Titanium silicalite molecular sieve/glass bead composite material as well as preparation method and application thereof

Titanium-silicon molecular sieve/glass microsphere composite materials, their preparation methods and application technologies

[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 application.

Background Technology

[0002] Titanium silicate molecular sieve, abbreviated as TS-1, is a type of ZSM-5 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. The sinusoidal channel diameter along the (100) direction is 0.51 nm x 0.55 nm, and the straight channel diameter along the (010) direction is 0.53 nm x 0.56 nm. Due to the special channel structure and the introduction of titanium atoms, the oxidation system composed of 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 reaction of alkanes, the epoxidation reaction of alkenes, the oxidation reaction 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, the traditional method of directly reacting titanium-silicon molecular sieve nanoparticles with silicon and titanium sources in a stainless steel crystallization reactor has the following problems: First, due to the high surface energy of titanium-silicon molecular sieve nanoparticles, they are prone to agglomeration into micron-sized particles during actual 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, resulting in reduced catalytic activity. Second, the separation and recovery of titanium-silicon molecular sieve nanoparticles after the reaction is difficult. Currently, membrane filtration is mainly used to separate the nanoparticles from the reaction system. However, after a few uses, the membrane pores are easily blocked, rendering the entire separation membrane unusable. The replacement cost of the membrane accounts for a significant proportion of the overall process cost. In addition, using a crystallization reactor for the reaction also results in a long growth cycle (6-30 days) for titanium-silicon molecular sieve nanoparticles, uneven particle size, and high cost.

Summary of the Invention

[0004] Based on this, 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 mother liquor of titanium silicon molecular sieve 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 mother liquor of titanium silicon molecular sieve 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.

[0007] In some embodiments, the micro-reaction device is a closed tubular channel;

[0008] and/or, the material of the micro-reaction device is metal.

[0009] In some embodiments, the mass ratio of the glass microspheres to the titanium-silicon molecular sieve mother liquor 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:(0.1~0.7);

[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 features:

[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 features:

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

[0024] 2) The aging temperature is 20°C~80°C, 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°C to 95°C, and the heating time is...

10min ~45min.

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

[0028] Optionally, the calcination temperature is 550°C to 600°C and the time is 5h to 8h.

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

[0030] In some embodiments, before placing the glass microspheres in the micro-reaction device, the steps of etching, acid washing, water washing, drying and calcining the glass microspheres with subcritical water are further included.

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

[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°C to 120°C;

[0034] Optionally, the calcination temperature is 400 °C to 600 °C and the time is 3h to 6h.

[0035] In a second aspect, 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 nanoparticles, the titanium-silicon molecular sieve in the titanium-silicon molecular sieve/glass microsphere composite material is nanoparticles, and the average particle size of the nanoparticles is 190nm~240nm.

[0037] In a third aspect, 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 preparation method of the titanium-silicon molecular sieve/glass microsphere composite material provided in this application uses a micro-reaction device (equivalent diameter W16mm). Compared with the traditional hydrothermal crystallization kettle, the micro-reaction device with a specific equivalent diameter has superior heat transfer performance, significantly improving the heating rate, thereby shortening the induction period, accelerating the nucleation process of the titanium-silicon molecular sieve, thus shortening the growth cycle of the composite material (at least as low as 0.1h), and reducing the particle size of the titanium-silicon molecular sieve.

This can shorten the internal diffusion mass transfer path between reactants and products, improve mass transfer efficiency, and increase the reaction rate. In addition, the use of a microreactor can promote heterogeneous nucleation of the mother liquor of titanium-silicon molecular sieves, avoiding homogeneous nucleation. This ensures that the titanium-silicon molecular sieves are uniformly loaded on the surface of glass microspheres, avoiding the problem of easy agglomeration. Consequently, it significantly improves the utilization rate of raw materials, enhances catalytic performance, and greatly reduces the generation of wastewater and waste.

[0039] In addition, the micro-reaction device is small, which can ensure that there is a very narrow temperature and concentration gradient inside, making the overall crystallization conditions more uniform. This allows the growth process of titanium silicon molecular sieves to have strong consistency, ensuring the particle size uniformity of composite materials obtained in different batches, thus having excellent catalytic performance.

[0040] In summary, the preparation method provided by 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 is a scanning electron microscope (SEM) image of the glass microsphere carrier after etching treatment in Example 1;

[0042] Figure 2 is a scanning electron microscope (SEM) image of the supported titanium-silicon molecular sieve/glass microsphere composite material prepared in Example 1; [0043] Figure 3 is a scanning electron microscope (SEM) image of the supported titanium-silicon molecular sieve/glass microsphere composite material prepared in Example 2; [0044] Figure 4 is a scanning electron microscope (SEM) image of the supported titanium-silicon molecular sieve/glass microsphere composite material prepared in Example 3; [0045] Figure 5 is a scanning electron microscope (SEM) image of the supported titanium-silicon molecular sieve/glass microsphere composite material prepared in Example 4; [0046] Figure 6 is a scanning electron microscope (SEM) image of the supported titanium-silicon molecular sieve/glass microsphere composite material prepared in Example 5; [0047] Figure 7 is a scanning electron microscope (SEM) image of the supported titanium-silicon molecular sieve/glass microsphere composite material prepared in Example 6; [0048] Figure 8 is 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 of the application will be given below with reference to the accompanying drawings. Preferred embodiments of the application are shown in the drawings. However, the application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that a thorough and complete understanding of the disclosure of this application will be achieved.

[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 this application.

[0051] Terminology:

[0052] The term "and/or as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including 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 more,""particularly,""for example,""e.g.,""example, and "example are used for descriptive purposes to indicate that different technical solutions preceding and following each other are related in terms of their coverage, but should not be construed as limiting the preceding technical solution or restricting the scope of protection of this document. In this document, unless otherwise specified, A (e.g., B) represents...

B is a non-restrictive 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 refers to 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," "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," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0057] In this document, 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 a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of selectable numerical values within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within the numerical 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 the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The "numerical interval can be broadly included to include numerical interval types such as percentage intervals, ratio intervals, and proportion intervals.

[0059] In this document, the term "room temperature or "normal temperature generally refers 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, where the method flow involves multiple steps, unless otherwise explicitly stated herein, there is no strict order restriction on the execution of these steps, and they may be executed in an order other than that 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 the above-mentioned drawbacks 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 to prepare the titanium-silicon molecular sieve/glass microsphere composite material.

[0064] The preparation method of the titanium-silicon molecular sieve/glass microsphere composite material provided in this application employs a micro-reaction device (equivalent diameter W 16 mm). Compared with the traditional hydrothermal crystallization kettle, the micro-reaction device with a specific equivalent diameter has more advantages.

The excellent heat transfer performance significantly improves the heating rate, thereby shortening the induction period and accelerating the nucleation process of titanium-silicon molecular sieves. This shortens the growth cycle of the composite material (by at least 0.1 hours), reduces the particle size of the titanium-silicon molecular sieves, and shortens the internal diffusion mass transfer path of reactants and products, improving mass transfer efficiency and reaction rate. Furthermore, the use of a microreactor promotes heterogeneous nucleation of the titanium-silicon molecular sieve mother liquor, preventing homogeneous nucleation. This ensures that the titanium-silicon molecular sieves are uniformly loaded on the surface of the glass microspheres, avoiding agglomeration. This significantly improves raw material utilization, enhances catalytic performance, and substantially reduces wastewater and waste generation.

[0065] In addition, the micro-reaction device is small, which can ensure that there is a very narrow temperature and concentration gradient inside, making the overall crystallization conditions more uniform. This allows the growth process of titanium silicon molecular sieves to have strong consistency, ensuring the particle size uniformity of composite materials obtained in different batches, thus having excellent catalytic performance.

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

[0067] To avoid the problems of easy agglomeration of traditionally prepared titanium-silicon molecular sieves and easy pore blockage during separation, some researchers have proposed to granulate or prepare titanium-silicon molecular sieves using a loading method, for example, using cordierite or carbon nanofibers as supports. However, the granulation method will prevent the internal particles of the titanium-silicon molecular sieve from participating in the catalytic process, resulting in low utilization. The above-mentioned support has poor bonding force with the titanium-silicon molecular sieve, which easily leads to its detachment. Moreover, the specific surface area of the currently used support is small, which makes it difficult to provide enough heterogeneous nucleation sites for the titanium-silicon molecular sieve mother liquor, resulting in low loading. At the same time, it will cause significant homogeneous nucleation of the titanium-silicon molecular sieve mother liquor, resulting in waste of mother liquor and the generation of a large amount of polluting wastewater. This application uses glass microspheres as a support, and the titanium-silicon molecular sieve can exist only on the surface of the glass microspheres, thereby completely solving the problem that the internal titanium-silicon molecular sieve cannot participate in catalysis.

[0068] In this application, crystallization is specifically heated and statically crystallized, that is, the micro-reaction device is kept in a static state during the heating process.

[0069] It is understood that the equivalent diameter can be used to compare the size and shape similarity of different shapes. When the equivalent diameters are similar, it indicates that their sizes (volume, area) are similar. In this application, the 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 micro-reaction device 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 can give it the largest specific surface area, further improving the heat transfer performance of the micro-reaction device and increasing its heating rate.

[0071] In order to improve heat transfer performance, the material of the micro-reactor in this application is metal, such as stainless steel. More 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 glass microspheres of various sizes can be selected. In some embodiments, the particle size of the glass microspheres is 70 μm to 150 μm, for example, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm.

[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, 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 the glass microspheres in the form of spherical crystals.

noodle.

[0076] In some embodiments, the mother liquor of the titanium-silicon molecular sieve 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] Further, 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; 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 calculation standard for the molar ratio of silicon source to water is the sum of water in the template agent and water added during the removal of organic solvent.

[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] The 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] Further, 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 selection of organic solvents is not limited, as long as they can dissolve the titanium source and have volatile properties. In some embodiments, the organic solvents include 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] Further, 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 the process parameters commonly used in the preparation of titanium-silicon molecular sieve mother liquor can be selected. In some embodiments, the aging temperature is 20°C to 80°C and the time is 3h to 24h; preferably, the aging temperature is 40°C to 60°C and the time is 5h to 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. In order to avoid the change in its quality, water can be added intermittently during the removal of organic solvents.

[0089] In this application, the method or apparatus used to heat the micro-reaction device is not limited. As an example, the micro-reaction device is placed in a homogeneous reactor for heating.

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

[0091] In some embodiments, after heating the microreactor, the method further includes processing the material obtained after heating.

The steps include separation, washing, and drying.

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

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

[0094] Optionally, the calcination temperature is 550 °C to 600 °C and the time is 5 h to 8 h.

[0095] In some embodiments, before placing the glass microspheres into the microreactor, a step of etching the glass microspheres with 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 can be understood that subcritical water refers to liquid water with a temperature of 250°C to 310°C.

[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 method 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 with water a second time and dried a second time;

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

[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 5h to 8h; 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] It is understood that the second water wash is to remove excess inorganic acid, so as to wash 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 80°C to 120°C.

[0107] In some embodiments, the calcination temperature is 400°C to 600°C and the time is 3h to 6h.

[0108] According to a specific embodiment, the preparation method of the titanium-silicon molecular sieve/glass microsphere composite material can be 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 acid-washed, washed with water a second time, and dried a second time;

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

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

The mother liquid crystallizes and loads titanium-silicon molecular sieves onto the surface of 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] In a second aspect, 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 a 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, and the average particle size of the nanoparticle is 190nm~240nm.

[0119] In a third aspect, this application provides the 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 only used to illustrate the present application 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 instructions given in the present application first, or follow the experimental manual 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, unless otherwise specified, slight deviations may exist within the weighing accuracy range for the measurement parameters of the raw material components. For temperature and time parameters, acceptable deviations due to instrument testing accuracy or operational accuracy are allowed. "Room temperature" refers to 25°C.

[0122] Example 1

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

[0124] 2) Take 2.5g of the etched and dried glass microspheres from step 1) into a 250mL conical flask, and add 200mL of a concentration of

A 0.5M hydrochloric acid solution was prepared. The glass microspheres were then shaken for 5 hours in a constant-temperature shaker at 200 rpm and 40°C for acid washing. They were then washed repeatedly with deionized water until the pH reached 7, and finally dried in an oven at 80°C 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°C for 5h~8h, and then dry them in an oven at 80°C for later use.

[0126] 4) Take 3g of the glass microspheres treated in step 3) and calcine them in a muffle furnace at 400 °C for 5h to obtain a glass microsphere carrier. Its scanning electron microscope image is shown in Figure 1. As can be seen from Figure 1, 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 0.0029m²).²/ g to 154m²(/g), which provides a large number of nucleation sites for subsequent titanium-silicon molecular sieve loading.

[0127] 5) At room temperature, use a pipette to take 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 mixed solution of tetraethyl titanate and 3 mL of isopropanol. After stirring at room temperature for 2-3 hours, heat and stir in a water bath at 80°C for 15-40 minutes to evaporate the isopropanol and ethanol, thus obtaining the mother liquor of 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) and seal the microchannel.

After sealing, the material was placed in a homogeneous reactor at 130°C for static crystallization for 5 hours. Subsequently, the crystallized material was calcined in a muffle furnace at 550°C 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, and the resulting scanning electron microscope image is shown in Figure 2. Figure 2 shows that the spherical titanium-silicon molecular sieve particles have grown uniformly 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. 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 and 0.3 g of the supported titanium-silicon molecular sieve/glass microsphere composite material were mixed and preheated at 600 rpm in a water bath at 80 °C for 5 min. Solution B was then added, and the reaction was continued for 15 min. The reaction 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 reaction 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: the mass of glass microspheres added in step 6) 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] Take 0.5g 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°C for static crystallization for 3h. Subsequently, place the crystallized material in a muffle furnace at 550°C for calcination for 6h to remove the template agent (tetrapropylammonium hydroxide), and obtain 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 an SU1510 EM microscope, and the scanning electron microscopy image shown in Figure 3 was obtained. As can be seen from Figure 3, 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, and the test steps were the same as in Example 1. 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.

[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] Take 0.2g 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°C for static crystallization for 1h. Subsequently, place the crystallized material in a muffle furnace at 550°C for calcination for 6h to remove the template agent (tetrapropylammonium hydroxide), and obtain 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 EM microscope, and the scanning electron microscopy image shown in Figure 4 was obtained. As can be seen from Figure 4, the spherical granular titanium-silicon molecular sieve has been uniformly grown onto the glass microspheres.

The carrier surface has relatively uniform particle size.

[0138] The catalytic performance of the supported titanium-silicon molecular sieve/glass microsphere composite material prepared in this embodiment was tested, and the test steps were the same as in Example 1. 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.

[0139] Example 4

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

[0141] Take 0.2g of the calcined glass microsphere carrier from step 4) and place it in a cylindrical stainless steel microchannel with an inner diameter of 6mm, an outer diameter of 8mm, and an equivalent diameter of 6mm. 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°C for static crystallization for 1h. Subsequently, place the crystallized material in a muffle furnace at 550°C for calcination for 6h to remove the template agent (tetrapropylammonium hydroxide), and obtain 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 an SU1510 EM microscope, and the scanning electron microscopy image shown in Figure 5 was obtained. As can be seen from Figure 5, 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, and the test steps were the same as in Example 1. 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.

[0143] Example 5

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

[0145] Take 0.2g of the calcined glass microsphere carrier from step 4) and place it in a cylindrical stainless steel microchannel with an inner diameter of 8mm, an outer diameter of 10mm, and an equivalent diameter of 8mm. 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°C for static crystallization for 1h. Subsequently, place the crystallized material in a muffle furnace at 550°C for calcination for 6h to remove the template agent (tetrapropylammonium hydroxide), and obtain 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 an SU1510 EM microscope, and the scanning electron microscopy image shown in Figure 6 was obtained. As can be seen from Figure 6, 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, and the test steps were the same as in Example 1. 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.

[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] Take 0.5g of the calcined glass microsphere carrier from step 4) and place it in a cubic stainless steel microchannel with 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 environment at 130°C.

The material was allowed to crystallize statically in the reactor for 3 hours. Subsequently, the crystallized material was calcined in a muffle furnace at 550°C 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, and the resulting SEM image is shown in Figure 7. Figure 7 shows that the spherical titanium-silicon molecular sieve particles have grown uniformly 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, and the test steps were the same as in Example 1. 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.

[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 to replace the cylindrical stainless steel microchannel in Example 1. Step 6) is as follows:

[0153] Take 1.0g of the calcined glass microsphere carrier from step 4) and place it in a stainless steel hydrothermal crystallization kettle. Then add 10.0g of the titanium-silicon molecular sieve mother liquor prepared in step 5). Place the hydrothermal crystallization kettle in a homogeneous reactor at 170°C and let it stand for crystallization for 72h. Then, place the crystallized material in a muffle furnace at 550°C and calcine for 6h to remove the template agent (tetrapropylammonium hydroxide) to obtain 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 EM microscope, and the scanning electron microscopy image shown in Figure 8 was obtained. As can be seen from Figure 8, the spherical granular titanium-silicon molecular sieve is difficult to grow uniformly on the surface of the glass microsphere carrier. The particle size is large (average particle size 350nm) and the particle size is not uniform.

[0154] The catalytic performance of the supported titanium-silicon molecular sieve/glass microsphere composite material prepared in this comparative example was tested, and the test steps were the same 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 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. However, the distribution and size of the supported titanium-silicon molecular sieve/glass microsphere composite material prepared by the traditional method are not uniform, resulting in a significant reduction in its catalytic performance.

[0156] Furthermore, the test results of Examples 1 and 6 show that the 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. In order to make the description concise, 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 record.

[0158] The embodiments described above are merely examples of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that, for those skilled in the art, several modifications and improvements can be made 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 scope of the drawings can be used to interpret the claims.

CN 117138835 B