Hierarchical pore molecular sieve and preparation method thereof

Abstract

The invention discloses a hierarchical pore molecular sieve and a preparation method thereof. The hierarchical pore molecular sieve comprises micropores and mesopores, the mesoporous aperture of the hierarchical pore molecular sieve is 6-12 nm; the hierarchical pore molecular sieve is a silicon-aluminum molecular sieve. The method comprises the following steps: adding a molecular sieve matrix into an alkali solution containing a surfactant and inorganic salt, carrying out alkali treatment, and carrying out ammonium ion exchange to obtain the hierarchical pore molecular sieve. According to the method, the molecular sieve is treated by adding the surfactant and the inorganic salt into the aqueous alkali, so that the pore size distribution and the pore volume of mesopores in the molecular sieve are effectively regulated and controlled, and the hierarchical pore molecular sieve with the mesopore size distribution of 6-12nm can be obtained.

Description

Technical Field

[0001] The present application relates to a hierarchical pore molecular sieve and a preparation method thereof, belonging to the field of inorganic material synthesis. Background Art

[0002] Zeolite molecular sieves are porous crystalline materials with remarkable hydrothermal stability, tunable acidity, and uniform pore sizes, playing a crucial role as catalysts in the petrochemical and refining industries. However, their narrow micropores may limit the transport of reactants and products, thereby hindering the full utilization of their active sites. To address the limitations of traditional zeolites, hierarchical pore molecular sieves with additional porosity have been developed.

[0003] Hierarchical pore molecular sieves are mainly achieved by two methods: the bottom-up method and the top-down method. The bottom-up method involves template strategies, such as hard templates or soft templates. Hard templates include using a template material to provide a physical structure for the formation of zeolite nanocrystals, while soft templates involve using surfactants or polymer templates to control the size, shape, and arrangement of zeolite nanocrystals. On the other hand, the advantage of the top-down method is that it is simple and cost-effective and does not require complex template strategies. It includes using acids or bases to etch microporous zeolites to create hierarchical porosity.

[0004] Alkali treatment is a cost-effective and scalable method for introducing interconnected mesopores into zeolite crystals. Since these methods are relatively simple, for example, soaking zeolites in 0.2 M NaOH at 65 °C for 30 minutes, this method shows compatibility with various zeolite topologies (including MFI, BEA, FER, and MOR). However, when the silica-alumina ratio of the molecular sieve is around 25 - 50, directly using alkalis such as NaOH for alkali treatment can only obtain mesopores with a pore size distribution of about 10 nm, and the mesopore size distribution cannot be adjusted. Summary of the Invention

[0005] To solve these problems, during the alkali treatment of high-silica molecular sieves, adding surfactants can protect the pore structure of the molecular sieve and improve the problem of disordered pores caused by excessive desilication. During the alkali treatment of high-silica molecular sieves, adding inorganic salts can adjust the mesopore size distribution of the molecular sieve. Mesopores of appropriate size can increase the diffusion rate of reaction molecules inside the material, thereby increasing the reaction rate and efficiency. Mesopores of appropriate size can increase the diffusion rate of molecules inside the material, thereby increasing the reaction rate and efficiency. Precise control of the pore size distribution can also maintain or enhance the thermal stability and mechanical strength of the material while increasing the porosity.

[0006] This application provides a hierarchical pore molecular sieve and a preparation method thereof. During the alkali treatment process, a surfactant and an inorganic salt are added, thereby effectively regulating the alkali treatment process. This improvement significantly enhances the diffusion ability of the microporous molecular sieve, and simultaneously successfully prepares a hierarchical pore molecular sieve with a larger pore volume while maintaining a specific crystal form. A hierarchical pore molecular sieve with a pore size distribution in the range of 6 - 12 nm can be obtained. In addition, this preparation process is not only simple to operate but also cost-effective, and has significant industrial application value.

[0007] In one aspect of this application, a hierarchical pore molecular sieve is provided. The hierarchical pore molecular sieve contains micropores and mesopores;

[0008] The mesopore aperture of the hierarchical pore molecular sieve is 6 - 12 nm;

[0009] The hierarchical pore molecular sieve is a silica-alumina molecular sieve.

[0010] Optionally, the micropore volume of the hierarchical pore molecular sieve is 0.08 cm 3 / g - 0.14 cm 3 / g;

[0011] The mesopore volume of the hierarchical pore molecular sieve is 0.26 cm 3 / g - 0.36 cm 3 / g;

[0012] The pore volume of the hierarchical pore molecular sieve is 0.3 - 0.5 cm 3 / g.

[0013] In another aspect of this application, a method for preparing the above-mentioned hierarchical pore molecular sieve is provided. The method includes:

[0014] Adding a molecular sieve parent to an alkali solution containing a surfactant and an inorganic salt for alkali treatment, and then performing ammonium ion exchange to obtain the hierarchical pore molecular sieve.

[0015] Optionally, the surfactant is selected from at least one of dodecyl trimethyl ammonium bromide, tetradecyl trimethyl ammonium bromide, hexadecyl trimethyl ammonium bromide, octadecyl trimethyl ammonium bromide;

[0016] The inorganic salt is selected from at least one of NaCl, KCl, NaBr, KBr, NaF, KF, NaNO3, KNO3, Na2SO4, K2SO4.

[0017] Optionally, in the alkali solution, the concentration of the surfactant is 0.05 - 0.3 mol / L;

[0018] In the alkali solution, the concentration of the inorganic salt is 0.05 - 0.3 mol / L.

[0019] Optionally, the concentration of the surfactant is independently selected from any value of 0.05 mol / L, 0.08 mol / L, 0.12 mol / L, 0.18 mol / L, 0.24 mol / L, 0.28 mol / L, 0.3 mol / L or a range value between any two of the above.

[0020] Optionally, the concentration of the inorganic salt is independently selected from any value of 0.05 mol / L, 0.10 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.30 mol / L or a range value between any two of the above.

[0021] Optionally, in the alkali solution, the concentration of the alkaline substance is 0.1 - 1 mol / L, wherein the alkaline substance is selected from at least one of NaOH, KOH, and Na2CO3.

[0022] Optionally, the alkali solution is a sodium hydroxide solution.

[0023] Optionally, the concentration of the alkaline substance is independently selected from any value of 0.1 mol / L, 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L, 1 mol / L or a range value between any two of the above.

[0024] Optionally, the molecular sieve matrix is selected from at least one of ZSM-5 molecular sieve, ZSM-11 molecular sieve, and mordenite;

[0025] The silica-alumina ratio of the molecular sieve matrix ≥ 20.

[0026] Optionally, the molecular sieve is a ZSM-5 molecular sieve.

[0027] Optionally, the solid-liquid ratio of the molecular sieve matrix to the alkali solution is 1:10 - 50 g / ml.

[0028] Optionally, the upper limit of the solid-liquid ratio of the molecular sieve to the alkali solution is independently selected from 1:30 g / ml, 1:40 g / ml, 1:50 g / ml, and the lower limit is independently selected from 1:10 g / ml, 1:20 g / ml, 1:30 g / ml.

[0029] Optionally, the alkali treatment includes:

[0030] Add the molecular sieve matrix to the alkaline solution containing the surfactant and inorganic salt, stir, perform alkaline treatment at 30-90°C for 10-60 minutes, centrifuge at 4000 r / min for 5 minutes, dry at 60-120°C for 10-24 hours, and calcine at 500-700°C for 2-8 hours to obtain the alkali-treated molecular sieve.

[0031] Optionally, the upper limit of the temperature of the alkaline treatment is independently selected from 60°C, 70°C, 75°C, 80°C, 90°C, and the lower limit is independently selected from 30°C, 40°C, 45°C, 50°C, 60°C; the upper limit of the time of the alkaline treatment is independently selected from 35 minutes, 40 minutes, 50 minutes, 60 minutes, and the lower limit is independently selected from 10 minutes, 20 minutes, 30 minutes, 35 minutes.

[0032] Optionally, the upper limit of the temperature of the drying I is independently selected from 90°C, 100°C, 110°C, 120°C, and the lower limit is independently selected from 60°C, 70°C, 80°C, 90°C; the upper limit of the time of the drying I is independently selected from 16 hours, 20 hours, 24 hours, and the lower limit is independently selected from 10 hours, 12 hours, 16 hours.

[0033] Optionally, the upper limit of the temperature of the calcination I is independently selected from 600°C, 650°C, 700°C, and the lower limit is independently selected from 500°C, 550°C, 600°C; the upper limit of the time of the calcination I is independently selected from 5 hours, 6 hours, 7 hours, 8 hours, and the lower limit is independently selected from 2 hours, 3 hours, 4 hours, 5 hours.

[0034] Optionally, the ammonium ion exchange includes the following steps:

[0035] Add the alkali-treated molecular sieve to the ammonium salt solution, stir and exchange at 70-90°C for 1-3 hours to obtain a suspension system, and perform 2-6 repeated exchanges after centrifugal separation; centrifuge at 4000 r / min for 5 minutes, dry at 100-120°C for 10-24 hours, and calcine at 400-600°C for 2-5 hours to obtain the hierarchical pore molecular sieve;

[0036] The ammonium salt is at least one of ammonium nitrate and ammonium chloride;

[0037] In the ammonium salt solution, the concentration of the ammonium salt is 0.2-1 mol / L

[0038] Optionally, the concentration of the ammonium salt is selected from any value among 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L, 1 mol / L or the range value between any two of them.

[0039] Optionally, the upper limit of the ammonium exchange temperature is independently selected from 60°C, 70°C, 80°C, 90°C, and the lower limit is independently selected from 30°C, 40°C, 50°C, 60°C; the upper limit of the ammonium exchange time is independently selected from 2 hours, 2.5 hours, 3 hours, and the lower limit is independently selected from 1 hour, 1.5 hours, 2 hours; the upper limit of the number of ammonium exchange repetitions is independently selected from 4 times, 5 times, 6 times, and the lower limit is independently selected from 2 times, 3 times, 4 times.

[0040] Optionally, the upper limit of the temperature of the second drying is independently selected from 110°C, 115°C, 120°C, and the lower limit is independently selected from 100°C, 105°C, 110°C; the upper limit of the time of the second drying is independently selected from 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, and the lower limit is independently selected from 10 hours, 12 hours, 14 hours, 16 hours.

[0041] Optionally, the upper limit of the temperature of the second calcination is independently selected from 500°C, 550°C, 600°C, and the lower limit is independently selected from 400°C, 450°C, 500°C; the lower limit of the time of the second calcination is independently selected from 2 hours, 3 hours, and the upper limit is independently selected from 4 hours, 5 hours.

[0042] As a specific method, the method for preparing the hierarchical pore molecular sieve includes the following steps:

[0043] a) Obtain an alkaline solution containing a surfactant and an inorganic salt;

[0044] b) Add the molecular sieve to the alkaline solution obtained in step a), stir, then wash by centrifugation I, dry I, and calcine I to obtain the alkali-treated molecular sieve;

[0045] c) Add the alkali-treated molecular sieve to an ammonium salt solution with a certain concentration, stir and exchange at a certain temperature for a certain time to obtain a suspension system, and perform repeated exchange after centrifugal separation;

[0046] d) Centrifuge and wash the suspension system obtained in step c) by centrifugation II, dry II, and calcine II to obtain the hierarchical pore molecular sieve.

[0047] Optionally, the solid-liquid ratio of the alkali-treated molecular sieve to the ammonium salt solution is 1:10 - 30 g / ml.

[0048] Optionally, the yield of the hierarchical pore molecular sieve is above 70%.

[0049] The beneficial effects that can be produced by this application include:

[0050] 1) The method for preparing the hierarchical pore molecular sieve provided by the present invention is simple to prepare and low in cost.

[0051] 2) The method for preparing the hierarchical zeolite catalyst provided by the present invention can effectively regulate the mesopore size (6 - 12 nm) and pore volume (0.3 - 0.5 cm 3 / g) of the hierarchical zeolite.

[0052] 3) By treating the zeolite with a surfactant and an inorganic salt added to an alkaline solution in this application, the pore size distribution and pore volume of the mesopores in the zeolite are effectively regulated, and hierarchical zeolites with a mesopore size distribution of 6 - 12 nm can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 For Samples 1 # , 2 # , 3 # in Examples 1, 2, and 3 of this application * and Sample 2 in Comparative Example 2 a) nitrogen adsorption - desorption isotherm and b) secondary pore BJH pore size distribution curve (where # is Sample 1 in Example 1 ; # is Sample 2 in Example 2 # ; ● is Sample 3 in Example 3 * ; ■ is Sample 2 in Comparative Example 2 DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] The following describes this application in detail with reference to the embodiments, but this application is not limited to these embodiments.

[0055] The method for preparing the hierarchical zeolite includes the following steps:

[0056] Adding the parent zeolite to an alkaline solution containing a surfactant and an inorganic salt for alkali treatment, and then performing ammonium ion exchange to obtain the hierarchical zeolite; the parent zeolite is ZSM - 5 zeolite.

[0057] The alkali treatment includes the following steps:

[0058] a) Obtaining an alkaline solution containing a surfactant and an inorganic salt;

[0059] b) Adding the parent zeolite to the solution obtained in step a), stirring and reacting at a certain temperature for a period of time, followed by centrifugation I, washing, drying I, and calcination I.

[0060] The ammonium ion exchange includes the following steps:

[0061] c) Adding the alkali - treated zeolite to an ammonium salt solution, stirring and exchanging at a certain temperature for a certain time to obtain a suspension system, and performing repeated exchange after centrifugation;

[0062] d) Centrifuge and wash the suspension system obtained in step c), dry it II, and calcine it II to obtain the hierarchical porous molecular sieve.

[0063] Unless otherwise specified, the raw materials and catalysts in the examples of this application are all purchased through commercial channels. Among them, the molecular sieves are purchased from Tianjin Nankai Catalyst Co., Ltd., and the ZSM-5 molecular sieves of the MFI type have nominal silica-alumina ratios (Si / Al) of 200, 350, 500, 1000, and 1500.

[0064] Characterization of specific surface area and pore size distribution

[0065] A Micromeritics ASAP 2460 physical adsorption analyzer was used for specific surface area and pore size distribution characterization.

[0066] The analysis conditions for specific surface area and pore volume are as follows: 0.1 g of the catalyst was loaded into a quartz adsorption tube, vacuum-treated at 350 °C for 12 h to remove the moisture and impurities adsorbed by the molecular sieve, and a nitrogen adsorption / desorption experiment was carried out at a temperature of 77.4 K. The Brunauer-Emmett-Teller (BET) equation was used to calculate the micropore specific surface area of the sample, and the t-plot method was used to calculate the micropore specific surface area, micropore volume, mesopore specific surface area, and mesopore volume of the molecular sieve sample. The BJH method was used to obtain the pore size distribution of the sample.

[0067] Preparation of hierarchical porous molecular sieve in Example 1

[0068] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH, 0.1 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaF, heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge I at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. The obtained molecular sieve solid was dried I at 120 °C for 12 hours and calcined I at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge II at 4000 r / min for 5 minutes and wash, dry II at 120 °C for 12 hours, and finally calcine II at 550 °C for 3 hours. The obtained solid is the hierarchical porous molecular sieve, denoted as sample 1 # 。

[0069] Preparation of hierarchical porous molecular sieve in Example 2

[0070] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH, 0.1 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt Na2SO4. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 2 # 。

[0071] Preparation of Hierarchical Pore Molecular Sieve in Example 3

[0072] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH, 0.1 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaBr. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 3 # 。

[0073] Preparation of Hierarchical Pore Molecular Sieve in Example 4

[0074] Take 180 ml of an aqueous solution containing 0.1 mol / L of NaOH, 0.2 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaF. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 4 # 。

[0075] Preparation of Hierarchical Pore Molecular Sieve in Example 5

[0076] Take 180 ml of an aqueous solution containing 0.1 mol / L of NaOH, 0.2 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaBr. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 5 # 。

[0077] Preparation of Hierarchical Pore Molecular Sieve in Example 6

[0078] Take 180 ml of an aqueous solution containing 0.1 mol / L of NaOH, 0.2 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt Na2SO4. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 6 # 。

[0079] Preparation of Hierarchical Pore Molecular Sieve in Example 7

[0080] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH, 0.2 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaF. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 7 # 。

[0081] Preparation of Hierarchical Pore Molecular Sieve in Example 8

[0082] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH, 0.2 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of the inorganic salt NaBr. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes for washing, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 8 # 。

[0083] Preparation of Hierarchical Pore Molecular Sieve in Example 9

[0084] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH, 0.2 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of the inorganic salt Na2SO4. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes for washing, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 9 # 。

[0085] Preparation of Hierarchical Pore Molecular Sieve in Example 10

[0086] Take 180 ml of an aqueous solution containing 0.1 mol / L of NaOH, 0.1 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaF. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 1000), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours. Take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes for washing, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 10 # 。

[0087] Preparation of Hierarchical Pore Molecular Sieve in Example 11

[0088] Take 180 ml of an aqueous solution containing 0.1 mol / L of NaOH, 0.1 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaBr. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 1000), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours. Take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes for washing, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 11 # 。

[0089] Preparation of Hierarchical Pore Molecular Sieve in Example 12

[0090] Take 180 ml of an aqueous solution containing 0.1 mol / L of NaOH, 0.1 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt Na2SO4. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 1000), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes for washing, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 12 # 。

[0091] Preparation of Hierarchical Pore Molecular Sieve in Example 13

[0092] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH, 0.2 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaF. Heat it in a water bath to 80 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 80 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes for washing, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 13 # 。

[0093] Preparation of Hierarchical Pore Molecular Sieve in Example 14

[0094] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH, 0.2 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of the inorganic salt NaBr. Heat it in a water bath to 80 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 80 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 14 # 。

[0095] Preparation of Hierarchical Pore Molecular Sieve in Example 15

[0096] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH, 0.2 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of the inorganic salt Na2SO4. Heat it in a water bath to 80 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 80 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 15 # 。

[0097] Preparation of Hierarchical Pore Molecular Sieve in Example 16

[0098] Take 180 ml of an aqueous solution containing 0.3 mol / L of NaOH, 0.2 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaF. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 200), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours. Take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 16 # 。

[0099] Preparation of Hierarchical Pore Molecular Sieve in Example 17

[0100] Take 180 ml of an aqueous solution containing 0.3 mol / L of NaOH, 0.2 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaBr. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 200), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours. Take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 17 # 。

[0101] Preparation of Hierarchical Pore Molecular Sieve in Example 18

[0102] Take 180 ml of an aqueous solution containing 0.3 mol / L of NaOH, 0.2 mol / L of cetyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt Na2SO4. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 200), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 18 # 。

[0103] Preparation of hierarchical pore molecular sieve in Example 19

[0104] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH, 0.1 mol / L of decyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaF. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 19 # 。

[0105] Preparation of hierarchical pore molecular sieve in Example 20

[0106] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH, 0.1 mol / L of dodecyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaF. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours. Take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes for washing, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 20 # 。

[0107] Preparation of Hierarchical Pore Molecular Sieve in Example 21

[0108] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH, 0.1 mol / L of tetradecyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaF. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours. Take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes for washing, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 21 # 。

[0109] Preparation of Hierarchical Pore Molecular Sieve in Example 22

[0110] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH, 0.1 mol / L of octadecyltrimethylammonium bromide, and 0.2 mol / L of inorganic salt NaF. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours. Take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve treated with alkali, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 22 # 。

[0111] Comparative Example 1

[0112] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH and 0.2 mol / L of cetyltrimethylammonium bromide. Heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours. Take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve treated with alkali, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 1 * 。

[0113] Comparative Example 2

[0114] Take 180 ml of an aqueous solution containing 0.2 mol / L of NaOH and 0.1 mol / L of cetyltrimethylammonium bromide, heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 500), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 2 * 。

[0115] Comparative Example 3

[0116] Take 180 ml of an aqueous solution containing 0.1 mol / L of NaOH and 0.2 mol / L of cetyltrimethylammonium bromide, heat it in a water bath to 65 °C, add 6.00 g of ZSM-5 molecular sieve (Si / Al = 1000), stir at 65 °C for 30 minutes, then centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 hours and calcine it at 550 °C for 5 hours; take 60 ml of 0.8 mol / L ammonium nitrate solution, preheat it to 85 °C, add 3.0 g of the molecular sieve obtained by alkali treatment, stir and exchange for 2 hours, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 hours, and finally calcine at 550 °C for 3 hours. The obtained solid is the hierarchical pore molecular sieve, denoted as sample 3 * 。

[0117] Sample 1 in Example 1 # , its mesopore pore size distribution is around 6 nm; sample 2 in Example 2 # , its mesopore pore size distribution is around 8 nm; sample 3 in Example 3 # , its mesopore pore size distribution is around 10 nm; sample 2 in Comparative Example 2 * , its mesopore pore size distribution is around 10 nm. Sample 1 in Example 1 # , its pore volume is 0.46 cm 3 / g; sample 2 in Example 2 # , its pore volume is 0.46 cm 3 / g; sample 3 in Example 3 # , its pore volume is 0.45 cm 3 / g; Sample 2 in Comparative Example 2 * , with a pore volume of 0.36 cm 3 / g.

[0118] In industrial catalysis, mesoporous molecular sieves with different pore sizes are of great significance. Larger pore-sized molecular sieves help accommodate large molecules, improve the diffusion performance of reactants within the catalyst, and thus optimize macromolecular catalytic reactions. On the contrary, smaller pore sizes are more suitable for small molecule reactions because they provide a larger surface area and a higher exposure of active centers, which helps enhance the adsorption and catalytic activity of small molecules. Therefore, by achieving mesoporous regulation of different pore sizes, it is helpful to optimize the design of the catalyst according to the size of the specific reactants, and improve the reaction efficiency and selectivity.

[0119] As described above, these are only several embodiments of the present application, and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, makes some changes or modifications using the technical content disclosed above, which are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A hierarchical pore molecular sieve, characterized in that, The hierarchical pore molecular sieve comprises micropores and mesopores; The mesopore aperture of the hierarchical pore molecular sieve is 6 - 12 nm; The hierarchical pore molecular sieve is a silica-alumina molecular sieve.

2. The hierarchical pore molecular sieve according to claim 1, characterized in that, The micropore volume of the hierarchical zeolite is 0.08 cm 3 / g to 0.14 cm 3 / g; The mesopore volume of the hierarchical zeolite is 0.26 cm 3 / g to 0.36 cm 3 / g; The pore volume of the hierarchical zeolite molecular sieve is 0.3 to 0.5 cm 3 / g.

3. A method for preparing the hierarchical pore molecular sieve according to any one of claims 1 to 2, characterized in that, The method comprises: Adding a molecular sieve mother body into an alkaline solution containing a surfactant and an inorganic salt for alkali treatment, and then performing ammonium ion exchange to obtain the hierarchical pore molecular sieve.

4. The method according to claim 3, characterized in that, The surfactant is selected from at least one of dodecyl trimethyl ammonium bromide, tetradecyl trimethyl ammonium bromide, hexadecyl trimethyl ammonium bromide, octadecyl trimethyl ammonium bromide; The inorganic salt is selected from at least one of NaCl, KCl, NaBr, KBr, NaF, KF, NaNO3, KNO3, Na2SO4, K2SO4; 5. The method according to claim 3, characterized in that, In the alkaline solution, the concentration of the surfactant is 0.05 - 0.3 mol / L; In the alkaline solution, the concentration of the inorganic salt is 0.05 - 0.3 mol / L.

6. The method according to claim 3, characterized in that, In the alkaline solution, the concentration of the alkaline substance is 0.1 - 1 mol / L, wherein the alkaline substance is selected from at least one of NaOH, KOH, Na2CO3; 7. The method according to claim 3, characterized in that, The molecular sieve mother body is selected from at least one of ZSM-5 molecular sieve, ZSM-11 molecular sieve, mordenite; Preferably, the silica-alumina ratio of the molecular sieve mother body ≥ 20.

8. The method according to claim 3, characterized in that, The solid-liquid ratio of the molecular sieve mother body to the alkaline solution is 1:10 - 50 g / ml.

9. The method according to claim 3, characterized in that, The alkali treatment comprises: Adding the molecular sieve mother body into the alkaline solution containing the surfactant and the inorganic salt, stirring, performing alkali treatment at 30 - 90 °C for 10 - 60 minutes, centrifuging at 4000 r / min for 5 minutes, drying at 60 - 120 °C for 10 - 24 hours, calcining at 500 - 700 °C for 2 - 8 hours to obtain the alkali-treated molecular sieve.

10. The method according to claim 9, characterized in that, The ammonium ion exchange comprises the following steps: Adding the alkali-treated molecular sieve into an ammonium salt solution, stirring and exchanging at 70 - 90 °C for 1 - 3 hours to obtain a suspension system, performing 2 - 6 times of repeated exchange after centrifugal separation; centrifuging at 4000 r / min for 5 minutes, drying at 100 - 120 °C for 10 - 24 hours, calcining at 400 - 600 °C for 2 - 5 hours to obtain the hierarchical pore molecular sieve; The ammonium salt is at least one of ammonium nitrate and ammonium chloride; In the ammonium salt solution, the concentration of the ammonium salt is 0.2 - 1 mol / L; The solid-liquid ratio of the alkali-treated molecular sieve to the ammonium salt solution is 1:10 - 30 g / ml.

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