Delaminated MCM-22 molecular sieve and preparation method thereof

Abstract

The invention provides a delaminated MCM-22 molecular sieve and a preparation method thereof. According to the method, the MCM-22 molecular sieve is delaminated by adopting a specific amine source, so that the delaminating efficiency is remarkably improved, the specific surface area of the MCM-22 molecular sieve is increased, the operation difficulty is reduced, and meanwhile, the activity of the molecular sieve is effectively maintained. By selecting different amine sources, the layered structure of the molecular sieve can be efficiently stripped, and ideal secondary pore characteristics are obtained. The method is simple and convenient to operate and excellent in stripping effect, has a good environment-friendly characteristic, and meets the requirements of modern industry for sustainable development.

Description

Technical Field

[0001] The invention relates to the technical field of molecular sieve materials, and more particularly to a stripped MCM-22 molecular sieve and a preparation method thereof. Background Art

[0002] MCM-22 molecular sieve is an acidic catalyst with a layered structure and belongs to the zeolite molecular sieve. Due to its unique pore structure and good acidic properties, MCM-22 has shown excellent catalytic performance in the fields of catalytic cracking, isomerization and fine chemical synthesis. Especially in the petrochemical industry, MCM-22 is widely used in the preparation of modified catalysts, such as playing an important role in light hydrocarbon conversion and selective conversion of aromatics. However, with the diversification and efficiency of catalyst requirements, the performance of traditional MCM-22 in catalytic reactions sometimes fails to meet the needs of modern industry. In particular, its relatively small pore diameter limits the entry of macromolecular reactants and reduces the catalytic efficiency.

[0003] In order to overcome this problem, scientists began to explore the stripping technology of MCM-22. Through stripping, the specific surface area and pore volume of the molecular sieve can be effectively increased, which can promote the contact of a large number of reactants and thus improve the efficiency of the catalytic reaction. Traditional stripping methods mainly include chemical stripping and physical stripping. Chemical stripping often uses strong acid or alkaline chemical reagents. Although these methods are effective, they may cause the destruction of the active center of the molecular sieve and the reduction of catalytic performance; while physical stripping usually requires conditions such as high temperature and high pressure, which is complicated to operate and has high cost.

[0004] In recent years, researchers have begun to focus on the use of amine compounds as stripping agents. Amine compounds have strong affinity and can promote the stripping of molecular sieve layers by reacting with the acidic sites of molecular sieves. However, existing amine source stripping methods often have problems such as low efficiency and poor selectivity, resulting in unsatisfactory stripping effects and difficulty in industrial application.

[0005] In view of these problems, the present invention proposes a novel stripping method for MCM-22 molecular sieve based on a specific amine source. The method can effectively improve the stripping efficiency, reduce the difficulty of operation, and maintain the activity of the molecular sieve at the same time. It has the advantages of simple operation, good stripping effect, and environmental protection, and has expanded a new direction for the application of MCM-22 molecular sieve. Therefore, the development and research of this novel stripping method has important theoretical significance and broad application prospects. Summary of the invention

[0006] In view of this, the present invention provides a stripped MCM-22 molecular sieve and a preparation method thereof.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A stripped MCM-22 molecular sieve, comprising the following components: MCM-22 molecular sieve raw powder, hexadecyltrimethylammonium bromide, an amine source and water;

[0009] The mass ratio of the MCM-22 molecular sieve raw powder, hexadecyltrimethylammonium bromide, amine source and water is (0.2-1.2):(1.0-3.8):(1.4-4.0):(50-90).

[0010] Preferably, the amine source is one of tetrapropylammonium hydroxide, cyclohexylamine, triethylamine, ethanolamine, triethanolamine, and 2,6-dimethylaniline.

[0011] To select a suitable amine source for the stripping reaction of MCM-22 molecular sieve, first of all, the amine source should have a moderate molecular weight, so as to ensure that it has good permeability in the reaction with MCM-22 molecular sieve, and will not limit the effective reaction due to being too large, nor will it cause uncontrollable side reactions due to being too small.

[0012] Another object of the present invention is to provide a method for preparing the above-mentioned stripped MCM-22 molecular sieve, comprising the following steps:

[0013] First, the MCM-22 molecular sieve is pretreated to remove impurities and obtain pure MCM-22 molecular sieve. During the pretreatment process, the MCM-22 molecular sieve is first rinsed with deionized water to remove inorganic salts, metal ions and other impurities remaining on the surface. In order to ensure the effective removal of impurities, ultrasonic cleaning or mechanical stirring can be used, which helps to improve the separation efficiency between impurities and molecular sieves. After washing, the MCM-22 molecular sieve is placed in a high-temperature furnace for heat treatment, and the temperature is usually set at 400-550°C for several hours. This heat treatment process can not only remove moisture and possible organic impurities, but also enhance the stability and catalytic activity of the molecular sieve. After the above steps, a pure MCM-22 molecular sieve is finally obtained, ready for the subsequent stripping reaction.

[0014] Next, select a suitable amine source for the stripping reaction of the MCM-22 molecular sieve, and select compounds containing amino groups or quaternary ammonium salts, such as cyclohexylamine, triethylamine, ethanolamine, triethanolamine, 2,6-dimethylaniline, etc. Among these compounds, when selecting a specific amine source, its characteristics need to be considered. First of all, the amine source should have a moderate molecular weight, so that it can ensure good permeability in the reaction with the MCM-22 molecular sieve, and will not limit the effective reaction due to being too large, nor will it cause uncontrollable side reactions due to being too small. In addition, moderate alkalinity is also an important characteristic of this amine source, which can effectively react with the acidic sites in the MCM-22 molecular sieve to promote the stripping process. If the alkalinity is too strong, it may lead to excessive neutralization of the acidic sites of the molecular sieve, thereby reducing the catalytic activity, and if the alkalinity is insufficient, it may cause insufficient reaction.

[0015] At the same time, the selected amine source must have good solubility. This property ensures that the amine source can be evenly distributed in the reaction system during the reaction, thereby improving the efficiency of the reaction and promoting effective interaction and mass transfer between reactants. Finally, considering environmental protection and personnel safety, the selected amine source should be an environmentally friendly and non-toxic compound, which can not only reduce the impact of the operation process on personnel health, but also reduce pollution to the environment, which is in line with the sustainable development concept of modern chemical industry.

[0016] By comprehensively considering these factors, when selecting the amine source, compounds that meet the above conditions can be selected in a targeted manner to ensure the efficiency and safety of the subsequent stripping reaction. The MCM-22 molecular sieve is placed in a reactor, and an appropriate amount of amine source is first added. The selection of the amine source should be based on the interaction force and reaction activity between it and the MCM-22 molecular sieve to ensure the effectiveness of the stripping reaction. Next, deionized water is added to adjust the pH of the reaction system. The amount of deionized water should be adjusted as needed to ensure the stability of the reaction environment and optimize the stripping effect.

[0017] During the reaction, the reactor is heated to a specific temperature range (e.g., 80-120°C). This temperature range helps to increase the reaction rate between the amine source and the MCM-22 molecular sieve and promote the stripping reaction. The reaction is maintained for a certain time (e.g., 4-12 hours), during which the amine source will exchange with the connection sites of the MCM-22 molecular sieve, gradually stripping the layered structure of the molecular sieve. The choice of reaction time should be optimized according to the specific experimental conditions and the target stripping effect to achieve the best stripping effect.

[0018] After the reaction is completed, the reactor is taken out and properly cooled and washed to remove the unreacted amine source and other by-products. Finally, the stripped MCM-22 molecular sieve sample is obtained by drying.

[0019] After the reaction is completed, the reaction mixture needs to be cooled to room temperature to ensure the safety and effectiveness of the subsequent treatment process. After cooling, the reaction mixture is washed with deionized water to remove unreacted amine source and possible by-products. This step can be washed multiple times to ensure the thorough removal of impurities, so as to obtain a purer MCM-22 molecular sieve after stripping.

[0020] Subsequently, the MCM-22 molecular sieve after exfoliation is collected by centrifugation or filtration. Centrifugation can effectively separate solids and liquids and quickly obtain molecular sieves, while filtration physically leaves solids on the filter membrane to obtain clear washing liquid. Both methods have their own advantages and disadvantages, and the appropriate method can be selected according to specific experimental conditions. The collected MCM-22 molecular sieve needs to be dried at a suitable temperature, usually in a vacuum drying oven, to ensure the stability of its structure and remove all residual moisture.

[0021] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following beneficial effects: peeling can increase the specific surface area and pore volume of the molecular sieve, thereby improving its catalytic performance and adsorption performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0023] Figure 1 This is an XRD comparison diagram of ITQ-2 molecular sieve in the embodiment of the present invention.

[0024] Figure 2 This is a BET comparison diagram of ITQ-2 molecular sieve in an embodiment of the present invention.

[0025] Figure 3 This is a SEM comparison photo of the ITQ-2 molecular sieve in the embodiment of the present invention.

[0026] Figure 4 It is the adsorption data diagram of Example 2 and Comparative Example 1. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, tetraethylammonium hydroxide and water in a molar ratio of 1:2.5:2.4:80;

[0030] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of tetraethylammonium hydroxide, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it in an ultrasonic machine for 2h. Take it out and filter it after two hours. Dry it in an oven at 80℃ for four hours, take it out and put it in a muffle furnace at 540℃ for calcination for 2h to obtain the MCM-22 molecular sieve peeling sample, which is ITQ-2 molecular sieve.

[0031] Example 2

[0032] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, cyclohexylamine and water in a molar ratio of 1:2.5:2.4:80;

[0033] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of cyclohexylamine, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it in an ultrasonic machine for 2h. Take it out and filter it after two hours. Dry it in an oven at 80℃ for four hours, take it out and bake it in a muffle furnace at 540℃ for 2h, and then get the MCM-22 molecular sieve peeled sample, which is ITQ-2 molecular sieve.

[0034] Example 3

[0035] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, triethylamine and water in a molar ratio of 1:2.5:2.4:80;

[0036] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of triethylamine, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it in an ultrasonic machine for 2h. Take it out and filter it after two hours. Dry it in an oven at 80℃ for four hours, take it out and put it in a muffle furnace at 540℃ for calcination for 2h to obtain the MCM-22 molecular sieve peeling sample, which is ITQ-2 molecular sieve.

[0037] Example 4

[0038] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, ethanolamine and water in a molar ratio of 1:2.5:2.4:80;

[0039] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of ethanolamine, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it into an ultrasonic machine for 2h. Take it out and filter it after two hours. Dry it in an oven at 80℃ for four hours, take it out and put it into a muffle furnace at 540℃ for calcination for 2h to obtain the MCM-22 molecular sieve peeling sample, which is ITQ-2 molecular sieve.

[0040] Example 5

[0041] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, triethanolamine and water in a molar ratio of 1:2.5:2.4:80;

[0042] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of triethanolamine, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it in an ultrasonic machine for 2h. Take it out and filter it after two hours. Dry it in an oven at 80℃ for four hours, take it out and put it in a muffle furnace at 540℃ for calcination for 2h to obtain the MCM-22 molecular sieve peeling sample, which is ITQ-2 molecular sieve.

[0043] Example 6

[0044] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, 2,6-dimethylaniline and water in a molar ratio of 1:2.5:2.4:80;

[0045] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of triethanolamine, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it in an ultrasonic machine for 2h. Take it out and filter it after two hours. Dry it in an oven at 80℃ for four hours, take it out and put it in a muffle furnace at 540℃ for calcination for 2h to obtain the MCM-22 molecular sieve peeling sample, which is ITQ-2 molecular sieve.

[0046] Comparative Example 1

[0047] Sodium aluminate was used as the aluminum source required for the experiment, 30% silica sol was used as the silicon source, hexamethyleneimine HMI was used as the template agent, and sodium hydroxide was used as the alkali source. The MCM-22 molecular sieve was synthesized by reacting in a certain proportion.

[0048] Comparative Example 2

[0049] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, cyclohexylamine and water in a molar ratio of 1:2.5:1.4:80;

[0050] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of cyclohexylamine, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it in an ultrasonic machine for 2h. Take it out and filter it after two hours. Dry it in an oven at 80℃ for four hours, take it out and bake it in a muffle furnace at 540℃ for 2h, and then get the MCM-22 molecular sieve peeled sample, which is ITQ-2 molecular sieve.

[0051] Comparative Example 3

[0052] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, cyclohexylamine and water in a molar ratio of 1:2.5:3.4:80;

[0053] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of cyclohexylamine, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it in an ultrasonic machine for 2h. Take it out and filter it after two hours. Dry it in an oven at 80℃ for four hours, take it out and bake it in a muffle furnace at 540℃ for 2h, and then get the MCM-22 molecular sieve peeled sample, which is ITQ-2 molecular sieve.

[0054] Comparative Example 4

[0055] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, triethylamine and water in a molar ratio of 1:2.5:1.4:80;

[0056] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of triethylamine, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it. Put it into the ultrasonic machine for 2h. Take it out after two hours, filter it, dry it in an oven at 80℃ for four hours, take it out and put it into the muffle furnace at 540℃ for calcination for 2h, and then get the MCM-22 molecular sieve after peeling, which is ITQ-2 molecular sieve.

[0057] Comparative Example 5

[0058] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, triethylamine and water in a molar ratio of 1:2.5:3.4:80;

[0059] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of triethylamine, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it in an ultrasonic machine for 2h. Take it out and filter it after two hours. Dry it in an oven at 80℃ for four hours, take it out and put it in a muffle furnace at 540℃ for calcination for 2h to obtain the MCM-22 molecular sieve peeling sample, which is ITQ-2 molecular sieve.

[0060] Comparative Example 6

[0061] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, ethanolamine and water in a molar ratio of 1:2.5:1.4:80;

[0062] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of ethanolamine, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it into an ultrasonic machine for 2h. Take it out and filter it after two hours. Dry it in an oven at 80℃ for four hours, take it out and put it into a muffle furnace at 540℃ for calcination for 2h to obtain the MCM-22 molecular sieve peeling sample, which is ITQ-2 molecular sieve.

[0063] Comparative Example 7

[0064] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, ethanolamine and water in a molar ratio of 1:2.5:3.4:80;

[0065] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of ethanolamine, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it into an ultrasonic machine for 2h. Take it out and filter it after two hours. Dry it in an oven at 80℃ for four hours, take it out and put it into a muffle furnace at 540℃ for calcination for 2h to obtain the MCM-22 molecular sieve peeling sample, which is ITQ-2 molecular sieve.

[0066] Comparative Example 8

[0067] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, triethanolamine and water in a molar ratio of 1:2.5:1.4:80;

[0068] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of triethanolamine, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it into an ultrasonic machine for 2h. Take it out and filter it after two hours. Dry it in an oven at 80℃ for four hours, take it out and put it into a muffle furnace at 540℃ for calcination for 2h to obtain the MCM-22 molecular sieve peeling sample, which is ITQ-2 molecular sieve.

[0069] Comparative Example 9

[0070] The stripped MCM-22 molecular sieve comprises MCM-22 molecular sieve, hexadecyltrimethylammonium bromide, triethanolamine and water in a molar ratio of 1:2.5:3.4:80;

[0071] Weigh a certain amount of hexadecyltrimethylammonium bromide and add it to a three-necked flask equipped with a condenser, add an appropriate amount of water, and then start the magnetic stirrer. After stirring evenly, add a certain amount of triethanolamine, and finally add the weighed MCM-22 molecular sieve. Continue stirring at 80℃ for 16h. Take it out and cool it in an ultrasonic machine for 2h. Take it out and filter it after two hours. Dry it in an oven at 80℃ for four hours, take it out and put it in a muffle furnace at 540℃ for calcination for 2h to obtain the MCM-22 molecular sieve peeling sample, which is ITQ-2 molecular sieve.

[0072] Performance Testing

[0073] First, the MCM-22 molecular sieve after stripping is systematically characterized. Its crystal structure can be analyzed using X-ray diffraction (XRD) to evaluate the effect of the stripping process on its crystal phase. By comparing the XRD patterns of the samples before and after stripping, it can be observed whether new diffraction peaks appear or the intensity of the original diffraction peaks changes.

[0074] Secondly, the surface morphology of the sample was observed using a scanning electron microscope (SEM) to evaluate the particle morphology, surface smoothness and particle size distribution of the molecular sieve after stripping. At the same time, nitrogen adsorption-desorption experiments were performed to obtain important parameters such as the specific surface area, pore volume, and pore size distribution of MCM-22 after stripping. These data can intuitively reflect the effect of stripping on the pore structure of the molecular sieve.

[0075] MCM-22 molecular sieve is an acidic material with a special pore structure, which is widely used in the fields of catalysis and adsorption. The evaluation of the adsorption performance of MCM-22 molecular sieve has important scientific and engineering significance. First, it can provide the actual performance of molecular sieves in various reactions and separation processes, and provide a theoretical basis for optimizing the design and development of catalysts. Secondly, the high selectivity and thermal stability of MCM-22 make it superior in the treatment of complex mixtures, and the evaluation of adsorption capacity can help achieve efficient separation and enrichment of target molecules. In addition, by studying its adsorption behavior, we can also gain an in-depth understanding of the microstructural characteristics of molecular sieves and their interactions with molecules, thereby guiding the future development of new materials. Therefore, the adsorption evaluation of MCM-22 molecular sieves not only helps to improve its application performance, but also provides important data support for the scientific research of molecular sieve materials. Through the above characterizations and tests, we can not only gain an in-depth understanding of the changes in the physical and chemical properties of MCM-22 molecular sieves after stripping, but also provide an important theoretical basis and practical basis for its practical application in the field of catalysis.

[0076] The specific tests are as follows:

[0077] 1. XRD comparison diagram of ITQ-2 molecular sieve prepared in Example Figure 1 shown.

[0078] Depend on Figure 1 It can be seen that under the same experimental conditions, the ITQ-2 molecular sieve sample changes the amine source ratio to make the experimental ratio MCM-22:CTAB:amine source = 1:2.5:x (x = 1.4, 2.4, 3.4). It can be seen from the figure that in Examples 1, 3, 4 and 6, when MCM-22:CTAB:TPAOH = 1:2.5:2.4, the crystallinity is the best; in Examples 2 and 5, when MCM-22:CTAB:TPAOH = 1:2.5:3.4, the crystallinity is the best. When the ratio is relatively large or small, the diffraction characteristic peak is relatively low.

[0079] 2. BET comparison of ITQ-2 molecular sieve prepared in Example Figure 2 As shown. Figure 2 It can be seen that the adsorption curves of the ITQ-2 molecular sieve samples prepared in the examples are similar to the IV adsorption isotherm of the mesoporous material. When P / P0>0.7, the adsorption curve rises rapidly with the increase of pressure. However, unlike the MCM-22 molecular sieve, the hysteresis loop in the example samples is more obvious, because the MCM-22 molecular sieve after delamination forms some mesoporous channels, resulting in more obvious hysteresis phenomenon.

[0080] 3. SEM comparison photos of ITQ-2 molecular sieve prepared in Example Figure 3 As shown. Figure 3 It can be seen that the morphology of the ITQ-2 molecular sieve prepared in the embodiment is nano-plate-like crystals with a diameter of 100-400 nm, a thickness of 10-40 nm, and a silicon-aluminum ratio of 30-60.

[0081] 4. Take the MCM-22 molecular sieves prepared in Examples 1-6 and Comparative Examples 1-9, respectively, and perform XRD scanning to obtain their crystallinity.

[0082] The results are shown in Table 1.

[0083] Table 1 Crystallinity of MCM-22 molecular sieves in Examples 1-6 and Comparative Examples 1-9

[0084]

[0085]

[0086] As shown in Table 1, when the ratio of MCM-22:CTAB:amine source is 1:2.5:2.4, the specific surface area of ​​ITQ-2 molecular sieves prepared in Examples 1, 3, 4 and 6 is higher than that of the original MCM-22 molecular sieve powder before stripping, with the highest being 599 m 2 When the ratio of MCM-22:CTAB:amine source was 1:2.5:3.4, the specific surface area of ​​ITQ-2 molecular sieves prepared in Examples 2 and 5 was higher than that of the original MCM-22 molecular sieve powder before stripping, with the highest being 558 m 2 / g. The specific surface area obtained by stripping MCM-22 molecular sieves with cyclohexylamine, triethylamine, ethanolamine, triethanolamine and 2,6-dimethylaniline is greater than that of ITQ-2 molecular sieves stripped with TPAOH in the traditional stripping method, and the specific surface area is increased by nearly 50% relative to that of unstripped MCM-22 molecular sieves.

[0087] 5. The adsorption data of ITQ-2 molecular sieve prepared in Example 2 are as follows: Figure 4The ITQ-2 molecular sieve and the MCM-22 molecular sieve prepared in Example 2 and Comparative Example 1 were respectively tested for benzene molecule adsorption properties, and the adsorption data were obtained as follows.

[0088] The results are shown in Table 2.

[0089] Table 2 Adsorption results of MCM-22 molecular sieve in Example 1 and Comparative Example 1

[0090]

[0091]

[0092] As shown in Table 2, the adsorption capacity of benzene molecules by the ITQ-2 molecular sieve prepared in Example 2 is 2.288 mmol / g greater than that of the MCM-22 molecular sieve prepared in Comparative Example 1, and the adsorption capacity of benzene molecules by the ITQ-2 molecular sieve prepared in Example 2 is 3.608 mmol / g, and the adsorption capacity of benzene molecules by the ITQ-2 molecular sieve prepared in Example 2 is 1.320 mmol / g, indicating that the ITQ-2 prepared in Example 2 has a higher porosity and a better pore structure, and can accommodate more molecules. This may enable ITQ-2 to exhibit stronger selectivity and efficiency in specific applications.

[0093] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0094] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A stripped MCM-22 molecular sieve, characterized in that: The invention comprises the following ingredients: MCM-22 molecular sieve raw powder, hexadecyltrimethylammonium bromide, amine source and water; The mass ratio of the MCM-22 molecular sieve raw powder, hexadecyltrimethylammonium bromide, amine source and water is (0.2-1.2):(1.0-3.8):(1.4-4.0):(50-90).

2. The exfoliated MCM-22 molecular sieve according to claim 1, characterized in that: The amine source is tetrapropylammonium hydroxide.

3. The exfoliated MCM-22 molecular sieve according to claim 2, characterized in that: The amine source is cyclohexylamine.

4. The exfoliated MCM-22 molecular sieve according to claim 3, characterized in that: The amine source is triethylamine.

5. The exfoliated MCM-22 molecular sieve according to claim 4, characterized in that: The amine source is ethanolamine.

6. The exfoliated MCM-22 molecular sieve according to claim 5, characterized in that: The amine source is triethanolamine.

7. The exfoliated MCM-22 molecular sieve according to claim 6, characterized in that: The amine source is 2,6-dimethylaniline.

8. A method for preparing the stripped MCM-22 molecular sieve according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Weighing the raw materials according to the mass ratio of the raw materials described in any one of claims 1 to 7 and setting them aside; (2) first dissolving MCM-22 molecular sieve and hexadecyltrimethylammonium bromide in water, then adding an amine source dropwise and stirring to obtain a mixed slurry; (3) The mixed slurry is stirred, ultrasonicated, filtered, dried, and calcined in sequence to obtain the ITQ-2 molecular sieve.

9. The method for preparing the stripped MCM-22 molecular sieve according to claim 8, characterized in that: The stirring temperature in step (3) is 60-100° C. and the stirring time is 24-72 h; The drying temperature is 80°C.

10. The method for preparing the stripped MCM-22 molecular sieve according to claim 8, characterized in that: The calcination temperature in step (3) is 500-600° C. and the calcination time is 2-6 hours.

Images