CN116354359A - Pure silicon MFI structure molecular sieve and preparation method thereof - Google Patents

Pure silicon MFI structure molecular sieve and preparation method thereof Download PDF

Info

Publication number
CN116354359A
CN116354359A CN202111625585.2A CN202111625585A CN116354359A CN 116354359 A CN116354359 A CN 116354359A CN 202111625585 A CN202111625585 A CN 202111625585A CN 116354359 A CN116354359 A CN 116354359A
Authority
CN
China
Prior art keywords
chain alkyl
molecular sieve
silicon source
long
seed crystal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202111625585.2A
Other languages
Chinese (zh)
Inventor
崔岩
张淑莹
沈宜泓
郭成玉
王晓化
薄雅文
于宏悦
李梦晨
沈雨歌
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Petrochina Co Ltd
Original Assignee
Petrochina Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Petrochina Co Ltd filed Critical Petrochina Co Ltd
Priority to CN202111625585.2A priority Critical patent/CN116354359A/en
Publication of CN116354359A publication Critical patent/CN116354359A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B37/00—Compounds having molecular sieve properties but not having base-exchange properties
    • C01B37/02—Crystalline silica-polymorphs, e.g. silicalites dealuminated aluminosilicate zeolites
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/12—Surface area
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Abstract

The invention provides a pure silicon MFI structure molecular sieve and a preparation method thereof, wherein the preparation method comprises the following steps: (1) Stirring the mixed solution containing the first silicon source, the alkali source, the long-chain alkyl quaternary ammonium salt and water at 20-80 ℃ for 0.5-48 h to obtain a mixed system; the first silicon source comprises an inorganic silicon source, and the long-chain alkyl quaternary ammonium salt has long-chain alkyl, and the carbon number of the long-chain alkyl is not less than 8; (2) Adding seed crystal into the mixed system to prepare first crystallized gel; (3) And (3) carrying out crystallization reaction on the first crystallized gel under hydrothermal conditions to obtain the pure silicon MFI structure molecular sieve. The method can efficiently synthesize the pure silicon MFI structure molecular sieve, and has the advantages of simple process, low cost, environmental protection and the like.

Description

Pure silicon MFI structure molecular sieve and preparation method thereof
Technical Field
The invention relates to a pure silicon MFI structure molecular sieve and a preparation method thereof.
Background
Currently, molecular sieves with an MFI structure are widely used, for example, ZSM-5 molecular sieves with an MFI topological structure are high-silicon molecular sieves synthesized for the first time in 1972 by Mobil corporation in the United states, and have a unique pore structure including ten-membered ring straight pore channels and sinusoidal tortuous pore channels which are cross-communicated with the straight pore channels, wherein the pore sizes are respectively 0.51nm×0.55nm and 0.53nm×0.56nm, and the molecular sieves are excellent shape selective catalytic materials and have been widely used in petroleum industrial processes such as catalytic cracking, alkylation, methanol-to-olefin, aromatization and the like. The pure silicon ZSM-5 molecular sieve (silicate-1 molecular sieve) has excellent performance in the application of VOCs gas adsorption and the like due to the unique characteristics of non-acidity, hydrophobicity and the like.
At present, research and report about MFI structure molecular sieves are made, for example, patent document CN109195693a discloses a method for manufacturing a separation membrane using MFI type zeolite (pure silicalite), and the process is aimed at manufacturing a separation membrane with a dense pure silicalite separation membrane covering the surface of a porous support, which has complex process and high cost, and is not suitable for industrial preparation of pure silicalite MFI type molecular sieves.
In addition, patent document CN 103121689a discloses a preparation method of pure silicon MFI zeolite molecular sieve, inorganic alkali, silicon source, deionized water and prepared seed crystal solution are mixed and crystallized for 24-144 hours at 150-180 ℃, then crystallized product is washed, filtered, dried and baked to obtain nano-grade pure silicon MFI zeolite molecular sieve, tetrapropylammonium salt is adopted as template agent in the process, amorphous silicon spheres with bulk density of 200-500 g/L and particle size of 15-20 meshes are adopted as integral crystal-transferring silicon source, through the above process, amorphous silicon spheres are transferred into nano-grade pure silicon MFI zeolite molecular sieve with particle size of 15-20 meshes, which has higher requirement on silicon source, narrow application range, and meanwhile, the prepared product has the defects of unstable structure and the like.
In addition, patent documents CN 107335465A and CN 107335464A disclose a preparation method of a silicate-1 molecular sieve catalyst, wherein a silicon source, a noble metal source, an organic template agent and water are mixed to prepare a colloid mixture; and then carrying out hydrothermal crystallization on the colloid mixture, sequentially washing and separating the crystallized product to obtain a silicate-1 molecular sieve containing noble metal ions, and sequentially carrying out the steps of forming treatment, roasting treatment, alkaline buffer solution post-treatment of a nitrogen-containing compound and the like on the silicate-1 molecular sieve to obtain the silicate-1 molecular sieve catalyst containing noble metal ions.
In addition, patent document CN 102602959a discloses a preparation method of nano pure silicon ZSM-5 zeolite, which uses organosilicate as a silicon source, tetrapropylammonium hydroxide or a substance capable of generating tetrapropylammonium hydroxide as a template agent, and introduces acid, alkali or fluoride salt as a hydrolysis agent, the three are mixed with water to prepare silica gel, and then crystallized for 1-7 days at 100-190 ℃, and then the crystallized product is calcined to prepare nano pure silicon ZSM-5 zeolite with grain smaller than 100 nm.
In addition, patent document CN108975352a discloses a preparation method of nano pure silicon ZSM-5 zeolite, which comprises mixing a silicon source, a template agent and water to prepare a templated hydrogel, adding a mineralizer to prepare a semi-solid gel, purifying the semi-solid gel at 110-170 ℃ for 24-96 hours to prepare the nano pure silicon ZSM-5 zeolite, wherein one or more of tetramethyl ammonium hydroxide, tetraethyl ammonium hydroxide and tetrapropyl ammonium hydroxide solution is adopted as the template agent in the process, one or more of sodium fluoride, potassium fluoride and ammonium fluoride are required to be introduced as the mineralizer, so that larger pressure is caused to production equipment and subsequent pollutant treatment, and the defects of complex preparation system, high cost, environmental protection, unstable structure of the prepared nano pure silicon ZSM-5 zeolite and the like exist.
Although there are reports about pure silicon MFI structure molecular sieves and their preparation processes, the preparation process of pure silicon MFI structure molecular sieves still needs to be optimized, and especially in terms of simplifying the preparation process, reducing the cost, reducing the pollution, improving the quality of pure silicon MFI structure molecular sieves, etc., the preparation process is still an important subject faced by those skilled in the art. In addition, the existing preparation process of the pure silicon MFI structure molecular sieve is mainly aimed at preparing the pure silicon MFI structure molecular sieve of the nano-scale particles, researches on the pure silicon MFI structure molecular sieve of the micro-scale particles and the preparation process thereof are less, and development of the novel pure silicon MFI structure molecular sieve and the preparation process thereof has important significance on the aspects of application, research and the like of the pure silicon MFI structure molecular sieve.
Disclosure of Invention
The invention provides a pure silicon MFI structure molecular sieve and a preparation method thereof, which have the advantages of simple process, low cost, environmental protection, high crystallinity of the pure silicon MFI structure molecular sieve and the like, and can effectively overcome the defects existing in the prior art.
In one aspect of the present invention, a method for preparing a pure silicon MFI structure molecular sieve is provided, comprising: (1) Stirring the mixed solution containing the first silicon source, the alkali source, the long-chain alkyl quaternary ammonium salt and water at 20-80 ℃ for 0.5-48 h to obtain a mixed system; the first silicon source comprises an inorganic silicon source, the long-chain alkyl quaternary ammonium salt is provided with long-chain alkyl, and the carbon number of the long-chain alkyl is not less than 8; (2) Adding seed crystal into the mixed system to prepare first crystallization gel; (3) And (3) carrying out crystallization reaction on the first crystallization gel under a hydrothermal condition to obtain the pure silicon MFI structure molecular sieve.
According to one embodiment of the invention, the first silicon source is SiO 2 Calculated by metal oxide, long-chain alkyl quaternary ammonium salt calculated by quaternary ammonium cation, seed crystal calculated by SiO 2 The mole ratio of the seed crystal to the first silicon source is 0.002-0.250: 1, the mole ratio of the alkali source to the first silicon source is 0.04-0.50: 1, the molar ratio of the long-chain alkyl quaternary ammonium salt to the first silicon source is 0.003-0.125: 1, water and the firstThe mole ratio of the silicon source is 15-120: 1.
according to an embodiment of the present invention, the long-chain alkyl quaternary ammonium salt has 1 long-chain alkyl group and 3 short-chain alkyl groups, and the number of carbons of the short-chain alkyl groups is 1 to 6.
According to an embodiment of the present invention, the long-chain alkyl group has 8 to 22 carbon atoms.
According to an embodiment of the present invention, the long-chain alkyl quaternary ammonium salt includes at least one of cetyltrimethylammonium bromide, cetyltrimethylammonium hydroxide, cetyltrimethylammonium chloride, cetyltrimethylammonium bisulfate, cetyltriethylammonium chloride, dodecyltrimethylammonium bromide, and dodecyltrimethylammonium hydroxide.
According to an embodiment of the present invention, the inorganic silicon source includes at least one of silica sol, solid silica gel, white carbon black, and water glass; and/or the alkali source comprises sodium hydroxide and/or potassium hydroxide.
According to an embodiment of the present invention, in the step (2), after adding seed crystals to the mixed system, stirring is performed at 20 ℃ to 80 ℃ for 0.5h to 48h, so as to obtain the first crystallized gel.
According to one embodiment of the invention, the crystallization reaction temperature is 120-190 ℃ and/or the crystallization reaction time is 12-120 h.
According to an embodiment of the present invention, in step (2), a seed crystal liquid is added to the mixed system to realize adding seed crystal thereto, and the preparation process of the seed crystal liquid includes: mixing a second silicon source, a template agent and water to prepare second crystal gel; the second silicon source comprises at least one of ethyl silicate, silica sol, solid silica gel, white carbon black and water glass, and the template agent comprises tetrapropylammonium salt and/or tetraethylammonium salt; second silicon source is SiO 2 The molar ratio of the template agent to the second silicon source is 0.09-0.5: 1, the mole ratio of water to the second silicon source is 10-100: 1, a step of; crystallizing the second crystallized gel at 70-130 ℃ for 12-72 h to obtain the seed crystal liquid.
In another aspect of the invention, a pure silicon MFI structure molecular sieve is provided, and the molecular sieve is prepared according to the preparation method.
According to the invention, long-chain alkyl quaternary ammonium salt is introduced as a template agent in the process of preparing the pure silicon MFI structure molecular sieve by adopting an inorganic silicon source for the first time, the pure silicon MFI structure molecular sieve can be directly synthesized in one step through the processes of the steps (1) to (3), the preparation process is simple, the inorganic silicon source and other materials are adopted, and meanwhile, a fluorine-containing mineralizer and an acid, alkali or fluoride salt and other hydrolyzer are not required to be introduced, so that the method has the advantages of low cost, environmental protection, simplicity in operation and the like. In addition, the invention can prepare high-quality pure silicon MFI structure molecular sieve, and research shows that the pure silicon MFI structure molecular sieve has high crystallinity, is a pure phase MFI structure molecular sieve, is in micron-sized particles, has good structural stability, is not easy to generate aggregation and other phenomena, is beneficial to use, can prepare pure silicon ZSM-5 molecular sieve (silicate-1 molecular sieve) with high crystallinity, pure phase and micron-sized particles, has wide application range and has important significance for practical industrialized application.
Drawings
FIG. 1 is an XRD spectrum of seed A used in the examples of the present invention;
FIG. 2 is an SEM image of seed crystal A used in the example of the present invention;
FIG. 3 is an XRD spectrum of the pure silicon MFI structure molecular sieve synthesized in example 1;
FIG. 4 is an SEM image of the pure silicon MFI structure molecular sieve synthesized in example 1;
FIG. 5 is an XRD spectrum of the pure silicon MFI structure molecular sieve synthesized in example 3;
FIG. 6 is an SEM image of a pure silicon MFI structure molecular sieve synthesized in example 3;
FIG. 7 is an XRD pattern of seed B used in the examples of the present invention;
FIG. 8 is an SEM image of seed B used in the examples of the present invention;
FIG. 9 is an XRD spectrum of the pure silicon MFI structure molecular sieve synthesized in example 5;
FIG. 10 is an SEM image of a pure silicon MFI structure molecular sieve synthesized in example 5;
FIG. 11 is an XRD spectrum of the molecular sieve product synthesized in comparative example 1;
fig. 12 is an SEM image of the molecular sieve product synthesized in comparative example 1.
Detailed Description
The present invention will be described in further detail below for the purpose of better understanding of the aspects of the present invention by those skilled in the art. The following detailed description is merely illustrative of the principles and features of the present invention, and examples are set forth for the purpose of illustration only and are not intended to limit the scope of the invention. All other embodiments, which can be made by those skilled in the art based on the examples of the invention without making any inventive effort, are intended to be within the scope of the invention. In the description of the present invention, the terms "first", "second", etc. are used for descriptive purposes only, for example to distinguish between components, in order to more clearly illustrate/explain the technical solution, but are not to be understood as indicating or implying a quantity of technical features indicated or an order of substantial significance, etc.
The preparation method of the pure silicon MFI structure molecular sieve provided by the invention comprises the following steps: (1) Stirring the mixed solution containing the first silicon source, the alkali source, the long-chain alkyl quaternary ammonium salt and water at 20-80 ℃ for 0.5-48 h to obtain a mixed system; the first silicon source comprises an inorganic silicon source, and the long-chain alkyl quaternary ammonium salt has long-chain alkyl, and the carbon number of the long-chain alkyl is not less than 8; (2) Adding seed crystal into the mixed system to prepare first crystallized gel; (3) And (3) carrying out crystallization reaction on the first crystallized gel under hydrothermal conditions to obtain the pure silicon MFI structure molecular sieve.
The inventor considers that, through the research and analysis, the inorganic silicon source can be depolymerized under the alkaline condition to form small aggregated micelles, and meanwhile, the small aggregated micelles are compounded with components such as long-chain alkyl quaternary ammonium salt to prepare a proper mixed system (generally in a gel state), then seed crystals are added into the mixed system to prepare crystallized gel, and then crystallization reaction is carried out under the hydrothermal condition, wherein the seed crystals and the long-chain alkyl quaternary ammonium salt can cooperatively assist crystallization, so that the pure silicon MFI structure molecular sieve can be synthesized with high efficiency.
According to the research of the invention, the pure silicon MFI structure molecular sieve prepared by the preparation processGenerally has the following characteristics: the crystallinity is high, the molecular sieve is in micron-sized particles, has a microporous structure, and the total specific surface area of the pure silicon MFI structure molecular sieve is 330m according to the analysis result of the total pore specific surface area and the porosity 2 /g～350m 2 /g, e.g. 330m 2 /g、332m 2 /g、335m 2 /g、338m 2 /g、340m 2 /g、342m 2 /g、345m 2 /g、348m 2 /g、350m 2 In the composition of/g or any two of them, the micropore specific surface area is 190m 2 /g～230m 2 /g, e.g. 190m 2 /g、191m 2 /g、195m 2 /g、198m 2 /g、200m 2 /g、215m 2 /g、220m 2 /g、225m 2 /g、230m 2 /g or any two thereof.
In some embodiments, the pure silicon MFI structure molecular sieve may specifically include a pure silicon ZSM-5 molecular sieve (silicate-1 molecular sieve), and the high quality pure silicon ZSM-5 molecular sieve having the above characteristics can be obtained through the above preparation process.
In the preparation process, the dosages of all the components can generally meet the following conditions: first silicon source is SiO 2 Calculated as metal oxide (i.e., as M when the alkali source is an alkali metal hydroxide (MOH)) 2 O), long-chain alkyl quaternary ammonium salt is cationic with quaternary ammonium (A) + ) Metering the seed crystal by SiO 2 The mole ratio of the seed crystal to the first silicon source is 0.002-0.250: 1, for example, 0.002:1, 0.005:1, 0.008:1, 0.01:1, 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1 or any two ratio thereof, the molar ratio of the alkali source to the first silicon source is from 0.04 to 0.50:1, for example, 0.04:1, 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, or any two ratios therein, the molar ratio of the long chain alkyl quaternary ammonium salt to the first silicon source being from 0.003 to 0.125:1, for example, 0.003:1, 0.005:1, 0.008:1, 0.01:1, 0.05:1, 0.08:1, 0.1:1, 0.125:1 or any two ratio therein, the molar ratio of water to the first silicon source being from 15 to 120:1, e.g., 15:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, 110:1120:1 or any two ratios thereof.
It is generally considered that the pure silicon MFI structure molecular sieve has great difficulty in constructing the crystal structure, a large amount of organic template agents such as tetramethyl ammonium salt and the like and high-activity organic silicon sources such as ethyl silicate and the like are needed, and when cheap inorganic silicon is adopted as a silicon source, the crystallization difficulty is high because the activity of the inorganic silicon source is low, and auxiliary crystallization substances such as high-content fluorine-containing mineralizer and the like are often needed to be added into a crystallization system, and meanwhile, more template agents (usually short carbon chain quaternary ammonium salt such as tetrapropyl ammonium) are needed, so that better effect is achieved; on the other hand, the silicon-aluminum ratio of the molecular sieve synthesized by the current mode of adding seed crystal to induce the synthesis of the MFI structure molecular sieve is limited (generally not more than 200), and for synthesizing the molecular sieve with high silicon content, especially the pure silicon MFI structure molecular sieve, the addition amount of the template agent, the seed crystal and other auxiliary crystallization substances is often required to be increased. Therefore, the problems of high preparation cost, complex treatment process, serious environmental pollution and the like commonly exist in the synthesis process of the pure silicon MIF structure molecular sieve at the present stage. In the invention, the cheap and easily obtained inorganic silicon source is used as a synthesis raw material, the long-chain alkyl quaternary ammonium salt is used as a template agent, the depolymerization pretreatment of the step (1) is carried out, and then the step (2) and the step (3) are sequentially carried out, so that the pure silicon MFI structure molecular sieve can be efficiently synthesized, the use amount of substances such as seed crystals, the template agent and the like can be reduced, the cost is low, the treatment process is simple, the pollutant emission in the post-treatment process can be reduced, the environment is more friendly, the quality such as the crystallinity and the structural stability of the synthesized pure silicon MFI structure molecular sieve can be improved, and the high-value application of the inorganic silicon source can be realized.
Specifically, the long-chain alkyl group in the long-chain alkyl quaternary ammonium salt is bonded to the N element of a quaternary ammonium cation (A) + ) The structure is schematically as follows:
Figure BDA0003438719820000071
wherein R is 1 、R 2 、R 3 、R 4 At least one of which is carbon numberLong chain alkyl of not less than 8.
In some preferred embodiments, the long chain alkyl quaternary ammonium salt has 1 long chain alkyl group and 3 short chain alkyl groups, the number of carbons of the short chain alkyl groups being 1 to 6, the 3 short chain alkyl groups also being attached to the N element of the quaternary ammonium cation, i.e., R as described above 1 、R 2 、R 3 、R 4 One of them is a long-chain alkyl group having not less than 8 carbon atoms, and the other three are short-chain alkyl groups having 1 to 6 carbon atoms.
The above-mentioned short chain alkyl groups may include short chain alkyl groups having at least one of carbon numbers 1, 2, 3, 4, 5, 6, for example, R 1 Is long chain alkyl, R 2 、R 3 、R 4 Is a short chain alkyl group, R 2 Can be 1, 2, 3, 4, 5 or 6, R 3 Can be 1, 2, 3, 4, 5 or 6, R 4 Can be 1, 2, 3, 4, 5 or 6, R 2 、R 3 、R 4 The number of carbons in (c) may be the same or different.
Further, the above-mentioned short chain alkyl group may be a straight chain alkyl group having no branching, may be an isomeric alkyl group having branching, and preferably includes a straight chain alkyl group having no branching, more preferably the above-mentioned 3 short chain alkyl groups are all straight chain alkyl groups having no branching, and particularly preferably R 2 、R 3 、R 4 At least one of them is a straight-chain alkyl group having no branching, and R is further preferable 2 、R 3 、R 4 At least two of (a) are straight-chain alkyl groups having no branching, and R is more preferable 2 、R 3 、R 4 Are straight-chain alkyl groups with no branching.
In addition, the long-chain alkyl can be straight-chain alkyl without a branched chain or can be isomerised alkyl with a branched chain, and in contrast, when the long-chain alkyl is straight-chain alkyl without a branched chain, the preparation efficiency and the quality of the prepared pure silicon MFI structure molecular sieve are further improved.
In some embodiments, the long chain alkyl group in the long chain alkyl quaternary ammonium salt described above has a carbon number of 8 to 22, for example, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 or a range consisting of any two thereof, and it is generally preferred that the long chain alkyl group comprises a dodecyl group (i.e., the carbon number of the long chain alkyl group is 12) and/or a hexadecyl group (i.e., the carbon number of the long chain alkyl group is 16).
In general, the long-chain alkyl quaternary ammonium salt may include at least one of ammonium halide having a long-chain alkyl group, ammonium hydroxide having a long-chain alkyl group, ammonium bisulfate having a long-chain alkyl group, and the ammonium halide may include, for example, ammonium chloride and/or ammonium bromide. For example, in some preferred embodiments, the long chain alkyl quaternary ammonium salt described above includes at least one of cetyltrimethylammonium bromide, cetyltrimethylammonium hydroxide, cetyltrimethylammonium chloride, cetyltrimethylammonium bisulfate, cetyltriethylammonium chloride, dodecyltrimethylammonium bromide, dodecyltrimethylammonium hydroxide.
In some embodiments, the inorganic silicon source may include at least one of silica sol, solid silica gel, white carbon, water glass. In addition, the alkali source may include an alkali metal hydroxide having the structural formula MOH, M is an alkali metal, and generally preferably includes sodium hydroxide (NaOH) and/or potassium hydroxide (KOH). In the present invention, the water may include deionized water, but is not limited thereto.
Illustratively, in step (1), the stirring temperature may be in the range of 20 ℃, 30 ℃, 40 ℃, 50 ℃, 60 ℃,70 ℃, 80 ℃ or any two thereof, generally preferably 20 ℃ to 60 ℃; the stirring time may be in the range of 0.5h, 1h, 5h, 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 48h or any two thereof.
In some embodiments, in step (2), after adding seed crystals to the mixed system, stirring at 20-80 ℃ for 0.5-48 hours to obtain the first crystallized gel. For example, in step (2), the stirring temperature may be in the range of 20 ℃, 30 ℃, 40 ℃, 50 ℃, 60 ℃,70 ℃, 80 ℃ or any two thereof, generally preferably 20 ℃ to 60 ℃; the stirring time may be in the range of 0.5h, 1h, 5h, 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 48h or any two thereof.
In the preparation process, the seed crystal is a pure silicon molecular sieve with an MFI topological structure, and the seed crystal can be purchased or self-made commercially. In some embodiments, in step (2), a seed solution may be added to the mixed system to achieve the addition of seed thereto, and the preparation process of the seed solution includes: mixing a second silicon source, a template agent and water to prepare second crystal gel; crystallizing the second crystallized gel at 70-130 deg.c for 12-72 hr to obtain seed crystal liquid. In the specific implementation, after the second silicon source, the template agent and water are mixed, the mixture can be stirred uniformly (generally can be stirred for 3 to 5 hours) at the temperature of 20 to 70 ℃ to obtain second crystallized gel, and then the second crystallized gel is transferred into a high-pressure reaction kettle for crystallization.
Wherein the second silicon source is SiO 2 The molar ratio of the template agent to the second silicon source is 0.09-0.5: 1, e.g., 0.09:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, or any two of these, the molar ratio of water to the second silicon source is from 10 to 100:1, e.g., 10:1, 20:1, 40:1, 60:1, 80:1, 100:1, or any two of these; the second silicon source may comprise at least one of ethyl silicate, silica sol, solid silica gel, white carbon, water glass, the templating agent comprises tetrapropylammonium salts and/or tetraethylammonium salts, for example comprising tetrapropylammonium hydroxide and/or tetrapropylammonium halides, for example comprising tetraethylammonium hydroxide and/or tetraethylammonium halides, tetrapropylammonium halides, for example comprising tetrapropylammonium bromide and/or tetrapropylammonium chloride, tetraethylammonium halides, for example comprising tetraethylammonium bromide and/or tetraethylammonium chloride, and in some embodiments, the templating agent comprises at least one of tetrapropylammonium hydroxide, tetrapropylammonium bromide, tetrapropylammonium chloride, tetraethylammonium hydroxide, tetraethylammonium bromide.
Further, in the step (3), the crystallization reaction may be carried out at a temperature ranging from 120℃to 190℃such as 120℃130℃140℃150℃160℃170℃180℃185℃190℃or any two thereof, and generally preferably 140℃to 185 ℃; the crystallization reaction time is in the range of 12h to 120h, for example, 12h, 20h, 24h, 30h, 40h, 50h, 60h, 70h, 72h, 80h, 90h, 100h, 110h, 120h or any two thereof, and generally preferably 24h to 72h. In particular, the crystallization reaction in step (3) may be carried out in a high-pressure reactor.
In some embodiments, the above preparation process further comprises: after the crystallization reaction is finished, roasting the obtained crystallization product to obtain the pure silicon MFI structure molecular sieve; wherein the temperature of the calcination treatment may be 540 to 600 ℃ for at least 4 hours. In specific implementation, the crystallized product can be subjected to washing, filtering and drying in sequence and then subjected to roasting treatment.
The pure silicon MFI structure molecular sieve provided by the invention is prepared according to the preparation method, and researches show that the pure silicon MFI structure molecular sieve generally has the following characteristics: the crystallinity is high, the molecular sieve is in micron-sized particles, has a microporous structure, and the total specific surface area of the pure silicon MFI structure molecular sieve is 330m according to the analysis result of the total pore specific surface area and the porosity 2 /g～350m 2 /g, e.g. 330m 2 /g、332m 2 /g、335m 2 /g、338m 2 /g、340m 2 /g、342m 2 /g、345m 2 /g、348m 2 /g、350m 2 In the composition of/g or any two of them, the micropore specific surface area is 190m 2 /g～230m 2 /g, e.g. 190m 2 /g、191m 2 /g、195m 2 /g、198m 2 /g、200m 2 /g、215m 2 /g、220m 2 /g、225m 2 /g、230m 2 /g or any two thereof. In some embodiments, the pure silicon MFI structure molecular sieve may specifically include a ZSM-5 molecular sieve (silicate-1 molecular sieve).
For the purpose of promoting an understanding of the principles of the invention, reference will now be made in detail to specific examples, some but not all of which are illustrated in the accompanying drawings. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the following examples and comparative examples, the purity/concentration of the materials used are shown in Table 1:
TABLE 1
Figure BDA0003438719820000101
In the following examples and comparative examples, seed liquid A and seed liquid B were used, respectively, according to the following procedures:
seed crystal 1: mixing 60.0g of tetrapropylammonium hydroxide solution and 80.0g of water, uniformly stirring, slowly adding 61.5g of tetraethoxysilane, stirring at normal temperature for 3 hours, transferring the solution into a high-pressure reaction kettle after the solution is clarified, crystallizing at 110 ℃ for 48 hours, and obtaining milky seed crystal liquid after crystallization is finished; 604.5g of water (diluted to 1/4 of the original volume) was added thereto, and stirred uniformly to obtain a diluted seed crystal liquid, which was designated as seed crystal liquid A;
taking a proper amount of seed crystal liquid A sample, washing, centrifugally filtering and drying the sample in sequence, and then carrying out X-ray diffraction (XRD) analysis and electron microscope Scanning (SEM) analysis on the obtained dried product (seed crystal A) to obtain an XRD spectrogram (see figure 1) and an SEM image (see figure 2) respectively, wherein the seed crystal has typical MFI structural characteristic peaks, and the seed crystal is in a uniform nano-grain morphology as seen in figure 2.
Seed crystal 2: mixing 17.5g of tetrapropylammonium bromide and 125.5g of water, uniformly stirring, slowly adding 55.0g of silica sol, stirring at 70 ℃ for 5 hours, transferring to a high-pressure reaction kettle, crystallizing at 100 ℃ for 36 hours, and obtaining milky seed crystal liquid after crystallization is finished; 792.0g of ethanol (diluted to 1/5 of the original volume) was added thereto, and stirred well to obtain a diluted seed crystal liquid, which was designated as seed crystal liquid B.
Taking a proper amount of seed crystal liquid B sample, washing, centrifugally filtering and drying the sample in sequence, and carrying out XRD analysis and SEM analysis on the obtained dried product (seed crystal B) to obtain an XRD spectrogram (see figure 7) and an SEM image (see figure 8) respectively, wherein the seed crystal has typical MFI structural characteristic peaks, and the seed crystal is in a uniform nanocrystalline morphology as seen in figure 8.
1. Examples 1 to 8
Example 1
1.1g of sodium hydroxide and 6.0g of cetyltrimethylammonium bromide are dissolved in 100g of water, 50.0g of silica sol is slowly added, and the mixture is stirred for 2 hours at 50 ℃ to obtain a mixed system; slowly adding 5.0g of seed crystal liquid A into the mixed system, and stirring for 3 hours at 50 ℃ to obtain crystallized gel; transferring the crystallized gel into a high-pressure reaction kettle, and crystallizing for 48 hours at 170 ℃ to obtain a crystallized product; washing, filtering, drying and roasting the crystallized product at about 570 ℃ in sequence to obtain the pure silicon MFI structure molecular sieve product.
Example 2
1.5g of sodium hydroxide and 3.5g of cetyltrimethylammonium bromide are dissolved in 100g of water, 50.0g of silica sol is slowly added, and the mixture is stirred for 3 hours at room temperature to obtain a mixed system; slowly adding 8.5g of seed crystal liquid A into the mixed system, and stirring for 5 hours at room temperature to obtain crystallized gel; transferring the crystallized gel into a high-pressure reaction kettle, and crystallizing for 48 hours at 170 ℃ to obtain a crystallized product; washing, filtering, drying and roasting the crystallized product at about 570 ℃ in sequence to obtain the pure silicon MFI structure molecular sieve product.
Example 3
2.1g of sodium hydroxide and 1.0g of cetyltrimethylammonium bromide are dissolved in 100g of water, 50.0g of silica sol is slowly added, and the mixture is stirred for 2 hours at 50 ℃ to obtain a mixed system; slowly adding 12.5g of seed crystal liquid A into the mixture, and stirring the mixture for 3 hours at 50 ℃ to obtain crystallized gel; transferring the crystallized gel into a high-pressure reaction kettle, and crystallizing for 36 hours at 175 ℃ to obtain a crystallized product; washing, filtering, drying and roasting the crystallized product at about 570 ℃ in sequence to obtain the pure silicon MFI structure molecular sieve product.
Example 4
2.5g of sodium hydroxide and 6.0g of cetyltrimethylammonium bromide are dissolved in 130g of water, 21.0g of solid silica gel is slowly added, and the mixture is stirred for 2 hours at 50 ℃ to obtain a mixed system; slowly adding 5.0g of seed crystal liquid A into the mixed system, and stirring for 3 hours at 50 ℃ to obtain crystallized gel; transferring the crystallized gel into a high-pressure reaction kettle, and crystallizing for 48 hours at 170 ℃ to obtain a crystallized product; washing, filtering, drying and roasting the crystallized product at about 570 ℃ in sequence to obtain the pure silicon MFI structure molecular sieve product.
Example 5
1.1g of sodium hydroxide and 48.5g of cetyltrimethylammonium hydroxide solution are dissolved in 56.4g of water, 50.0g of silica sol is slowly added, and the mixture is stirred for 2 hours at 50 ℃ to obtain a mixed system; slowly adding 5.0g of seed crystal liquid B into the mixed system, and stirring for 3 hours at 50 ℃ to obtain crystallized gel; transferring the crystallized gel into a high-pressure reaction kettle, and crystallizing for 48 hours at 170 ℃ to obtain a crystallized product; washing, filtering, drying and roasting the crystallized product at about 570 ℃ in sequence to obtain the pure silicon MFI structure molecular sieve product.
Example 6
2.5g of sodium hydroxide and 33.5g of cetyltrimethylammonium hydroxide solution are dissolved in 120.0g of water, 50.0g of silica sol is slowly added, and the mixture is stirred for 2 hours at 30 ℃ to obtain a mixed system; slowly adding 20.5g of seed crystal liquid B into the mixture, and stirring the mixture for 5 hours at the temperature of 30 ℃ to obtain crystallized gel; transferring the crystallized gel into a high-pressure reaction kettle, and crystallizing at 170 ℃ for 96 hours to obtain a crystallized product; washing, filtering, drying and roasting the crystallized product at about 570 ℃ in sequence to obtain the pure silicon MFI structure molecular sieve product.
Example 7
2.1g of sodium hydroxide and 87.5g of hexadecyl trimethyl ammonium hydroxide solution are dissolved in 101.3g of water, 21.5g of white carbon black is slowly added, and the mixture is stirred for 2 hours at 50 ℃ to obtain a mixed system; slowly adding 20.5g of seed crystal liquid B into the mixed system, and stirring for 5 hours at 50 ℃ to obtain crystallized gel; transferring the crystallized gel into a high-pressure reaction kettle, and crystallizing for 72 hours at 160 ℃ to obtain a crystallized product; washing, filtering, drying and roasting the crystallized product at about 570 ℃ in sequence to obtain the pure silicon MFI structure molecular sieve product.
Example 8
1.1g of sodium hydroxide and 6.0g of cetyltrimethylammonium bromide are dissolved in 100g of water, 50.0g of silica sol is slowly added, and the mixture is stirred for 2 hours at 50 ℃ to obtain a mixed system; slowly adding 4.8g of seed crystal liquid into the mixed system, and stirring for 3 hours at 50 ℃ to obtain crystallized gel; transferring the crystallized gel into a high-pressure reaction kettle, and crystallizing for 48 hours at 170 ℃ to obtain a crystallized product; washing, filtering, drying and roasting the crystallized product at about 570 ℃ in sequence to obtain the pure silicon MFI structure molecular sieve product.
XRD, SEM, full pore specific surface and porosity analysis are respectively carried out on the pure silicon MFI structure molecular sieve products prepared in examples 1-8, and the results show that: (1) According to XRD analysis results, the products have typical MFI structure characteristic peaks, have high crystallinity, are pure-phase MFI structure molecular sieves, and can be seen according to peak shapes (peak positions, peak intensities and the like), and are silicate-1 molecular sieves; (2) According to the SEM analysis result, the products are all in micron-sized particles; (3) According to the analysis result of the whole pore specific surface and the porosity, the products all have micropore structures, and the total specific surface area is 330m 2 /g～350m 2 Between/g, wherein the micropore specific surface area is 190m 2 /g～230m 2 Between/g.
The structure of the obtained pure silicon MFI structure molecular sieve product is described in more detail by taking example 1, example 3 and example 5 as examples respectively:
(1) The pure silicon MFI structure molecular sieve product prepared in example 1 is characterized as follows: XRD patterns are shown in FIG. 3, SEM patterns are shown in FIG. 4 (it can be seen from FIG. 4 that it has a micron-sized spindle shape), and the total specific surface area is 349.71m 2 Per g, wherein the micropore specific surface area is 215.02m 2 /g；
(2) The characteristics of the pure silicon MFI structure molecular sieve product prepared in example 3 are as follows: XRD patterns are shown in FIG. 5, SEM patterns are shown in FIG. 6 (it can be seen from FIG. 6 that the particles have a morphology of microparticles built up from nanocrystals), and the total specific surface area is 342.32m 2 Per g, wherein the micropore specific surface area is 191.92m 2 /g；
(3) The characteristics of the pure silicon MFI structure molecular sieve product prepared in example 5 are as follows: XRD patterns are shown in FIG. 9, SEM patterns are shown in FIG. 10 (which shows an irregular micron-sized morphology from FIG. 10), and the total specific surface area is 332.68m 2 Per g, wherein the micropore specific surface area is 229.37m 2 /g。
2. Comparative examples 1 to 4
Comparative example 1
Mixing 62.5g of tetrapropylammonium hydroxide solution and 50.0g of water, uniformly stirring, slowly adding 62.5g of tetraethoxysilane, stirring for 5 hours at normal temperature, transferring to a high-pressure reaction kettle after the solution is clarified, and crystallizing for 48 hours at 160 ℃ to obtain a crystallized product; washing, filtering, drying and roasting the crystallized product at about 570 ℃ in sequence to obtain a molecular sieve product;
the XRD spectrum of the molecular sieve product is shown in figure 11, and the molecular sieve product is seen to have typical MFI structure characteristic peaks;
in addition, SEM images of the molecular sieve products are shown in fig. 12, and it can be seen that the molecular sieve products are in the shape of hundred-nanometer hexagonal prisms;
in addition, the molecular sieve product is subjected to full pore specific surface and porosity analysis to determine that the total specific surface area is 329.15m 2 /g, wherein the micropore specific surface area is 257.37m 2 /g；
As can be seen from examples 1 to 8 and comparative example 1, in comparative example 1, under the condition of using organosilicon and tetrapropylammonium templates, pure-phase pure-silicon MFI structure molecular sieves with higher crystallinity can be synthesized, but the cost of the used synthetic raw materials is higher, the application economy of the molecular sieves and the preparation process thereof is affected, while in examples 1 to 8, inorganic silicon sources are used as the synthetic raw materials, and long-chain alkyl quaternary ammonium salts are used as templates, so that the cost is lower and the economic benefit is better; in addition, the molecular sieve products prepared in examples 1 to 8 are also different from comparative example 1, and the molecular sieve products prepared in examples 1 to 8 are in the form of micron-sized particles, have better structural stability, and have significant differences in specific surface areas.
Comparative example 2
Mixing 62.5g of tetrapropylammonium hydroxide solution and 23.7g of water, uniformly stirring, slowly adding 43.8g of silica sol, stirring for 5 hours at normal temperature, transferring into a high-pressure reaction kettle, and crystallizing for 48 hours at 160 ℃ to obtain a crystallized product; washing, filtering, drying and roasting the crystallized product at about 570 ℃ in sequence to obtain a molecular sieve product;
XRD analysis shows that the molecular sieve product has typical MFI structure characteristic peak, but the characteristic peak intensity is low, and the relative crystallinity of the product is low; thus, as can be seen from examples 1 to 8 and comparative example 2, when an inorganic silicon source is used as a raw material for synthesizing a molecular sieve, it is difficult to synthesize a pure silicon MFI structure molecular sieve having a high crystallinity even if a large amount of tetrapropylammonium template agent is added.
Comparative example 3
1.1g of sodium hydroxide and 6.0g of cetyltrimethylammonium bromide are dissolved in 100g of water, 50.0g of silica sol is slowly added, the mixture is stirred for 2 hours at 50 ℃, the obtained mixture is transferred into a high-pressure reaction kettle, and crystallization is carried out for 48 hours at 170 ℃ to obtain a crystallized product; washing, filtering, drying and roasting the crystallized product at about 570 ℃ in sequence to obtain a molecular sieve product;
XRD analysis shows that the molecular sieve product has an amorphous structure; thus, it is apparent from examples 1 to 8 and comparative example 3 that pure silicon MFI structure molecular sieves cannot be directly synthesized by adding only cetyltrimethylammonium salt without adding seed crystals when using an inorganic silicon source as a raw material for synthesizing molecular sieves.
Comparative example 4
Dissolving 1.1g of sodium hydroxide in 100g of water, slowly adding 50.0g of silica sol, stirring at 50 ℃ for 2 hours, slowly adding 5.0g of seed crystal liquid A, and stirring at 50 ℃ for 3 hours to obtain crystallized gel; transferring the crystallized gel into a high-pressure reaction kettle, and crystallizing for 48 hours at 170 ℃ to obtain a crystallized product; washing, filtering, drying and roasting the crystallized product at about 570 ℃ in sequence to obtain a molecular sieve product;
XRD analysis shows that the molecular sieve product has an amorphous structure; thus, it is apparent from examples 1 to 8 and comparative example 4 that pure silicon MFI structure molecular sieves cannot be directly synthesized by adding only seed crystals without adding cetyltrimethylammonium salt when using an inorganic silicon source as a raw material for synthesizing molecular sieves.
In addition, in combination with comparative example 3, comparative example 4 and examples 1 to 8, it was demonstrated that the seed crystal and the cetyltrimethylammonium salt exert a synergistic auxiliary crystallization effect under the preparation system of the present invention.
The silicon source, quaternary ammonium salt, seed crystal and addition amount thereof, material ratio, crystallization condition and structure of the obtained product used in each example are summarized in Table 2.
TABLE 2
Figure BDA0003438719820000151
Note that: silicon source a Refers to a silicon source (silicon source in examples) as a raw material for synthesizing a molecular sieve a Refers to a first silicon source); material proportioning b Refers to a silicon source a In SiO form 2 The alkali source is calculated as metal oxide (Na 2 O) the long-chain alkyl quaternary ammonium salt is represented by quaternary ammonium cation (A) + ) Metering the seed crystal by SiO 2 Meter, silicon source a The molar ratio of the materials used in water, alkali source, seed crystal, etc.
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. The preparation method of the pure silicon MFI structure molecular sieve is characterized by comprising the following steps:
(1) Stirring the mixed solution containing the first silicon source, the alkali source, the long-chain alkyl quaternary ammonium salt and water at 20-80 ℃ for 0.5-48 h to obtain a mixed system; the first silicon source comprises an inorganic silicon source, the long-chain alkyl quaternary ammonium salt is provided with long-chain alkyl, and the carbon number of the long-chain alkyl is not less than 8;
(2) Adding seed crystal into the mixed system to prepare first crystallization gel;
(3) And (3) carrying out crystallization reaction on the first crystallization gel under a hydrothermal condition to obtain the pure silicon MFI structure molecular sieve.
2. The method of claim 1, wherein the first silicon source is SiO 2 Calculated by metal oxide, long-chain alkyl quaternary ammonium salt calculated by quaternary ammonium cation, seed crystal calculated by SiO 2 The mole ratio of the seed crystal to the first silicon source is 0.002-0.250: 1, the mole ratio of the alkali source to the first silicon source is 0.04-0.50: 1, the molar ratio of the long-chain alkyl quaternary ammonium salt to the first silicon source is 0.003-0.125: 1, the mole ratio of water to the first silicon source is 15-120: 1.
3. the method according to claim 1, wherein the long-chain alkyl quaternary ammonium salt has 1 long-chain alkyl group and 3 short-chain alkyl groups, and the number of carbons in the short-chain alkyl groups is 1 to 6.
4. The method according to claim 1 or 3, wherein the number of carbons in the long-chain alkyl group is 8 to 22.
5. The method according to claim 4, wherein the long-chain alkyl quaternary ammonium salt comprises at least one of cetyltrimethylammonium bromide, cetyltrimethylammonium hydroxide, cetyltrimethylammonium chloride, cetyltrimethylammonium bisulfate, cetyltriethylammonium chloride, dodecyltrimethylammonium bromide, and dodecyltrimethylammonium hydroxide.
6. The method according to claim 1, wherein the inorganic silicon source comprises at least one of silica sol, solid silica gel, white carbon black, water glass; and/or the alkali source comprises sodium hydroxide and/or potassium hydroxide.
7. The method according to claim 1, wherein in the step (2), the first crystallized gel is obtained by adding seed crystals to the mixed system and stirring the mixture at 20 to 80 ℃ for 0.5 to 48 hours.
8. The method according to claim 1, wherein the crystallization reaction is carried out at a temperature of 120 to 190 ℃ and/or the crystallization reaction is carried out for a time of 12 to 120 hours.
9. The method according to claim 1, wherein in the step (2), a seed crystal liquid is added to the mixed system to realize the addition of seed crystal thereto, and the preparation process of the seed crystal liquid comprises:
will be the firstMixing a second silicon source, a template agent and water to prepare second crystal gel; the second silicon source comprises at least one of ethyl silicate, silica sol, solid silica gel, white carbon black and water glass, and the template agent comprises tetrapropylammonium salt and/or tetraethylammonium salt; second silicon source is SiO 2 The molar ratio of the template agent to the second silicon source is 0.09-0.5: 1, the mole ratio of water to the second silicon source is 10-100: 1, a step of;
crystallizing the second crystallized gel at 70-130 ℃ for 12-72 h to obtain the seed crystal liquid.
10. A pure silicon MFI structure molecular sieve, characterized by being prepared according to the preparation method of any one of claims 1-9.
CN202111625585.2A 2021-12-28 2021-12-28 Pure silicon MFI structure molecular sieve and preparation method thereof Pending CN116354359A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111625585.2A CN116354359A (en) 2021-12-28 2021-12-28 Pure silicon MFI structure molecular sieve and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111625585.2A CN116354359A (en) 2021-12-28 2021-12-28 Pure silicon MFI structure molecular sieve and preparation method thereof

Publications (1)

Publication Number Publication Date
CN116354359A true CN116354359A (en) 2023-06-30

Family

ID=86925631

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111625585.2A Pending CN116354359A (en) 2021-12-28 2021-12-28 Pure silicon MFI structure molecular sieve and preparation method thereof

Country Status (1)

Country Link
CN (1) CN116354359A (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103073020A (en) * 2012-11-08 2013-05-01 大连理工大学 Preparation method and application of hierarchical zeolite molecular sieve
CN103447078A (en) * 2013-09-06 2013-12-18 中国科学院金属研究所 Nano MFI-type molecular sieve with hierarchical pore structure and preparation method and application thereof
CN105645429A (en) * 2014-12-06 2016-06-08 中国石油化工股份有限公司 Method for synthesizing Silicalite-2 total silicon molecular sieve
WO2018086343A1 (en) * 2016-11-10 2018-05-17 南京工业大学 Method of preparing hierarchical porous channel molecular sieve membrane and application thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103073020A (en) * 2012-11-08 2013-05-01 大连理工大学 Preparation method and application of hierarchical zeolite molecular sieve
CN103447078A (en) * 2013-09-06 2013-12-18 中国科学院金属研究所 Nano MFI-type molecular sieve with hierarchical pore structure and preparation method and application thereof
CN105645429A (en) * 2014-12-06 2016-06-08 中国石油化工股份有限公司 Method for synthesizing Silicalite-2 total silicon molecular sieve
WO2018086343A1 (en) * 2016-11-10 2018-05-17 南京工业大学 Method of preparing hierarchical porous channel molecular sieve membrane and application thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
HONGYAO LI ET AL.: "Controllable fabrication of single-crystalline, ultrafine and high-silica hierarchical ZSM-5 aggregates via solid-like state conversion", 《RSC ADVANCES》, vol. 7, 12 May 2017 (2017-05-12), pages 25606 *

Similar Documents

Publication Publication Date Title
CN101890363B (en) Preparation method for mesopore-micropore core-shell composite molecular sieve catalyst
CN106830007B (en) With multi-stage porous SSZ-13 molecular sieve catalyst and its synthetic method and application
CN106475131B (en) A kind of graphene/molecular sieve composite catalyst and preparation method thereof
JP4744530B2 (en) Synthesis method of beta zeolite using diethylenetriamine
KR20070001216A (en) Synthesis of zsm-48 crystals with heterostructural, non zsm-48, seeding
CN102666385A (en) Method of preparing zsm-5 zeolite using nanocrystalline zsm-5 seeds
Wang et al. Preparation of high silica microporous zeolite SSZ-13 using solid waste silica fume as silica source
CN107777700A (en) A kind of molecular sieves of step hole HZSM 5 and preparation method thereof
CN112110457B (en) Preparation method of directionally stacked and grown ZSM-5 nanosheet aggregate
KR101950552B1 (en) Synthesis of zsm-5 crystals with improved morphology
CN108862309A (en) A kind of NaY molecular sieve aggregation and preparation method thereof with nano-micro structure
CN106608636A (en) Preparation method for EUO-structured or NES-structured molecular sieve
CN112794338A (en) ZSM-5 molecular sieve and preparation method and application thereof
KR0158759B1 (en) Method for mesoporous composition
CN1749161A (en) Hard template synthetic composite hole zeolite molecular sieve and its preparing method
CN106587102A (en) Synthetic method of ZSM-12 type zeolite molecular sieve
JP5555192B2 (en) Novel pentasil-type zeolite and synthesis method thereof
CN103043681A (en) Preparation method of nano layered ZSM (Zeolite Molecular Sieve)-5 zeolite molecular sieve
CN112661167B (en) Synthesis method of nano mordenite molecular sieve and molecular sieve
JP5580639B2 (en) Novel ZSM-5 type zeolite particles and synthesis method thereof
CN116354359A (en) Pure silicon MFI structure molecular sieve and preparation method thereof
CN109694086B (en) Preparation method of nano ZSM-5 zeolite molecular sieve aggregate
CN115010146B (en) Multistage hole ZSM-5 nano aggregate molecular sieve and preparation method thereof
CN105621439B (en) A kind of synthetic method of Beta zeolites
JP2000053413A (en) Highly heat-resistant mesoporous silica and its production

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination