Catalyst for cyclohexanetetracarboxylic acid synthesis and preparation method thereof, and synthesis method of cyclohexanetetracarboxylic acid

Abstract

The application provides a catalyst for cyclohexane tetracarboxylic acid synthesis, a preparation method of the catalyst and a synthesis method of cyclohexane tetracarboxylic acid, and belongs to the field of catalysts.The catalyst comprises a carrier, noble metal and an additive;the noble metal is at least one selected from Pd, Au, Pt, Rh and Ru; and the additive is polyphenyl ether.The application solves the problems of high cost and quick loss of active components of the catalyst in the prior art, and can be applied to industrial production of cyclohexane tetracarboxylic acid.

Description

Technical Field

[0001] This invention relates to the field of catalysts, and in particular to catalysts for the synthesis of cyclohexanetetracarboxylic acid, methods for preparing the catalyst, and methods for synthesizing cyclohexanetetracarboxylic acid. Background Technology

[0002] Polyimide (PI) is a class of polymers containing imide rings (-CO-N-CO-) in its main chain. It is obtained by the condensation polymerization of diacids and diamines, and is an aromatic heterocyclic polymer containing imide groups in its molecular backbone. Due to its excellent temperature resistance, superior mechanical properties, excellent dielectric and electrical properties, chemical stability, and non-toxicity and environmental friendliness, it is widely used in high-tech fields such as aerospace, microelectronics, nanotechnology, liquid crystals, separation membranes, and lasers, and is gradually penetrating the civilian market, earning it the reputation of a "problem solver."

[0003] With the increasing multifunctionality of PI resin films, especially for properties requiring high transparency, the polymer monomer of PI has been changed from pyromellitic dianhydride (PMDA) to its hydrogenated compound 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA), which is then further reacted with ODA to obtain HPMDA-based PI. Because it contains no aromatic components, the resulting PI exhibits excellent transparency, low dielectric constant and dielectric loss, high breakdown strength, low moisture absorption, and good adhesion to substrates such as metals. Based on the unique physicochemical properties of HPMDA-based PI, it has broad application prospects in high-tech fields such as integrated circuits and liquid crystal displays.

[0004] Therefore, many companies both domestically and internationally are actively developing HPMDA-based PI films. Among them, Japanese companies such as Mitsubishi Gas Chemical, Nippon Steel Chemical, and Rika Nippon Chemical have long been committed to HPMDA development and have successively achieved success. Domestic research on HPMDA started later. According to public reports, companies such as the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences, Sunshine Pharmaceutical, Qikai Pharmaceutical Technology, and Kesheng Chemical are engaged in HPMDA research and development, but there are currently no reports of industrialization.

[0005] The synthesis process of HPMDA is divided into one-step and two-step methods. The one-step method, represented by Mitsubishi Gas Industries and New Nippon Rikka, uses pyromellitic dianhydride (PMA) as the starting material, and prepares HPMDA through hydrogenation and dehydration cyclization. Currently industrialized technologies all use Rh or Ru-Pd composite supported catalysts as hydrogenation catalysts (Methods for preparing hydrogenated aromatic polycarboxylic acids and methods for preparing hydrogenated aromatic polycarboxylic anhydrides. CN 100424062). There are also patent reports on research using Ru, Pd, and other noble metals and their mixed / composite (alloy) catalysts (Methods for manufacturing alicyclic carboxylic acids and catalysts used in this method. CN 103502197B). The two-step method, represented by Nippon Steel Corporation, uses pyromellitic dianhydride as the starting material, and prepares cyclohexanetetracarboxylic acid through esterification, hydrogenation, and hydrolysis, finally cyclizing and dehydrating to obtain HPMDA. A Ru-based supported catalyst is used as the hydrogenation catalyst. Domestic research institutions and companies, represented by the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences, mainly use a two-step process for related technology development (a method for manufacturing alicyclic carboxylic acid esters. CN 106866415A). Only a few companies, such as Sunshine Pharmaceutical, use a one-step process for research and development (a method for preparing electronic-grade hydrogenated pyromellitic dianhydride. CN103992330B). Currently, the relatively mature process for HPMDA uses an Rh-based catalyst for hydrogenation to synthesize HPMA, followed by a dehydration cyclization reaction to obtain HPMDA. However, this hydrogenation catalyst has disadvantages such as high cost and rapid loss of active components. Summary of the Invention

[0006] One of the technical problems to be solved by the present invention is that the catalysts in the prior art are expensive and the active components are lost quickly. The present invention provides a new catalyst for the synthesis of cyclohexanetetracarboxylic acid, which has the characteristics of low cost and slow loss of active components.

[0007] The second technical problem to be solved by the present invention is to provide a method for preparing a catalyst corresponding to one of the above-mentioned technical problems.

[0008] The third technical problem to be solved by the present invention is to provide a method for synthesizing cyclohexanetetracarboxylic acid using the catalyst described in one of the above-mentioned technical problems.

[0009] According to one aspect of the present invention, a catalyst for the synthesis of cyclohexanetetracarboxylic acid is provided, the catalyst comprising a support, a noble metal, and an auxiliary agent; the noble metal is selected from at least one of Pd, Au, Pt, Rh, and Ru; the auxiliary agent is poly2,6-dimethyl-1,4-phenylene ether (hereinafter referred to as polyphenylene ether).

[0010] In this invention, the noble metal exists in the catalyst in the form of an elemental metal.

[0011] Optionally, the content of the precious metal in the catalyst is 2.0 to 20.0 g / L, and the content of the polyphenylene ether in the catalyst is 0.1 to 3.0 g / L.

[0012] In the above technical solution, as a non-limiting example, the content of precious metals in the catalyst is 3.0 g / L, 4.0 g / L, 5.0 g / L, 6.0 g / L, 7.0 g / L, 8.0 g / L, 9.0 g / L, 10.0 g / L, 11.0 g / L, 12.0 g / L, 13.0 g / L, 14.0 g / L, 15.0 g / L, 16.0 g / L, 17.0 g / L, 18.0 g / L, 19.0 g / L, or any value between any two of the above points.

[0013] In the above technical solution, as a non-limiting example, the content of polyphenylene ether in the catalyst is 0.2 g / L, 0.5 g / L, 1.0 g / L, 1.5 g / L, 2.0 g / L, 2.5 g / L, 3.0 g / L, or any value between any two of the above points.

[0014] Optionally, the bulk density of the catalyst is 400–600 g / L.

[0015] Optionally, the number-average molecular weight M of the polyphenylene ether is... n The range is 10,000 to 30,000.

[0016] Optionally, the precious metal is a mixture of Pd and Au.

[0017] Optionally, the mass ratio of Pd to Au in the mixture is 1:(0.1 to 1).

[0018] Optionally, the mass ratio of Pd to Au in the mixture is 1:(0.1 to 0.5).

[0019] Optionally, the support is selected from at least one of activated carbon, SiO2, Al2O3, and TiO2.

[0020] Optionally, the activated carbon is coconut shell carbon, such as flake coconut shell carbon, preferably with a particle size of 10-30 mesh.

[0021] Optionally, the specific surface area of ​​the carrier is 1000–2000 m². 2 / g, with a total adsorption pore volume of 0.5–1.0 cm³. 3 / g.

[0022] In the above technical solution, as a non-limiting example, the specific surface area of ​​the carrier is 1050 m². 2 / g、1100m 2 / g、1150m 2 / g、1200m 2 / g、1250m 2 / g、1300m 2 / g, 1350m 2 / g, 1400m 2 / g, 1450m 2 / g, 1500m 2 / g, 1550m 2 / g, 1600m 2 / g、1650m 2 / g、1700m 2 / g、1750m 2 / g、1800m 2 / g, 1850m 2 / g、1900m 2 / g、1950m 2 / g, or any value between any two of the above points.

[0023] In the above technical solution, as a non-limiting example, the total adsorption pore volume of the carrier is 0.55 cm³. 3 / g, 0.60cm 3 / g, 0.65cm 3 / g, 0.70cm 3 / g, 0.75cm 3 / g, 0.80cm 3 / g, 0.85cm 3 / g, 0.90cm 3 / g, 0.95cm 3 / g, or any value between any two of the above points.

[0024] According to another aspect of the present invention, a method for preparing the above-mentioned catalyst is provided, comprising:

[0025] (1) Mix solution I containing noble metal salt with the support and dry to obtain catalyst precursor A;

[0026] (2) Reduce catalyst precursor A to obtain catalyst precursor B;

[0027] (3) The catalyst precursor B is mixed with solution II containing polyphenylene ether and dried to obtain the catalyst.

[0028] Optionally, the solvent for solution I can be water; the solvent for solution II can be a solvent capable of dissolving polyphenylene ether, preferably chloroform.

[0029] Optionally, in step (1), the precious metal salt is selected from at least one of the hydrochloride, nitrate or acetate of a precious metal.

[0030] Optionally, in step (1), the concentration of the noble metal in the solution I containing the noble metal salt is 2.0 to 20.0 g / L.

[0031] Optionally, in step (1), the solid-liquid ratio of the carrier to solution I containing the noble metal salt is 1 g: (1-10) mL.

[0032] Optionally, in step (2), the reduction is a solution reduction method or a gas reduction method.

[0033] Optionally, the reducing agent in the solution reduction method is selected from hydrazine hydrate or sodium formate. When using hydrazine hydrate for solution reduction, the concentration of the hydrazine hydrate solution can be 10% to 20%.

[0034] Optionally, in step (3), the concentration of polyphenylene ether in the solution II containing polyphenylene ether is 0.1 to 10.0 g / L.

[0035] Optionally, in step (3), the solid-liquid ratio of the catalyst precursor B to the solution II containing polyphenylene ether is 1 g: (1-5) mL.

[0036] In the above technical solution, as a non-limiting example, the concentration of the precious metal in the solution I containing the precious metal salt in step (1) is 4.0 g / L, 6.0 g / L, 8.0 g / L, 10.0 g / L, 12.0 g / L, 14.0 g / L, 16.0 g / L, 18.0 g / L, or any value between any two of the above points.

[0037] In the above technical solution, as a non-limiting example, the concentration of polyphenylene ether in the solution II containing polyphenylene ether in step (3) is 0.2 g / L, 0.5 g / L, 1.0 g / L, 1.5 g / L, 2.0 g / L, 2.5 g / L, 3.0 g / L, 3.5 g / L, 4.0 g / L, 4.5 g / L, 5.0 g / L, 5.5 g / L, 6.0 g / L, 6.5 g / L, 7.0 g / L, 7.5 g / L, 8.0 g / L, 8.5 g / L, 9.0 g / L, 9.5 g / L, or any value between any two of the above points.

[0038] According to another aspect of the present invention, a method for synthesizing cyclohexanetetracarboxylic acid is provided, comprising a raw material containing pyromellitic acid and H2, wherein cyclohexanetetracarboxylic acid is obtained by reaction in the presence of a catalyst;

[0039] The catalyst includes at least one selected from the catalysts described above and the catalysts obtained by the preparation methods described above.

[0040] Optionally, the reaction temperature is 50–150°C.

[0041] Optionally, the reaction time is 1.0 to 100.0 h.

[0042] Optionally, the partial pressure of H2 in the reaction is 5.0–10.0 MPa.

[0043] In the above technical solutions, as a non-limiting example, the reaction temperature is 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, or any value between any two of the above points.

[0044] In the above technical solutions, as a non-limiting example, the reaction time is 5h, 10h, 12h, 24h, 36h, 48h, 60h, 72h, 84h, 96h, or any value between any two of the above points.

[0045] In the above technical solutions, as a non-limiting example, the partial pressure of H2 in the reaction is 5.5MPa, 6.0MPa, 6.5MPa, 7.0MPa, 7.5MPa, 8.0MPa, 8.5MPa, 9.0MPa, 9.5MPa, or any value between any two of the above points.

[0046] In the above technical solution, the reaction solvent is not particularly limited as long as it can dissolve pyromellitic acid. The reaction solvent can be selected from, but is not limited to, alcohols such as water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol; ethers such as diethyl ether, diisobutyl ether, n-butyl ether, and THF; esters such as methyl acetate and ethyl acetate; and ketones such as acetone and methyl ethyl ketone. Preferably, water, methanol, ethanol, 1-propanol, and 2-propanol are used, with water being more preferred.

[0047] The key technology of this invention is the catalyst. As for the specific process conditions used in the synthesis method, those skilled in the art can make reasonable choices and achieve comparable technical effects.

[0048] The present invention has the following beneficial effects:

[0049] The catalyst of this invention uses noble metals such as Pd and Au as active components and adds polyphenylene ether as an auxiliary agent, which significantly reduces the loss rate of active components. However, this invention found that when the polyphenylene ether content is too high, it will cause a decrease in catalyst activity. Therefore, it was determined that when the polyphenylene ether content is 0.1-3.0 g / L, the resulting catalyst has good catalytic activity in the synthesis of cyclohexanetetracarboxylic acid. Detailed Implementation

[0050] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0051] All reaction pressures described in this invention are gauge pressures.

[0052] The conversion rate of pyromellitic acid in this invention is calculated using the following formula:

[0053] Pyromellitic acid conversion rate (α) = (m (PMA,in) -m (PMA,out) ) / m (PMA,in) ×100%

[0054] cyclohexanetetracarboxylic acid selectivity (S) = m (HPMA) / M (HPMA) / ((m (PMA,in) -m (PMA,out) ) / M (PMA) ) ×100%

[0055] Cyclohexanetetracarboxylic acid yield = α × S × 100%

[0056] PMA: Pyromellitic acid;

[0057] HPMA: Cyclohexanetetracarboxylic acid;

[0058] m (PMA,in) : The mass of PMA added before the reaction;

[0059] m (PMA,out) : Remaining mass of PMA after the reaction;

[0060] m (HPMA) : Mass of HPMA produced in the reaction;

[0061] M (HPMA) : Molecular weight of HPMA;

[0062] M (PMA) : Molecular weight of PMA.

[0063] In this invention, the calculation of the loss rate of active components = (precious metal content before reaction) - (precious metal content after reaction) / (precious metal content before reaction) × 100%.

[0064] Example 1

[0065] (I) Catalyst Preparation

[0066] (1) Select appropriate amounts of palladium chloride (H₂PdCl₄), chloroauric acid (HAuCl₄), and pure water to prepare 250.0 ml of an aqueous solution containing 2.5 g of precious metals Pd and Au, as impregnation solution A, where the mass ratio of Pd to Au is 1:0.1. Impregnation solution A is mixed with 100.0 g of activated carbon (sheet coconut shell carbon, size: 20±2 mesh, specific surface area: 1500±50 μm). 2 / g, pore volume: 0.6±0.03cm 3 The mixture of / g) was impregnated at 70°C for 1 h on a rotary evaporator. After the solvent was evaporated under reduced pressure, the wet catalyst precursor was placed in a forced-air drying oven and dried at 110°C for 6 h to obtain catalyst precursor a.

[0067] (2) Mix 100.0g of catalyst precursor a with 200mL of 15% hydrazine hydrate (N2H4·H2O) solution (solid-liquid ratio of 1g:2mL), let stand for 3h, filter and wash with water until pH value is neutral, and dry at 120℃ for 3h to obtain reduced catalyst precursor b.

[0068] (3) Polyphenylene ether (C8H8O) is selected. n (Number average molecular weight Mn: 20000), prepare 250.0 ml of chloroform solution containing 0.5 g polyphenylene ether as impregnation solution B, wherein the concentration of polyphenylene ether is 2.0 g / L, mix with 125.0 g of reduced catalyst precursor b, let stand at room temperature for 6 h, place the wet catalyst in a forced-air drying oven, and dry at 60 °C for 24 h to obtain catalyst product c;

[0069] (II) Catalyst Performance Evaluation

[0070] The catalyst was evaluated using a 1L high-pressure autoclave reactor. The specific reaction and post-treatment steps were as follows:

[0071] a) Add 60.0g of pyromellitic acid (C) to a 1000ml autoclave. 10 H6O8 (purity: >98.0%), along with 340g of deionized water and 6.0g of catalyst product c, were added. Hydrogen gas was introduced into the high-pressure reactor and the hydrogen partial pressure was controlled at 7.0MPa. The temperature was controlled at 90℃, and the reaction was carried out for 24h.

[0072] b) Then cool to room temperature (20±5℃), discharge and filter. The catalyst is separated from the filter cake. The used catalyst is used to analyze the content of active components and calculate the loss rate of active components. After the filtrate is dehydrated by vacuum distillation, cyclohexanetetracarboxylic acid (HPMA) is precipitated. HPLC is used for quantitative analysis. The reaction conversion rate, selectivity, yield and purity are calculated based on the analysis results.

[0073] (III) Characterization of catalyst and support

[0074] a) The active components (Pd, Au) of the catalyst before and after evaluation were quantitatively analyzed using a Thermo iCAP 6300 inductively coupled plasma atomic emission spectrometer (ICP-AES), and the loss rate of the active components was calculated.

[0075] b) The total specific surface area and total adsorption pore volume of the carrier activated carbon were determined using a Micromeritics ASAP 2460 surface area and porosity analyzer.

[0076] For ease of comparison, the catalyst preparation conditions and catalyst composition are listed in Table 1, the main evaluation conditions of the catalyst are listed in Table 2, and the reaction product analysis is listed in Table 3.

[0077] Example 2

[0078] (I) Catalyst Preparation

[0079] (1) Select appropriate amounts of palladium chloride (H2PdCl4), chloroauric acid (HAuCl4) and pure water to prepare 250.0 ml of an aqueous solution containing 2.5 g of precious metals Pd and Au as impregnation solution A, wherein the mass ratio of Pd to Au is 1:0.5 and 100.0 g of activated carbon (sheet coconut shell carbon, size: 20±2 mesh, specific surface area: 1500±50 μm) is added. 2 / g, pore volume: 0.6±0.03cm 3 The mixture of / g) was impregnated at 70°C for 1 h on a rotary evaporator. After the solvent was evaporated under reduced pressure, the wet catalyst precursor was placed in a forced-air drying oven and dried at 110°C for 6 h to obtain catalyst precursor a.

[0080] (2) Mix 100.0g of catalyst precursor a with 200mL of 15% hydrazine hydrate (N2H4·H2O) solution (solid-liquid ratio 1g:2mL), let stand for 3h, filter and wash with water until pH is neutral, and dry at 120℃ for 3h to obtain reduced catalyst precursor b.

[0081] (3) Polyphenylene ether (C8H8O) is selected. n (Number average molecular weight Mn: 20000), prepare 250.0 ml of chloroform solution containing 0.5 g polyphenylene ether as impregnation solution B, wherein the concentration of polyphenylene ether is 2.0 g / L, mix with 125.0 g of reduced catalyst precursor b, let stand at room temperature for 6 h, place the wet catalyst in a forced-air drying oven, and dry at 60 °C for 24 h to obtain catalyst product c;

[0082] (II) Catalyst Performance Evaluation

[0083] The catalyst was evaluated using a 1L high-pressure autoclave reactor. The specific reaction and post-treatment steps were as follows:

[0084] a) Add 60.0g of pyromellitic acid (C) to a 1000ml autoclave. 10 H6O8 (purity: >98.0%), along with 340g of deionized water and 6.0g of catalyst product c, were added. Hydrogen gas was introduced into the high-pressure reactor and the hydrogen partial pressure was controlled at 7.0MPa. The temperature was controlled at 90℃, and the reaction was carried out for 24h.

[0085] b) Then cool to room temperature (20±5℃), discharge and filter. The catalyst is separated from the filter cake. The used catalyst is used to analyze the content of active components and calculate the loss rate of active components. After the filtrate is dehydrated by vacuum distillation, cyclohexanetetracarboxylic acid (HPMA) is precipitated. HPLC is used for quantitative analysis. The reaction conversion rate, selectivity, yield and purity are calculated based on the analysis results.

[0086] (III) Characterization of catalyst and support

[0087] a) The active components (Pd, Au) of the catalyst before and after evaluation were quantitatively analyzed using a Thermo iCAP 6300 inductively coupled plasma atomic emission spectrometer (ICP-AES), and the loss rate of the active components was calculated.

[0088] b) The total specific surface area and total adsorption pore volume of the carrier activated carbon were determined using a Micromeritics ASAP 2460 surface area and porosity analyzer.

[0089] For ease of comparison, the catalyst preparation conditions and catalyst composition are listed in Table 1, the main evaluation conditions of the catalyst are listed in Table 2, and the reaction product analysis is listed in Table 3.

[0090] Example 3

[0091] (I) Catalyst Preparation

[0092] (1) Select appropriate amounts of palladium chloride (H₂PdCl₄), chloroauric acid (HAuCl₄), and pure water to prepare 250.0 ml of an aqueous solution containing 0.5 g of precious metals Pd and Au, as impregnation solution A, where the mass ratio of Pd to Au is 1:0.5. Impregnation solution A is mixed with 100.0 g of activated carbon (sheet coconut shell carbon, size: 20±2 mesh, specific surface area: 1500±50 μm). 2 / g, pore volume: 0.6±0.03cm 3 The mixture of / g) was impregnated at 70°C for 1 h on a rotary evaporator. After the solvent was evaporated under reduced pressure, the wet catalyst precursor was placed in a forced-air drying oven and dried at 110°C for 6 h to obtain catalyst precursor a.

[0093] (2) Mix 100.0g of catalyst precursor a with 200mL of 15% hydrazine hydrate (N2H4·H2O) solution (solid-liquid ratio 1g:2mL), let stand for 3h, filter and wash with water until pH is neutral, and dry at 120℃ for 3h to obtain reduced catalyst precursor b.

[0094] (3) Polyphenylene ether (C8H8O) is selected. n(Number average molecular weight Mn: 20000), prepare 250.0 ml of chloroform solution containing 0.025 g polyphenylene ether as impregnation solution B, wherein the concentration of polyphenylene ether is 0.1 g / L, mix with 125.0 g of reduced catalyst precursor b, let stand at room temperature for 6 h, place the wet catalyst in a forced-air drying oven, and dry at 60 ℃ for 24 h to obtain catalyst product c;

[0095] (II) Catalyst Performance Evaluation

[0096] The catalyst was evaluated using a 1L high-pressure autoclave reactor. The specific reaction and post-treatment steps were as follows:

[0097] a) Add 60.0g of pyromellitic acid (C) to a 1000ml autoclave. 10 H6O8 (purity: >98.0%), along with 340g of deionized water and 6.0g of catalyst product c, were added. Hydrogen gas was introduced into the high-pressure reactor and the hydrogen partial pressure was controlled at 5.0MPa. The temperature was controlled at 50℃, and the reaction was carried out for 1 hour.

[0098] b) Then cool to room temperature (20±5℃), discharge and filter. The catalyst is separated from the filter cake. The used catalyst is used to analyze the content of active components and calculate the loss rate of active components. After the filtrate is dehydrated by vacuum distillation, cyclohexanetetracarboxylic acid (HPMA) is precipitated. HPLC is used for quantitative analysis. The reaction conversion rate, selectivity, yield and purity are calculated based on the analysis results.

[0099] (III) Characterization of catalyst and support

[0100] a) The active components (Pd, Au) of the catalyst before and after evaluation were quantitatively analyzed using a Thermo iCAP 6300 inductively coupled plasma atomic emission spectrometer (ICP-AES), and the loss rate of the active components was calculated.

[0101] b) The total specific surface area and total adsorption pore volume of the carrier activated carbon were determined using a Micromeritics ASAP 2460 surface area and porosity analyzer.

[0102] For ease of comparison, the catalyst preparation conditions and catalyst composition are listed in Table 1, the main evaluation conditions of the catalyst are listed in Table 2, and the reaction product analysis is listed in Table 3.

[0103] Example 4

[0104] (I) Catalyst Preparation

[0105] (1) Select appropriate amounts of palladium chloride (H₂PdCl₄), chloroauric acid (HAuCl₄), and pure water to prepare 250.0 ml of an aqueous solution containing 5.0 g of precious metals Pd and Au, as impregnation solution A, where the mass ratio of Pd to Au is 1:0.5. Impregnation solution A is mixed with 100.0 g of activated carbon (sheet coconut shell carbon, size: 20±2 mesh, specific surface area: 1500±50 μm). 2 / g, pore volume: 0.6±0.03cm 3 The mixture of / g) was impregnated at 70°C for 1 h on a rotary evaporator. After the solvent was evaporated under reduced pressure, the wet catalyst precursor was placed in a forced-air drying oven and dried at 110°C for 6 h to obtain catalyst precursor a.

[0106] (2) Mix 100.0g of catalyst precursor a with 200mL of 15% hydrazine hydrate (N2H4·H2O) solution (solid-liquid ratio 1g:2mL), let stand for 3h, filter and wash with water until pH is neutral, and dry at 120℃ for 3h to obtain reduced catalyst precursor b.

[0107] (3) Polyphenylene ether (C8H8O) is selected. n (Number average molecular weight Mn: 20000), prepare 250.0 ml of chloroform solution containing 0.75 g polyphenylene ether as impregnation solution B, wherein the concentration of polyphenylene ether is 3.0 g / L, mix with 125.0 g of reduced catalyst precursor b, let stand at room temperature for 6 h, place the wet catalyst in a forced-air drying oven, and dry at 60 ℃ for 24 h to obtain catalyst product c;

[0108] (II) Catalyst Performance Evaluation

[0109] The catalyst was evaluated using a 1L high-pressure autoclave reactor. The specific reaction and post-treatment steps were as follows:

[0110] a) Add 60.0g of pyromellitic acid (C) to a 1000ml autoclave. 10 H6O8 (purity: >98.0%), along with 340g of deionized water and 6.0g of catalyst product c, were added. Hydrogen gas was introduced into the high-pressure reactor and the hydrogen partial pressure was controlled at 10.0MPa. The temperature was controlled at 150℃ and the reaction was carried out for 100h.

[0111] b) Then cool to room temperature (20±5℃), discharge and filter. The catalyst is separated from the filter cake. The used catalyst is used to analyze the content of active components and calculate the loss rate of active components. After the filtrate is dehydrated by vacuum distillation, cyclohexanetetracarboxylic acid (HPMA) is precipitated. HPLC is used for quantitative analysis. The reaction conversion rate, selectivity, yield and purity are calculated based on the analysis results.

[0112] (III) Characterization of catalyst and support

[0113] a) The active components (Pd, Au) of the catalyst before and after evaluation were quantitatively analyzed using a Thermo iCAP 6300 inductively coupled plasma atomic emission spectrometer (ICP-AES), and the loss rate of the active components was calculated.

[0114] b) The total specific surface area and total adsorption pore volume of the carrier activated carbon were determined using a Micromeritics ASAP 2460 surface area and porosity analyzer.

[0115] For ease of comparison, the catalyst preparation conditions and catalyst composition are listed in Table 1, the main evaluation conditions of the catalyst are listed in Table 2, and the reaction product analysis is listed in Table 3.

[0116] Example 5

[0117] (I) Catalyst Preparation

[0118] (1) Select appropriate amounts of chloroplatinic acid (H2PtCl6), rhodium trichloride (RhCl3·3H2O), and pure water to prepare 250.0 ml of an aqueous solution containing 2.5 g of precious metals Pt and Au, as impregnation solution A, where the mass ratio of Pt to Rh is 1:0.5. Impregnation solution A is mixed with 100.0 g of activated carbon (sheet coconut shell carbon, size: 20±2 mesh, specific surface area: 1500±50 μm). 2 / g, pore volume: 0.6±0.03cm 3 The mixture of / g) was impregnated at 70°C for 1 h on a rotary evaporator. After the solvent was evaporated under reduced pressure, the wet catalyst precursor was placed in a forced-air drying oven and dried at 110°C for 6 h to obtain catalyst precursor a.

[0119] (2) Mix 100.0g of catalyst precursor a with 200mL of 15% hydrazine hydrate (N2H4·H2O) solution (solid-liquid ratio of 1g:2mL), let stand for 3h, filter and wash with water until pH value is neutral, and dry at 120℃ for 3h to obtain reduced catalyst precursor b.

[0120] (3) Polyphenylene ether (C8H8O) is selected. n (Number average molecular weight Mn: 20000), prepare 250.0 ml of chloroform solution containing 0.5 g polyphenylene ether as impregnation solution B, wherein the concentration of polyphenylene ether is 2.0 g / L, mix with 125.0 g of reduced catalyst precursor b, let stand at room temperature for 6 h, place the wet catalyst in a forced-air drying oven, and dry at 60 °C for 24 h to obtain catalyst product c;

[0121] (II) Catalyst Performance Evaluation

[0122] The catalyst was evaluated using a 1L high-pressure autoclave reactor. The specific reaction and post-treatment steps were as follows:

[0123] a) Add 60.0g of pyromellitic acid (C) to a 1000ml autoclave. 10 H6O8 (purity: >98.0%), along with 340g of deionized water and 6.0g of catalyst product c, were added. Hydrogen gas was introduced into the high-pressure reactor and the hydrogen partial pressure was controlled at 7.0MPa. The temperature was controlled at 90℃, and the reaction was carried out for 24h.

[0124] b) Then cool to room temperature (20±5℃), discharge and filter. The catalyst is separated from the filter cake. The used catalyst is used to analyze the content of active components and calculate the loss rate of active components. After the filtrate is dehydrated by vacuum distillation, cyclohexanetetracarboxylic acid (HPMA) is precipitated. HPLC is used for quantitative analysis. The reaction conversion rate, selectivity, yield and purity are calculated based on the analysis results.

[0125] (III) Characterization of catalyst and support

[0126] a) The active components (Pt, Rh) of the catalyst before and after evaluation were quantitatively analyzed using a Thermo iCAP 6300 inductively coupled plasma atomic emission spectrometer (ICP-AES), and the loss rate of the active components was calculated.

[0127] b) The total specific surface area and total adsorption pore volume of the carrier activated carbon were determined using a Micromeritics ASAP 2460 surface area and porosity analyzer.

[0128] For ease of comparison, the catalyst preparation conditions and catalyst composition are listed in Table 1, the main evaluation conditions of the catalyst are listed in Table 2, and the reaction product analysis is listed in Table 3.

[0129] Comparative Example 1

[0130] (I) Catalyst Preparation

[0131] (1) Select appropriate amounts of palladium chloride (H₂PdCl₄), chloroauric acid (HAuCl₄), and pure water to prepare 250.0 ml of an aqueous solution containing 2.5 g of precious metals Pd and Au, as impregnation solution A, where the mass ratio of Pd to Au is 1:0.5. Impregnation solution A is mixed with 100.0 g of activated carbon (sheet coconut shell carbon, size: 20±2 mesh, specific surface area: 1500±50 μm). 2 / g, pore volume: 0.6±0.03cm 3 The mixture of / g) was impregnated at 70°C for 1 h on a rotary evaporator. After the solvent was evaporated under reduced pressure, the wet catalyst precursor was placed in a forced-air drying oven and dried at 110°C for 6 h to obtain catalyst precursor a.

[0132] (2) Mix 100.0g of catalyst precursor a with 200mL of 15% hydrazine hydrate (N2H4·H2O) solution (solid-liquid ratio of 1g:2mL), let stand for 3h, filter and wash with water until the pH value is neutral, and dry at 120℃ for 3h to obtain catalyst product c;

[0133] (II) Catalyst Performance Evaluation

[0134] The catalyst was evaluated using a 1L high-pressure autoclave reactor. The specific reaction and post-treatment steps were as follows:

[0135] a) Add 60.0g of pyromellitic acid (C) to a 1000ml autoclave. 10 H6O8 (purity: >98.0%), along with 340g of deionized water and 6.0g of catalyst product c, were added. Hydrogen gas was introduced into the high-pressure reactor and the hydrogen partial pressure was controlled at 7.0MPa. The temperature was controlled at 90℃, and the reaction was carried out for 24h.

[0136] b) Then cool to room temperature (20±5℃), discharge and filter. The catalyst is separated from the filter cake. The used catalyst is used to analyze the content of active components and calculate the loss rate of active components. After the filtrate is dehydrated by vacuum distillation, cyclohexanetetracarboxylic acid (HPMA) is precipitated. HPLC is used for quantitative analysis. The reaction conversion rate, selectivity, yield and purity are calculated based on the analysis results.

[0137] (III) Characterization of catalyst and support

[0138] a) The active components (Pd, Au) of the catalyst before and after evaluation were quantitatively analyzed using a Thermo iCAP 6300 inductively coupled plasma atomic emission spectrometer (ICP-AES), and the loss rate of the active components was calculated.

[0139] b) The total specific surface area and total adsorption pore volume of the carrier activated carbon were determined using a Micromeritics ASAP 2460 surface area and porosity analyzer.

[0140] For ease of comparison, the catalyst preparation conditions and catalyst composition are listed in Table 1, the main evaluation conditions of the catalyst are listed in Table 2, and the reaction product analysis is listed in Table 3.

[0141] Comparative Example 2

[0142] (I) Catalyst Preparation

[0143] (1) Select appropriate amounts of palladium chloride (H₂PdCl₄), chloroauric acid (HAuCl₄), and pure water to prepare 250.0 ml of an aqueous solution containing 2.5 g of precious metals Pd and Au, as impregnation solution A, where the mass ratio of Pd to Au is 1:0.5. Impregnation solution A is mixed with 100.0 g of activated carbon (sheet coconut shell carbon, size: 20±2 mesh, specific surface area: 1500±50 μm). 2 / g, pore volume: 0.6±0.03cm 3 The mixture of / g) was impregnated at 70°C for 1 h on a rotary evaporator. After the solvent was evaporated under reduced pressure, the wet catalyst precursor was placed in a forced-air drying oven and dried at 110°C for 6 h to obtain catalyst precursor a.

[0144] (2) Mix 100.0g of catalyst precursor a with 200mL of 15% hydrazine hydrate (N2H4·H2O) solution (solid-liquid ratio of 1g:2mL), let stand for 3h, filter and wash with water until pH value is neutral, and dry at 120℃ for 3h to obtain reduced catalyst precursor b.

[0145] (3) Phenolic resin (C8H8O2) is selected. n Prepare 250.0 ml of ethanol solution containing 0.5 g of phenolic resin as impregnation solution B, wherein the concentration of phenolic resin is 2.0 g / L, mix with 125.0 g of reduced catalyst precursor b, let stand at room temperature for 6 h, place the wet catalyst in a forced-air drying oven, and dry at 80 ℃ for 24 h to obtain catalyst product c.

[0146] (II) Catalyst Performance Evaluation

[0147] The catalyst was evaluated using a 1L high-pressure autoclave reactor. The specific reaction and post-treatment steps were as follows:

[0148] a) Add 60.0g of pyromellitic acid (C) to a 1000ml autoclave. 10 H6O8 (purity: >98.0%), along with 340g of deionized water and 6.0g of catalyst product c, were added. Hydrogen gas was introduced into the high-pressure reactor and the hydrogen partial pressure was controlled at 7.0MPa. The temperature was controlled at 90℃, and the reaction was carried out for 24h.

[0149] b) Then cool to room temperature (20±5℃), discharge and filter. The catalyst is separated from the filter cake. The used catalyst is used to analyze the content of active components and calculate the loss rate of active components. After the filtrate is dehydrated by vacuum distillation, cyclohexanetetracarboxylic acid (HPMA) is precipitated. HPLC is used for quantitative analysis. The reaction conversion rate, selectivity, yield and purity are calculated based on the analysis results.

[0150] (III) Characterization of catalyst and support

[0151] a) The active components (Pd, Au) of the catalyst before and after evaluation were quantitatively analyzed using a Thermo iCAP 6300 inductively coupled plasma atomic emission spectrometer (ICP-AES), and the loss rate of the active components was calculated.

[0152] b) The total specific surface area and total adsorption pore volume of the carrier activated carbon were determined using a Micromeritics ASAP 2460 surface area and porosity analyzer.

[0153] For ease of comparison, the catalyst preparation conditions and catalyst composition are listed in Table 1, the main evaluation conditions of the catalyst are listed in Table 2, and the reaction product analysis is listed in Table 3.

[0154] Comparative Example 3

[0155] (I) Catalyst Preparation

[0156] (1) Select appropriate amounts of palladium chloride (H₂PdCl₄), chloroauric acid (HAuCl₄), and pure water to prepare 250.0 ml of an aqueous solution containing 2.5 g of precious metals Pd and Au, as impregnation solution A, where the mass ratio of Pd to Au is 1:0.5. Impregnation solution A is mixed with 100.0 g of activated carbon (sheet coconut shell carbon, size: 20±2 mesh, specific surface area: 1500±50 μm). 2 / g, pore volume: 0.6±0.03cm 3 / g) Mix and impregnate at 70°C for 1 hour on a rotary evaporator. After evaporating the solvent under reduced pressure, place the wet catalyst precursor in a forced-air drying oven and dry at 110°C for 6 hours to obtain catalyst precursor a.

[0157] (2) Mix 100.0g of catalyst precursor a with 200mL of 15% hydrazine hydrate (N2H4·H2O) solution (solid-liquid ratio of 1g:2mL), let stand for 3h, filter and wash with water until pH value is neutral, and dry at 120℃ for 3h to obtain reduced catalyst precursor b.

[0158] (3) Polyvinylpyrrolidone (C6H9NO) was selected. n (Number average molecular weight Mn: 20000), prepare 250.0 ml of an aqueous solution containing 0.5 g of polyvinylpyrrolidone as impregnation solution B, wherein the concentration of polyvinylpyrrolidone is 2.0 g / L, mix with 125.0 g of reduced catalyst precursor b, let stand at room temperature for 6 h, place the wet catalyst in a forced-air drying oven, and dry at 80 ℃ for 24 h to obtain catalyst product c;

[0159] (II) Catalyst Performance Evaluation

[0160] The catalyst was evaluated using a 1L high-pressure autoclave reactor. The specific reaction and post-treatment steps were as follows:

[0161] a) Add 60.0g of pyromellitic acid (C) to a 1000ml autoclave. 10 H6O8 (purity: >98.0%), along with 340g of deionized water and 6.0g of catalyst product c, were added. Hydrogen gas was introduced into the high-pressure reactor and the hydrogen partial pressure was controlled at 7.0MPa. The temperature was controlled at 90℃, and the reaction was carried out for 24h.

[0162] b) Then cool to room temperature (20±5℃), discharge and filter. The catalyst is separated from the filter cake. The used catalyst is used to analyze the content of active components and calculate the loss rate of active components. After the filtrate is dehydrated by vacuum distillation, cyclohexanetetracarboxylic acid (HPMA) is precipitated. HPLC is used for quantitative analysis. The reaction conversion rate, selectivity, yield and purity are calculated based on the analysis results.

[0163] (III) Characterization of catalyst and support

[0164] a) The active components (Pd, Au) of the catalyst before and after evaluation were quantitatively analyzed using a Thermo iCAP 6300 inductively coupled plasma atomic emission spectrometer (ICP-AES), and the loss rate of the active components was calculated.

[0165] b) The total specific surface area and total adsorption pore volume of the carrier activated carbon were determined using a Micromeritics ASAP 2460 surface area and porosity analyzer.

[0166] For ease of comparison, the catalyst preparation conditions and catalyst composition are listed in Table 1, the main evaluation conditions of the catalyst are listed in Table 2, and the reaction product analysis is listed in Table 3.

[0167] Comparative Example 4

[0168] (I) Catalyst Preparation

[0169] (1) Select appropriate amounts of palladium chloride (H₂PdCl₄), chloroauric acid (HAuCl₄), and pure water to prepare 250.0 ml of an aqueous solution containing 2.5 g of precious metals Pd and Au, as impregnation solution A, where the mass ratio of Pd to Au is 1:0.5. Impregnation solution A is mixed with 100.0 g of activated carbon (sheet coconut shell carbon, size: 20±2 mesh, specific surface area: 1500±50 μm). 2 / g, pore volume: 0.6±0.03cm 3 The mixture of / g) was impregnated at 70°C for 1 h on a rotary evaporator. After the solvent was evaporated under reduced pressure, the wet catalyst precursor was placed in a forced-air drying oven and dried at 110°C for 6 h to obtain catalyst precursor a.

[0170] (2) Mix 100.0g of catalyst precursor a with 200mL of 15% hydrazine hydrate (N2H4·H2O) solution (solid-liquid ratio of 1g:2mL), let stand for 3h, filter and wash with water until pH value is neutral, and dry at 120℃ for 3h to obtain reduced catalyst precursor b.

[0171] (3) Polyphenylene ether (C8H8O) is selected. n (Number average molecular weight Mn: 35000), prepare 250.0 ml of chloroform solution containing 0.5 g polyphenylene ether as impregnation solution B, wherein the concentration of polyphenylene ether is 2.0 g / L, mix with 125.0 g of reduced catalyst precursor b, let stand at room temperature for 6 h, place the wet catalyst in a forced-air drying oven, and dry at 60 °C for 24 h to obtain catalyst product c;

[0172] (II) Catalyst Performance Evaluation

[0173] The catalyst was evaluated using a 1L high-pressure autoclave reactor. The specific reaction and post-treatment steps were as follows:

[0174] a) Add 60.0g of pyromellitic acid (C) to a 1000ml autoclave. 10 H6O8 (purity: >98.0%), along with 340g of deionized water and 6.0g of catalyst product c, were added. Hydrogen gas was introduced into the high-pressure reactor and the hydrogen partial pressure was controlled at 7.0MPa. The temperature was controlled at 90℃, and the reaction was carried out for 24h.

[0175] b) Then cool to room temperature (20±5℃), discharge and filter. The catalyst is separated from the filter cake. The used catalyst is used to analyze the content of active components and calculate the loss rate of active components. After the filtrate is dehydrated by vacuum distillation, cyclohexanetetracarboxylic acid (HPMA) is precipitated. HPLC is used for quantitative analysis. The reaction conversion rate, selectivity, yield and purity are calculated based on the analysis results.

[0176] (III) Characterization of catalyst and support

[0177] a) The active components (Pd, Au) of the catalyst before and after evaluation were quantitatively analyzed using a Thermo iCAP 6300 inductively coupled plasma atomic emission spectrometer (ICP-AES), and the loss rate of the active components was calculated.

[0178] b) The total specific surface area and total adsorption pore volume of the carrier activated carbon were determined using a Micromeritics ASAP 2460 surface area and porosity analyzer.

[0179] For ease of comparison, the catalyst preparation conditions and catalyst composition are listed in Table 1, the main evaluation conditions of the catalyst are listed in Table 2, and the reaction product analysis is listed in Table 3.

[0180] Table 1. Catalyst preparation and characterization

[0181]

[0182] Table 2. Catalyst Evaluation Conditions

[0183]

[0184] Table 3. Analysis of reaction products

[0185] Conversion rate / % Selectivity / % purity / % Loss rate of active ingredients / % Example 1 99.5 98.6 98.1 0.5 Example 2 99.4 98.3 97.5 0.2 Example 3 98.4 98.1 97.1 0.3 Example 4 98.9 98.4 96.5 0.8 Example 5 99.0 97.9 97.6 0.9 Comparative Example 1 98.2 98.3 97.8 10.8 Comparative Example 2 98.0 98.5 96.1 8.1 Comparative Example 3 97.2 95.8 97.4 9.8 Comparative Example 4 97.4 98.2 97.9 5.6

[0186] Any numerical value mentioned in this invention, if there is only a two-unit interval between any minimum and any maximum value, includes all values ​​that increase by one unit each time from the minimum to the maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, or time, is stated as 50-90, in this specification it means specifically listing values ​​such as 51-89, 52-88… and 69-71 and 70-71, etc. For non-integer values, it may be appropriately considered that a unit is 0.1, 0.01, 0.001, or 0.0001. These are merely some specifically specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0187] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for synthesizing cyclohexane tetra carboxylic acid, characterized by, A raw material containing pyromellitic acid and H2 reacts in the presence of a catalyst to yield cyclohexanetetracarboxylic acid. The catalyst comprises a support, a noble metal, and an additive; the noble metal is selected from at least one of Pd, Au, Pt, Rh, and Ru; the additive is polyphenylene ether. The number average molecular weight M of the polyphenylene ether is 10,000 to 30,000. n is 10,000 to 30,000.

2. The method of synthesis of claim 1, wherein, The content of the precious metal in the catalyst is 2.0~20.0 g / L, calculated as precious metal element, and the content of the polyphenylene ether in the catalyst is 0.1~3.0 g / L. And / or, the bulk density of the catalyst is 400~600 g / L.

3. The method of synthesis of claim 1, wherein, The precious metal is a mixture of Pd and Au.

4. The method of synthesis of claim 3, wherein, The mass ratio of Pd to Au in the mixture is 1:(0.1~1).

5. The method of synthesis of claim 4, wherein, The mass ratio of Pd to Au in the mixture is 1:(0.1~0.5).

6. The method of synthesis of claim 1, wherein, The carrier is selected from at least one of activated carbon, SiO2, Al2O3, and TiO2.

7. The method of synthesis of claim 6, wherein, The activated carbon is coconut shell carbon.

8. The method of synthesis of claim 1, wherein, The specific surface area of the carrier is 1000-2000 m 2 The total pore volume of the carrier is 0.5-1.0 cm 3 / g.

9. The method of synthesis according to any one of claims 1 to 8, wherein, The method for preparing the catalyst includes: (1) Mix solution I containing noble metal salt with the support and dry to obtain catalyst precursor A; (2) Reduce catalyst precursor A to obtain catalyst precursor B; (3) The catalyst precursor B is mixed with solution II containing polyphenylene ether and dried to obtain the catalyst.

10. The method of synthesis of claim 9, wherein, In step (1), the precious metal salt is selected from at least one of the hydrochloride, nitrate or acetate of a precious metal; And / or, in step (1), the concentration of the noble metal in the solution I containing the noble metal salt is 2.0~20.0 g / L; And / or, in step (1), the solvent in the solution I containing the noble metal salt is water; And / or, in step (1), the solid-liquid ratio of the carrier to solution I containing the noble metal salt is 1 g: (1~10) mL; And / or, in step (2), the reduction is a solution reduction method or a gas reduction method; And / or, in step (3), the concentration of polyphenylene ether in the solution II containing polyphenylene ether is 0.1~10.0 g / L; And / or, in step (3), the solvent in the solution II containing polyphenylene ether is chloroform; And / or, in step (3), the solid-liquid ratio of the catalyst precursor B to the solution II containing polyphenylene ether is 1 g: (1~5) mL.

11. The method of synthesis of claim 10, wherein, The reducing agent in the solution reduction method is selected from hydrazine hydrate or sodium formate.

12. The method of synthesis of claim 9, wherein, The reaction conditions include: a reaction temperature of 50~150℃; And / or, the reaction time is 1.0~100.0 h; And / or, the partial pressure of H2 in the reaction is 5.0~10.0 MPa.

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