Oxidative coupling catalytic composition, polyphenylene ether and its preparation method and application

Abstract

The present application relates to the technical field of catalysts for oxidation coupling reaction, and particularly relates to an oxidation coupling catalytic composition, a polyphenyl ether and a preparation method and application thereof. The composition comprises an organic peroxide, a Schiff base and an amine-based compound; the molar ratio of the organic peroxide to the Schiff base is 1:(0.5-3); and the molar ratio of the Schiff base to the amine-based compound is 1:(0.5-2). In the oxidation coupling catalytic composition, the organic peroxide, the Schiff base and the amine-based compound interact with each other, so that a high yield can be achieved in a very short reaction time when the composition is used for oxidation coupling reaction, and the final product has a reduced glass transition temperature and improved processing performance while maintaining good thermal stability.

Description

Technical Field

[0001] This invention relates to the field of catalysts for oxidative coupling reactions, specifically to an oxidative coupling catalytic composition, polyphenylene ether, its preparation method, and its application. Background Technology

[0002] Polyphenylene oxide (PPE) is a high-strength engineering plastic developed in the 1960s and is one of the world's five major general-purpose engineering plastics. Based on its excellent dielectric properties, heat resistance, water absorption resistance, mechanical properties, and flame retardant properties, PPE has been widely used in electronics, machining, medical devices, and automotive parts. However, the high molecular weight of PPE synthesized by traditional solution methods has significant drawbacks, mainly manifested in high melt viscosity and poor flowability, which limits its application in copper-clad laminates (CCLs). To enable better application of PPE in the CCL field, its molecular weight must be reduced.

[0003] Low molecular weight polyphenylene oxide (PPO) retains the advantages of high molecular weight PPO while also addressing the challenges posed by high glass transition temperatures. Low molecular weight PPO can be obtained through direct synthesis or by redistribution of high molecular weight PPO. Currently, the most common method for synthesizing low molecular weight PPO is the redistribution of high molecular weight PPO.

[0004] For example, CN101389691A describes a redistribution reaction using polyphenylene ether (PPE), a raw material with a number-average molecular weight (NUMB) of over 10,000, polyphenolic compounds, and a free radical initiator, to produce low-molecular-weight PPE with a NUMB of less than 4,000. The redistribution method yields high-purity products, but the redistribution process is typically carried out at high temperatures, requiring significant energy. Furthermore, the resulting PPE has a wide molecular weight distribution and a high residual rate of high-molecular-weight PPE, leading to uneven distribution in subsequent applications on high-frequency, high-speed PCBs, thus affecting product performance. Low-molecular-weight PPE can also be synthesized directly. For instance, CN113698591A describes the preparation of low-molecular-weight PPE: 2,6-dimethylphenol undergoes an oxidative condensation polymerization reaction under oxygen-purified conditions and catalyzed by a copper-pyridine complex to obtain a PPE homopolymer. The reaction time is controlled to ensure that the NUMB of the resulting PPE homopolymer is 800-1500. Current direct synthesis methods for polyphenylene ethers involve the oxidation of 2,6-dimethylphenol with oxygen under the catalysis of copper-organic amine complexes. However, traditional methods result in high copper content and insufficient dielectric properties, and the use of oxygen as an oxidant poses certain safety risks. Therefore, it is essential to develop a more efficient and safer one-pot direct polymerization method for preparing low molecular weight polyphenylene ethers. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of excessive high molecular weight products and safety risks in the use of existing oxidative coupling catalytic systems, and to provide an oxidative coupling catalytic composition, polyphenylene ether, its preparation method and application.

[0006] The first aspect of the present invention provides an oxidation-coupled catalytic composition comprising an organic peroxide, a Schiff base, and an amine compound; wherein the molar ratio of the organic peroxide to the Schiff base is 1:(0.5-3); and the molar ratio of the Schiff base to the amine compound is 1:(0.5-2).

[0007] The second aspect of the present invention provides the use of the oxidative coupling catalytic composition described in the first aspect of the present invention in the oxidative coupling reaction of 2,6-dimethylphenol.

[0008] The third aspect of the present invention provides a method for preparing polyphenylene ether, the method comprising: oxidative polymerization of 2,6-dimethylphenol in the presence of an organic solvent in the presence of the oxidative coupling catalytic composition described in the first aspect of the present invention, followed by aging.

[0009] The fourth aspect of the present invention provides polyphenylene ether prepared by the preparation method of the third aspect of the present invention.

[0010] The fifth aspect of the present invention provides the application of the polyphenylene ether described in the fourth aspect of the present invention in copper clad laminates.

[0011] Compared with the prior art, the present invention has at least the following beneficial effects:

[0012] (1) The oxidative coupling catalytic composition of the present invention uses organic peroxides as oxidants, which can avoid the use of oxygen, and makes the reaction device simpler and safer when using the oxidative coupling catalytic composition of the present invention, with lower requirements for equipment.

[0013] (2) In the oxidative coupling catalytic composition of the present invention, the organic peroxide, Schiff base and amine compound interact with each other, which enables them to achieve a high yield in a very short reaction time when used in oxidative coupling reaction. The final product reduces the glass transition temperature while maintaining good thermal stability, thereby improving the processing performance.

[0014] (3) The oxidative coupling catalytic composition of the present invention can directly oxidatively couple the raw materials into the final polymerization product. For example, it can directly oxidatively couple 2,6-dimethylphenol to obtain a low molecular weight polyphenylene ether product, thus avoiding the generation of high molecular weight products in the system. Attached Figure Description

[0015] Figure 1 This is a differential scanning calorimetry (DSC) chromatogram of the polyphenylene ether product in Example 1. Detailed Implementation

[0016] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0017] The first aspect of the present invention provides an oxidation-coupled catalytic composition comprising an organic peroxide, a Schiff base, and an amine compound; wherein the molar ratio of the organic peroxide to the Schiff base is 1:(0.5-3); and the molar ratio of the Schiff base to the amine compound is 1:(0.5-2).

[0018] The oxidative coupling catalytic composition of this invention can avoid the use of oxygen. The interaction between the components in the oxidative coupling catalytic composition of this invention enables it to have a suitable polymerization rate during use, and can directly oxidatively couple polymer products. It can avoid the generation of high molecular weight polymers, so that the polymer products have good thermal stability and low glass transition temperature, thereby improving the processing performance.

[0019] According to the present invention, the molar ratio of organic peroxide to Schiff base can be 1:0.5, 1:0.9, 1:1.8, 1:2, 1:2.5, 1:3, or any two of the above ratios, preferably 1:(1-2.5). By employing the aforementioned embodiments, the components in the oxidative coupling catalytic composition can better synergize with each other, thereby improving the processing performance and dielectric properties of the polymer obtained when the oxidative coupling catalytic composition is used in oxidative coupling reactions.

[0020] According to the present invention, the molar ratio of Schiff base to amine compound can be 1:0.5, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, or any two of the above ratios, preferably 1:(1-1.5). By employing the foregoing embodiments, the components in the oxidative coupling catalytic composition can better synergize with each other, thereby improving the processing performance and dielectric properties of the polymer obtained when the oxidative coupling catalytic composition is used in oxidative coupling reactions.

[0021] In this invention, organic peroxides refer to organic compounds whose molecular structure contains a peroxy group (-OO-). According to a preferred embodiment of this invention, the organic peroxide is selected from at least one of 3,3,5,7,7-pentamethyl-1,2,4-trioxane, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane, dimethyl peroxide, tert-butyl hydroperoxide, cumene peroxide, triacetone peroxide, benzoyl peroxide, and methyl (trifluoromethyl)-1,3-diepoxypropane, preferably 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane and / or dimethyl peroxide, more preferably 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane.

[0022] According to a preferred embodiment of the present invention, the structure of the Schiff base is as shown in formula (I):

[0023]

[0024] In formula (Ⅰ), R', R”, and R”' are each independently selected from C1-C7 chain alkyl, C6-C12 aryl, and C4-C8 cyclic alkyl.

[0025] In this invention, C1-C7 chain alkyl refers to chain alkyl containing 1-7 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl. The chain alkyl can be straight-chain alkyl or branched-chain alkyl, and this invention does not have any special restrictions on this.

[0026] The C6-C12 aryl groups in this invention contain aryl groups with 6-12 carbon atoms, such as phenyl, methylphenyl, naphthyl, etc.

[0027] Examples of C4-C8 cyclic alkyl groups that can be listed in this invention include cyclobutyl, cyclopentyl, and cyclohexyl.

[0028] According to a preferred embodiment of the present invention, R' and R" are each independently selected from C1-C7 chain alkyl groups, preferably from C1-C3 chain alkyl groups. Methyl is used as an example to illustrate the advantages of the present invention, but the present invention is not limited thereto.

[0029] According to a preferred embodiment of the present invention, R”' is selected from C4-C8 cyclic alkyl groups, preferably C6 cyclic alkyl groups, i.e., cyclohexyl.

[0030] According to a preferred embodiment of the present invention, preferably, the Schiff base is selected from N-cyclohexylpropyl-2-imine Schiff bases.

[0031] According to the present invention, the selection of the amine compound is not particularly limited as long as the purpose of the present invention can be achieved. In a preferred embodiment, the amine compound is selected from aromatic amine compounds and / or aliphatic amine compounds.

[0032] In a preferred embodiment of the present invention, the amine compound is selected from diamine compounds and / or triamine compounds.

[0033] In this invention, fatty amines refer to organic amine compounds with carbon chain lengths within a certain range. In a preferred embodiment, the fatty amine compounds are selected from C1-C12 fatty amines, such as C1 fatty amines, C3 fatty amines, C5 fatty amines, C7 fatty amines, C9 fatty amines, C10 fatty amines, and C12 fatty amines, and are preferably selected from C4-C8 fatty amines.

[0034] In this invention, aromatic amines refer to amines containing aromatic substituents. In a preferred embodiment, the aromatic amine is selected from C6-C18 aromatic amines, such as C6, C7, C10, C12, C15, and C18 aromatic amines, and preferably from C8-C12 aromatic amines.

[0035] According to a particularly preferred embodiment of the present invention, the amine compound is selected from aliphatic amine compounds.

[0036] According to a particularly preferred embodiment of the present invention, the amine compound is selected from ternary amine compounds.

[0037] According to a particularly preferred embodiment of the present invention, the amine compound is selected from one or more of triethylamine, ethylenediamine, and p-aminodiphenylamine, more preferably triethylamine.

[0038] Traditional oxidative coupling catalysts often use materials containing metals such as copper as catalysts. These catalysts result in the presence of metals in the final polymer product, which can negatively impact the dielectric properties of the polymer. According to a preferred embodiment of the present invention, the composition is metal-free, preferably copper-free. The oxidative coupling catalytic composition of the present invention exhibits excellent oxidative coupling properties without the need for metals.

[0039] Each component in the oxidative coupling catalytic composition of the present invention can be stored independently or in combination as needed. Preferably, the organic peroxide is stored independently, and preferably the Schiff base and amine compound are stored independently or in combination.

[0040] The second aspect of the present invention provides the use of the oxidative coupling catalytic composition described in the first aspect of the present invention in the oxidative coupling reaction of 2,6-dimethylphenol.

[0041] In this invention, the oxidative coupling catalytic composition of this invention is used to catalyze the oxidation of 2,6-dimethylphenol to directly obtain low molecular weight polyphenylene ether products through oxidative coupling. Compared with the redistribution method, there is no residual high molecular weight PPO in the system, thus avoiding the problem of uneven distribution in subsequent applications.

[0042] The third aspect of the present invention provides a method for preparing polyphenylene ether. The method includes: oxidative polymerization of 2,6-dimethylphenol in the presence of an organic solvent in the presence of the oxidative coupling catalytic composition described in the first aspect of the present invention, followed by aging.

[0043] Using the oxidative coupling catalytic composition of this invention, 2,6-dimethylphenol can be catalytically oxidized directly to obtain low molecular weight polyphenylene ether products. Compared with the redistribution method, there is no residual high molecular weight PPO in the system, avoiding the problem of uneven distribution in subsequent applications.

[0044] According to the present invention, the reaction conditions for the oxidative polymerization are not particularly limited as long as the purpose of the present invention can be achieved. The oxidative polymerization is carried out under certain temperature and dynamic mixing conditions. Preferably, the conditions for the oxidative polymerization include: a temperature of 20-50°C; a stirring speed of 400-2000 r / min; and a time of 1-6 h.

[0045] According to a preferred embodiment of the present invention, the oxidative polymerization includes a first oxidative polymerization followed by a second oxidative polymerization; the temperature of the first oxidative polymerization is lower than the temperature of the second oxidative polymerization.

[0046] According to a preferred embodiment of the present invention, the temperature difference between the first oxidative polymerization and the second oxidative polymerization is 10-30°C, for example, 10°C, 15°C, 20°C, 25°C, or 30°C.

[0047] According to a preferred embodiment of the present invention, the temperature of the first oxidative polymerization is 20-30°C.

[0048] According to a preferred embodiment of the present invention, the temperature of the second oxidative polymerization is 40-50°C.

[0049] According to the present invention, oxidative polymerization is generally carried out under dynamic conditions. In a preferred embodiment, the stirring speed of the first oxidative polymerization is lower than that of the second oxidative polymerization. Preferably, the difference between the stirring speeds of the first and second oxidative polymerizations is 400-1600 r / min, for example, 400 r / min, 600 r / min, 800 r / min, 1000 r / min, 1200 r / min, 1400 r / min, or 1600 r / min.

[0050] According to a preferred embodiment of the present invention, the stirring speed of the first oxidative polymerization is 400-600 r / min.

[0051] According to a preferred embodiment of the present invention, the stirring speed of the second oxidative polymerization is 1000-2000 r / min.

[0052] In this invention, the polymerization reaction time can be selected according to temperature, dynamic conditions, etc., preferably the first oxidative polymerization time is 1-2 hours, and preferably the second oxidative polymerization time is 1-4 hours.

[0053] According to a preferred embodiment of the present invention, the curing conditions include: being carried out in the presence of an inert gas, wherein the inert gas can be of a type conventional in the art, such as nitrogen or argon, and the inert gas is continuously introduced into the reaction system so that the curing is carried out in the presence of the inert gas, for example, the flow rate of the inert gas is 10-20 ml / min.

[0054] According to a preferred embodiment of the present invention, the aging conditions include an aging temperature of 60-80°C.

[0055] According to the present invention, there is no particular limitation on the curing time, which is related to the curing temperature to a certain extent. Preferably, the curing conditions include a curing time of 1-2 hours.

[0056] According to the present invention, it is understood that the reaction product obtained after aging contains polyphenylene ether, organic solvents and other possible impurities. Preferably, the preparation method of the present invention further includes a separation and purification step after aging. The separation and purification method is not particularly limited. In one embodiment, the separation and purification step includes: sequentially performing solid-liquid separation, solid phase fractionation washing and drying.

[0057] According to the present invention, the solid-liquid separation in the separation and purification step can be performed using methods conventional in the art, such as centrifugation.

[0058] According to the present invention, in order to reduce the amount of solvent used and to perform washing and purification more efficiently, the solid-phase fractional washing preferably includes a first-stage solvent wash, a second-stage alkaline wash, and a third-stage water wash. The solvent in the first-stage solvent wash includes, but is not limited to, at least one selected from acetonitrile, methanol, ethanol, diethyl ether, acetone, and toluene.

[0059] According to the present invention, in order to remove the byproduct biphenylquinone, an alkaline washing is performed using an alkaline aqueous solution. Preferably, the pH value of the alkaline aqueous solution used for alkaline washing is 11-13. The alkaline aqueous solution can be a conventional alkaline aqueous solution in the art, such as an aqueous solution of sodium hydroxide.

[0060] According to the present invention, as long as the purpose of the present invention can be achieved, the amount of organic peroxide in the oxidative coupling catalytic composition is not particularly limited. Preferably, the molar ratio of 2,6-dimethylphenol to organic peroxide in the oxidative coupling catalytic composition is 1:(0.5-3.0), and more preferably 1:(1.5-2.5).

[0061] According to the present invention, the main function of the organic solvent is to enable the raw material 2,6-dimethylphenol to uniformly contact the oxidative coupling catalytic composition and increase the occurrence of the oxidative polymerization reaction. The amount and type of the organic solvent are sufficient to form a homogeneous system. Preferably, the total mass of 2,6-dimethylphenol and the organic solvent is used as a basis, and the mass content of 2,6-dimethylphenol is 1-5%. Preferably, the organic solvent is selected from at least one of methanol, ethanol, isopropanol, ethyl acetate, butyl butyrate, N-methylpyrrolidone, sulfolane, 1,4-dioxane, acetone, acetonitrile, cyclohexane, tetrahydrofuran, benzyl alcohol, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0062] In this invention, there are no special restrictions on the order of addition of each material during the oxidative polymerization reaction of 2,6-dimethylphenol, which will not be described in detail here.

[0063] The fourth aspect of the present invention provides polyphenylene ether prepared by the preparation method of the third aspect of the present invention.

[0064] The polyphenylene ether prepared by the present invention has a high thermal decomposition temperature, preferably 410-440℃, and more preferably 420-430℃.

[0065] The polyphenylene ether prepared by the present invention has a low glass transition temperature, preferably 160-200℃, and more preferably 170-180℃.

[0066] The polyphenylene ether prepared by the present invention has a suitable number-average molecular weight, preferably 2000-5000, more preferably 2500-4000, and even more preferably 2500-3500.

[0067] The polyphenylene ether prepared in this invention has a narrow molecular weight distribution, preferably with a molecular weight distribution index of 1.3-2.0, and more preferably 1.4-1.8.

[0068] The polyphenylene ether prepared in this invention is free of copper, and preferably the copper content in the polyphenylene ether is 0 ppm.

[0069] The dielectric properties of the polyphenylene ether prepared in this invention are preferably as follows: the dielectric constant is 1.6-2.2, 1.8-2.0; and the dielectric loss is 1.4 × 10⁻⁶. -3 -2.5×10 -3 Preferably 1.5×10 -3 -2.0×10 -3 More preferably 1.5×10 -3 -1.8×10 -3 .

[0070] The fifth aspect of the present invention provides the application of the polyphenylene ether described in the fourth aspect of the present invention in copper clad laminates.

[0071] The polyphenylene ether in this invention has good applications in copper clad laminates, especially in high-frequency and high-speed PCBs, where it has advantages in uniform distribution and dielectric properties.

[0072] The present invention will be described in detail below through embodiments. In the following embodiments and comparative examples:

[0073] The thermal decomposition temperature of polyphenylene ether was obtained by thermogravimetric analysis.

[0074] The glass transition temperature of polyphenylene oxide was determined and analyzed by differential scanning calorimetry.

[0075] The number-average molecular weight of polyphenylene ether was determined by gel permeation chromatography.

[0076] The molecular weight distribution index of polyphenylene ether was determined and analyzed by gel permeation chromatography.

[0077] The dielectric properties of polyphenylene ether were determined and analyzed by dielectric spectrometry.

[0078] Example 1

[0079] Preparation of polyphenylene ether:

[0080] (1) Weigh 91.65 mg of 2,6-dimethylphenol and dissolve it in 10 mL of acetonitrile. Then add 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane, N-cyclohexylpropyl-2-imine (CAS No.: 6407-36-9) Schiff base and triethylamine to the reactor. The molar ratio of N-cyclohexylpropyl-2-imine Schiff base to triethylamine is 1:1.1, the molar ratio of 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane to Schiff base is 1:1.5, and the molar ratio of 2,6-dimethylphenol to organic peroxide is 1:1.5. Set the pre-reaction stirring speed to 400 r / min and polymerize at 20 °C for 1 h. Then set the stirring speed to 1000 r / min and the reaction temperature to 40 °C and polymerize for 1 h to obtain a mixture.

[0081] (2) Maturation: Nitrogen gas is introduced into the reacted mixture at a flow rate of 10 ml / min, and the temperature is raised to 60°C for 1 hour.

[0082] (3) Separation and purification: After the aging process, the reactants were centrifuged to obtain a precipitate. Acetonitrile was used for primary solvent washing, followed by secondary washing with sodium hydroxide aqueous solution at pH 11, and then tertiary water washing. The washed product was placed in a vacuum oven and dried at 80°C for 12 hours to obtain a white polyphenylene ether product.

[0083] Differential scanning calorimetry analysis of polyphenylene ether products, such as Figure 1 As shown, polyphenylene ether synthesized by traditional methods generally has a glass transition temperature greater than 210℃ and poor processability. Figure 1 It can be seen that the glass transition temperature of this polyphenylene ether product is significantly lower than that of polyphenylene ether synthesized by the traditional method, and the processing performance is improved.

[0084] Example 2

[0085] Preparation of polyphenylene ether:

[0086] (1) Weigh 91.65 mg of 2,6-dimethylphenol and dissolve it in 10 mL of acetonitrile. Then add 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane, N-cyclohexylpropyl-2-imine Schiff base and triethylamine to the reactor. The molar ratio of N-cyclohexylpropyl-2-imine Schiff base to triethylamine is 1:1.3, the molar ratio of 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane to Schiff base is 1:2.5, and the molar ratio of 2,6-dimethylphenol to organic peroxide is 1:2.5. Set the pre-reaction stirring speed to 600 r / min and keep the pre-reaction temperature at 30 °C for 2 h. Then set the stirring speed to 2000 r / min and the reaction temperature to 50 °C and carry out the polymerization reaction for 4 h to obtain the mixture.

[0087] (2) Maturation: Nitrogen gas is introduced into the reacted mixture at a flow rate of 20 ml / min, and the temperature is raised to 80℃ for 2 hours.

[0088] (3) Separation and purification: After the aging process, the reactants were centrifuged to obtain a precipitate. Acetonitrile was used for primary solvent washing, followed by secondary washing with sodium hydroxide aqueous solution at pH 12, and then tertiary water washing. The washed product was placed in a vacuum oven and dried at 80°C for 12 hours to obtain a white polyphenylene ether product.

[0089] Example 3

[0090] Preparation of polyphenylene ether:

[0091] (1) Weigh 91.65 mg of 2,6-dimethylphenol and dissolve it in 10 mL of acetonitrile. Then add 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane, N-cyclohexylpropyl-2-imine Schiff base, and triethylamine to the reactor. The molar ratio of N-cyclohexylpropyl-2-imine Schiff base to triethylamine is 1:1, the molar ratio of 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane to Schiff base is 1:1.5, and the molar ratio of 2,6-dimethylphenol to organic peroxide is 1:2. Set the pre-reaction stirring speed to 500 r / min and prepolymerize at 25 °C for 1.5 h. Then set the stirring speed to 1500 r / min and the reaction temperature to 45 °C and carry out the polymerization reaction for 3 h to obtain a mixture.

[0092] (2) Maturation: Nitrogen gas is introduced into the reacted mixture at a flow rate of 12 ml / min, and the temperature is raised to 70°C for 1.5 h.

[0093] (3) Separation and purification: After the aging process, the reactants were centrifuged to obtain a precipitate. Acetonitrile was used for primary solvent washing, followed by secondary washing with sodium hydroxide aqueous solution at pH 11.5, and then tertiary water washing. The product after tertiary water washing was placed in a vacuum oven and dried at 80°C for 12 hours to obtain a white polyphenylene ether product.

[0094] Example 4

[0095] The method is the same as in Example 1, except that:

[0096] The molar ratio of N-cyclohexylpropyl-2-imine Schiff base to triethylamine is 1:0.5.

[0097] Example 5

[0098] The method is the same as in Example 1, except that:

[0099] The molar ratio of N-cyclohexylpropyl-2-imine Schiff base to triethylamine is 1:2.

[0100] Example 6

[0101] The method is the same as in Example 1, except that:

[0102] Replace 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane with an equimolar amount of 3,3,5,7,7-pentamethyl-1,2,4-trioxacycloheptane.

[0103] Example 7

[0104] The method is the same as in Example 1, except that:

[0105] Replace triethylamine with an equimolar amount of ethylenediamine.

[0106] Example 8

[0107] The method is the same as in Example 1, except that:

[0108] Replace triethylamine with an equimolar amount of p-aminodiphenylamine.

[0109] Example 9

[0110] The method is the same as in Example 1, except that:

[0111] Without a ripening step, the oxidatively polymerized mixture was directly separated and purified according to the separation and purification method in Example 1 to obtain polyphenylene ether.

[0112] Comparative Example 1

[0113] The method is the same as in Example 1, except that:

[0114] Replace 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane with ammonium persulfate.

[0115] Comparative Example 2

[0116] The method is the same as in Example 1, except that the molar ratio of N-cyclohexylpropyl-2-imine Schiff base to triethylamine is 1:4, and the molar ratio of 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane to Schiff base is 1:0.1.

[0117] Comparative Example 3

[0118] The method is the same as in Example 1, except that the molar ratio of N-cyclohexylpropyl-2-imine Schiff base to triethylamine is 1:0.1, and the molar ratio of 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane to Schiff base is 1:5.

[0119] The test results of polyphenylene ether in the examples and comparative examples are shown in Table 1:

[0120] Table 1

[0121]

[0122]

[0123] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An oxidation-coupled catalytic composition, characterized in that, The composition comprises an organic peroxide, a Schiff base, and an amino compound; the molar ratio of the organic peroxide to the Schiff base is 1:(0.5-3); and the molar ratio of the Schiff base to the amino compound is 1:(0.5-2).

2. The composition according to claim 1, wherein, The molar ratio of the organic peroxide to the Schiff base is 1:(1-2.5); and / or The molar ratio of the Schiff base to the amine compound is 1:(1-1.5); and / or The organic peroxide is selected from at least one of 3,3,5,7,7-pentamethyl-1,2,4-trioxane, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane, dimethyl peroxide, tert-butyl hydroperoxide, cumene peroxide, triacetone peroxide, benzoyl peroxide, and methyl (trifluoromethyl)-1,3-diepoxypropane, preferably 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane and / or dimethyl peroxide; and / or The structure of the Schiff base is shown in formula (Ⅰ): In formula (Ⅰ), R', R”, and R”' are each independently selected from C1-C7 chain alkyl, C6-C12 aryl, and C4-C8 cyclic alkyl; Preferably, R' and R'" are each independently selected from C1-C7 chain alkyl groups, preferably from C1-C3 chain alkyl groups; and / or R”' is selected from C4-C8 cyclic alkyl groups, preferably C6 cyclic alkyl groups; Preferably, the Schiff base is selected from N-cyclohexylpropyl-2-imine Schiff bases.

3. The composition according to claim 1 or 2, wherein, The amine compounds are selected from aromatic amine compounds and / or aliphatic amine compounds; The amine compounds are selected from diamine compounds and / or triamine compounds; Preferably, the fatty amine compound is selected from C1-C12 fatty amines, more preferably from C4-C8 fatty amines; and / or The aromatic amine is selected from C6-C18 aromatic amines, preferably from C8-C12 aromatic amines; More preferably, the amine compound is selected from aliphatic amine compounds and / or triamine compounds, preferably one or more of triethylamine, ethylenediamine, and p-aminodiphenylamine, more preferably triethylamine; and / or The composition is free of metals, preferably free of copper; and / or The organic peroxides are stored independently; and / or The Schiff bases and amine compounds may be stored independently or in combination.

4. The use of the oxidative coupling catalytic composition according to any one of claims 1-3 in the oxidative coupling reaction of 2,6-dimethylphenol.

5. A method for preparing polyphenylene ether, characterized in that, The preparation method includes: In the presence of the oxidative coupling catalytic composition according to any one of claims 1-3, 2,6-dimethylphenol undergoes oxidative polymerization in the presence of an organic solvent, followed by aging.

6. The preparation method according to claim 5, wherein, The conditions for the oxidative polymerization reaction include: Temperature is 20-50℃; and / or The stirring speed is 400-2000 r / min; and / or The time is 1-6 hours; and / or The conditions for ripening include: Performed in the presence of an inert gas; and / or The aging temperature is 60-80℃; and / or The curing time is 1-2 hours; and / or The preparation method also includes a separation and purification step after aging; Preferably, the separation and purification steps include: sequentially performing solid-liquid separation, solid phase fractionation washing, and drying; More preferably, the solid-phase fractional washing includes a first-stage solvent washing, a second-stage alkaline washing, and a third-stage water washing. The solvent in the first-stage solvent washing includes at least one of acetonitrile, methanol, ethanol, diethyl ether, acetone, and toluene. Preferably, the pH value of the alkaline aqueous solution used in the alkaline washing is 10-13.

7. The preparation method according to claim 5 or 6, wherein, The oxidative polymerization includes a first oxidative polymerization followed by a second oxidative polymerization; the temperature of the first oxidative polymerization is lower than the temperature of the second oxidative polymerization, preferably the temperature difference between the first oxidative polymerization and the second oxidative polymerization is 10-30℃; Preferably, the stirring speed of the first oxidative polymerization is lower than that of the second oxidative polymerization, and more preferably the difference between the stirring speeds of the first oxidative polymerization and the second oxidative polymerization is 400-1600 r / min; and / or The temperature of the first oxidative polymerization is 20-30℃; and / or The temperature of the second oxidative polymerization is 40-50℃; and / or The stirring speed for the first oxidative polymerization is 400-600 r / min; and / or The stirring speed for the second oxidative polymerization is 1000-2000 r / min; and / or The first oxidative polymerization takes 1-2 hours; and / or The second oxidative polymerization takes 1-4 hours.

8. The preparation method according to any one of claims 5-7, wherein, The molar ratio of the organic peroxide in the 2,6-dimethylphenol-oxidative coupling catalytic composition is 1:(0.5-3.0), preferably 1:(1.5-2.5); and / or Based on the total mass of 2,6-dimethylphenol and organic solvent, the mass content of 2,6-dimethylphenol is 1-5%; and / or The organic solvent is selected from at least one of methanol, ethanol, isopropanol, ethyl acetate, butyl butyrate, N-methylpyrrolidone, sulfolane, 1,4-dioxane, acetone, acetonitrile, cyclohexane, tetrahydrofuran, benzyl alcohol, N,N-dimethylformamide, and N,N-dimethylacetamide.

9. A polyphenylene ether prepared by the preparation method according to any one of claims 5-8; Preferably, The thermal decomposition temperature of the polyphenylene ether is 410-440℃, preferably 420-430℃; and / or The glass transition temperature of the polyphenylene ether is 160-200℃, preferably 170-180℃; and / or The polyphenylene ether has a number average molecular weight of 2000-5000, preferably 2500-3500; and / or The polyphenylene ether has a molecular weight distribution index of 1.3-2.0, preferably 1.4-1.8; and / or The copper content in the polyphenylene ether is 0 ppm; and / or; The dielectric constant of the polyphenylene ether is 1.6-2.2, preferably 1.8-2.0; the dielectric loss is 1.4 × 10⁻⁶. -3 -2.5×10 -3 Preferably 1.5×10 -3 -1.8×10 -3 .

10. The use of the polyphenylene ether of claim 9 in copper clad laminates.

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