A composite catalyst based on SVR zeolite and its preparation method and application

Abstract

The invention discloses a composite catalyst based on SVR zeolite and its preparation method and application, the preparation method comprises the steps: after mixing a silicon source, an aluminum source, a structure directing agent and water, an initial gel is obtained; after the initial gel is subjected to a hydrothermal crystallization reaction under the conditions of a first preset temperature and stirring, an SVR zeolite is obtained; after the SVR zeolite is mixed with a transition metal salt solution, the first preset time is stirred, and after centrifugation, the obtained solid is calcined at a second preset temperature for a second preset time to obtain a composite catalyst based on SVR zeolite; the structure directing agent is hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) hydroxide. The composite catalyst based on SVR zeolite prepared in the present invention provides an active site for catalyzing the hydroxylation reaction of phenol, has good catalytic performance, and catalyzes the hydroxylation of phenol to prepare diphenol with high selectivity and yield, and has good industrial application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of zeolite materials, and in particular to a composite catalyst based on SVR zeolite and a preparation method and application thereof. Background Art

[0002] The yield and selectivity of phenol hydroxylation to diphenol reported in the literature are not ideal. For example, when titanium silicalite molecular sieve is used to catalyze the hydroxylation of phenol, the yield of diphenol is 7.6% and the selectivity is 92.3% after 2 hours of reaction at 80°C with acetone as solvent (see reference 1 below); when copper-containing mesoporous silica with hierarchical porous structure is used to catalyze the hydroxylation of phenol, the yield of diphenol is 26% and the selectivity is up to 64% after 5 hours of reaction at 70°C with water as solvent (see reference 2 below).

[0003] SVR (Zeolite Three-letter Structure Code: SVR) zeolite is a high-silicon zeolite with three-dimensional ten-membered ring channels. Its zigzag channels are connected to other channels through relatively straight channels. The dimensions of the ten-membered ring channels parallel to the

[100] ,

[010] and

[001] crystal directions are and SVR zeolite has shown good industrial practical value in a series of chemical and chemical catalytic reactions (such as hydrocarbon conversion reaction, acylation reaction, etc.). However, there is no report on the application of SVR zeolite-based catalyst in the field of phenol hydroxylation to prepare diphenol. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a composite catalyst based on SVR zeolite and a preparation method and application thereof, aiming to provide a catalyst that can catalyze phenol to produce diphenol with high yield and selectivity.

[0005] The technical solution of the present invention is as follows:

[0006] The first aspect of the present invention provides a method for preparing a composite catalyst based on SVR zeolite, which comprises the steps of:

[0007] After mixing the silicon source, the aluminum source, the structure directing agent and water, an initial gel is obtained;

[0008] The initial gel is subjected to a hydrothermal crystallization reaction at a first preset temperature and under stirring conditions to obtain SVR zeolite;

[0009] After mixing the SVR zeolite and the transition metal salt solution, stirring for a first preset time, centrifuging, and calcining the obtained solid at a second preset temperature for a second preset time to obtain the SVR zeolite-based composite catalyst;

[0010] The structure directing agent is hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) hydroxide.

[0011] Optionally, the silicon source includes at least one of tetraethyl orthosilicate, colloidal silicon dioxide, and fumed silicon dioxide;

[0012] The aluminum source includes at least one of sodium aluminate, aluminum nitrate, and aluminum chloride;

[0013] The transition metal salt solution is prepared by dissolving a transition metal salt in water, wherein the transition metal salt comprises at least one of anhydrous ferric chloride, ferric nitrate nonahydrate, copper nitrate hexahydrate, and cobalt chloride hexahydrate.

[0014] Optionally, SiO2, AlO 1.5 , R and H2O, the molar ratio of the silicon source, aluminum source, structure directing agent and water satisfies:

[0015] SiO2:AlO 1.5 :R:H2O=(10~80):(0.1~5):(2~12):(1000~1800).

[0016] Optionally, the initial gel is subjected to a hydrothermal crystallization reaction at 100-160° C. and stirring at 10-50 rpm for 12-20 days to obtain SVR zeolite.

[0017] Optionally, the concentration of the transition metal salt in the transition metal salt solution is 0.005 to 0.1 mol / L;

[0018] The ratio of the SVR zeolite to the transition metal salt solution is (0.01-0.16) g:2 mL.

[0019] Optionally, the first preset time is 8 to 32 hours.

[0020] Optionally, the second preset temperature is 300-600° C., and the second preset time is 1-6 hours.

[0021] Optionally, the preparation method of hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) hydroxide comprises the following steps:

[0022] Add N-methylpyrrolidine and 1,6-dibromohexane to an organic solvent and stir at room temperature for 1 to 5 days to obtain hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide;

[0023] Hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide and silver oxide are added to water and reacted for 1 to 12 hours to obtain hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) hydroxide;

[0024] The molar ratio of the hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide to silver oxide is (0.5-3):1.

[0025] The second aspect of the present invention provides a composite catalyst based on SVR zeolite, wherein the composite catalyst based on SVR zeolite is prepared by the preparation method of the present invention as described above.

[0026] The third aspect of the present invention provides use of the SVR zeolite-based composite catalyst as described above in catalyzing the preparation of diphenol from phenol.

[0027] Beneficial effects: The SVR zeolite-based composite catalyst prepared in the present invention is an SVR zeolite loaded with transition metal atoms, which provides active sites for catalyzing the hydroxylation reaction of phenol and has good catalytic performance. It has high selectivity (up to 99%) and yield (up to 32%) for catalyzing the hydroxylation of phenol to prepare diphenol, and has good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the standard curve of catechol gas chromatography internal standard method.

[0029] Figure 2 This is the standard curve of hydroquinone gas chromatography internal standard method.

[0030] Figure 3 This is the H NMR spectrum of hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide.

[0031] Figure 4 This is the carbon NMR spectrum of hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide.

[0032] Figure 5 These are the XRD diagrams of Fe-SVR-1 prepared in Example 1, Fe-SVR-3 prepared in Example 2, Fe-SVR-5 prepared in Example 3, and SVR-calc prepared in Comparative Example 1.

[0033] Figure 6 This is the SEM image of Fe-SVR-1 prepared in Example 1.

[0034] Figure 7 This is the EDS element surface scanning image of Fe-SVR-1 prepared in Example 1.

[0035] Figure 8 This is the SEM image of Fe-SVR-3 prepared in Example 2.

[0036] Fig. 9 This is the EDS element surface scanning image of Fe-SVR-3 prepared in Example 2.

[0037] Fig.10 This is the SEM image of Fe-SVR-5 prepared in Example 3.

[0038] Fig.11 This is the EDS element surface scanning image of Fe-SVR-5 prepared in Example 3.

[0039] Fig.12 This is the SEM image of SVR-calc prepared in Comparative Example 1. DETAILED DESCRIPTION

[0040] The present invention provides a composite catalyst based on SVR zeolite and a preparation method and application thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0042] The embodiment of the present invention provides a method for preparing a composite catalyst based on SVR zeolite, which comprises the steps of:

[0043] S1, mixing a silicon source, an aluminum source, a structure directing agent and water to obtain an initial gel; the structure directing agent is hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) hydroxide;

[0044] S2, subjecting the initial gel to a hydrothermal crystallization reaction at a first preset temperature and stirring conditions to obtain SVR zeolite;

[0045] S3. After mixing the SVR zeolite and the transition metal salt solution, stirring for a first preset time, centrifuging, and calcining the obtained solid at a second preset temperature for a second preset time to obtain the SVR zeolite-based composite catalyst.

[0046] The SVR zeolite-based composite catalyst prepared in the embodiment of the present invention is an SVR zeolite loaded with transition metal atoms, which provides active sites for catalyzing the hydroxylation reaction of phenol and has good catalytic performance. It has high selectivity (up to 99%) and yield (up to 32%) for catalyzing the hydroxylation of phenol to prepare diphenol, and has good industrial application prospects.

[0047] Since SVR zeolite has a special framework structure, that is, a zeolite framework containing multi-atomic complex asymmetric structural units and having ordered silanol defects, hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) hydroxide is used as a structure directing agent.

[0048] In step S1, in some embodiments, the silicon source includes at least one of tetraethyl orthosilicate, colloidal silica, and fumed silica, but is not limited thereto.

[0049] In some embodiments, the aluminum source includes at least one of sodium aluminate, aluminum nitrate, and aluminum chloride, but is not limited thereto.

[0050] In some embodiments, the water is deionized water.

[0051] In some embodiments, SiO2, AlO 1.5 The molar ratio of the silicon source, the aluminum source, the structure directing agent and the water satisfies: SiO2:AlO 1.5 :R:H2O=(10~80):(0.1~5):(2~12):(1000~1800).

[0052] In some specific embodiments, SiO2, AlO 1.5 The molar ratio of the silicon source, the aluminum source, the structure directing agent and the water satisfies: SiO2 / AlO 1.5 =10-100, SiO2 / R=1-10, SiO2 / H2O=0.006-0.08; R is a structure directing agent. That is, the source, aluminum source, structure directing agent and water are SiO2, AlO 1.5 , R and H2O, satisfying the above molar ratio. For example, SiO2 / AlO 1.5 =10, 20, 30, 40, 50, 60, 70, 80, 90 or 100, etc.; SiO2 / R=1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, etc.; SiO2 / H2O=0.006, 0.008, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08, etc.

[0053] In some embodiments, the method for preparing hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) hydroxide comprises the following steps:

[0054] Add N-methylpyrrolidine and 1,6-dibromohexane to an organic solvent (acetone), and stir at room temperature for 1 to 5 days to obtain hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide;

[0055] Hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide and silver oxide are added to water and reacted for 1 to 12 hours to obtain hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) hydroxide;

[0056] The molar ratio of hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide to silver oxide is (0.5-3): 1. For example, the molar ratio of hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide to silver oxide is 0.5:1, 1:1, 2:1 or 3:1.

[0057] In some embodiments, the mass ratio of N-methylpyrrolidine to 1,6-dibromohexane is (1-5):(2-10). For example, the mass ratio of N-methylpyrrolidine to 1,6-dibromohexane can be 1:2, 2.5:2, 3:2, 5:2, 1:10, 2.5:10, 3:10 or 5:10, etc.

[0058] In some specific embodiments, the mass ratio of N-methylpyrrolidine to 1,6-dibromohexane is (1-5):(2.9-2.95).

[0059] In step S2, in some embodiments, the initial gel is subjected to a hydrothermal crystallization reaction at 100-160°C (for example, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C or 160°C, etc.) and stirring at 10-50rpm (for example, 10rpm, 20rpm, 30rpm, 40rpm or 50rpm, etc.) for 12-20 days (for example, 12 days, 13 days, 14 days, 15 days, 16 days, 17 days, 18 days, 19 days or 20 days, etc.) to obtain SVR zeolite.

[0060] In step S3, in some embodiments, the transition metal salt solution is prepared by dissolving a transition metal salt in water, and the transition metal salt includes at least one of anhydrous ferric chloride, ferric nitrate nonahydrate, copper nitrate hexahydrate, and cobalt chloride hexahydrate, but is not limited thereto.

[0061] In some embodiments, the concentration of the transition metal salt in the transition metal salt solution is 0.005-0.1 mol / L. That is, the ratio of the transition metal salt to water is (0.005-0.1) mol:1L.

[0062] In some embodiments, the ratio of the SVR zeolite to the transition metal salt solution is (0.01-0.16) g:2 mL. For example, the ratio of the SVR zeolite to the transition metal salt solution is 0.01 g:2 mL, 0.01 g:2 mL, 0.02 g:2 mL, 0.05 g:2 mL, 0.1 g:2 mL, 0.015 g:2 mL or 0.16 g:2 mL, etc.

[0063] In some embodiments, the first preset time is 8 to 32 hours. For example, the first preset time can be 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 20 hours, 25 hours, 30 hours or 32 hours.

[0064] In specific implementation, when SVR zeolite is mixed with transition metal salt solution, it can be done in two steps, that is, firstly SVR zeolite is mixed with half of transition metal salt solution, stirred for 0.5 times of the first preset time (i.e. 4 to 16 hours), centrifuged and dried, and the dried solid is mixed with the other half of transition metal salt solution, stirred for 0.5 times of the first preset time (4 to 16 hours), centrifuged and dried.

[0065] In some embodiments, the second preset temperature is 300-600°C (for example, 300°C, 400°C, 500°C or 600°C, etc.), and the second preset time is 1-6h (for example, 1h, 2h, 3h, 4h, 5h or 6h, etc.).

[0066] The embodiment of the present invention also provides a composite catalyst based on SVR zeolite, wherein the composite catalyst based on SVR zeolite is prepared by the preparation method of the present invention as described above, and the composite catalyst based on SVR zeolite includes SVR zeolite and transition metal atoms (iron atoms, copper atoms, cobalt atoms, etc.) loaded in the pores of the SVR zeolite. The composite catalyst based on SVR zeolite provides active sites for catalyzing the hydroxylation reaction of phenol, has good catalytic performance, and catalyzes the hydroxylation of phenol to prepare diphenol with high selectivity (up to 99%) and yield (up to 32%), and has good industrial application prospects.

[0067] The present invention also provides an application of the composite catalyst based on SVR zeolite as described above in the present invention to catalyze phenol to prepare diphenol. Specifically, the diphenol includes o-diphenol and p-diphenol.

[0068] In some embodiments, in the step of preparing diphenol, phenol is used as a reaction substrate, acetonitrile and water are used as solvents, hydrogen peroxide is used as an oxidant, and acetic acid is used as an additive, and diphenol is prepared under the action of a composite catalyst based on SVR zeolite.

[0069] The following describes it in detail through specific embodiments.

[0070] Unless otherwise specified, the raw materials and solvents used in the following examples can be purchased from commercial sources.

[0071] The main test instruments and analysis methods used in the following examples are as follows:

[0072] Powder X-ray diffraction (XRD) phase analysis was performed using a SmartLab diffractometer from Rigaku Corporation [Cu target, Kα radiation source (λ=0.15418 nm), voltage of 40 kV, current of 100 mA].

[0073] The catalytic reaction was qualitatively analyzed using GC-MS from Thermo Fisher Scientific Trace ISQLT.

[0074] The catalytic reaction was quantitatively analyzed using the FL 9790 Plus gas chromatography workstation (column information: 30 m × 320 μm × 0.5 μm) produced by Zhejiang Fuli Analytical Instrument Co., Ltd.

[0075] Gas chromatography internal standard method:

[0076] (1) Preparation of standard solution and internal standard solution:

[0077] Take a certain amount of phenol, catechol and hydroquinone respectively, accurately record the mass of each sample, dissolve them in ethyl acetate and make up to the volume in a 25mL volumetric flask to obtain a series of standard solutions.

[0078] Weigh a certain amount of tetradecane, dissolve it in ethyl acetate and make up to the volume in a 50 mL volumetric flask after accurately recording the mass to obtain an internal standard solution.

[0079] (2) Preparation of a series of standard mixed solutions:

[0080] Accurately pipette different gradient volumes of standard solution, add the same volume of internal standard solution and dilute to the same volume with ethyl acetate. Detect the prepared series of standard mixed solutions on FL 9790 Plus gas chromatograph, record the retention time and peak area. The mass ratio of standard mixture to internal standard (m i / m s ) is the horizontal axis, and the peak area ratio of the standard mixture to the internal standard (A i / A s ) as the vertical axis to make a standard curve (such as Figure 1 and 2 The linear equation is shown in Table 1. The reciprocal of the slope of the linear equation is the correction factor (f is ).

[0081] Table 1. Standard equations and correction factors for catechol and hydroquinone

[0082]

[0083] (3) Determination of sample content in reaction solution:

[0084] Take all the reaction solution and add the same volume of internal standard as that used in preparing the standard mixed solution, make up to volume with ethyl acetate, detect on FL 9790 Plus gas chromatograph, and record the retention time and peak area.

[0085] Sample content calculation formula:

[0086]

[0087] Wherein, Wi: sample mass content in the reaction solution;

[0088] m: mass of reaction solution;

[0089] m s : mass of internal standard;

[0090] A s : internal standard peak area;

[0091] A i : The peak area of ​​the corresponding substance in the reaction solution;

[0092] f is : Correction factor, which is the reciprocal of the slope.

[0093] The calculation formula of the yield and selectivity of diphenol is as follows:

[0094]

[0095]

[0096] Y 二苯酚 : represents the yield of catechol plus hydroquinone; n 邻苯二酚 : represents the amount of catechol, the peak area is detected on FL9790Plus gas chromatograph, and the amount of substance is calculated by the gas chromatography internal standard method; n 对苯二酚 : represents the amount of hydroquinone, the peak area is detected on FL 9790Plus gas chromatograph, and the amount of hydroquinone is calculated by the gas chromatography internal standard method; n 苯酚 : represents the amount of phenol initially added: S 二苯酚 : represents the selectivity of catechol plus hydroquinone: n 所有产物: represents the amount of substance of all products and each peak area is detected on FL 9790Plus gas chromatograph, and the amount of each substance is calculated by the formula of gas chromatography internal standard method.

[0097] Example 1

[0098] This embodiment provides a method for preparing a composite catalyst based on SVR zeolite, comprising the following steps:

[0099] (1) 3.5 g of N-methylpyrrolidine was dissolved in 50 mL of acetone, and then 4.9 g of 1,6-dibromohexane was added. The mixture was stirred at room temperature for 3 days, and then the solid product was recovered by filtration, washed with ether and dried to obtain hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide. Its H NMR spectrum data is: 1 HNMR (400MHz, DMSO-d6) δ3.54-3.40 (m, 8H), 3.32 (dd, J=8.0, 4.2Hz, 4H), 3.00 (s, 6H), 2.08 (q, J=3.6, 3.2Hz, 8H), 1.72 (s, 4H), 1.37-1.30 (m, 4H); its H NMR spectrum is as follows Figure 3 As shown (there are 6 signals). Its carbon NMR spectrum data is 13 CNMR (400MHz, DMSO-d6) 63.41ppm (1, 4-C), 62.81ppm (6-C), 47.49ppm (5-C), 25.43ppm (8-C), 22.75ppm (7-C), 21.08ppm (2, 3-C); its carbon nuclear magnetic resonance spectrum is as follows Figure 4 shown.

[0100] (2) After adding an appropriate amount of water to dissolve hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide, 1.05 equivalents of silver oxide (the molar ratio of silver oxide to hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide is 1.05:1) is added and reacted for 4 hours to fully convert it into a hydroxide form to obtain hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) hydroxide, which is a structure directing agent.

[0101] (3) SiO2, AlO 1.5 , R and H2O, colloidal SiO2, Al(NO3)3, hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) hydroxide and deionized water were mixed at a ratio of SiO2 / AlO 1.5 =40, R / SiO2=0.15, H2O / SiO2=30 in a molar ratio and stirred for 30 minutes to prepare an initial gel;

[0102] (4) The obtained initial gel was placed in a 25 mL crystallization kettle and subjected to hydrothermal crystallization reaction at 160° C. at a rotation speed of 25 rpm for 15 days. After cooling, the reaction solution was centrifuged, washed, dried, and analyzed by XRD, which confirmed that it was a pure phase SVR zeolite.

[0103] (5) Anhydrous ferric chloride was added to water to prepare a solution A containing 0.01 mol / L FeCl3; 1 g of SVR zeolite was stirred and mixed with 20 mL of solution A to obtain solution B. After stirring for 12 h (i.e., room temperature immersion), solution B was centrifuged and washed with water until neutral and then dried overnight. Then, the solid was stirred and mixed with 20 mL of solution A to obtain solution C. After stirring for 12 h (i.e., room temperature immersion), solution C was centrifuged and washed with water until neutral and then dried overnight. Subsequently, it was calcined at 350°C for 2 h to obtain a composite catalyst based on SVR zeolite with a mass of 0.9469 g. The solid sample was pink. It was numbered as Fe-SVR-1.

[0104] XRD analysis shows that the loading of iron atoms has almost no effect on the topological structure of SVR zeolite. Its XRD data are shown in Table 1 and its XRD pattern is shown in Figure 5 Its SEM image is shown in Figure 6 As shown, its EDS (energy dispersive spectrometer) element surface scanning diagram ( Figure 6 The area corresponding to the small picture in the upper right corner is scanned) Figure 7 As shown, it is confirmed that the transition metal element Fe exists and is dispersed relatively evenly.

[0105] Table 2. XRD results of Fe-SVR-1

[0106]

[0107]

[0108] Example 2

[0109] This embodiment provides a method for preparing a composite catalyst based on SVR zeolite, which differs from Embodiment 1 only in that:

[0110] In step (5), anhydrous ferric chloride is added to water to prepare a solution A containing 0.03 mol / L FeCl3; finally, a composite catalyst based on SVR zeolite with a mass of 0.9469 g is obtained, and its solid sample is pink in color. It is numbered as Fe-SVR-3.

[0111] XRD analysis shows that the loading of iron atoms has almost no effect on the topological structure of SVR zeolite. Figure 5 Its SEM image is shown in Figure 8 As shown, its EDS element surface scan diagram ( Figure 8 Scan the area corresponding to the small picture in the upper right corner) Fig. 9 As shown, it is confirmed that the transition metal element Fe exists and is dispersed relatively evenly.

[0112] Example 3

[0113] This embodiment provides a method for preparing a composite catalyst based on SVR zeolite, which differs from Embodiment 1 only in that:

[0114] In step (5), anhydrous ferric chloride is added to water to prepare a solution A containing 0.05 mol / LFeCl3 (molar content); finally, a composite catalyst based on SVR zeolite with a mass of 0.9599 g is obtained, and its solid sample is pink but darker than that of Example 2. It is numbered as Fe-SVR-5.

[0115] XRD analysis shows that the loading of iron atoms has almost no effect on the topological structure of SVR zeolite. Figure 5 Its SEM image is shown in Fig.10 As shown, its EDS element surface scan diagram ( Fig.10 Scan the area corresponding to the small picture in the upper right corner) Fig.11 shown.

[0116] Comparative Example 1

[0117] This comparative example 1 provides a method for preparing a composite catalyst based on SVR zeolite, which differs from Example 1 only in that step (5) is not performed, and a pure phase SVR zeolite is obtained, which is a white solid and is numbered as SVR-calc. Its SEM image is as follows: Fig.12 shown.

[0118] Application Example 1

[0119] 0.1 g of Fe-SVR-1 in Example 1 was used in the hydroxylation reaction of phenol. Specifically, 0.1 g of Fe-SVR-1 in Example 1, 5 mmol of phenol (as a substrate), 2 mL of acetonitrile and water (both as solvents), 10 mmol of hydrogen peroxide (as an oxidant) and 10 mmol of acetic acid (as an additive) were added to a solvent storage bottle and mixed, and reacted at 80° C. for 2 hours. The reaction liquid was centrifuged for solid-liquid separation, and the upper layer of liquid was taken and the components in the reaction liquid were determined by GC-MS, confirming that the products obtained by the reaction were catechol and hydroquinone. The components in the reaction liquid were quantitatively analyzed by FL 9790 Plus gas chromatography, and then the correction factor obtained by the gas chromatography internal standard method was combined with the above formula to calculate that the yield of diphenol was 32% and the selectivity was 99%.

[0120] Application Example 2

[0121] 0.1 g of Fe-SVR-3 in Example 2 was used in the hydroxylation reaction of phenol. Specifically, 0.1 g of Fe-SVR-1 in Example 1, 5 mmol of phenol (as substrate), 2 mL of acetonitrile and water (both as solvents), 10 mmol of hydrogen peroxide (as oxidant) and 10 mmol of acetic acid (as additive) were added to a solvent storage bottle and mixed, and reacted at 80° C. for 2 hours, and then the reaction liquid was centrifuged for solid-liquid separation, and the upper layer of liquid was taken and the components in the reaction liquid were determined by GC-MS, confirming that the products obtained by the reaction were catechol and hydroquinone, and the components in the reaction liquid were quantitatively analyzed by FL 9790 Plus gas chromatography, and then the correction factor obtained by gas chromatography internal standard method combined with the above formula was calculated to obtain a yield of diphenol of 19% and a selectivity of 99%.

[0122] Application Example 3

[0123] 0.1 g of Fe-SVR-5 in Example 3 was used in the hydroxylation reaction of phenol. Specifically, 0.1 g of Fe-SVR-1 in Example 1, 5 mmol of phenol (as substrate), 2 mL of acetonitrile and water (both as solvents), 10 mmol of hydrogen peroxide (as oxidant) and 10 mmol of acetic acid (as additive) were added to a solvent storage bottle and mixed, and reacted at 80° C. for 2 hours, and then the reaction liquid was centrifuged for solid-liquid separation, and the upper layer of liquid was taken and the components in the reaction liquid were determined by GC-MS, confirming that the products obtained by the reaction were catechol and hydroquinone, and the components in the reaction liquid were quantitatively analyzed by FL 9790 Plus gas chromatography, and then the correction factor obtained by gas chromatography internal standard method was combined with the above formula to calculate the yield of diphenol to be 8% and the selectivity to be 99%.

[0124] As the iron atom content in the SVR zeolite-based composite catalyst increases, the yield of diphenol decreases. The possible reason is that too many iron atoms block the zeolite pores, resulting in a decrease in yield.

[0125] Application Comparative Example 1

[0126] 0.1 g of SVR-calc in Comparative Example 1 was used in the hydroxylation reaction of phenol. Specifically, 0.1 g of SVR-calc in Comparative Example 1, 5 mmol of phenol (as a substrate), 2 mL of acetonitrile and water (both as solvents), 10 mmol of hydrogen peroxide (as an oxidant) and 10 mmol of acetic acid (as an additive) were added to a solvent storage bottle and mixed, and reacted at 80° C. for 2 hours, and then the reaction liquid was centrifuged for solid-liquid separation, and the upper layer of liquid was taken and the components in the reaction liquid were determined by GC-MS, and no catechol and hydroquinone were detected. The components in the reaction liquid were quantitatively analyzed by FL 9790 Plus gas chromatography, and then the correction factor obtained by the gas chromatography internal standard method was combined with the formula to calculate the yield of diphenol to be 0%, indicating that the reaction did not produce catechol and hydroquinone.

[0127] The catalytic effects of the catalysts currently reported for phenol hydroxylation are summarized in Table 2 below.

[0128] Table 2. Catalytic effects of currently reported catalysts for phenol hydroxylation

[0129]

[0130]

[0131] From the above results, it can be seen that the iron-containing SVR zeolite prepared by the preparation method provided by the present invention as a catalyst has higher yield and selectivity in the phenol hydroxylation reaction than the iron-free SVR zeolite as a catalyst and the existing catalyst, showing good catalytic performance and having good industrial prospects.

[0132] Reference information is as follows:

[0133] 1. Microporous and Mesoporous Materials2022, 336, 111884.

[0134] 2. Chinese Journal of Catalysis 2010, 31(4), 386-393.

[0135] 3. Journal of Chemistry 2021, 2021, 1-10.

[0136] 4. Microporous and Mesoporous Materials 2018, 268, 84-87.

[0137] 5. ChemistrySelect2019, 4(5), 1618-1626.

[0138] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a composite catalyst based on SVR zeolite, characterized in that: Includes steps: After mixing the silicon source, the aluminum source, the structure directing agent and water, an initial gel is obtained; The initial gel is subjected to a hydrothermal crystallization reaction at a first preset temperature and under stirring conditions to obtain SVR zeolite; After mixing the SVR zeolite and the transition metal salt solution, stirring for a first preset time, centrifuging, and calcining the obtained solid at a second preset temperature for a second preset time to obtain the SVR zeolite-based composite catalyst; The structure directing agent is hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) hydroxide; The transition metal salt solution is prepared by dissolving a transition metal salt in water, wherein the transition metal salt comprises at least one of anhydrous ferric chloride, ferric nitrate nonahydrate, copper nitrate hexahydrate, and cobalt chloride hexahydrate.

2. The preparation method according to claim 1, characterized in that: The silicon source includes at least one of tetraethyl orthosilicate, colloidal silicon dioxide, and fumed silicon dioxide; The aluminum source includes at least one of sodium aluminate, aluminum nitrate and aluminum chloride.

3. The preparation method according to claim 1, characterized in that: SiO2, AlO 1.5 , R and H2O, the molar ratio of the silicon source, aluminum source, structure directing agent and water satisfies: SiO2:AlO 1.5 :R:H2O=(10~80):(0.1~5):(2~12):(1000~1800)。 4. The preparation method according to claim 1, characterized in that: The initial gel is subjected to a hydrothermal crystallization reaction at 100-160° C. and stirring at 10-50 rpm for 12-20 days to obtain SVR zeolite.

5. The preparation method according to claim 2, characterized in that: The concentration of the transition metal salt in the transition metal salt solution is 0.005 to 0.1 mol / L; The ratio of the SVR zeolite to the transition metal salt solution is (0.01-0.16) g:2 mL.

6. The preparation method according to claim 1, characterized in that: The first preset time is 8 to 32 hours.

7. The preparation method according to claim 1, characterized in that: The second preset temperature is 300-600° C., and the second preset time is 1-6 hours.

8. The preparation method according to claim 1, characterized in that: The preparation method of the hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) hydroxide comprises the following steps: Add N-methylpyrrolidine and 1,6-dibromohexane to an organic solvent and stir at room temperature for 1 to 5 days to obtain hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide; Hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide and silver oxide are added to water and reacted for 1 to 12 hours to obtain hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) hydroxide; The molar ratio of the hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium) bromide to silver oxide is (0.5-3):

1.

9. A composite catalyst based on SVR zeolite, characterized in that: The SVR zeolite-based composite catalyst is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the SVR zeolite-based composite catalyst according to claim 9 in catalyzing the preparation of catechol and hydroquinone from phenol.

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