A method for preparing a catechol compound, a catalyst for preparing a catechol compound

Abstract

The application discloses a preparation method of a catechol compound and a catalyst for preparing the catechol compound, and the preparation method comprises the following steps: allowing p-alkyl phenol to occur catalytic oxidation reaction in the presence of an oxidant and the catalyst to generate the catechol compound; wherein the method for preparing the catalyst comprises the following steps: dispersing a titanium source and a pyridine carboxylic acid compound in a solvent to prepare a mixed solution, and then performing a hydrothermal reaction to generate the catalyst, and the catalyst is a metal organic framework material; the method can not only synthesize the catechol compound in one step, but also can realize less waste, has high selectivity and high conversion rate, and especially, the operation difficulty is remarkably reduced, the reaction can be performed under relatively mild conditions, the requirement for a production device is relatively low, and the method is suitable for industrial large-scale production.

Description

Technical Field

[0001] This invention relates to the field of fine chemical technology, and more particularly to the synthesis of fragrances and flavorings (such as jasmine aldehyde) or their intermediates, specifically to a method for preparing catechol compounds and a catalyst for preparing catechol compounds. Background Technology

[0002] 4-Methylcatechol is a widely used organic compound that serves as an important intermediate in many chemicals, including fragrances, pharmaceuticals, pesticides, dyes, and antioxidants. For example, 4-methylcatechol can be used as an important intermediate in the preparation of hesperidin. Chinese patent CN100335476C provides a process for synthesizing hesperidin from 4-methylcatechol via ring closure, chlorination, and hydrolysis. However, the route for synthesizing 4-methylcatechol from p-methylphenol in this patent is long, the process is complex, and the overall reaction yield is low.

[0003] Meanwhile, 4-methylcatechol can also be synthesized in one step using p-cresol as a raw material through hydrogen peroxide oxidation under different conditions. For example, there are reports of synthesizing 4-methylcatechol by hydroxylating p-cresol with hydrogen peroxide using titanium silicate molecular sieve as a catalyst, but the conversion rate is only about 30% at most, resulting in high production costs for 4-methylcatechol. There are also reports of synthesizing 4-methylcatechol using p-cresol as a raw material and hydrogen peroxide as an oxidant under the catalysis of arsenic or antimony compounds; however, this method has a very low conversion rate and requires highly toxic compounds as catalysts. There are also reports of using hydrogen peroxide for nucleohydroxylation of phenols in the presence of strong acids, but the acids used are sulfuric acid or perchloric acid, which severely corrodes the equipment, and the yield is less than 30%.

[0004] To improve the yield, one report describes a method using p-cresol as a starting material. The p-cresol acetate is acylated to produce p-cresol acetate, which is then subjected to the Fries rearrangement in a high-boiling-point inert solvent to yield 2-hydroxy-5-methylacetophenone. This is followed by alkalization to form a salt, low-temperature oxidation, and reduction and acidification of the reaction solution. The crude product is then extracted and concentrated, and purified 4-methylcatechol is obtained by distillation. The reaction route is as follows:

[0005]

[0006] Although this method improves the yield, it requires three reaction steps, which is too many. The second step needs to be carried out at a high temperature of 100-160℃, which consumes a lot of energy. In addition, it uses acid and alkali solutions multiple times, resulting in a lot of wastewater, which is not conducive to environmental protection. Summary of the Invention

[0007] The purpose of this invention is to overcome one or more shortcomings of the prior art and provide an improved method for preparing catechol compounds (including 4-methylcatechol). This method can not only synthesize catechol compounds in one step, but also achieves low waste, mild operating conditions, and high yield.

[0008] The present invention also provides a catalyst, which is a metal-organic framework material, and can be used as a catalyst in the catalytic oxidation of p-alkylphenol to prepare catechol compounds.

[0009] To achieve the above objectives, the present invention employs the following technical solution:

[0010] A method for preparing a catechol compound, the method comprising: subjecting the compound of formula (I) to a catalytic oxidation reaction in the presence of an oxidant and a catalyst to generate a catechol compound having the structure of formula (II);

[0011] In equations (I) and (II), R1 is selected from C. 1-6 alkyl;

[0012] The method for preparing the catalyst includes: dispersing a titanium source and a pyridine carboxylic acid compound having the structure shown in formula (III) in a solvent to obtain a mixed solution, and then carrying out a hydrothermal reaction to generate the catalyst;

[0013] In equation (Ⅲ), t is selected from 1 or 2.

[0014] According to some preferred aspects of the invention, the titanium source is alkyl ol titanium.

[0015] According to some preferred and specific aspects of the invention, the alkyl alkoxide titanium is titanium isopropoxide and / or titanium tetra-n-butoxide.

[0016] According to some preferred and specific aspects of the invention, the pyridine carboxylic acid compound is one or more of the following: 2,4-pyridinedicarboxylic acid, 2,3-pyridinedicarboxylic acid, 2,5-pyridinedicarboxylic acid, 2-pyridinecarboxylic acid, 3-pyridinecarboxylic acid, 4-pyridinecarboxylic acid, and 5-pyridinecarboxylic acid.

[0017] According to some preferred aspects of the invention, the molar ratio of titanium in the titanium source to the pyridine carboxylic acid compound is 1:1-6.

[0018] Furthermore, the molar ratio of titanium in the titanium source to the pyridine carboxylic acid compound is 1:2-4.

[0019] According to some preferred aspects of the invention, the solvent is composed of an alcohol solvent and an amide solvent, wherein the volume ratio of the alcohol solvent to the amide solvent is 1:1-6. Further, the volume ratio of the alcohol solvent to the amide solvent is 1:2-3.

[0020] According to some preferred aspects of the invention, the mass ratio of the titanium source to the alcohol solvent is 1:10-80. More preferably, the mass ratio of the titanium source to the alcohol solvent is 1:30-50.

[0021] In some embodiments of the present invention, the amide solvent comprises N-methylpyrrolidone (NMP).

[0022] In some embodiments of the present invention, the alcohol solvent is one or more selected from methanol, ethanol, isopropanol, butanol, and n-pentanol. According to some preferred and specific aspects of the present invention, the alcohol solvent is isopropanol.

[0023] According to some preferred aspects of the invention, the temperature of the hydrothermal reaction is controlled to be 130-190°C.

[0024] Furthermore, the temperature of the hydrothermal reaction is controlled to be 145-180℃.

[0025] According to some specific aspects of the invention, the temperature of the hydrothermal reaction is controlled to be 150-170°C, and further to 155-165°C.

[0026] According to some preferred aspects of the invention, the hydrothermal reaction time is controlled to be 10-25 h, more preferably 12-20 h.

[0027] In some preferred embodiments of the present invention, the preparation of the catalyst includes: dispersing the titanium source and the pyridine carboxylic acid compound in the solvent, stirring under heating conditions to obtain the mixed solution, transferring the mixed solution to a sealed reaction vessel, and then placing it in a hydrothermal reactor for hydrothermal reaction, and after the hydrothermal reaction is completed, cooling, filtering, washing, and drying to obtain the catalyst.

[0028] Furthermore, the washing is performed using alcohol solvents and amide solvents, or a mixture of alcohol solvents and amide solvents.

[0029] Furthermore, the drying is carried out under vacuum conditions at 50-70°C. Even further, the drying time can be 3-8 hours.

[0030] According to certain aspects of the present invention, embodiments for preparing the catalyst include:

[0031] (1) Weigh a certain amount of Ti source and pyridine carboxylic acid compound, dissolve them in a mixed solvent of amide solvent and alcohol solvent, and stir with a magnetic stirrer at 30-40℃ to make them fully mixed and homogeneous to obtain a mixed solution;

[0032] (2) The mixed solution obtained in step (1) was transferred to a polytetrafluoroethylene liner at room temperature, sealed and placed in a hydrothermal reactor, and then transferred to a forced-air drying oven for hydrothermal crystallization at 165-175℃ for 12-20 hours. After the hydrothermal reaction was completed, the hydrothermal reactor was naturally cooled to room temperature and then opened. The hydrothermal reaction solution was filtered under reduced pressure and then thoroughly washed with a certain amount of alcohol solvent and amide solvent to obtain a white powder solid.

[0033] (3) The white powdery solid obtained in step (2) is dried in a vacuum drying oven to obtain the catalyst.

[0034] According to some preferred aspects of the invention, the catalyst is added in a mass percentage of 0.1%-10%, more preferably 0.1%-5%, and even more preferably 0.2%-3.5% of the mass of the compound represented by formula (I).

[0035] In some embodiments of the present invention, the oxidant is hydrogen peroxide, and further, the hydrogen peroxide is added in the form of its aqueous solution (hydrogen peroxide).

[0036] According to some preferred and specific aspects of the invention, the molar ratio of the oxidant (e.g., hydrogen peroxide) to the compound represented by formula (I) is 3 to 6:1.

[0037] According to the present invention, the method can be carried out under relatively mild temperature conditions. According to some preferred and specific aspects of the present invention, the catalytic oxidation reaction is controlled to proceed at a temperature of 50-85°C, further at 55-80°C, and even further at 65-75°C.

[0038] In some embodiments of the present invention, the time for the catalytic oxidation reaction is controlled to be 1-10 h, and more specifically 2-8 h.

[0039] In some preferred embodiments of the present invention, the catalytic oxidation reaction is carried out by: mixing a solvent, the compound shown in formula (I), and a catalyst, heating to 50-85°C, adding an oxidant in batches, and continuing the reaction after the addition is complete. Further, according to some specific aspects of the present invention, the oxidant is added dropwise, and the dropwise addition time is further controlled to be 5-60 min, or 5-40 min, or 10-25 min.

[0040] In some embodiments of the present invention, the catechol compound is 4-methylcatechol, 4-ethylcatechol, 4-n-propylcatechol, 4-isopropylcatechol, or 4-tert-butylcatechol.

[0041] Another technical solution provided by the present invention: a catalyst for preparing catechol compounds, wherein the catalyst is a metal-organic framework material, and the preparation method of the metal-organic framework material includes:

[0042] A titanium source and a pyridine carboxylic acid compound having the structure shown in formula (Ⅲ) are dispersed in a solvent to prepare a mixed solution, and then subjected to a hydrothermal reaction to generate the catalyst.

[0043] In equation (Ⅲ), t is selected from 1 or 2.

[0044] Another technical solution provided by the present invention: the application of the above-mentioned metal-organic framework material as a catalyst in the catalytic oxidation of p-alkylphenol to prepare catechol compounds.

[0045] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0046] Based on the problems of multiple steps, low yield, large amounts of reaction waste, and easy corrosion of equipment in the existing preparation of catechol compounds such as 4-methylcatechol, the inventors of this invention unexpectedly discovered in practice that metal-organic framework materials Ti-MOFs can have excellent catalytic performance in the catalytic oxidation of p-alkylphenols to prepare catechol compounds. In particular, the improved Ti-MOFs prepared by using specific pyridine carboxylic acid compounds as organic ligands can not only catalytically oxidize and synthesize catechol compounds in one step, but also achieve the advantages of less waste, mild operating conditions, and high yield.

[0047] Through further experimental research and analysis, the inventors believe that the reason why the improved Ti-MOFs prepared by the specific method of this invention can achieve better technical results in the catalytic oxidation of p-alkylphenol to catechol compounds is that the Ti-MOFs contain metal nodes Ti 4+Its strong affinity for oxygen makes it more chemically stable and has excellent catalytic activity when constructing MOFs. In particular, the pyridine carboxylic acid compound, as an organic ligand, plays a regulatory role in the coordination structure of MOFs and the electron density of the metal center with the introduction of the pyridine ring containing the heteroatom N. It is expected to improve the electron state density of the metal Ti oxidation center and enhance its catalytic oxidation activity. Moreover, the various regulatory factors have a synergistic effect. The catalytic effect on the oxidation process of alkylphenols by specific raw materials is unexpectedly good. This makes the catalytic oxidation process of this invention highly selective and highly efficient. In particular, it significantly reduces the difficulty of operation. The reaction can be carried out under relatively mild conditions, with less waste and relatively low requirements for production equipment, making it suitable for large-scale industrial production. Detailed Implementation

[0048] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0049] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0050] Example 1

[0051] This example provides a method for preparing 4-methylcatechol using p-cresol as a starting material. The synthetic route is as follows:

[0052]

[0053] Specifically, the preparation method of 4-methylcatechol includes:

[0054] 15 mL of methanol solvent, 100 mmol of p-cresol, and 200 mg of Ti-MOF catalyst were added to a round-bottom flask. The mixture was stirred thoroughly with a magnetic stirrer and heated to 70 °C. 34.01 g of 30% hydrogen peroxide was added dropwise over 15 min. After the addition was complete, the reaction was continued for 4 h until the reaction was complete. Samples were taken and analyzed using an Agilent liquid chromatograph. The conversion rate of the raw material and the yield of the product were calculated using the external standard method. The external standard yield of 4-methylcatechol was 72%. After purification by distillation, 8.5 g of 4-methylcatechol was obtained (separation yield approximately 69%).

[0055] The Ti-MOFs catalyst was prepared by the following method:

[0056] (1) Weigh titanium isopropoxide (7.9 mmol, as titanium source) and 2,4-pyridinedicarboxylic acid (as organic ligand) in a molar ratio of 1:2. Then add titanium isopropoxide and 2,4-pyridinedicarboxylic acid to 87 mL of isopropanol (the mass ratio of titanium isopropoxide to isopropanol is about 1:31) and 174 mL of N-methylpyrrolidone (NMP) solvent to dissolve them. Stir at 35 °C for 3 hours to obtain a mixed solution.

[0057] (2) Transfer the above mixed solution into the polytetrafluoroethylene liner of the hydrothermal reactor, seal it and place it in a forced-air drying oven. The hydrothermal reaction is carried out at 160°C for 16 hours. After the reaction is completed, the reactor is allowed to cool naturally to room temperature and then opened. The reaction solution is filtered under reduced pressure and then washed with a mixed solution of 20 mL isopropanol and 40 mL N-methylpyrrolidone (NMP) (washed at 0°C) to obtain a white powdery wet solid sample.

[0058] (3) Place the sample in a vacuum drying oven and dry it under vacuum at 60°C for 5 hours. After drying, the Ti-MOFs catalyst can be obtained.

[0059] Example 2

[0060] This embodiment is basically the same as Example 1, except that the only difference is in the preparation process of the Ti-MOFs catalyst.

[0061] In step (1), titanium isopropoxide (7.9 mmol) and 2,4-pyridinedicarboxylic acid were weighed in a molar ratio of 1:4;

[0062] In step (1), the mass ratio of titanium isopropoxide to isopropanol is 1:10;

[0063] In step (1), the volume ratio of isopropanol to N-methylpyrrolidone is 1:6.

[0064] Example 3

[0065] This embodiment is basically the same as Example 1, except that the only difference is in the preparation process of the Ti-MOFs catalyst.

[0066] In step (1), titanium isopropoxide (7.9 mmol) and 2,4-pyridinedicarboxylic acid were weighed in a molar ratio of 1:6;

[0067] In step (1), the mass ratio of titanium isopropoxide to isopropanol is 1:80;

[0068] In step (1), the volume ratio of isopropanol to N-methylpyrrolidone is 1:1.

[0069] Example 4

[0070] This embodiment is basically the same as Example 1, except that 2,3-pyridinedicarboxylic acid is used as an organic ligand in the preparation of the Ti-MOFs catalyst.

[0071] In step (1), isopropanol is replaced with methanol, and the volume ratio of methanol to N-methylpyrrolidone is 1:2;

[0072] In step (1), the mass ratio of titanium isopropoxide to methanol is 1:30;

[0073] In step (1), titanium isopropoxide (7.9 mmol) and 2,3-pyridinedicarboxylic acid were weighed in a molar ratio of 1:2.

[0074] Example 5

[0075] This embodiment is basically the same as Example 1, except that 2,3-pyridinedicarboxylic acid is used as an organic ligand in the preparation of the Ti-MOFs catalyst.

[0076] In step (1), isopropanol is replaced with butanol, and the volume ratio of butanol to N-methylpyrrolidone is 1:6;

[0077] In step (1), the mass ratio of titanium isopropoxide to butanol is 1:10;

[0078] In step (1), titanium isopropoxide (7.9 mmol) and 2,3-pyridinedicarboxylic acid were weighed in a molar ratio of 1:4.

[0079] Example 6

[0080] This embodiment is basically the same as Example 1, except that 2,3-pyridinedicarboxylic acid is used as an organic ligand in the preparation of the Ti-MOFs catalyst.

[0081] In step (1), titanium isopropoxide (7.9 mmol) and 2,3-pyridinedicarboxylic acid were weighed in a molar ratio of 1:6;

[0082] In step (1), the mass ratio of titanium isopropoxide to isopropanol is 1:80;

[0083] In step (1), the volume ratio of isopropanol to N-methylpyrrolidone is 1:1.

[0084] Example 7

[0085] This embodiment is basically the same as Example 1, except that 2-pyridinecarboxylic acid is used as an organic ligand in the preparation of the Ti-MOFs catalyst.

[0086] In step (1), titanium isopropoxide (7.9 mmol) and 2-pyridinecarboxylic acid were weighed in a molar ratio of 1:4;

[0087] In step (1), the mass ratio of titanium isopropoxide to isopropanol is 1:20;

[0088] In step (1), the volume ratio of isopropanol to N-methylpyrrolidone is 1:3.

[0089] Example 8

[0090] This embodiment is basically the same as Example 1, except that 2-pyridinecarboxylic acid is used as an organic ligand in the preparation of the Ti-MOFs catalyst.

[0091] In step (1), isopropanol is replaced with n-pentanol, and the volume ratio of n-pentanol to N-methylpyrrolidone is 1:1;

[0092] In step (1), titanium isopropoxide (7.9 mmol) and 2-pyridinecarboxylic acid were weighed in a molar ratio of 1:4;

[0093] In step (1), the mass ratio of titanium isopropoxide to n-pentanol is 1:60.

[0094] Example 9

[0095] This embodiment is basically the same as Example 1, except that 2-pyridinecarboxylic acid is used as an organic ligand in the preparation of the Ti-MOFs catalyst.

[0096] In step (1), titanium isopropoxide (7.9 mmol) and 2-pyridinecarboxylic acid were weighed in a molar ratio of 1:6;

[0097] In step (1), the mass ratio of titanium isopropoxide to isopropanol is 1:40.

[0098] Example 10

[0099] This embodiment is basically the same as Example 1, except that: in the preparation process of the Ti-MOFs catalyst, titanium tetra-n-butoxide is used as the titanium source;

[0100] In step (1), tetrabutoxide titanium (7.9 mmol) and 2,4-pyridinedicarboxylic acid were weighed in a molar ratio of 1:2;

[0101] In step (1), the mass ratio of tetrabutoxide titanium to isopropanol is 1:30.

[0102] Example 11

[0103] This embodiment is basically the same as Example 1, except that the amount of Ti-MOF catalyst used in the preparation of 4-methylcatechol is 320 mg.

[0104] Example 12

[0105] This embodiment is basically the same as Example 1, except that the amount of Ti-MOF catalyst used in the preparation of 4-methylcatechol is 1080 mg.

[0106] Example 13

[0107] This embodiment is basically the same as Embodiment 1, except that 68.02g of hydrogen peroxide with a mass concentration of 30% is added during the preparation of 4-methylcatechol.

[0108] Example 14

[0109] This embodiment is basically the same as Embodiment 1, except that p-cresol is replaced with 4-ethylphenol.

[0110] Example 15

[0111] This embodiment is basically the same as Embodiment 1, except that p-cresol is replaced with 4-tert-butylphenol.

[0112] Comparative Example 1

[0113] This embodiment is basically the same as Example 1, except that 4-quinoline carboxylic acid is used in the preparation of the Ti-MOFs catalyst. As an organic ligand.

[0114] Comparative Example 2

[0115] This embodiment is basically the same as Example 1, except that terephthalic acid is used in the preparation of the Ti-MOFs catalyst. As an organic ligand.

[0116] Comparative Example 3

[0117] This embodiment is basically the same as Example 1, except that 2-aminoterephthalic acid is used in the preparation of the Ti-MOFs catalyst. As an organic ligand.

[0118] The conversion rate, selectivity, external standard yield, and separation yield of each implementation case in the above-described embodiments 1-15 and comparative examples 1-3 are statistically analyzed, as shown in Table 1.

[0119] Table 1

[0120]

[0121]

[0122] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0123] 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.

Claims

1. A method for preparing a catechol compound, characterized in that, The preparation method includes: subjecting the compound shown in formula (I) to a catalytic oxidation reaction in the presence of an oxidant and a catalyst to generate a catechol compound having the structure shown in formula (II), wherein the oxidant is hydrogen peroxide; In equations (I) and (II), R1 is selected from C. 1-6 alkyl; The method for preparing the catalyst includes: dispersing a titanium source and a pyridine carboxylic acid compound having the structure shown in formula (III) in a solvent to obtain a mixed solution, and then carrying out a hydrothermal reaction to generate the catalyst, wherein the titanium source is an alkyl ol titanium; In equation (Ⅲ), t is selected from 1 or 2.

2. The method for preparing the catechol compound according to claim 1, characterized in that, The alkyl alcohol titanium is titanium isopropoxide and / or titanium tetra-n-butoxide.

3. The method for preparing the catechol compound according to claim 1, characterized in that, The pyridine carboxylic acid compound is selected from one or more combinations of 2,4-pyridinedicarboxylic acid, 2,3-pyridinedicarboxylic acid, 2,5-pyridinedicarboxylic acid, 2-pyridinecarboxylic acid, 3-pyridinecarboxylic acid, 4-pyridinecarboxylic acid, and 5-pyridinecarboxylic acid; and / or, the molar ratio of titanium in the titanium source to the pyridine carboxylic acid compound is 1:1-6.

4. The method for preparing the catechol compound according to claim 1, characterized in that, The molar ratio of titanium in the titanium source to the pyridine carboxylic acid compound is 1:2-4.

5. The method for preparing the catechol compound according to claim 1, characterized in that, The solvent is composed of an alcohol solvent and an amide solvent, and the volume ratio of the alcohol solvent to the amide solvent is 1:1-6.

6. The method for preparing the catechol compound according to claim 5, characterized in that, The volume ratio of the alcohol solvent to the amide solvent is 1:2-3.

7. The method for preparing the catechol compound according to claim 5, characterized in that, The mass ratio of the titanium source to the alcohol solvent is 1:10-80.

8. The method for preparing the catechol compound according to claim 7, characterized in that, The mass ratio of the titanium source to the alcohol solvent is 1:30-50.

9. The method for preparing the catechol compound according to claim 5, characterized in that, The amide solvent includes N-methylpyrrolidone; the alcohol solvent is one or more combinations selected from methanol, ethanol, isopropanol, butanol, and n-pentanol.

10. The method for preparing the catechol compound according to claim 1, characterized in that, The temperature of the hydrothermal reaction is controlled at 130-190℃; and / or the time of the hydrothermal reaction is controlled at 10-25h; and / or, the preparation of the catalyst includes: dispersing the titanium source and the pyridine carboxylic acid compound in the solvent, stirring under heating conditions to obtain the mixed solution, transferring the mixed solution to a sealed reaction vessel, and then placing it in a hydrothermal reactor for hydrothermal reaction, and after the hydrothermal reaction is completed, cooling, filtering, washing, and drying to obtain the catalyst.

11. The method for preparing the catechol compound according to claim 1, characterized in that, The temperature of the hydrothermal reaction is controlled at 145-180℃.

12. The method for preparing the catechol compound according to claim 11, characterized in that, The temperature of the hydrothermal reaction is controlled at 150-170℃.

13. The method for preparing the catechol compound according to claim 1, characterized in that, The hydrothermal reaction time is controlled to be 12-20 hours.

14. The method for preparing the catechol compound according to claim 1, characterized in that, The catalyst is added at a mass percentage of 0.1%-10% of the mass of the compound shown in formula (I); and / or, the hydrogen peroxide is added in the form of its aqueous solution; and / or, the molar ratio of the oxidant to the compound shown in formula (I) is 3-6:1; and / or, the catalytic oxidation reaction is controlled at a temperature of 50-85°C; and / or, the catalytic oxidation reaction time is controlled at 1-10 h.

15. The method for preparing the catechol compound according to claim 1, characterized in that, The catalyst is added at a mass percentage of 0.1%-5% of the mass of the compound represented by formula (Ⅰ).

16. The method for preparing the catechol compound according to claim 15, characterized in that, The catalyst is added at a mass percentage of 0.2%-3.5% of the mass of the compound represented by formula (Ⅰ).

17. The method for preparing the catechol compound according to claim 1, characterized in that, The catalytic oxidation reaction is controlled to be carried out at a temperature of 55-80℃.

18. The method for preparing the catechol compound according to claim 17, characterized in that, The catalytic oxidation reaction is controlled to be carried out at a temperature of 65-75°C.

19. The method for preparing the catechol compound according to claim 1, characterized in that, The catalytic oxidation reaction is controlled to take 2-8 hours.

20. The method for preparing the catechol compound according to claim 1, characterized in that, The embodiment of the catalytic oxidation reaction includes: mixing the solvent, the compound shown in formula (Ⅰ) and the catalyst, heating to 50-85°C, adding the oxidant in batches, and continuing the reaction after the addition is complete.

21. The method for preparing the catechol compound according to claim 1, characterized in that, The catechol compound is 4-methylcatechol, 4-ethylcatechol, 4-n-propylcatechol, 4-isopropylcatechol, or 4-tert-butylcatechol.

22. A catalyst for preparing catechol compounds, characterized in that, The catalyst is a metal-organic framework material, and the preparation method of the metal-organic framework material includes: A titanium source and a pyridine carboxylic acid compound having the structure shown in formula (III) are dispersed in a solvent to prepare a mixed solution, and then a hydrothermal reaction is carried out to generate the catalyst, wherein the titanium source is alkyl ol titanium; In equation (Ⅲ), t is selected from 1 or 2.

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