A TS-1 zeolite catalyst continuously modified by alkali, silanization and two metal oxides, and its preparation method and application

Abstract

The present invention relates to the field of chemical industry and pharmaceuticals, and in particular to a TS-1 zeolite catalyst modified continuously by alkali, silanization and two kinds of metal oxides and its application. The method comprises the following steps: TS-1 zeolite is subjected to alkali treatment, and then silanization, and then modified with two kinds of metal oxides, or TS-1 zeolite is subjected to alkali treatment, and then silanization is carried out after it is modified with two kinds of metal oxides, and then the required catalyst is obtained by drying and roasting. The catalyst prepared by the present invention has high activity (conversion rate is higher than 80%), good selectivity of target product (total selectivity of product is higher than 90%), and the advantages such as catalyst is easy to reuse and regenerate in the reaction of ethylbenzene oxidation to prepare acetophenone and phenylethyl alcohol high value-added products, and can significantly reduce the energy consumption of product separation. The catalyst preparation of the present invention is simple, green and environmentally friendly and easy to separate and recycle, and the reaction temperature is low, with broad application prospects.

Description

Technical Field

[0001] The present invention relates to the fields of chemistry, chemical engineering and pharmacy, and in particular to a TS-1 zeolite catalyst continuously modified by alkali, silanization and two metal oxides and application thereof. Background Art

[0002] Acetophenone and phenylethanol are important organic synthesis intermediates, and their global consumption is increasing. Acetophenone is a key intermediate in the manufacture of various resins, pharmaceuticals, and perfumes. Both 1-phenylethanol and 2-phenylethanol are widely used in pharmaceuticals, cosmetics, food, dyes, and fragrances. Acetophenone is synthesized via several methods, including the decomposition of cumene peroxide, the Hock method, and the Friedel-Crafts acylation reaction using homogeneous catalysts, solvents, and oxidants. Phenylethanol is isolated as a by-product. These methods generate large amounts of highly toxic and corrosive waste, limiting their application. However, these techniques can lead to environmental concerns and compromise acetophenone production. The selective oxidation of alkyl C-H bonds in ethylbenzene to produce the high-value-added product acetophenone is a fundamental organic chemistry reaction in both basic research and the chemical industry. As important fine chemical intermediates, both acetophenone and phenylethanol are more valuable than ethylbenzene. Therefore, research on green synthesis of acetophenone and phenylethanol from inexpensive raw materials (ethylbenzene and H2O2) is of great social significance.

[0003] Ethylbenzene oxidation is a promising method for synthesizing acetophenone using heterogeneous catalysts in liquid and gas phase reactions, playing a crucial role in the selective production of acetophenone and phenylethanol. Currently, industrial production of acetophenone involves liquid-phase oxidation of ethylbenzene in acetic acid using homogeneous cobalt-based compounds as catalysts. However, the corrosive nature of the solvent and the self-aggregation of the catalyst's active sites deactivate the catalyst, making separation difficult. Therefore, environmentally friendly and practical routes to acetophenone from ethylbenzene using molecular oxygen, H₂O₂, or tert-butyl hydroperoxide have become a goal of the pursuit of "green chemistry."

[0004] Xu Jie et al., in patent publication number CN 114192178 A, entitled "Preparation and Application of a Cobalt-Containing Carbon Nitride Catalyst," disclosed a catalyst for the oxidation of ethylbenzene to acetophenone, achieving an acetophenone selectivity exceeding 87% and a yield exceeding 40%. However, the reaction was conducted under intermittent corrosion and medium-high pressure (0.5 MPa). Furthermore, the catalytic material, a fine, porous carbon powder, was difficult to separate. Furthermore, the catalyst was relatively expensive, and the reaction temperature and time were relatively high.

[0005] Liu et al. published an article titled “Manganese-containing hollow TS-1: Description of the catalytic sites and surface properties for solvent-free oxidation of ethylbenzene” in the journal Chemical Engineering Journal, 2016, 313: 1382-1395, reporting a method for preparing hollow MnO by dissolution-recrystallization-impregnation. x / TS-1 catalyst, which is effectively used for the oxidation of ethylbenzene to acetophenone, with an ethylbenzene conversion rate of 37.1% and an acetophenone selectivity of 68.6%. However, the reaction has a low ethylbenzene conversion rate and low selectivity, a complex and time-consuming catalyst preparation procedure, and a high system pressure.

[0006] N.K. Mal and A.V. Ramaswamy published an article titled “Oxidation of ethylbenzene over Ti-, V-, and Sn-containing silicates with MFI structure” in the journal Applied Catalysis A: General, 1996, 143, (1) 75–85. They reported the oxidation of ethylbenzene over TS-1, VS-1, and Sn-silicalite-1 (MFI structure) at 60–80°C using H₂O₂ as the oxidant. The main products were 1-phenylethanol and acetophenone produced by side chain oxidation. The conversion of ethylbenzene was approximately 20%, and the overall selectivity for 1-phenylethanol and acetophenone was 70–80%. The problems with this process were the low conversion of ethylbenzene and the low overall selectivity for the desired products, which increased the energy consumption for subsequent separation and reduced the added value of the products. Summary of the Invention

[0007] The purpose of the present invention is to solve the above-mentioned technical problems existing in the prior art and to provide a TS-1 zeolite catalyst continuously modified by alkali, silanization and two metal oxides, thereby obtaining an environmentally friendly, highly active and easily separable catalyst for catalytic ethylbenzene oxidation.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows:

[0009] In one aspect, the present invention provides a method for preparing a TS-1 zeolite catalyst modified by alkali, silanization, and two metal oxides, the method comprising the following steps:

[0010] a. TS-1 zeolite was subjected to base modification treatment with an alkali to obtain a base-modified TS-1 zeolite, designated as TS-1-X;

[0011] b. The TS-1-X obtained in step a is modified by one of the following two methods:

[0012] Method 1: TS-1-X obtained in step a is subjected to silanization modification treatment with an alkane solution of orthosilicate to obtain a silanized TS-1 zeolite, recorded as TS-1-X@SiO2, and then the first metal oxide and the second metal oxide are loaded on TS-1-X@SiO2 as a carrier, and the catalyst is obtained by filtering, washing, drying and calcining.

[0013] Method 2: TS-1-X obtained in step a is used as a carrier to load the first metal oxide and the second metal oxide, and the catalyst loaded with the two metal oxides is obtained by filtering, washing, filtering, drying and calcining, and recorded as M1-M2 / TS-1-X. Subsequently, M1-M2 / TS-1-X is subjected to silanization modification treatment with an alkane solution of orthosilicate, and dried and calcined to obtain the catalyst.

[0014] In the above technical solution, further, in step a, the alkali modification treatment method is: adding TS-1 zeolite to an alkaline solution under normal temperature, normal pressure and stirring conditions, reacting at a constant temperature of 100-220°C for 6-36 hours, drying at 80-150°C after the reaction, and then calcining at 400-650°C in air for 4-48 hours to obtain TS-1-X;

[0015] The concentration of the alkaline solution is 0.1-2.0 mol / L;

[0016] The ratio of the alkaline solution to the TS-1 zeolite is 1g:0.04-1.2g;

[0017] The base is an organic base or an inorganic base. The organic base is at least one of tetrapropylammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetraisopropylammonium hydroxide, tetraisobutylammonium hydroxide, and tetrabutylammonium hydroxide. The inorganic base is at least one of sodium hydroxide, potassium hydroxide, and ammonia water.

[0018] In the above technical solution, further, in the method 1, the method for silanization modification of TS-1-X is: immersing TS-1-X in an alkane solution with a mass fraction of 2%-40% orthosilicate for 6-48 hours, heating and refluxing at 80-150°C to evaporate the alkane, and calcining in air at 400-650°C for 4-48 hours;

[0019] The mass ratio of the alkane solution of orthosilicate to TS-1-X is 5-50:1, and m(SiO2):m(TS-1-X)=1.0-40.0:100.

[0020] In the above technical solution, further, in the second method, the method for silanization modification of M1-M2 / TS-1-X is: immersing M1-M2 / TS-1-X in an alkane solution of orthosilicate with a mass fraction of 2%-40% for 6-48 hours, heating and refluxing at 80-150°C until the alkane is evaporated, and calcining in air at 400-650°C for 4-48 hours;

[0021] The mass ratio of the alkane solution of orthosilicate to M1-M2 / TS-1-X is 5-50:1, and m(SiO2):m(M1-M2 / TS-1-X)=1.0-40.0:100.

[0022] In the above technical solution, further, in the method one, the method for loading the first metal oxide and the second metal oxide on TS-1-X@SiO2 is: adding TS-1-X@SiO2 to the salt solution of the first metal and the salt solution of the second metal, according to the total mass of the metal oxides: TS-1-X@SiO2 = 0.25-20.0:100, impregnating for 4-36 hours, filtering, washing, drying at 80-150°C for 2-48 hours and calcining in air at 400-650°C for 4-48 hours.

[0023] In the above technical solution, further, in the second method, the method of loading the first metal oxide and the second metal oxide on TS-1-X is: adding TS-1-X to the salt solution of the first metal and the salt solution of the second metal, according to the total mass of the metal oxide: TS-1-X = 0.25-20.0:100, impregnating for 4-36 hours, filtering, washing, drying at 80-150°C for 2-48 hours and calcining in air at 400-650°C for 4-48 hours.

[0024] In the above technical solution, further, the mass of the second metal oxide: the mass of the first metal oxide = x: 1, wherein 0 <x≤2;

[0025] The salt solution of the first metal is at least one of Co(NO3)2, Co(NO3)3, CoSO4, Co2(SO4)3, Co(C2H6O2)3, Co(C2H6O2)2, CoCl2, and CoCl3; the salt solution of the second metal is at least one of Mn(NO3)2, Mn(NO3)4, MnSO4, Mn(SO4)2, Mn(C2H3O2)2, Mn(C2H3O2)4, MnCl2, and MnCl4.

[0026] Another aspect of the present invention provides an application of the catalyst prepared by the above preparation method in the oxidation reaction of ethylbenzene, wherein the catalyst is applied to the oxidation reaction of ethylbenzene in the presence of an oxidant, after adding a solvent and an auxiliary agent;

[0027] The reaction conditions are as follows: reaction temperature of 50-160° C., reaction time of 0.5-24 h, reaction pressure of 0.5-20 atm; catalyst addition amount of 0.5-25% of the mass of ethylbenzene; oxidant addition amount of 2-30 times of the mass of ethylbenzene; solvent addition amount of 1-25 times of the mass of ethylbenzene; and auxiliary agent addition amount of 0.5-25% of the mass of ethylbenzene.

[0028] The beneficial effects of the present invention are:

[0029] The present invention sequentially and continuously modifies TS-1 using alkali and silanization, followed by loading it with two metal oxides, to produce an environmentally friendly, highly active, and easily separable catalyst for catalyzing the oxidation of ethylbenzene. The catalyst is suitable for the green synthesis of acetophenone and phenylethanol from ethylbenzene using hydrogen peroxide, molecular oxygen, or potassium permanganate as oxidants. In the oxidation of ethylbenzene to produce high-value-added products such as acetophenone and phenylethanol, the catalyst exhibits high activity, good selectivity for the target product, and easy catalyst reuse and regeneration, significantly reducing energy consumption for product separation. Furthermore, the catalyst is simple to prepare, environmentally friendly, easily separable and recyclable, and has a relatively low reaction temperature. DETAILED DESCRIPTION

[0030] Example 1

[0031] The TS-1 zeolite catalyst of the present invention is continuously modified by alkali, silanization and two metal oxides, and is prepared in the following steps:

[0032] a. Under normal temperature and pressure with stirring, TS-1 was added to a 0.6 mol / L tetrapropylammonium hydroxide solution in a ratio of 1 g:5 g. After stirring, the mixture was transferred to a reactor and reacted at a constant temperature of 150°C for 24 hours. After the reaction, the mixture was centrifuged, washed, dried, and calcined in air at 550°C for 6 hours to obtain TS-1-X.

[0033] b. TS-1-X was placed in a cyclohexane solution of 5.0% by mass of tetraethyl orthosilicate and allowed to stand for 12 hours. The mixture was then heated to reflux at 85°C until the alkane was evaporated. The catalyst was then calcined in air at 550°C for 4 hours to obtain the catalyst TS-1-X@SiO2. The mass ratio of the cyclohexane solution of 5.0% by mass of tetraethyl orthosilicate to TS-1-X was 10:1, and the ratio of m(SiO2):m(TS-1-X) was 1:10.

[0034] c. Mix Co(C2H3O2)2, Mn(C2H3O2)2 and water to prepare a solution, where the mass ratio of Co(C2H3O2)2 to water is 1:10, and Mn(C2H3O2)2 is 0.01-0.1% of the mass of Co(C2H3O2)2. Add TS-1-X@SiO2 to the solution, stir evenly, and soak at room temperature for 12 hours. After filtration and washing, dry it into powder at 100°C, raise the temperature to 550°C, and calcine it in air for 6 hours.

[0035] Example 2

[0036] The TS-1 zeolite catalyst of the present invention is continuously modified by alkali, silanization and two metal oxides, and is prepared in the following steps:

[0037] a. Under normal temperature, normal pressure and stirring conditions, TS-1 was added to a 0.6 mol / L tetrapropylammonium hydroxide solution in a ratio of 1 g:0.609 g. After stirring evenly, the mixture was transferred to a reactor and reacted at a constant temperature of 150°C for 24 hours. After the reaction, the mixture was filtered, washed, dried, and calcined at 550°C in air for 6 hours to obtain TS-1-X.

[0038] b. TS-1-X was placed in a cyclohexane solution of 5.0% by mass of tetraethyl orthosilicate and allowed to stand for 12 hours. The mixture was then heated to reflux at 85°C until the alkane was evaporated. The catalyst was then calcined in air at 550°C for 4 hours to obtain the catalyst TS-1-X@SiO2. The mass ratio of the cyclohexane solution of 5.0% by mass of tetraethyl orthosilicate to TS-1-X was 10:1, and the ratio of m(SiO2):m(TS-1-X) was 1:10.

[0039] c. Mix Co(C2H3O2)2, Mn(C2H3O2)2 and water to prepare a solution, where the mass ratio of Mn(C2H3O2)2 to water is 1:10, and Co(C2H3O2)2 accounts for 0.01-0.1% of the mass of Mn(C2H3O2)2. Add TS-1-X@SiO2 to the solution, stir evenly, and soak at room temperature for 12 hours. After filtration and washing, dry it into powder at 100℃, raise the temperature to 550℃ and calcine in air for 6 hours.

[0040] Example 3

[0041] The TS-1 zeolite catalyst of the present invention is continuously modified by alkali, silanization and two metal oxides, and is prepared in the following steps:

[0042] a. TS-1 was added to a 0.6 mol / L tetrapropylammonium hydroxide solution at room temperature and pressure with stirring. The ratio of TS-1 to tetrapropylammonium hydroxide was 1 g:0.609 g. After stirring, the mixture was transferred to a reactor and reacted at a constant temperature of 150°C for 24 hours. After the reaction, the mixture was centrifuged, washed, dried, and calcined in air at 550°C for 6 hours to obtain TS-1-X.

[0043] b. TS-1-X was placed in a cyclohexane solution of 5.0% ethyl orthosilicate and allowed to stand for 12 hours. The mixture was then heated to reflux at 85°C until the alkane was evaporated. The mixture was then calcined in air at 550°C for 4 hours to obtain TS-1-X@SiO2. The mass ratio of the cyclohexane solution of 5.0% ethyl orthosilicate to TS-1-X was 10:1, and the ratio of m(SiO2):m(TS-1-X) was 1:10.

[0044] c. Mix Co(C2H3O2)2, Mn(C2H3O2)2 and water in a mass ratio of 1:1:10 to prepare a mixed solution, add TS-1-X@SiO2 to the mixed solution, stir evenly and soak at room temperature for 12 hours, filter and wash, dry into powder at 100℃, and heat to 550℃ through programmed heating and calcinate in air for 6 hours.

[0045] Example 4

[0046] The TS-1 zeolite catalyst of the present invention is continuously modified by alkali, silanization and two metal oxides, and is prepared in the following steps:

[0047] a. TS-1 was added to a 0.6 mol / L tetrapropylammonium hydroxide solution at room temperature and pressure with stirring. The ratio of TS-1 to tetrapropylammonium hydroxide solution was 1 g:5 g. After stirring, the mixture was transferred to a polytetrafluoroethylene-lined reactor and reacted at a constant temperature of 150°C for 24 hours. After the reaction, the mixture was centrifuged, washed, dried, and calcined in air at 550°C for 6 hours to obtain TS-1-X.

[0048] b. Co(C2H3O2)2, Mn(C2H3O2)2 and water were mixed to prepare a solution, wherein the mass ratio of Co(C2H3O2)2 to water was 1:10, and Mn(C2H3O2)2 was 0.01-0.1% of the mass of Co(C2H3O2)2. TS-1-X was added to the mixture, stirred evenly, and immersed at room temperature for 12 hours. After filtering and washing, it was dried at 100°C to form a powder, and the temperature was programmed to 550°C and calcined in air for 6 hours to obtain Co / TS-1-X.

[0049] c. Place Co / TS-1-X in a cyclohexane solution of 5.0% by mass of tetraethyl orthosilicate and allow it to stand for 12 hours, heat it to reflux at 85°C until the alkane is evaporated, and calcine it in air at 550°C for 4 hours to obtain the catalyst SiO2@Co / TS-1-X. The mass ratio of the cyclohexane solution of 5.0% by mass of tetraethyl orthosilicate to Co / TS-1-X is 10:1, and the m(SiO2):m(Co / TS-1-X) is 1:10.

[0050] Example 5

[0051] The TS-1 zeolite catalyst of the present invention is continuously modified by alkali, silanization and two metal oxides, and is prepared in the following steps:

[0052] a. Under normal temperature, normal pressure and stirring conditions, TS-1 was added to a 0.6 mol / L tetrapropylammonium hydroxide solution in a ratio of 1 g:0.609 g. After stirring evenly, the mixture was transferred to a reactor and reacted at a constant temperature of 150°C for 24 hours. After the reaction, the mixture was filtered, washed, dried, and calcined at 550°C in air for 6 hours to obtain TS-1-X.

[0053] b. Co(C2H3O2)2, Mn(C2H3O2)2 and water were mixed to prepare a solution, wherein the mass ratio of Mn(C2H3O2)2 to water was 1:10, and Co(C2H3O2)2 was 0.01-0.1% of the mass of Mn(C2H3O2)2. TS-1-X was added to the solution, stirred evenly, and immersed at room temperature for 12 hours. After filtration and washing, it was dried at 100°C to form a powder, and the temperature was programmed to 550°C and calcined in air for 6 hours to obtain Mn / TS-1-X.

[0054] c. Place Mn / TS-1-X in a cyclohexane solution of 5.0% by mass of tetraethyl orthosilicate and allow it to stand for 12 hours, heat it to reflux at 85°C until the alkane is evaporated, and calcine it in air at 550°C for 4 hours to obtain the catalyst SiO2@Mn / TS-1-X. The mass ratio of the cyclohexane solution of 5.0% by mass of tetraethyl orthosilicate to Mn / TS-1-X is 10:1, and the m(SiO2):m(Mn / TS-1-X) is 1:10.

[0055] Example 6

[0056] The TS-1 zeolite catalyst of the present invention is continuously modified by alkali, silanization and two metal oxides, and is prepared in the following steps:

[0057] a. Under normal temperature, normal pressure and stirring conditions, TS-1 was added to a 0.6 mol / L tetrapropylammonium hydroxide solution in a ratio of 1 g:0.609 g. After stirring evenly, the mixture was transferred to a reactor and reacted at a constant temperature of 150°C for 24 hours. After the reaction, the mixture was filtered, washed, dried, and calcined at 550°C in air for 6 hours to obtain TS-1-X.

[0058] b. Co(C2H3O2)2, Mn(C2H3O2)2 and water were mixed in a mass ratio of 1:1:10 to prepare a mixed solution, TS-1-X was added to the mixed solution, stirred evenly and immersed at room temperature for 12 hours, filtered, washed, dried at 100°C to form a powder, and programmed to 550°C and calcined in air for 6 hours to obtain Co-Mn / TS-1-X;

[0059] c. Place Co-Mn / TS-1-X in a cyclohexane solution of 5.0% by mass of tetraethyl orthosilicate and let it stand for 12 hours, heat it to reflux at 85°C until the alkane is evaporated, and calcine it in air at 550°C for 4 hours to obtain the catalyst SiO2@Co-Mn / TS-1-X. The mass ratio of the cyclohexane solution of 5.0% by mass of tetraethyl orthosilicate to Co-Mn / TS-1-X is 10:1, and the m(SiO2):m(Co-Mn / TS-1-X) is 1:10.

[0060] Comparative Example 1: Synthesis of SiO2

[0061] (1) A certain amount of ethyl orthosilicate and anhydrous ethanol were uniformly mixed in a molar ratio of 1:5 and stirred for 1 hour to prepare solution A;

[0062] (2) The obtained solution was stirred evenly and then allowed to stand for 24 hours, dried at 80°C, and calcined in air at 300°C for 6 hours to obtain the catalyst, which was recorded as SiO2.

[0063] Comparative Example 2: Synthesis of TiO2

[0064] (1) Anhydrous ethanol, water, concentrated nitric acid, and butyl titanate were mixed uniformly in a molar ratio of 30:300:1.8:1 to prepare solution B;

[0065] (2) The obtained solution was stirred evenly and then allowed to stand for 24 hours, filtered, washed, dried at 80°C, and calcined in air at 300°C for 6 hours to obtain the catalyst, which was recorded as TiO2.

[0066] Comparative Example 3: Synthesis of TiO2-SiO2

[0067] (1) Under vigorous stirring, the solution B described in Comparative Example 2 was added to the solution A described in Comparative Example 1, and the mixture was kept at 50°C and 80°C for 2 h respectively;

[0068] (2) The obtained wet gel was vacuum dried at 100°C for 6 h and then calcined at 400°C for 6 h to prepare titanium silicon nanocomposite oxide, which was recorded as TiO2-SiO2.

[0069] Comparative Example 4: Synthesis of TS-1

[0070] TS-1 molecular sieve was synthesized under hydrothermal conditions at 160°C using TEOS as silicon source, TBOT as titanium source, tetrapropylammonium hydroxide (TPAOH) as template, and the molar ratio of materials being SiO2:TiO2:TPAOH:CH3CH2OH:H2O=1:0.0167:0.4:1.5:23.5.

[0071] Comparative Example 5: Synthesis of TS-1-X

[0072] Under normal temperature, normal pressure and stirring conditions, TS-1 was added to a 0.6 mol / L tetrapropylammonium hydroxide solution in a ratio of 1 g:5 g. After stirring evenly, the mixture was transferred to a reactor and reacted at a constant temperature of 150°C for 24 hours. After the reaction was completed, the mixture was centrifuged, washed, dried, and calcined at 550°C in air for 6 hours to obtain TS-1-X.

[0073] Comparative Example 6: Synthesis of TS-1-X@SiO2

[0074] (1) TS-1 was added to a 0.6 mol / L tetrapropylammonium hydroxide solution at room temperature and pressure with stirring. The ratio of TS-1 to tetrapropylammonium hydroxide solution was 1 g:5 g. After stirring evenly, the mixture was transferred to a reactor and reacted at a constant temperature of 150°C for 24 h. After the reaction, the mixture was centrifuged, washed, dried, and calcined at 550°C in air for 6 h to obtain TS-1-X.

[0075] (2) TS-1-X was placed in a cyclohexane solution of 5.0%-20.0% by mass of tetraethyl orthosilicate and allowed to stand for 12 hours, heated to reflux at 85°C until the alkane was evaporated, and calcined in air at 550°C for 4 hours. The mass ratio of the cyclohexane solution of 5.0%-20.0% by mass of tetraethyl orthosilicate to TS-1-X was 10-40:1, and m(SiO2):m(TS-1-X) was 1-20:50 to obtain the catalyst TS-1-X@SiO2.

[0076] Application Example 1: Catalytic Oxidation Performance Evaluation of Catalysts

[0077] The catalytic ethylbenzene oxidation activities of Examples 1-6 and Comparative Examples 1-6 were measured.

[0078] The specific operation process is as follows: the reaction temperature is 50-90°C, the reaction time is 1-6h, the amount of oxidant added is: n(EB):n(H2O2)=1:4-25, the amount of catalyst used is 1.25%-20% of the raw material, and the amount of auxiliary agent used is 1.25%-20% of the raw material.

[0079] Table 1 Reaction results of Examples 1-6

[0080]

[0081] Table 2 Reaction results of comparative examples 1-6

[0082]

[0083] Application Example 2: Catalyst Recycling Performance Evaluation

[0084] Catalysts were synthesized according to Examples 3 and 6, and their ethylbenzene oxidation performance was measured. The recovered catalysts were regenerated in an air atmosphere at 500-600°C, and their ethylbenzene oxidation performance was measured.

[0085] The specific operation process is as follows: the reaction temperature is 50-90°C, the reaction time is 1-6 hours, the amount of oxidant added is: n(EB):n(H2O2) = 1:4-25, the amount of catalyst used is 1.25-20% of the raw material, and the amount of auxiliary agent used is 1.25-20% of the raw material. The specific reaction results are shown in Table 3.

[0086] Table 3 Catalyst regeneration reaction results

[0087]

[0088] Experimental results show that Examples 1-6 of the present invention have the highest catalytic ethylbenzene oxidation activity, outperforming SiO2, TiO2, TiO2-SiO2, TS-1, alkali-treated catalysts alone, and alkali-treated catalysts silanized after alkali treatment. Although both TS-1 zeolite and TiO2-SiO2 oxide contain Ti and Si, their catalytic ethylbenzene oxidation performance differs significantly due to differences in the bonding mechanisms of Ti, O, and Si and their distinct pore structure characteristics. TS-1 zeolite has a pore structure similar in size to that of the reactants and reaction products, fully utilizing the Ti active species within the molecular sieve framework to achieve optimal reaction performance. Catalysts prepared from TS-1 zeolite modified with alkali, silanization, and two metal oxides exhibit optimal ethylbenzene oxidation activity and selectivity for the desired product. The catalyst of the present invention is suitable for the green synthesis of acetophenone and phenylethyl alcohol from ethylbenzene using hydrogen peroxide, molecular oxygen, or potassium permanganate as oxidants. In the oxidation of ethylbenzene to produce high-value-added products such as acetophenone and phenylethanol, the catalyst exhibits high activity, good selectivity for the target product, and easy catalyst reuse and regeneration, significantly reducing energy consumption for product separation. Furthermore, the catalyst is simple to prepare, environmentally friendly, easily separated and recovered, and operates at a relatively low reaction temperature.

[0089] The above-described embodiments are only preferred embodiments of the present invention, and are not intended to be all feasible embodiments of the present invention. Any obvious modifications made by a person skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a TS-1 zeolite catalyst modified by alkali, silanization and two metal oxides, characterized in that: The method comprises the following steps: a. At room temperature and pressure with stirring, TS-1 zeolite is added to an alkaline solution, stirred evenly, and then transferred to a reactor. The reaction is carried out at a constant temperature of 100-220°C for 6-36 hours. After the reaction, it is dried at 80-150°C and then calcined in air at 400-650°C for 4-48 hours to obtain TS-1-X. b The TS-1-X obtained in step a is modified, wherein the modification is one of the following two methods: Method 1: TS-1-X obtained in step a is subjected to silanization modification treatment with an alkane solution of orthosilicate to obtain a silanized TS-1 zeolite, recorded as TS-1-X@SiO2, and then the first metal oxide and the second metal oxide are loaded on TS-1-X@SiO2 as a carrier, and the catalyst is obtained by filtering, washing, drying and calcining. The method for silanization modification of TS-1-X is as follows: TS-1-X is immersed in an alkane solution of orthosilicate with a mass fraction of 2% to 40% for 6 to 48 hours, heated under reflux at 80 to 150°C until the alkane is evaporated, and calcined in air at 400 to 650°C for 4 to 48 hours; Method 2: TS-1-X obtained in step a is used as a carrier to load the first metal oxide and the second metal oxide, and the catalyst loaded with the two metal oxides is obtained by filtering, washing, filtering, drying and calcining, and then M1-M2 / TS-1-X is subjected to silanization modification treatment with an alkane solution of orthosilicate, followed by drying and calcining to obtain the catalyst; The method for silanization modification of M1-M2 / TS-1-X is as follows: M1-M2 / TS-1-X is immersed in an alkane solution of orthosilicate with a mass fraction of 2%-40% for 6-48 hours, heated under reflux at 80-150°C until the alkane is evaporated, and calcined in air at 400-650°C for 4-48 hours; The metal in the first metal oxide is Co; The metal in the second metal oxide is Mn.

2. The method for preparing a TS-1 zeolite catalyst continuously modified by alkali, silylation and two metal oxides according to claim 1, characterized in that: In the step a, the concentration of the alkaline solution is 0.1-2.0 mol / L; The ratio of alkaline solution to TS-1 zeolite is 1 g: 0.04-1.2 g; The base is an organic base or an inorganic base. The organic base is at least one of tetrapropylammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetraisopropylammonium hydroxide, tetraisobutylammonium hydroxide, and tetrabutylammonium hydroxide. The inorganic base is at least one of sodium hydroxide, potassium hydroxide, and ammonia water.

3. The method for preparing a TS-1 zeolite catalyst continuously modified by alkali, silylation and two metal oxides according to claim 1, characterized in that: In the method 1, the mass ratio of the alkane solution of orthosilicate to TS-1-X is 5-50:1, and m (SiO2): m (TS-1-X)=1.0-40.0:

100.

4. The method for preparing a TS-1 zeolite catalyst continuously modified by alkali, silylation and two metal oxides according to claim 1, characterized in that: In the second method, the mass ratio of the alkane solution of orthosilicate to M1-M2 / TS-1-X is 5-50:1, and m (SiO2): m (M1-M2 / TS-1-X)=1.0-40.0:

100.

5. The method for preparing a TS-1 zeolite catalyst continuously modified by alkali, silylation and two metal oxides according to claim 1, characterized in that: In the first method, the method for loading the first metal oxide and the second metal oxide on TS-1-X@SiO2 is as follows: TS-1-X@SiO2 is added to the salt solution of the first metal and the salt solution of the second metal, and the total mass of the metal oxides is: TS-1-X@SiO2 = 0.25-20.0:100, impregnated for 4-36 hours, filtered, washed, dried at 80-150°C for 2-48 hours, and calcined in air at 400-650°C for 4-48 hours.

6. The method for preparing a TS-1 zeolite catalyst continuously modified by alkali, silylation and two metal oxides according to claim 1, characterized in that: In the second method, the method for loading the first metal oxide and the second metal oxide on TS-1-X is as follows: TS-1-X is added to the salt solution of the first metal and the salt solution of the second metal, according to the total mass of the metal oxide: TS-1-X = 0.25-20.0:100, impregnated for 4-36 hours, filtered, washed, dried at 80-150 ° C for 2-48 hours, and calcined in air at 400-650 ° C for 4-48 hours.

7. The preparation method according to claim 5 or 6, characterized in that: The mass of the second metal oxide: the mass of the first metal oxide = x: 1, where 0 <x≤2; The salt solution of the first metal is at least one of Co(NO3)2, Co(NO3)3, CoSO4, Co2(SO4)3, Co(C2H3O2)3, Co(C2H3O2)2, CoCl2, and CoCl3; The salt solution of the second metal is at least one of Mn(NO3)2, Mn(NO3)4, MnSO4, Mn(SO4)2, Mn(C2H3O2)2, Mn(C2H3O2)4, MnCl2, and MnCl4.

8. Use of a TS-1 zeolite catalyst prepared by the preparation method according to any one of claims 1 to 7 and continuously modified by alkali, silylation and two metal oxides in the oxidation reaction of ethylbenzene, characterized in that: The catalyst is used in the oxidation reaction of ethylbenzene in the presence of an oxidant, after adding a solvent and an auxiliary agent; The reaction conditions are as follows: reaction temperature of 50-160°C, reaction time of 0.5-24 h, reaction pressure of 0.5-20 atm; catalyst addition amount of 0.5-25% of the mass of ethylbenzene; oxidant addition amount of 2-30 times the mass of ethylbenzene; solvent addition amount of 1-25 times the mass of ethylbenzene; and auxiliary agent addition amount of 0.5-25% of the mass of ethylbenzene.

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