Titanium species self-supporting molecular sieve with open structure as well as preparation method and application of titanium species self-supporting molecular sieve
By controlling the aging and crystallization conditions of titanium silicon molecular sieve, synthesis without additional additives was achieved, and the micropore-mesoporous multi-stage pores and open structure framework titanium species were constructed in a coordinated manner, which solved the problem of morphology and titanium activity center regulation of titanium silicon molecular sieve and improved catalytic activity.
Patent Information
- Application Number
- CN202510282147.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-11
- Publication Date
- 2025-06-10
AI Technical Summary
The existing titanium silicon molecular sieve has difficulties in morphology/channel structure and titanium active center regulation, and traditional synthesis methods require additional additives, resulting in high preparation costs and skeleton damage.
By controlling the aging and crystallization conditions during the synthesis of titanium silicon molecular sieve, a method without additional additives is adopted to jointly construct micropore-mesoporous multi-stage pores and open-structure skeleton titanium species to form a self-supporting morphology of molecular sieve.
The coordinated regulation of titanium silicon molecular sieve morphology/pore structure and titanium active center was achieved, and a large outer specific surface area and high-active open structure skeleton titanium species were obtained, which improved catalytic activity.
Smart Images
Figure CN120117618A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of molecular sieves, and specifically to a self-supporting molecular sieve with open-structured titanium species, a preparation method thereof, and an application thereof. Background Art
[0002] As the most typical heteroatom-substituted molecular sieve, titanium silicalite molecular sieve can carry out green synthesis of chemicals with oxidant H 2 O 2 and is applied to catalytic fields including olefin epoxidation, partial oxidation of alkanes, hydroxylation of phenol, ammoximation of ketones, oxidative desulfurization, etc., avoiding many problems such as the generation of by-products and environmental pollution in the reaction. Therefore, it has important significance in industry. This has greatly stimulated people's research interest. Among the research results, the more prominent ones are TS-1 (MFI topology) and TS-2 (MEL topology) of the Pentasil family. US04410501A first publicly reported the synthesis of TS-1. In 1983, Taramasso et al. successfully carried out hydrothermal synthesis with tetrapropylammonium hydroxide as the organic base and adding a mixture composed of a silica source, a titanium dioxide source, and water. TS-2 was successfully prepared by Reddy et al. using the hydrothermal synthesis method. Using tetrabutylammonium hydroxide as the template agent, tetraethyl orthosilicate and tetrabutyl titanate as the silica source and the titanium source, the new type of titanium silicate TS-2 was successfully synthesized (J. Catal., 1991, 130, 440).
[0003] The activity of traditional titanium silicalite molecular sieves is restricted by microporous channels and the closed tetracoordinated titanium species distributed therein. In order to improve the catalytic activity of titanium silicalite molecular sieves, constructing a microporous-mesoporous hierarchical pore system and regulating the microchemical environment of titanium active sites have become research hotspots in this field. The methods for constructing hierarchical pores include the construction method and the destruction method. In the construction method, the porous structure is realized by introducing hard templates and soft templates during the preparation of zeolites. Du Shuting et al. used the surfactant Triton X-100 as the mesoporous template and successfully synthesized hierarchical TS-1 with uniform intracrystalline mesopores by the hydrothermal method (Chem. Commun., 2016, 52, 3368). The post-treatment destructive method for introducing secondary pores is to selectively remove framework atoms (such as Si, Al, Ti, B) from microporous zeolites by acid leaching, alkali leaching, steaming, or irradiation. A. Silvestre-Albero et al. carried out desilication treatment on the original TS-1 (4wt% Ti) with NaOH. The desilicated TS-1 has a larger specific surface area and well-developed mesopores (Catal. Commun., 2014, 44, 35). In addition, with the progress of characterization and synthesis technologies, researcher Wu Lizhi prepared a (Ti(OSi) with an open structure by the post-treatment method of organic base ethylamine 3TS-1 molecular sieve with (OH) framework titanium species exhibits much higher catalytic activities for olefin epoxidation and cyclohexanone ammoximation reactions than traditional TS-1 molecular sieves (closed (Ti(OSi) 4 framework titanium species) (Chem. Commun., 2018, 54, 6384). Xu Bowen et al. successfully synthesized OH-Ti-β zeolite with open Ti(OSi) 4 (OH) sites by treating Ti-β zeolite with NH 3 F in methanol. Compared with the parent Ti-Beta, this zeolite shows superior catalytic performance in the epoxidation reaction of cyclohexene (J. Catal., 2024, 439, 115748).
[0004] However, the above-mentioned construction of titanium active species with hierarchical pores requires adding additives to the original synthesis system of titanium silicate molecular sieves. The synthesis steps are cumbersome, the preparation cost is increased, which is not conducive to industrial production and application. At the same time, the above synthesis process also faces defects such as the destruction of the molecular sieve framework, the reduction of crystallinity, and the loss of framework titanium. Summary of the Invention
[0005] The purpose of the present invention is to provide a self-supporting molecular sieve with open-structured titanium species, its preparation method and application, so as to solve the problem of difficult regulation of the morphology / pore structure and titanium active center of titanium silicate molecular sieves in the prior art.
[0006] The present invention is realized as follows:
[0007] A preparation method of a self-supporting molecular sieve with open-structured titanium species, comprising the following steps:
[0008] (1) Prepare a silicon source, a titanium source, an organic base and water as raw materials;
[0009] (2) Add the organic base to water, stir, and then add the silicon source and stir well to obtain a reaction gel;
[0010] (3) Place the obtained reaction gel in a reaction kettle, seal the reaction kettle and then age it, and then carry out the first crystallization;
[0011] (4) After the first crystallization, take out the reaction kettle, cool it, and then dropwise add the titanium source into the liner. After stirring to make the reaction uniform, seal the reaction kettle and carry out the second crystallization;
[0012] (5) Centrifuge the reaction solution obtained after the second crystallization, wash it with water until the reaction solution is neutral, then wash it with absolute ethanol, dry it to obtain molecular sieve powder, and calcine the molecular sieve powder to obtain a self-supporting molecular sieve with open-structured titanium species.
[0013] Preferably, in the above solution, the titanium source is at least one of titanium chloride, titanium sulfate, tetraethyl titanate, tetrabutyl titanate, isopropyl titanate, tetrabutyl titanate tetramer, and ammonium hexafluorotitanate.
[0014] Preferably, in the above solution, the silicon source is at least one of tetraethyl orthosilicate, silica sol, nano-silica, and water glass.
[0015] Preferably, in the above solution, the organic base is at least one of tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapropylammonium bromide, and tetrabutylammonium bromide.
[0016] Preferably, in step (1) of the above solution, the molar ratio of the silicon source, titanium source, organic base, and water is 1.0:0.025:0.3:30.
[0017] Preferably, in step (3) of the above solution, the aging process conditions are: aging in an oven at 80 °C for 2 days; the first crystallization process conditions are: crystallization in an oven at 120 °C for 12 - 24 hours.
[0018] Preferably, in step (4) of the above solution, the secondary crystallization process conditions are: crystallization in an oven at 120 °C for 1 - 4 days or crystallization in a microwave oven at 120 °C for 4 hours.
[0019] Preferably, in step (5) of the above solution, the process conditions for calcining the molecular sieve powder are: calcining at a temperature of 550 °C for 6 hours.
[0020] In the synthesis process of the molecular sieve of the present invention, no additional additives are added to regulate the morphology of the molecular sieve and titanium species.
[0021] The self-supporting molecular sieve with open-structured titanium species prepared according to the method of the present invention forms ordered mutually supporting nanosheets with a thickness of 2 - 10 nm on its surface. The nanosheets grow in an overlapping and staggered manner, and there is an intercrystalline mesoporous structure with a size of 2 - 20 nm between the nanosheets. This molecular sieve has a characteristic peak attributed to the Ti(OSi) 3 (OH) framework titanium species at 230 nm in the ultraviolet-visible spectrum.
[0022] The self-supporting molecular sieve with open-structured titanium species prepared according to the method of the present invention can be used as a catalyst in the epoxidation reaction of 1-octene.
[0023] The present invention is a method for synergistically constructing microporous-mesoporous hierarchical pores and open-structured framework titanium species in titanium silicate molecular sieves without additional additives. The Ti OH -SPP molecular sieve prepared by the present invention has a morphology of overlapping and staggered nanosheets, a large external specific surface area, pore volume, and a large number of highly active open structures (Ti(OSi) 3Skeleton titanium species of (OH).
[0024] By regulating the aging / crystallization conditions (temperature, time) and modes (hydrothermal, microwave-assisted), as well as the types and component ratios of silicon / titanium sources, intermediate Pentasil zeolites with different crystallization states are obtained. It has a self-supporting morphology and captures titanium to form an open structure of skeleton titanium. Finally, under the condition of no additional additives, the synergistic regulation of the morphology / pore structure and titanium active centers of titanium silicate zeolites is realized. Description of the Drawings
[0025] Figure 1 It is the X-ray diffraction pattern of the zeolite material obtained in Example 1 of the present invention.
[0026] Figure 2 It is the X-ray diffraction pattern of the zeolite material obtained in Comparative Example 1 of the present invention.
[0027] Figure 3 It is the X-ray diffraction pattern of the zeolite material obtained in Comparative Example 2 of the present invention.
[0028] Figure 4 It is the comparison diagram of the ultraviolet-visible spectra of the zeolite materials obtained in Example 1 and Comparative Examples 1-2 of the present invention.
[0029] Figure 5 It is the transmission electron microscope image of the zeolite material obtained in Example 1 of the present invention.
[0030] Figure 6 It is the transmission electron microscope image of the zeolite material obtained in Comparative Example 1 of the present invention.
[0031] Figure 7 It is the transmission electron microscope image of the zeolite material obtained in Comparative Example 2 of the present invention. Detailed Description of the Invention
[0032] The present invention will be further described in detail below with reference to specific examples.
[0033] Example 1
[0034] The preparation method of the self-supporting zeolite with open structure titanium species provided in this example includes the following steps:
[0035] Step 1, calculate the amounts of the required raw materials of silicon source, titanium source, organic base, and water according to the molar composition ratio of each raw material: silicon source: titanium source: organic base: water = 1.0: 0.025: 0.3: 30. Among them, the silicon source is tetraethyl orthosilicate, the titanium source is tetrabutyl titanate, and the organic base is tetrabutylammonium hydroxide (TBAOH).
[0036] Step 2: Add tetrabutylammonium hydroxide into water. After stirring for 0.5 hours, add tetraethyl orthosilicate (faster than adding drop by drop, and it can be controlled within 10 minutes), and stir thoroughly for 4 hours to obtain a reaction gel.
[0037] Step 3: Place the obtained reaction gel in a reaction kettle. After sealing the reaction kettle, age it in an oven at 80 °C for 2 days, and then crystallize it for the first time in an oven at 120 °C for 1 day.
[0038] Step 4: Take out the reaction kettle. After cooling, directly add tetrabutyl titanate drop by drop into the liner (add drop by drop within 0.5 hours). After stirring for 1 h until the reaction is uniform, seal the reaction kettle and crystallize it for the second time in an oven at 120 °C for 1 day.
[0039] Step 5: Centrifuge the reaction solution obtained after the second crystallization, wash it with water until the pH of the reaction solution is 7, then wash it once with absolute ethanol, dry it to obtain molecular sieve powder, and calcine it at 550 °C for 6 hours to obtain self-supported molecular sieve Ti OH -SPP with an open structure titanium species.
[0040] Example 2: The implementation process is the same as that of Example 1 except for the different first crystallization time.
[0041] Example 3: The implementation process is the same as that of Example 1 except for the different second crystallization time.
[0042] Example 4: The implementation process is the same as that of Example 1 except for the different second crystallization time and crystallization method.
[0043] Examples 5 - 7: The titanium sources are different in the implementation process. In Example 5, tetraethyl titanate is used; in Example 6, tetrabutyl titanate tetramer is used; in Example 7, ammonium hexafluorotitanate is used. The rest are the same as those in Example 1.
[0044] Table 1 below is a comparison table of the titanium sources and the aging and crystallization process conditions in the above Examples 1 - 7.
[0045] Table 1 Comparison Table of Titanium Sources and Aging and Crystallization Process Conditions in Examples 1 - 7
[0046] Serial number Aging First crystallization Titanium source Second crystallization Example 1 2 days in an oven at 80°C 1 day in an oven at 120°C Tetrabutyl titanate 1 day in an oven at 120°C Example 2 2 days in an oven at 80°C 12 hours in an oven at 120°C Tetrabutyl titanate 1 day in an oven at 120°C Example 3 2 days in an oven at 80°C 1 day in an oven at 120°C Tetrabutyl titanate 4 days in an oven at 120°C Example 4 2 days in an oven at 80°C 1 day in an oven at 120°C Tetrabutyl titanate 4 hours by microwave at 120°C Example 5 2 days in an oven at 80°C 1 day in an oven at 120°C Tetraethyl titanate 1 day in an oven at 120°C Example 6 2 days in an oven at 80°C 1 day in an oven at 120°C Tetrabutyl titanate tetramer 1 day in an oven at 120°C Example 7 2 days in an oven at 80°C 1 day in an oven at 120°C Ammonium hexafluorotitanate 1 day in an oven at 120°C
[0047] Comparative Example 1
[0048] This comparative example provides a preparation method of TS-1 - traditional molecular sieve, and the specific steps are as follows:
[0049] Step 1: Calculate the amounts of the required raw materials, namely silicon source, titanium source, organic base, and water, according to the molar composition ratio of each raw material as silicon source: titanium source: organic base: water = 1.0: 0.025: 0.15: 30. Among them, the organic base is tetrapropylammonium hydroxide, the silicon source is tetraethyl orthosilicate, and the titanium source is tetrabutyl titanate.
[0050] Step 2: Add tetrapropylammonium hydroxide to water and stir for 0.5 hours.
[0051] Step 3: Add tetrabutyl titanate dropwise (dropwise addition within 0.5 hours) under stirring, and stir for 1 h to react evenly.
[0052] Step 4: Add tetraethyl orthosilicate under stirring (faster than dropwise addition, controlled within 10 min), and stir thoroughly for 4 hours to obtain a reaction gel.
[0053] Step 5: Place the obtained reaction gel in a reaction kettle. After sealing the reaction kettle, place it in an oven at 100 °C for 2 hours, and then transfer the reaction kettle to an oven at 170 °C for crystallization for 2 days.
[0054] Step 6: Centrifuge the obtained reaction solution, wash it with water until the pH of the reaction solution is 7, then wash it once with absolute ethanol, dry it to obtain molecular sieve powder, and calcine it at 550 °C for 6 hours to obtain TS-1 - traditional molecular sieve.
[0055] Comparative Example 2
[0056] This comparative example provides a preparation method of TS-2 - traditional molecular sieve, and the specific steps are as follows:
[0057] Step 1: Calculate the amounts of the required raw materials, namely silicon source, titanium source, organic base, water, and alcohol, according to the molar composition ratio of each raw material as silicon source: titanium source: organic base: water: alcohol = 1.0: 0.025: 0.25: 25: 0.33. The organic base is tetrabutylammonium hydroxide, the silicon source is tetraethyl orthosilicate, the titanium source is tetrabutyl titanate, and the alcohol is ethanol.
[0058] Step 2: Add tetrabutylammonium hydroxide to water and stir for 0.5 hours.
[0059] Step 3: Add tetraethyl orthosilicate dropwise to the aqueous solution of tetrabutylammonium hydroxide under stirring, and then add deionized water to form a mixed solution A.
[0060] Step 4: Mix tetrabutyl titanate and ethanol to form solution B, and quickly add solution B to solution A.
[0061] Step 5: After stirring for 30 min, age and stir for 5 h under the condition of a 60 °C water bath to form a transparent and clear suspension.
[0062] Step 6: Transfer the obtained suspension into a reaction kettle. After sealing the reaction kettle, crystallize it in an oven at 170 °C for 3 days.
[0063] Step 7: Centrifuge the obtained reaction solution, wash it with water until the pH of the reaction solution is 7, then wash it once with absolute ethanol, and dry it to obtain molecular sieve powder. Calcinate it at 550 °C for 6 hours to obtain TS-2-conventional molecular sieve.
[0064] Material Characterization and Performance Testing
[0065] The X-ray diffraction pattern of the molecular sieve Ti OH -SPP prepared in Example 1 of the present invention is as Figure 1 shown. It can be seen from Figure 1 that the molecular sieve Ti OH -SPP prepared in Example 1 exhibits typical characteristic peaks of self-supporting pentasil molecular sieve morphology.
[0066] Figure 2 And Figure 3 are the X-ray diffraction patterns of the molecular sieve materials prepared in Comparative Example 1 and Comparative Example 2 respectively. It can be seen from Figure 2 and Figure 3 that the TS-1-conventional molecular sieve diagram prepared in Comparative Example 1 and the TS-2-conventional molecular sieve diagram prepared in Comparative Example 2 both have characteristic peaks of MFI topological structure.
[0067] Figure 4 is the comparative ultraviolet-visible spectrum diagram of the molecular sieve materials prepared in Example 1, Comparative Example 1 and Comparative Example 2. It can be seen from Figure 4 that in Example 1, in addition to the closed tetracoordinated framework titanium (absorption peak at 210 nm), there is also a large amount of open framework titanium (absorption peak at 230 nm); in Comparative Example 1, there is only closed tetracoordinated framework titanium (absorption peak at 210 nm); in Comparative Example 2, in addition to the closed tetracoordinated framework titanium (absorption peak at 210 nm), a large amount of harmful anatase species (absorption peak at 320 nm) are generated.
[0068] The ultraviolet-visible spectrum tests were carried out on the molecular sieve materials obtained in Examples 1-7 and Comparative Examples 1-2, and the results are shown in Table 2 below.
[0069] Table 2 Analysis and comparison table of titanium species distribution of the molecular sieve materials obtained in Examples 1-7 and Comparative Examples 1-2
[0070] Closed framework titanium (%) Open framework titanium (%) Non-framework titanium (%) Example 1 41.3 58.7 0 Example 2 53.4 46.6 0 Example 3 39.5 60.5 0 Example 4 37.6 62.4 0 Example 5 60.3 39.7 0 Example 6 35.1 64.9 0 Example 7 56.2 23.5 20.3 Comparative example 1 100 0 0 Comparative example 2 65.2 0 34.8
[0071] In the ultraviolet-visible spectrum diagram of the molecular sieve material, the closed framework titanium is located at 210 nm, the open framework titanium is located at 230 nm, and the non-framework titanium includes amorphous TiO 2(at 260 - 290 nm) and anatase TiO 2 (at 320 nm).
[0072] As can be seen from Table 2, the molecular sieve materials prepared in Examples 1 - 7 of the present invention contain a large amount of open-framework titanium. In particular, in Examples 1, 3, 4, and 6, the content of open-framework titanium in the molecular sieve materials reaches 58.7% - 64.9%. In Comparative Example 1 and Comparative Example 2, the TS-1-conventional molecular sieve and TS-2-conventional molecular sieve prepared by the traditional process do not contain open-framework titanium. Moreover, in the TS-2-conventional molecular sieve, there are also 34.8% of harmful anatase species.
[0073] Figures 5 - 7 They are the transmission electron microscope images of the molecular sieve materials prepared in Example 1, Comparative Example 1, and Comparative Example 2 respectively. Figure 5 The transmission electron microscope photograph therein shows that the molecular sieve Ti OH -SPP exhibits a typical self-supporting morphology, with a grain size of 150 - 200 nm, which is composed of 2 - 10 nm ultra-thin molecular sieve nanosheets vertically and staggeredly built, and there are a large number of intercrystalline mesopores of about 4 nm between them. Figure 6 The transmission electron microscope photograph therein shows that the TS-1-conventional molecular sieve is ellipsoidal, with a grain size of about 600 nm. Figure 7 The transmission electron microscope photograph therein shows that the TS-2-conventional molecular sieve is irregularly rectangular, with a grain size in the range of 200 - 500 nm.
[0074] The nitrogen adsorption and desorption tests were carried out on the molecular sieve materials prepared in Example 1, Comparative Example 1, and Comparative Example 2, and their physical and chemical properties were calculated as shown in Table 3 below.
[0075] Table 3 Comparison of the physical and chemical properties of the molecular sieve materials in Example 1 and Comparative Examples 1 - 2
[0076]
[0077]
[0078] In Table 3, S BET is the total specific surface area, S micro is the micropore specific surface area, S ext is the external specific surface area, and V total is the total pore volume. As can be seen from Table 3, compared with Comparative Example 1 and Comparative Example 2, the molecular sieve material with a self-supporting morphology in Example 1 has a significantly increased total specific surface area, external specific surface area, and total pore volume. This shows that Example 1 has a more open "micropore-mesopore" hierarchical pore system.
[0079] Catalytic activity test of molecular sieve materials
[0080] Using the epoxidation reaction of 1-octene as a probe reaction to characterize the catalytic activity of the molecular sieve, and its specific application is as follows:
[0081] 0.1 g of the molecular sieve catalyst, 1.145 g of 1-octene, 7.9 g of methanol, and 10 mmol of 30% mass concentration hydrogen peroxide were stirred and reacted at 60 °C for 6 h. After adding 0.5 g of cyclohexanone, the supernatant was taken and analyzed by gas chromatography (Fuli F80, FID), and the product conversion data was calculated, as shown in Table 4.
[0082] Table 4 Comparison table of the results of the epoxidation reaction of 1-octene catalyzed by the molecular sieves obtained in Examples 1-7 and Comparative Examples 1-2
[0083] 1-Octene conversion rate 1,2-Epoxyoctane selectivity Example 1 81.5 99.9 Example 2 58.0 99.7 Example 3 90.4 99.1 Example 4 96.6 99.0 Example 5 41.9 99.1 Example 6 97.9 99.9 Example 7 35.5 91.3 Comparative example 1 20.1 96.7 Comparative example 2 15.3 97.9
[0084] As can be seen from Table 4, in the epoxidation reaction of 1-octene, the molecular sieve materials prepared in Examples 1-7 of the present invention have a significant increase in the conversion rate of 1-octene compared with Comparative Examples 1 and 2. In particular, in Examples 1, 3, 4, and 6, the molecular sieve materials promoted the conversion rate of 1-octene to reach 81.5% - 97.9%.
[0085] By controlling the aging and crystallization conditions, the present invention obtains partially crystalline intermediate-state defective silicon fragments, and then captures titanium by these defective intermediate-state species to synthesize titanium silicalite molecular sieves with self-supporting morphology and open framework titanium species, which exhibit high catalytic activity in the epoxidation reaction of macromolecular olefins.
[0086] For the technical terms in the present invention, those with definitions shall be understood according to their definitions, and those without definitions shall be understood according to the common meanings in the art.
[0087] Definition:
[0088] "Titanium silicalite molecular sieve" is a molecular sieve material formed by the isomorphous substitution of silicon atoms in the molecular sieve by titanium atoms.
[0089] "Closed tetracoordinate titanium species" refers to the traditional framework Ti(OSi) 4 , which has the ability to catalyze selective oxidation reactions.
[0090] "(Ti(OSi) 3 (OH)) framework titanium species" refers to defective framework titanium species, which have stronger activity than traditional TiO 4 in catalytic reactions.
[0091] "Pentasil family" is a family of molecular sieves with a five-membered ring type, which includes MFI-type Pentasil molecular sieves and MEL-type Pentasil molecular sieves.
[0092] "Micropore" generally refers to a pore diameter less than 2 nm.
[0093] "Mesopore" generally refers to a pore diameter in the range of 2 - 50 nm.
[0094] "Self-supporting molecular sieve" generally refers to a molecular sieve material with a micropore-mesopore structure formed by the interlaced growth and accumulation of nano-sheet molecular sieves.
Claims
1. A method for preparing a self-supporting molecular sieve of titanium species with an open structure, characterized in that: The steps include: (1) preparing a silicon source, a titanium source, an organic base and water as raw materials; (2) adding an organic base to water, stirring, and then adding a silicon source and stirring thoroughly to obtain a reaction gel; (3) placing the obtained reaction gel in a reaction kettle, sealing the reaction kettle and aging it, and then performing the first crystallization; (4) After the first crystallization, the reactor is taken out, and after cooling, a titanium source is added dropwise into the lining, and after stirring to make the reaction uniform, the reactor is sealed and a second crystallization is performed; (5) The reaction solution obtained after the secondary crystallization is centrifuged, washed with water until the reaction solution is neutral, then washed with anhydrous ethanol, and dried to obtain a molecular sieve powder. The molecular sieve powder is calcined to obtain a self-supporting molecular sieve with an open structure titanium species.
2. The method for preparing a titanium species self-supporting molecular sieve having an open structure according to claim 1, characterized in that: In step (1), the molar ratio of the silicon source, the titanium source, the organic base and water is 1.0:0.025:0.3:
30.
3. The method for preparing a titanium species self-supporting molecular sieve having an open structure according to claim 1, characterized in that: In step (3), the aging process conditions are: aging in an oven at 80°C for 2 days; the first crystallization process conditions are: crystallization in an oven at 120°C for 12 to 24 hours.
4. The method for preparing a titanium species self-supporting molecular sieve having an open structure according to claim 1, characterized in that: The secondary crystallization process conditions in step (4) are: crystallization in an oven at 120° C. for 1 to 4 days or crystallization in a microwave oven at 120° C. for 4 hours.
5. The method for preparing a titanium species self-supporting molecular sieve having an open structure according to claim 1, characterized in that: In step (5), the process conditions for calcining the molecular sieve powder are: calcining at a temperature of 550° C. for 6 hours.
6. The method for preparing a titanium species self-supporting molecular sieve having an open structure according to claim 1, characterized in that: The titanium source is at least one of titanium chloride, titanium sulfate, tetraethyl titanate, tetrabutyl titanate, isopropyl titanate, tetrabutyl titanate tetramer and ammonium hexafluorotitanate.
7. The method for preparing a titanium species self-supporting molecular sieve with an open structure according to claim 1, characterized in that: The silicon source is at least one of tetraethyl orthosilicate, silica sol, nano silicon dioxide and water glass.
8. The method for preparing a titanium species self-supporting molecular sieve with an open structure according to claim 1, characterized in that: The organic base is at least one of tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapropylammonium bromide and tetrabutylammonium bromide.
9. A titanium species self-supporting molecular sieve having an open structure prepared by the method according to any one of claims 1 to 8.
10. The titanium species self-supporting molecular sieve with an open structure as claimed in claim 9 is used as a catalyst in the epoxidation reaction of 1-octene.
Citation Information
Patent Citations
Preparation of porous crystalline synthetic material comprised of silicon and titanium oxides
US4410501A