Modification method of titanium silicalite molecular sieve TS-1, modified titanium silicalite molecular sieve TS-1 and application
Patent Information
- Application Number
- CN202510011297.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-03
- Publication Date
- 2025-05-02
AI Technical Summary
During the later cycle catalysis process, titanium silicon molecular sieve TS-1 leads to structural breakdown and titanium source loss due to aqueous phase separation, resulting in a decrease in catalytic efficiency and short service life, especially in the catalytic synthesis of vinyl sulfate.
Modified titanium silicon molecular sieve TS-1 is prepared by dispersing and mixing the titanium silicon molecular sieve TS-1 with alumina, undergoing hydrothermal reaction and calcining treatment. The adsorption of aluminum oxide allows titanium silicon molecular sieve TS-1 to be uniformly adsorbed on its surface, reducing the loss of titanium source and maintaining the stability of the physical structure.
The modified titanium silicon molecular sieve TS-1 has high catalytic efficiency, excellent stability and significantly increased service life, which makes the catalytic synthesis reaction of vinyl sulfate good stability. At the same time, the preparation method is simple and the production cost is low, which is suitable for large-scale production.
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Abstract
Description
Technical Field
[0001] The invention belongs to the field of titanium silicate molecular sieves, and specifically relates to a modification method of titanium silicate molecular sieve TS-1, a modified titanium silicate molecular sieve TS-1 and an application thereof. Background Art
[0002] Titanium silicate molecular sieve is a type of silicate zeolite containing titanium heteroatoms in the crystal framework. Among them, TS-1 is an extremely important member of the titanium silicate molecular sieve family. Titanium silicate molecular sieve TS-1 has very excellent thermal, chemical stability and mechanical strength. Its unique pore structure and the introduction of titanium give it good shape-selective catalytic activity, and it plays a positive feedback role in the shape-selective oxidation reaction of organic matter with the addition of hydrogen peroxide. Therefore, the preparation and modification of titanium silicate molecular sieve TS-1 have important research significance and are widely used in organic synthesis, catalysis and reactors. Among them, since the structure, specific surface area and morphology of titanium silicate molecular sieve TS-1 have a great influence on its catalytic activity, the study of the size, morphology and existence form of titanium species of titanium silicate molecular sieve TS-1 particles is particularly important.
[0003] At present, there have been a lot of studies on how to control the size of titanium silicalite TS-1 by controlling reaction parameters or introducing morphology modifiers during the formation of the structure of titanium silicalite TS-1. However, there are fewer studies on how to control the maintenance of the morphology of titanium silicalite TS-1 during subsequent use and catalysis. Due to the good water solubility of titanium silicalite TS-1, its physical structure is very unstable. It is prone to structural collapse and particle breakage during the process of catalytic organic synthesis in hydrogen peroxide system. Although many studies have used additives to stabilize the physical structure of titanium silicalite TS-1, the TS-1 structure is still easy to break and collapse during subsequent use and catalysis, and the separation of the water phase leads to the loss of the key catalytic component titanium source, which causes the catalytic service life of the obtained product to fail to meet the expected target.
[0004] The above problem is particularly serious in the catalytic synthesis of dithiothreitol (DTD). In the past, people usually used the template agent tetrapropylammonium hydroxide (TPAOH) to improve the structure of TS-1, but this method is expensive and the synthesis process is complicated, which is not conducive to large-scale production.
[0005] In short, in the later cycle catalytic process, the titanium silicalite TS-1 is affected by the separation of the water phase, resulting in serious structural fragmentation and titanium source loss. Especially in the catalytic synthesis process of vinyl sulfate, its stability is insufficient. After repeated use, the catalytic efficiency decreases and the catalytic service life is short. Summary of the invention
[0006] The first object of the present invention is to provide a modification method of titanium silicate molecular sieve TS-1, which is used to solve the problems of insufficient stability, reduced catalytic efficiency and short catalytic service life of titanium silicate molecular sieve TS-1 in the catalytic synthesis process of vinyl sulfate in the prior art.
[0007] The second object of the present invention is to provide a modified titanium silicalite TS-1 obtained by the above modification method.
[0008] The third object of the present invention is to provide the use of the modified titanium silicalite TS-1 in the catalytic synthesis of vinyl sulfate.
[0009] To achieve the above first purpose, the technical solution adopted by the present invention is:
[0010] A modification method of titanium silicate molecular sieve TS-1 comprises the following steps:
[0011] (1) mixing titanium silicate TS-1, alumina, ethanol and water to obtain a mixed solution; the mass ratio of the titanium silicate TS-1 to the alumina is 1:(0.1-2);
[0012] (2) subjecting the mixed solution to a hydrothermal reaction at 100 to 300° C. to obtain a hydrothermal product;
[0013] (3) calcining the hydrothermal product at 400-600°C to obtain modified TS-1.
[0014] The present invention is a pioneering invention, in which modified titanium silicon molecular sieve TS-1 is prepared by dispersing and mixing titanium silicon molecular sieve TS-1 and aluminum oxide, and then undergoing hydrothermal reaction treatment and calcination treatment. Aluminum oxide has a good adsorption effect and does not react with other substances in the catalytic reaction; at the same time, aluminum oxide also uniformly and effectively adsorbs titanium silicon molecular sieve TS-1 on the surface, so that the titanium source of titanium silicon molecular sieve TS-1 is not easy to lose, and the physical structure of titanium silicon molecular sieve TS-1 is stable in the process of catalytic organic synthesis, and it is not easy to collapse the structure and break the particles.
[0015] The modified titanium silicalite TS-1 has high catalytic efficiency, excellent stability and increased service life, which makes the catalytic synthesis reaction of vinyl sulfate stable. At the same time, the preparation method is simple in process, low in production cost and easy to realize large-scale production.
[0016] Preferably, the mass ratio of titanium silicalite TS-1 to alumina in step (1) is 1:(1-1.2). Under this preferred ratio, the catalytic efficiency of the unmodified titanium silicalite TS-1 can be increased from 5 catalytic cycles to less than 80% and still maintain more than 85% after 15 catalytic cycles.
[0017] More preferably, the mass ratio of titanium silicalite TS-1, ethanol and water is 50:(100-200):(110-150).
[0018] Preferably, the particle size of the aluminum oxide is 4 to 20 μm.
[0019] Preferably, the hydrothermal reaction time is 1 to 10 hours. Under the above conditions, aluminum oxide can more easily adsorb titanium silicon molecular sieve TS-1, and titanium silicon molecular sieve TS-1 is uniformly, dispersedly and stably attached to the surface of aluminum oxide, thereby improving the catalytic efficiency of titanium silicon molecular sieve TS-1.
[0020] Preferably, the calcination time is 1 to 10 hours. Under the above conditions, the adsorption of titanium silicon molecular sieve TS-1 and alumina can be more stable, thereby improving the catalytic stability of titanium silicon molecular sieve TS-1.
[0021] In order to achieve the above second purpose, the technical solution adopted by the present invention is:
[0022] The modified titanium silicalite TS-1 is obtained by the modification method of the titanium silicalite TS-1.
[0023] The modified titanium silicalite TS-1 obtained by the modification method of the titanium silicalite TS-1 has a stable material structure and high catalytic efficiency; it can be recycled in the reaction of catalytic synthesis of vinyl sulfate, significantly improving the service life of TS-1.
[0024] In order to achieve the third purpose above, the technical solution adopted by the present invention is:
[0025] The modified titanium silicalite TS-1 is used in the catalytic synthesis of vinyl sulfate.
[0026] In the cyclic catalytic synthesis reaction of vinyl sulfate, the modified titanium silicate TS-1 material has a stable structure and a longer catalytic service life. TEM results show that TS-1 particles are tightly adsorbed on the surface of the alumina carrier, the loss of titanium source is reduced, and the structural stability is high, thus realizing the construction of long-life titanium silicate TS-1. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 This is a SEM characterization image of the modified titanium silicalite TS-1 prepared in Example 1;
[0028] Figure 2 This is a SEM characterization image of the modified titanium silicalite TS-1 prepared in Example 2;
[0029] Figure 3 This is a SEM characterization image of the modified titanium silicalite TS-1 prepared in Example 3;
[0030] Figure 4This is a SEM characterization image of the modified titanium silicon molecular sieve TS-1 prepared in Comparative Example 1;
[0031] Figure 5 This is the SEM characterization image of the modified titanium silicalite TS-1 prepared in Comparative Example 2. DETAILED DESCRIPTION
[0032] The technical concept of the present invention is to construct a composite catalytic system of titanium silicon molecular sieve TS-1 and aluminum oxide, and improve the structural stability by combining hydrothermal reaction and calcination. During the modification process, the titanium silicon molecular sieve TS-1 particles are firmly and tightly attached to the surface of aluminum oxide, which minimizes the loss of titanium source and ensures the realization of the catalytic performance of TS-1.
[0033] The relative amount and particle size of titanium silicate molecular sieve TS-1 and alumina determine the morphological structure of the modified titanium silicate molecular sieve. Too little alumina will result in a loose composite of TS-1 particles, which will easily scatter and flow away during the later catalytic process, leading to a decrease in catalytic performance. Too much alumina will result in low efficiency of alumina use and reduce the effective contact area of the catalytic reaction system, which will also affect the catalytic efficiency of subsequent reactions.
[0034] Conventional TS-1 products are spherical structures formed by the accumulation of fine particles of 100-300nm. In the reaction of catalytic synthesis of vinyl sulfate, the catalytic efficiency drops to below 80% after 5 uses. The modified TS-1 obtained by the above method has a significantly extended service life. The product under some preferred conditions still maintains a catalytic efficiency of more than 85% after 15 uses.
[0035] The implementation process of the present invention is described in detail below in conjunction with specific examples. The particle size of the aluminum oxide used in the following examples is 4 to 20 μm.
[0036] 1. Modification method of titanium silicate molecular sieve TS-1 of the present invention and specific embodiment of modified titanium silicate molecular sieve TS-1
[0037] Example 1
[0038] The modification method of the titanium silicate molecular sieve TS-1 of this embodiment comprises the following steps:
[0039] (1) Weigh 50 g of titanium silicalite TS-1 into a beaker, add 200 g of water, stir and mix, then add 50 g of alumina and 125 g of ethanol and mix well to obtain a mixed slurry.
[0040] (2) The mixed slurry obtained in step (1) is placed in a hydrothermal reactor with a filling degree of 70% of the total volume of the reactor, and reacted at 150° C. for 4 hours; after the hydrothermal reactor is cooled, it is opened and placed in a vacuum drying oven at 100° C. to dry to obtain a hydrothermal product. In other embodiments, the filling degree can be between 60% and 80%, for example, 60%, 75%, 80%, etc.
[0041] (3) The hydrothermal product obtained in step (2) is placed in a muffle furnace and calcined at 550° C. in an air atmosphere for 2 h to obtain the modified titanium silicon molecular sieve TS-1.
[0042] Example 2
[0043] The modification method of the titanium silicate molecular sieve TS-1 of this embodiment comprises the following steps:
[0044] (1) Weigh 50 g of titanium silicalite TS-1 into a beaker, add 100 g of water, stir and mix, then add 50 g of alumina and 111 g of ethanol and mix well to obtain a mixed slurry.
[0045] (2) The mixed slurry obtained in step (1) is placed in a hydrothermal reactor with a filling degree of 70% of the total volume of the reactor, and reacted at 100° C. for 1 hour; after the hydrothermal reactor is cooled, it is opened and placed in a vacuum drying oven at 100° C. for drying to obtain a hydrothermal product.
[0046] (3) The hydrothermal product obtained in step (2) was placed in a muffle furnace and calcined at 400° C. in an air atmosphere for 1 h to obtain the modified titanium silicon molecular sieve TS-1.
[0047] Example 3
[0048] The modification method of the titanium silicate molecular sieve TS-1 of this embodiment comprises the following steps:
[0049] (1) Weigh 50 g of titanium silicalite TS-1 and place it in a beaker, add 150 g of water, stir and mix, then add 50 g of alumina and 150 g of ethanol and mix well to obtain a mixed slurry.
[0050] (2) The mixed slurry obtained in step (1) is placed in a hydrothermal reactor with a filling degree of 70% of the total volume of the reactor, and reacted at 300° C. for 10 h; after the hydrothermal reactor is cooled, it is opened and placed in a vacuum drying oven at 100° C. for drying to obtain a hydrothermal product.
[0051] (3) The hydrothermal product obtained in step (2) was placed in a muffle furnace and calcined at 600° C. in an air atmosphere for 10 h to obtain the modified titanium silicon molecular sieve TS-1.
[0052] 2. Comparison
[0053] Comparative Example 1
[0054] The modification method of titanium silicalite TS-1 in Comparative Example 1 is different from that in Example 1 only in that: in step (1), 50 g of titanium silicalite TS-1 is weighed and placed in a beaker, 200 g of water is added, and the mixture is stirred and mixed, and then 5 g of alumina and 125 g of ethanol are added and mixed evenly to obtain a mixed slurry.
[0055] Comparative Example 2
[0056] The modification method of titanium silicalite TS-1 in Comparative Example 2 is different from that in Example 1 only in that: in step (1), 50 g of titanium silicalite TS-1 is weighed and placed in a beaker, 200 g of water is added, and the mixture is stirred and mixed, and then 100 g of alumina and 125 g of ethanol are added and mixed evenly to obtain a mixed slurry.
[0057] Comparative Example 3
[0058] The modification method of titanium silicalite TS-1 in Comparative Example 1 is different from that in Example 1 only in that: in step (1), 50 g of titanium silicalite TS-1 is weighed and placed in a beaker, 200 g of water is added, and the mixture is stirred and mixed, and then 20 g of alumina and 125 g of ethanol are added and mixed evenly to obtain a mixed slurry.
[0059] Comparative Example 4
[0060] The modification method of titanium silicalite TS-1 in Comparative Example 1 is different from that in Example 1 only in that: in step (1), 50 g of titanium silicalite TS-1 is weighed and placed in a beaker, 200 g of water is added, and the mixture is stirred and mixed, and then 80 g of alumina and 125 g of ethanol are added and mixed evenly to obtain a mixed slurry.
[0061] Comparative Example 5
[0062] The titanium silicate molecular sieve TS-1 of Comparative Example 5 is an unmodified titanium silicate molecular sieve TS-1.
[0063] 3. Experimental Examples
[0064] Experimental Example 1 SEM Analysis
[0065] The modified titanium silicon molecular sieve TS-1 prepared according to Examples 1 to 3 and Comparative Examples 1 to 2 was characterized using SEM, and the results are shown in Figure 1 to Figure 5 shown.
[0066] The unmodified TS-1 product is a spherical product composed of 100-300nm fine particles. Due to its structural instability in aqueous solution, the spheres will break. Therefore, the stability of the modified TS-1 product can be judged by the presence of fine particles and the distribution density of TS-1 particles on the alumina surface.
[0067] Figure 1No large amount of TS-1 particles were found scattered, and the fine particles of TS-1 were all adsorbed on the surface of alumina. The utilization rate of the alumina surface was high, and there was no large amount of exposed surface that would cause waste of raw materials. Figure 2-3 In the middle, the surface of alumina is tightly adsorbed by TS-1 fine particles.
[0068] Comparative Example 1 corresponds to Figure 4 In the process, due to the small amount of alumina used, a large number of TS-1 fine particles were scattered, which is also an important reason for the loss of titanium source, structural damage and shortened service life of TS-1 catalyst.
[0069] Comparative Example 2 corresponds to Figure 5 In the process, no large amount of TS-1 particles were found to be scattered, and the fine particles of TS-1 were all adsorbed on the surface of alumina. However, the utilization rate of the alumina surface was low, and a large amount of exposed surface resulted in a waste of alumina raw materials. In addition, too much alumina would still affect the catalytic efficiency of the catalytic reaction system, and thus affect the service life of the catalyst.
[0070] Experimental Example 2 Application of modified titanium silicalite TS-1 in catalytic synthesis of vinyl sulfate
[0071] The modified titanium silicalite TS-1 prepared in Examples 1 to 3 and Comparative Examples 1 to 4, and Comparative Example 5 (unmodified raw titanium silicalite TS-1) were used as catalysts in the reaction of catalyzing the synthesis of vinyl sulfate (DTD) from vinyl sulfite (ES).
[0072] Specifically, 12 g of titanium silicalite TS-1 was added to a mixture of 16.2 g of ES and 600 mL of DCM (dichloromethane), stirred at 25 °C for 6 hours, filtered, concentrated the filtrate and dried, and the mass of the finished product was weighed.
[0074] After drying the water content of the filtered cake, i.e., titanium silicon molecular sieve TS-1, the next batch of catalytic synthesis of DTD is continued, and the catalytic efficiency of each batch is recorded in turn. In each subsequent batch of catalytic synthesis reactions, the amount of ES and DCM and the reaction conditions remain consistent. The catalytic efficiency of titanium silicon molecular sieve TS-1 in each embodiment and comparative example is shown in Table 1 below.
[0075] Table 1: Use cycle and catalytic efficiency of Examples 1 to 3 and Comparative Examples 1 to 5
[0076]
[0077]
[0078]
[0079] As can be seen from Table 1, in Example 1, when the modified titanium silicon molecular sieve TS-1 is used for 15 times, the catalytic efficiency is still maintained at more than 85%; in Example 2 and Example 3, when the modified titanium silicon molecular sieve TS-1 is used for 5 times, the catalytic efficiency is still maintained at more than 82%. The catalytic efficiency of the modified titanium silicon molecular sieve TS-1 of Comparative Examples 1 to 4 is still improved to a certain extent compared with the unmodified TS-1 of Comparative Example 5 after the use cycle reaches 5 times.
[0080] In general, Example 1 can reduce the service life of TS-1 from 5 catalytic times to less than 80% and increase it to more than 85% after 15 catalytic times, significantly extending the service life of TS-1, which is extremely beneficial to reducing the production cost of enterprises. In addition, this method has the characteristics of simple operation, high product quality, mild conditions, short preparation cycle, and suitability for large-scale production, and can well solve the problems of easy breakage and collapse of TS-1 structure, loss of titanium source, and short catalytic service life.
[0081] The above is a detailed description of the embodiment process, but it does not limit the technical solution of the present invention. Ordinary technicians in this field should understand that any modifications, partial replacements and variations can be made to the above-mentioned embodiments within the scope of the present invention, which should all be included in the required scope of the present invention.
Claims
1. A modification method of titanium silicon molecular sieve TS-1, characterized in that: The following steps are involved: (1) mixing titanium silicate TS-1, alumina, ethanol and water to obtain a mixed solution; the mass ratio of the titanium silicate TS-1 to the alumina is 1:(0.1-2); (2) subjecting the mixed solution to a hydrothermal reaction at 100 to 300° C. to obtain a hydrothermal product; (3) calcining the hydrothermal product at 400-600°C to obtain modified TS-1.
2. The modification method of titanium silicon molecular sieve TS-1 according to claim 1, characterized in that: Step (1) The mass ratio of titanium silicon molecular sieve TS-1 to alumina is 1: (1-1.2).
3. The modification method of titanium silicon molecular sieve TS-1 according to claim 2, characterized in that: The mass ratio of titanium silicalite TS-1, ethanol and water is 50: (100-200): (110-150).
4. The modification method of titanium silicon molecular sieve TS-1 according to claim 1, 2 or 3, characterized in that: The particle size of the aluminum oxide is 4 to 20 μm.
5. The modification method of titanium silicalite TS-1 according to claim 1, characterized in that: The hydrothermal reaction time is 1 to 10 hours.
6. The modification method of titanium silicate molecular sieve TS-1 according to claim 1, characterized in that: The calcination time is 1 to 10 hours.
7. A modified titanium silicalite TS-1 obtained by the modification method of titanium silicalite TS-1 as claimed in any one of claims 1 to 6.
8. Use of the modified titanium silicalite TS-1 as claimed in claim 7 in catalytic synthesis of vinyl sulfate.