amount, GC analysis confirmed that the X-9 content was less than 0.1%, and the reaction was then terminated. The reaction solution was filtered and distilled under reduced pressure (-0.1 MPa, 180 °C) to remove light components, yielding 18.2 g of compound B'-4 (yield: approximately 92%).

[0287] [ka]

[0288] Appearance: Brown solid LC-MS(m / z):274.34 (MH + ). 1 H NMR (400 MHz, DMSO-d6) δ 7.96 (s, 1H), 7.26 - 7.11 (m, 4H), 7.11 - 7.05 (m, 2H), 7.05 - 6.98 (m, 3H), 6.97 (d, J = 2.6 Hz, 1H), 6.90 (dd, J = 8.5, 2.7 Hz, 1H), 6.78 - 6.72 (m, 1H), 6.71 - 6.66 (m, 2H), 6.63 (td, J = 7.2, 1.2 Hz, 1H), 2.13 (s, 3H).

[0289] Application Examples Rubber materials were prepared using antioxidant 6PPD and Compounds B-1, B-2, I-3, I-4, I-7, and I-8 in the above examples, and the rubber materials were then subjected to property tests.

[0290] 1. Raw materials Natural rubber (SCR5): Xishuangbanna Sinochemical Rubber Co., Ltd. Butadiene rubber (BR): Shandong Yuhuang Chemical Co., Ltd. Anti-aging agent 6PPD: Seio Chemical Technology Co., Ltd. Carbon black N550, aromatic oil, ZnO, stearic acid, sublimated sulfur (S) and accelerator NS are all raw materials commonly used in the rubber industry.

[0291] 2. Equipment and Instruments FARREL BR1600 Internal Mixer: Farrell, USA X(S)K-160 Open Mixer: Shanghai Shuangyi Rubber and Plastics Machinery Equipment Co., Ltd. 63TDF-DSM type vulcanizer: Huzhou Hongqiao Rubber Machinery Co., Ltd. UR2010SD Vulcanization Tester and UM2050 Mooney Viscometer: U-Know Technology Co., Ltd. Instron 3360 Tensile Tester: Instron Corporation, USA CLM-QLH-150 hot air aging tester:Wuxi Kelai Environmental Technology Co., Ltd. GT-7011-D Flexural Fatigue Tester and OZ-0200AC Ozone Aging Tester: Gaotie Inspection Instrument Co., Ltd. CS-200 type color difference meter: Hangzhou Caifu Technology Co., Ltd. 3. Rubber material compounding formula

[0292] [Table 1]

[0293] 4. Preparation of Rubber Materials According to the formulation shown in Table 1, SCR5 and BR were first plasticized and thoroughly mixed in an internal mixer. After that, ZnO, stearic acid, antioxidants (compound B-1, compound B-2, antioxidant 6PPD, compound I-3, compound I-4, compound I-7, or compound I-8), N550, and aromatic oil were added in sequence and mixed uniformly to obtain a masterbatch. Next, the masterbatch, S, and NS were added to an open mixer and mixed until the rubber material was uniform. The mixture was then sheeted five times, with the roll gap adjusted to an appropriate range to form a sheet, yielding an unvulcanized rubber material.

[0294] After standing for about 15 hours, the vulcanization characteristics, Mooney viscosity and scorch characteristics of the unvulcanized rubber material were measured.

[0295] The unvulcanized rubber material was vulcanized in a vulcanization press (145°C, vulcanization time set in the range of 15 to 30 minutes based on the vulcanization curve of each antioxidant) to obtain a vulcanized rubber material.

[0296] 5.Characteristics test Materials inspection and rubber material property testing were carried out according to the following standards: The Mooney viscosity of the unvulcanized rubber material was measured according to GB / T 1232.1-2016, and the results are shown in Table 2.

[0297] Based on GB / T 1233-2008 Measurement of early vulcanization properties of unvulcanized rubber, the scorch time of the unvulcanized rubber material was measured using a Mooney viscometer (120°C), and the results are shown in Table 2.

[0298] Based on GB / T 9869-2014 Rotorless Vulcanizer for Measuring the Vulcanization Properties of Rubber, the vulcanization rate and degree of vulcanization of the rubber material were measured using a vulcanizer (145°C), and the results are shown in Table 2.

[0299] Based on GB / T 528-2009 Measurement of tensile stress-strain properties of vulcanized or thermoplastic rubber, the initial physical properties (tensile strength and elongation at break) of the vulcanized rubber material were measured, and the results are shown in Table 3.

[0300] According to GB / T 13939-2014 Vulcanized or thermoplastic rubber - Hot air accelerated aging and heat resistance test, the thermal oxidation aging resistance of vulcanized rubber materials was measured, and the results are shown in Table 3.

[0301] Based on GB / T 11206-2019, the test method for surface cracking of vulcanized rubber over time, static ozone aging resistance tests were conducted on vulcanized rubber materials using an ozone aging tester. The test conditions were a static ozone concentration of 50 pphm, a temperature of 40°C, and an elongation rate of 20%. Two sets of tests were conducted for each rubber material, and the results are shown in Table 4. The meanings of 1c, 2c, 3c, and 4c in Table 4 comply with the GB / T 11206-2019 standard.

[0302] Based on GB / T 13642-2015 Dynamic Tensile Test for Ozone Cracking Resistance of Vulcanized or Thermoplastic Rubber, dynamic ozone resistance tests were conducted on vulcanized rubber materials using an ozone aging tester. The test conditions were a dynamic ozone concentration of 50 pphm, a temperature of 40°C, a dynamic elongation of 20%, and a frequency of 0.5 Hz. Two sets of tests were conducted for each rubber material, and the results are shown in Table 5. The designations 1c, 2c, 3c, and 4c in Table 5 comply with standard GB / T 11206-2019.

[0303] The vulcanized rubber material was placed in close contact with an A4 sheet of paper, sealed in a transparent airtight bag, and left outside for 15 days.The color of the surface of the A4 sheet was then measured using a colorimeter, and the results are shown in Table 6 and Figure 1.

[0304] 6. Test Results (1) Processing / Vulcanizability

[0305] [Table 2]

[0306] (2) Properties before and after thermal oxidation aging

[0307] [Table 3]

[0308] (3) Ozone aging resistance

[0309] [Table 4]

[0310] [Table 5]

[0311] (4) Discoloration after 15 days of weathering

[0312] [Table 6]

[0313] As is clear from Table 2, the Mooney viscosity, scorch properties and vulcanization properties of rubber materials 2 to 7 containing the compound of formula A of the present invention are not significantly different from those of rubber material 1 containing 6PPD, indicating that the compound of formula A of the present invention has little effect on the processing properties and vulcanization properties of the rubber material.

[0314] Table 3 shows that the pre-aging physical properties of rubber materials 2 to 7 containing the compound of formula A of the present invention are similar to those of rubber material 1 containing 6PPD. After 48 hours of thermal oxidative aging at 100°C, rubber material 4 containing compound I-3 and rubber material 5 containing compound I-4 showed significantly lower rates of decrease in tensile strength and elongation at break than rubber material 1 containing 6PPD, indicating that the compounds of formula II of the present invention, represented by compounds I-3 and I-4, can impart better thermal oxidative aging resistance to rubber than 6PPD. After 48 hours of thermal oxidative aging at 100°C, rubber material 2 containing compound B-1 showed significantly lower rates of decrease in elongation at break than rubber material 1 containing 6PPD, indicating that compound B-1 can impart good thermal oxidative aging resistance to rubber. After 48 hours of thermal oxidative aging at 100°C, the reduction rates of tensile strength and elongation at break of rubber material 3 containing compound B-2, rubber material 6 containing compound I-7, and rubber material 7 containing compound I-8 were shown to be close to those of rubber material 1.

[0315] The static and dynamic ozone aging results in Tables 4 and 5 show that the ozone aging resistance of rubber materials 2 to 7 containing the compound of formula A of the present invention is equivalent to that of rubber material 1 containing 6PPD.

[0316] The results of discoloration due to weathering and aging in Table 6 show that the discoloration resistance of rubber materials 4 and 7 was equivalent to that of rubber material 1, while rubber materials 2, 3, and 6 showed significantly improved discoloration resistance compared to rubber material 1. That is, the discoloration resistance of compounds I-3 and I-5 was close to that of 6PPD, while B-1, B-2, and I-7 showed better discoloration resistance than 6PPD.

Claims

1. A compound of formula A, 【Chemistry 1】 In Formula A, R is selected from a C1 to C20 linear hydrocarbon group, a C3 to C20 alicyclic hydrocarbon group, a C6 to C20 aryl group, and a C1 to C20 alkoxy group; R a is selected from H, a C1 to C20 alkyl group, a C3 to C20 cycloalkyl group, a phenyl group, a C7 to C20 alkylphenyl group, a C1 to C20 alkyloxy group, a C3 to C20 cycloalkyloxy group, and a C7 to C20 alkylphenyloxy group; R b is selected from H, a C1 to C20 alkyl group, a C3 to C20 cycloalkyl group, a phenyl group, and a C7 to C20 alkylphenyl group; The compound represented by formula A is R a is selected from H, a C1-C20 alkyl group, a C3-C20 cycloalkyl group, a phenyl group, and a C7-C20 alkylphenyl group, and R b Compounds not including compounds where is H.

2. The compound has the structure shown in Formula B: 【Chemistry 2】 In Formula B, R is selected from a C1 to C20 linear hydrocarbon group, a C3 to C20 alicyclic hydrocarbon group, and a C6 to C20 aryl group; R c and R d are each independently selected from a C1 to C10 alkyl group, a C3 to C10 cycloalkyl group, a phenyl group, and a C7 to C10 alkylphenyl group; Preferably, R is selected from a C3-C10 branched chain hydrocarbon group, a C3-C10 cycloalkyl group, and a C6-C10 aryl group, more preferably, R is selected from a C4-C6 branched chain alkyl group and a C4-C6 cycloalkyl group, more preferably, 1-methylpropyl group, 1,3-dimethylbutyl group, or cyclohexyl group; Preferably, R c and R d are each independently selected from C1 to C6 alkyl groups and C4 to C6 cycloalkyl groups, and more preferably, R c and R d and each independently represent a methyl group or an ethyl group.

3. The compound has the structure shown in Formula I: 【Transformation 3】 In Formula I, R is selected from a C1 to C20 linear hydrocarbon group, a C3 to C20 alicyclic hydrocarbon group, a C6 to C20 aryl group, and a C1 to C20 alkoxy group; R 1 is selected from a C1 to C20 alkyl group, a C3 to C20 cycloalkyl group, and a C7 to C20 alkylphenyl group; R 2 is selected from H, a C1-C20 alkyl group, a C3-C20 cycloalkyl group, and a C7-C20 alkylphenyl group; Preferably, R is selected from a C3-C10 branched chain hydrocarbon group, a C3-C10 cycloalkyl group, and a C6-C10 aryl group, more preferably, R is selected from a C4-C6 branched chain alkyl group, a C4-C6 cycloalkyl group, and a phenyl group, more preferably, 1-methylpropyl group, 1,3-dimethylbutyl group, cyclohexyl group, or phenyl group; Preferably, R 1 is selected from C1 to C10 alkyl groups, C3 to C10 cycloalkyl groups, and C7 to C10 alkylphenyl groups, and more preferably, R 1 is selected from C1 to C6 alkyl groups and C4 to C6 cycloalkyl groups, more preferably a methyl group or an ethyl group; Preferably, R 2 is selected from H, a C1-C10 alkyl group, a C3-C10 cycloalkyl group, and a C7-C10 alkylphenyl group, and more preferably, R 2 is selected from H, a C1-C6 alkyl group and a C4-C6 cycloalkyl group, more preferably H, a methyl group or an ethyl group.

4. The compound of claim 3, wherein the compound has the structure shown in Formula II or Formula III. 【Chemistry 4】 (In Formula II and Formula III, R, R 1 and R 2 is as defined in claim 3)

5. The compound is 【Transformation 5】 【Transformation 6】 【Transformation 7】 The compound according to claim 1, characterized in that it is selected from:

6. It includes the following steps: (1) A compound represented by formula C and a compound represented by formula D are subjected to a condensation reaction under the action of a first catalyst to obtain a condensation product containing a compound represented by formula E and / or a compound represented by formula F, and then the condensation product is subjected to H 2 and reducing the compound represented by formula X under the action of a second catalyst, 【Transformation 8】 (2) The compound represented by formula X is reacted with an aldehyde or ketone and H 2 and subjecting the resulting compound to a reductive alkylation reaction under the action of a third catalyst to obtain a compound represented by formula A. 【Chemistry 9】 (However, R and R in Formula C, Formula D, Formula E, Formula F, Formula X and Formula A a , R b is as defined in any one of claims 1 to 5)

7. 7. The method according to claim 6, characterized in that the method has one or more of the following characteristics (a): In step (1), the first catalyst is one or more selected from the group consisting of alkali metal hydroxides, alkali metal alkoxides, quaternary ammonium bases, and combinations of alkali metal hydroxides and tetraalkylammonium halides; in step (1), the molar ratio of said first catalyst to the compound of formula C is between 0.1:1 and 2:1, preferably between 0.9:1 and 1.1:1; in step (1), the molar ratio of the compound of formula C to the compound of formula D is from 2:1 to 15:1, preferably from 4:1 to 10:1, more preferably from 5:1 to 8:1; In step (1), the temperature of the condensation reaction is 40 to 90°C, preferably 65 to 85°C; In step (1), the condensation reaction is carried out under vacuum conditions, with a pressure range of -0.09 to -0.1 MPa; In step (1), the second catalyst is a porous metal catalyst or a supported metal catalyst, the porous metal catalyst is preferably one or more selected from Raney nickel, Raney cobalt, and Raney copper, the metal in the supported metal catalyst is preferably one or more selected from nickel, cobalt, copper, platinum, palladium, ruthenium, and rhodium, and the support in the supported metal catalyst is preferably one or more selected from carbon, alumina, silica gel, and molecular sieves; In step (1), the temperature of the reduction reaction is 40 to 120°C, preferably 60 to 90°C, and the hydrogen pressure is 0.5 to 5 MPa, preferably 1 to 2 MPa; In step (2), the third catalyst is a supported metal catalyst, the metal in the supported metal catalyst is preferably one or more selected from nickel, cobalt, copper, platinum, palladium, ruthenium, and rhodium, and the support in the supported metal catalyst is preferably one or more selected from carbon, alumina, silica gel, and molecular sieves; In step (2), the molar ratio of the aldehyde or ketone to the compound of formula X is 1:1 to 15:1; In step (2), the temperature of the reduction reaction is 40-150°C, and the hydrogen pressure is 0.5-5 MPa.

8. The compound of any one of claims 1 to 5, which is a compound represented by formula X. 【Chemistry 10】 (In formula X, R a , R b is the same as claims 1 to 5.)

9. 9. A method for producing the compound of claim 8, comprising:

8. A method comprising step (1) of the method according to claim 6 or 7.

10. A rubber composition comprising the compound according to any one of claims 1 to 5.

11. A rubber product comprising the rubber composition according to claim 10, preferably a tire.

12. 1. A method for improving the thermal oxidative aging resistance, ozone aging resistance and / or discoloration resistance of rubber or a rubber product, comprising:

6. A process comprising adding to rubber or rubber products a compound according to any one of claims 1 to 5.

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