Polyalkyl p-phenylenediamine antioxidants, their intermediates and manufacturing methods

Abstract

The present invention provides a polyalkyl p-phenylenediamine antioxidant having the structure shown in Formula 1, its intermediate, and a method for preparing the same, wherein each group is as defined herein. The polyalkyl p-phenylenediamine antioxidant of the present invention has excellent resistance to thermal oxidative aging and ultraviolet aging. TIFF2025536062000038.tif30170

Description

[Technical Field]

[0001] The present invention belongs to the field of p-phenylenediamine antioxidants, and more particularly to polyalkyl p-phenylenediamine antioxidants, their intermediates and preparation methods. [Background technology]

[0002] Currently, p-phenylenediamine antioxidants are widely used in rubber products such as rubber tires. They offer highly effective ozone protection, as well as excellent general anti-aging effects against flex aging, oxygen, and heat, and also provide excellent protection against harmful metals such as copper and manganese. For example, the antioxidant 6PPD, whose chemical name is N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, is a highly effective rubber antioxidant.

[0003] Chinese Patent Application Publication No. 113072741A discloses an environmentally friendly p-phenylenediamine antioxidant and its preparation method. The structure of the environmentally friendly p-phenylenediamine antioxidant disclosed in this application is as follows:

[0004] [ka]

[0005] Among these, the antioxidant will not convert to a quinone compound after aging of the rubber material if the following specific conditions are met: at least one of x and w is 1, at least one of y and z is 1, and when x and z are both 1, y and w are not both 0. The manufacturing process provided in this application involves first subjecting aniline to a C—N coupling reaction with p-bromonitrobenzene having a corresponding substituent, and then reducing the resulting coupling product under catalytic conditions in a hydrogen atmosphere to obtain a reaction intermediate. The reaction intermediate is then subjected to a reductive amination reaction with an aldehyde or ketone under catalytic conditions to obtain the p-phenylenediamine antioxidant. This method requires the use of expensive bromides and noble metal organophosphorus complex catalysts, resulting in low conversion rates and yields, relatively complex separation and purification procedures, and the generation of wastewater containing metal bromide salts, making it unsuitable for industrial production.

[0006] 4-Aminodiphenylamine is an important intermediate for p-phenylenediamine antioxidants. It can be obtained by the condensation and reduction of aniline or its derivatives with nitrobenzene under basic conditions. It can also be produced by hydrogenation of anilinonitrobenzene, which is obtained by the C-N coupling reaction of aniline with p-halonitrobenzene in the presence of a triphenylphosphine-coordinated palladium catalyst.

[0007] Therefore, there is a need in the art for p-phenylenediamine antioxidants with novel structures and environmentally friendly and eco-friendly production methods. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Chinese Patent Application Publication No. 113072741A Summary of the Invention [Problem to be solved by the invention]

[0009] To address the problems of the prior art, the present invention provides a p-phenylenediamine-based antioxidant with a novel structure and excellent resistance to thermal oxidative aging and UV aging. The present invention also provides a method for producing the p-phenylenediamine-based antioxidant, which has the advantage of being environmentally friendly and not producing the so-called "three wastes." Furthermore, the present invention also provides intermediates used in the production of the p-phenylenediamine-based antioxidant. [Means for solving the problem]

[0010] Specifically, in one aspect, the present invention provides compounds according to Formula I:

[0011] [ka]

[0012] In Formula I, each R1 is independently selected from H, a C1-C18 linear hydrocarbon group, and a C3-C18 alicyclic hydrocarbon group; and a is an integer from 1 to 5; R2, R3, R4, and R5 are each independently selected from H, a C1-C18 chain hydrocarbon group, and a C3-C18 alicyclic hydrocarbon group, and at least one group among R2, R3, R4, and R5 is not H; R6 and R7 are each independently selected from a C1 to C18 chain hydrocarbon group and a C3 to C18 alicyclic hydrocarbon group, or R6 and R7 together form a C3 to C18 aliphatic ring.

[0013] In one or more embodiments, in Formula I, each R1 is independently selected from H and a C1-C8 alkyl group.

[0014] In one or more embodiments, in Formula I, a is an integer from 1 to 2.

[0015] In one or more embodiments, in Formula I, R2, R3, R4, and R5 are each independently selected from H and a C1-C8 alkyl group.

[0016] In one or more embodiments, in Formula I, 2 to 3 of R2, R3, R4, and R5 are H.

[0017] In one or more embodiments, in Formula I, R6 and R7 are each independently selected from a C1 to C8 alkyl group and a C3 to C8 cycloalkyl group, or R6 and R7 form a C3 to C8 aliphatic ring.

[0018] Another aspect of the present invention provides a method for preparing a compound of formula I, comprising the steps of: (1) A compound represented by formula A and a compound represented by formula B are subjected to a condensation reaction under the action of a first catalyst to obtain a condensation product containing a compound represented by formula C and / or a compound represented by formula C', 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 II;

[0019] [ka]

[0020] (2) The compound of formula II is subjected to a reductive alkylation reaction with the compound of formula D in the presence of H2 and a third catalyst to obtain the compound of formula I.

[0021] [ka]

[0022] R1, R2, R3, R4, R5, R6, and R7 in Formula A, Formula B, Formula C, Formula C', Formula D, Formula II, and Formula I are as defined in any embodiment herein.

[0023] 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.

[0024] 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.

[0025] In one or more embodiments, 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.

[0026] In one or more embodiments, in step (1), the molar ratio of the compound represented by formula A to the compound represented by formula B is 2:1 to 15:1, preferably 4:1 to 10:1.

[0027] In one or more embodiments, in step (1), the temperature of the condensation reaction is 40 to 90°C, preferably 65 to 85°C, and the degree of vacuum is -0.09 to -0.99 MPa.

[0028] In one or more embodiments, in step (1), the reaction temperature of the condensate and H2 is 40 to 120°C, preferably 60 to 90°C, and the hydrogen pressure is 0.5 to 5 MPa, preferably 0.5 to 2.5 MPa.

[0029] In one or more embodiments, in step (2), the molar ratio of the compound represented by formula D to the compound represented by formula II is 1:1 to 15:1.

[0030] In one or more embodiments, in step (2), the reaction temperature is 40 to 150° C., and the reaction pressure is 0.5 to 5 MPa.

[0031] Another aspect of the present invention provides compounds according to formula II:

[0032] [ka]

[0033] In Formula II, each R1 is independently selected from H, a C1-C18 linear hydrocarbon group, and a C3-C18 alicyclic hydrocarbon group; and a is an integer from 1 to 5; R2, R3, R4, and R5 are each independently selected from H, a C1 to C18 chain hydrocarbon group, and a C3 to C18 alicyclic hydrocarbon group, and at least one of R2, R3, R4, and R5 is not H.

[0034] In one or more embodiments, in Formula II, each R1 is independently selected from H and a C1-C8 alkyl group.

[0035] In one or more embodiments, in Formula II, a is an integer from 1 to 2.

[0036] In one or more embodiments, in Formula II, R2, R3, R4, and R5 are each independently selected from H and a C1-C8 alkyl group.

[0037] In one or more embodiments, in Formula II, 2 to 3 of R2, R3, R4, and R5 are H.

[0038] Another aspect of the present invention provides a method for preparing a compound of the structure shown in formula II: The method includes condensing a compound represented by formula A and a compound represented by formula B under the action of a first catalyst to obtain a condensation product containing a compound represented by formula C and / or a compound represented by formula C', and then reducing the condensation product under the action of H2 and a second catalyst to obtain a compound represented by formula II.

[0039] [ka]

[0040] R1, R2, R3, R4, and R5 in Formula A, Formula B, Formula C, Formula C', and Formula II are as defined in any embodiment herein.

[0041] 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.

[0042] 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.

[0043] In one or more embodiments, in step (1), the molar ratio of the compound represented by formula A to the compound represented by formula B is 2:1 to 15:1, preferably 4:1 to 10:1.

[0044] In one or more embodiments, in step (1), the temperature of the condensation reaction is 40 to 90°C, preferably 65 to 85°C, and the degree of vacuum is -0.09 to -0.99 MPa.

[0045] In one or more embodiments, in step (1), the reaction temperature of the condensate and H2 is 40 to 120°C, preferably 60 to 90°C, and the hydrogen pressure is 0.5 to 5 MPa, preferably 0.5 to 2.5 MPa.

[0046] Another aspect of the present invention provides a rubber composition comprising a compound of Formula I as described in any embodiment herein.

[0047] 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.

[0048] Another aspect of the present invention provides a method for improving the thermal oxidative aging and / or ultraviolet aging resistance of rubber or a rubber article, comprising adding to the rubber or rubber article a compound of Formula I as described in any embodiment herein. DETAILED DESCRIPTION OF THE INVENTION

[0049] 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.

[0050] 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.

[0051] As used herein, the terms "comprise," "include," "contain," and similar terms encompass the meanings of "consist essentially of" and "consist of," for example, if "A comprises B and C," then "A consists essentially of B and C" and "A consists of B and C" should also be considered to be disclosed herein.

[0052] 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.

[0053] In this specification, unless otherwise specified, percent means percent by mass and ratio means mass ratio.

[0054] It is to be understood that the embodiments or examples described herein are not intended to limit the invention, but rather all alternatives, modifications, and equivalents of the methods and materials described herein are included within the scope defined by the claims.

[0055] 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.

[0056] In this specification, the term "chain hydrocarbon group" refers to a linear or branched saturated or unsaturated hydrocarbon group, typically containing 1 to 18 carbon atoms (C1 to C18 chain hydrocarbon group). Examples of chain hydrocarbon groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-hexyl, isohexyl, 1,3-dimethylbutyl, 1,4-dimethylpentyl, t-octyl, vinyl, propenyl, and ethynyl groups.

[0057] 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 18 carbon atoms (C3 to C18 alicyclic hydrocarbon group). Examples of alicyclic hydrocarbon groups include, but are not limited to, isobornyl, cyclohexyl, norbornyl, norbornenyl, dicyclopentadienyl, ethynylcyclohexyl, and ethynylcyclohexenyl groups.

[0058] As used herein, alkyl refers to a linear or branched monovalent saturated hydrocarbon group, typically containing 1 to 18 carbon atoms (C1-C18 alkyl), such as 1 to 8 carbon atoms (C1-C8 alkyl). Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, 1-methylpropyl, isobutyl, and 1,3-dimethylbutyl.

[0059] As used herein, a cycloalkyl group refers to a monovalent saturated hydrocarbon ring containing 3 to 18 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 groups.

[0060] Compounds of Formula I The present invention has discovered that a polyalkyl p-phenylenediamine compound having the structure shown in Formula II (abbreviated as the compound of Formula I) can be used as a rubber antioxidant, and can impart better thermal oxidative aging resistance and UV aging resistance to rubber than the antioxidant 6PPD.

[0061] [ka]

[0062] In Formula I, each R1 is independently selected from H, a C1-C18 linear hydrocarbon group, and a C3-C18 alicyclic hydrocarbon group; and a is an integer from 1 to 5; R2, R3, R4, and R5 are each independently selected from H, a C1-C18 chain hydrocarbon group, and a C3-C18 alicyclic hydrocarbon group, and at least one group among R2, R3, R4, and R5 is not H; R6 and R7 are each independently selected from a C1 to C18 chain hydrocarbon group and a C3 to C18 alicyclic hydrocarbon group, or R6 and R7 together form a C3 to C18 aliphatic ring.

[0063] In some preferred embodiments, each R1 is independently selected from H and a C1-C8 alkyl group. In some embodiments, each R1 is independently selected from H, a methyl group, and an ethyl group. In some embodiments, each R1 is independently selected from H and a methyl group. In some embodiments, a is 1 or 2. When a is 1, R1 is preferably located at the ortho or para position of the -NH- group. When a is 2, it is preferred that two R1s are located at the ortho or meta position of -NH-, and that the two R1s are adjacent to each other.

[0064] In some preferred embodiments, each R1 is independently selected from a C1 to C8 alkyl group. In some embodiments, each R1 is independently selected from a C1 to C4 alkyl group. In some embodiments, each R1 is a methyl group. In some embodiments, a is 1 or 2. When a is 1, R1 is preferably located at the ortho or para position of the -NH- group. When a is 2, it is preferred that two R1s are located at the ortho or meta position of -NH-, and that the two R1s are adjacent to each other.

[0065] In some preferred embodiments, R2, R3, R4, and R5 are each independently selected from H and a C1-C8 alkyl group, and preferably, two or three of R2, R3, R4, and R5 are H. In some embodiments, R2, R3, R4, and R5 are each independently selected from H and a C1-C4 alkyl group. In some embodiments, R2, R3, R4, and R5 are each independently selected from H and a methyl group. When three of R2, R3, R4, and R5 are H, preferably, R2 is not H. When two of R2, R3, R4, and R5 are H, preferably, R2 and R4 are not H, or R2 and R3 are not H.

[0066] In some preferred embodiments, R6 and R7 are each independently selected from a C1-C8 alkyl group and a C3-C8 cycloalkyl group, or R6 and R7 form a C3-C8 aliphatic ring. In some embodiments, R6 and R7 are each independently selected from a C1-C6 alkyl group, e.g., a C1-C4 alkyl group, or R6 and R7 form a C5-C7 aliphatic ring, e.g., a C6 aliphatic ring. In some embodiments, R6 is selected from a C1-C2 alkyl group, e.g., a methyl group, and R7 is selected from a C1-C6 alkyl group, e.g., a C1-C4 alkyl group, or R6 and R7 form a C5-C7 aliphatic ring, e.g., a C6 aliphatic ring. Preferably, the aliphatic ring formed by R6 and R7 is a saturated aliphatic ring.

[0067] In some embodiments, each R1 is independently selected from H and a C1-C4 alkyl group, or each R1 is independently selected from a C1-C4 alkyl group, a is 1 or 2, R2, R3, R4, and R5 are independently selected from H and a C1-C4 alkyl group, and preferably, 2 to 3 groups among R2, R3, R4, and R5 are H, and R6 and R7 are independently selected from a C1-C6 alkyl group, for example, a C1-C4 alkyl group, or R6 and R7 form a C5-C7 aliphatic ring, for example, a C6 aliphatic ring.

[0068] In some embodiments, each R1 is independently selected from H and a C1-C4 alkyl group, preferably H and a methyl group, or each R1 is independently selected from a C1-C4 alkyl group, for example a methyl group, a is 1, and R1 is preferably located at the ortho position of the -NH- group; R2, R3, R4, and R5 are independently selected from H and a C1-C4 alkyl group, preferably H and a methyl group, and preferably, two or three groups among R2, R3, R4, and R5 are H, wherein, preferably, R2 is not H, or R2 and R3 are not H, and R6 and R7 are independently selected from a C1-C6 alkyl group, for example a C1-C4 alkyl group, or R6 and R7 form a C5-C7 aliphatic ring, for example a C6 aliphatic ring.

[0069] In some embodiments, the compound of Formula I is

[0070] [ka]

[0071] Selected from.

[0072] Compound of Formula II The present invention further provides compounds of formula II that can be used as intermediates in the preparation of compounds of formula I.

[0073] [ka]

[0074] In Formula II, R1, a, R2, R3, R4, and R5 are as defined above for R1, a, R2, R3, R4, and R5 in any embodiment of the compound of Formula I.

[0075] In some embodiments, the compound of Formula II is

[0076] [ka]

[0077] Selected from.

[0078] Methods for preparing compounds of formula I and formula II The present invention provides a method for preparing a compound of formula I and a compound of formula II, comprising the steps of: (1) A compound represented by formula A and a compound represented by formula B are subjected to a condensation reaction under the action of a first catalyst to obtain a condensation product containing a compound represented by formula C and / or a compound represented by formula C', 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 II;

[0079] [ka]

[0080] (2) The compound of formula II is subjected to a reductive alkylation reaction with the compound of formula D in the presence of H2 and a third catalyst to obtain the compound of formula I.

[0081] [ka]

[0082] R1, R2, R3, R4, R5, R6, and R7 in Formula A, Formula B, Formula C, Formula C', Formula D, Formula II, and Formula I are as defined in any embodiment herein.

[0083] 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.

[0084] A quaternary ammonium base is a compound having the general formula RNOH, where R is four identical or different aliphatic groups (e.g., alkyl groups) or aromatic groups. In some embodiments, each R group in the quaternary ammonium base is an alkyl group, e.g., each R group is independently selected from methyl, ethyl, propyl, and butyl. Examples of quaternary ammonium bases applicable to the present invention include tetraalkylammonium hydroxides, such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide. The first catalyst can also be a combination of an alkali metal hydroxide and a tetraalkylammonium halide.

[0085] The general formula of tetraalkylammonium halides is RNX, where R is four identical or different aliphatic or aromatic groups, such as methyl, ethyl, propyl, or butyl, and X is a halogen atom, such as fluorine, chlorine, bromine, or iodine. Examples of combinations of alkali metal hydroxides and tetraalkylammonium halides include sodium hydroxide and tetrabutylammonium bromide. In some embodiments, the first catalyst is a quaternary ammonium base, such as a tetraalkylammonium hydroxide.

[0086] The molar ratio of the first catalyst to the compound of formula A may be 0.1:1 to 2:1, preferably 0.1:1 to 0.5:1, such as 0.2:1, 0.3:1, 0.4:1.

[0087] In some embodiments, in step (1), the compound of formula A is first salted with the first catalyst, and then the compound of formula B is added dropwise to carry out the condensation reaction.

[0088] In step (1), the condensation product obtained by condensing the compound of formula A with the compound of formula B in the presence of the first catalyst may be one or both of a nitro compound represented by formula C and a nitroso compound represented by formula C', and may also contain an azobenzene compound. The molar ratio of the compound of formula A to the compound of formula B may be 2:1 to 15:1, preferably 4:1 to 10:1, more preferably 5:1 to 8:1, for example, 6:1 or 7:1.

[0089] The condensation reaction in step (1) can be carried out at 40 to 90°C, preferably 65 to 85°C, and the reaction temperature may be, for example, 60°C, 70°C, 75°C, or 80°C. The condensation reaction is carried out under vacuum conditions, and the vacuum range is -0.09 to -0.99 MPa.

[0090] 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. In some embodiments, the second catalyst is a porous metal catalyst, such as Raney nickel. The molar ratio of the metal to the condensate in the second catalyst can be 0.0001:1 to 0.2:1.

[0091] In step (1), the condensate produced in the condensation reaction is subjected to a hydrogenation reduction reaction under the action of a second catalyst to produce a compound of formula II. 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, preferably 0.5 to 2.5 MPa, for example, 1 MPa, 1.5 MPa, 2 MPa, or 2.5 MPa.

[0092] 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 to recover the second catalyst, the oil-water phase is separated to recover the first catalyst, and the organic phase is distilled to remove light components, thereby obtaining the compound of formula II.

[0093] 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 II in the third catalyst can be 0.0001:1 to 0.2:1.

[0094] In step (2), a compound of formula II is subjected to a hydrogenolytic alkylation reaction with a compound of formula D in the presence of a third catalyst to produce a compound of formula I. After the reaction, the carbonyl carbon atom of formula D is bonded to the amino nitrogen atom of the compound of formula II. Therefore, a compound of formula D appropriate for the R6 and R7 groups contained in the compound of formula I to be produced may be selected for the reaction. The molar ratio of the compound of formula D to the compound of formula II may be 1:1 to 15:1, for example, 2:1, 3:1, 5:1, 8:1, 10:1, or 14:1. The reaction temperature in step (2) may be 40 to 150°C, preferably 50 to 120°C, for example, 50°C, 70°C, 80°C, 100°C, or 120°C. The hydrogen pressure in step (2) may be 0.5 to 5 MPa, preferably 0.5 to 2.5 MPa, for example, 1 MPa, 1.5 MPa, 2 MPa, or 2.5 MPa.

[0095] In step (2), the compound of formula D used as the reaction raw material may be used as a solvent. After the reaction in step (2) is completed, the reaction solution is filtered to recover the third catalyst, and then distilled under reduced pressure to remove light components, thereby obtaining the compound of formula I.

[0096] 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.

[0097] The process for preparing the compounds of Formula I and Formula II of the present invention is environmentally friendly, does not generate wastewater during the preparation of the intermediate II compound, does not require the use of expensive bromides, and allows the catalyst to be recycled and reused.

[0098] Rubber compositions and rubber products The present invention further provides a rubber composition containing the compound of formula I of the present invention as an antioxidant, hereinafter referred to as the antioxidant of the present invention.

[0099] 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.

[0100] 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.

[0101] 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, the diene elastomer in the raw materials of the rubber composition of the present invention includes 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. In some embodiments, the diene elastomer is natural rubber.

[0102] 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.

[0103] 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.

[0104] The crosslinking agent can be sulfur. The raw materials for the rubber composition typically include 0.5 to 3 parts by weight, preferably 1 to 3 parts by weight, of the crosslinking agent. In some embodiments, the raw materials for the rubber composition of the present invention include 0.5 to 3 parts by weight, preferably 1 to 3 parts by weight, e.g., 2.5±0.5 parts by weight, 2.5±0.2 parts by weight, of a crosslinking agent such as sulfur.

[0105] 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.

[0106] 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 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 a fatty oil-based softener and an activator, and the amounts of the petroleum-based softener and the activator used may be as described above.

[0107] The accelerator is typically a vulcanization accelerator and may be one or more selected from sulfonamide-based vulcanization accelerators, thiazole-based vulcanization accelerators, thiuram-based vulcanization accelerators, thiourea-based vulcanization accelerators, guanidine-based vulcanization accelerators, dithiocarbamate-based vulcanization accelerators, aldehydeamine-based vulcanization accelerators, imidazoline-based vulcanization accelerators, and xanthate-based vulcanization accelerators. For example, the accelerator may be N-cyclohexyl-2-benzothiazole sulfenamide (CBS). In some embodiments, the raw materials for the rubber composition of the present invention include an accelerator such as CBS. The raw materials for the rubber composition of the present invention may include 0 to 1.5 parts by weight, preferably 0.2 to 1 part by weight, for example, 0.6±0.2 parts by weight, 0.6±0.1 parts by weight, of an accelerator such as CBS.

[0108] 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.

[0109] 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.

[0110] The unvulcanized rubber of the present invention can be vulcanized using conventional vulcanization methods to obtain a vulcanized rubber. The vulcanization temperature is usually 130°C to 200°C, e.g., 140°C to 160°C, or 150±5°C. The vulcanization time depends on the vulcanization temperature, vulcanization system, and vulcanization kinetics, and is usually 10 to 60 minutes, e.g., 15±5 minutes, or 15±2 minutes. Before vulcanization, the unvulcanized rubber obtained by kneading may be press-molded into a sheet using a conventional method.

[0111] 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.

[0112] The present invention further provides a use of the compound of formula I of the present invention for improving the thermal oxidative aging resistance and / or ultraviolet aging resistance of rubber or a rubber product. Preferably, the rubber product is a tire. The use comprises adding the compound of formula I of the present invention as an antioxidant to the rubber or the rubber product. [Example]

[0113] 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 material compounds used in the examples can be purchased from commercial sources.

[0114] [Example 1]: Synthesis of Compound I-1 (N-Isopropyl-N'-phenyl-2-methyl-1,4-phenylenediamine) (i) Synthesis of Compound II-1 A 500 mL four-neck flask was charged with 139.7 g (1.5 mol) of aniline and 91 g (0.25 mol) of 25% aqueous tetramethylammonium hydroxide (TMAOH). The mixture was heated to 40-55°C with stirring and then dehydrated by vacuum distillation to form a salt between 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 72°C. When the distillate reached approximately 46 mL, 34.3 g (0.25 mol) of 3-nitrotoluene was added dropwise at 72°C under reduced pressure (-0.098 MPa) for approximately 3 hours. After completion of the addition, the mixture was kept at this temperature for 1 hour. The completion of the 3-nitrotoluene reaction was confirmed by LC, and the condensed solution was obtained.

[0115] The condensed 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 mixture was heated to 75 °C and hydrogen gas was passed through at 1.5 MPa to carry out the hydrogenation reduction reaction. LC confirmed that the reduction of nitro and nitroso compounds was complete. The organic phase was then filtered and phase-separated. The organic phase was washed with water and distilled under reduced pressure (-0.1 MPa, 160 °C) to remove aniline and light by-products. The final reduction product (compound II-1) (42.6 g) was obtained by rectification. The product solidified into a yellow solid upon cooling. The yield was approximately 86%, and the content was >99% by GC analysis.

[0116] [ka]

[0117] 1 H NMR (400 MHz, CDCl3) δ 7.22 - 7.15 (m, 2H), 7.03 (d, J = 8.3 Hz, 1H), 6.79 - 6.74 (m, 1H), 6.68 (dt, J= 8.8, 1.7 Hz, 2H), 6.61 (d, J = 2.6 Hz, 1H), 6.54 (dd, J = 8.3, 2.7 Hz, 1H), 5.15 (s, 1H), 3.56 (s, 2H), 2.17 (s, 3H).

[0118] (ii) Synthesis of Compound I-1 40g (0.2mol) of compound II-1, 162.4g (2.8mol) of acetone, and 0.5g of Pt / C catalyst were added to a reactor. After purging with hydrogen gas three times, the reaction was heated to 70°C and hydrogen gas was passed through at 1.5MPa. GC analysis confirmed that the compound II-1 content was less than 0.1%. The reaction was then terminated. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by vacuum distillation at -0.1MPa and 180°C. 48.3g of compound I-1 (yield approximately 99.4%) was obtained, with a content of >98% by GC analysis. After cooling, the mixture solidified to give a pale pink solid.

[0119] [ka]

[0120] 1 H NMR (400 MHz, CDCl3) δ 7.20 - 7.11 (m, 2H), 7.03 (d, J = 8.4 Hz, 1H), 6.77 - 6.70 (m, 1H), 6.65 (dt, J= 8.8, 1.7 Hz, 2H), 6.50 (d, J = 2.7 Hz, 1H), 6.44 (dd, J = 8.4, 2.7 Hz, 1H), 5.13 (s, 1H), 3.71 - 3.43 (m, 1H), 3.34 (brr s, 1H), 2.17 (s, 3H), 1.23 (d, J = 6.3 Hz, 6H).

[0121] [Example 2] Synthesis of Compound I-2 (N-1,3-dimethylbutyl-N'-phenyl-2,6-dimethyl-1,4-phenylenediamine) (i) Synthesis of Compound II-2 A 500 mL four-neck flask was charged with 186.2 g (2 mol) of aniline and 91 g (0.25 mol) of 25% aqueous tetramethylammonium hydroxide (TMAOH). The mixture was heated to 40-55°C with stirring and then dehydrated by vacuum distillation to form a salt between 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 72°C. When the distillate reached approximately 46 mL, 37.8 g (0.25 mol) of 3,5-dimethylnitrobenzene was added dropwise at 72°C under reduced pressure (-0.098 MPa) for approximately 3 hours. After completion of the addition, the mixture was kept at this temperature for 1 hour. The completion of the reaction of 3,5-dimethylnitrobenzene was confirmed by LC, and the condensate was obtained.

[0122] The condensed solution was transferred to a 500 mL stainless steel reactor, and 50 g of deionized water and 50 g of skeleton nickel catalyst were added. After three cycles of hydrogen gas replacement, the mixture was heated to 75 °C and hydrogen gas was passed through at 1.5 MPa to carry out the hydrogenation reduction reaction. LC confirmed that the reduction of nitro and nitroso compounds was complete. The organic phase was then filtered and phase-separated. The organic phase was washed with water and distilled under reduced pressure (-0.1 MPa, 160 °C) to remove aniline and light by-products. The final reduction product (compound II-2) was obtained by rectification (44.3 g). The product solidified into a pale green solid upon cooling. The yield was approximately 82%, and the content was >98% by GC analysis.

[0123] [ka]

[0124] H NMR (400 MHz, CDCl3) δ 7.15 (dd, J = 17.7, 10.1 Hz, 2H), 6.70 (t, J = 7.3 Hz, 1H), 6.49 (s, 2H), 6.47 (d, J= 5.7 Hz, 2H), 4.98 (s, 1H), 3.55 (s, 2H), 2.14 (s, 6H). 13C NMR (101 MHz, CDCl3) δ 147.62, 144.52, 138.11, 129.47, 129.33, 117.47, 115.09, 112.85, 18.44.

[0125] (ii) Synthesis of Compound I-2 43.2g (0.2mol) of compound II-2, 160.3g (1.6mol) of 4-methyl-2-pentanone, and 0.5g of Pt / C catalyst were added to a reactor. After purging with hydrogen gas three times, the reactor was heated to 90°C and hydrogen gas was passed through at 1.5MPa. The reaction was terminated after GC analysis confirmed that the compound II-2 content was <0.1%. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by vacuum distillation at -0.1MPa and 180°C to obtain 59.5g of compound I-2 (yield approximately 99.5%), which had a GC content of >98.2%. The product was a deep red liquid at room temperature.

[0126] [ka]

[0127] 1 H NMR (400 MHz, CDCl3) δ 7.13 (dd, J = 8.4, 7.4 Hz, 2H), 6.68 (t, J = 7.3 Hz, 1H), 6.48 (d, J = 7.6 Hz, 2H), 6.36 (s, 2H), 4.97 (s, 1H), 3.62 - 3.39 (m, 1H), 3.28 (s, 1H), 2.14 (s, 6H), 1.87 - 1.71 (m, 1H), 1.45-1.52 (m, 1H), 1.35 - 1.23 (m, 1H), 1.18 (d, J = 6.2 Hz, 3H), 0.97 (d, J = 6.6 Hz, 3H), 0.95 (d, J = 6.6 Hz, 3H). 13C NMR (101 MHz, CDCl3) δ 147.86, 145.96, 138.07, 129.25, 127.83, 117.21, 112.81, 112.73, 47.15, 46.71, 25.21, 23.07, 22.71, 21.28, 18.61.

[0128] [Example 3] Synthesis of Compound I-3 (N-Cyclohexyl-N'-phenyl-2,6-dimethyl-1,4-phenylenediamine) (i) Synthesis of Compound II-2 The synthesis of compound II-2 is the same as in Example 2.

[0129] (ii) Synthesis of Compound I-3 43.2g (0.2mol) of compound II-2, 156.8g (1.6mol) of cyclohexanone, and 0.5g of Pt / C catalyst were added to a reactor and purged with hydrogen gas three times. The reaction was then heated to 100°C and hydrogen gas was passed through at 1.5MPa. GC analysis confirmed that the compound II-2 content was <0.1%. The reaction was then terminated. The temperature was lowered, the catalyst was removed by filtration, and the mixture was distilled under reduced pressure at -0.1MPa and 180°C to remove light components, yielding 59.6g of compound I-3 (yield approximately 99.5%). GC analysis showed a content of >98.2%. The product was a deep red liquid at room temperature.

[0130] [ka]

[0131] 1H NMR (400 MHz, CDCl3) δ 7.16 (dd, J = 8.4, 7.4 Hz, 2H), 6.71 (t, J = 7.3 Hz, 1H), 6.50 (d, J = 7.6 Hz, 2H), 6.41 (s, 2H), 4.99 (s, 1H), 3.50 (s, 1H), 3.38 - 3.18 (m, 1H), 2.17 (s, 6H), 2.16 - 2.06 (m, 2H), 1.89 - 1.76 (m, 2H), 1.76 - 1.64 (m, 1H), 1.51 - 1.36 (m, 2H), 1.35 - 1.09 (m, 3H). 13 C NMR (101 MHz, CDCl3) δ 147.83, 145.62, 138.02, 129.21, 127.87, 117.18, 112.87 , 112.69, 51.86, 33.69, 26.01, 25.11, 18.56.

[0132] [Example 4] Synthesis of Compound I-4 (N-Cyclohexyl-N'-2-methylphenyl-2-methyl-1,4-phenylenediamine) (i) Synthesis of Compound II-4 A 500 mL four-neck flask was charged with 160.5 g (1.5 mol) of 2-methylaniline and 91 g (0.25 mol) of 25% aqueous tetramethylammonium hydroxide (TMAOH). The mixture was heated to 40-50 °C with stirring and dehydrated by vacuum distillation to form a salt between TMAOH and 2-methylaniline. 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 solution added as catalyst, 34.3 g (0.25 mol) of 3-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 3-nitrotoluene reaction was confirmed by LC, and the condensation solution was obtained.

[0133] 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 mixture was heated to 75 °C and pressurized to 1.5 MPa. LC confirmed that the reduction of nitro and nitroso compounds was complete. The organic phase was then filtered, washed with water, and subjected to vacuum distillation (-0.1 MPa, 170 °C) to remove light components, yielding 42.8 g of compound II-4 (approximately 80% yield). GC analysis revealed a 98% content. The compound was a pale yellow solid at room temperature.

[0134] [ka]

[0135] 1 H NMR (400 MHz, CDCl3) δ 7.09 (d, J = 7.3 Hz, 1H), 6.99 (t, J = 7.7 Hz, 1H), 6.91 (d, J = 8.2 Hz, 1H), 6.69 (t, J = 7.3 Hz, 1H), 6.55 (s, 1H), 6.49 (dd, J= 14.3, 5.2 Hz, 2H), 4.91 (s, 1H), 3.48 (br s, 2H), 2.23 (s, 3H), 2.11 (s, 3H). 13 C NMR (101 MHz, CDCl3) δ 144.96, 143.28, 134.47, 131.88, 130.36, 126.83, 126.36, 123.02, 118.25, 117.60, 113.65, 113.07, 17.90, 17.62.

[0136] (ii) Synthesis of Compound I-4 42.8g (0.2mol) of compound II-4, 156.8g (1.6mol) of cyclohexanone, and 0.5g of Pt / C catalyst were added to a reactor and purged with hydrogen gas three times. The reaction was then heated to 100°C and hydrogen gas was passed through at 1.5MPa. GC analysis confirmed that the compound II-4 content was <0.1%. The reaction was then terminated. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by vacuum distillation at -0.1MPa and 180°C to obtain 59.6g of compound I-4 (yield approximately 99.5%). GC analysis showed a content of >98.2%. The product was a dark brown liquid at room temperature.

[0137] [ka]

[0138] 1 H NMR (400 MHz, CDCl3) δ 7.17 (d, J = 7.3 Hz, 1H), 7.10 - 7.04 (m, 1H), 7.02 (d, J= 8.4 Hz, 1H), 6.76 (td, J = 7.3, 0.9 Hz, 1H), 6.60 - 6.56 (m, 2H), 6.51 (dd, J = 8.4, 2.7 Hz, 1H), 4.99 (s, 1H), 3.51 (s, 1H), 3.37 - 3.23 (m, 1H), 2.33 (s, 3H), 2.21 (s, 3H), 2.18 - 2.10 (m, 2H), 1.90 - 1.80 (m, 2H), 1.78 - 1.69 (m, 1H), 1.52 - 1.39 (m, 2H), 1.37 - 1.16 (m, 3H). 13 C NMR (101 MHz, CDCl3) δ 145.36, 144.83, 134.97, 130.30, 130.26, 127.05, 126.85, 122.56, 117.88, 115.60, 112.70 , 111.64, 52.10, 33.64, 26.00, 25.10, 18.12, 17.63.

[0139] [Example 5] Synthesis of Compound I-5 (N-1,3-dimethylbutyl-N'-2-methylphenyl-2-methyl-1,4-phenylenediamine) (i) Synthesis of Compound II-4 The synthesis of compound II-4 is the same as in Example 4.

[0140] (ii) Synthesis of Compound I-5 43.2g (0.2mol) of compound II-4, 160.3g (1.6mol) of 4-methyl-2-pentanone, and 0.5g of Pt / C catalyst were added to a reactor. After purging with hydrogen gas three times, the reaction was heated to 100°C and hydrogen gas was passed through at 1.5MPa. GC analysis confirmed that the compound II-2 content was <0.1%. The reaction was then terminated. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by vacuum distillation at -0.1MPa and 180°C to obtain 59.6g of compound I-3 (yield approximately 99.5%). GC analysis showed a content of >98.2%. The product was a deep red liquid at room temperature.

[0141] [ka]

[0142] 1 H NMR (400 MHz, CDCl3) δ 7.15 (d, J = 7.3 Hz, 1H), 7.08 - 7.03 (m, 1H), 7.01 (d, J= 8.4 Hz, 1H), 6.74 (td, J = 7.3, 1.0 Hz, 1H), 6.59 - 6.53 (m, 2H), 6.49 (dd, J = 8.4, 2.7 Hz, 1H), 4.97 (s, 1H), 3.65 - 3.51 (m, 1H), 3.21 (br s, 1H), 2.31 (s, 3H), 2.19 (s, 3H), 1.90 - 1.75 (m, 1H), 1.59 - 1.47 (m, 1H), 1.38 - 1.28 (m, 1H), 1.22 (d, J = 6.2 Hz, 3H), 1.01 (d, J = 6.6 Hz, 3H), 0.99 (d, J = 6.6 Hz, 3H). 13C NMR (101 MHz, CDCl3) δ 145.40, 145.20, 135.03, 130.35, 130.23, 127.11, 126.90, 122.60, 117.92, 115.55, 112.76, 111.53, 47.09, 46.93, 25.19, 23.08, 22.68, 21.23, 18.18, 17.67.

[0143] [Example 6] Synthesis of Compound I-6 (N-Cyclohexyl-N'-4-methylphenyl-2-methyl-1,4-phenylenediamine) (i) Synthesis of Compound II-6 A 500 mL four-neck flask was charged with 160.5 g (1.5 mol) of 4-methylaniline and 100.1 g (0.275 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 4-methylaniline formed a salt. 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 solution added as a catalyst, 34.3 g (0.25 mol) of 3-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 3-nitrotoluene reaction was confirmed by LC, and the condensed solution was obtained.

[0144] 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 mixture was heated to 75 °C and pressurized to 1.5 MPa. LC confirmed that the reduction of nitro and nitroso compounds was complete. The organic phase was then filtered, washed with water, and subjected to vacuum distillation (-0.1 MPa, 170 °C) to remove light components, yielding 46.1 g of compound II-6 (approximately 86% yield). GC analysis revealed a 98% content. The compound was a pale yellow solid at room temperature.

[0145] [ka]

[0146] 1 H NMR (400 MHz, CDCl3) δ 7.01 (t, J = 6.6 Hz, 3H), 6.67 - 6.63 (m, 2H), 6.62 (d, J= 2.5 Hz, 1H), 6.55 (dd, J = 8.3, 2.6 Hz, 1H), 5.02 (s, 1H), 3.38 (s, 2H), 2.29 (s, 3H), 2.19 (s, 3H). 13 C NMR (101 MHz, CDCl3) δ 144.36, 142.87, 133.94, 132.41, 129.72, 127.73, 125.32, 117.69, 114.90, 113.67, 20.47, 17.99.

[0147] (ii) Synthesis of Compound I-6 42.8g (0.2mol) of compound II-6, 156.8g (1.6mol) of cyclohexanone, and 0.5g of Pt / C catalyst were added to a reactor and purged with hydrogen gas three times. The reaction was then heated to 100°C and hydrogen gas was passed through at 1.5MPa. GC analysis confirmed that the compound II-6 content was <0.1%. The reaction was then terminated. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by vacuum distillation at -0.1MPa and 180°C to obtain 59.6g of compound I-6 (yield approximately 99.5%). GC analysis showed a content of >98.2%. The product was a dark brown liquid at room temperature.

[0148] [ka]

[0149] 1H NMR (400 MHz, CDCl3) δ 6.99 (t, J = 8.2 Hz, 3H), 6.60 (d, J = 8.4 Hz, 2H), 6.51 (d, J = 2.5 Hz, 1H), 6.45 (dd, J = 8.4, 2.7 Hz, 1H), 5.04 (s, 1H), 3.40 (s, 1H), 3.29 - 3.17 (m, 1H), 2.26 (s, 3H), 2.17 (s, 3H), 2.12 - 2.04 (m, 2H), 1.83 - 1.75 (m, 2H), 1.72 - 1.61 (m, 1H), 1.51 - 1.31 (m, 2H), 1.28 - 1.13 (m, 3H). 13 C NMR (101 MHz, CDCl3) δ 144.85, 144.56, 134.52, 130.81, 129.71, 127.39, 126.12, 115.71, 114.54, 111.69, 52.22, 33.70, 26.03, 25.12, 20.48, 18.22.

[0150] [Example 7] Synthesis of Compound I-7 (N-1,3-dimethylbutyl-N'-4-methylphenyl-2-methyl-1,4-phenylenediamine) (i) Synthesis of Compound II-6 The synthesis of compound II-6 is the same as in Example 6.

[0151] (ii) Synthesis of Compound I-7 43.2g (0.2mol) of compound II-6, 160.3g (1.6mol) of 4-methyl-2-pentanone, and 0.5g of Pt / C catalyst were added to a reactor. After purging with hydrogen gas three times, the reactor was heated to 100°C and hydrogen gas was passed through at 1.5MPa. GC analysis confirmed that the compound II-6 content was <0.1%. The reaction was then terminated. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by vacuum distillation at -0.1MPa and 180°C to obtain 59.6g of compound I-3 (yield approximately 99.5%). GC analysis showed a content of >98.2%. The product was a deep red liquid at room temperature.

[0152]

change

[0153] 1 H NMR (400 MHz, CDCl3) δ 6.96 (dd, J = 9.8, 8.6 Hz, 3H), 6.57 (d, J = 8.4 Hz, 2H), 6.46 (d, J = 2.3 Hz, 1H), 6.40 (dd, J = 8.4, 2.5 Hz, 1H), 4.98 (s, 1H), 3.58 - 3.40 (m, 1H), 3.25 (br s, 1H), 2.22 (s, 3H), 2.14 (s, 3H), 1.82 - 1.68 (m, 1H), 1.52 - 1.36 (m, 1H), 1.31 - 1.19 (m, 1H), 1.15 (d, J = 6.2 Hz, 3H), 0.94 (d, J = 6.6 Hz, 3H), 0.92 (d, J = 6.6 Hz, 3H). 13 C NMR (101 MHz, CDCl3) δ 144.92, 134.61, 130.72, 129.74, 127.34, 126.24, 115.60, 114.55, 111.51, 47.13, 46.99, 25.21, 23.10, 22.71, 21.26, 20.52, 18.27.

[0154] [Example 8] Synthesis of Compound I-8 (N-Cyclohexyl-N'-2,3-dimethylphenyl-2-methyl-1,4-phenylenediamine) (i) Synthesis of compound II-8 A 500 mL four-neck flask was charged with 181.5 g (1.5 mol) of 2.3-methylaniline and 100.1 g (0.275 mol) of 25% aqueous tetramethylammonium hydroxide (TMAOH). The mixture was heated to 40-50 °C with stirring and dehydrated by vacuum distillation to form the salt of 2.3-dimethylaniline with TMAOH. 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 solution added as catalyst, 34.3 g (0.25 mol) of 3-nitrotoluene was added dropwise at 72 °C under reduced pressure (-0.098 MPa) for approximately 3 hours. After completion of the dropwise addition, the mixture was kept at this temperature for 1 hour. The completion of the 3-nitrotoluene reaction was confirmed by LC, and the condensation solution was obtained.

[0155] 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 mixture was heated to 75 °C and pressurized to 1.5 MPa. LC confirmed that the reduction of nitro and nitroso compounds was complete. The organic phase was then filtered, washed with water, and subjected to vacuum distillation (-0.1 MPa, 180 °C) to remove light components, yielding 46.6 g of compound II-8 (approximately 80% yield). GC analysis revealed a content of >97%. After cooling, the mixture was a pale yellow solid.

[0156] [ka]

[0157] 1H NMR (400 MHz, CDCl3) δ 6.93 (t, J = 7.8 Hz, 1H), 6.88 (d, J = 8.3 Hz, 1H), 6.68 (d, J = 7.4 Hz, 1H), 6.62 (d, J = 2.1 Hz, 1H), 6.58 - 6.50 (m, 1H), 6.46 (d, J= 8.1 Hz, 1H), 4.95 (s, 1H), 3.53 (s, 2H), 2.33 (s, 3H), 2.19 (s, 3H), 2.16 (s, 3H). 13 C NMR (101 MHz, CDCl3) δ 144.73, 142.86, 137.04, 133.81, 132.84, 125.97, 125.55, 122.39, 120.95, 117.73, 113.75, 112.33, 20.72, 17.98, 12.99.

[0158] (ii) Synthesis of Compound I-8 46.6g (0.2mol) of compound II-8, 156.8g (1.6mol) of cyclohexanone, and 0.5g of Pt / C catalyst were added to a reactor and purged with hydrogen gas three times. The reaction was then heated to 100°C and hydrogen gas was passed through at 1.5MPa. GC analysis confirmed that the compound II-8 content was <0.1%. The reaction was then terminated. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by vacuum distillation at -0.1MPa and 180°C to obtain 65.9g of compound I-8 (yield approximately 99.5%). GC analysis showed a content of >97.6%. The compound was a red liquid at room temperature.

[0159] [ka]

[0160] 1H NMR (400 MHz, CDCl3) δ 7.02 - 6.86 (m, 2H), 6.68 (d, J = 7.4 Hz, 1H), 6.54 (d, J = 2.6 Hz, 1H), 6.51 - 6.41 (m, 2H), 4.96 (s, 1H), 3.51 (br s, 1H), 3.39 - 3.07 (m, 1H), 2.35 (s, 3H), 2.22 (s, 3H), 2.18 (s, 3H), 2.16 - 2.05 (m, 2H), 1.88 - 1.76 (m, 2H), 1.75 - 1.64 (m, 1H), 1.49 - 1.34 (m, 2H), 1.34 - 1.11 (m, 3H). 13 C NMR (101 MHz, CDCl3) δ 145.18, 144.54, 136.88, 134.42, 131.08, 126.40, 125.95, 121.69, 120.48, 115.72, 111.74, 52.21, 33.70, 26.04, 25.13, 20.71, 18.16, 12.90.

[0161] [Example 9] Synthesis of Compound I-9 (N-Isopropyl-N'-4-methylphenyl-2-methyl-1,4-phenylenediamine) (i) Synthesis of Compound II-8 The synthesis of compound II-8 is the same as in Example 8.

[0162] (ii) Synthesis of Compound I-9 46.6g (0.2mol) of compound II-8, 162.4g (2.8mol) of acetone, and 0.5g of Pt / C catalyst were added to a reactor and purged with hydrogen gas three times. The reaction was then heated to 70°C and hydrogen gas was passed through at 1.5MPa. GC analysis confirmed that the compound II-8 content was <0.1%. The reaction was then terminated. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by vacuum distillation at -0.1MPa and 180°C to obtain 54.9g of compound I-9 (yield approximately 99.5%). GC analysis showed a content of >97%. The compound was an off-white liquid at room temperature.

[0163]

change

[0164] 1 H NMR (400 MHz, CDCl3) δ 7.01 - 6.93 (m, 2H), 6.71 (d, J = 7.4 Hz, 1H), 6.57 (d, J = 2.6 Hz, 1H), 6.50 (dd, J = 8.3, 2.8 Hz, 2H), 4.99 (br s, 1H), 3.78 - 3.56 (m, 1H), 3.13 (br s, 1H), 2.38 (s, 3H), 2.24 (s, 3H), 2.21 (s, 3H), 1.28 (d, J = 6.3 Hz, 6H). 13 C NMR (101 MHz, CDCl3) δ 145.10, 144.59, 136.85, 134.30, 131.20, 126.28, 125.92, 121.71, 120.29, 115.81, 111.81, 111.78, 44.66, 23.15, 20.68, 18.13, 12.88.

[0165] [Example 10] Synthesis of Compound I-10 (N-Isopropyl-N'-2,3-dimethylphenyl-2,3-dimethyl-1,4-phenylenediamine) (i) Synthesis of compound II-10 A 500 mL four-neck flask was charged with 181.5 g (1.5 mol) of 2,3-dimethylaniline and 100.1 g (0.275 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 2,3-dimethylaniline were salted together, and 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 solution added, 37.8 g (0.25 mol) of 2,3-dimethylnitrobenzene was added dropwise at 72 °C under reduced pressure (-0.098 MPa) for approximately 3 hours. After the dropwise addition was complete, the mixture was kept at this temperature for 2 hours. The completion of the 2,3-dimethylnitrobenzene reaction was confirmed by LC, and the resulting condensate was obtained.

[0166] The condensed 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 mixture was heated to 75 °C and pressurized to 1.5 MPa. LC confirmed that the reduction of nitro and nitroso compounds was complete. The organic phase was then filtered, washed with water, and subjected to vacuum distillation (-0.1 MPa, 180 °C) to remove light components, yielding 47.5 g of compound II-10 (approximately 76% yield). GC analysis revealed a content of >96%. After cooling, the mixture was a pale yellow liquid.

[0167] [ka]

[0168] 1H NMR (400 MHz, CDCl3) δ 6.91 (t, J = 7.9 Hz, 1H), 6.87 (d, J = 8.3 Hz, 1H), 6.67 (d, J = 7.5 Hz, 1H), 6.58 (d, J = 8.2 Hz, 1H), 6.27 (d, J = 8.2 Hz, 1H), 4.93 (s, 1H), 3.52 (s, 2H), 2.35 (s, 3H), 2.21 (s, 3H), 2.18 (s, 3H), 2.16 (s, 3H).

[0169] (ii) Synthesis of Compound I-10 37.5g (0.15mol) of compound II-10, 162.4g (2.8mol) of acetone, and 0.5g of Pt / C catalyst were added to a reactor. After purging with hydrogen gas three times, the reaction was heated to 70°C and hydrogen gas was passed through at 1.5MPa. GC analysis confirmed that the compound II-10 content was <0.1%. The reaction was then terminated. The temperature was lowered, the catalyst was removed by filtration, and the light components were removed by vacuum distillation at -0.1MPa and 180°C to obtain 43.7g of compound I-10 (yield approximately 99.4%), which had a content of >96% by GC analysis. The product was an off-white liquid at room temperature.

[0170] [ka]

[0171] 1 H NMR (400 MHz, CDCl3) δ 6.90 (t, J = 7.7 Hz, 1H), 6.84 (d, J = 8.0 Hz, 1H), 6.57 (d, J = 7.5 Hz, 1H), 6.55 (d, J = 8.1 Hz, 1H), 6.23 (d, J = 8.1 Hz, 1H), 4.95 (s, 1H), 3.76 - 3.53 (m, 1H), 3.12 (s, 1H), 2.35 (s, 3H), 2.21 (s, 3H), 2.17 (s, 6H), 1.29 (d, J = 6.2 Hz, 6H).

[0172] [Test example] Based on the formulations shown in Table 1, rubber materials 1 to 4 were prepared in the following steps.

[0173] 1. Natural rubber SCR5 was placed in an internal mixer and mixed for a certain period of time. Then, carbon black N330, aroma oil, zinc oxide, stearic acid, and antioxidant (6PPD, compound I-1, compound I-2, or compound I-4) were added in that order, and mixing was continued until the mixture was uniformly mixed. The temperature during mixing was controlled within the range of 150°C to 160°C.

[0174] 2. After the whole mixture was cooled to below 100°C, the crosslinking system (sulfur S and accelerator CBS) was added and the whole mixture was kneaded, controlling the temperature during kneading so as not to exceed 110°C.

[0175] 3. The obtained rubber composition was rolled into a sheet (thickness: 2 to 3 mm) and vulcanized at 150°C for 15 minutes.

[0176] The suppliers of each material in Table 1 are as follows: SCR5: Xishuangbanna Sinochemical Rubber Co., Ltd. Natural Rubber SCR5 N330: Cabot Carbon Black N330 Stearic acid: Shanghai Titan Technology Co., Ltd. General reagent Stearic acid (AR) Zinc Oxide: Shanghai Titan Technology Co., Ltd. General Reagent Zinc Oxide (AR) CBS: Seio Chemical Technology Co., Ltd. Vulcanization Accelerator CBS S:Sinopharm Chemical Reagent Co., Ltd. Sublimated sulfur (AR) 6PPD: SIRANTOX 6PPD manufactured by Seio Chemical Technology Co., Ltd. Compound I-1: Compound synthesized in Example 1 Compound I-2: Compound synthesized in Example 2 Compound I-4: Compound synthesized in Example 4

[0177] [Table 1]

[0178] According to GB / T 16585, UV aging resistance tests were conducted on rubber materials 1 to 4 according to the test method for vulcanized rubber subjected to artificial weathering (fluorescent ultraviolet lamp). The test parameters and steps are shown in Table 2, and the test results are shown in Table 3.

[0179] Based on GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized or thermoplastic rubber, the physical properties (tensile strength and elongation at break) of rubber materials 1 to 4 were measured, and the results are shown in Table 3.

[0180] According to GB / T 3512-2014, vulcanized or thermoplastic rubber - Hot air accelerated aging and heat resistance test, oxidation aging tests were conducted on rubber materials 1 to 4 under the test conditions of 100°C x 48 hours. The test results are shown in Table 3.

[0181] [Table 2]

[0182] [Table 3]

[0183] The measurement results in Table 3 show that rubber materials 2 to 4 containing the antioxidant of the present invention are superior in both thermal oxidative aging resistance and UV aging resistance compared to rubber material 1 containing 6PPD. In terms of thermal oxidative aging resistance, after aging at 100°C for 48 hours, the property retention rates of rubber materials 2 to 4 are all improved by about 10% compared to rubber material 1. In terms of UV aging resistance, after aging for 168 hours according to the test conditions in Table 2, the property retention rates of rubber materials 2 to 4 are all improved by 5% or more compared to rubber material 1.

Claims

1. A compound of formula I, 【Chemistry 1】 In Formula I, each R 1 are each independently selected from H, a C1 to C18 chain hydrocarbon group, and a C3 to C18 alicyclic hydrocarbon group, and a is an integer of 1 to 5; R 2 , R 3 , R 4 , R 5 are each independently selected from H, a C1 to C18 chain hydrocarbon group, and a C3 to C18 alicyclic hydrocarbon group, and R 2 , R 3 , R 4 , R 5 At least one group is not H, R 6 , R 7 are each independently selected from a C1 to C18 chain hydrocarbon group and a C3 to C18 alicyclic hydrocarbon group, or R 6 and R 7 is a compound that forms a C3 to C18 aliphatic ring.

2. Each R 1 are each independently selected from H and a C1-C8 alkyl group, and a is an integer from 1 to 2; R 2 , R 3 , R 4 , R 5 are each independently selected from H and a C1-C8 alkyl group, and R 2 , R 3 , R 4 , R 5 Among these, 2-3 groups are H, R 6 , R 7 are each independently selected from C1 to C8 alkyl groups and C3 to C8 cycloalkyl groups, or R 6 and R 7 forms a C3-C8 aliphatic ring, 2. The compound of claim 1.

3. It includes the following steps: (1) A compound represented by formula A and a compound represented by formula B are subjected to a condensation reaction under the action of a first catalyst to obtain a condensate containing a compound represented by formula C and / or a compound represented by formula C', and then the condensate is subjected to H 2 and reducing the compound represented by formula II under the action of a second catalyst, 【Chemistry 2】 (2) The compound of formula II is reacted with the compound of formula D and H 2 and then subjecting the resulting compound to a reductive alkylation reaction under the action of a third catalyst to obtain a compound of formula I. A method for producing the compound of claim 1. 【Transformation 3】 (R in Formula A, Formula B, Formula C, Formula C', Formula D, Formula II and Formula I) 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 is the same as in claim 1)

4. The method according to claim 3, characterized in that it has one or more of the following characteristics: 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; 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 sieve; The third catalyst is a supported metal catalyst, and 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 molar ratio of the compound represented by formula A to the compound represented by formula B is 2:1 to 15:1, preferably 4:1 to 10:1; In step (1), the temperature of the condensation reaction is 40 to 90°C, preferably 65 to 85°C, and the degree of vacuum is -0.09 to -0.99 MPa; In step (1), the condensate and H 2 the reaction temperature is 40 to 120°C, preferably 60 to 90°C, and the hydrogen pressure is 0.5 to 5 MPa, preferably 0.5 to 2.5 MPa; In step (2), the molar ratio of the compound of formula D to the compound of formula II is 1:1 to 15:1; In step (2), the reaction temperature is 40 to 150°C, and the reaction pressure is 0.5 to 5 MPa.

5. A compound of formula II, 【Chemistry 4】 In Formula II, each R 1 are each independently selected from H, a C1 to C18 chain hydrocarbon group, and a C3 to C18 alicyclic hydrocarbon group, and a is an integer of 1 to 5; R 2 , R 3 , R 4 , R 5 are each independently selected from H, a C1 to C18 chain hydrocarbon group, and a C3 to C18 alicyclic hydrocarbon group, and R 2 , R 3 , R 4 , R 5 Compounds in which at least one group is not H.

6. Each R 1 are each independently selected from H and a C1-C8 alkyl group, and a is an integer from 1 to 2; R 2 , R 3 , R 4 , R 5 are each independently selected from H and a C1-C8 alkyl group, and R 2 , R 3 , R 4 , R 5 The compound according to claim 5, wherein two or three groups are H.

7. A compound represented by formula A and a compound represented by formula B are subjected to a condensation reaction under the action of a first catalyst to obtain a condensate containing a compound represented by formula C and / or a compound represented by formula C', and then the condensate is subjected to H 2 and reducing the compound represented by formula II under the action of a second catalyst to obtain the compound represented by formula II. 【Transformation 5】 (R in Formula A, Formula B, Formula C, Formula C' and Formula II) 1 , R 2 , R 3 , R 4 , R 5 is as described above)

8. 8. The method of claim 7, wherein the method has one or more of the following characteristics: 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; 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 sieve; In step (1), the molar ratio of the compound of formula A to the compound of formula B is 2:1 to 15:1, preferably 4:1 to 10:1; In step (1), the temperature of the condensation reaction is 40 to 90°C, preferably 65 to 85°C, and the degree of vacuum is -0.09 to -0.99 MPa; In step (1), the condensate and H 2 The reaction temperature is 40 to 120°C, preferably 60 to 90°C, and the hydrogen pressure is 0.5 to 5 MPa, preferably 0.5 to 2.5 MPa.

9. A rubber composition comprising the compound according to claim 1 or 2.

10. A rubber product comprising the rubber composition according to claim 9, preferably a tire.

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

3. A process comprising adding a compound according to claim 1 or 2 to rubber or a rubber product.

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