Hydroxyquinoline coordinated catalyst, preparation method, composite catalyst and application

Abstract

The invention discloses a hydroxyquinoline coordinated catalyst, a preparation method, a composite catalyst and application, the general formula of the hydroxyquinoline coordinated catalyst is shown as formula (I), in the formula (I), B is selected from one of metal cations, ammonium ions, quaternary ammonium salt cations and quaternary phosphonium salt cations, M is one of Mo, W, Cr and Mn, R is C1-C10 alkyl, x is an integer between 1 and 20, and y is an integer between 1 and 40. The hydroxyquinoline coordinated catalyst provided by the invention has high activity and high selectivity, and has high catalytic action and high conversion effect in catalytic oxidation of phenolic compounds to prepare quinone compounds.

Description

Technical Field

[0001] This invention belongs to the field of organic chemistry technology, specifically relating to catalysts for hydroxyquinoline coordination, preparation methods, composite catalysts, and applications. Background Technology

[0002] Quinones are a class of aromatic organic compounds with a six-carbon cyclic diketone structure containing two double bonds. They possess the properties of open-chain diketones and can undergo addition, substitution, and reduction reactions. Common quinones include benzoquinone, naphthoquinone, and phenanthrenequinone. Benzoquinone and its derivatives have antibacterial and anti-inflammatory properties and can be used to treat various diseases, finding applications in drug and dye synthesis. Naphthoquinone has various pharmacological effects, including anti-inflammatory and antitumor activity, and can be used to treat hepatitis, rheumatoid arthritis, and other diseases. Phenanthrenequinone can be used as an intermediate in vat dyes and as a photoconductive material in electrophotography.

[0003] Common synthetic methods for quinones include: benzoquinone preparation via the oxidation of phenols; naphthoquinone preparation via the oxidation of naphthalene; and phenanthrenequinone preparation via the oxidation of phenanthrene. For example, US Patent US10364231B and European Patent EP2014 / 063425 disclose the oxidation of trimethylphenol to trimethylbenzoquinone using oxygen-containing gas based on copper chloride. This involves the use of large amounts of copper chloride or chloride compounds with added lithium chloride, but often results in the formation of chlorination byproducts. These byproducts decompose and release HCl during post-processing, leading to equipment corrosion. Another example is the use of TiSBA-15 molecular sieve as a catalyst and hydrogen peroxide as an oxidant to oxidize p-2-methyl-1-naphthol into quinone. However, the preparation of this molecular sieve is complex and costly. Yet another example is the use of heteropolyacids as catalysts and hydrogen peroxide as an oxidant to oxidize trimethylphenol and naphthol to prepare quinones. However, the heteropolyacids used in this technology are complex, difficult to prepare, and impractical for practical application.

[0004] It is evident that the methods described above for preparing quinone compounds from phenolic compounds all suffer from drawbacks such as the large amount of catalyst used, the limited number of catalyst reuses, and the potential for equipment corrosion due to the reaction system.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide catalysts, preparation methods, composite catalysts and applications for hydroxyquinoline coordination. The hydroxyquinoline coordination catalysts of this invention have high activity and high selectivity, can be reused repeatedly, and can effectively catalyze the oxidation of phenolic compounds to quinone compounds.

[0007] To achieve the above objectives, a specific embodiment of the present invention provides the following technical solution:

[0008] A hydroxyquinoline-coordinated catalyst, the catalyst having the general formula shown in formula (I):

[0009] (I)

[0010] Wherein, B is selected from one of the following: metal cation, ammonium ion, quaternary ammonium salt cation, and quaternary phosphorus salt cation;

[0011] M is one of Mo, W, Cr, and Mn;

[0012] R is C1~C 10 alkyl;

[0013] x is an integer between 1 and 20;

[0014] y is an integer between 1 and 40.

[0015] In one or more embodiments of the present invention, the quaternary ammonium salt cation is one of tetrabutylammonium ion, tetramethylammonium ion, hexadecyltrimethylammonium ion, dodecyltrimethylammonium ion, and octadecyltrimethylammonium ion.

[0016] In one or more embodiments of the present invention, the metal cation is one of lithium ion, sodium ion, potassium ion, magnesium ion, and calcium ion.

[0017] In one or more embodiments of the present invention, the quaternary phosphonium salt cation is benzyltriphenylphosphonium ion.

[0018] Another specific embodiment of the present invention provides the following technical solution:

[0019] A method for preparing a hydroxyquinoline-coated catalyst includes the following steps:

[0020] The metal compound is dissolved in deionized water, and the pH of the solution is adjusted to 1-4; then peroxide and deionized water are added to the solution to obtain a metal peroxide solution.

[0021] An alkyl-substituted 5-chloro-8-hydroxyquinoline and a salt were added to a metal peroxide solution, and the mixture was stirred, centrifuged, filtered, and dried to obtain a catalyst with hydroxyquinoline coordination as shown in formula (I).

[0022] Another specific embodiment of the present invention provides the following technical solution:

[0023] A composite catalyst comprising the above-mentioned hydroxyquinoline coordinated catalyst.

[0024] In one or more embodiments of the present invention, the composite catalyst further includes a co-catalyst, wherein the weight ratio of the hydroxyquinoline-coated catalyst to the co-catalyst is 100:(1~500).

[0025] The co-catalyst is one or more of the following: cerium nitrate, cerium sulfate, cerium acetate, manganese acetate, manganese nitrate, manganese sulfate, vanadium oxide, cobalt oxide, silver nitrate, zirconium oxide, zirconium acetate, ferric nitrate, ferric sulfate, ferric chloride, copper sulfate, copper acetate, copper nitrate, magnesium sulfate, magnesium acetate, zinc acetate, zinc sulfate, sodium molybdate, potassium acetate, and potassium sulfate.

[0026] In one or more embodiments of the present invention, the composite catalyst further includes a modifier, wherein the weight ratio of the hydroxyquinoline-coordinated catalyst to the modifier is 100:(1~500).

[0027] The regulator is one or more of phosphomolybdic acid, phosphotungstic acid, tetrabutylammonium bromide, boric acid, silicotungstic acid, and phosphomolybdic vanadate.

[0028] In one or more embodiments of the present invention, the composite catalyst further includes a protective agent, wherein the weight ratio of the hydroxyquinoline-coordinated catalyst to the protective agent is 100:(1~500).

[0029] The protective agent is one or more of sodium acetate, ammonium bromide, hexadecyltrimethylammonium bromide, phenyltrimethylammonium bromide, sodium molybdate, and N-hydroxyphthalimide.

[0030] In one or more embodiments of the present invention, the composite catalyst is dissolved in an organic solvent before use, and the weight ratio of the hydroxyquinoline-coated catalyst to the organic solvent is 100:(50~50000).

[0031] The organic solvent is one or more of 1,4-dioxane, acetonitrile, methanol, ethanol, n-butanol, isobutanol, and n-pentanol.

[0032] Another specific embodiment of the present invention provides the following technical solution:

[0033] Application of a hydroxyquinoline-coated catalyst or a composite catalyst in the preparation of quinone compounds from oxidized phenolic compounds.

[0034] In one or more embodiments of the present invention, the method for preparing quinone compounds by oxidizing phenolic compounds is as follows:

[0035] Phenolic compounds and reaction solvents are added to a reaction vessel, followed by a hydroxyquinoline-coated catalyst or a composite catalyst. Air is introduced into the reaction vessel at a rate of 1-10 mL / s, and the reaction is stirred at 50-110°C for 1-10 h.

[0036] Compared with existing technologies, the hydroxyquinoline-coordinated catalyst of this invention has a bidentate structure, enabling effective coordination with metals. The chlorine at the 5-position of the quinoline ring effectively enhances the activation of the para-position of phenol, thereby significantly improving the catalyst's activity and selectivity. Furthermore, the B-selective cation in the catalyst possesses both hydrophilic and hydrophobic properties, effectively enhancing the catalyst's lipophilicity and hydrophilicity, promoting catalyst-substrate contact, and ultimately improving conversion efficiency. Detailed Implementation

[0037] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention are clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0038] A specific embodiment of the present invention provides a hydroxyquinoline-coordinated catalyst, the catalyst structure of which is shown in formula (I): In formula (I), B is selected from one of the following: metal cation, ammonium ion, quaternary ammonium salt cation, and quaternary phosphonium salt cation; M is one of Mo, W, Cr, and Mn; and R is Cl~C 10 Alkyl group, where x is an integer between 1 and 20, and y is an integer between 1 and 40.

[0039] Specifically, the chemical structure in formula (I) contains a bidentate structure. The oxygen and nitrogen atoms substituted at the 8-position of the quinoline ring simultaneously coordinate with metal M (in a +6 valence state), effectively forming a stable complex and ensuring catalytic activity and selectivity. The chlorine atom substituted at the 5-position of the quinoline ring further enhances the catalytic activity and selectivity of the catalyst, effectively increasing the activation of phenolic compounds and promoting the reaction when catalyzing the formation of quinone compounds from phenolic compounds. The alkyl group substituted at the 2-position of the quinoline ring can affect the selectivity and catalytic activity of the catalyst; in this invention, C1~C1 is selected. 10 Alkyl groups, as R groups, can improve the selectivity and catalytic activity of catalysts, making them more suitable for catalyzing the formation of quinones from phenolic compounds.

[0040] Furthermore, the selection of type B in this invention can enhance the oleophilicity and hydrophilicity of the catalyst, promoting contact between the catalyst and the reaction substrate and improving the conversion efficiency. Simultaneously, this invention limits the values ​​of x and y to improve the stability of the catalyst structure and enhance the interaction between the catalyst and the reaction substrate, thereby effectively improving the catalytic activity, selectivity, and stability of the catalyst.

[0041] In one specific embodiment, the quaternary ammonium salt cation is one of tetrabutylammonium ion, tetramethylammonium ion, hexadecyltrimethylammonium ion, dodecyltrimethylammonium ion, and octadecyltrimethylammonium ion; the metal cation is one of lithium ion, sodium ion, potassium ion, magnesium ion, and calcium ion; and the quaternary phosphonium salt cation is benzyltriphenylphosphonium ion.

[0042] More preferably, B is one of dodecyltrimethylammonium ion, octadecyltrimethylammonium ion, lithium ion, sodium ion, potassium ion, magnesium ion, calcium ion, ammonium ion, and benzyltriphenylphosphonium ion; M is one of Mo and Cr; R is a C1~C5 alkyl group; x is an integer between 1 and 5; and y is an integer between 1 and 5.

[0043] More preferably, B is one of octadecyltrimethylammonium ion, sodium ion, magnesium ion, ammonium ion, and benzyltriphenylphosphonium ion; M is one of Mo and Cr; R is methyl, ethyl, or isopropyl; x is 1, and y is 1 or 2.

[0044] Specifically, by selecting specific types of B and M, and limiting the values ​​of x and y, the catalysts coordinated with hydroxyquinoline exhibit higher selectivity and catalytic activity in the preparation of quinone compounds from phenolic compounds.

[0045] Another specific embodiment of the present invention provides a method for preparing a hydroxyquinoline coordinated catalyst, including steps 1-2.

[0046] Step 1: Dissolve the metal compound in deionized water and adjust the pH of the solution to 1-4; then add peroxide and deionized water to the solution to obtain a metal peroxide solution.

[0047] Specifically, the metal compound is dissolved in deionized water at room temperature, and the pH of the solution is adjusted using sulfuric acid, phosphoric acid, hydrochloric acid, or nitric acid. The metal compound is one of sodium molybdate, ammonium chromate, potassium manganate, or sodium manganate, and the peroxide is one or more of hydrogen peroxide, m-chloroperoxybenzoic acid, tert-butyl hydroperoxide, and urea peroxide.

[0048] Step 2: Add alkyl-substituted 5-chloro-8-hydroxyquinoline and salt to the metal peroxide solution, stir, centrifuge, filter, and dry to obtain a hydroxyquinoline coordinated catalyst with the chemical structure shown in formula (I).

[0049] Specifically, the metal peroxide solution is first heated to 25-100°C, and then the hydroxyquinoline compound and salt are added. The alkyl-substituted 5-chloro-8-hydroxyquinoline is 3-methyl-5-chloro-8-hydroxyquinoline, 3-ethyl-5-chloro-8-hydroxyquinoline, 3-propyl-5-chloro-8-hydroxyquinoline, 3-isopropyl-5-chloro-8-hydroxyquinoline, 3-n-butyl-5-chloro-8-hydroxyquinoline, 3-tert-butyl-5-chloro-8-hydroxyquinoline, or 3-isobutyl-5-chloro-8-hydroxyquinoline; the salt is octadecyltrimethylammonium chloride, octadecyltrimethylammonium bromide, or octadecyltrimethylammonium chloride. One of lithium, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, ammonium bromide, dodecyl dimethyl benzyl ammonium bromide, dodecyl trimethyl ammonium chloride, octadecyl dimethyl benzyl ammonium bromide, octyltributylphosphonium bromide, tetrabutylphosphonium bromide, hexyltributylphosphonium bromide, tributylethylphosphonium bromide, tetrabutylphosphonium bromide, tributylhexylphosphonium bromide, tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, benzyltrimethylammonium chloride, benzyltriphenylphosphine bromide, and benzyltriethylammonium chloride.

[0050] Another specific embodiment of the present invention provides a composite catalyst, including a catalyst coordinated with hydroxyquinoline as shown in formula (I).

[0051] Preferably, the composite catalyst further includes a co-catalyst, a regulator, and a protectant, and the weight ratio of the hydroxyquinoline-coordinated catalyst, co-catalyst, regulator, and protectant is 100:(1~500):(1~500):(1~500).

[0052] Specifically, the co-catalyst is one or more of cerium nitrate, cerium sulfate, cerium acetate, manganese acetate, manganese nitrate, manganese sulfate, vanadium oxide, cobalt oxide, silver nitrate, zirconium oxide, zirconium acetate, ferric nitrate, ferric sulfate, ferric chloride, copper sulfate, copper acetate, copper nitrate, magnesium sulfate, magnesium acetate, zinc acetate, zinc sulfate, sodium molybdate, potassium acetate, and potassium sulfate; the regulator is one or more of phosphomolybdic acid, phosphotungstic acid, tetrabutylammonium bromide, boric acid, silicotungstic acid, and phosphomolybdic vanadate; and the protectant is one or more of sodium acetate, ammonium bromide, hexadecyltrimethylammonium bromide, phenyltrimethylammonium bromide, sodium molybdate, and N-hydroxyphthalimide.

[0053] Specifically, selecting the aforementioned types of cocatalysts can improve reaction selectivity, promote the oxidation of specific phenolic hydroxyl groups to quinones, activate phenolic compounds, and accelerate the reaction rate. These regulators can influence the reaction rate and progress; adding them to the reaction system in a certain proportion can effectively promote the reaction and improve reaction efficiency. Protective agents in the reaction system can reduce the occurrence of side reactions, improve the yield and purity of the target product, and to a certain extent, activate phenolic hydroxyl groups, making them easier to oxidize, while also preventing over-oxidation.

[0054] In one specific embodiment, the composite catalyst is dissolved in an organic solvent before use, and the weight ratio of the hydroxyquinoline-coated catalyst to the organic solvent is 100:(50~10000).

[0055] Specifically, the organic solvent is one or more of 1,4-dioxane, acetonitrile, methanol, ethanol, n-butanol, isobutanol, and n-pentanol. Selecting one of these organic solvents to dissolve the composite catalyst first can promote its uniform dispersion in the reaction system, increase the reaction rate, and reduce the occurrence of side reactions.

[0056] More preferably, the weight ratio of the hydroxyquinoline-coordinated catalyst, co-catalyst, regulator, protectant, and organic solvent is 100:(1~50):(1~500):(10~100):(100~1000), the co-catalyst is one or more of manganese acetate, zirconium acetate, magnesium acetate, and cerium acetate, the regulator is one or more of phosphomolybdic acid, phosphotungstic acid, and silicotungstic acid, the protectant is one or more of ammonium bromide, hexadecyltrimethylammonium bromide, phenyltrimethylammonium bromide, and N-hydroxyphthalimide, and the organic solvent is one or more of acetonitrile, ethanol, n-butanol, isobutanol, and n-pentanol.

[0057] Another specific embodiment of the present invention provides the application of the hydroxyquinoline coordinated catalyst or composite catalyst shown in formula (I) in the preparation of quinone compounds from oxidized phenolic compounds.

[0058] In one specific embodiment, the method for preparing quinone compounds by oxidizing phenolic compounds is as follows: phenolic compounds and reaction solvents are added to a reaction vessel, and then a catalyst or composite catalyst containing hydroxyquinoline coordination is added. Air is introduced into the reaction vessel at a rate of 1~10 mL / s, and the reaction is stirred at 50~110°C for 1~10 h.

[0059] Specifically, taking a composite catalyst as an example, the amount of composite catalyst used is 0.01~5% of the weight of phenolic compound. The composite catalyst includes a catalyst, co-catalyst, regulator and protectant with a weight ratio of 100:(1~500):(1~500):(1~500); the phenolic compound is phenol, methylphenol, p-methylphenol, naphthol or methylnaphthol; the reaction solvent is ethanol, n-butanol or n-pentanol.

[0060] In a further preferred embodiment, air is introduced into the reactor at a rate of 2-5 mL / s, and the reaction is stirred at 60-90°C for 2-5 h; the reaction solvent is n-butanol, and the amount of composite catalyst is 0.1-1% of the weight of the phenolic compound.

[0061] Specifically, the hydroxyquinoline-coordinated catalyst shown in formula (I) of this invention has high selectivity and high catalytic activity in the reaction of oxidizing phenolic compounds to prepare quinones. When added to the reaction system in a certain proportion, it can selectively oxidize phenolic hydroxyl groups to generate quinones with a high conversion rate.

[0062] The present invention will be further described in detail below with reference to specific embodiments.

[0063] Examples of catalysts coordinated with hydroxyquinoline

[0064] Example 1

[0065] At room temperature, 20.60 g of sodium molybdate was added to 500 mL of deionized water and stirred until completely dissolved. Dilute sulfuric acid was then added dropwise to adjust the pH to 2, and stirring continued for 30 min. 200 mL of a 30% hydrogen peroxide solution was slowly added to the solution, followed by the addition of deionized water until the total volume reached 3000 mL, yielding a metal peroxide solution.

[0066] The metal peroxide solution was heated to 50°C. 19.36 g of 3-methyl-5-chloro-8-hydroxyquinoline and 76.57 g of tetrabutylammonium bromide were added to the solution, and the mixture was heated and stirred for 1 hour. The mixture was then centrifuged for 10 minutes, filtered, and the resulting solid was dried in a vacuum oven to obtain 59.82 g of a yellow solid. This yellow solid is the hydroxyquinoline-coordinated catalyst. The NMR characterization data are as follows:

[0067] 1 H NMR: δ 2.29-2.39 (3H, 2.34 (s), 2.34 (s), 2.34 (s)), 2.81 (12H,s), 7.31 (1H, d, J = 8.5 Hz), 7.63 (1H, dd, J = 8.5, 0.5 Hz), 8.47 (1H, dd, J = 1.7, 0.5 Hz), 8.62 (1H, d, J = 1.7 Hz).

[0068] Example 2

[0069] At room temperature, 20.60 g of sodium molybdate was added to 500 mL of deionized water and stirred until completely dissolved. Dilute sulfuric acid was then added dropwise to adjust the pH to 2, and stirring continued for 30 min. 200 mL of a 30% urea peroxide solution was slowly added to the solution, followed by the addition of deionized water until the total volume reached 3000 mL, yielding a metal peroxide solution.

[0070] The metal peroxide solution was heated to 50°C. 22.11 g of 3-isopropyl-5-chloro-8-hydroxyquinoline and 42.25 g of octadecyltrimethylammonium chloride were added to the solution, and the mixture was heated and stirred for 1 hour. The mixture was then centrifuged for 10 minutes, filtered, and the resulting solid was dried in a vacuum oven to obtain 58.87 g of a yellow solid, which is the hydroxyquinoline-coordinated catalyst. The NMR characterization data are as follows:

[0071] 1 H NMR: δ 0.86 (3H, t, J = 7.0 Hz), 1.13-1.43 (36H, m), 1.94 (2H,quint, J = 7.4 Hz), 2.84 (9H, s), 3.05 (2H, t, J = 7.4 Hz), 3.23 (1H, sept, J= 6.9 Hz), 7.31 (1H, d, J = 8.4 Hz), 7.63 (1H, dd, J = 8.4, 0.5 Hz), 8.22 (1H, dd, J = 1.9, 0.5 Hz), 8.73 (1H, d, J = 1.9 Hz).

[0072] Example 3

[0073] At room temperature, 15.2 g of ammonium chromate was added to 500 mL of deionized water and stirred until completely dissolved. Dilute sulfuric acid was then added dropwise to adjust the pH of the solution to 2, and stirring was continued for 120 min. 200 mL of 30% hydrogen peroxide solution was slowly added to the solution, followed by the addition of deionized water until the total volume of the solution was 3000 mL, yielding a metal peroxide solution.

[0074] The metal peroxide solution was heated to 30°C. 19.36 g of 3-ethyl-5-chloro-8-hydroxyquinoline and 42.25 g of octadecyltrimethylammonium chloride were added to the solution, and the mixture was heated and stirred for 1 hour. The mixture was then centrifuged for 30 minutes, filtered, and the resulting solid was dried in a vacuum oven to obtain 32.46 g of a purplish-red solid. This purplish-red solid is the catalyst coordinated with hydroxyquinoline. The NMR characterization data are as follows:

[0075] 1H NMR: δ 0.86 (3H, t, J = 7.0 Hz), 1.09-1.43 (33H, m), 1.94 (2H,quint, J = 7.4 Hz), 2.78-2.90 (11H, 2.84 (q, J = 6.9 Hz), 2.84 (q, J = 6.9Hz), 2.84 (s)), 3.05 (2H, t, J = 7.4 Hz), 7.31 (1H, d, J = 8.4 Hz), 7.63 (1H,dd, J = 8.4, 0.5 Hz), 8.25 (1H, dd, J = 1.8, 0.5 Hz), 8.73 (1H, d, J = 1.8Hz).

[0076] Examples of catalyst applications using hydroxyquinoline coordination

[0077] Application Example 1

[0078] 0.1g of the hydroxyquinoline-coated catalyst from Example 1, 0.01g of cerium acetate, 0.01g of phosphomolybdic acid, 0.01g of sodium acetate, and 50g of ethanol were added sequentially to a 250mL titanium high-pressure reactor. After the reactor was assembled, nitrogen gas was introduced until the internal pressure reached 0.5MPa and maintained for 15 minutes. If the pressure drop did not exceed 5%, the reactor was considered to have good airtightness. After purging the nitrogen, the reactor temperature was raised to 65℃, and air was introduced until the internal pressure reached 0.3MPa. Air was continuously introduced at a flow rate of 400mL / min. After the system stabilized, a methanol solution of phenol was pumped in at a rate of 1mL / min using a high-pressure feed pump. The methanol solution contained 30% phenol by weight. The total amount of material pumped in was 100mL. After pumping, the reaction continued for 1 hour. After the reaction was completed, the reaction solution was yellow-green, and the total weight of the reaction solution was 138.73g.

[0079] Take 0.1 g of the reaction solution, use xylene as an internal standard, dilute with 30 g of acetonitrile, and then perform liquid chromatography analysis. The calculated conversion rate of phenol was 99.3%, and the selectivity for benzoquinone was 92.35%.

[0080] Application Example 2

[0081] 0.1g of the hydroxyquinoline-coated catalyst from Example 2, 0.01g of cerium acetate, 0.01g of phosphomolybdic acid, 0.01g of sodium acetate, and 50g of n-butanol were added sequentially to a 250mL titanium high-pressure reactor. After the reactor was assembled, nitrogen gas was introduced until the internal pressure reached 0.5MPa and maintained for 15 minutes. If the pressure drop did not exceed 5%, the reactor was considered to have good airtightness. After purging the nitrogen, the reactor temperature was raised to 70°C, and air was introduced until the internal pressure reached 0.3MPa. Air was continuously introduced at a flow rate of 400mL / min. After the system stabilized, a methanol solution of o-methylphenol was pumped in at a rate of 1mL / min using a high-pressure feed pump. The o-methylphenol content in the methanol solution was 30% by weight. The total amount of material pumped in was 100mL. After pumping, the reaction continued for 1 hour. After the reaction was completed, the reaction solution was yellow-green, and the total weight of the reaction solution was 134.63g.

[0082] Take 0.1 g of the reaction solution, use xylene as an internal standard, dilute with 30 g of acetonitrile, and then perform liquid chromatography analysis. The calculated conversion rate of o-methylphenol was 98.6%, and the selectivity of methylbenzoquinone was 93.38%.

[0083] Application Example 3

[0084] 0.1g of the hydroxyquinoline-coated catalyst from Example 3, 0.01g of cerium acetate, 0.01g of phosphomolybdic acid, 0.01g of sodium acetate, and 50g of n-pentanol were added sequentially to a 250mL titanium high-pressure reactor. After the reactor was assembled, nitrogen gas was introduced until the internal pressure reached 0.5MPa and maintained for 15 minutes. If the pressure drop did not exceed 5%, the reactor was considered to have good airtightness. After purging the nitrogen, the reactor temperature was raised to 60℃, and air was introduced until the internal pressure reached 0.3MPa. Air was continuously introduced at a flow rate of 400mL / min. After the system stabilized, a naphthol n-pentanol solution was pumped in at a rate of 1mL / min using a high-pressure feed pump. The naphthol content in the n-pentanol solution was 30% by weight. The total amount of material pumped in was 100mL. After pumping, the reaction continued for 1 hour. After the reaction was completed, the reaction solution was yellow-green, and the total weight of the reaction solution was 134.63g.

[0085] Take 0.1 g of the reaction solution, use xylene as an internal standard, dilute with 30 g of acetonitrile, and then perform liquid chromatography analysis. The calculated conversion rate of naphthol was 98.96%, and the selectivity of naphthoquinone was 91.36%.

[0086] Comparative Example 1

[0087] At room temperature, 20.60 g of sodium molybdate was added to 500 mL of deionized water and stirred until completely dissolved. Dilute sulfuric acid was then added dropwise to adjust the pH to 2, and stirring continued for 30 min. 200 mL of a 30% hydrogen peroxide solution was slowly added to the solution, followed by the addition of deionized water until the total volume reached 3000 mL, yielding a metal peroxide solution.

[0088] The metal peroxide solution was heated to 50°C. 17.51 ​​g of 3-methyl-8-hydroxyquinoline and 76.57 g of tetrabutylammonium bromide were added to the solution, and the mixture was heated and stirred for 1 hour. The mixture was then centrifuged for 10 minutes, filtered, and the resulting solid was dried in a vacuum oven to obtain 53.35 g of a yellow solid, which is the hydroxyquinoline-coordinated catalyst. The NMR characterization data are as follows:

[0089] 1 H NMR: δ 2.29-2.39 (3H, 2.34 (s), 2.34 (s), 2.34 (s)), 2.81 (12H,s), 7.31 (1H, d, J = 8.5 Hz), 7.63 (1H, dd, J = 8.5, 0.5 Hz), 8.47 (1H, dd, J = 1.7, 0.5 Hz), 8.62 (1H, d, J = 1.7 Hz).

[0090] 0.1g of hydroxyquinoline-coated catalyst, 0.01g of cerium acetate, 0.01g of phosphomolybdic acid, 0.01g of sodium acetate, and 50g of n-pentanol were added sequentially to a 250mL titanium high-pressure reactor. After the reactor was assembled, nitrogen gas was introduced until the internal pressure reached 0.5MPa and maintained for 15 minutes. If the pressure drop did not exceed 5%, the reactor was considered to have good airtightness. After purging the nitrogen, the reactor temperature was raised to 60℃, and air was introduced until the internal pressure reached 0.3MPa. Air was continuously introduced at a flow rate of 400mL / min. After the system stabilized, a naphthol n-pentanol solution was pumped in at a rate of 1mL / min using a high-pressure feed pump. The naphthol content in the n-pentanol solution was 30% by weight. The total amount of material pumped in was 100mL. After pumping, the reaction continued for 1 hour. After the reaction was completed, the reaction solution was yellow-green, and the total weight of the reaction solution was 134.63g.

[0091] Take 0.1 g of the reaction solution, use xylene as an internal standard, dilute with 30 g of acetonitrile, and then perform liquid chromatography analysis. The calculated conversion rate of naphthol was 68.76%, and the selectivity of naphthoquinone was 67.65%.

[0092] Comparative Example 2

[0093] At room temperature, 20.60 g of sodium molybdate was added to 500 mL of deionized water and stirred until completely dissolved. Dilute sulfuric acid was then added dropwise to adjust the pH to 2, and stirring continued for 30 min. 200 mL of a 30% urea peroxide solution was slowly added to the solution, followed by the addition of deionized water until the total volume reached 3000 mL, yielding a metal peroxide solution.

[0094] The metal peroxide solution was heated to 50°C. 18.32 g of 3-isopropyl-8-hydroxyquinoline and 42.25 g of octadecyltrimethylammonium chloride were added to the solution, and the mixture was heated and stirred for 1 hour. The mixture was then centrifuged for 10 minutes, filtered, and the resulting solid was dried in a vacuum oven to obtain 55.65 g of a yellow solid, which is the hydroxyquinoline-coordinated catalyst. The NMR characterization data are as follows:

[0095] 1 H NMR: δ 0.86 (3H, t, J = 7.0 Hz), 1.13-1.43 (36H, m), 1.94 (2H,quint, J = 7.4 Hz), 2.84 (9H, s), 3.05 (2H, t, J = 7.4 Hz), 3.23 (1H, sept, J= 6.9 Hz), 7.31 (1H, d, J = 8.4 Hz), 7.63 (1H, dd, J = 8.4, 0.5 Hz), 8.22 (1H, dd, J = 1.9, 0.5 Hz), 8.73 (1H, d, J = 1.9 Hz).

[0096] 0.1g of hydroxyquinoline-coated catalyst, 0.01g of cerium acetate, 0.01g of phosphomolybdic acid, 0.01g of sodium acetate, and 50g of ethanol were added sequentially to a 250mL titanium high-pressure reactor. After the reactor was assembled, nitrogen gas was introduced until the internal pressure reached 0.5MPa and maintained for 15 minutes. If the pressure drop did not exceed 5%, the reactor was considered to have good airtightness. After purging the nitrogen, the reactor temperature was raised to 65℃, and air was introduced until the internal pressure reached 0.3MPa. Air was continuously introduced at a flow rate of 400mL / min. After the system stabilized, a methanol solution of phenol was pumped in at a rate of 1mL / min using a high-pressure feed pump. The methanol solution contained 30% phenol by weight. The total amount of material pumped in was 100mL. After the pumping was completed, the reaction continued for 1 hour. After the reaction was completed, the reaction solution was yellow-green, and the total weight of the reaction solution was 138.73g.

[0097] Take 0.1 g of the reaction solution, use xylene as an internal standard, dilute with 30 g of acetonitrile, and then perform liquid chromatography analysis. The calculated conversion rate of phenol was 67.3%, and the selectivity for benzoquinone was 72.5%.

[0098] Compared with Comparative Examples 1-2, the hydroxyquinoline-coated catalyst in the embodiments of the present invention was used to oxidize phenolic compounds to generate quinone compounds, and the conversion rate of phenolic compounds reached over 98%, demonstrating a high conversion effect. In contrast, the conversion rates of phenolic compounds in Comparative Examples 1-2 were all below 80%, far lower than the conversion rates in the application examples of the present invention. This indicates that the present invention selects alkyl-substituted 5-chloro-8-hydroxyquinoline as a raw material to prepare the catalyst, which can effectively enhance the activity and selectivity of the hydroxyquinoline-coated catalyst and effectively improve the conversion effect.

[0099] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0100] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A hydroxyquinoline-coordinated catalyst characterized by, The catalyst general formula is shown as formula (I): （I） B is selected from one of metal cation, ammonium ion, quaternary ammonium salt cation, quaternary phosphonium salt cation; M is one of Mo, W, Cr, Mn; R is C1-C 10 alkyl; x is an integer between 1 and 20; y is an integer between 1 and 40.

2. The hydroxyquinoline-liganded catalyst according to claim 1, characterized in that, The quaternary ammonium salt cation is one of tetrabutylammonium ion, tetramethylammonium ion, hexadecyltrimethylammonium ion, dodecyltrimethylammonium ion, octadecyltrimethylammonium ion.

3. The hydroxyquinoline-liganded catalyst according to claim 1, wherein The metal cation is one of lithium ion, sodium ion, potassium ion, magnesium ion, calcium ion.

4. The hydroxyquinoline-liganded catalyst of claim 1, wherein The quaternary phosphonium salt cation is benzyltriphenylphosphonium ion.

5. A process for the preparation of a catalyst coordinated with a hydroxyquinoline according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: Dissolve the metal compound in deionized water, adjust the pH of the solution to 1-4, add peroxide and deionized water to the solution to obtain a metal peroxide solution; Add alkyl-substituted 5-chloro-8-hydroxyquinoline and salt to the metal peroxide solution, stir, centrifuge, filter, and dry to obtain the hydroxyquinoline-coordinated catalyst of the general formula shown as formula (I).

6. A composite catalyst characterized by comprising The method comprises the following steps:

7. The composite catalyst according to claim 6, wherein The composite catalyst further comprises an auxiliary catalyst, and the weight ratio of the hydroxyquinoline-coordinated catalyst to the auxiliary catalyst is 100: (1-500); The auxiliary catalyst is one or more of cerium nitrate, cerium sulfate, cerium acetate, manganese acetate, manganese nitrate, manganese sulfate, vanadium oxide, cobalt oxide, silver nitrate, zirconium oxide, zirconium acetate, iron nitrate, iron sulfate, iron chloride, copper sulfate, copper acetate, copper nitrate, magnesium sulfate, magnesium acetate, zinc acetate, zinc sulfate, sodium molybdate, potassium acetate, and potassium sulfate.

8. The composite catalyst according to claim 6, wherein The composite catalyst further comprises a regulator, and the weight ratio of the hydroxyquinoline-coordinated catalyst to the regulator is 100: (1-500); The regulator is one or more of phosphomolybdic acid, phosphotungstic acid, tetrabutylammonium bromide, boric acid, silicotungstic acid, and phosphomolybdovanadic acid.

9. The composite catalyst according to claim 6, wherein The composite catalyst further comprises a protective agent, and the weight ratio of the hydroxyquinoline-coordinated catalyst to the protective agent is 100: (1-500); The protective agent is one or more of sodium acetate, ammonium bromide, hexadecyltrimethylammonium bromide, phenyltrimethylammonium bromide, sodium molybdate, and N-hydroxyphthalimide.

10. The composite catalyst according to claim 6, wherein The composite catalyst is dissolved in an organic solvent before use, and the weight ratio of the hydroxyquinoline-coordinated catalyst to the organic solvent is 100: (50-50000); The organic solvent is one or more of 1,4-dioxane, acetonitrile, methanol, ethanol, n-butanol, isobutanol, and n-pentanol.

11. Use of the hydroxyquinoline-coordinated catalyst of any one of claims 1-4 or the composite catalyst of any one of claims 6-10 in the oxidation of a phenolic compound to prepare a quinone compound.

12. Use of a hydroxyquinoline-coordinated catalyst according to claim 11, characterized in that The method for preparing a quinone compound by oxidizing a phenolic compound comprises the following steps: Add the phenolic compound and a reaction solvent to a reaction kettle, add the hydroxyquinoline-coordinated catalyst or the composite catalyst, and introduce air into the reaction kettle at a speed of 1-10 mL / s, and stir the reaction at 50-110°C for 1-10 h.

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