A three-arm branched hindered phenolic compound and a synthesis method and application thereof

Abstract

The application provides a three-arm branched hindered phenol compound and a synthesis method and application thereof. The application introduces a polar amide group in the structure of a synthesis product, increases the interaction between a polymer matrix and an antioxidant molecule in a polar polymer matrix, improves the migration resistance of the antioxidant, and effectively reduces the migration loss of the antioxidant during use.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of antioxidants and organic chemical synthesis, and particularly relates to a three-arm branched hindered phenol type compound, a synthesis method thereof and application of the three-arm branched hindered phenol type compound as an antioxidant in preparation of nylon. BACKGROUND

[0002] With the wide application of high molecular materials in daily production and life, deterioration or performance degradation inevitably occurs due to the effects of light, heat and oxygen. The main reason for this phenomenon is the occurrence of complex chemical reactions under the action of external environment. In actual production and application, high molecular materials are inevitably subjected to thermal oxidative aging when exposed to oxygen, high temperature, light, water and other external environments, which leads to the decline of the comprehensive performance of the materials and shortens the service life. By introducing antioxidants during processing, the above-mentioned situations can be effectively alleviated. Hindered phenolic antioxidants have good antioxidant effect, high thermal stability, small coloring property to products and other advantages. However, the varieties of commercially available antioxidants are relatively single, and most of them have poor compatibility with the high molecular matrix. For nylon materials with high melting point, the thermal stability of the hindered phenolic antioxidants cannot meet the processing conditions, and they also face the problem of not being resistant to migration during long-term use. Hindered phenolic antioxidants usually need to be generated through ester exchange under the action of an alkaline catalyst. Related reports US4716244, US5481023, US5563291, US6878843, US2003166962, WO198249, CN101215235B and CN102432870B respectively describe the processes for preparing hindered phenolic antioxidants using different catalysts. However, the main problems are that the reaction process and post-treatment are complex, the energy consumption is high, the technical barriers are high, and it is difficult to realize industrialized production. SUMMARY

[0003] In order to solve the above-mentioned problems, the present inventors have designed and synthesized a three-arm branched hindered phenol type antioxidant from the structure of nylon materials. The present application adopts a simple method to synthesize the three-arm branched hindered phenol type antioxidant. The product yield of the method is high, the product is easy to purify, and the product has the dual effects of amine and hindered phenol antioxidants, high antioxidant efficiency, and is expected to realize industrialized production.

[0004] The purpose of the present application is to provide a three-arm branched hindered phenol type compound, a synthesis method thereof and application thereof.

[0005] To achieve the above-mentioned purposes, the technical solutions adopted by the present application are as follows:

[0006] In a first aspect, the present application provides a three-arm branched hindered phenol type compound represented by formula 5,

[0007]

[0008] R2 is -(CH2)n-Ph, wherein n is an integer between 2 and 6. n or phenyl, wherein n is an integer between 2 and 6.

[0009] Preferably, the tri-armed branched hindered phenolic compound is one of the following:

[0010]

[0011]

[0012] The tri-armed branched hindered phenolic compound of formula I is particularly preferred.

[0013] In a second aspect, the present application provides a method for synthesizing the tri-armed branched hindered phenolic compound of formula 5, the method comprising:

[0014] S1: dissolving a compound of formula 1 in methanol, under a protective atmosphere A (in one embodiment of the present application, the protective atmosphere is nitrogen atmosphere), adding a compound of formula 2, carrying out a first stage reaction at 0-5°C for 30-60 min (preferably 30 min), increasing the temperature to 25-30°C, carrying out a second stage reaction for 12-24 h (preferably a second stage reaction at 25°C for 24 h), and separating and purifying the obtained reaction solution to obtain a compound of formula 3; the molar ratio of the compound of formula 1 to the compound of formula 2 is 1:3.5-6 (preferably 1:6);

[0015]

[0016] S2: dissolving the compound of formula 3 obtained in step S1, a compound of formula 4 and a strong base in an organic solvent, under a protective atmosphere B (in one embodiment of the present application, the protective atmosphere is nitrogen atmosphere), stirring and reacting at 100-120°C for 6-12 h (preferably stirring and reacting at 100°C for 6 h), and carrying out post-treatment on the obtained reaction mixture to obtain the tri-armed branched hindered phenolic compound of formula 5; the molar ratio of the compound of formula 4 to the compound of formula 3 is 3-4:1 (preferably 4.3:1); the molar ratio of the compound of formula 4 to the strong base is 1:1-5 (preferably 1:1);

[0017]

[0018] In formulae 1, 2, 3 and 5, R1 is hydroxyl or C1-C4 alkoxy, such as methoxy or ethoxy, and preferably R1 is methoxy.

[0019] R2 is -(CH2)n-Ph, wherein n is an integer between 2 and 6. n or phenyl, wherein n is an integer between 2 and 6; preferably the compound of formula 2 is p-phenylenediamine or ethylenediamine, and most preferably ethylenediamine.

[0020] R3 is hydroxyl or C1-C4 alkoxy, and preferably R3 is hydroxyl.

[0021] Further, the volume of the methanol in step S1 is 5-10 L / mol (preferably 10 L / mol) based on the amount of substance of the compound of formula 1.

[0022] Further, the separation and purification in step S1 is: rotary evaporation of the reaction solution, washing with a mixed solvent of methanol and toluene in a volume ratio of 1:10-15 (it is recommended to rotary evaporate for more than three times at 40-60°C to remove methanol), and drying to obtain the compound of formula 3.

[0023] Preferably, in step S2, the organic solvent is a mixed solvent of one or both of toluene and xylene, and most preferably toluene.

[0024] Further, the volume of the organic solvent in step S2 is 100-200 mL / g (preferably 200 mL / g) based on the mass of the compound of formula 3.

[0025] Further, the post-treatment in step S2 is: filtering the reaction mixture, and drying the obtained filter cake to obtain the three-arm branched hindered phenol type compound of formula 5.

[0026] Further, in step S2, the strong base is one or a mixture of two or more of sodium hydroxide, potassium hydroxide, lithium chloride, and sodium methoxide; and in an embodiment of the present application, it is sodium hydroxide.

[0027]

[0028] In a third aspect, the present application provides the use of the above-mentioned three-arm branched hindered phenol type compound in the preparation of a high molecular antioxidant.

[0029] Further, the use is: adding the three-arm branched hindered phenol type antioxidant to a high molecular material by melt blending to obtain a product. Further, the mass of the three-arm branched hindered phenol type antioxidant is 0.1-1 wt% based on the total mass of the three-arm branched hindered phenol type antioxidant and the nylon.

[0030] Further, the high molecular material is nylon, and preferably, the nylon is PA6.

[0031] More specifically, the use is: adding the three-arm branched hindered phenol type antioxidant to the nylon by one of the following methods:

[0032] (1) mixing a composition amount of the three-arm branched hindered phenol type antioxidant with the nylon uniformly by a torque rheometer, and placing it in a flat vulcanizing machine at 230-250°C to prepare the desired product;

[0033] (2) melt-extruding and granulating the nylon and the three-arm branched hindered phenol antioxidant in a group formula amount on a twin-screw extruder, drying the extruded granules in a vacuum oven (80-110 DEG C) for 4-16 hours, and then injection molding into a desired product.

[0034] The process of oxidation of high molecular material is a free radical autoxidation chain reaction process, and polymer material is inevitably affected by external factors such as temperature and light during processing and use to produce aging, and high-activity free radicals R· and ROO· are produced, which can react with polymer or oxygen to generate new free radicals. In the aging process, on the one hand, with the formation of peroxide and other oxygen-containing groups on the polymer chain, the macromolecular chain is broken; on the other hand, the random termination of chain free radicals will cause the crosslinking of the polymer, so that the molecular weight is increased, and an irregular network structure is formed. At the same time, the accumulation of various carbonyl compounds produced in the aging process will also cause the change of the color of the material. These phenomena will limit the further use of the material. Adding an antioxidant in the processing of the material can effectively prolong the time of the occurrence of the above-mentioned conditions. The antioxidant is divided into primary antioxidant and auxiliary antioxidant according to the different stages of capturing free radicals. The primary antioxidant mainly captures free radicals, and the auxiliary antioxidant mainly decomposes hydroperoxide. The primary antioxidant mainly includes hindered phenol type and arylamine type electron donors. The amine antioxidant mostly makes the product have color, so that its application field is limited to a certain extent. The hindered phenol antioxidant has the advantages of no pollution and no discoloration, and is widely used in the current market. The hindered phenol structure refers to the introduction of a tert-butyl group or other electron-donating substituents with steric hindrance effect at the position of the phenolic hydroxyl group. There is generally a large alkyl long chain in the molecule of the antioxidant. The alkyl long chain itself is rich in electrons, and acts as an electron donor in the whole structure, so that the H on the phenolic antioxidant -OH is easily taken away by ROO· produced in the oxidation process, and ROO· becomes ROOH after taking away H, and plays a role in stabilizing free radicals. The existence of these groups, on the one hand, improves the electron cloud density in the phenoxy radical conjugated system, and endows it with chemical activity, so as to provide active hydrogen atoms in the process of polymer stabilization, capture free radicals that initiate polymer oxidation and aging, and on the other hand, the hindered phenol can make the charge of the free radical formed after the departure of H tend to be averaged under the action of the conjugated structure due to the existence of a large benzene ring and a conjugated structure, and form a low-activity and high-stability free radical through the transformation between the conjugated structures, thereby preventing further attack on the molecular chain.

[0035] In the application, the preferred trimellitic acid trimethyl ester is used as a branched center, and the hindered phenol structure is combined with the branched center trimellitic acid trimethyl ester through a chemical bond by using ethylenediamine. The carbonyl group connected with the ethylenediamine belongs to an electron-withdrawing group, and under the double action of the benzene ring and the carbonyl group, it is easier to form a stable N -The negative ion can realize the dual effects of the amine antioxidant and the hindered phenol antioxidant, and the branched structure can provide more potential hydrogen bond sites due to the amide structure, thereby effectively solving the problem of poor migration resistance in some polar polymer matrix.

[0036] Compared with the prior art, the amide group is introduced into the structure of the synthetic product, the interaction between the polymer matrix and the antioxidant molecules is increased in the polar polymer matrix, the migration resistance of the antioxidant is improved, and the migration loss of the antioxidant during use is effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The infrared spectrum of the product structure of example 1

[0038] Figure 2 The nuclear magnetic resonance hydrogen spectrum of the product structure of example 1 DETAILED DESCRIPTION

[0039] In order to more clearly illustrate the present application, the present application will be further described below in combination with preferred embodiments. It should be understood by those skilled in the art that the specific description below is illustrative rather than limiting, and should not limit the protection scope of the present application;

[0040] Unless otherwise specified, the purity of the products involved in the present application is greater than 95%.

[0041] Example 1

[0042] ① 2.52 g (0.01 mol) of trimethylbenzene-1,3,5-tricarboxylate was dissolved in 100 ml of methanol, 3.6 ml (0.06 mol) of ethylenediamine was added under nitrogen protection, and the reaction was carried out at 0-5℃ for 30 min, then the temperature was raised to 25℃, and the reaction was continued for 24 h. The solvent was removed by rotary evaporation, and the excess ethylenediamine was removed by washing with a mixture of methanol and toluene (v / v 1:10) several times. The product was dried at 60℃ for standby.

[0043] ② 1 g (0.003 mol) of the target product obtained above, 3.31 g (0.013 mol) of 3.5-di-tert-butyl-4-hydroxyphenylpropionic acid, and 0.5 g (0.013 mol) of NaOH were sequentially added to a three-necked flask, dissolved in 200 ml of toluene under magnetic stirring, and heated to 100℃. The reaction was carried out under nitrogen protection for 6 h. After the reaction was completed, the solvent and excess 3.5-di-tert-butyl-4-hydroxyphenylpropionic acid were removed by filtration, and the product was dried at 60℃ to obtain 2.89 g of the target product with a slight yellow color, with a yield of 86.4%.

[0044] The target product prepared in this example was detected by infrared spectrometer and nuclear magnetic resonance spectrometer. The absorption peak at 3600 cm-1 was the absorption peak of -OH on benzene ring, the absorption peak at 3300-3200 cm-1 was the stretching vibration absorption peak of -NH-, the absorption peak at 2870-2960 cm-1 belonged to the stretching vibration of -CH3 and -CH2, and the absorption peak at 1539 cm-1 was the bending vibration absorption peak of -NH-. Figure 1

[0045] 1 H NMR 400MHz, DMSO-d6, δ = 9.01-9.86 (t, 6H, h) ppm, δ = 8.72-8.754 (m, 3H, g) ppm, δ = 6.72-6.89 (s, 6H, f) ppm, δ = 6.68-6.70 (s, 3H, e) ppm, δ = 3.57-3.70 (t, 12H, d) ppm, δ = 2.50-2.88 (t, 6H, c) ppm, δ = 2.30-2.34 (t, 6H, b) ppm, δ = 1.30-1.37 (s, 54H, a) ppm, thereby proving the structure of the product molecule. Figure 2

[0046] The application method of the above three-arm branched hindered phenolic antioxidant in nylon 6 is as follows:

[0047] ①The above obtained 0.4wt% three-arm branched hindered phenolic antioxidant and 99.6wt% PA6 treated in a vacuum oven at 110℃ for more than 4 hours were uniformly mixed by using a torque rheometer, and then plastic tensile test standard samples were prepared in a flat vulcanizing machine at 230℃. The tensile test standard samples were prepared according to GB / T1040.2-2006.

[0048] ②The tensile strength of the above samples was tested after aging at 150℃ in a blast drying oven for 400h, so as to evaluate the performance of resisting thermal oxidative aging.

[0049] Example 2:

[0050] ①2.52g (0.01mol) of trimellitic acid trimethyl ester was dissolved in 100ml of methanol, 3.6ml (0.06mol) of ethylenediamine was added under nitrogen protection, and the reaction was carried out at 0-5℃ for 30min, then the temperature was increased to 25℃, and the reaction was continued for 24h. The solvent was removed by using a rotary evaporator, and the excess ethylenediamine was removed by using a rotary evaporator. The product was dried at 60℃ and was ready for use.

[0051] ​​① 2.52 g (0.01 mol) of trimethyl trimellitate was dissolved in 100 ml of methanol, 4.3 ml (0.037 mol) of p-phenylenediamine was added under nitrogen protection, and the reaction was carried out at 0-5°C for 30 min, then the temperature was raised to 25°C, and the reaction was continued for 24 h. The solvent was removed by rotary evaporation at 40-60°C, and the excess p-phenylenediamine was removed by washing with a mixture of methanol and toluene (v / v 1:10) several times. The product was dried at 60°C and stored for use.

[0052] The application method of the above-mentioned three-arm branched hindered phenolic antioxidant in nylon 6 is as follows:

[0053] ① 0.4 wt% of the above-mentioned three-arm branched hindered phenolic antioxidant was mixed with 99.6 wt% of PA6 treated in a vacuum oven at 110°C for more than 4 h by using a torque rheometer, and then the mixture was placed in a flat vulcanizing machine at 230°C to obtain a plastic tensile test standard sample. The tensile test standard sample was prepared according to GB / T1040.2-2006.

[0054] ② The tensile strength of the sample was tested after aging at 150°C in a blast drying oven for 400 h, so as to evaluate the resistance to thermal oxidative aging.

[0055] Example 3:

[0056] ① 2.52 g (0.01 mol) of trimethyl trimellitate was dissolved in 100 ml of methanol, 4.3 ml (0.037 mol) of p-phenylenediamine was added under nitrogen protection, and the reaction was carried out at 0-5°C for 30 min, then the temperature was raised to 25°C, and the reaction was continued for 24 h. The solvent was removed by rotary evaporation at 40-60°C, and the excess p-phenylenediamine was removed by washing with a mixture of methanol and toluene (v / v 1:10) several times. The product was dried at 60°C and stored for use.

[0057] ② 1 g (0.0026 mol) of the above-mentioned target product, 3.31 g (0.013 mol) of 3.5-di-tert-butyl-4-hydroxyphenyl propionic acid, and 0.5 g (0.013 mol) of NaOH were sequentially added to a three-necked flask, and dissolved by magnetic stirring with 200 ml of toluene. The temperature was raised to 100°C, and the reaction was carried out under nitrogen protection for 6 h. After the reaction was completed, the solvent and excess 3.5-di-tert-butyl-4-hydroxyphenyl propionic acid were removed by filtration, and the product was dried at 60°C to obtain a slightly yellow target product 2.27 g with a yield of 74.8%.

[0058] The application method of the above-mentioned three-arm branched hindered phenolic antioxidant in nylon 6 is as follows:

[0059] ① The 0.4wt% three-arm branched hindered phenolic antioxidant obtained above was mixed uniformly with 99.6wt% PA6 treated in a vacuum oven at 110°C for more than 4 hours, and then placed in a flat vulcanizing machine at 230°C to obtain a plastic tensile test standard sample. The tensile test standard sample was prepared according to GB / T1040.2-2006.

[0060] ② The tensile strength of the sample was tested after aging at 150°C in a blast drying oven for 400h, so as to evaluate the resistance to thermal oxidative aging.

[0061] Example 4:

[0062] ① 2.52g (0.01mol) of trimethyl trimellitate was dissolved in 100ml of methanol, and 4.3ml (0.037mol) of p-phenylenediamine was added under nitrogen protection. After reaction at 0-5°C for 30min, the temperature was raised to 25°C, and the reaction was continued for 24h. The solvent was removed by rotary evaporation under the condition of 40-60°C, and the excess p-phenylenediamine was removed by washing with a mixed solvent of methanol and toluene (v / v 1:10) for multiple times. The product was dried at 60°C for standby use.

[0063] ② The target product obtained above, 1g (0.0026mol), 3.48g (0.013mol) of 3.5-di-tert-butyl-4-hydroxyphenyl propionate methyl ester, and 0.5g (0.013mol) of NaOH were sequentially added into a three-necked flask, and dissolved by stirring with a magnet under the condition of 200ml of toluene and 100°C. The reaction was carried out under nitrogen protection for 6h. After the reaction was completed, the solvent and excess 3.5-di-tert-butyl-4-hydroxyphenyl propionate methyl ester were removed by filtration, and the product was dried at 60°C to obtain 2.24g of the target product with a yellowish color, with a yield of 73.9%.

[0064] The application method of the three-arm branched hindered phenolic antioxidant in nylon 6 is as follows:

[0065] ① The 0.4wt% three-arm branched hindered phenolic antioxidant obtained above was mixed uniformly with 99.6wt% PA6 treated in a vacuum oven at 110°C for more than 4 hours, and then placed in a flat vulcanizing machine at 230°C to obtain a plastic tensile test standard sample. The tensile test standard sample was prepared according to GB / T1040.2-2006.

[0066] ② The tensile strength of the sample was tested after aging at 150°C in a blast drying oven for 400h, so as to evaluate the resistance to thermal oxidative aging.

[0067] Example 5:

[0068] ① 2.10 g (0.01 mol) of trimesic acid was dissolved in 100 ml of methanol, 3.6 ml (0.06 mol) of ethylenediamine was added under nitrogen protection, and the reaction was carried out at 0-5°C for 30 min, then the temperature was raised to 25°C, and the reaction was continued for 24 h. The solvent was removed by rotary evaporation at 40-60°C, and the excess ethylenediamine was removed by washing with a mixture of methanol and toluene (v / v 1:10) several times. The product was dried at 60°C for standby use.

[0069] ② The target product obtained above was added into a three-necked flask, followed by 3.31 g (0.013 mol) of 3.5-di-tert-butyl-4-hydroxyphenylpropionic acid and 0.5 g (0.013 mol) of NaOH. The mixture was dissolved in 200 ml of toluene and stirred magnetically, and the temperature was raised to 100°C. The reaction was carried out under nitrogen protection for 6 h. After the reaction was completed, the solvent and excess 3.5-di-tert-butyl-4-hydroxyphenylpropionic acid were removed by filtration, and the product was dried at 60°C to obtain 2.56 g of the target product with a slight yellow color, with a yield of 76.5%.

[0070] The application method of the above-mentioned three-arm branched hindered phenolic antioxidant in nylon 6 is as follows:

[0071] ① The above-mentioned 0.4 wt% three-arm branched hindered phenolic antioxidant was mixed with 99.6 wt% PA6 treated in a vacuum oven at 110°C for more than 4 h to obtain a plastic tensile test standard sample by using a torque rheometer at 230°C. The tensile test standard sample was prepared according to GB / T1040.2-2006.

[0072] ② The tensile strength of the above-mentioned sample was tested after aging at 150°C for 400 h, so as to evaluate the performance of resistance to thermal oxidative aging.

[0073] Example 6:

[0074] ① 2.10 g (0.01 mol) of trimesic acid was dissolved in 100 ml of methanol, 3.6 ml (0.06 mol) of ethylenediamine was added under nitrogen protection, and the reaction was carried out at 0-5°C for 30 min, then the temperature was raised to 25°C, and the reaction was continued for 24 h. The solvent was removed by rotary evaporation at 40-60°C, and the excess ethylenediamine was removed by washing with a mixture of methanol and toluene (v / v 1:10) several times. The product was dried at 60°C for standby use.

[0075] The target product 1 g (0.003 mol), 3.48 g (0.013 mol) 3.5-di-tert-butyl-4-hydroxyphenyl propionic acid methyl ester and 0.5 g (0.013 mol) NaOH are sequentially added into a three-neck flask, dissolved by stirring with a magnet in 200 ml of toluene, heated to 100°C, and reacted for 6 hours under nitrogen protection. After the reaction is completed, the solvent and excess 3.5-di-tert-butyl-4-hydroxyphenyl propionic acid methyl ester are removed by filtration, and the target product 2.52 g with a slight yellow color is obtained by drying at 60°C, with a yield of 75.4%.

[0076] The application method of the three-arm branched hindered phenolic antioxidant in PA6 is as follows:

[0077] The 0.4 wt% three-arm branched hindered phenolic antioxidant obtained above and 99.6 wt% PA6 treated in a vacuum oven at 110°C for more than 4 hours are uniformly mixed by using a torque rheometer, and then placed in a flat vulcanizing machine at 230°C to obtain a plastic tensile test standard sample. The tensile test standard sample is prepared according to GB / T1040.2-2006.

[0078] After the sample is aged in a blast drying oven at 150°C for 400 hours, the tensile strength is tested to evaluate the resistance to thermal oxidative aging.

[0079] Example 7:

[0080] The 2.10 g (0.01 mol) of trimesic acid is dissolved in 100 ml of methanol, and 4.3 ml (0.037 mol) of p-phenylenediamine is added under nitrogen protection. After reaction for 30 min in an ice water bath at 0-5°C, the temperature is increased to 25°C, and the reaction is continued for 24 h. The solvent is removed by using a rotary evaporator, and the excess p-phenylenediamine is removed by washing with a mixed solvent of methanol and toluene (v / v 1:10) for multiple times. The product is dried at 60°C for standby use.

[0081] The target product 1 g (0.0026 mol), 3.31 g (0.013 mol) 3.5-di-tert-butyl-4-hydroxyphenyl propionic acid, and 0.5 g (0.013 mol) NaOH are sequentially added into a three-neck flask, dissolved by stirring with a magnet in 200 ml of toluene, heated to 100°C, and reacted for 6 hours under nitrogen protection. After the reaction is completed, the solvent and excess 3.5-di-tert-butyl-4-hydroxyphenyl propionic acid are removed by filtration, and the target product 2.21 g with a slight yellow color is obtained by drying at 60°C, with a yield of 72.8%.

[0082] The application method of the three-arm branched hindered phenolic antioxidant in PA6 is as follows:

[0083] ① The 0.4wt% three-arm branched hindered phenolic antioxidant obtained above was mixed uniformly with 99.6wt% PA6 treated in a vacuum oven at 110°C for more than 4 hours, and then placed in a flat vulcanizing machine at 230°C to obtain a plastic tensile test standard sample. The tensile test standard sample was prepared according to GB / T1040.2-2006.

[0084] ② The tensile strength of the sample was tested after aging at 150°C in a blast drying oven for 400h, so as to evaluate the resistance to thermal oxidative aging.

[0085] Example 8:

[0086] ① 2.10g (0.01mol) of trimesic acid was dissolved in 100ml of methanol, and 4.3ml (0.037mol) of p-phenylenediamine was added under nitrogen protection. After reaction for 30min in an ice water bath at 0-5°C, the temperature was raised to 25°C, and the reaction was continued for 24h. The solvent was removed by rotary evaporation under the condition of 40-60°C, and the excess p-phenylenediamine was removed by washing with a mixed solvent of methanol and toluene (v / v 1:10) for multiple times. The product was dried at 60°C for standby use.

[0087] ② The target product 1g (0.0026mol) obtained above, 3.48g (0.013mol) of 3.5-di-tert-butyl-4-hydroxyphenyl propionic acid methyl ester, and 0.5g (0.013mol) of NaOH were sequentially added into a three-necked flask, and dissolved by stirring with a magnet under 200ml of toluene. The temperature was raised to 100°C, and the reaction was carried out under nitrogen protection for 6h. After the reaction was completed, the solvent and excess 3.5-di-tert-butyl-4-hydroxyphenyl propionic acid methyl ester were removed by filtration, and the product was dried at 60°C to obtain 2.15g of the target product with a slight yellow color, with a yield of 70.8%.

[0088] The application method of the three-arm branched hindered phenolic antioxidant in nylon 6 is as follows:

[0089] ① The 0.4wt% three-arm branched hindered phenolic antioxidant obtained above was mixed uniformly with 99.6wt% PA6 treated in a vacuum oven at 110°C for more than 4 hours, and then placed in a flat vulcanizing machine at 230°C to obtain a plastic tensile test standard sample. The tensile test standard sample was prepared according to GB / T1040.2-2006.

[0090] ② The tensile strength of the sample was tested after aging at 150°C in a blast drying oven for 400h, so as to evaluate the resistance to thermal oxidative aging.

[0091] Comparative Example:

[0092] ①The 0.4wt% antioxidant 1098 was mixed with 99.6wt% PA6 treated by vacuum oven 110℃ for 4 hours to form a mixture, and then the mixture was placed in a flat vulcanizing machine at 230℃ to form a plastic tensile test standard sample. The tensile test standard sample was prepared according to GB / T1040.2-2006.

[0093] ②The tensile strength of the sample was tested after aging for 400 hours in a 150℃ air drying oven, so as to evaluate the resistance to thermal oxidative aging.

[0094] Result analysis:

[0095]

[0096]

[0097] In the examples 1-8, different structures of formula 1, formula 2 and formula 4 were used. It can be seen that when ethylenediamine is selected as formula 2, the yield of the final product is higher than that of p-phenylenediamine. This is because the reactivity of p-phenylenediamine is lower than that of ethylenediamine due to the influence of the structure of p-phenylenediamine. By comparing the examples 1 and 5, and the examples 2 and 6, when formula 2 and formula 4 are the same, the yield of formula 1 as trimethyl trimesate is higher than that as trimesate. This is because in the first step of synthesis, the carboxylic acid is directly connected to the benzene ring. Since the benzene ring can act as an electron-withdrawing group or an electron-deficient group, when it is directly connected to the carboxyl group, it behaves as a weak electron-donating group. Without a catalyst, the reactivity is limited, and the reaction with the diamine structure of formula 2 is limited. When the benzene ring is connected to the ester group, both the alkoxyl group and the benzene ring act as electron-donating groups, making the ester bond easy to break. After breaking, it is easy to react with the diamine structure of formula 2 to form an amide bond. Similarly, when formula 1 and formula 2 are the same, the reactivity of 3,5-di-tert-butyl-4-hydroxyphenyl propionate methyl ester is lower than that of 3,5-di-tert-butyl-4-hydroxyphenyl propionic acid. This is because when the carboxyl group is away from the influence of the benzene ring, the reactivity of the carboxyl group is greatly enhanced. Therefore, the examples 1 and 5 show higher yield than the examples 2 and 6.

[0098] The in vitro DPPH free radical scavenging ability of the synthesized antioxidant, the tensile strength retention rate after aging for 400 hours, and the commonly used commercial antioxidant AO 1098 (N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine) of the nylon matrix were compared. It can be seen that the synthesized antioxidant and the commercial antioxidant both have good scavenging effect on DPPH free radicals. Under the experimental conditions, the concentration (IC 50 ) value of AO 1098 for scavenging 50% DPPH free radicals is 8.31 mg / mL, and the concentration (IC 50) is 1.12-1.14 mg / mL, and the concentration (IC50) for eliminating 50% DPPH free radicals of Examples 3, 4, 7 and 8 is 1.12-1.14 mg / mL. 50 ) is 2.13-2.16 mg / mL, and Examples 1, 2, 5 and 6 exhibit excellent free radical capture ability within the same test time.

[0099] As can be seen from the data in the table, the tensile strength of Examples 1-8 and the comparative examples all decreases after aging for 400 h, but the retention rate of the tensile strength of the PA6 composite material after adding the synthetic antioxidant of the application is higher than that of the commercially available antioxidant 1098, which proves the excellent effect of the synthetic antioxidant of the application in the nylon matrix. When the formula 2 is a p-phenylenediamine structure, the effective component for playing an antioxidant role is lower than that of the antioxidant with the formula 2 being an ethylenediamine structure under the same addition amount, which may be because the -NH- in the amide group can also release active H ions to quench the free radicals generated in the aging process of the matrix.

[0100] The above examples of the application are only examples for clearly illustrating the application, and are not intended to limit the embodiments of the application. Other different forms of changes or variations can be made on the basis of the above description for those skilled in the art, and it is impossible to enumerate all the embodiments here. Any obvious changes or variations derived from the technical solutions of the application still fall within the protection scope of the application.

Claims

1. A three-arm branched hindered phenol compound represented by formula 5, In formula 5, R2is -(CH2) n or phenyl, wherein, n is an integer between 2 and 6.

2. The tri-armed branched hindered phenolic compound of claim 1, wherein The three-arm branched hindered phenol compound is one of the following:

3. The method for synthesizing the three-arm branched hindered phenolic compound of Formula 5 as described in claim 1, characterized in that... The method is: S1: dissolving a compound of formula 1 in methanol in a protective atmosphere A, adding a compound of formula 2, first-stage reaction at 0-5°C for 30-60 min, warming to 25-30°C for second-stage reaction for 12-24 h, separating and purifying the obtained reaction liquid to obtain a compound of formula 3; the molar ratio of the compound of formula 1 to the compound of formula 2 is 1:3.5-6; S2: dissolving the compound of formula 3 in step S1, a compound of formula 4 and a strong base in an organic solvent in a protective atmosphere B, stirring and reacting at 100-120°C for 6-12 h, post-treating the obtained reaction mixture to obtain the three-arm branched hindered phenol compound represented by formula 5; the molar ratio of the compound of formula 4 to the compound of formula 3 is 3-4:1; the molar ratio of the compound of formula 4 to the strong base is 1:1-5; In formulae 1, 2, 3, 5, R1is hydroxy or C1-C4alkoxy; R2is -(CH2) n or phenyl; R3is hydroxy or C1-C4alkoxy.

4. The method for synthesizing the three-arm branched hindered phenolic compound of formula 5 as described in claim 3, characterized in that: The volume of the methanol in step S1 is 5-10 L / mol based on the amount of substance of the compound of formula 1.

5. The method for synthesizing the three-arm branched hindered phenolic compound of Formula 5 as described in claim 3, characterized in that... The separation and purification in step S1 is: rotary evaporation of the reaction liquid, washing with a mixed solvent of methanol and toluene in a volume ratio of 1:10-15, drying to obtain the compound of formula 3.

6. The method for synthesizing the three-arm branched hindered phenolic compound of Formula 5 as described in claim 3, characterized in that: The protective atmosphere A in step S1 and the protective atmosphere B in step S2 are both nitrogen atmosphere.

7. The method for synthesizing the three-arm branched hindered phenolic compound of Formula 5 as described in claim 3, characterized in that: In step S2, the organic solvent is a mixed solvent of one or both of toluene and xylene; the volume of the organic solvent is 100-200 mL / g based on the mass of the compound of formula 3.

8. The method for synthesizing the three-arm branched hindered phenolic compound of Formula 5 as described in claim 3, characterized in that: The post-treatment in step S2 is: filtering the reaction mixture, drying the obtained filter cake to obtain the three-arm branched hindered phenol compound represented by formula 5.

9. The method for synthesizing the three-arm branched hindered phenolic compound of Formula 5 as described in claim 3, characterized in that: In step S2, the strong base is one or a mixture of two or more of sodium hydroxide, potassium hydroxide, lithium chloride and sodium methoxide.

10. Use of the three-arm branched hindered phenol compound of claim 1 in the preparation of a high-molecular antioxidant.

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