CN109665539B

CN109665539B - Modified Y molecular sieve with regular mesopore-micropore and preparation method thereof

Info

Publication number: CN109665539B
Application number: CN201710955119.8A
Authority: CN
Inventors: 付强; 慕旭宏; 李永祥; 张成喜; 胡合新; 舒兴田
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2017-10-13
Filing date: 2017-10-13
Publication date: 2020-10-27
Anticipated expiration: 2037-10-13
Also published as: CN109665539A

Abstract

The present disclosure relates to a modified Y molecular sieve with regular mesopores-micropores and its preparationMethod for preparing modified Y molecular sieve skeleton SiO₂/Al₂O₃The molar ratio of (A) to (B) is 5.0 to 6.0, and the specific surface area of the micropores is 400 to 600m²The volume of the micropores is 0.25-0.35 cm³The mesoporous specific surface area is 30-200 m²The mesoporous volume is 0.07-0.85 cm³The mesoporous aperture is 2.0-6.0 nm, and the content of sodium oxide in the modified Y molecular sieve is not more than 0.1 wt% based on the total weight of the modified Y molecular sieve. The method introduces the mesopores while retaining the micropores of the Y molecular sieve, has good connectivity between the mesopores and the micropores, and is favorable for macromolecular diffusion.

Description

Modified Y molecular sieve with regular mesopore-micropore and preparation method thereof

Technical Field

The disclosure relates to the field of molecular sieves, in particular to a modified Y molecular sieve with regular mesopores and micropores and a preparation method thereof.

Background

At the end of the fifty years, Milton and Breck successfully synthesized Y-type molecular sieves. Because of SiO in the structure of the Y-type molecular sieve₂With Al₂O₃The ratio of the molecular sieve is larger than that of the X-type molecular sieve, so that the thermal stability and the hydrothermal stability are improved. In the early seventies, Grace company developed a guide agent method for synthesizing NaY molecular sieve, water glass was used as a raw material to replace expensive silica sol, the process was simplified, and the growth cycle was shortened, so that the NaY molecular sieve was rapidly and widely usedThe method is applied to the field of petrochemical industry, in particular to petroleum cracking catalysis. Of the hundreds of molecular sieves that have been developed so far, the largest amount used industrially is the Y-type molecular sieve. At present, the synthesis of the Y-type molecular sieve mainly adopts a crystal gel method in industry. Due to the use and improvement of the crystal seed gel, the synthesis and crystallization time of the Y-type molecular sieve is greatly shortened, and a foundation is laid for the industrialization of the Y-type molecular sieve.

The industrial application and development put higher demands on the synthesis of the molecular sieve and the product performance thereof, which in turn promotes the intensive research of the molecular sieve synthesis technology. The higher demand for the synthesis of Y-type molecular sieves has mainly focused on increasing their internal diffusion capacity.

The small-grain Y-type molecular sieve has larger external surface area and higher in-crystal diffusion rate, and shows more excellent performance than the conventional grain Y-type molecular sieve in the aspects of improving the macromolecule conversion capacity, reducing the secondary cracking of products, reducing the coking of catalysts and the like, so the synthesis research of the small-grain Y-type molecular sieve becomes a hotspot. The Y-type molecular sieves synthesized by conventional methods typically have a crystallite size of about 1000nm, while small crystallites can reach even nanoscale (<100nm) crystallite sizes, and there are still few reports on this synthesis.

The preparation of molecular sieves with hierarchical pore structures is yet another solution. In designing catalysts, it is desirable to both maximize the accessibility of the active sites to fully develop their catalytic potential and to minimize the pore space of the zeolite for higher catalytic activity. There is therefore a need to find an optimum balance between active site accessibility and active site bulk density, i.e. to create an optimum hierarchical pore distribution in the catalytic material. The hierarchical pore molecular sieve is prepared, and the function of the hierarchical pore structure is really realized: graded pore distribution and graded acid strength distribution. The methods for preparing the hierarchical pore molecular sieves reported at present can be mainly divided into a "constructive" method and a "destructive" method. The "constructive" method is also called a template method, and is classified into a hard template method and a soft template method according to the type of template. The medium pore volume of the multilevel pore structure zeolite synthesized by using the hard template is generally larger, the pore distribution is wider, and the hard template and the molecular sieve are synthesized into the original zeoliteThere is no direct interaction between the materials, and the pore volume and pore size are completely dependent on the particle size and dispersion of the hard template. The mesoporous volume of the multilevel pore structure zeolite synthesized by using the soft template is smaller than that of a sample synthesized by using a hard template, and is generally concentrated at 0.2-0.5 cm³The mesoporous pore distribution is narrow between the/g. The common soft membrane plate mainly comprises a high molecular polymer, organosilane, a surfactant and the like, and the cost of synthesizing a sample by using the soft membrane plate is high. The destructive method is mainly divided into dealumination modification and desilication modification. Typical dealumination methods include hydrothermal dealumination and acid treatment dealumination. Dealumination modification can generate a large amount of secondary mesoporous defects in the molecular sieve framework. For the silicon-aluminum molecular sieve with low silicon-aluminum ratio, dealumination treatment is a simple and easy method for forming intracrystalline mesopores. For Y zeolite, the method for preparing hierarchical pores, which is currently the most widely used industrially, is to prepare mesopores by hydrothermal treatment, which has easy operability and low industrial scale-up cost, but like other dealumination modifications, inevitably introduces closed mesopore cavities. Therefore, the modification method has no obvious advantages for improving the mass transfer performance of the molecular sieve.

In the synthesis of the hierarchical pore zeolite molecular sieve, another research focus is to utilize organosilane to regulate the crystallization of the zeolite molecular sieve, and the long-chain alkyl silane coupling agent can limit the growth of the zeolite molecular sieve and synthesize the nano zeolite. The zeolite molecular sieve with disordered mesoporous channels in the crystal can be successfully synthesized by adopting a partially silanized polymer as a template. In 2006, Serrano et al found that organosilanes, which are stable with conventional silica-alumina species under hydrothermal conditions during synthesis of Zeolites, can limit the growth of zeolite molecular sieves (Serrano D.P., AguaadoJ., Escora J.M., Rodriguez J.M., Peral A: structural Zeolite with enhanced engineering and Catalytic Properties Synthesized from organic functionalized feeds [ J ] chem.Mater.,2006,18: 2462-. It has been found that organosilanes can limit the growth of zeolite molecular sieves, and that organosilanes can form with conventional silicon aluminum species during synthesis of zeolites and are stable in multilevel channels under hydrothermal conditions. According to the method, organosilane is added into pre-crystallized zeolite molecular sieve synthesis gel to synthesize Si-C bonds of the zeolite molecular sieve with disordered mesoporous channels in crystals, and the growth of the zeolite molecular sieve is limited, so that the aggregate of the nano zeolite molecular sieve is obtained. The prepared nano zeolite aggregate has small particle size and a large amount of mesopores. The main objective of the process is to be able to synthesize zeolitic molecular sieves with nanosized features in high yields using organosilane growth-limiting methods.

In 2006, the concept of organosilane growth restriction on Zeolite molecular sieves was further applied to the synthesis of hierarchical pore Zeolite molecular sieves, and Pinnavaia et al synthesized MFI Zeolite molecular sieves containing intra-crystalline mesoporous channels using partially silanized polymers as templates, the resulting Zeolite molecular sieves containing a controllable mesoporous structure of 2-3nm, with the mesopore size depending on the molecular weight of the polymer template used (Wang h.and Pinnavaia t.j.: MFI Zeolite with Small and unified intra crystal memories. In the synthesis process, controlling the silanization degree of the polymer is an important factor for synthesizing the mesoporous zeolite single crystal. In particular, Ryoo et al reported the use of designed silanized surfactants as soft templates for the synthesis of hierarchical zeolite molecular sieves. As a result, it was found that the silanized surfactant can be directed to the synthesis of mesoporous zeolites, which utilize TPOAC (C)₁₈H₃₇N⁺(CH₃)₂(CH₂)₃Si(OCH₃)₃Cl^-) And the like as templates to successfully synthesize mesoporous ZSM-5, A-type zeolite and aluminum phosphate series nano zeolite molecular sieve aggregates. They believe that the presence of organosilanes forms Si-C bonds with silicon species during crystallization of the zeolitic molecular sieve which are very stable under hydrothermal conditions, thereby limiting the nucleation and crystallization steps of the zeolitic molecular sieve (Choi M., Cho H.S., Srivastavar., Venkatesan C., Choi D.H., Ryoo R., Amphiphilic organic direct Synthesis of Crystalline Zeolite with Tunable mesoporous silica [ J ] J].NatureMaterials,2006,5:718-723)。

CN102774854A discloses a method for synthesizing a meso-microporous NaY molecular sieve, which uses a reaction product substituted by NH group polymer and aliphatic epoxy silane amine as a template agent, and adds the template agent in the process of synthesizing a Y-type molecular sieve to generate a meso-microporous structure in situ.

CN102936017B discloses a mesoporous nano zeolite aggregate and a preparation method thereof. The method comprises the steps of firstly silanizing the surface of nano silicon dioxide, then adding a template agent and an aluminum source into the silicon source, and carrying out hydrothermal crystallization under a certain condition to obtain the Beta nano zeolite aggregate formed by self-polymerization of nano zeolite grains with intragranular mesopores. Overcomes the defect that the nano Beta zeolite is not easy to separate in the synthesis and use processes.

CN102874836A discloses a method for synthesizing a mesoporous A-type molecular sieve. The preparation method specifically comprises the steps of taking a mixture of a multiwalled carbon nanotube and a silane coupling agent after bridging as a template agent, adding another silane coupling agent into a silicon source, treating the mixture under a heating condition to react, transferring the mixture into an aluminum source after the reaction is completed, stirring, crystallizing, filtering, washing, drying, and removing the template agent through high-temperature calcination to obtain the mesoporous A-type molecular sieve.

In the above patents, the template agent is added during the synthesis of the molecular sieve, and the micropores and mesopores are prepared in situ. However, when the method is used for hydrothermal synthesis of the Y molecular sieve, P-type mixed crystals are easily generated, synthesis of the Y molecular sieve is affected, and generation of micropores and mesopores is further affected.

Before the application of the Y-type molecular sieve, the Y-type molecular sieve is modified to obtain the molecular sieve with different SiO₂/Al₂O₃Specific, acidic and pore structure molecular sieves. Modification treatment of molecular sieves is usually achieved by changing the content of aluminum, wherein acid dealumination is an important method for modifying Y-type molecular sieves. The acid treatment condition is mild, and the non-framework aluminum in the molecular sieve can be selectively removed without damaging the structure of the molecular sieve. However, part of non-framework aluminum which is difficult to remove can not be effectively and uniformly removed by adopting common acid treatment, and if the acid concentration is increased, part of framework aluminum can be removed, so that the modified molecular sieve is damaged in structure, the crystallinity is reduced, the acid distribution is unreasonable, and the catalytic performance is directly reduced. The small-grain molecular sieve has small grains and poor structural stabilityThe structure is easier to be damaged in the post-treatment process, and the crystallinity is greatly reduced. Treatment of molecular sieves with silicalites is another modification method. CN1382632A discloses a method for ultra-stabilizing small-grain Y-type zeolite, which is obtained by contacting and washing silicon tetrachloride dry gas with small-grain NaY zeolite, and because the thermal and hydrothermal stability of the raw material is poor, the method adopts a gas-phase dealuminization silicon-supplementing mode to treat a molecular sieve, the thermal and hydrothermal stability of the product is poor, and the activity is low; in addition, the gas phase treatment method has the defects of small batch, high energy consumption and the like in industrial production.

Disclosure of Invention

The purpose of the disclosure is to provide a modified Y molecular sieve with regular mesopores-micropores and a preparation method thereof.

To achieve the above object, a first aspect of the present disclosure: provides a modified Y molecular sieve with regular mesopores-micropores, and the skeleton SiO of the modified Y molecular sieve₂/Al₂O₃The molar ratio of (A) to (B) is 5.0 to 6.0, and the specific surface area of the micropores is 400 to 600m²The volume of the micropores is 0.25-0.35 cm³The mesoporous specific surface area is 30-200 m²The mesoporous volume is 0.07-0.85 cm³The mesoporous aperture is 2.0-6.0 nm, and the content of sodium oxide in the modified Y molecular sieve is not more than 0.1 wt% based on the total weight of the modified Y molecular sieve.

In a second aspect of the present disclosure: there is provided a process for preparing the modified Y molecular sieve of claim 1, the process comprising:

a. mixing sodium metaaluminate with water glass to obtain a first mixture, dynamically aging and standing for aging the first mixture, and then mixing the first mixture with water to obtain a second mixture, wherein the second mixture comprises Na in terms of oxide and mol₂O：A1₂O₃：SiO₂：H₂O＝(6～25)：1：(6～25)：(200～400)；

b. Mixing the second mixture obtained in the step a with water, a silicon source and an aluminum source to obtain a third mixture;

c. b, performing hydrothermal crystallization on the third mixture obtained in the step b, and collecting a solid obtained after the hydrothermal crystallization;

d. re-pulping the solid obtained in the step c, mixing the obtained slurry with a silane coupling agent and a quaternary ammonium salt surfactant, and reacting for 4-48 hours at the temperature of 60-200 ℃ and under the autogenous pressure to obtain a NaY molecular sieve;

e. and d, sequentially carrying out ammonium sodium reduction, hydrothermal treatment and dealumination and silicon supplement on the NaY molecular sieve obtained in the step d to obtain the modified NaY molecular sieve.

Optionally, in step a, the dynamic aging comprises: stirring and aging for 5-48 hours at 15-60 ℃; the standing and aging comprises the following steps: standing and aging for 5-48 hours at 15-60 ℃.

Optionally, in step b, the composition of the third mixture is Na, calculated as oxides and on a molar basis₂O：A1₂O₃：SiO₂：H₂O＝(2～6)：1：(8～20)：(200～400)。

Optionally, in step b, the silicon source is at least one selected from water glass, silica sol, silica gel and silica white; the aluminum source is at least one selected from sodium metaaluminate, aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum hydroxide and pseudo-boehmite.

Optionally, the aluminum element in the second mixture accounts for 3-30% of the aluminum element in the third mixture in terms of elements and moles.

Optionally, in step c, the conditions of the hydrothermal crystallization are as follows: the temperature is 90-100 ℃, and the time is 15-48 hours.

Optionally, in step d, with A1₂O₃The molar ratio of the slurry to amphiphilic organosilane, surfactant calculated as 1: (0.04-10): (0.04-10).

Optionally, in step d, the silane coupling agent is of the formula R¹Si(L¹)₃A compound of formula (I), L¹Is selected from methoxy, ethoxy, chlorine and methoxyethoxyOne of (1), R¹Is one selected from phenyl, C1-C22 chain alkyl, C1-C22 alkenyl and terminal substituted alkyl, wherein the terminal substituted alkyl is at least one selected from chlorine, amino, epoxy, vinyl and methacryloxy.

Optionally, in the step d, the silane coupling agent is at least one selected from the group consisting of octadecyltrimethoxysilane, vinyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane and 3- (2, 3-glycidoxy) propyltrimethoxysilane.

Optionally, in step d, the quaternary ammonium surfactant is of the formula R²N(R³)₃A compound represented by X, R²Is C8-C22 alkanyl, R³Is a hydrocarbyl group, and X is halogen or hydroxyl.

Optionally, in step d, the quaternary ammonium salt type surfactant is at least one selected from the group consisting of dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide.

Optionally, in step e, the ammonium-sodium salt comprises: treating the NaY molecular sieve by adopting an ammonium salt solution with the ammonium ion concentration of 0.1-1.0 mol/L, wherein the treatment conditions are as follows: the temperature is 50-100 ℃, and the liquid-solid weight ratio is (8-15): 1, the time is 0.5-1.5 hours; the ammonium salt is at least one selected from ammonium nitrate, ammonium sulfate, ammonium chloride and ammonium acetate.

Optionally, in step e, the hydrothermal treatment comprises: treating the NaY molecular sieve subjected to sodium reduction by ammonium exchange for 1-3 hours under the conditions of 100% of water vapor, gauge pressure of 0.1-0.2 MPa and temperature of 500-650 ℃.

Optionally, in step e, the dealuminizing and silicon supplementing method includes: pulping the NaY molecular sieve after the hydrothermal treatment to obtain a product with a liquid-solid weight ratio of (3-10): 1, adding 10-60 g (NH) of NaY molecular sieve per 100g₄)₂SiF₆Will be (NH)₄)₂SiF₆Adding the slurry, stirring for 0.5-5 hours at the temperature of 80-120 ℃, and recovering the product。

According to the technical scheme, the method comprises the steps of firstly preparing a directing agent by adopting a special treatment means, then carrying out hydrothermal crystallization on a mixture consisting of the directing agent, water, a silicon source and an aluminum source to obtain a crystallized product containing small-crystal-grain NaY, filtering out crystallization mother liquor, pulping again, assembling the small-crystal-grain NaY by using amorphous silica-alumina remained in the obtained slurry and remained on the surface of the small-crystal-grain NaY under the action of a silane coupling agent and a surfactant to obtain the NaY molecular sieve with a regular mesoporous-microporous structure stacked by the small-crystal-grain NaY, and finally carrying out ammonium sodium exchange reduction, hydrothermal treatment and post-treatment modification of dealuminization and silicon supplementation on the NaY molecular sieve with the regular mesoporous-microporous structure to obtain the modified Y molecular sieve. The method overcomes the defect that small crystal grain NaY is not easy to separate in the synthesis and use processes, retains micropores of a Y molecular sieve, simultaneously introduces mesopores, has good connectivity between the mesopores and the micropores, is favorable for macromolecular diffusion, and has high crystal retention degree, simple preparation process and easy operation.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

FIG. 1 is an XRD spectrum of a sample of the NaY molecular sieve prepared in example 1;

FIG. 2 is a small angle XRD spectrum of a sample of the NaY molecular sieve prepared in example 1;

FIG. 3 is a BET adsorption-desorption isotherm of a NaY molecular sieve sample prepared in example 1 and a comparative sample prepared in comparative example 1;

FIG. 4 is an SEM image of a sample of the NaY molecular sieve prepared in example 1;

FIG. 5 is an XRD spectrum of a comparative sample prepared in comparative example 1;

FIG. 6 is a small angle XRD spectrum of a comparative sample prepared in comparative example 1;

fig. 7 is an SEM spectrum of a comparative sample prepared in comparative example 1.

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

The first aspect of the disclosure: provides a modified Y molecular sieve with regular mesopores-micropores, which is characterized in that the framework SiO of the modified Y molecular sieve₂/Al₂O₃The molar ratio of (A) to (B) is 5.0 to 6.0, and the specific surface area of the micropores is 400 to 600m²The volume of the micropores is 0.25-0.35 cm³The mesoporous specific surface area is 30-200 m²The mesoporous volume is 0.07-0.85 cm³The mesoporous aperture is 2.0-6.0 nm, and the content of sodium oxide in the modified Y molecular sieve is not more than 0.1 wt% based on the total weight of the modified Y molecular sieve.

The modified Y molecular sieve disclosed by the invention has a regular mesopore-micropore structure, and the connectivity of mesopores and micropores is good, so that macromolecule diffusion is facilitated.

In a second aspect of the present disclosure: there is provided a process for preparing a modified Y molecular sieve according to the first aspect of the present disclosure, the process comprising:

e. and d, sequentially carrying out ammonium sodium reduction, hydrothermal treatment and dealumination and silicon supplement on the NaY molecular sieve obtained in the step d to obtain the modified Y molecular sieve.

The method comprises the steps of firstly preparing a directing agent by adopting a special treatment means, then carrying out hydrothermal crystallization on a mixture consisting of the directing agent, water, a silicon source and an aluminum source to obtain a crystallized product containing small-crystal-grain NaY, filtering out crystallization mother liquor, pulping again, assembling the small-crystal-grain NaY by using amorphous silica-alumina remained in slurry and remained on the surface of the small-crystal-grain NaY under the action of an organosilane coupling agent and a surfactant to obtain the NaY molecular sieve with a regular mesopore-micropore structure stacked by the small-crystal-grain NaY, and finally carrying out ammonium sodium reduction, hydrothermal treatment and post-treatment modification of dealuminization and silicon supplementation on the NaY molecular sieve with the regular mesopore-micropore to obtain the modified Y molecular sieve.

According to the disclosure, in the step a, the mixing of sodium metaaluminate and water glass can be carried out at a temperature of 15-60 ℃ under stirring, and the composition of the first mixture can be Na calculated by oxide and by mol₂O：A1₂O₃：SiO₂＝(6～25)：1：(6～25)。

According to the disclosure, in step a, the first mixture is subjected to dynamic aging, standing aging and water addition in sequence to obtain the second mixture. The dynamic aging may include: stirring and aging for 5-48 hours at 15-60 ℃; the standing aging may include: standing and aging for 5-48 hours at 15-60 ℃. After dynamic and aging standing and aging, water can be added under the stirring condition until the required proportion of the second mixture is reached, and the obtained second mixture is the guiding agent. The preparation of the guiding agent is different from the conventional preparation process of the NaY molecular sieve guiding agent in which a silicon source and an aluminum source are mixed in any order and are aged under a static condition after being uniformly mixed, and the guiding agent prepared by the process is adopted to carry out subsequent hydrothermal crystallization, so that a crystallized product containing small-grain NaY can be obtained more favorably.

According to the present disclosure, in step b, silicon may be incorporated according to a directing agentAnd sequentially adding the materials into a mixing tank in the order of the source, the aluminum source and the water to obtain the third mixture. The composition of the third mixture may be Na, calculated as oxides and in moles₂O：A1₂O₃：SiO₂：H₂O ═ 2 to 6: 1: (8-20): (200-400). The aluminum element in the second mixture may account for 3 to 30% of the aluminum element in the third mixture by element and by mole.

According to the present disclosure, in step b, the water may be deionized water or distilled water. The silicon source may be an inorganic silicon source commonly used for synthesizing NaY molecular sieve, for example, at least one selected from water glass, silica sol, silica gel and silica white. The aluminum source may also be conventional for synthesizing NaY molecular sieves, such as at least one selected from the group consisting of sodium metaaluminate, aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum hydroxide, and pseudoboehmite.

According to the present disclosure, in step c, the conditions of the hydrothermal crystallization may be conventional conditions for synthesizing NaY molecular sieve, such as: the temperature can be 90-100 ℃ and the time can be 15-48 hours.

According to the disclosure, slurry containing small crystal grain NaY can be obtained after hydrothermal crystallization, then crystallization mother liquor is filtered, solid obtained after hydrothermal crystallization is collected, the solid is pulped again, silane coupling agent and surfactant are added, assembly reaction can occur, and the regular mesoporous-microporous NaY molecular sieve formed by stacking small crystal grain NaY is obtained. In step d, A1₂O₃The molar ratio of the slurry to the silane coupling agent, surfactant may be 1: (0.04-10): (0.04-10). The meaning of reslurrying is well known to those skilled in the art and means that the solid from which the crystallization mother liquor is filtered is added to water and optional solvent and stirred uniformly, the amount of the added water and optional solvent can vary widely, and the disclosure is not particularly limited.

In step d, the meaning of the silane coupling agent is well known to those skilled in the art and may be of the general formula R¹Si(L¹)₃A compound of wherein L¹May be selected fromOne of methoxy, ethoxy, chlorine and methoxyethoxy, R¹May be one selected from the group consisting of a phenyl group, a C1-C22 chain alkyl group, a C1-C22 alkenyl group and a terminal substituted hydrocarbon group, and the terminal substituted hydrocarbon group may have at least one substituent selected from the group consisting of a chlorine group, an amino group, an epoxy group, a vinyl group and a methacryloxy group. Further, the silane coupling agent may be at least one selected from the group consisting of octadecyltrimethoxysilane, vinyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane and 3- (2, 3-glycidoxy) propyltrimethoxysilane.

In step d, the quaternary ammonium surfactant is well known to those skilled in the art in light of this disclosure and may be of the general formula R²N(R³)₃A compound represented by X, wherein R²May be a C8-C22 alkanyl radical, R³Can be a hydrocarbon group, and X is a halogen (e.g., Cl or Br) or a hydroxyl group. Further, the surfactant may be at least one selected from the group consisting of dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide.

According to the disclosure, after the NaY molecular sieve with a regular mesoporous-microporous structure stacked by small crystal grains NaY is obtained, the NaY molecular sieve is subjected to ammonium sodium exchange reduction, hydrothermal treatment and dealumination and silicon supplementation, so that the modified NaY molecular sieve disclosed by the disclosure can be obtained.

In step e, the ammonium crosslinked sodium is well known to those skilled in the art, and the purpose of the ammonium crosslinked sodium is to reduce the content of sodium oxide in the molecular sieve to 2.5-5.0 wt%. Specifically, the ammonium croscarmellose sodium may include: and treating the NaY molecular sieve by adopting an ammonium salt solution with the ammonium ion concentration of 0.1-1.0 mol/L. The conditions of the treatment may be: the temperature is 50-100 ℃, and the liquid-solid weight ratio is (8-15): 1 for 0.5 to 1.5 hours, and the treatment can be carried out under stirring conditions. The ammonium salt may be at least one selected from ammonium nitrate, ammonium sulfate, ammonium chloride and ammonium acetate. The ammonium-sodium reduction process can be carried out once or more times until the content of sodium oxide in the NaY molecular sieve is reduced to a target value.

The hydrothermal treatment and dealumination and silicon supplementation in step e are also well known to those skilled in the art in light of the present disclosure. Specifically, the hydrothermal treatment may include: treating the NaY molecular sieve subjected to sodium reduction by ammonium exchange for 1-3 hours under the conditions of 100% of water vapor, gauge pressure of 0.1-0.2 MPa and temperature of 500-650 ℃. The dealuminizing and silicon supplementing may include: pulping the NaY molecular sieve after the hydrothermal treatment to obtain a product with a liquid-solid weight ratio of (3-10): 1, adding 10-60 g (NH) of NaY molecular sieve per 100g₄)₂SiF₆Will be (NH)₄)₂SiF₆Adding the slurry, stirring for 0.5-5 hours at the temperature of 80-120 ℃, and recovering the product. The process of recovering the product may include filtration and drying. Through hydrothermal treatment and dealumination and silicon supplement, silicon in ammonium hexafluorosilicate is mainly supplemented to the surface of the NaY molecular sieve, crystal lattice vacancies generated by removing silicon and aluminum during hydrothermal aging are filled, the surface silicon-aluminum ratio of the NaY molecular sieve is greatly increased, the integral framework silicon-aluminum ratio is only slightly increased, and finally the obtained modified Y molecular sieve unit cell has only slight shrinkage.

By adopting the method disclosed by the invention, the micropores of the Y molecular sieve are kept and simultaneously the mesopores are introduced, and the prepared modified Y molecular sieve has good connectivity between the mesopores and the micropores, and is beneficial to macromolecular diffusion.

The present disclosure is further illustrated below by reference to examples and comparative examples, but the scope of the present disclosure is not limited thereto.

In each of the examples and comparative examples, the molecular sieve crystal structure was determined by X-ray powder diffractometry (XRD) using Holand PANalytical X' Pert PRO MPD type with Cu Ka radiation at an operating voltage of 40kV and a current of 40 mA. The calculation method of the relative crystallinity and the crystal retention degree comprises the following steps: the crystallinity of the standard sample was defined as 100%, and relative crystallinity was obtained by comparing characteristic peaks of XRD at 15.6 °, 18.6 °, 20.3 °, 23.4 °, 27.0 °, 30.7 °, 31.3 ° and 34.0 ° at 2 θ of the synthesized sample with the characteristic peaks of the standard sample. The grain size of the molecular sieve is determined by a Scanning Electron Microscope (SEM) and observed by a JSM-5610LV type scanning electron microscope.

The BET adsorption-desorption isotherms and pore distributions of the molecular sieve samples were determined by static low temperature nitrogen adsorption volumetric method (BET). The experimental apparatus used was an ASAP-2405 static nitrogen adsorption apparatus from Micromeritics, USA. The process is as follows: liquid nitrogen is contacted with the adsorbent at 77K, and the adsorbent is kept still to reach adsorption equilibrium. And calculating the amount of nitrogen adsorbed by the adsorbent according to the difference between the nitrogen gas inflow and the gas amount remained in the gas phase after adsorption. The specific surface area of micropores and the specific surface area of mesopores are calculated by using a two-parameter BET formula, and the pore size distribution is calculated by using a BJH formula.

The morphology of the molecular sieve is observed by an electron microscope. The sample is plated with a layer of gold before testing, wherein the sample is a Scanning Electron Microscope (SEM) instrument model Hitachi S-4300, the accelerating voltage is 10kV, an accessory is provided with an Energy Dispersive Spectroscopy (EDS). Observing the catalyst by using a FEI Tecnai G2F20 field emission transmission electron microscope, adopting a suspension method to prepare a sample, dispersing the catalyst sample by using absolute ethyl alcohol, uniformly shaking, dripping the mixture onto a copper net, and observing after the ethyl alcohol is completely volatilized.

Examples 1-5 are presented to illustrate NaY molecular sieves prepared according to steps a-d in the methods of the present disclosure.

Example 1

25.20g of a high alkali sodium metaaluminate solution (supplied by ChangLing division, catalyst of Zhongpetrochemical Co., Ltd., Al)₂O₃The content of Na is 40.2g/L₂O content of 255g/L and specific gravity of 1.324) was added to 32.78g of water glass (supplied by ChangLing division of catalyst, Zhongpetrochemical Co., Ltd., SiO₂The content of Na is 260.6g/L₂O content of 81.6g/L, specific gravity of 1.2655, modulus of 3.3) to obtain a molar composition of 15Na₂O:A1₂O₃:15SiO₂The first mixture of (a) was dynamically stirred and aged at room temperature for 48 hours, then left to stand and aged at 60 ℃ for 5 hours, and finally 7.5g of deionized water was added under stirring to obtain a final molar composition of 15Na₂O:A1₂O₃:15SiO₂:320H₂A second mixture of O is the directing agent.

The guiding agent (prepared in the previous step), 84.13g of water glass (same as above), and 6.71g of low alkali were added under high-speed stirring at room temperatureSodium metaaluminate solution (available from Zhongpetrochemical Co., Ltd., catalyst, ChangLing division, Al)₂O₃The content of Na is 194g/L₂O content of 286.2g/L, specific gravity of 1.413), 22.40g of aluminum sulfate (provided by ChangLing division of catalyst, Zhongpetrochemical company, Ltd., Al₂O₃88.9g/L, specific gravity 1.2829) and 7.52g of water were added in this order to a compounding pot to give a molar composition of 3Na₂O:A1₂O₃:12SiO₂:209H₂And O, and the guiding agent is added in an amount of 3% of the moles of the aluminum element in the guiding agent based on the total moles of the aluminum element in the third mixture. After being stirred evenly, the mixture is put into a stainless steel reaction kettle and is subjected to static hydrothermal crystallization for 24 hours at the temperature of 100 ℃, and then mother liquor is filtered.

Adding 100g of water and 60g of methanol into the filter cake with the mother liquor filtered out for repulping, stirring uniformly, adding 7.08g of octadecyl trimethoxy silane (98%, analytical purity, Shanghai Michelin Biochemical technology Co., Ltd.), stirring for 30min, and adding 18.20g of dodecyl trimethyl ammonium bromide (C)₁₅H₂₈NBr) (99%, analytical purity, Shanghai Michelin Biochemical technology Ltd.) as A1₂O₃The calculated molar ratio of the repulped slurry to the silane coupling agent and the surfactant is 1: 0.8: 2.4, uniformly stirring, putting into a pressure container, reacting for 42 hours at 65 ℃ under autogenous pressure, filtering, washing and drying after the reaction is finished to obtain the product with the serial number of CTC-1.

The XRD spectrum of the product is shown in figure 1, which is a typical Y molecular sieve spectrum, and the framework of the Y molecular sieve spectrum is SiO₂/Al₂O₃Has a relative crystallinity of 93.7% and a molar ratio of (2) of (5.8); the small-angle XRD spectrum is shown in figure 2, and a characteristic peak appears when 2 theta is 2 degrees, which indicates that regular mesopores exist. The BET adsorption-desorption isotherm is shown in the CTC-1 curve in FIG. 3, and the isotherm is type IV, which indicates that the molecular sieve has mesopores. The SEM representation result is shown in figure 4, and the regular mesopores are formed by the combination of small crystal grains NaY.

Example 2

25.20g of a high alkali sodium metaaluminate solution (supplied by ChangLing division, catalyst of Zhongpetrochemical Co., Ltd., Al)₂O₃The content is 40.2g/L，Na₂O content of 255g/L and specific gravity of 1.324) was added to 32.78g of water glass (supplied by ChangLing division of catalyst, Zhongpetrochemical Co., Ltd., SiO₂The content of Na is 260.6g/L₂O content of 81.6g/L, specific gravity of 1.2655, modulus of 3.3) to obtain a molar composition of 15Na₂O:A1₂O₃:15SiO₂The first mixture of (a) was dynamically stirred and aged at 60 ℃ for 5 hours, then left to stand and aged at 60 ℃ for 5 hours, and finally 7.5g of deionized water was added under stirring to give a final molar composition of 15Na₂O:A1₂O₃:15SiO₂:320H₂A second mixture of O is the directing agent.

The composition was stirred at room temperature and high speed in accordance with the guiding agent (prepared in the previous step), 84.13g of water glass (same as above), 6.71g of low alkali sodium metaaluminate solution (available from Changjingtie, a catalyst from Zhongpetrochemical Co., Ltd., Al)₂O₃The content of Na is 194g/L₂O content of 286.2g/L, specific gravity of 1.413), 22.40g of aluminum sulfate (provided by ChangLing division of catalyst, Zhongpetrochemical company, Ltd., Al₂O₃88.9g/L, specific gravity 1.2829) and 70.97g of water were added in this order to a compounding tank to obtain a mixture having a molar composition of 3Na₂O:A1₂O₃:12SiO₂:350H₂And O, and the guiding agent is added in an amount of 3% of the moles of the aluminum element in the guiding agent based on the total moles of the aluminum element in the third mixture. After being stirred evenly, the mixture is put into a stainless steel reaction kettle and is subjected to static hydrothermal crystallization for 32 hours at the temperature of 100 ℃, and then mother liquor is filtered.

Adding 100g of water and 60g of methanol into the filter cake with the mother liquor filtered out for repulping, stirring uniformly, adding 28.00g of vinyltrimethoxysilane (98%, analytical purity, Shanghai Michelin Biochemical technology Co., Ltd.), stirring for 30min, and adding 31.77g of tetradecyltrimethylammonium bromide (C)₁₇H₃₂NBr), (99%, analytical purity, Shanghai Michelin Biochemical technology Ltd.) as A1₂O₃The calculated molar ratio of the repulped slurry to the silane coupling agent and the surfactant is 1: 7.6: 3.6, uniformly stirring, then filling the mixture into a pressure containing bomb,reacting for 20 hours at the temperature of 120 ℃ under the autogenous pressure, and filtering, washing and drying after the reaction is finished to obtain the product with the serial number of CTC-2.

The XRD spectrum of the product is similar to that of figure 1, the small-angle XRD spectrum is similar to that of figure 2, and the framework SiO of the product is₂/Al₂O₃The molar ratio of (A) was 5.6, and the relative crystallinity was 91.2%. The BET adsorption-desorption isotherm is similar to CTC-1 in fig. 3. SEM characterization results were similar to fig. 4.

Example 3

82.27g of high-alkali sodium metaaluminate solution (supplied by Zhongpetrochemical Co., Ltd., catalyst, Changjingtie, Ltd., Al)₂O₃The content of Na is 40.2g/L₂O content 340g/L and specific gravity 1.297) was added to 145.68g of water glass (available from Zhongpetrochemical Co., Ltd., catalyst, ChangLing division, SiO)₂The content of Na is 260.6g/L₂O content of 81.6g/L, specific gravity of 1.2655, modulus of 3.3) to obtain a molar composition of 20Na₂O:A1₂O₃:20SiO₂The first mixture of (a) is dynamically stirred and aged at a temperature of 30 ℃ for 20 hours, then is kept stand and aged at a temperature of 40 ℃ for 15 hours, and finally 30g of deionized water is added under stirring to obtain the final molar composition of 20Na₂O:A1₂O₃:20SiO₂:380H₂A second mixture of O is the directing agent.

Under high-speed stirring at room temperature, according to the guiding agent (prepared by the previous step), 54.63g of water glass (same as above), and 8.32 of low-alkali sodium metaaluminate solution (provided by Changjingtie, a catalyst of China petrochemical company, Ltd., Al)₂O₃The content of Na is 194g/L₂O content of 286.2g/L, specific gravity of 1.413), 16.64g of aluminum sulfate (provided by ChangLing division of catalyst, Zhongpetrochemical company, Ltd., Al₂O₃88.9g/L, specific gravity 1.2829) and 23.97g of water were added in this order to a compounding tank to obtain a mixture having a molar composition of 4Na₂O:A1₂O₃:9SiO₂:220H₂And O, and the guiding agent is added in an amount of 10% of the moles of the aluminum element in the guiding agent based on the total moles of the aluminum element in the third mixture. After being stirred evenly, the mixture is put into stainless steel for reactionIn a kettle, carrying out static hydrothermal crystallization at 95 ℃ for 24 hours, and then filtering out the mother liquor.

Adding 100g of water and 80g of ethanol into the filter cake with the mother liquor filtered out for repulping, stirring uniformly, adding 11.73g of gamma-aminopropyltriethoxysilane (98%, analytical purity, Shanghai Michelin Biochemical technology Co., Ltd.), stirring for 30min, and adding 0.46g of hexadecyl trimethyl ammonium bromide (C)₁₉H₃₆NBr) (99%, analytical purity, Shanghai Michelin Biochemical technology Ltd.) as A1₂O₃The calculated molar ratio of the repulped slurry to the silane coupling agent and the surfactant is 1: 2: 0.05, uniformly stirring, then loading into a pressure vessel, reacting for 15 hours at 150 ℃ under autogenous pressure, filtering, washing and drying after the reaction is finished to obtain the product with the serial number of CTC-3.

The XRD spectrum of the product is similar to that of figure 1, the small-angle XRD spectrum is similar to that of figure 2, and the framework SiO of the product is₂/Al₂O₃The molar ratio of (A) was 5.2, and the relative crystallinity was 93.5%. The BET adsorption-desorption isotherm is similar to CTC-1 in fig. 3. SEM characterization results were similar to fig. 4.

Example 4

125.88g of high-alkali sodium metaaluminate solution (supplied by Zhongpetrochemical Co., Ltd., catalyst, Changjingtie, Ltd., Al)₂O₃The content of Na is 40.2g/L₂O content of 270g/L and specific gravity of 1.323 was added to 174.82g of water glass (supplied by Changjingtian division, a catalyst of Medium petrochemical Co., Ltd., SiO)₂The content of Na is 260.6g/L₂O content of 81.6g/L, specific gravity of 1.2655, modulus of 3.3) to obtain a molar composition of 16Na₂O:A1₂O₃:16SiO₂The first mixture of (a) was dynamically stirred and aged at 40 ℃ for 15 hours, then left to stand and aged at 15 ℃ for 20 hours, and finally 39g of deionized water was added under stirring to obtain a final molar composition of 16Na₂O:A1₂O₃:16SiO₂:290H₂A second mixture of O is the directing agent.

The mixture was stirred at room temperature and high speed with the aid of a directing agent (prepared in the preceding step), 56.45g of water glass (same above), 2.79g of low-alkali sodium metaaluminate solution (medium petrochemical fraction havingCatalyst from Limited, Yangtze division, Al₂O₃The content of Na is 194g/L₂O content of 286.2g/L, specific gravity of 1.413), 25.74g of aluminum sulfate (provided by ChangLing division of catalyst, Zhongpetrochemical Co., Ltd., Al)₂O₃88.9g/L, specific gravity 1.2829) and 24.46g of water were added in this order to a compounding tank to obtain a mixture having a molar composition of 3Na₂O:A1₂O₃:10SiO₂:250H₂And O, and the guiding agent is added in an amount of 15% of the moles of the aluminum element in the guiding agent based on the total moles of the aluminum element in the third mixture. After being stirred evenly, the mixture is put into a stainless steel reaction kettle and is subjected to static hydrothermal crystallization for 36 hours at the temperature of 95 ℃, and then mother liquor is filtered.

Adding 100g of water and 60g of methanol into the filter cake with the mother liquor filtered out for repulping, stirring uniformly, adding 19.96g of gamma-methacryloxypropyltrimethoxysilane (98%, analytical purity, Shanghai Michelin Biochemical technology Co., Ltd.), stirring for 30min, and adding 5.86g of hexadecyltrimethylammonium bromide (C)₁₉H₃₆NBr) (99%, analytical purity, Shanghai Michelin Biochemical technology Ltd.) as A1₂O₃The calculated molar ratio of the repulped slurry to the silane coupling agent and the surfactant is 1: 3.2: 0.64, uniformly stirring, then loading into a pressure container, reacting for 6 hours at 180 ℃ under autogenous pressure, filtering, washing and drying after the reaction is finished, thus obtaining the product with the serial number of CTC-4.

The XRD spectrum of the product is similar to that of figure 1, the small-angle XRD spectrum is similar to that of figure 2, and the framework SiO of the product is₂/Al₂O₃The molar ratio of (A) was 5.5, and the relative crystallinity was 93.8%. The BET adsorption-desorption isotherm is similar to CTC-1 in fig. 3. SEM characterization results were similar to fig. 4.

Example 5

167.84g of high-alkali sodium metaaluminate solution (supplied by Zhongpetrochemical Co., Ltd., catalyst, Changjingtie, Ltd., Al)₂O₃The content of Na is 40.2g/L₂O content of 270g/L and specific gravity of 1.323 was added to 233.09g of water glass (supplied by Changjingtian division, a catalyst of Medium petrochemical Co., Ltd., SiO)₂The content of Na is 260.6g/L₂O containsIn an amount of 81.6g/L, a specific gravity of 1.2655, a modulus of 3.3), 16Na was obtained as a molar composition₂O:A1₂O₃:16SiO₂The first mixture of (a) was dynamically stirred and aged at 50 ℃ for 10 hours, then left to stand and aged at 20 ℃ for 36 hours, and finally 52g of deionized water was added under stirring to obtain a final molar composition of 16Na₂O:A1₂O₃:16SiO₂:290H₂A second mixture of O is the directing agent.

The composition was stirred at room temperature and high speed in accordance with the guiding agent (prepared in the previous step), 40.79g of water glass (same as above), 0.76g of low alkali sodium metaaluminate solution (available from Changjingtie, a catalyst from Zhongpetrochemical Co., Ltd., Al)₂O₃The content of Na is 194g/L₂O content of 286.2g/L, specific gravity of 1.413), 27.92g of aluminum sulfate (provided by ChangLing division of catalyst, Zhongpetrochemical company, Ltd., Al₂O₃88.9g/L, specific gravity 1.2829) and 26.43g of water were added in this order to a compounding pot to give a molar composition of 2.7Na₂O:A1₂O₃:8.6SiO₂:250H₂And O, and the guiding agent is added in an amount of 20% of the moles of the aluminum element in the guiding agent based on the total moles of the aluminum element in the third mixture. After being stirred evenly, the mixture is put into a stainless steel reaction kettle and is subjected to static hydrothermal crystallization for 48 hours at the temperature of 90 ℃, and then mother liquor is filtered.

Adding 100g of water and 60g of methanol into the filter cake with the mother liquor filtered out for repulping, stirring uniformly, adding 0.27g of 3- (2, 3-glycidoxy) propyl trimethoxy silane (98%, analytical purity, Shanghai Michelin Biochemical technology Co., Ltd.), stirring for 30min, adding 23.30g of dodecyl trimethyl ammonium bromide (C)₁₅H₂₈NBr) and 27.53g of cetyltrimethylammonium bromide (C)₁₉H₃₆NBr) (99%, analytical purity, Shanghai Michelin Biochemical technology Ltd.) as A1₂O₃The calculated molar ratio of the repulped slurry to the silane coupling agent and the surfactant is 1: 0.05: 3, uniformly stirring, putting into a pressure container, reacting for 42 hours at 65 ℃ under autogenous pressure, filtering, washing and drying after the reaction is finished to obtain the product with the product number CTC-5。

The XRD spectrum of the product is similar to that of figure 1, the small-angle XRD spectrum is similar to that of figure 2, and the framework SiO of the product is₂/Al₂O₃The molar ratio of (2) was 5.7, and the relative crystallinity was 92.2%. The BET adsorption-desorption isotherm is similar to CTC-1 in fig. 3. SEM characterization results were similar to fig. 4.

Comparative example 1

This comparative example is used to illustrate a method in which no silane coupling agent and surfactant were added during the preparation. The sources of the raw materials were the same as in example 1. The method comprises the following specific steps:

25.20g of a high alkali sodium metaaluminate solution (supplied by ChangLing division, catalyst of Zhongpetrochemical Co., Ltd., Al)₂O₃The content of Na is 40.2g/L₂O content of 255g/L and specific gravity of 1.324) was added to 32.78g of water glass (supplied by ChangLing division of catalyst, Zhongpetrochemical Co., Ltd., SiO₂The content of Na is 260.6g/L₂O content of 81.6g/L, specific gravity of 1.2655, modulus of 3.3) to obtain a molar composition of 15Na₂O:A1₂O₃:15SiO₂The first mixture of (a) was dynamically stirred and aged at room temperature for 48 hours, then statically left at 60 ℃ for 5 hours, and finally 7.5g deionized water was added under stirring to give a final molar composition of 15Na₂O:A1₂O₃:15SiO₂:320H₂A second mixture of O is the directing agent.

The composition was stirred at room temperature and high speed in accordance with the guiding agent (prepared in the previous step), 84.13g of water glass (same as above), 6.71g of low alkali sodium metaaluminate solution (available from Changjingtie, a catalyst from Zhongpetrochemical Co., Ltd., Al)₂O₃The content of Na is 194g/L₂O content of 286.2g/L, specific gravity of 1.413), 22.40g of aluminum sulfate (provided by ChangLing division of catalyst, Zhongpetrochemical company, Ltd., Al₂O₃88.9g/L, specific gravity 1.2829) and 7.52g of water were added in this order to a compounding pot to give a molar composition of 3Na₂O:A1₂O₃:12SiO₂:209H₂A third mixture of O, and the guiding agent is added according to the mole number of the aluminum element in the guiding agent accounting for the total aluminum element mole in the third mixtureCalculated as 3% of moles. After being stirred evenly, the mixture is put into a stainless steel reaction kettle and is subjected to static hydrothermal crystallization for 24 hours at the temperature of 100 ℃, and then mother liquor is filtered.

Adding 100g of water and 60g of methanol into the filter cake with the mother liquor filtered out, pulping again, stirring uniformly, adding 7.08g of octadecyl trimethoxy silane (98%, analytical purity, Shanghai Michelin Biochemical technology Co., Ltd.) as A1₂O₃The calculated molar ratio of the repulped slurry to the silane coupling agent is 1: 7.6, stirring uniformly, putting into a pressure bomb, reacting for 42 hours at 65 ℃ under autogenous pressure, filtering, washing and drying after the reaction is finished to obtain the product with the serial number of P-1.

The XRD spectrum of the product is shown in figure 5, which is a typical Y molecular sieve spectrum with a framework of SiO₂/Al₂O₃Has a relative crystallinity of 88.7% and a molar ratio of (2) of (4.8); the small-angle XRD spectrum is shown in figure 6, and 2 theta is 2 degrees without a characteristic peak, which indicates that no regular mesopores exist. The BET adsorption-desorption isotherm is shown in the P-1 curve in FIG. 3, and the isotherm is type I, which indicates that the molecular sieve has no mesopores. The SEM characterization result is shown in FIG. 7, which shows that small crystal particles NaY are not combined into more regular mesopores.

Examples 6-10 are presented to illustrate modified Y molecular sieves obtained by subjecting NaY molecular sieves prepared in examples 1-5 to ammonium sodium reduction, hydrothermal treatment, and dealumination and silicon supplementation according to step e of the disclosed process.

Example 6

The sample CTC-1 obtained in the embodiment 1 is subjected to ammonium sodium reduction, hydrothermal treatment and dealumination and silicon supplementation to obtain the modified NaY molecular sieve with regular mesopores and micropores, and the method comprises the following specific steps:

preparing 10L of ammonium nitrate aqueous solution with the concentration of 0.5mol/L, weighing 1000 g of CTC-1 molecular sieve, dissolving in 10L of prepared ammonium nitrate aqueous solution, stirring at the rotating speed of 300rpm, stirring at the constant temperature of 90 ℃ for 1 hour, filtering the molecular sieve, and repeating the operation until Na in the molecular sieve is dissolved₂The content of O is 2.5 to 5 wt%. The dried sample was subjected to hydrothermal treatment at 500 ℃ under a condition of 100% steam and a gauge pressure of 0.1MPa for 1.5 hours. Then measuring 1L of purified water, dissolving 200 g of the sample in the purified water, rapidly heating and stirring, and keeping the temperatureRapidly adding ammonium hexafluorosilicate aqueous solution into the molecular sieve slurry at 95 ℃ and the stirring speed of 300rpm, adding 50 g of ammonium hexafluorosilicate in total, then stirring at constant temperature and constant speed for 2 hours, filtering and drying to obtain the modified Y molecular sieve, wherein the product number is NY-1, and the properties are listed in Table 1.

Example 7

The sample CTC-2 obtained in the embodiment 2 is subjected to ammonium sodium reduction, hydrothermal treatment and dealumination and silicon supplementation to obtain the modified Y molecular sieve with regular mesopores and micropores, and the method comprises the following specific steps:

preparing 10L ammonium sulfate aqueous solution with the concentration of 0.2mol/L, weighing 1000 g of CTC-2 molecular sieve, dissolving in 10L ammonium nitrate aqueous solution, stirring at 300rpm at the constant temperature of 90 ℃ for 1 hour, filtering the molecular sieve, and repeating the above operations until Na in the molecular sieve is removed₂The content of O is 2.5 to 5 wt%. The dried sample was subjected to hydrothermal treatment at 570 ℃ under a condition of 100% steam and a gauge pressure of 0.2MPa for 2.0 hours. Then measuring 1L of purified water, dissolving 300 g of the sample in the purified water, rapidly heating and stirring at the temperature of 80 ℃ and the stirring speed of 300rpm, rapidly adding an ammonium hexafluorosilicate aqueous solution into the molecular sieve slurry, adding 50 g of ammonium hexafluorosilicate in total, then stirring at a constant temperature and a constant speed for 2 hours, filtering and drying to obtain the modified Y molecular sieve, wherein the product number is NY-2, and the properties are listed in Table 1.

Example 8

Carrying out ammonium sodium reduction, hydrothermal treatment and dealumination and silicon supplementation on the sample CTC-3 obtained in the embodiment 3 to obtain the modified Y molecular sieve with regular mesopores and micropores, which comprises the following specific steps:

preparing 10L ammonium chloride aqueous solution with the concentration of 0.5mol/L, weighing 1000 g of CTC-3 molecular sieve, dissolving in 10L prepared ammonium nitrate aqueous solution, stirring at the rotation speed of 300rpm, stirring at the constant temperature of 90 ℃ for 1 hour, filtering the molecular sieve, and repeating the operation until Na in the molecular sieve is obtained₂The content of O is 2.5 to 5 wt%. The dried sample was subjected to hydrothermal treatment at 550 ℃ under a 100% steam gauge pressure of 0.2MPa for 2.5 hours. Then measuring 1L of purified water, dissolving 100g of the sample in the purified water, rapidly heating and stirring at the temperature of 95 ℃ and the stirring speed of 300rpm, and rapidly adding the mixture into the molecular sieve slurryAdding 60g ammonium hexafluorosilicate into ammonium hexafluorosilicate aqueous solution, stirring at constant temperature and constant speed for 2 hours, filtering, and drying to obtain the modified Y molecular sieve, product number NY-3, and properties are listed in Table 1.

Example 9

The sample CTC-4 obtained in the embodiment 4 is subjected to ammonium sodium reduction, hydrothermal treatment and dealumination and silicon supplementation to obtain the modified Y molecular sieve with regular mesopores and micropores, and the method comprises the following specific steps:

10L of ammonium nitrate aqueous solution with the concentration of 0.7mol/L is prepared. Weighing 1000 g of CTC-4 molecular sieve, dissolving in 10L of prepared ammonium nitrate aqueous solution, stirring at the rotation speed of 300rpm, stirring at the constant temperature of 90 ℃ for 1 hour, filtering the molecular sieve, and repeating the operation until Na in the molecular sieve is obtained₂The content of O is 2.5 to 5 wt%. The dried sample was subjected to hydrothermal treatment at 600 ℃ under a 100% steam gauge pressure of 0.1MPa for 1.0 hour. Then 1L of purified water is measured, 200 g of the sample is dissolved in the purified water, the temperature is rapidly increased and the stirring speed is 300rpm, the ammonium hexafluorosilicate aqueous solution is rapidly added into the molecular sieve slurry, 50 g of ammonium hexafluorosilicate is added in total, then the mixture is stirred at constant temperature and constant speed for 2 hours, and the modified Y molecular sieve is obtained after filtration and drying, wherein the product number is NY-4, and the properties are listed in Table 1.

Example 10

The sample CTC-5 obtained in the embodiment 5 is subjected to ammonium sodium reduction, hydrothermal treatment and dealumination and silicon supplementation to obtain the modified Y molecular sieve with regular mesopores and micropores, and the method comprises the following specific steps:

10L of ammonium nitrate aqueous solution with the concentration of 0.7mol/L is prepared. Weighing CTC-51000 g, dissolving in 10L of prepared ammonium nitrate aqueous solution, stirring at the rotation speed of 300rpm, stirring at the constant temperature of 90 ℃ for 1 hour, filtering the molecular sieve, and repeating the operation until Na in the molecular sieve is obtained₂The content of O is 2.5 to 5 wt%. The dried sample was subjected to hydrothermal treatment at 600 ℃ under a 100% steam gauge pressure of 0.1MPa for 1.0 hour. Then measuring 1L of purified water, dissolving 200 g of the sample in the purified water, rapidly heating and stirring at the temperature of 95 ℃ and the stirring speed of 300rpm, rapidly adding an ammonium hexafluorosilicate aqueous solution into the molecular sieve slurry, adding 60g of ammonium hexafluorosilicate in total, and then constantly addingStirring at a constant temperature and speed for 2 hours, filtering and drying to obtain the modified Y molecular sieve with the product number NY-5 and the properties listed in Table 1.

Comparative example 2

The sample P-1 obtained in comparative example 1 was subjected to sodium reduction by ammonium, hydrothermal treatment and dealumination and silicon supplementation in accordance with the procedure in example 6 to obtain comparative product No. DB-1, the properties of which are shown in Table 1.

TABLE 1

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims

1. A modified Y molecular sieve with regular mesopores-micropores is characterized in that the skeleton SiO of the modified Y molecular sieve₂/Al₂O₃The molar ratio of (A) to (B) is 5.0 to 6.0, and the specific surface area of the micropores is 400 to 600m²The volume of the micropores is 0.25-0.35 cm³The mesoporous specific surface area is 30-200 m²The mesoporous volume is 0.07-0.85 cm³(ii) a mesoporous pore diameter of 2.0 to 6.0nm, based on the modificationThe total weight of the Y molecular sieve is taken as a reference, and the content of sodium oxide in the modified Y molecular sieve is not more than 0.1 percent by weight.

2. A method of preparing the modified Y molecular sieve of claim 1, comprising:

b. Mixing the second mixture obtained in step a with water, a silicon source and an aluminum source to obtain a third mixture, wherein the composition of the third mixture is Na calculated by oxide and calculated by mole₂O：A1₂O₃：SiO₂：H₂O ═ 2 to 6: 1: (8-20): (200-400) the aluminum element in the second mixture accounts for 3-30% of the aluminum element in the third mixture by element and by mol;

3. The method of claim 2, wherein in step a, the dynamic aging comprises: stirring and aging for 5-48 hours at 15-60 ℃; the standing and aging comprises the following steps: standing and aging for 5-48 hours at 15-60 ℃.

4. The method according to claim 2, wherein in step b, the silicon source is at least one selected from water glass, silica sol, silica gel and silica white; the aluminum source is at least one selected from sodium metaaluminate, aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum hydroxide and pseudo-boehmite.

5. The method according to claim 2, wherein in step c, the hydrothermal crystallization conditions are as follows: the temperature is 90-100 ℃, and the time is 15-48 hours.

6. The method of claim 2, wherein in step d, A1 is used as the active ingredient₂O₃The molar ratio of the slurry to amphiphilic organosilane, surfactant calculated as 1: (0.04-10): (0.04-10).

7. The method of claim 2, wherein in step d, the silane coupling agent is of the formula R¹Si(L¹)₃A compound of formula (I), L¹Is one selected from methoxy, ethoxy, chlorine and methoxyethoxy, R¹Is one selected from phenyl, C1-C22 chain alkyl, C1-C22 alkenyl and terminal substituted alkyl, wherein the terminal substituted alkyl is at least one selected from chlorine, amino, epoxy, vinyl and methacryloxy.

8. The method according to claim 7, wherein in the step d, the silane coupling agent is at least one selected from the group consisting of octadecyltrimethoxysilane, vinyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane and 3- (2, 3-glycidoxy) propyltrimethoxysilane.

9. The method of claim 2, wherein in step d, the quaternary ammonium surfactant is of the formula R²N(R³)₃A compound represented by X, R²Is C8-C22 alkanyl radical, R³Is a hydrocarbyl group, and X is halogen or hydroxyl.

10. The method according to claim 9, wherein in step d, the quaternary ammonium salt type surfactant is at least one selected from the group consisting of dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide.

11. The method of claim 2, wherein in step e, the ammonium-crosslinked sodium reduction comprises: treating the NaY molecular sieve by adopting an ammonium salt solution with the ammonium ion concentration of 0.1-1.0 mol/L, wherein the treatment conditions are as follows: the temperature is 50-100 ℃, and the liquid-solid weight ratio is (8-15): 1, the time is 0.5-1.5 hours; the ammonium salt is at least one selected from ammonium nitrate, ammonium sulfate, ammonium chloride and ammonium acetate.

12. The method of claim 2, wherein in step e, the hydrothermal treatment comprises: treating the NaY molecular sieve subjected to sodium reduction by ammonium exchange for 1-3 hours under the conditions of 100% of water vapor, gauge pressure of 0.1-0.2 MPa and temperature of 500-650 ℃.

13. The method of claim 2, wherein in step e, the dealuminizing and silicon supplementing comprises: pulping the NaY molecular sieve after the hydrothermal treatment to obtain a product with a liquid-solid weight ratio of (3-10): 1, adding 10-60 g (NH) of NaY molecular sieve per 100g₄)₂SiF₆Will be (NH)₄)₂SiF₆Adding the slurry, stirring for 0.5-5 hours at the temperature of 80-120 ℃, and recovering the product.