A method for preparing epoxy cyclic hydrocarbons

Abstract

The present invention relates to a method for preparing epoxy cyclic hydrocarbons, which comprises: in the presence of a titanium-containing catalyst, contacting a cycloolefin and an oxidant to carry out an oxidation reaction; the titanium-containing catalyst is prepared by a method comprising the following steps: (1) placing a first conductive material and a second conductive material in an electrolyte containing an inorganic acid, and electrolyzing the electrolyte at a voltage of 30-100V for 2-10 days to obtain an electrolytic mixed solution; (2) mixing the electrolytic mixed solution, an organic silicate and a block copolymer, and maintaining the mixture at 50-100°C for 2-24 hours to obtain a first mixture; (3) mixing the first mixture, a titanium source and hydrogen peroxide, and maintaining the mixture at 60-90°C for 1-10 hours, hydrothermally treating the obtained second mixture, removing the solid, and drying and calcining the mixture. The titanium-containing catalyst prepared by the method of the present invention has excellent reaction activity, and its use in the oxidation reaction of cycloolefins can improve the conversion rate of raw materials and the selectivity for the target product.

Description

Technical Field

[0001] The present invention relates to a method for preparing epoxy cyclic hydrocarbons. Background Art

[0002] Nanocarbon materials such as carbon dots hold great promise for applications in the selective oxidation of hydrocarbons. However, existing carbon nanomaterials still require improvement and optimization in terms of material properties, necessitating further research and development by scientists and engineers to promote industrial upgrading and transformation in the petrochemical industry. In the selective oxidation of hydrocarbons, the production of oxygenated organic chemicals such as epoxy-cycloolefins plays a crucial role in national production, and existing catalytic oxidation production technologies are in urgent need of improvement in many aspects of their preparation. Summary of the Invention

[0003] The object of the present invention is to provide a method for preparing epoxy cyclic hydrocarbons, which can improve the conversion rate of raw materials and the selectivity of target products.

[0004] To achieve the above object, the present invention provides a method for preparing epoxy cyclic hydrocarbons, the method comprising: contacting a cycloolefin with an oxidant in the presence of a titanium-containing catalyst to carry out an oxidation reaction;

[0005] The titanium-containing catalyst is prepared by a method comprising the following steps:

[0006] (1) placing a first conductive material and a second conductive material connected to the positive electrode and the negative electrode of a DC power supply, respectively, in an electrolyte containing an inorganic acid, and electrolyzing them at a voltage of 30-100 V for 2-10 days to obtain an electrolytic mixed solution; wherein the first conductive material is a graphite rod, and the electrolytic mixed solution contains carbon dots;

[0007] (2) mixing the electrolytic mixed solution, the organic silicate and the block copolymer, and maintaining the mixture at 50-100° C. for 2-24 hours to obtain a first mixture; wherein the molecular weight of the block copolymer is 2000-100000;

[0008] (3) The first mixture, titanium source and hydrogen peroxide are mixed and maintained at 60-90° C. for 1-10 hours. The obtained second mixture is subjected to hydrothermal treatment, and the solid is taken out and dried and calcined.

[0009] Optionally, in step (1), the concentration of carbon dots in the electrolytic mixed solution is 10-1000 mg / L, and the concentration of inorganic acid in the electrolyte is 5-1000 mmol / L.

[0010] Optionally, in step (2), the electrolytic mixed solution is divided into a first part of the electrolytic mixed solution and a second part of the electrolytic mixed solution;

[0011] The organosilicate is mixed with the first part of the electrolytic mixed solution to obtain a third mixture, the block copolymer is mixed with the second part of the electrolytic mixed solution to obtain a fourth mixture, and the third mixture and the fourth mixture are mixed to obtain a first mixture.

[0012] Optionally, in step (2), the weight ratio of the electrolytic mixed solution, the organic silicate and the block copolymer is 100:(1-50):(1-40).

[0013] Optionally, in step (3), the weight ratio of the first mixture, the titanium source and the hydrogen peroxide solution is 1000:(1-500):(1-200).

[0014] Preferably, the weight ratio of the first mixture, the titanium source and the hydrogen peroxide is 100:(5-200):(2-100).

[0015] Optionally, in step (3), the drying is vacuum drying, and the conditions for the vacuum drying include: temperature of 20-200°C, pressure of 0-0.1 MPa, and time of 1-24 hours; the conditions for the calcination include: temperature of 400-800°C and time of 1-10 hours.

[0016] Optionally, the inorganic acid is selected from one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, hydrobromic acid, hydroiodic acid and sulfurous acid;

[0017] The organosilicate is selected from tetramethyl silicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate or dimethoxydiethoxysilane, or a combination of two or three thereof;

[0018] The titanium source is selected from one or more of titanium chloride, titanium sulfate, titanate, tetrabutyl titanate and tetrapropyl titanate;

[0019] The block copolymer is a polyethylene oxide-polypropylene oxide block copolymer, preferably P123 and / or F127.

[0020] Optionally, the oxidation reaction conditions include: temperature of 60-200° C., pressure of 0.1-5 MPa, and time of 0.1-24 hours.

[0021] Optionally, the cycloolefin is a C5-C12 substituted or unsubstituted monocyclic olefin, and / or a C8-C16 substituted or unsubstituted bicyclic olefin; the weight ratio of the cycloolefin to the titanium-containing catalyst is 100:(0.1-20).

[0022] Optionally, the oxidant is an oxygen-containing gas, the oxygen concentration of the oxygen-containing gas is greater than 10% by volume; and the weight ratio of oxygen in the oxygen-containing gas to the cycloolefin is greater than 1.

[0023] Through the above technical solution, the method of the present invention uses a titanium-containing catalyst to catalyze the preparation of epoxy cycloalkanes, with a high conversion rate of reactants and a high selectivity for the target product epoxy cycloalkanes.

[0024] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0025] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0026] The present invention provides a method for preparing epoxy cyclic hydrocarbons, which comprises: contacting a cycloolefin with an oxidant in the presence of a titanium-containing catalyst to carry out an oxidation reaction;

[0027] The titanium-containing catalyst is prepared by a method comprising the following steps:

[0028] (1) placing a first conductive material and a second conductive material connected to the positive electrode and the negative electrode of a DC power supply, respectively, in an electrolyte containing an inorganic acid, and electrolyzing them at a voltage of 30-100 V for 2-10 days to obtain an electrolytic mixed solution; wherein the first conductive material is a graphite rod, and the electrolytic mixed solution contains carbon dots;

[0029] (2) mixing the electrolytic mixed solution, the organic silicate and the block copolymer, and maintaining the mixture at 50-100° C. for 2-24 hours to obtain a first mixture; wherein the molecular weight of the block copolymer is 2000-100000;

[0030] (3) The first mixture, titanium source and hydrogen peroxide are mixed and maintained at 60-90° C. for 1-10 hours. The obtained second mixture is subjected to hydrothermal treatment, and the solid is taken out and dried and calcined.

[0031] In the present invention, the epoxy cyclohydrocarbon is an epoxy cycloalkane and / or an epoxy cycloalkene.

[0032] According to the present invention, there is no specific restriction on the amount of electrolyte used and it can be selected according to actual needs, for example, according to the size of the first conductive material and the second conductive material and the electrolysis conditions. In a preferred embodiment, the size of the first conductive material matches the size of the second conductive material, and the size of the first conductive material can vary within a large range. For example, the diameter of the graphite rod can be 3-20 mm and the length can be 5-50 cm, where the length refers to the axial length of the graphite rod. There is no specific restriction on the type and shape of the second conductive material and it can be any conductive material, for example, it can be iron, copper, graphite, etc., preferably graphite, and can be in the shape of a rod, a plate, etc., preferably a rod. During electrolysis, a certain distance needs to be maintained between the first conductive material and the second conductive material, for example, it can be 5-40 cm.

[0033] In one embodiment of the present invention, in step (1), the concentration of carbon dots in the electrolytic mixed solution is 10-1000 mg / L, and the concentration of the inorganic acid in the electrolyte is 5-1000 mmol / L. The inorganic acid is selected from one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, hydrobromic acid, hydroiodic acid, and sulfurous acid.

[0034] In a specific embodiment of the present invention, in step (2), the electrolytic mixed solution is divided into a first portion of the electrolytic mixed solution and a second portion of the electrolytic mixed solution; the organosilicate is mixed with the first portion of the electrolytic mixed solution to obtain a third mixture; the block copolymer is mixed with the second portion of the electrolytic mixed solution to obtain a fourth mixture; and the third mixture and the fourth mixture are mixed to obtain a first mixture. Preferably, the organosilicate is mixed with the first portion of the electrolytic mixed solution, and the block copolymer is mixed with the second portion of the electrolytic mixed solution under stirring; stirring is well known to those skilled in the art, for example, mechanical stirring can be used. The above method can be used to prepare a titanium-containing catalyst with better catalytic performance, and its use in the method for preparing epoxy cyclic hydrocarbons of the present invention can further improve the selectivity for epoxy cyclic hydrocarbons.

[0035] In a specific embodiment of the present invention, in step (2), the weight ratio of the electrolytic mixed solution, the organic silicate and the block copolymer can vary within a wide range, for example, it can be 100: (1-50): (1-40), preferably 100: (5-40): (2-30), and more preferably 100: (10-30): (5-20). Wherein, the organic silicate is well known to those skilled in the art, and may include but is not limited to tetramethyl silicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate or dimethoxydiethoxysilane, or a combination of two or three thereof. The weight average molecular weight of the block copolymer is preferably 3000-50000, and is preferably a polyethylene oxide-polypropylene oxide block copolymer, for example, it may include but is not limited to P123 and / or F127.

[0036] In a specific embodiment of the present invention, in step (3), the weight ratio of the first mixture, the titanium source, and the amount of hydrogen peroxide can vary within a wide range, for example, it can be 1000:(1-500):(1-200), preferably 1000:(5-200):(2-100), and more preferably 1000:(10-100):(5-50). The titanium source is conventionally used by those skilled in the art, and can be selected from an organic titanium source and / or an inorganic titanium source. The inorganic titanium source can include, but is not limited to, one or more of titanium chloride, titanium sulfate, and titanate. The organic titanium source can be a titanate, and can include, but is not limited to, one or more of tetrabutyl titanate and tetrapropyl titanate.

[0037] In a preferred embodiment, step (3) further comprises: mixing the first mixture, the titanium source, and a solvent, adding hydrogen peroxide to the resulting mixture, and maintaining the mixture at 0-90° C. for 1-24 hours, preferably at 10-80° C. for 2-12 hours. The solvent is water or an organic solvent such as a ketone, alcohol, acid, ester, sulfone, ether, etc., preferably water.

[0038] According to the present invention, there is no specific limitation on the method for removing the solid. For example, the solid can be removed by centrifugation or filtration. Preferably, the removed solid is washed and dried. There is no specific limitation on the solution used for washing. For example, deionized water, ethanol, etc. can be used for washing. Drying can be carried out in a vacuum drying oven. Preferably, vacuum drying is carried out at a temperature of 40-160°C and a pressure of 0-0.1 MPa for 1-24 hours.

[0039] In a preferred embodiment, in step (3), the drying is vacuum drying, and the conditions of the vacuum drying include: a temperature of 20-200°C, a pressure of 0-0.1 MPa, and a time of 1-24 hours. Calcination is an operation well known to those skilled in the art, and can be carried out in a muffle furnace or a tube furnace, for example. The present invention does not limit the calcination atmosphere, and can be, for example, an air atmosphere or an inert atmosphere. In a specific embodiment, the calcination conditions include: a temperature of 400-800°C and a time of 1-10 hours. Preferably, the calcination temperature is 450-750°C and the time is 2-8 hours.

[0040] According to the present invention, cycloolefin can be a substituted or unsubstituted monocyclic olefin of C5-C12, and / or a substituted or unsubstituted bicyclic olefin of C8-C16. Further, when cycloolefin is selected from the monocyclic olefin substituted by C5-C12 and / or the bicyclic olefin substituted by C8-C16, its substituent group can include but is not limited to halogen, methyl, ethyl, propyl group, butyl group etc. In a preferred embodiment, cycloolefin can be cyclohexene, cyclooctene, cycloheptene, dicyclopentadiene, dicyclohexene, methylcyclohexene, halogenated cyclohexene, methylcyclopentene, bromocyclohexene and chlorocyclopentene etc., preferably cyclooctene, dicyclopentadiene.

[0041] In a preferred embodiment, the catalyst is the titanium-containing catalyst of the present invention, and the weight ratio of the cycloolefin to the catalyst can be 100:(0.1-20), preferably 100:(0.5-5).

[0042] According to the present invention, the oxidation reaction can be carried out in a catalytic reactor well known to those skilled in the art, for example, in a batch reactor, a fixed bed reactor, a moving bed reactor, a suspended bed reactor or a slurry bed reactor. The amount of catalyst can be appropriately selected according to the amount of cycloolefin and oxidant, as well as the different reactors.

[0043] In one embodiment, the oxidation reaction is carried out in a slurry bed reactor. Based on 100 mL of cycloolefin, the amount of the catalyst can be 0.1-10 g, preferably 0.5-5 g, based on the titanium-containing catalyst of the present invention contained in the catalyst. In another embodiment, the oxidation reaction is carried out in a fixed bed reactor, and the weight hourly space velocity of the cycloolefin can be 0.01-10 h -1 , preferably 0.05-2h -1 .

[0044] In a specific embodiment of the present invention, the oxidation reaction conditions include: temperature of 60-200°C, pressure of 0.1-5 MPa, and time of 0.1-24 hours; preferably, temperature of 100-150°C, pressure of 0.1-2.5 MPa, and time of 1-20 hours.

[0045] According to the present invention, oxygenant is conventionally used by those skilled in the art, and for example oxygenant is oxygen-containing gas, is preferably air or oxygen, now, can carry out oxidation reaction when not adopting initiator, its effect is close with when initiator exists, can avoid adding of initiator, simplifies subsequent separation and purification process.In a specific embodiment, the oxygen concentration of oxygen-containing gas can be greater than 10 volume %.The mol ratio of oxygen in cycloolefin and oxygen-containing gas can change in a larger scope, and for example, the molar weight of oxygen in oxygen-containing gas can be 1-20 times that makes cycloolefin be oxidized to the target product oxygen demand theoretical value.In a specific embodiment, the mass ratio of oxygen in oxygen-containing gas and cycloolefin is greater than 1, is preferably (2-10): 1.

[0046] The present invention is further illustrated below by way of examples, but the present invention is not limited thereto. The reagents used in the present invention are all commercially available analytically pure reagents.

[0047] Preparation Example 1

[0048] S1, in beaker, add the aqueous solution of the sulfuric acid that the concentration of 5000mL is 120mmol / L as electrolyte, anode graphite rod (diameter 8mm length 50cm) and cathode graphite rod (diameter 8mm length 50cm) are placed wherein, keeping the distance between anode graphite rod and the cathode rod is 10cm, anode graphite rod is connected with the positive pole of DC power supply and cathode rod is connected with the negative pole of DC power supply, apply the voltage of 25V and carry out electrolysis 5 days, obtain electrolysis mixed solution; In the electrolysis mixed solution, the concentration of carbon point is 210mg / L;

[0049] S2. Divide an appropriate amount of the electrolytic mixed solution into two equal parts by volume, mix tetraethyl silicate with the first part of the electrolytic mixed solution, and stir the mixture to obtain a third mixture; mix the block copolymer P123 with the second part of the electrolytic mixed solution, and stir the mixture to obtain a fourth mixture; slowly mix the third mixture and the fourth mixture to obtain a first mixture, wherein the weight ratio of the electrolytic mixed solution, the organosilicate, and the block copolymer is 100:15:10;

[0050] S3. Under stirring, the first mixture, tetrabutyl titanate and hydrogen peroxide are mixed in a weight ratio of 1000:50:50, and maintained at 80°C for 6 hours to obtain a second mixture; the second mixture is transferred into a high-pressure reactor and sealed, and the mixture is hydrothermally treated at 150°C for 24 hours, cooled and filtered to obtain a solid, and vacuum dried at 80°C and 0.02 MPa for 6 hours, and then calcined at 500°C for 5 hours to obtain a titanium-containing catalyst A1.

[0051] Preparation Example 2

[0052] The titanium-containing catalyst A2 was prepared by the same method as in Example 1, except that in step S2, the weight ratio of the electrolytic mixed solution, the organic silicate and the block copolymer was 100:9:45.

[0053] Preparation Example 3

[0054] The titanium-containing catalyst A3 was prepared by the same method as in Example 1, except that in step S3, the weight ratio of the first mixture, tetrabutyl titanate, and hydrogen peroxide was 1000:1:110.

[0055] Preparation Example 4

[0056] The titanium-containing catalyst A4 was prepared by the same method as in Example 1, except that in step S4, the catalyst was dried and then calcined at 400° C. for 5 h.

[0057] Preparation Example 5

[0058] The titanium-containing catalyst A5 was prepared by the same method as that of Example 1, except that in step S2, the electrolytic mixed solution was not divided into two equal volumes, but the electrolytic mixed solution, tetrabutyl titanate and hydrogen peroxide were directly mixed to obtain a first mixture.

[0059] Preparation Comparative Example 1

[0060] The titanium-containing catalyst DB1 was prepared by the same method as in Preparation Example 1, except that, in step S2, the electrolytic mixed solution, hydrochloric acid and the block copolymer were mixed to obtain a first mixture.

[0061] Preparation Comparative Example 2

[0062] The titanium-containing catalyst DB2 was prepared by the same method as in Example 1, except that, in step S3, hydrogen peroxide was not used. Instead, the first mixture, tetrabutyl titanate and deionized water were mixed and maintained at 80° C. for 6 hours to obtain a second mixture.

[0063] Preparation Comparative Example 3

[0064] The titanium-containing catalyst DB3 was prepared by the same method as in Preparation Example 1, except that, in step S3, no hydrothermal treatment was performed, but the solid in the second mixture was directly collected and dried and calcined.

[0065] Preparation Comparative Example 4

[0066] The titanium-containing catalyst DB4 was prepared by the same method as that in Example 1, with the only difference being that, in step S2, an appropriate amount of the electrolytic mixed solution was divided into two equal volumes, tetraethyl silicate was mixed with the first part of the electrolytic mixed solution, and auxiliary stirring was performed during the process to obtain a third mixture; polyethylene glycol with a molecular weight equivalent to that of P123 was mixed with the second part of the electrolytic mixed solution, and auxiliary stirring was performed during the process to obtain a fourth mixture; the third mixture and the fourth mixture were slowly mixed to obtain a first mixture, wherein the weight ratio of the electrolytic mixed solution, organic silicate and polyethylene glycol was 100:15:10.

[0067] In the following examples, gas chromatography (GC: Agilent, 7890A) and gas chromatography-mass spectrometry (GC-MS: Thermo Fisher Trace ISQ) were used to analyze the oxidation products. Based on these, the following formulas were used to calculate the feed conversion rate and target product selectivity:

[0068] Cycloolefin conversion % = (molar amount of cycloolefin added before the reaction - molar amount of cycloolefin remaining after the reaction) / molar amount of cycloolefin added before the reaction × 100%;

[0069] Target product selectivity % = (molar amount of target product generated after the reaction) / molar amount of cycloolefin added before the reaction × 100%.

[0070] Example 1

[0071] 75 mg of the titanium-containing catalyst A1 prepared in the preparation example and 100 mL of cyclooctene were added to a 250 mL high-pressure reactor and sealed. Oxygen (the molar ratio of oxygen to cyclooctene was 8:1) was introduced, and the mixture was stirred at 120° C. and 2.5 MPa for 4 h. The mixture was then cooled, the pressure was released, and the catalyst was separated by centrifugation and filtration. The results of the oxidation product analysis are listed in Table 1.

[0072] Examples 2-5

[0073] Epoxycycloalkanes were prepared using the same method as in Example 1, except that the titanium-containing catalysts A2-A5 prepared in Preparation Examples 2-5 were used instead of the titanium-containing catalyst A1. The results of the oxidation product analysis are listed in Table 1.

[0074] Example 6

[0075] The same method as in Example 1 was used to prepare epoxycycloalkanes, except that the reaction temperature was 80° C., the reaction pressure was 2.0 MPa, and the reaction time was 4 h.

[0076] Comparative Examples 1-4

[0077] Epoxycycloalkanes were prepared using the same method as in Example 1, except that the titanium-containing catalyst A1 was replaced by catalysts DB1-DB4 prepared in Comparative Examples 1-4, respectively. The results of the oxidation product analysis are listed in Table 1.

[0078] Table 1

[0079]

[0080]

[0081] Example 7

[0082] 75 mg of the titanium-containing catalyst A1 prepared in Preparation Example 1 and 100 mL of dicyclopentadiene were added to a 250 mL high-pressure reactor, which was sealed. Oxygen (the molar ratio of oxygen to cycloolefin was 8:1) was introduced, and the mixture was stirred at 120° C. and 2.5 MPa for 4 h. The mixture was then cooled, the pressure was released, and the catalyst was separated by centrifugation and filtration. The results of the oxidation product analysis are listed in Table 2.

[0083] Comparative Example 5

[0084] 75 mg of the titanium-containing catalyst DB1 prepared in Preparation Comparative Example 1 and 100 mL of dicyclopentadiene were added to a 250 mL high-pressure reactor and sealed. Oxygen (the molar ratio of oxygen to cycloolefin was 8:1) was introduced, and the mixture was stirred at 120° C. and 2.5 MPa for 4 hours. The mixture was then cooled, the pressure was released, and the catalyst was separated by centrifugation and filtration. The results of the oxidation product analysis are listed in Table 2.

[0085] Table 2

[0086] Catalyst No. Conversion rate of dicyclopentadiene, % Selectivity of epoxycycloolefins, % Example 7 A1 72 89 Comparative Example 5 DB1 42 55

[0087] As can be seen from the above, the method of the present invention uses a titanium-containing catalyst prepared by a specific method. The titanium-containing catalyst has excellent reaction activity. Its use in the oxidation reaction of cycloolefins can improve the conversion rate of the raw materials and the selectivity for the target product epoxy cycloolefin.

[0088] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0089] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0090] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing epoxy cyclic hydrocarbons, the method comprising: In the presence of a titanium-containing catalyst, a cyclic olefin and an oxidant are contacted to carry out an oxidation reaction; The oxidation reaction conditions include: temperature of 60-200° C., pressure of 0.1-5 MPa, and time of 0.1-24 hours; the cycloolefin is selected from cyclohexene, cyclooctene, cycloheptene, dicyclopentadiene, dicyclohexene, methylcyclohexene, halogenated cyclohexene, methylcyclopentene, brominated cyclohexene, and chlorocyclopentene; The titanium-containing catalyst is prepared by a method comprising the following steps: (1) placing a first conductive material and a second conductive material connected to the positive electrode and the negative electrode of a DC power supply, respectively, in an electrolyte containing an inorganic acid, and electrolyzing them at a voltage of 30-100 V for 2-10 days to obtain an electrolytic mixed solution; wherein the first conductive material is a graphite rod, and the electrolytic mixed solution contains carbon dots; (2) mixing the electrolytic mixed solution, the organic silicate and the block copolymer, and maintaining the mixture at 50-100° C. for 2-24 hours to obtain a first mixture; wherein the molecular weight of the block copolymer is 2000-100000; and the weight ratio of the electrolytic mixed solution, the organic silicate and the block copolymer is 100:(1-50):(1-40); (3) Mixing the first mixture, the titanium source and the hydrogen peroxide, maintaining the mixture at 60-90°C for 1-10 hours, hydrothermally treating the obtained second mixture, removing the solid, and drying and calcining the solid; the weight ratio of the first mixture, the titanium source and the hydrogen peroxide is 100: (5-200): (2-100).

2. The method according to claim 1, wherein In step (1), the concentration of carbon dots in the electrolytic mixed solution is 10-1000 mg / L, and the concentration of inorganic acid in the electrolyte is 5-1000 mmol / L.

3. The method according to claim 1, wherein In step (2), the electrolytic mixed solution is divided into a first part of the electrolytic mixed solution and a second part of the electrolytic mixed solution; The organosilicate is mixed with the first part of the electrolytic mixed solution to obtain a third mixture, the block copolymer is mixed with the second part of the electrolytic mixed solution to obtain a fourth mixture, and the third mixture and the fourth mixture are mixed to obtain a first mixture.

4. The method according to claim 1, wherein In step (3), the drying is vacuum drying, and the conditions for the vacuum drying include: temperature of 20-200°C, pressure of 0-0.1 MPa, and time of 1-24 hours; the conditions for the roasting include: temperature of 400-800°C, and time of 1-10 hours.

5. The method according to claim 1, wherein The inorganic acid is selected from one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, hydrobromic acid, hydroiodic acid and sulfurous acid; The organosilicate is selected from tetramethyl silicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate or dimethoxydiethoxysilane, or a combination of two or three thereof; The titanium source is selected from one or more of titanium chloride, titanium sulfate, titanate, tetrabutyl titanate and tetrapropyl titanate; The block copolymer is a polyethylene oxide-polypropylene oxide block copolymer.

6. The method according to claim 5, wherein: The block copolymer is P123 and / or F127.

7. The method according to claim 1, wherein The weight ratio of the cycloolefin to the titanium-containing catalyst is 100:(0.1-20).

8. The method according to claim 1, wherein The oxidant is an oxygen-containing gas, the oxygen concentration of the oxygen-containing gas is greater than 10% by volume; the weight ratio of oxygen in the oxygen-containing gas to the cycloolefin is greater than 1.

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