Intrinsic amphiphilic catalyst for water-phase ammoximation reaction and preparation method of intrinsic amphiphilic catalyst

Abstract

The invention provides an intrinsic amphiphilic catalyst for a water-phase ammoximation reaction and a preparation method of the intrinsic amphiphilic catalyst, and belongs to the technical field of catalyst preparation. The titanium silicalite molecular sieve is subjected to intrinsic modification by using acid and corresponding aluminum salt, so that the titanium silicalite molecular sieve has amphipathy, and further shows excellent catalytic activity in water-phase oximation. The preparation method of the catalyst is simple in process and easy to operate, and compared with a conventional titanium silicalite molecular sieve catalyst, the conversion rate of the reaction and the product selectivity can be remarkably improved in the ketone ammoximation reaction.

Description

Technical Field

[0001] The present invention belongs to the field of catalyst preparation, and particularly relates to an intrinsic amphiphilic catalyst for aqueous phase ammoximation reaction and a preparation method thereof. Background Art

[0002] Titanium silicalite molecular sieve refers to a class of heteroatom molecular sieves containing transition metal element Ti in the crystal framework. Since the titanium-containing porous material has excellent catalytic performance and environmentally friendly green reaction characteristics, it has been a research hotspot in the academic and industrial circles since its appearance. Scientific researchers have been committed to developing new types of titanium silicalite molecular sieves. In the past thirty years, a series of major breakthroughs have been made in the synthesis of titanium silicalite molecular sieves, and it has become a large family, including TS-1, TS-2, Ti-Beta, Ti-ZSM-12, Ti-MOR, Ti-ITQ-6, Ti-MWW, Ti-FER, Ti-MCM-41, etc. Some titanium silicalite molecular sieves show excellent catalytic performance in the liquid-phase ammoximation reaction of ketones.

[0003] The liquid-phase ammoximation reaction of ketones uses ketone, ammonia water, and hydrogen peroxide as reaction raw materials for the ammoximation reaction. The reaction is carried out at a reaction temperature below 100°C, and the reaction conditions are mild and the reaction by-products are environmentally friendly. Since the miscibility of hydrogen peroxide and cyclohexanone is poor, most current liquid-phase ammoximation reactions of ketones use organic solvents to ensure sufficient contact between the catalyst, ketone, ammonia, and hydrogen peroxide to achieve better reaction effects. However, the use of organic solvents undoubtedly brings more process steps, energy consumption, and costs in the later product separation process, and it also affects the product quality. Therefore, in recent years, an aqueous phase ammoximation reaction without organic solvents has been developed. After the reaction, the materials do not need to be rectified to recover the solvent, which greatly simplifies the production process. However, since the currently used titanium silicalite molecular sieve is a hydrophilic material, this greatly reduces the contact between the catalyst and the raw material ketone. The hydroxylamine generated by the reaction of ammonia and hydrogen peroxide in the water layer cannot contact the cyclohexanone in the oil phase in time, resulting in too high a concentration of hydroxylamine and its own decomposition, significantly reducing the reaction performance.

[0004] Based on the above background reasons, people have started to study the modification of molecular sieves. The main direction is to improve the lipophilicity of zeolite molecular sieves, making them more inclined to distribute at the oil-water phase interface rather than staying in the water phase, thereby improving the reaction performance. Chinese invention patent CN 118204117 A discloses a synthesis method of an amphiphilic catalyst, that is, a hierarchical porous titanium silicate molecular sieve modified by a hydrophobic silane, which is used in the reaction of toluene hydroxylation to prepare cresol. The hydrophobic silane is selected from at least one of methyltrimethoxysilane, aminopropyltriethoxysilane, aminopropyltrimethoxysilane, phenyltriethoxysilane, and octyltrimethoxysilane. After the zeolite molecular sieve catalyst is grafted and modified with a silanization reagent and deactivated due to carbon deposition, the carbon deposition cannot be removed by calcination. The catalyst can only be regenerated by treatment with hydrogen peroxide to prevent the silanization graft modification from being removed and thus losing its amphiphilicity. However, when treated with methods such as hydrogen peroxide, on the one hand, the treatment is not clean, and on the other hand, the cost is high and there are safety risks. Summary of the Invention

[0005] The present invention provides an intrinsic amphiphilic catalyst for the aqueous-phase ammoximation reaction and a preparation method thereof. Without using a silanization reagent, the catalyst is hydrothermally treated, with simple operation and low cost, and can maintain its amphiphilicity at 550 °C, showing excellent performance in the aqueous-phase ammoximation reaction of ketones.

[0006] To achieve the above effects and purposes, the present invention adopts the following technical solutions.

[0007] The present invention provides an intrinsic amphiphilic catalyst obtained by hydrothermally treating a titanium silicate molecular sieve with an aqueous solution, where the aqueous solution contains an acid and the aluminum salt corresponding to the acid.

[0008] The present invention also provides a preparation method of the above-mentioned intrinsic amphiphilic catalyst. Using a titanium silicate molecular sieve as a raw material, the titanium silicate molecular sieve is hydrothermally treated with an aqueous solution, and after treatment, it is filtered, washed, dried, and calcined to obtain the intrinsic amphiphilic catalyst; the aqueous solution contains an acid and the aluminum salt corresponding to the acid.

[0009] Further, the titanium silicate molecular sieve is selected from at least one of TS-1, Ti-MWW, and Ti-MOR.

[0010] Further, the acid is selected from at least one of sulfuric acid, hydrochloric acid, and nitric acid; the aluminum salt corresponding to the acid is selected from at least one of aluminum sulfate, aluminum chloride, and aluminum nitrate.

[0011] Further, the solid-liquid mass ratio of the titanium silicate molecular sieve to the aqueous solution is 1:3 to 10.

[0012] Further, the solid-liquid mass ratio of the titanium silicalite molecular sieve to the aqueous solution is 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, or any value between any two of the above.

[0013] Further, in the aqueous solution, the mass concentration of the acid is 1% - 6%, and the mass concentration of the aluminum salt corresponding to the acid is 3% - 10%.

[0014] Further, in the aqueous solution, the mass concentration of the acid is 1%, 2%, 3%, 4%, 5% or 6%, or any value between any two of the above.

[0015] Further, in the aqueous solution, the mass concentration of the aluminum salt corresponding to the acid is 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, or any value between any two of the above.

[0016] Further, the treatment temperature of the hydrothermal treatment is 100 - 150 °C, and the treatment time is 24 - 48 h.

[0017] Further, the treatment temperature of the hydrothermal treatment is 100 °C, 110 °C, 120 °C, 130 °C, 140 °C or 150 °C, or any value between any two of the above.

[0018] Further, the treatment time of the hydrothermal treatment is 24 h, 28 h, 30 h, 35 h, 40 h, 42 h, 46 h or 48 h, or any value between any two of the above.

[0019] Further, the drying temperature is 80 - 120 °C, and the calcination temperature is 500 - 600 °C.

[0020] The present invention also provides an application of the above-mentioned intrinsic amphiphilic catalyst in the aqueous-phase ammoximation reaction of ketones.

[0021] Further, in the aqueous-phase ammoximation reaction of ketones, the molar ratio of H2O2, ammonia to ketones is 1.01 - 1.30:1.10 - 1.90:1, the dosage of the intrinsic amphiphilic catalyst is 4% - 10% of the mass of the ketones, and the reaction temperature is 60 - 95 °C.

[0022] Further, the ketones are selected from at least one of methyl ethyl ketone, cyclohexanone and acetone.

[0023] The advantages of the technical solution of the present invention are as follows: Through the easily operable hydrothermal treatment method, the present invention intrinsically modifies the titanium silicalite molecular sieve, improves the lipophilicity of the titanium silicalite molecular sieve catalyst, makes it amphiphilic, and further shows excellent catalytic activity in the aqueous-phase oxime reaction. The catalyst preparation method provided by the present invention has a simple process and is easy to operate. Compared with the conventional titanium silicalite molecular sieve catalyst, it can significantly improve the reaction conversion rate and product selectivity in the aqueous-phase ammoximation reaction of ketones. Description of the Drawings

[0024] Figure 1 、 Figure 2 and Figure 3 are the XRD patterns of catalysts A-1, A-5, and A-7, respectively; Figure 4 、 Figure 5 and Figure 6 are the SEM photos of catalysts A-1, A-5, and A-7, respectively. Detailed Embodiments

[0025] The following examples will further illustrate the present invention, but do not limit the content of the present invention thereby.

[0026] The reagents used in the examples are all commercially available chemical pure reagents or industrial raw materials.

[0027] For better illustration of the present invention, the preparation process of titanium silicalite is described, but it is not limited to the titanium silicalite prepared by the following method.

[0028] Preparation method of titanium silicalite TS-1: Using silica sol as the silicon source, tetrabutyl titanate as the titanium source, and tetrapropylammonium bromide as the template agent, crystallize at 150-200 °C for 12-48 h, and obtain titanium silicalite after filtration, washing, drying, and calcination.

[0029] Preparation method of titanium silicalite Ti-MWW: Using boric acid as the boron source, silica sol as the silicon source, and piperidine as the template agent, crystallize at 90-100 °C for 24-48 h, and obtain B-MWW after filtration, washing, and drying. After the B-MWW is deboronated by acid treatment, tetrabutyl titanate is used as the titanium source for secondary hydrothermal crystallization, crystallize at 150-180 °C for 48-72 h, and obtain titanium silicalite Ti-MWW molecular sieve after filtration, washing, drying, and calcination.

[0030] Preparation method of titanium silicalite Ti-MOR: Using MOR molecular sieve as the carrier, after acid treatment, using titanium tetrachloride as the titanium source, carry out gas-phase treatment at 400-600 °C for 12-24 h, and obtain Ti-MOR molecular sieve after washing with water, drying, and calcination.

[0031] Prepare an aqueous solution composed of an acid and its corresponding aluminum salt: First weigh the weight of water, add the aluminum salt, stir to dissolve, and then add the corresponding acid and stir evenly to obtain the treatment solution.

[0032] The intrinsic amphiphilic catalyst provided by the present invention is used in the aqueous-phase ammoximation reaction of ketones. The catalyst, ammonia water, and ketone are added to a reaction kettle, and the temperature is raised to the reaction temperature under stirring conditions. Hydrogen peroxide is added dropwise. After the addition of hydrogen peroxide is completed, timing starts for 1 h. Ethanol or methanol is quantitatively added to completely dissolve the product. Samples are taken, and the conversion rate and selectivity of the ketone are analyzed quantitatively by chromatography.

[0033] The catalyst obtained by the above method provided by the present invention can be applied to the aqueous-phase ammoximation reaction of ketones.

[0034] Further, in the above technical solution, in the aqueous-phase ammoximation reaction of ketones, the molar ratio of H2O2, ammonia to ketones is 1.01~1.30:1.10~1.90:1, the dosage of the intrinsic amphiphilic catalyst is 4%~10% of the mass of the ketones, and the reaction temperature is 60~95 °C.

[0035] The calculation method of the reaction results is as follows: The conversion rate X of the ketone = the number of moles of the reacted ketone / the total number of moles of the ketone * 100%; The selectivity S of the oxime = the number of moles of the oxime / the number of moles of the reacted ketone * 100%.

[0036] The XRD characterization of the catalyst was measured by an X-ray diffractometer (PANalytical, X’Pert3 Powder).

[0037] The scanning electron microscope (SEM) characterization of the catalyst was measured by a scanning electron microscope (Hitachi, SU5000). Example 1

[0038] Catalyst preparation: An aqueous solution of a mixture of nitric acid and aluminum nitrate was prepared, in which the nitric acid content was 5% (mass fraction, the same below) and the aluminum nitrate content was 8%. 10 g of titanium silicate molecular sieve Ti-MOR was added to 80 g of the above aqueous solution, stirred evenly, loaded into a crystallization kettle with a Teflon inner lining, hydrothermally treated at 150 °C for 48 h, and then obtained the intrinsic amphiphilic catalyst after cooling, filtering, washing, drying at 100 °C for 12 h, and calcining at 500 °C for 6 h. The catalyst was numbered A-1. The XRD pattern and SEM photo of the catalyst are as Figure 1 and Figure 4 . It shows that catalyst A-1 has the MOR topological structure and crystal grain morphology of the Ti-MOR molecular sieve.

[0039] Aqueous-phase ammoximation reaction of cyclohexanone: Add 1 g of catalyst, 102 g of ammonia water (concentration 5%), and 19.6 g of cyclohexanone into the reaction kettle. Heat up to 80 °C under stirring conditions, and add dropwise 25 g of hydrogen peroxide (concentration 30%). Start timing for 1 h after the addition of hydrogen peroxide is completed. Add 150 g of ethanol to completely dissolve the product, take samples, and quantitatively analyze the conversion rate and selectivity of cyclohexanone by chromatography. The reaction results are shown in Table 1. Example 2

[0040] Catalyst preparation: Prepare an aqueous solution of mixed nitric acid and aluminum nitrate, where the nitric acid content is 6% and the aluminum nitrate content is 5%. Add 10 g of titanium silicate molecular sieve Ti-MOR into 30 g of the above aqueous solution, stir evenly, load it into a crystallization kettle with a Teflon liner, perform hydrothermal treatment at 120 °C for 36 h, and then obtain the intrinsic amphiphilic catalyst after cooling, filtering, washing, drying at 100 °C for 12 h, and calcining at 500 °C for 6 h. The catalyst number is A-2.

[0041] Aqueous phase ammoximation reaction of cyclohexanone: The reaction conditions are the same as those in Example 1, the catalyst is A-2, and the reaction results are shown in Table 1. Example 3

[0042] Catalyst preparation: Prepare an aqueous solution of mixed nitric acid and aluminum nitrate, where the nitric acid content is 4% and the aluminum nitrate content is 6%. Add 10 g of titanium silicate molecular sieve Ti-MOR into 100 g of the above aqueous solution, stir evenly, load it into a crystallization kettle with a Teflon liner, perform hydrothermal treatment at 120 °C for 48 h, and then obtain the intrinsic amphiphilic catalyst after cooling, filtering, washing, drying at 100 °C for 12 h, and calcining at 500 °C for 6 h. The catalyst number is A-3.

[0043] Aqueous phase ammoximation reaction of cyclohexanone: The reaction conditions are the same as those in Example 1, the catalyst is A-3, and the reaction results are shown in Table 1. Example 4

[0044] Catalyst preparation: Prepare an aqueous solution of mixed sulfuric acid and aluminum sulfate, where the sulfuric acid content is 2% and the aluminum sulfate content is 3%. Add 10 g of titanium silicate molecular sieve Ti-MOR into 50 g of the above aqueous solution, stir evenly, load it into a crystallization kettle with a Teflon liner, perform hydrothermal treatment at 120 °C for 48 h, and then obtain the intrinsic amphiphilic catalyst after cooling, filtering, washing, drying at 100 °C for 12 h, and calcining at 500 °C for 6 h. The catalyst number is A-4.

[0045] Aqueous phase ammoximation reaction of cyclohexanone: The reaction conditions are the same as those in Example 1, the catalyst is A-4, and the reaction results are shown in Table 1. Example 5

[0046] Catalyst preparation: Prepare an aqueous solution of a mixture of sulfuric acid and aluminum sulfate, with a sulfuric acid content of 2% and an aluminum sulfate content of 3%. Add 10 g of titanium silicate molecular sieve TS-1 to 50 g of the above aqueous solution, stir evenly, load it into a crystallization kettle with a Teflon liner, perform hydrothermal treatment at 120 °C for 48 h, and then obtain the intrinsic amphiphilic catalyst after cooling, filtering, washing, drying at 100 °C for 12 h, and calcining at 500 °C for 6 h. The catalyst number is A-5. The XRD pattern and SEM photo of the catalyst are as Figure 2 and Figure 5 . It shows that catalyst A-5 has the MFI topological structure and crystal grain morphology of TS-1 molecular sieve.

[0047] Aqueous-phase ammoximation of cyclohexanone: The reaction conditions are the same as those in Example 1, the catalyst is A-5, and the reaction results are shown in Table 1. Example 6

[0048] Catalyst preparation: Prepare an aqueous solution of a mixture of hydrochloric acid and aluminum chloride, with a hydrochloric acid content of 5% and an aluminum chloride content of 6%. Add 10 g of titanium silicate molecular sieve TS-1 to 80 g of the above aqueous solution, stir evenly, load it into a crystallization kettle with a Teflon liner, perform hydrothermal treatment at 100 °C for 48 h, and then obtain the intrinsic amphiphilic catalyst after cooling, filtering, washing, drying at 100 °C for 12 h, and calcining at 500 °C for 6 h. The catalyst number is A-6.

[0049] Aqueous-phase ammoximation of cyclohexanone: The reaction conditions are the same as those in Example 1, the catalyst is A-6, and the reaction results are shown in Table 1. Example 7

[0050] Catalyst preparation: Prepare an aqueous solution of a mixture of sulfuric acid and aluminum sulfate, with a sulfuric acid content of 1% and an aluminum sulfate content of 3%. Add 10 g of titanium silicate molecular sieve Ti-MWW to 50 g of the above aqueous solution, stir evenly, load it into a crystallization kettle with a Teflon liner, perform hydrothermal treatment at 100 °C for 24 h, and then obtain the intrinsic amphiphilic catalyst after cooling, filtering, washing, drying at 100 °C for 12 h, and calcining at 500 °C for 6 h. The catalyst number is A-7. The XRD pattern and SEM photo of the catalyst are as Figure 3 and Figure 6 . It shows that catalyst A-7 has the MWW topological structure and crystal grain morphology of Ti-MWW molecular sieve.

[0051] Aqueous-phase ammoximation of cyclohexanone: The reaction conditions are the same as those in Example 1, the catalyst is A-7, and the reaction results are shown in Table 1. Example 8

[0052] Catalyst Preparation: Prepare an aqueous solution by mixing hydrochloric acid and aluminum chloride, with the hydrochloric acid content being 3% and the aluminum chloride content being 5%. Add 10 g of titanium silicate molecular sieve Ti-MWW to 50 g of the above aqueous solution, stir evenly, load it into a crystallization kettle with a Teflon liner, perform hydrothermal treatment at 120 °C for 24 h, and then obtain the intrinsic amphiphilic catalyst after cooling, filtering, washing, drying at 100 °C for 12 h, and calcining at 500 °C for 6 h. The catalyst number is A-8.

[0053] Aqueous Phase Ammoximation of Cyclohexanone: The reaction conditions are the same as those in Example 1, the catalyst is A-8, and the reaction results are shown in Table 1. Example 9

[0054] Catalyst Preparation: The same as in Example 7.

[0055] Aqueous Phase Ammoximation of Methyl Ethyl Ketone: Add 1 g of catalyst, 81.6 g of ammonia water (concentration 5%), and 14.4 g of methyl ethyl ketone to the reaction kettle. Heat up to 65 °C under stirring conditions, dropwise add 27.2 g of hydrogen peroxide (concentration 30%). After the addition of hydrogen peroxide is completed, time for 1 h, add 50 g of ethanol to make the materials mix evenly, take samples, and perform chromatographic quantitative analysis on the conversion rate and selectivity of methyl ethyl ketone. The reaction results are shown in Table 1. Example 10

[0056] Catalyst Preparation: The same as in Example 1.

[0057] Aqueous Phase Ammoximation of Acetone: Add 1 g of catalyst, 122.4 g of ammonia water (concentration 5%), and 11.6 g of acetone to the reaction kettle. Heat up to 60 °C under stirring conditions, dropwise add 28.3 g of hydrogen peroxide (concentration 30%). After the addition of hydrogen peroxide is completed, time for 1 h, take samples, and perform chromatographic quantitative analysis on the conversion rate and selectivity of acetone. The reaction results are shown in Table 1. Comparative Example 1

[0058] Use the titanium silicate molecular sieve Ti-MOR (catalyst number D-1) without hydrothermal treatment in the aqueous phase ammoximation of cyclohexanone. The reaction conditions are the same as those in Example 1. Comparative Example 2

[0059] Catalyst Preparation: Prepare an aqueous solution of aluminum nitrate with an aluminum nitrate content of 8%. Add 10 g of titanium silicate molecular sieve Ti-MOR to 80 g of the above aqueous solution, stir evenly, load it into a crystallization kettle with a Teflon liner, perform hydrothermal treatment at 150 °C for 48 h, and then obtain the catalyst after cooling, filtering, washing, drying at 100 °C for 12 h, and calcining at 500 °C for 6 h. The catalyst number is D-2.

[0060] Aqueous-phase ammoximation of cyclohexanone: The reaction conditions were the same as those in Example 1, and the catalyst was D-2. The reaction results are shown in Table 1. Comparative Example 3

[0061] Catalyst preparation: An aqueous nitric acid solution was prepared with a nitric acid content of 5%. 10 g of titanium silicate molecular sieve Ti-MOR was added to 80 g of the above aqueous solution, stirred evenly, loaded into a crystallization kettle with a Teflon liner, hydrothermally treated at 150 °C for 48 h, and then obtained the catalyst after cooling, filtering, washing, drying at 100 °C for 12 h, and calcining at 500 °C for 6 h. The catalyst was numbered D-3.

[0062] Aqueous-phase ammoximation of cyclohexanone: The reaction conditions were the same as those in Example 1, and the catalyst was D-3. The reaction results are shown in Table 1. Comparative Example 4

[0063] Catalyst preparation: An aqueous solution mixed with sulfuric acid and aluminum sulfate was prepared, with a sulfuric acid content of 0.5% and an aluminum sulfate content of 1%. 10 g of titanium silicate molecular sieve TS-1 was added to 50 g of the above aqueous solution, stirred evenly, loaded into a crystallization kettle with a Teflon liner, hydrothermally treated at 100 °C for 60 h, and then obtained the catalyst after cooling, filtering, washing, drying at 100 °C for 12 h, and calcining at 500 °C for 6 h. The catalyst was numbered D-4.

[0064] Aqueous-phase ammoximation of cyclohexanone: The reaction conditions were the same as those in Example 1, and the catalyst was D-4. The reaction results are shown in Table 1.

[0065] Table 1 Aqueous-phase oximation performance of each catalyst

[0066] As can be seen from the above table, the intrinsic amphiphilic catalyst of the present invention exhibits excellent catalytic performance in the aqueous-phase ammoximation reaction of ketones.

Claims

1. An intrinsic amphiphilic catalyst, characterized in that, It is obtained by hydrothermally treating titanium silicalite molecular sieve with an aqueous solution, and the aqueous solution contains an acid and an aluminum salt corresponding to the acid.

2. The preparation method of the intrinsic amphiphilic catalyst according to claim 1, characterized in that, Using titanium silicalite molecular sieve as raw material, the titanium silicalite molecular sieve is hydrothermally treated with an aqueous solution, and after treatment, it is filtered, washed, dried, and calcined to obtain the intrinsic amphiphilic catalyst; the aqueous solution contains an acid and an aluminum salt corresponding to the acid.

3. The preparation method according to claim 2, wherein The titanium silicalite molecular sieve is selected from at least one of TS-1, Ti-MWW, and Ti-MOR.

4. The preparation method according to claim 2 or 3, characterized in that, The acid is selected from at least one of sulfuric acid, hydrochloric acid, and nitric acid; the aluminum salt corresponding to the acid is selected from at least one of aluminum sulfate, aluminum chloride, and aluminum nitrate.

5. The preparation method according to any one of claims 3 to 4, characterized in that, The solid-liquid mass ratio of the titanium silicalite molecular sieve to the aqueous solution is 1:3 to 10.

6. The preparation method according to any one of claims 3 to 5, characterized in that, In the aqueous solution, the mass concentration of the acid is 1% to 6%, and the mass concentration of the aluminum salt corresponding to the acid is 3% to 10%.

7. The preparation method according to any one of claims 3 to 6, characterized in that The treatment temperature of the hydrothermal treatment is 100 to 150 °C, and the treatment time is 24 to 48 h; and / or, the drying temperature is 80 to 120 °C, and the calcination temperature is 500 to 600 °C.

8. Application of the intrinsic amphiphilic catalyst according to claim 1 in the aqueous phase ammoximation reaction of ketones.

9. The application according to claim 8, wherein In the aqueous phase ammoximation reaction of ketones, the molar ratio of H2O2, ammonia to ketones is 1.01 to 1.30:1.10 to 1.90:1, the dosage of the intrinsic amphiphilic catalyst is 4% to 10% of the mass of the ketone, and the reaction temperature is 60 to 95 °C.

10. The application according to claim 8 or 9, characterized in that, The ketones are selected from at least one of methyl ethyl ketone, cyclohexanone, and acetone.

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