Titanium silicalite / glass bead composite material, preparation method and application thereof

Abstract

The application relates to the technical field of catalysts, in particular to a titanium-silicon molecular sieve / glass bead composite material and a preparation method and application thereof. The preparation method of the titanium-silicon molecular sieve / glass bead composite material comprises the following steps: placing a titanium-silicon molecular sieve mother liquor and glass beads into a micro reaction device with an equivalent diameter of 1.6mm-16mm, heating the micro reaction device, crystallizing the titanium-silicon molecular sieve mother liquor, loading the titanium-silicon molecular sieve on the surface of the glass beads, and preparing the titanium-silicon molecular sieve / glass bead composite material. The preparation method provided by the application can shorten the growth cycle, and the titanium-silicon molecular sieve / glass bead composite material prepared by the method has more uniform particle size.

Description

Technical Field

[0001] This application relates to the field of catalyst technology, and in particular to a titanium-silicon molecular sieve / glass microsphere composite material, its preparation method, and its application. Background Technology

[0002] Titanium silicate molecular sieve, abbreviated as TS-1, is a type of ZSM-5 series molecular sieve in which titanium replaces aluminum in silica-alumina molecular sieves. It has an MFI topology and a two-dimensional ten-membered ring channel system. Its sinusoidal channel diameter along the (100) direction is 0.51 nm × 0.55 nm, and its straight channel diameter along the (010) direction is 0.53 nm × 0.56 nm. Due to its special channel structure and the introduction of titanium atoms, the oxidation system formed by titanium silicate molecular sieve and hydrogen peroxide has the advantages of mild reaction conditions and green and environmentally friendly oxidation process. Therefore, it can be widely used as a catalyst in the oxidation of alkanes, the epoxidation of alkenes, the oxidation of alcohols, the oxime reaction of ketones, and the hydroxylation reaction of phenols. It is a heteroatom molecular sieve catalyst with excellent catalytic performance and high selectivity.

[0003] However, traditional methods of directly reacting titanium-silicon molecular sieve nanoparticles in stainless steel crystallization reactors using silicon and titanium sources present several problems: First, due to their high surface energy, titanium-silicon molecular sieve nanoparticles easily agglomerate into micron-sized particles during practical use. For example, even under ultrasonic stirring conditions, titanium-silicon molecular sieve nanoparticles with an average particle size of only 350 nm will still agglomerate into particles with an average particle size of 425 μm in the reaction solvent, leading to reduced catalytic activity. Second, the separation and recovery of titanium-silicon molecular sieve nanoparticles after the reaction is difficult. Currently, membrane filtration is the main method for separating nanoparticles from the reaction system, but after a few uses, the membrane pores are easily clogged, rendering the entire separation membrane unusable. Membrane replacement costs account for a significant proportion of the overall process cost. Furthermore, using a crystallization reactor for the reaction results in a long growth cycle (6–30 days) for titanium-silicon molecular sieve nanoparticles, uneven particle size, and high costs. Summary of the Invention

[0004] Therefore, it is necessary to provide a titanium-silicon molecular sieve / glass microsphere composite material that can shorten the growth cycle and has a more uniform particle size, as well as its preparation method and application.

[0005] In a first aspect, this application provides a method for preparing a titanium-silicon molecular sieve / glass microsphere composite material, comprising the following steps:

[0006] The titanium-silicon molecular sieve mother liquor and glass microspheres are placed in a micro-reaction device with an equivalent diameter of 1.6 mm to 16 mm. The micro-reaction device is heated to liquidate the titanium-silicon molecular sieve mother liquor and load the titanium-silicon molecular sieve onto the surface of the glass microspheres, thereby preparing the titanium-silicon molecular sieve / glass microsphere composite material.

[0007] In some embodiments, the microreactor is a closed tubular channel;

[0008] And / or, the microreactor is made of metal.

[0009] In some embodiments, the mass ratio of the glass microspheres to the mother liquor of the titanium-silicon molecular sieve is 1:(1-5);

[0010] And / or, the particle size of the glass microspheres is 70 μm to 150 μm.

[0011] In some embodiments, the titanium-silicon molecular sieve mother liquor includes a titanium source, a silicon source, a template agent, and water;

[0012] Optionally, the molar ratio of the titanium source to the silicon source is 1:(0.01~1);

[0013] Optionally, the molar ratio of the template agent to the silicon source is 1:(0.1 to 0.7);

[0014] Optionally, the molar ratio of the silicon source to the water is 1:(50-100).

[0015] In some embodiments, the preparation method satisfies at least one of the following characteristics:

[0016] 1) The titanium source includes one or more of tetraethyl titanate, tetrabutyl titanate, and titanium tetrachloride;

[0017] 2) The silicon source includes tetraethyl orthosilicate and / or silica sol;

[0018] 3) The template agent includes one or more of tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and piperidine quaternary ammonium hydroxide.

[0019] In some embodiments, the titanium-silicon molecular sieve mother liquor is prepared by a method comprising the following steps:

[0020] The titanium source is dissolved in an organic solvent to prepare an organic solution containing the titanium source;

[0021] The template agent, the silicon source, the titanium-containing organic solution, and water are mixed, aged, and the organic solvent is removed to prepare the titanium-silicon molecular sieve mother liquor.

[0022] In some embodiments, the preparation method satisfies at least one of the following characteristics:

[0023] 1) The organic solvents include alcohol solvents and / or alkane solvents;

[0024] 2) The aging temperature is 20℃~80℃, and the time is 3h~24h;

[0025] 3) The molar ratio of the organic solvent to the titanium source is 1:(0.001~0.003);

[0026] 4) The method for removing the organic solvent is heating, wherein the heating temperature is 60℃~95℃ and the heating time is 10min~45min.

[0027] In some embodiments, after heating the microreactor, the method further includes: calcining the heated material to remove the template agent;

[0028] Optionally, the calcination temperature is 550℃~600℃, and the time is 5h~8h.

[0029] In some embodiments, the heating temperature for heating the microreactor is 100°C to 170°C, and the heating time is 0.1h to 24h.

[0030] In some embodiments, before placing the glass microspheres into the microreactor, the process further includes etching, acid washing, water washing, drying, and calcining the glass microspheres with subcritical water.

[0031] Optionally, the pickling step includes: immersing the glass microspheres in an inorganic acid with a concentration of 0.5M to 1.0M for 5 hours to 8 hours;

[0032] Optionally, the water flow rate for the washing is 3 mL / min to 5 mL / min, and the time is 5 h to 8 h;

[0033] Optionally, the drying temperature is 80℃~120℃;

[0034] Optionally, the calcination temperature is 400℃~600℃ and the time is 3h~6h.

[0035] Secondly, this application provides a titanium-silicon molecular sieve / glass microsphere composite material, which is prepared by the preparation method described in the first aspect.

[0036] In some embodiments, the titanium-silicon molecular sieve / glass microsphere composite material is composed of nanoparticles, wherein the titanium-silicon molecular sieve in the titanium-silicon molecular sieve / glass microsphere composite material is composed of nanoparticles, and the average particle size of the nanoparticles is 190 nm to 240 nm.

[0037] Thirdly, this application provides an application of the titanium-silicon molecular sieve / glass microsphere composite material as described in the second aspect as a catalyst.

[0038] The method for preparing titanium-silicon molecular sieve / glass microsphere composite materials provided in this application employs a micro-reactor (equivalent diameter ≤ 16 mm). Compared to the traditional hydrothermal crystallization reactor, the micro-reactor with a specific equivalent diameter exhibits superior heat transfer performance, significantly improving the heating rate. This shortens the induction period, accelerates the nucleation process of the titanium-silicon molecular sieve, and consequently shortens the growth cycle of the composite material (at least as low as 0.1 h). The reduced particle size of the titanium-silicon molecular sieve further shortens the internal diffusion mass transfer path between reactants and products, improving mass transfer efficiency and reaction rate. Furthermore, the micro-reactor promotes heterogeneous nucleation of the titanium-silicon molecular sieve mother liquor, preventing homogeneous nucleation. This ensures uniform loading of the titanium-silicon molecular sieve onto the surface of the glass microspheres, avoiding agglomeration and significantly improving raw material utilization, enhancing catalytic performance, and drastically reducing wastewater and waste generation.

[0039] Furthermore, the small size of the microreactor allows for a very narrow temperature and concentration gradient within it, resulting in more uniform overall crystallization conditions. This ensures a high degree of consistency in the growth process of the titanium-silicon molecular sieve and guarantees the uniformity of particle size in composite materials produced in different batches, thus resulting in excellent catalytic performance.

[0040] In summary, the preparation method provided in this application has the advantages of short growth cycle, high production efficiency, low cost and high batch stability, and the resulting composite material has a more uniform particle size. Attached Figure Description

[0041] Figure 1 This is a scanning electron microscope (SEM) image of the glass microsphere carrier after etching in Example 1;

[0042] Figure 2 This is a scanning electron microscope image of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in Example 1;

[0043] Figure 3 This is a scanning electron microscope image of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in Example 2;

[0044] Figure 4This is a scanning electron microscope image of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in Example 3;

[0045] Figure 5 This is a scanning electron microscope image of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in Example 4;

[0046] Figure 6 This is a scanning electron microscope image of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in Example 5;

[0047] Figure 7 This is a scanning electron microscope image of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in Example 6;

[0048] Figure 8 The image shows a scanning electron microscope (SEM) image of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in Comparative Example 1. Detailed Implementation

[0049] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0051] the term:

[0052] As used herein, the term "and / or" encompasses any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" includes three parallel options: A, B, and "a combination of A and B".

[0053] In this document, unless otherwise stated, "one or more" means any one of the listed items or any combination of the listed items. Similarly, "one or more" and other instances of "one or more" are to be understood in the same way unless otherwise stated.

[0054] In this document, terms such as "further," "even further," "especially," "for example," "as," "example," and "exemplary" are used for descriptive purposes to indicate a connection in the coverage of different technical solutions presented earlier and later. However, they should not be construed as limitations on the preceding technical solution or on the scope of protection of this document. Unless otherwise specified, A (as in B) indicates that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0055] In this document, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "present" or "absent." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. In this application, descriptions such as "optionally contains" and "optionally includes" indicate "contains or does not contain." "Optional component X" indicates whether component X exists or does not exist, or whether component X is contained or not.

[0056] In this document, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth" serve only as a non-exhaustive enumeration and should be understood as not constituting a closed limitation on quantity.

[0057] In this article, the technical features described in an open-ended manner include both closed technical solutions composed of the listed features and open technical solutions that include the listed features.

[0058] In this document, when referring to numerical intervals (i.e., numerical ranges), unless otherwise specified, the distribution of selectable values ​​within a numerical interval is considered continuous, and includes the two endpoints (i.e., the minimum and maximum values) of the numerical interval, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in this numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, and other numerical interval types.

[0059] In this document, the terms "room temperature" or "normal temperature" generally refer to 4°C to 35°C, for example, 20°C ± 5°C. In some embodiments of this document, "room temperature" or "normal temperature" refers to 10°C to 30°C. In some embodiments of this document, "room temperature" or "normal temperature" refers to 20°C to 30°C.

[0060] In this document, for methods involving multiple steps, unless otherwise explicitly stated herein, there is no strict order constraint on the execution of these steps; they may be executed in any order other than those described. Moreover, any step may include multiple sub-steps or multiple stages, which are not necessarily completed at the same time, but may be executed at different times, and their execution order is not necessarily sequential, but may be executed in turn, alternately, or simultaneously with other steps or parts of the sub-steps or stages of other steps.

[0061] Traditional titanium-silicon molecular sieve nanoparticles obtained by directly reacting silicon and titanium sources in a stainless steel hydrothermal crystallization reactor suffer from drawbacks such as easy agglomeration, uneven size, poor catalytic activity, high cost, and long growth cycle. Therefore, this application provides a method for preparing titanium-silicon molecular sieve / glass microsphere composite materials to avoid these defects and improve the catalytic performance of titanium-silicon molecular sieves.

[0062] In a first aspect, this application provides a method for preparing a titanium-silicon molecular sieve / glass microsphere composite material, comprising the following steps:

[0063] The titanium-silicon molecular sieve mother liquor and glass microspheres are placed in a micro-reaction device with an equivalent diameter of 1.6 mm to 16 mm. The micro-reaction device is heated to liquidate the titanium-silicon molecular sieve mother liquor and load the titanium-silicon molecular sieve onto the surface of the glass microspheres, thereby preparing the titanium-silicon molecular sieve / glass microsphere composite material.

[0064] The method for preparing titanium-silicon molecular sieve / glass microsphere composite materials provided in this application employs a micro-reactor (equivalent diameter ≤ 16 mm). Compared to the traditional hydrothermal crystallization reactor, the micro-reactor with a specific equivalent diameter exhibits superior heat transfer performance, significantly improving the heating rate. This shortens the induction period, accelerates the nucleation process of the titanium-silicon molecular sieve, and consequently shortens the growth cycle of the composite material (at least as low as 0.1 h). The reduced particle size of the titanium-silicon molecular sieve further shortens the internal diffusion mass transfer path between reactants and products, improving mass transfer efficiency and reaction rate. Furthermore, the micro-reactor promotes heterogeneous nucleation of the titanium-silicon molecular sieve mother liquor, preventing homogeneous nucleation. This ensures uniform loading of the titanium-silicon molecular sieve onto the surface of the glass microspheres, avoiding agglomeration and significantly improving raw material utilization, enhancing catalytic performance, and drastically reducing wastewater and waste generation.

[0065] Furthermore, the small size of the microreactor allows for a very narrow temperature and concentration gradient within it, resulting in more uniform overall crystallization conditions. This ensures a high degree of consistency in the growth process of the titanium-silicon molecular sieve and guarantees the uniformity of particle size in composite materials produced in different batches, thus resulting in excellent catalytic performance.

[0066] In summary, the preparation method provided in this application has the advantages of short growth cycle, high production efficiency, low cost and high batch stability, and the resulting composite material has a more uniform particle size.

[0067] To avoid the problems of easy agglomeration and membrane pore blockage during separation caused by traditionally prepared titanium-silicon molecular sieves, researchers have proposed granulation or loading methods to prepare titanium-silicon molecular sieves, for example, using cordierite or carbon nanofibers as supports. However, granulation methods prevent the internal particles of the titanium-silicon molecular sieve from participating in the catalytic process, resulting in low utilization. Furthermore, the bonding force between the aforementioned supports and the titanium-silicon molecular sieve is poor, easily leading to detachment. Moreover, the specific surface area of ​​currently used supports is small, making it difficult to provide sufficient heterogeneous nucleation sites for the titanium-silicon molecular sieve mother liquor, resulting in low loading and significant homogeneous nucleation of the mother liquor, causing waste and generating large amounts of polluting wastewater. This application uses glass microspheres as a support, allowing the titanium-silicon molecular sieve to exist only on the surface of the glass microspheres, thus completely solving the problem of the internal titanium-silicon molecular sieve's inability to participate in catalysis.

[0068] In this application, crystallization specifically refers to heated static crystallization, that is, keeping the micro-reaction device in a static state during the heating process.

[0069] It is understood that equivalent diameter can be used to compare the size and shape similarity of different shapes; when equivalent diameters are similar, it indicates that their sizes (volume, area) are similar. In this application, equivalent diameter refers to the inner diameter of the microreactor. In some embodiments, the equivalent diameter of the microreactor can be any value between 1.6 mm and 16 mm, for example, 2 mm, 3 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, and 14 mm.

[0070] In this application, the shape of the microreactor is not limited. For example, it can be a closed tubular channel, wherein the cross-section of the tubular channel can be circular or polygonal, such as square, rectangle, hexagon, etc., preferably circular. That is, the tubular channel is a cylindrical channel, which allows it to have the largest specific surface area, further improving the heat transfer performance of the microreactor and increasing its heating rate.

[0071] To improve heat transfer performance, the microreactor in this application is made of metal, such as stainless steel. Specifically, the stainless steel can be 304 stainless steel or 316 stainless steel.

[0072] Furthermore, the micro-reaction device is a stainless steel liquid chromatography column, both ends of which can be sealed with nuts.

[0073] In this application, the size of the glass microspheres is not limited, and commonly used commercially available sizes of glass microspheres can be selected. In some embodiments, the particle size of the glass microspheres is 70μm to 150μm, for example, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, and 140μm.

[0074] In some embodiments, the mass ratio of glass microspheres to the mother liquor of titanium-silicon molecular sieve is 1:(1-5), for example, 1:1, 1:3, or 1:5. By controlling the mass ratio of glass microspheres to the mother liquor of titanium-silicon molecular sieve within the above range, the loading of titanium-silicon molecular sieve on the surface of glass microspheres can be ensured.

[0075] It should be noted that in this application, the titanium silicon molecular sieve is loaded onto the surface of glass microspheres in the form of spherical crystals.

[0076] In some embodiments, the mother liquor for titanium-silicon molecular sieves includes a titanium source, a silicon source, a template agent, and water. It is understood that the "water" used in this application can specifically be deionized water, distilled water, pure water, or ultrapure water. In this application, the types of titanium source, silicon source, and template agent are not limited; any substance known in the field of titanium-silicon molecular sieve preparation can be selected. In some embodiments, the titanium source includes one or more of tetraethyl titanate, tetrabutyl titanate, and titanium tetrachloride; the silicon source includes tetraethyl orthosilicate and / or silica sol; and the template agent includes one or more of tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and piperidine quaternary ammonium hydroxide.

[0077] Furthermore, the molar ratio of titanium source to silicon source is 1:(0.01~1), for example, 1:0.05, 1:0.1, 1:0.2, 1:0.5, 1:0.8; the molar ratio of template agent to silicon source is 1:(0.1~0.7), for example, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6; and the molar ratio of silicon source to water is 1:(50~100), for example, 1:60, 1:70, 1:80, 1:90.

[0078] It should be noted that the molar ratio of silicon source to water is calculated based on the total amount of water in the template agent and water added during the removal of organic solvents.

[0079] It is understood that the preparation method of the titanium-silicon molecular sieve mother liquor can employ commonly used preparation processes. As an example, the titanium-silicon molecular sieve mother liquor is prepared using a method comprising the following steps:

[0080] A titanium source is dissolved in an organic solvent to prepare an organic solution containing the titanium source;

[0081] The template agent, silicon source, titanium-containing organic solution and water are mixed, aged, and the organic solvent is removed to prepare the titanium-silicon molecular sieve mother liquor.

[0082] Furthermore, the specific steps for mixing the template agent, silicon source, titanium-containing organic solution and water can be as follows: first, mix the template agent with water to form a template agent solution, and then add the silicon source and titanium-containing organic solution to the template agent solution.

[0083] Furthermore, template agent solutions can be purchased commercially; for example, the template agent can be a 25% tetrapropylammonium hydroxide solution.

[0084] In this application, the choice of organic solvent is not limited, as long as it can dissolve the titanium source and has volatile properties. In some embodiments, the organic solvent includes alcohol solvents and / or alkane solvents; wherein, alcohol solvents include, but are not limited to, one or more of isopropanol, ethanol, n-butanol and tert-butanol; alkane solvents include, but are not limited to, one or more of n-hexane, isohexane and n-heptane.

[0085] Furthermore, the molar ratio of the organic solvent to the titanium source is 1:(0.001~0.003).

[0086] In this application, the aging conditions are not limited, and commonly used process parameters in the field of titanium-silicon molecular sieve mother liquor preparation can be selected. In some embodiments, the aging temperature is 20℃~80℃ and the time is 3h~24h; preferably, the aging temperature is 40℃~60℃ and the time is 5h~8h.

[0087] In this application, the method for removing organic solvents is not limited, as long as the organic solvents can be removed as completely as possible. In some embodiments, the method for removing organic solvents is heat treatment; wherein the temperature of the heat treatment can be 60°C to 95°C, and the time can be 10 min to 45 min.

[0088] It should be noted that the quality of the mother liquor will change during the removal of organic solvents. To avoid this change, water can be added intermittently during the removal process.

[0089] In this application, there are no limitations on the methods or apparatus used to heat the microreactor. As an example, the microreactor is placed in a homogeneous reactor for heating.

[0090] In some embodiments, the heating temperature for heating the microreactor is 100°C to 170°C, and the heating time is 0.1 h to 24 h. That is, the crystallization temperature is 100°C to 170°C, and the time is 0.1 h to 24 h.

[0091] In some embodiments, after heating the microreactor, the process further includes separating, washing, and drying the materials obtained after heating.

[0092] The separation method can be centrifugation; the number of washing cycles is not limited, as long as unreacted substances are removed; the drying temperature can be 80℃~120℃.

[0093] In some embodiments, after drying the heated material, the method further includes a step of calcining the dried material to remove the template agent.

[0094] Optionally, the roasting temperature is 550℃~600℃ and the time is 5h~8h.

[0095] In some embodiments, before placing the glass microspheres within the microreactor, a step of etching the glass microspheres using subcritical water is included. This etching process increases the adhesion sites on the surface of the glass microspheres, thereby facilitating the loading of titanium-silicon molecular sieves onto the surface of the glass microspheres.

[0096] It is understandable that subcritical water refers to liquid water with a temperature of 250℃ to 310℃.

[0097] In some embodiments, the method further includes a first water wash of the etched glass microspheres to bring the pH to 7, and a first drying of the glass microspheres after the first water wash.

[0098] In some embodiments, after etching the glass microspheres, the process further includes:

[0099] The etched glass microspheres are subjected to acid washing, water washing, drying and calcination in sequence.

[0100] The specific steps of pickling, washing, drying, and calcination can be as follows:

[0101] 1) After acid washing, the glass microspheres are washed a second time with water and dried a second time;

[0102] 2) The glass microspheres after the first drying are then subjected to a third water wash, a third drying, and calcination.

[0103] In some embodiments, the pickling step includes immersing the glass microspheres in an inorganic acid with a concentration of 0.5M to 1.0M for 5 hours to 8 hours; wherein, the choice of inorganic acid is not limited, for example, it can be one or more of hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid.

[0104] Understandably, the second wash is to remove excess inorganic acid, aiming to bring the pH of the glass microspheres down to 7.

[0105] In this application, the water used for the third rinse is flowing water. In some embodiments, the water flow rate for the third rinse is 3 mL / min to 5 mL / min, and the time is 5 h to 8 h.

[0106] In some embodiments, the temperatures for the first drying, the second drying, and the third drying are each independently between 80°C and 120°C.

[0107] In some embodiments, the calcination temperature is 400℃~600℃ and the time is 3h~6h.

[0108] A specific method for preparing the titanium-silicon molecular sieve / glass microsphere composite material can be described as follows:

[0109] S100: The glass microspheres are etched using subcritical water, followed by a first water wash and a first drying.

[0110] S200: The glass microspheres obtained in step S100 are sequentially subjected to acid washing, a second water washing, and a second drying;

[0111] S300: The glass microspheres obtained in step S200 are subjected to a third water wash, a third drying, and calcination, and are set aside for later use;

[0112] S400: Dissolve a titanium source in an organic solvent to prepare an organic solution containing a titanium source;

[0113] S500: Mix template agent solution, silicon source, titanium-containing organic solution and water, age, remove organic solvent, and prepare titanium-silicon molecular sieve mother liquor;

[0114] S600: The glass microspheres obtained in step S300 and the titanium-silicon molecular sieve mother liquor prepared in step S500 are placed in a micro-reaction device with an equivalent diameter of 1.6 mm to 16 mm, and the micro-reaction device is heated and allowed to stand, so that the titanium-silicon molecular sieve mother liquor is liquidized and the titanium-silicon molecular sieve is loaded on the surface of the glass microspheres.

[0115] S700: The material obtained in step S600 is sequentially separated, washed, dried and calcined to prepare a titanium-silicon molecular sieve / glass microsphere composite material.

[0116] Secondly, this application provides a titanium-silicon molecular sieve / glass microsphere composite material, which is prepared by the preparation method described in the first aspect.

[0117] The titanium-silicon molecular sieve / glass microsphere composite material provided in this application has uniform particle size and excellent catalytic performance.

[0118] In some embodiments, the titanium-silicon molecular sieve in the titanium-silicon molecular sieve / glass microsphere composite material is a nanoparticle with an average particle size of 190 nm to 240 nm.

[0119] Thirdly, this application provides an application of the titanium-silicon molecular sieve / glass microsphere composite material as described in the second aspect as a catalyst.

[0120] The present application will be further described in detail below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this application, or follow experimental manuals or conventional conditions in the art, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0121] In the specific embodiments described below, the measurement parameters involving raw material components may have slight deviations within the weighing accuracy range unless otherwise specified. Temperature and time parameters are subject to acceptable deviations due to instrument testing accuracy or operational precision. "Room temperature" refers to 25°C.

[0122] Example 1

[0123] 1) Add 5g of glass microspheres and 195g of deionized water to a 250mL autoclave. Then seal the autoclave and gradually heat it to 300℃. Maintain the subcritical state for 5min to 10min, then turn off the heating power and cool it to room temperature. Take out the etched glass microspheres and wash them with deionized water several times until the pH reaches 7. Then place the etched glass microspheres in an 80℃ oven to dry them for later use.

[0124] 2) Take 2.5g of the etched and dried glass microspheres from step 1) into a 250mL Erlenmeyer flask and add 200mL of 0.5M hydrochloric acid solution. Then, shake in a constant temperature shaker at 200r / min and 40℃ for 5h for acid washing. Subsequently, wash the glass microspheres repeatedly with deionized water until the pH reaches 7, and then dry them in an oven at 80℃ for later use.

[0125] 3) Take 5g of the glass microspheres treated in step 2), wash them with flowing deionized water at a flow rate of 5mL / min at 80℃ for 5h to 8h, and then dry them in an oven at 80℃ for later use.

[0126] 4) Take 3g of the glass microspheres treated in step 3) and calcine them in a muffle furnace at 400℃ for 5h to obtain the glass microsphere carrier. Its scanning electron microscope image is shown below. Figure 1 As shown. By Figure 1 It can be seen that the surface of the glass microspheres changed from the original smooth and dense structure to a core-shell structure uniformly covered with fins. The presence of the fin structure significantly increased the specific surface area of ​​the glass microsphere carrier (from 0.0029 m² / g). 2 / g to 154m 2 / g), which provides a large number of nucleation sites for subsequent titanium-silicon molecular sieve loading.

[0127] 5) At room temperature, pipette 3 mL of tetrapropylammonium hydroxide solution into a 25 mL beaker, add 250 μL of deionized water, and add 2 mL of tetraethyl orthosilicate dropwise while stirring vigorously until the solution is clear and transparent. Then, slowly add 70 μL of a mixture of tetraethyl titanate and 3 mL of isopropanol. Stir at room temperature for 2–3 hours, then heat in a water bath at 80°C for 15–40 minutes to evaporate the isopropanol and ethanol, obtaining the mother liquor of the titanium silicate molecular sieve. It should be noted that during the alcohol evaporation, deionized water needs to be added intermittently to maintain the initial mass of the liquid.

[0128] 6) Take 1.0g of the calcined glass microsphere carrier from step 4) and place it in a cylindrical stainless steel microchannel with an inner diameter of 4mm, an outer diameter of 6mm, and an equivalent diameter of 4mm. Then add 1.0g of the titanium-silicon molecular sieve mother liquor prepared in step 5). After sealing the microchannel, place it in a homogeneous reactor at 130℃ for static crystallization for 5h. Subsequently, place the crystallized material in a muffle furnace at 550℃ for calcination for 6h to remove the template agent (tetrapropylammonium hydroxide), obtaining the supported titanium-silicon molecular sieve / glass microsphere composite material. The supported titanium-silicon molecular sieve / glass microsphere composite material was analyzed by scanning electron microscopy using a SU1510 microscope, yielding the following results: Figure 2 The scanning electron microscope image shown is from... Figure 2 It can be seen that the spherical granular titanium-silicon molecular sieve has been uniformly grown on the surface of the glass microsphere carrier, and the particle size is relatively uniform.

[0129] The catalytic performance of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in this embodiment was tested, and the test steps are as follows:

[0130] Solution A was prepared by mixing 0.1963 g of cyclohexanone and 0.8412 g of ammonia with 17 g of 85% tert-butanol. Solution B was prepared by mixing 0.4947 g of hydrogen peroxide with 17 g of tert-butanol. Solution A was mixed with 0.3 g of the supported titanium-silicon molecular sieve / glass microsphere composite material and preheated at 600 rpm in an 80°C water bath for 5 min. Solution B was then added, and the reaction was continued for 15 min. The reacted solution was then cooled to room temperature, centrifuged, and 1.5 mL of the supernatant was placed in a gas chromatograph. The components of the reacted solution were quantitatively analyzed using an Agilent AT ICP-8800 gas chromatograph. The test results showed that the conversion rate of cyclohexanone reached 99%, and the selectivity of the product cyclohexanone oxime reached 100%. This indicates that the supported titanium-silicon molecular sieve / glass microsphere composite material provided in this application has excellent catalytic performance.

[0131] Example 2

[0132] The preparation method of Example 2 is basically the same as that of Example 1, except that: in step 6), the mass of glass microspheres added is 0.5g, the mass of titanium-silicon molecular sieve mother liquor is 1g, and the crystallization time is 3h. Step 6) is as follows:

[0133] 0.5g of the calcined glass microsphere carrier from step 4) was placed in a cylindrical stainless steel microchannel with an inner diameter of 4mm, an outer diameter of 6mm, and an equivalent diameter of 4mm. Then, 1.0g of the titanium-silicon molecular sieve mother liquor prepared in step 5) was added. The microchannel was sealed and placed in a homogeneous reactor at 130℃ for static crystallization for 3 hours. Subsequently, the crystallized material was calcined in a muffle furnace at 550℃ for 6 hours to remove the template agent (tetrapropylammonium hydroxide), yielding a supported titanium-silicon molecular sieve / glass microsphere composite material. The supported titanium-silicon molecular sieve / glass microsphere composite material was analyzed using a SU1510 scanning electron microscope, yielding the following results: Figure 3 The scanning electron microscope image shown is from... Figure 3 It can be seen that the spherical granular titanium-silicon molecular sieve has been uniformly grown on the surface of the glass microsphere carrier, and the particle size is relatively uniform.

[0134] The catalytic performance of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in this embodiment was tested, following the same testing procedures as in Example 1. The test results showed that the conversion rate of cyclohexanone reached 99%, and the selectivity for the product cyclohexanone oxime reached 100%. This demonstrates that the supported titanium-silicon molecular sieve / glass microsphere composite material provided in this application possesses excellent catalytic performance.

[0135] Example 3

[0136] The preparation method of Example 3 is basically the same as that of Example 1, except that: the mass of glass microspheres added in step 6) is 0.2g, the mass of titanium-silicon molecular sieve mother liquor is 1g, and the crystallization time is 1h. Step 6) is as follows:

[0137] 0.2g of the calcined glass microsphere carrier from step 4) was placed in a cylindrical stainless steel microchannel with an inner diameter of 4mm, an outer diameter of 6mm, and an equivalent diameter of 4mm. Then, 1.0g of the titanium-silicon molecular sieve mother liquor prepared in step 5) was added. The microchannel was sealed and placed in a homogeneous reactor at 130℃ for static crystallization for 1 hour. Subsequently, the crystallized material was calcined in a muffle furnace at 550℃ for 6 hours to remove the template agent (tetrapropylammonium hydroxide), yielding a supported titanium-silicon molecular sieve / glass microsphere composite material. The supported titanium-silicon molecular sieve / glass microsphere composite material was analyzed using a SU1510 scanning electron microscope, yielding the following results: Figure 4 The scanning electron microscope image shown is from... Figure 4 It can be seen that the spherical granular titanium-silicon molecular sieve has been uniformly grown on the surface of the glass microsphere carrier, and the particle size is relatively uniform.

[0138] The catalytic performance of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in this embodiment was tested, following the same testing procedures as in Example 1. The test results showed that the conversion rate of cyclohexanone reached 99%, and the selectivity for the product cyclohexanone oxime reached 100%. This demonstrates that the supported titanium-silicon molecular sieve / glass microsphere composite material provided in this application possesses excellent catalytic performance.

[0139] Example 4

[0140] The preparation method of Example 4 is basically the same as that of Example 1, except that the inner diameter of the cylindrical stainless steel microchannel in step 6) is 6 mm and the crystallization time is 1 hour. Step 6) is as follows:

[0141] 0.2g of the calcined glass microsphere carrier from step 4) was placed in a cylindrical stainless steel microchannel with an inner diameter of 6mm, an outer diameter of 8mm, and an equivalent diameter of 6mm. Then, 1.0g of the titanium-silicon molecular sieve mother liquor prepared in step 5) was added. The microchannel was sealed and placed in a homogeneous reactor at 130℃ for static crystallization for 1 hour. Subsequently, the crystallized material was calcined in a muffle furnace at 550℃ for 6 hours to remove the template agent (tetrapropylammonium hydroxide), yielding a supported titanium-silicon molecular sieve / glass microsphere composite material. The supported titanium-silicon molecular sieve / glass microsphere composite material was analyzed using a SU1510 scanning electron microscope, yielding the following results: Figure 5 The scanning electron microscope image shown is from... Figure 5 It can be seen that the spherical granular titanium-silicon molecular sieve has been uniformly grown on the surface of the glass microsphere carrier, and the particle size is relatively uniform.

[0142] The catalytic performance of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in this embodiment was tested, following the same testing procedures as in Example 1. The test results showed that the conversion rate of cyclohexanone reached 99%, and the selectivity for the product cyclohexanone oxime reached 100%. This demonstrates that the supported titanium-silicon molecular sieve / glass microsphere composite material provided in this application possesses excellent catalytic performance.

[0143] Example 5

[0144] The preparation method of Example 5 is basically the same as that of Example 1, except that the inner diameter of the cylindrical stainless steel microchannel in step 6) is 8 mm and the crystallization time is 1 hour. Step 6) is as follows:

[0145] 0.2g of the calcined glass microsphere carrier from step 4) was placed in a cylindrical stainless steel microchannel with an inner diameter of 8mm, an outer diameter of 10mm, and an equivalent diameter of 8mm. Then, 1.0g of the titanium-silicon molecular sieve mother liquor prepared in step 5) was added. The microchannel was sealed and placed in a homogeneous reactor at 130℃ for static crystallization for 1 hour. Subsequently, the crystallized material was calcined in a muffle furnace at 550℃ for 6 hours to remove the template agent (tetrapropylammonium hydroxide), yielding a supported titanium-silicon molecular sieve / glass microsphere composite material. The supported titanium-silicon molecular sieve / glass microsphere composite material was analyzed using a SU1510 scanning electron microscope, yielding the following results: Figure 6 The scanning electron microscope image shown is from... Figure 6 It can be seen that the spherical granular titanium-silicon molecular sieve has been uniformly grown on the surface of the glass microsphere carrier, and the particle size is relatively uniform.

[0146] The catalytic performance of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in this embodiment was tested, following the same testing procedures as in Example 1. The test results showed that the conversion rate of cyclohexanone reached 99%, and the selectivity for the product cyclohexanone oxime reached 100%. This demonstrates that the supported titanium-silicon molecular sieve / glass microsphere composite material provided in this application possesses excellent catalytic performance.

[0147] Example 6

[0148] The preparation method of Example 6 is basically the same as that of Example 1, except that a cubic stainless steel microchannel is used instead of the cylindrical stainless steel microchannel in step 6). Step 6) is as follows:

[0149] 0.5g of the calcined glass microsphere carrier from step 4) was placed in a cubic stainless steel microchannel with an equivalent diameter of 4mm. Then, 1.0g of the titanium-silicon molecular sieve mother liquor prepared in step 5) was added. The microchannel was sealed and placed in a homogeneous reactor at 130℃ for static crystallization for 3 hours. Subsequently, the crystallized material was calcined in a muffle furnace at 550℃ for 6 hours to remove the template agent (tetrapropylammonium hydroxide), yielding a supported titanium-silicon molecular sieve / glass microsphere composite material. The supported titanium-silicon molecular sieve / glass microsphere composite material was analyzed using a SU1510 scanning electron microscope, yielding the following results: Figure 7 The scanning electron microscope image shown is from... Figure 7 It can be seen that the spherical granular titanium-silicon molecular sieve has been uniformly grown on the surface of the glass microsphere carrier, and the particle size is relatively uniform.

[0150] The catalytic performance of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in this embodiment was tested, following the same testing procedures as in Example 1. The test results showed that the conversion rate of cyclohexanone reached 99%, and the selectivity for the product cyclohexanone oxime reached 100%. This demonstrates that the supported titanium-silicon molecular sieve / glass microsphere composite material provided in this application possesses excellent catalytic performance.

[0151] Comparative Example 1

[0152] The preparation method of Comparative Example 1 uses a traditional stainless steel hydrothermal crystallization kettle as the reactor. That is, a stainless steel hydrothermal crystallization kettle is used instead of the cylindrical stainless steel microchannel in Example 1. Step 6) is as follows:

[0153] 1.0 g of the calcined glass microsphere carrier from step 4) was placed in a stainless steel hydrothermal crystallization kettle, and then 10.0 g of the titanium-silicon molecular sieve mother liquor prepared in step 5) was added. The hydrothermal crystallization kettle was placed in a homogeneous reactor at 170℃ and allowed to crystallize for 72 h. Subsequently, the crystallized material was placed in a muffle furnace at 550℃ and calcined for 6 h to remove the template agent (tetrapropylammonium hydroxide), yielding a supported titanium-silicon molecular sieve / glass microsphere composite material. The supported titanium-silicon molecular sieve / glass microsphere composite material was analyzed using a SU1510 scanning electron microscope, yielding the following results: Figure 8 The scanning electron microscope image shown is from... Figure 8 It is known that spherical granular titanium silicate molecular sieves are difficult to grow uniformly on the surface of glass microsphere carriers, with large particle size (average particle size 350nm) and uneven particle size.

[0154] The catalytic performance of the supported titanium-silicon molecular sieve / glass microsphere composite material prepared in this comparative example was tested, following the same testing procedures as in Example 1. The test results showed that the conversion rate of cyclohexanone reached 91.7%, and the selectivity of the product cyclohexanone oxime reached 99%. This indicates that the catalytic performance of the supported titanium-silicon molecular sieve / glass microsphere composite material provided in Comparative Example 1 is relatively poor.

[0155] As can be seen from the test results of the examples and comparative examples, the preparation method provided in this application can make the size and distribution of the supported titanium-silicon molecular sieve / glass microsphere composite material uniform in different batches, that is, the synthesis stability between different batches is high and the catalytic performance is good. In contrast, the supported titanium-silicon molecular sieve / glass microsphere composite material prepared by the traditional method has uneven distribution and size, resulting in a significant reduction in its catalytic performance.

[0156] Furthermore, the test results of Examples 1 and 6 show that uniform loading and uniform particle size of the supported titanium-silicon molecular sieve / glass microsphere composite material can be achieved by adjusting the size of the reaction vessel within the scope of this application, and the shape of the reaction vessel is not significantly related.

[0157] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0158] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification and drawings can be used to interpret the scope of the claims.

Claims

1. A method for preparing a titanium-silicon molecular sieve / glass microsphere composite material, characterized in that, Includes the following steps: The titanium-silicon molecular sieve mother liquor and glass microspheres are placed in a micro-reaction device with an equivalent diameter of 1.6 mm to 16 mm. The micro-reaction device is heated to liquidate the titanium-silicon molecular sieve mother liquor and load the titanium-silicon molecular sieve onto the surface of the glass microspheres to prepare the titanium-silicon molecular sieve / glass microsphere composite material. Before placing the glass microspheres into the microreactor, the process further includes etching, acid washing, water washing, drying, and calcining the glass microspheres with subcritical water; the acid washing step includes immersing the glass microspheres in an inorganic acid with a concentration of 0.5M to 1.0M for 5 hours to 8 hours. The micro-reaction device is a closed tubular channel; The mass ratio of the glass microspheres to the mother liquor of the titanium-silicon molecular sieve is 1:(1~5). The glass microspheres have a particle size of 70μm~150μm; The heating temperature for heating the micro-reaction device is 100℃~170℃, and the heating time is 0.1h~24h.

2. The preparation method according to claim 1, characterized in that, The microreactor is made of metal.

3. The preparation method according to claim 1, characterized in that, The mother liquor of the titanium-silicon molecular sieve includes a titanium source, a silicon source, a template agent, and water.

4. The preparation method according to claim 3, characterized in that, The molar ratio of the titanium source to the silicon source is 1:(0.01~1).

5. The preparation method according to claim 3, characterized in that, The molar ratio of the template agent to the silicon source is 1:(0.1~0.7).

6. The preparation method according to claim 3, characterized in that, The molar ratio of the silicon source to the water is 1:(50~100).

7. The preparation method according to claim 3, characterized in that, It meets at least one of the following characteristics: 1) The titanium source includes one or more of tetraethyl titanate, tetrabutyl titanate, and titanium tetrachloride; 2) The silicon source includes tetraethyl orthosilicate and / or silica sol; 3) The template agent includes one or more of tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and piperidine quaternary ammonium hydroxide.

8. The preparation method according to claim 3, characterized in that, The mother liquor of the titanium-silicon molecular sieve is prepared by a method including the following steps: The titanium source is dissolved in an organic solvent to prepare an organic solution containing the titanium source; The template agent, the silicon source, the titanium-containing organic solution, and water are mixed, aged, and the organic solvent is removed to prepare the titanium-silicon molecular sieve mother liquor.

9. The preparation method according to claim 8, characterized in that, It meets at least one of the following characteristics: 1) The organic solvents include alcohol solvents and / or alkane solvents; 2) The aging temperature is 20℃~80℃, and the time is 3h~24h; 3) The molar ratio of the organic solvent to the titanium source is 1:(0.001~0.003). 4) The method for removing the organic solvent is heating, wherein the heating temperature is 60℃~95℃ and the heating time is 10min~45min.

10. The preparation method according to claim 3, characterized in that, After heating the microreactor, the method further includes a step of calcining the heated material to remove the template agent.

11. The preparation method according to claim 10, characterized in that, The roasting temperature is 550℃~600℃, and the time is 5h~8h.

12. The preparation method according to any one of claims 1 to 11, characterized in that, The water flow rate for the washing process is 3 mL / min to 5 mL / min, and the time is 5 h to 8 h.

13. The preparation method according to any one of claims 1 to 11, characterized in that, The drying temperature is 80℃~120℃.

14. The preparation method according to any one of claims 1 to 11, characterized in that, The roasting temperature is 400℃~600℃, and the time is 3h~6h.

15. A titanium-silicon molecular sieve / glass microsphere composite material, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 14.

16. The titanium-silicon molecular sieve / glass microsphere composite material as described in claim 15, characterized in that, The titanium-silicon molecular sieve in the titanium-silicon molecular sieve / glass microsphere composite material is a nanoparticle with an average particle size of 190nm~240nm.

17. The application of the titanium-silicon molecular sieve / glass microsphere composite material as described in claim 15 or 16 as a catalyst.

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