阅读说明：本技术 一种改性氧化催化材料及其制备方法和应用 (Modified oxidation catalytic material and preparation method and application thereof ) 是由 史春风 康振辉 刘阳 黄慧 王肖 于 2020-03-31 设计创作，主要内容包括：本发明涉及一种改性氧化催化材料及其制备方法和应用,该方法包括：将第一导电物和第二导电物分别与直流电源的正极和负极连接后置于电解液中,在5-50V的电压下电解0.5-10天,得到碱性碳点溶液；其中,第一导电物为石墨棒,电解液含有有机碱；碱性碳点溶液与氧化催化材料混合,得到混合物；在耐热密闭容器内,使混合物在85-300℃的条件下进行水热反应5-300小时,收集固体产物,可选地焙烧。本发明的方法制得的改性氧化催化材料的反应活性中心多,具有较优的反应活性和目的产物选择性。(The invention relates to a modified oxidation catalytic material, a preparation method and application thereof, wherein the method comprises the following steps: respectively connecting the first conductive substance and the second conductive substance with the anode and the cathode of a direct current power supply, placing the two conductive substances into an electrolyte, and electrolyzing for 0.5-10 days under the voltage of 5-50V to obtain an alkaline carbon dot solution; wherein the first conductor is a graphite rod, and the electrolyte contains organic alkali; mixing the alkaline carbon dot solution with an oxidation catalytic material to obtain a mixture; and (3) carrying out hydrothermal reaction on the mixture at 85-300 ℃ for 5-300 hours in a heat-resistant closed container, collecting a solid product, and optionally roasting. The modified oxidation catalytic material prepared by the method has more reaction active centers, and has better reaction activity and target product selectivity.)

1. A method of modifying an oxidation catalyst material, the method comprising:

(1) respectively connecting the first conductive substance and the second conductive substance with the anode and the cathode of a direct current power supply, placing the two conductive substances into an electrolyte, and electrolyzing for 0.5-10 days under the voltage of 5-50V to obtain an alkaline carbon dot solution; wherein the first conductor is a graphite rod, and the electrolyte contains organic alkali;

(2) mixing the alkaline carbon dot solution with an oxidation catalytic material to obtain a mixture;

(3) and carrying out hydrothermal reaction on the mixture at 85-300 ℃ for 5-300 hours in a heat-resistant closed container, collecting a solid product, and optionally roasting.

2. The method according to claim 1, wherein in the step (1), the electrolyte further contains high purity water, and the weight ratio of the high purity water to the amount of the organic base is 100: (0.01-20).

3. The method according to claim 1, wherein in the step (1), the basic carbon dot solution has a carbon dot concentration of 0.01-2 mg/L; the weight ratio of the organic base to the carbon dots in the alkaline carbon dot solution is (10-500): 1.

4. the method of claim 1, wherein in step (2), the weight ratio of the amount of the oxidation catalyst material to the basic carbon dot solution is 1: (1-1000).

5. The method of claim 1, wherein the conditions of the hydrothermal reaction comprise: the treatment is carried out at 120-250 ℃ and autogenous pressure for 1-96 hours.

6. The method of claim 1, wherein the organic base is urea, a quaternary ammonium base compound, a fatty amine compound, or an alcohol amine compound, or a combination of two or three thereof.

7. The method of claim 6, wherein the quaternary ammonium base compound is tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide, or a combination of two or three thereof;

the aliphatic amine compound is ethylamine, n-butylamine, butanediamine or hexanediamine, or a combination of two or three of the ethylamine, the n-butylamine, the butanediamine and the hexanediamine;

the alcohol amine compound is monoethanolamine, diethanolamine or triethanolamine, or a combination of two or three of the monoethanolamine, diethanolamine and triethanolamine.

8. The method of claim 1, wherein the oxidative catalytic material is a titanium-containing molecular sieve, an iron-containing molecular sieve, a vanadium-containing molecular sieve, or a tin-containing molecular sieve, or a combination of two or three thereof.

9. The process of claim 1, wherein the graphite rod is 2-20mm in diameter and 2-100cm in length; the second conductive object is an iron rod, an iron plate, a graphite rod, a graphite plate, a copper plate or a copper rod.

10. A modified oxidative catalytic material prepared by the method of any one of claims 1 to 9.

11. Use of the modified oxidative catalytic material of claim 10 in the catalytic oxidation of olefins.

Technical Field

The invention relates to a modified oxidation catalytic material, a preparation method and application thereof.

Background

The carbon nano material is fine carbon particles with the size of nano-scale (1-100 nm), is similar to common nano materials, and also has special properties such as quantum size effect, small size effect, macroscopic quantum tunneling effect and the like in the aspects of optics, electricity, magnetism and the like. The fine carbon nano-particles with the size less than 10nm discovered when the single-layer carbon nano-tube is purified by an electrophoresis method are firstly named as carbon quantum dots (carbon dots for short) and are a novel small-size carbon nano-material. Carbon quantum dots are also referred to as fluorescent carbon quantum dots (FCDs) because of their excellent fluorescent properties. From their discovery to the short years of utilization, FCDs have become a new star of the carbon nanofamily. In recent years, the properties and utilization of FCDs in all aspects have been studied more and more carefully and comprehensively, and finally, significant progress has been made. Therefore, much attention has been paid to the study of the properties and utilization of FCDs. Researchers design a series of high-activity composite catalytic materials based on FCDs, which not only enhances the light absorption of the composite materials, but also effectively improves the catalytic efficiency of the reaction.

In the oxidation reaction of organic matters, oxidation catalysis materials such as heteroatom molecular sieves (titanium silicalite molecular sieves) can adopt pollution-free low-concentration hydrogen peroxide as an oxidant, can catalyze various organic oxidation reactions such as olefin epoxidation, alkane partial oxidation, alcohol oxidation, phenol hydroxylation and the like, avoids the problems of complex oxidation process and environmental pollution, has the advantages of incomparable energy conservation, economy, environmental friendliness and the like of a traditional oxidation system, and has good reaction selectivity, so that the titanium silicalite molecular sieves have great industrial utilization prospects. But the repeatability, stability, cost and the like of the existing synthesis method of the oxidation catalytic material are not ideal. Therefore, the development of the oxidation catalyst material is key to the improvement of the corresponding synthesis method. The modified oxidation catalytic material combined with the characteristics of FCDs is a worthy-to-be-explored modification route of oxidation catalytic materials.

Disclosure of Invention

The invention aims to provide a modified oxidation catalytic material, a preparation method and application thereof.

In order to achieve the above object, a first aspect of the present invention provides a method for modifying an oxidation catalyst material, the method comprising:

(1) respectively connecting the first conductive substance and the second conductive substance with the anode and the cathode of a direct current power supply, placing the two conductive substances into an electrolyte, and electrolyzing for 0.5-10 days under the voltage of 5-50V to obtain an alkaline carbon dot solution; wherein the first conductor is a graphite rod, and the electrolyte contains organic alkali;

(2) mixing the alkaline carbon dot solution with an oxidation catalytic material to obtain a mixture;

(3) and carrying out hydrothermal reaction on the mixture at 85-300 ℃ for 5-300 hours in a heat-resistant closed container, collecting a solid product, and optionally roasting.

Optionally, in the step (1), the electrolyte further contains high-purity water, and the weight ratio of the high-purity water to the organic base is 100: (0.01-20).

Optionally, in the step (1), the carbon dot concentration of the alkaline carbon dot solution is 0.01-2 mg/L; the weight ratio of the organic base to the carbon dots in the alkaline carbon dot solution is (10-500): 1.

optionally, in the step (2), the weight ratio of the oxidation catalyst material to the alkaline carbon dot solution is 1: (1-1000).

Optionally, the hydrothermal reaction conditions include: the treatment is carried out at 120-250 ℃ and autogenous pressure for 1-96 hours.

Optionally, the organic base is urea, a quaternary ammonium base compound, a fatty amine compound, or an alcohol amine compound, or a combination of two or three thereof.

Optionally, the quaternary ammonium base compound is tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide, or a combination of two or three thereof;

the aliphatic amine compound is ethylamine, n-butylamine, butanediamine or hexanediamine, or a combination of two or three of the ethylamine, the n-butylamine, the butanediamine and the hexanediamine;

the alcohol amine compound is monoethanolamine, diethanolamine or triethanolamine, or a combination of two or three of the monoethanolamine, diethanolamine and triethanolamine.

Optionally, the oxidation catalytic material is a titanium-containing molecular sieve, an iron-containing molecular sieve, a vanadium-containing molecular sieve, or a tin-containing molecular sieve, or a combination of two or three thereof.

Optionally, the graphite rod has a diameter of 2-20mm and a length of 2-100 cm; the second conductive object is an iron rod, an iron plate, a graphite rod, a graphite plate, a copper plate or a copper rod.

In a second aspect, the present invention provides a modified oxidative catalytic material prepared by the method of the first aspect of the present invention.

In a third aspect, the present invention provides a modified oxidation catalyst material provided in the second aspect of the present invention for use in the catalytic oxidation of an olefin.

Through the technical scheme, the method can increase the number of the reaction active centers of the oxidation catalytic material, so that the modified oxidation catalytic material has better reaction activity, selectivity of a target product and activity stability.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

In a first aspect, the present invention provides a method for modifying an oxidation catalyst material, the method comprising:

(1) respectively connecting the first conductive substance and the second conductive substance with the anode and the cathode of a direct current power supply, placing the two conductive substances into an electrolyte, and electrolyzing for 0.5-10 days under the voltage of 5-50V to obtain an alkaline carbon dot solution; wherein the first conductor is a graphite rod, and the electrolyte contains organic alkali;

(2) mixing the alkaline carbon dot solution with an oxidation catalytic material to obtain a mixture;

(3) and carrying out hydrothermal reaction on the mixture at 85-300 ℃ for 5-300 hours in a heat-resistant closed container, collecting a solid product, and optionally roasting.

The method can lead the oxidation catalysis material to generate holes or defects in the treatment process in the presence of the alkaline carbon dot solution, on one hand, the quantity of the reaction active centers of the oxidation catalysis material can be increased, and on the other hand, the diffusion speed of reactants and products can be increased, thereby being beneficial to improving the reaction activity and activity stability of the oxidation catalysis material and the selectivity of target products.

In one specific embodiment, in the step (1), the first conductive material and the second conductive material are respectively connected with the positive electrode and the negative electrode of the direct current power supply, then are placed in the electrolyte, and are electrolyzed under the voltage of 2-35V for 1-5 days to obtain the alkaline carbon dot solution.

According to the present invention, preferably, the collected solid product is calcined in step (3). Further preferably, the collected solid product is washed, dried and then calcined, and the solution used for washing is not particularly limited, and may be, for example, deionized water. Wherein drying and calcination are well known to those skilled in the art, such as drying in a constant temperature drying oven or under natural conditions, calcination in a tube furnace or a muffle furnace, and drying and calcination temperatures and times, respectively, can vary within wide ranges, and in one embodiment, the calcination temperature is 500-.

According to the invention, in step (1), the electrolyte may also contain high purity water, and the weight ratio of the amounts of high purity water and organic base may vary within a wide range, and may be, for example, 100: (0.01-20), preferably 100: (0.1-10). The high purity water is water with conductivity less than 0.1 mus/cm and residual salt content less than 0.3mg/L at 25 deg.C, and has no non-dielectric trace bacteria, microbes, particles, etc. impurities removed. The amount of the electrolyte is not particularly limited, and may be adjusted according to the material and size of the conductive material and the electrolysis conditions.

According to the present invention, in the step (1), the carbon dot concentration of the alkaline carbon dot solution may be 0.01 to 2 mg/L; the weight ratio of the content of the organic base to the content of the carbon dots in the basic carbon dot solution may be (10-500): 1. preferably, the carbon dot concentration of the alkaline carbon dot solution is 0.02-1 mg/L; the weight ratio of the organic alkali to the carbon dots in the alkaline carbon dot solution is (20-200): 1.

in one embodiment, step (1) may comprise: and concentrating the alkaline carbon dot solution. The concentration treatment is a technique conventionally adopted by those skilled in the art, such as membrane separation concentration, etc., and the present invention is not described herein again. The concentration of the basic carbon dot solution obtained by the concentration treatment may be 0.05 to 2mg/mL, and in a preferred embodiment, the concentration of the carbon dot solution obtained by the concentration treatment is 0.1 to 1 mg/mL.

According to the present invention, in the step (2), the manner of mixing the alkaline carbon dot solution and the oxidation catalyst material is not limited as long as the alkaline carbon dot solution and the oxidation catalyst material can be uniformly mixed, and for example, the alkaline carbon dot solution and the oxidation catalyst material can be placed in a beaker and stirred to be mixed. The weight ratio of the dosage of the oxidation catalytic material to the dosage of the alkaline carbon dot solution is 1: (1-1000), preferably 1: (5-100). Among them, oxidation catalytic materials are well known to those skilled in the art, i.e., catalytic materials in oxidation reactions can be applied, and the oxidation catalytic materials can be, but are not limited to, titanium-containing molecular sieves, iron-containing molecular sieves, vanadium-containing molecular sieves, and tin-containing molecular sieves.

According to the present invention, the hydrothermal reaction is well known to those skilled in the art, and the hydrothermal reaction may be carried out in a heat-resistant closed vessel, for example, an autoclave. The pressure of the hydrothermal reaction is not particularly limited, and may be the autogenous pressure of the system, or may be under an additional applied pressure condition, and preferably, the hydrothermal reaction process is performed under the autogenous pressure (generally, in a closed vessel). In one embodiment, the conditions of the hydrothermal reaction may include: the treatment is carried out at 120-250 ℃ and autogenous pressure for 1-96 hours. Preferably, the hydrothermal treatment is carried out at 140 ℃ and 200 ℃ and autogenous pressure for 2 to 48 hours. The method of collecting the solid product after the hydrothermal reaction may employ a method conventionally employed by those skilled in the art, such as filtration, centrifugation and the like.

According to the invention, the organic base may be urea, a quaternary ammonium base compound, a fatty amine compound or an alcohol amine compound, or a combination of two or three of them.

According to the invention, the quaternary ammonium base compound has the general formula (R)¹)₄NOH, wherein R¹May be at least one of a straight chain alkyl group having 1 to 4 carbon atoms and a branched alkyl group having 3 to 4 carbon atoms, for example, R¹Can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl or methallyl, and is preferably n-propyl, i.e. the quaternary ammonium compound is tetrapropyl quaternary ammonium. In one embodiment, the quaternary ammonium base compound is tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide, or a combination of two or three thereof.

According to the invention, the aliphatic amine compound has the general formula R²(NH₂)_nWherein R is²It may be an alkyl group having 1 to 6 carbon atoms or an alkylene group having 1 to 6 carbon atoms, such as a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group, a n-hexyl group, a methylene group, an ethylene group, a n-propylene group, a n-butylene group or a n-hexylene group, and n is an integer of 1 or 2. Preferably, the aliphatic amine compound is ethylamine, n-butylamine, butanediamine or hexanediamine, or a combination of two or three thereof. In one embodiment, the aliphatic amine compound is ethylamine, n-butylamine, butanediamine, or hexamethylenediamine, or a combination of two or three thereof.

According to the invention, the alkanolamines have the general formula (HOR)³)_mNH_(3-m)Wherein R is³May be one having 1 to 4 carbon atomsAt least one of an alkyl group and an alkylene group having 3 to 4 carbon atoms, and m is 1, 2 or 3. In one embodiment, the alkanolamine compound is monoethanolamine, diethanolamine or triethanolamine, or a combination of two or three thereof.

According to the invention, the diameter of the graphite rod is 2-20mm, and the length is 2-100 cm; the second conductive material may be any of various materials capable of conducting electricity, and has no material or shape requirement, and may be a rod or a plate having a shape common to the materials, specifically, an iron rod, an iron plate, a graphite rod, a graphite plate, a copper rod, or the like. The size of the second conductor is also not particularly limited, and a graphite rod matching the size of the first conductor is most preferable. The first conductor and the second conductor may be kept at a distance, for example 3-10cm, during the electrolysis.

In a second aspect, the present invention provides a modified oxidative catalytic material prepared by the method of the first aspect of the present invention.

In a third aspect, the present invention provides a modified oxidation catalyst material provided in the second aspect of the present invention for use in the catalytic oxidation of an olefin. The method of the invention can improve the conversion rate of raw materials and improve the selectivity of target products.

In one embodiment, the present invention provides the use of a modified oxidation catalytic material in the catalytic oxidation of an olefin to an olefin oxide.

The invention is further illustrated by the following examples, but is not to be construed as being limited thereto.

The reagents used in the examples and comparative examples were all commercially available analytical grade reagents. The oxidation catalyst material used was a titanium-containing molecular sieve, designated CAT-1, synthesized according to the prior art (methods disclosed in Thangaraj A, Eapen M J, Sivasan ker S, et al. students on the synthesis of titanium silicalite, TS-1[ J ]. Zeolite, 1992,12(8): 943-.

The oxidation catalytic material used in example 7 was a titanium-containing molecular sieve synthesized according to the prior art (prepared according to the method described in example 1 of chinese patent application 96106315.7), designated as CAT-2. In examples and comparative examples, the mesoporous specific surface area and the total specific surface area were measured by a nitrogen adsorption capacity method, and calculated according to the BJH calculation method (see petrochemical analysis method (RIPP test method), RIPP151-90, scientific Press, 1990).

Example 1

(1) Adding 800mL of ultrapure water and tetrapropylammonium hydroxide (the weight ratio of the amount of the high-purity water to the tetrapropylammonium hydroxide is 100: 2.04) serving as electrolyte into a 1000mL beaker at normal temperature and normal pressure, placing an anode graphite rod (with the diameter of 8mm and the length of 50cm) and a cathode graphite rod (with the diameter of 8mm and the length of 50cm) in the beaker, keeping the distance between the anode graphite rod and the cathode graphite rod at 8cm, connecting the anode graphite rod with the positive pole of a direct-current power supply, connecting the cathode rod with the negative pole of the direct-current power supply, applying a voltage of 15V to electrolyze for 4 days, and concentrating after the electrolysis is finished to obtain an alkaline carbon dot solution; wherein the carbon concentration of the alkaline carbon dot solution is 0.1mg/mL, and the weight ratio of the tetrapropylammonium hydroxide to the carbon dot content in the alkaline carbon dot solution is 25: 1;

(2) adding an oxidation catalytic material CAT-1 into an alkaline carbon dot solution containing tetrapropylammonium hydroxide, and uniformly stirring and mixing to obtain a mixture; wherein the weight ratio of the dosage of the oxidation catalytic material to the dosage of the alkaline carbon dot solution is 1: 6;

(3) and (3) placing the mixture in a sealed high-pressure reaction kettle, carrying out hydrothermal treatment at the temperature of 150 ℃ and the autogenous pressure for 48 hours, filtering the obtained substance, washing the obtained substance with water, naturally drying the obtained substance, and roasting the obtained product at the temperature of 550 ℃ for 3 hours to obtain the modified oxidation catalytic material A1.

Example 2

An oxidation catalyst material was modified in the same manner as in example 1 to obtain a modified oxidation catalyst material a2, except that in step (1), the amount of high purity water and tetrapropylammonium hydroxide was changed to 100: 23. in the obtained alkaline carbon point solution, the carbon point concentration is 0.15mg/mL, and the weight ratio of the tetrapropylammonium hydroxide to the carbon point content is 260: 1.

example 3

An oxidation catalyst material was modified in the same manner as in example 1 to obtain a modified oxidation catalyst material a3, except that in step (1), the amount of high purity water and tetrapropylammonium hydroxide was changed to 100: 0.007. in the obtained alkaline carbon point solution, the carbon point concentration is 0.08mg/mL, and the weight ratio of the tetrapropylammonium hydroxide to the carbon point content is 3: 1.

example 4

The oxidation catalyst material was modified in the same manner as in example 1 to obtain a modified oxidation catalyst material a4, except that in step (2), the amount of the oxidation catalyst material to the basic carbon dot solution was changed in the weight ratio of 1: 0.6.

example 5

The oxidation catalyst material was modified in the same manner as in example 1 to obtain a modified oxidation catalyst material a5, except that in step (2), the amount of the oxidation catalyst material to the basic carbon dot solution was changed in the weight ratio of 1: 1020.

example 6

The oxidation catalyst material was modified in the same manner as in example 1 to obtain a modified oxidation catalyst material A6, except that in step (3), hydrothermal treatment was carried out at a temperature of 500 ℃ and an autogenous pressure for 48 hours.

Example 7

(1) Adding 800mL of ultrapure water and triethanolamine (the weight ratio of the amount of the high-purity water to the amount of the triethanolamine is 100: 12) into a 1000mL beaker as electrolyte, placing an anode graphite rod (with the diameter of 8mm and the length of 50cm) and a cathode graphite rod (with the diameter of 8mm and the length of 50cm) into the beaker, keeping the distance between the anode graphite rod and the cathode graphite rod at 10cm, connecting the anode graphite rod with the positive electrode of a direct current power supply, connecting the cathode graphite rod with the negative electrode of the direct current power supply, applying 40V voltage to electrolyze for 3 days, and concentrating after the electrolysis is finished to obtain an alkaline carbon dot solution; wherein the carbon dot concentration of the alkaline carbon dot solution is 0.2mg/mL, and the weight ratio of the tetrapropylammonium hydroxide to the carbon dot content in the alkaline carbon dot solution is 76: 1;

(2) adding an oxidation catalytic material CAT-2 into an alkaline carbon dot solution containing triethanolamine, and uniformly stirring and mixing to obtain a mixture; wherein the weight ratio of the dosage of the oxidation catalytic material to the dosage of the alkaline carbon dot solution is 1: 100, respectively;

(3) placing the mixture in a sealed high-pressure reaction kettle, carrying out hydrothermal treatment for 72 hours at the temperature of 180 ℃ and the autogenous pressure, filtering the obtained product, washing the obtained product with water, naturally drying the product, and roasting the product for 4 hours at the temperature of 600 ℃ to obtain the modified oxidation catalytic material A7.

Comparative example 1

(1) Adding 800mL of ultrapure water serving as electrolyte into a 1000mL beaker at normal temperature and normal pressure, placing an anode graphite rod (with the diameter of 8mm and the length of 50cm) and a cathode graphite rod (with the diameter of 8mm and the length of 50cm) in the beaker, keeping the distance between the anode graphite rod and the cathode graphite rod at 8cm, connecting the anode graphite rod with the positive electrode of a direct current power supply, connecting the cathode graphite rod with the negative electrode of the direct current power supply, and applying a voltage of 15V to electrolyze for 4 days to obtain a carbon dot solution; the carbon dot concentration of the carbon dot solution is 0.08 mg/mL;

(2) adding an oxidation catalyst into the carbon dot solution, and uniformly stirring and mixing to obtain a mixture; wherein the weight ratio of the dosage of the oxidation catalytic material to the dosage of the carbon dot solution is 1: 6;

(3) and (3) placing the mixture in a sealed high-pressure reaction kettle, carrying out hydrothermal treatment at the temperature of 150 ℃ and the autogenous pressure for 48 hours, filtering the obtained substance, washing the obtained substance with water, naturally drying the obtained substance, and roasting the obtained substance at the temperature of 550 ℃ for 3 hours to obtain the modified oxidation catalytic material DA 1.

Comparative example 2

Adding the oxidation catalyst into tetrapropylammonium hydroxide solution, stirring and mixing uniformly, placing the obtained mixture into a sealed high-pressure reaction kettle, carrying out hydrothermal treatment for 48 hours at the temperature of 150 ℃ and under autogenous pressure, filtering the obtained product, washing the product with water, drying the product naturally, and roasting the product for 3 hours at the temperature of 550 ℃ to obtain the modified oxidation catalyst DA 2.

Wherein the content of tetrapropylammonium hydroxide in the tetrapropylammonium hydroxide solution is the same as that of tetrapropylammonium hydroxide in the basic carbon point solution in example 1, and the amount of the tetrapropylammonium hydroxide solution is the same as that of the basic carbon point solution.

Test example

The unmodified oxidation catalyst material CAT, and the modified oxidation catalyst materials prepared in examples 1 to 7 and comparative examples 1 to 2 were used as catalysts for the catalytic oxidation reaction of propylene.

Oxidizing catalytic material (modified or unmodified), solvent methanol, and hydrogen peroxide aqueous solution (H in hydrogen peroxide aqueous solution)₂O₂Content of 27.5 wt.%) according to the oxidation catalyst material: methanol: hydrogen peroxide ═ 4: 150: 25 in a weight ratio of the propylene to the propylene, controlling the reaction temperature to be 40 ℃, and stirring the mixture according to the weight ratio of the propylene: hydrogen peroxide ═ 1.5: 1 molar ratio, start timing and react at this temperature for 1 hour.

The product distribution of the reaction product was determined by a Varian 3400 gas chromatograph with FFAP as a capillary column (30 m.times.0.25 mm), and the conditions of the gas chromatograph: nitrogen carrier gas, temperature programmed: 60 ℃,1 minute, 15 ℃/minute, 180 ℃, 15 minutes; split ratio, 10: 1; the injection port temperature is 300 ℃; detector temperature, 300 ℃. The test results are shown in Table 1.

The following formulas were used to calculate the feedstock conversion and target product selectivity:

hydrogen peroxide conversion (molar amount of hydrogen peroxide added before the reaction-molar amount of hydrogen peroxide remaining after the reaction)/molar amount of hydrogen peroxide added before the reaction x 100%,

the propylene oxide selectivity is the molar amount of propylene oxide produced by the reaction/(the molar amount of propylene added before the reaction-the molar amount of propylene remaining after the reaction) × 100%.

TABLE 1

As can be seen from table 1, the modified oxidation catalyst material prepared by the method of the present invention has a high ratio of mesopore volume to total pore volume (mesopore volume ratio for short), and a large ratio of mesopore volume ratio to mesopore specific surface area ratio indicates that the mesopore porosity is large, and when the modified oxidation catalyst material is used for the catalytic oxidation of olefin, the conversion rate of the oxidant is high, and the selectivity of the target product is high.

As is clear from comparison between example 1 and examples 2 to 3, the electrolyte solution in step (1) preferably contains the high purity water and the organic base in an amount of 100: (0.01-20), the modified oxidation catalytic material with better catalytic performance can be prepared, and when the modified oxidation catalytic material is used for the process of preparing the olefin oxide such as propylene oxide by catalytic oxidation of the olefin, the conversion rate of an oxidant is higher, and the selectivity of the target product olefin oxide is higher; as can be seen from comparison between example 1 and examples 4 to 5, the amount of the oxidation catalyst material and the basic carbon dot solution used in step (2) is preferably in a weight ratio of 1: (1-1000), the modified oxidation catalytic material with better catalytic performance can be prepared, and when the modified oxidation catalytic material is used in the process of preparing the olefin oxide such as propylene oxide by catalytic oxidation of olefin, the conversion rate of an oxidant is higher, and the selectivity of the target product olefin oxide is higher; as can be seen from comparison between example 1 and example 6, the hydrothermal reaction conditions including treatment at 120-250 ℃ and autogenous pressure for 1-96 hours can be used to prepare modified oxidation catalyst material with better catalytic performance, and when the modified oxidation catalyst material is used in the process of preparing olefin oxide by olefin catalytic oxidation, the conversion rate of oxidant is higher and the selectivity of the target product olefin oxide is higher.

The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.