A hierarchical porous titanium silicate molecular sieve TS-1 and its synthesis method

Abstract

This invention discloses a hierarchical porous titanium-silicon molecular sieve TS-1 and its synthesis method. The method includes the following steps: S1: Raw materials containing silicon source, titanium source, quaternary ammonium base template agent and water are mixed to obtain an initial gel mixture A, which is then heated and crystallized under sealed conditions to obtain a preform solution I; S2: Raw materials containing silicon source, base source R, water, titanium source and protective agent S are mixed to obtain a gel mixture II; S3: The preform solution I from step S1 and the gel mixture II from step S2 are mixed to obtain a gel mixture III, which is then heated and crystallized under sealed conditions to obtain the hierarchical porous titanium-silicon molecular sieve TS-1. This invention provides a synthesis method that allows for the direct synthesis of TS-1 single-crystal molecular sieve with a meso-microporous hierarchical structure using only a small amount of microporous template agent, assisted by a high-activity preform solution containing ultra-large specific surface area preform particles.

Description

Technical Field

[0001] This invention belongs to the field of molecular sieve technology, and particularly relates to a hierarchical porous titanium-silicon molecular sieve TS-1 and its synthesis method. Background Technology

[0002] Since its first synthesis in 1983, titanium silicate zeolite (TS-1) has been widely used in the preparation of fine chemicals due to its excellent catalytic performance in clean reaction systems using hydrogen peroxide as an oxidant (such as olefin epoxidation and phenol hydroxylation). However, the high synthesis cost of TS-1 zeolite has been limited by the availability of raw materials, thus restricting its large-scale application. Furthermore, the relatively small pore size of traditional TS-1 zeolite also limits its catalytic conversion of large molecular reactants.

[0003] The main reason for the high cost of TS-1 zeolite synthesis is that it requires the use of large amounts of expensive organic template agent tetrapropylammonium hydroxide (TPAOH), as well as organosilicon source tetraethyl orthosilicate (TEOS) and organotitanium source tetrabutyl titanate (TBOT).

[0004] On the other hand, existing technologies disclose methods for synthesizing hierarchical TS-1 molecular sieves by introducing mesoporous or macroporous pore-forming agents into the TS-1 zeolite synthesis system. However, these mesoporous pore-forming agents typically have complex structures and high costs. Moreover, some of these pore-forming agents require complex synthesis processes, and they usually need to be calcined to remove them during the use of the molecular sieves, which also causes environmental pollution. In addition to introducing pore-forming agents, increasing the number of seed crystals can be used to synthesize nano-TS-1 molecular sieves, but solid-liquid separation of ultrafine nano-molecular sieves is usually quite difficult. Summary of the Invention

[0005] In view of this, the present invention provides a hierarchical porous titanium-silicon molecular sieve TS-1 and its synthesis method, the main purpose of which is to solve the technical problems of high cost, complex operation and environmental unfriendliness of the synthesis method of the hierarchical porous structure of titanium-silicon molecular sieve TS-1.

[0006] On one hand, the present invention provides a method for synthesizing hierarchical porous titanium silicate molecular sieve TS-1, the method comprising the following steps:

[0007] S1: Raw materials containing silicon source, titanium source, quaternary ammonium base template agent and water are mixed to obtain initial gel mixture A. The initial gel mixture A is heated and crystallized under closed conditions to obtain crystal blank solution I.

[0008] S2: Raw materials containing silicon source, alkali source R, water, titanium source and protective agent S are mixed to obtain gel mixture II;

[0009] S3: The preform solution I in step S1 and the gel mixture II in step S2 are mixed to obtain gel mixture III. The gel mixture III is heated and crystallized under sealed conditions to obtain the hierarchical porous titanium silicon molecular sieve TS-1.

[0010] This invention provides a method for synthesizing a multi-level porous titanium-silicon molecular sieve, TS-1. This method uses only a small amount of microporous template agent during the synthesis of the titanium-silicon-based preform solution, without using a hard template agent. Furthermore, the amount of microporous template agent used is only 1 / 10 to 1 / 20 of that used in other conventional methods. This solves the problems of high cost and environmental pollution caused by the high price and toxicity of small-molecule microporous organic template agents and mesoporous pore-forming agents. Simultaneously, the product has a high framework Ti content and does not contain non-framework Ti or TiO2 species.

[0011] Optionally, in step S1, the molar ratio of the silicon source, the titanium source, the quaternary ammonium base template agent, and the water in the initial gel mixture A is:

[0012] Template agent: SiO2 = 0.10~0.50:1;

[0013] TiO2:SiO2=0.02~0.05:1;

[0014] H2O:SiO2 = 4~20:1;

[0015] Wherein, the number of moles of the silicon source is calculated as the number of moles of SiO2, the number of moles of the titanium source is calculated as the number of moles of TiO2, the number of moles of the template agent is calculated as the number of moles of quaternary ammonium base, and the number of moles of water is calculated as the number of moles of H2O.

[0016] Optionally, the molar ratio of template agent to SiO2 in the initial gel mixture A is selected from any value or a range between 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, and 0.50.

[0017] Optionally, in the initial gel mixture A,

[0018] The preferred molar ratio of template agent to SiO2 is 0.15–0.45;

[0019] The preferred molar ratio of template agent to SiO2 is 0.20–0.40;

[0020] The preferred molar ratio of TiO2 to SiO2 is 0.03 to 0.05:1;

[0021] The preferred molar ratio of H2O to SiO2 is 6 to 18.

[0022] Optionally, the molar ratio of TiO2 to SiO2 in the initial gel mixture A is selected from any value of 0.02, 0.03, 0.04, 0.05 or a range between any two.

[0023] Optionally, the molar ratio of H2O to SiO2 in the initial gel mixture A is selected from any value of 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or a range between any two.

[0024] Optionally, in step S2, the molar ratio of the silicon source, the titanium source, the alkali source R, the protective agent S, and the water in the gel mixture II is:

[0025] SiO2: TiO2: R: S: H2O=1: (0.02~0.10): (0.02~0.20): (0.02~

[0026] 0.2): (6~30);

[0027] Wherein, the number of moles of the silicon source is calculated as the number of moles of SiO2, the number of moles of the titanium source is calculated as the number of moles of TiO2, the number of moles of R is calculated as the number of moles of the alkali source R, the number of S is calculated as the number of moles of the protective agent S, and the number of moles of water is calculated as the number of moles of H2O.

[0028] Optionally, in step S2, the molar ratio of the silicon source, the titanium source, the alkali source R, the protective agent S, and the water in the gel mixture II is:

[0029] SiO2: TiO2: R: S: H2O=1: (0.02~0.10): (0.02~0.20): (0.02~

[0030] 0.20): (10~40).

[0031] Optionally, in step S2, in the gel mixture II,

[0032] R: SiO2 = 0.02~0.15;

[0033] H2O:SiO2 = 12~20;

[0034] TiO2:SiO2 = 0.02~0.05;

[0035] S: SiO2 = 0.02~0.12.

[0036] Optionally, the gel mixture II in step S2 is obtained by mixing the initial gel mixture B and the initial gel mixture C;

[0037] The initial gel mixture B is obtained by mixing a silicon source, an alkali source R, and water; the molar ratio of each component in the initial gel mixture B is:

[0038] R:SiO2 = 0 to 0.20:1;

[0039] H2O:SiO2 = 6~30:1;

[0040] The initial gel mixture C is obtained by mixing a titanium source and a protective agent S; the molar ratio of each component in the initial gel mixture C is:

[0041] S:TiO2 = 1~5:

[0042] Wherein, the number of moles of the silicon source is calculated as the number of moles of SiO2, the number of moles of the titanium source is calculated as the number of moles of TiO2, the number of moles of the alkali source R is calculated as the number of moles of R, the number of moles of the protective agent S is calculated as the number of moles of S, and the number of moles of water is calculated as the number of moles of H2O.

[0043] Optionally, in the initial gel mixture B, the molar ratio of R:SiO2 is selected from any value or a range between 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.12, 0.14, 0.16, 0.18, and 0.20.

[0044] In the initial gel mixture B, the molar ratio of H2O:SiO2 is selected from any value or a range between any two of 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30.

[0045] Optionally, in the initial gel mixture C, the molar ratio of S:TiO2 is selected from any value of 1, 2, 3, 4, 5 or a range between any two.

[0046] Optionally, the quaternary ammonium base template agent has the structural formula of Formula I:

[0047]

[0048] Wherein, R in formula I 1 R 2 R 3 R 4 Each is independently selected from any of the C1 to C4 alkyl groups, R 1 R 2 R 3 and R 4 Same or different.

[0049] Optionally, the quaternary ammonium base template agent is selected from tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide; preferably tetrapropylammonium hydroxide.

[0050] Optionally, in step S2, while stirring, the initial gel mixture C is added dropwise to the initial gel mixture B to obtain the gel mixture II.

[0051] Optionally, in step S3, the product after heating and crystallization II is separated, washed, and dried to obtain nanosheet-like graded porous TS-1 molecular sieve.

[0052] Optionally, in step S3, the molar content of SiO2 in the preform solution I is 3 to 10% of the molar content of SiO2 in the gel mixture II.

[0053] Optionally, in step S3, the molar content of SiO2 in the preform solution I is selected from any value of 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any range between two of the molar content of SiO2 in the gel mixture II.

[0054] Optionally, in step S1, crystallization I is dynamic crystallization.

[0055] Optionally, in step S1, the temperature of crystallization I is 60-140°C, and the time of crystallization I is 0.5-24h; preferably 80-120°C for 2-16h.

[0056] Optionally, in step S1, the temperature of crystallization I is selected from any value of 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, and 140℃, or a range between any two; the time of crystallization I is selected from any value of 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, and 24h, or a range between any two.

[0057] Optionally, in step S3, the temperature of crystallization II is 140–220°C, and the time of crystallization II is 0.5–48 h. Preferably, it is 160–200°C and 1–12 h.

[0058] Optionally, in step S3, the temperature of crystallization II is selected from any value of 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃ or any range between two; the time of crystallization I is selected from any value of 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 28, 30, 32, 35, 38, 40, 42, 44, 46, 48h or any range between two.

[0059] Optionally, the silicon source in the initial gel mixture A is selected from at least one of silica sol, methyl orthosilicate, and ethyl orthosilicate; the titanium source is selected from at least one of tetraethyl titanate, tetrabutyl titanate, and titanium isopropoxide.

[0060] Optionally, the silicon source in the gel mixture II is selected from at least one of silica sol, silica gel, silica gel for chromatography, methyl orthosilicate, ethyl orthosilicate, and silica fume.

[0061] Optionally, the titanium source is selected from at least one of tetraethyl titanate, tetrabutyl titanate, titanium tetrachloride, titanium sulfate, and titanium isopropoxide.

[0062] Optionally, the alkali source R in the gel mixture II is selected from compounds having the structure of Formula I:

[0063]

[0064] In Formula I, R1, R2, and R3 are each independently selected from H or an alkyl group having 1 to 4 carbon atoms.

[0065] Optionally, the alkali source R is selected from at least one of ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, n-propylamine, di-n-propylamine, tri-n-propylamine, isopropylamine, diisopropylamine, triisopropylamine, n-butylamine, di-n-butylamine, and tri-n-butylamine.

[0066] Optionally, the protective agent S is selected from at least one of ethanol, isopropanol, and acetylacetone.

[0067] Optionally, in step S1, the solid in the preform solution I has an amorphous structure with a particle size of 10-20 nm and contains a five-membered ring structure.

[0068] Optionally, in step S3, the titanium-silicon molecular sieve TS-1 is calcined in air at a temperature of 400–600°C.

[0069] Optionally, in step S3, the roasting temperature is selected from any value or a range between any two of 400℃, 420℃, 450℃, 470℃, 190℃, 500℃, 520℃, 550℃, 580℃, and 600℃.

[0070] Secondly, the present invention provides a titanium-silicon molecular sieve TS-1, which is synthesized by the above-described synthesis method.

[0071] Optionally, the titanium-silicon molecular sieve TS-1 has an MFI topology, wherein the Ti species have a four-coordinate structure.

[0072] Optionally, the titanium-silicon molecular sieve TS-1 has a hierarchical pore structure consisting of mesopores, macropores, and micropores; the pore volume of the mesopores is 0.2–0.3 cm³. 3 g -1 The pore size of the medium and large pores is distributed between 20 and 120 nm.

[0073] Optionally, the titanium-silicon molecular sieve TS-1 has a sheet-like morphology, with the sheet length, width, and thickness being 600–800 nm, 400–600 nm, and 80–120 nm, respectively.

[0074] In this application, "silicon-to-titanium ratio" refers to the molar ratio of silicon to titanium.

[0075] Compared with the prior art, the present invention has the following beneficial effects:

[0076] (1) The method provided by the present invention can synthesize a graded porous titanium silicon single crystal molecular sieve with a medium-microporous structure by using only a small amount of microporous template agent without introducing a hard template agent, with a product yield of 90%, under the assistance of a high-activity crystal embryo solution.

[0077] (2) The product obtained by the method provided by the present invention has a single Ti coordination, a high Ti content in the skeleton, and a high product yield.

[0078] (3) Compared with the prior art, the method provided by the present invention does not use hard template agents in the whole process, nor does it require complicated post-processing and separation processes. The synthesis cost is lower, the crystallization time is greatly reduced, the production efficiency is improved, and the production energy consumption is reduced. It is conducive to the large-scale production of titanium silicon molecular sieves. Attached Figure Description

[0079] Figure 1 The X-ray diffraction pattern of the preform powder 1# provided in Example 1 of this invention;

[0080] Figure 2 The infrared spectrum of the preform powder 1# provided in Example 1 of this invention;

[0081] Figure 3The X-ray diffraction pattern of sample 1# provided in Embodiment 1 of the present invention;

[0082] Figure 4 The image is a transmission electron microscope image of sample 1# provided in Embodiment 1 of the present invention;

[0083] Figure 5 The ultraviolet diffuse reflectance spectrum of sample 1# provided in Example 1 of this invention;

[0084] Figure 6 The physical adsorption spectrum of sample 1# provided in Example 1 of this invention;

[0085] Figure 7 The pore size distribution diagram of sample 1# provided in Embodiment 1 of the present invention;

[0086] Figure 8 The X-ray diffraction pattern of the preform powder comparison sample 1# provided in Comparative Example 1 of this invention;

[0087] Figure 9 The ultraviolet diffuse reflectance spectrum of comparative sample 1# provided for Comparative Example 1 of this invention. Detailed Implementation

[0088] The present application is further illustrated below with reference to specific embodiments. The following descriptions are merely a few embodiments of the present application and are not intended to limit the present application in any way. Although the present application discloses preferred embodiments as follows, they are not intended to limit the present application. Any modifications or variations made by those skilled in the art without departing from the scope of the technical solution of the present application using the disclosed technical content are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

[0089] Unless otherwise specified, all raw materials and reagents used in this application are commercially purchased and used directly without processing. The instruments and equipment used adopt the manufacturer's recommended scheme and parameters.

[0090] The analysis method in the embodiments of this application is as follows:

[0091] X-ray powder diffraction (XRD) phase analysis was performed using an X'Pert PRO X-ray diffractometer from PANalytical, Netherlands, with a Cu target, a Kα radiation source (λ = 0.15418 nm), a voltage of 40 kV, and a current of 40 mA.

[0092] Elemental composition was determined using a Philips Magix 2424 X-ray fluorescence analyzer (XRF).

[0093] The pore structure of the samples was characterized by low-temperature nitrogen physical adsorption using a Micromeritics ASAP2020 physical adsorption instrument. The specific surface area was calculated using the BET formula, and the pore distribution was calculated using the BJH formula.

[0094] The sample yield was calculated using the following formula:

[0095] Yield = (mass of the calcined sample) ÷ (mass of SiO2 in mixture III + mass of TiO2) × 100%.

[0096] Example 1 Sample 1 # Synthesis

[0097] A homogeneous mixed solution with a molar ratio of 1:16H2O was prepared using tetraethyl orthosilicate as the silicon source, tetraethyl titanate as the titanium source, and tetrapropylammonium hydroxide as the template agent. This solution was then placed in a synthesis reactor lined with polytetrafluoroethylene and crystallized at 120°C for 18 hours to obtain homogeneous preform solution I. A portion of the preform solution was neutralized with stoichiometric acetic acid to obtain a solid powder. The powder was dried and calcined to obtain a sample, designated as preform powder 1#.

[0098] Using methyl orthosilicate as the silicon source, tetrabutyl titanate as the titanium source, diethylamine as the base source, and anhydrous ethanol as the protective agent, SiO2:0.028TiO2:0.08C4H was obtained according to the following steps. 11 N:0.05S:12H2O mixed solution II. At this time, crystal embryo solution I is added to mixed solution II, wherein the SiO2 content of crystal embryo solution I accounts for 10% of the SiO2 content of mixed solution II, forming a final mixed solution. The mixed solution is placed in a synthesis kettle with a polytetrafluoroethylene liner and crystallized at 175℃ for 8 hours to obtain titanium silicon molecular sieve. The product is centrifuged, washed, dried and calcined to obtain the final molecular sieve product, which is recorded as sample 1#. XRF results show that the Si / Ti of the product is 38.6.

[0099] Example 2: Preparation of Samples 2# to 19#

[0100] Sample 2 # ~19 # The types of raw materials, raw material ratios, and crystallization conditions are shown in Table 1. The preparation process is the same as that of Sample 1 in Example 1. # Preparation of .

[0101] Table 1. Molecular sieve synthesis ingredients and crystallization conditions in Examples 1-19

[0102]

[0103]

[0104] Comparative Example 1 vs. Comparative Sample 1 # Preparation

[0105] The specific ingredient ratios, ingredient preparation process, and crystallization conditions are the same as those for sample 1 in Example 1. # The preparation method involved omitting the Ti source during the preparation of the preform solution I. The resulting preform solution was neutralized with stoichiometric acetic acid to obtain a solid powder, and this sample was designated as preform powder control sample 1#. The final sample synthesized using the preform solution from control example 1 was also designated as control sample 1#.

[0106] Example 20 Sample 1 # ~19 # XRD and IR analysis of the synthetic embryo solution containing solids

[0107] The crystal embryo solutions prepared in the examples all showed amorphous XRD patterns, indicating an amorphous state. However, infrared (IR) characterization revealed numerous characteristic peaks at positions consistent with those of MFI zeolite, belonging to a 5-membered ring structure. A typical example is... Figure 1 The XRD pattern of preform powder 1# shows that the preform powder has an amorphous structure. The XRD patterns of preform powders 2#-19# are similar to those of preform powder 1#. Figure 1 The proximity indicates that both are amorphous structures; Figure 2 The IR spectrum of the preform powder #1 shows that at 550 cm⁻¹... -1 There are characteristic peaks nearby that can be attributed to a 5-membered ring structure. The IR spectra of the preform powder 2#-19# are similar to those of the preform powder. Figure 2 Approximately 550cm -1 Vibrational peaks consistent with those of MFI-structured zeolites can be observed in the vicinity, indicating that the synthesized embryo contains zeolite structural units.

[0108] Example 21

[0109] Sample 1 # ~19 # XRD, SEM, UV-Vis, N2 physical adsorption, and pore size distribution analysis of sample 1 were performed using X-ray diffraction, scanning electron microscopy, and ultraviolet diffuse reflectance. # ~19 # Perform the analysis.

[0110] Sample 1 prepared in the example # ~19 # All are high-purity and highly crystallinity TS-1 molecular sieves with MFI topology, typical examples include... Figure 3 Medium sample 1 # XRD pattern of sample 2. # ~19 # The XRD patterns of sample 1 show that the peak positions and shapes are basically the same, and the relative peak intensities fluctuate within ±5% depending on the synthesis conditions, indicating that sample 1# ~19 # It has the characteristics of MFI structure and is free of impurities.

[0111] Sample 1 # ~19 # All of them have a nanosheet-like morphology, with typical examples being... Figure 4 The SEM image of sample 1# shows that the product has a sheet-like structure with dimensions of approximately 600nm*400nm*100nm. The particle size is relatively uniform, and the cross-section shows that it is composed of a large number of small particles with a size of 10-20nm. Sample 2 # ~19 # The SEM image results show that the product morphology and particle size are related to Figure 1 Sample #1 has similar dimensions.

[0112] Sample 1 # ~19 # All Ti species exist as Ti species with a four-coordinated skeleton, a typical example being... Figure 5 The UV-Vis image of sample 1# shows that Ti in the product mainly exists in the form of tetracoordinate (210-220nm), with almost no non-framework Ti (230-270nm) or nano TiO2 (310-330nm); Sample 2 # ~19 # The UV-Vis pattern is similar to that of sample #1, mainly consisting of tetracoordinated species, with no non-skeleton Ti or TiO2 species present.

[0113] Figure 6 and Figure 7 The images show the physical adsorption curves and pore size distribution of the product. It can be seen that, while maintaining the micropore volume, the mesopore and macropore volume of the product reaches 0.22 cm³. 3 g -1 The pore size of the medium and large pores is distributed between 20-120 nm; Sample 2 # ~19 # The physical adsorption curves and pore size distributions are respectively compared with Figure 6 and Figure 7 Similarly, it can be seen that the product obtained by the present invention has both high framework Ti content and hierarchical pore structure, and the product yield can reach 90%.

[0114] Example 22: XRD analysis of the preform powder in Comparative Example 1# compared to Sample 1#

[0115] Figure 8 The XRD pattern of the seed crystal powder comparison sample 1# shows that the seed crystal comparison sample 1# already has a topological structure that can be partially attributed to MFI.

[0116] Example 23: UV-Vis Analysis of Comparative Example 1#

[0117] The XRD, SEM, and physical adsorption results (not shown) of sample 1# are similar to those of sample 1#; however, its UV-Vis... Figure 9 As shown, in addition to containing skeletal Ti, comparative sample 1# also contains a large number of non-skeletal Ti species (230-270 cm⁻¹). -1 ).

[0118] In Comparative Example 1, without the addition of Ti, the preform was crystallized at 120°C for 18 hours at the same crystallization temperature. The synthesized preform grew significantly, and the final synthesized molecular sieve contained a large number of non-framework Ti species.

[0119] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for synthesizing a hierarchical porous titanium-silicon molecular sieve TS-1, characterized in that, The method includes the following steps: S1: Raw materials containing silicon source, titanium source, quaternary ammonium base template agent and water are mixed to obtain initial gel mixture A. The initial gel mixture A is heated and crystallized I under closed conditions to obtain preform solution I. The solid in the preform solution I has an amorphous structure with a particle size of 10 ~ 20 nm and the particle structure contains a five-membered ring structure. S2: Raw materials containing silicon source, alkali source R, water, titanium source and protective agent S are mixed to obtain gel mixture II; S3: The preform solution I in step S1 and the gel mixture II in step S2 are mixed to obtain gel mixture III. The gel mixture III is heated and crystallized under closed conditions to obtain the hierarchical porous titanium silicon molecular sieve TS-1. In step S1, the temperature of crystallization I is 60 ~ 140℃, and the time of crystallization I is 0.5 ~ 24h; In step S3, the titanium-silicon molecular sieve TS-1 is calcined in air at a temperature of 400~600℃.

2. The method for synthesizing a hierarchical porous titanium-silicon molecular sieve TS-1 according to claim 1, characterized in that, In step S1, the molar ratio of the silicon source, the titanium source, the quaternary ammonium base template agent, and the water in the initial gel mixture A is: Template agent: SiO2 = 0.10 ~ 0.50:1; TiO2:SiO2=0.02~0.05:1; H2O:SiO2 = 4 ~ 20:1; Wherein, the number of moles of the silicon source is calculated as the number of moles of SiO2, the number of moles of the titanium source is calculated as the number of moles of TiO2, the number of moles of the template agent is calculated as the number of moles of quaternary ammonium base, and the number of moles of water is calculated as the number of moles of H2O.

3. The method for synthesizing a hierarchical porous titanium-silicon molecular sieve TS-1 according to claim 1, characterized in that, In step S2, the molar ratio of the silicon source, the titanium source, the alkali source R, the protective agent S, and the water in the gel mixture II is: SiO2: TiO2: R: S: H2O = 1: (0.02 ~ 0.10): (0.02 ~ 0.20): (0.02 ~ 0.2): (6 ~ 30); Wherein, the number of moles of the silicon source is calculated as the number of moles of SiO2, the number of moles of the titanium source is calculated as the number of moles of TiO2, the number of moles of R is calculated as the number of moles of the alkali source R, the number of S is calculated as the number of moles of the protective agent S, and the number of moles of water is calculated as the number of moles of H2O.

4. The method for synthesizing a hierarchical porous titanium-silicon molecular sieve TS-1 according to claim 1, characterized in that, The gel mixture II in step S2 is obtained by mixing the initial gel mixture B and the initial gel mixture C; The initial gel mixture B is obtained by mixing a silicon source, an alkali source R, and water; the molar ratio of each component in the initial gel mixture B is: R:SiO2 = 0 ~ 0.20:1; H2O:SiO2 = 6 ~ 30:1; The initial gel mixture C is obtained by mixing a titanium source and a protective agent S; the molar ratio of each component in the initial gel mixture C is: S:TiO2 = 1 ~ 5:1; Wherein, the number of moles of the silicon source is calculated as the number of moles of SiO2, the number of moles of the titanium source is calculated as the number of moles of TiO2, the number of moles of the alkali source R is calculated as the number of moles of R, the number of moles of the protective agent S is calculated as the number of moles of S, and the number of moles of water is calculated as the number of moles of H2O.

5. The method for synthesizing a hierarchical porous titanium-silicon molecular sieve TS-1 according to claim 1, characterized in that, The structural formula of the quaternary ammonium base template agent is Formula I: Equation I; Wherein, R in formula I 1 R 2 R 3 R 4 Each is independently selected from any of the C1-C4 alkyl groups, R 1 R 2 R 3 and R 4 Same or different.

6. The synthesis method according to claim 5, characterized in that, The quaternary ammonium base template agent is selected from tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.

7. The method for synthesizing a hierarchical porous titanium-silicon molecular sieve TS-1 according to claim 1, characterized in that, In step S3, the molar content of SiO2 in the preform solution I is 3 to 10% of the molar content of SiO2 in the gel mixture II.

8. The method for synthesizing a hierarchical porous titanium-silicon molecular sieve TS-1 according to claim 1, characterized in that, In step S3, the temperature of crystallization II is 140 ~ 220℃, and the time of crystallization II is 0.5 ~ 48h.

9. The method for synthesizing a hierarchical porous titanium-silicon molecular sieve TS-1 according to claim 1, characterized in that, The silicon source in the initial gel mixture A is selected from at least one of silica sol, methyl orthosilicate, and tetraethyl orthosilicate; the titanium source is selected from at least one of tetraethyl titanate, tetrabutyl titanate, and titanium isopropoxide.

10. The method for synthesizing a hierarchical porous titanium-silicon molecular sieve TS-1 according to claim 1, characterized in that, The silicon source in the gel mixture II is selected from at least one of silica sol, silica gel, silica gel for chromatography, methyl orthosilicate, ethyl orthosilicate, and silica fume; the titanium source is selected from at least one of tetraethyl titanate, tetrabutyl titanate, titanium tetrachloride, titanium sulfate, and titanium isopropoxide.

11. The method for synthesizing a hierarchical porous titanium-silicon molecular sieve TS-1 according to claim 1, characterized in that, The alkali source R in the gel mixture II is selected from compounds having the structure of formula II: Formula II; In Formula II, R1, R2, and R3 are each independently selected from H or an alkyl group having 1 to 4 carbon atoms.

12. The synthesis method according to claim 11, characterized in that, The alkali source R in the gel mixture II is selected from at least one of ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, n-propylamine, di-n-propylamine, tri-n-propylamine, isopropylamine, diisopropylamine, triisopropylamine, n-butylamine, di-n-butylamine, and tri-n-butylamine; The protective agent S is selected from at least one of ethanol, isopropanol, and acetylacetone.

13. A hierarchical porous titanium-silicon molecular sieve TS-1, characterized in that, It is synthesized by the synthesis method of titanium-silicon molecular sieve TS-1 as described in any one of claims 1 to 12.

14. The multi-level porous titanium-silicon molecular sieve TS-1 according to claim 13, characterized in that, The titanium-silicon molecular sieve TS-1 has a hierarchical pore structure consisting of mesopores, macropores, and micropores; the pore volume of the mesopores is 0.2 ~ 0.3 cm³. 3 g -1 The pore size of the mesopores is distributed between 20 and 120 nm.

15. The hierarchical porous titanium-silicon molecular sieve TS-1 according to any one of claims 13 or 14, characterized in that, The titanium-silicon molecular sieve TS-1 has an MFI topology, in which the Ti species have a four-coordinate structure; the titanium-silicon molecular sieve TS-1 has a sheet-like morphology, with the sheet length, width and thickness being 600 ~ 800 nm, 400 ~ 600 nm and 80 ~ 120 nm, respectively.

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