CN113979444B - Preparation method of molecular sieve with FER structure and molecular sieve with FER structure - Google Patents

Preparation method of molecular sieve with FER structure and molecular sieve with FER structure Download PDF

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CN113979444B
CN113979444B CN202010733011.6A CN202010733011A CN113979444B CN 113979444 B CN113979444 B CN 113979444B CN 202010733011 A CN202010733011 A CN 202010733011A CN 113979444 B CN113979444 B CN 113979444B
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mixture
molecular sieve
sio
source
aluminum
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CN113979444A (en
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祁晓岚
王煜
顾士庆
管卉
李旭光
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China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
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Sinopec Shanghai Research Institute of Petrochemical Technology
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
    • C01B39/02—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/65—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the ferrierite type, e.g. types ZSM-21, ZSM-35 or ZSM-38, as exemplified by patent documents US4046859, US4016245 and US4046859, respectively
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
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    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
    • C01B39/02—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
    • C01B39/44—Ferrierite type, e.g. types ZSM-21, ZSM-35 or ZSM-38
    • 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
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM

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Abstract

The invention provides a molecular sieve with FER structure and a preparation method thereof, comprising the following steps: a mixture of a silicon source, an aluminum source, an alkali source, an imidazole structure directing agent and water is crystallized. The molecular sieve is a platy molecular sieve with a FER structure, and the crystal thickness is 15-90nm, so that the molecular sieve is beneficial to the diffusion of molecules and is not easy to accumulate carbon when used as a catalyst; the silicon-aluminum ratio is more than 25 and less than 60, which breaks through the limit that the prior art can only synthesize the sheet ZSM-35 molecular sieve with low silicon-aluminum ratio (< 25), and is beneficial to expanding the application range.

Description

Preparation method of molecular sieve with FER structure and molecular sieve with FER structure
Technical Field
The invention relates to a preparation method of a molecular sieve with a FER structure and the molecular sieve with the FER structure.
Background
Molecular sieves having the FER structure are defined by the International molecular sieve Association, the basic structural units of which are five-membered rings, which are skillfully linked by ten-membered rings and six-membered rings, and ZSM-35 molecular sieves and ferrierite are representative of such molecular sieves.
Ferrierite is a natural mineral, whereas ZSM-35 molecular sieve was synthesized for the first time by hydrothermal method using hexamethylenediamine as an organic template agent from the Plank of Mobil company in 1977 [ Plank C J, rosin E J, rubin M K.crystal zeolite and method of preparing same, U.S. Pat. No. 3, 4016245.1977]. The pore canal structure of ZSM-35 molecular sieve is a two-dimensional cross pore canal system composed of five-membered ring, eight-membered ring and ten-membered ring, wherein the diameter of ten-membered ring pore canal parallel to [001] direction is 0.42nm×0.54nm, and the diameter of eight-membered ring pore canal parallel to [010] direction is 0.35nm×0.48 nm) [ Zeolite.1994, 14 (6): 458-461].
Because of the unique pore structure, the ferrierite molecular sieve is mainly applied to reactions such as isobutene preparation by n-butene skeletal isomerization, hexene skeletal isomerization, butene polymerization and the like in the catalytic field. However, ferrierite is prone to side reactions during catalytic reactions and carbon deposition, which in turn results in reduced catalytic performance. In general, in the catalytic reaction process, the mass transfer rate of reactant molecules inside a molecular sieve pore canal is far smaller than that of reactant molecules on the surface of the molecular sieve, and aggregation and carbon deposition of molecules easily occur inside the pore canal, so that the service life of the catalyst is shortened [ Holm M S, taarning E, egeblad K and Christensen C h.catalysis Today,2011, 168:3-16]. Therefore, attempts have been made to reduce the diffusion limit by increasing the pore size of the catalyst or shortening the diffusion distance in order to improve the reactant and product diffusion properties and prevent deactivation of the carbon deposit.
The early ferrierite molecular sieve is synthesized artificially in inorganic system without organic template agent, and Na is needed in the synthesis system + And K + Exist to balance the charge in the backbone, and the crystallization temperature is high. The molecular sieve synthesized under the system has lower silicon-aluminum ratio (Si/Al) and purity, and mordenite can be easily generatedHetero-crystalline phases such as analcite.
At present, when a hydrothermal crystallization method is adopted to synthesize ferrierite or ZSM-35 molecular sieve, an organic template agent is generally required. Typical templating agents are n-butylamine [ China petrochemical Co., ltd., ZL200710304472.6, 2011.06.15], cyclohexylamine [ China petrochemical Co., ltd., ZL201310370348.5, 2017.03.01], [ Dalian heterogeneous catalyst Co., ltd., ZL 201210120962.1, 2014.07.16], ethylenediamine [ China Petroleum gas Co., northeast Petroleum university, ZL201410784583.1, 2016.07.13], tetrahydrofuran, piperidine, pyridine [ Kamimura Y, kowenje C, yamanaka K, et al Synthesis of hydrophobic siliceous ferrierite by using pyridine and sodium fluoride [ J ]. Microporous Mesoporous Mater.,2013, 181:154-159 ], or pyrrolidine [ US 5516959 ]. Ferrierite obtained by a conventional method tends to have relatively large grains [ Szosta K R.hand book of Molecular Sieves; van NostrandReinhold New York, 1992. At present, synthesis of ferrierite or ZSM-35 molecular sieve by using imidazole and similar compounds as template agents has not been reported.
201410784583.1[ China Petroleum and Natural gas stock Co., university of northeast, 2016.07.13]]The preparation process of small grain ZSM-35 molecular sieve includes the following steps: uniformly mixing a silicon source, an aluminum source, an alkali source, a template agent and water to obtain a colloid solution, wherein the mole ratio of the components is as follows: siO (SiO) 2 /Al 2 O 3 =18.5-28.6, templating agent/SiO 2 ＝0.81-1.25、OH - /SiO 2 ＝0.03-0.18、H 2 O/SiO 2 /(=10-26; crystallizing the colloid solution at 15-80deg.C for 5-30 hr, and then crystallizing at 150-200deg.C for 10-30 hr; the small-grain ZSM-35 molecular sieve is prepared after filtering, washing and drying. The ZSM-35 molecular sieve is spherical, and the minimum grain size can reach about 0.5 mu m.
20151046231. X [ university of Huadong, 2017.07.04] discloses a method for synthesizing nano platy ferrierite, which is characterized in that inorganic silicon source, aluminum source, alkali source and piperidine, piperazine, tetrahydrofuran or hexamethylenediamine are mixed, then cetyl trimethyl ammonium bromide (CTABr) is introduced and stirred at room temperature, and then crystallized, and the obtained molecular sieve has a thinner platy composition, but the platy bonding is tight.
CN108793189a [ university of petroleum in china (beijing), 2018.11.13] discloses a layered nano-sheet ferrierite molecular sieve, its preparation method and use, its sheet thickness is between 30-80nm, the synthesis requires two templates, the first template R1 is pyridine, pyrrole, furan, piperidine, pyrrolidine, tetrahydrofuran or cyclohexylamine; the second template R2 is n-butylamine, ethylenediamine, trimethylamine, 1, 3-diaminopropane, 1, 4-diaminobutane, tetramethylammonium hydroxide or tetraethylammonium hydroxide.
CN108946764a [ university of chinese petroleum (beijing), 2018.12.07] discloses a hierarchical pore nano ferrierite aggregate and a preparation method thereof, wherein the silicon-aluminum ratio is 10-1500, preferably 25-1000, more preferably 100-600; ferrierite aggregates are formed by aggregation of smaller crystallites, with particle sizes in the range 10-100nm, but not in a platy morphology. The templating agent used is an organic amine compound such as pyridine, piperidine, pyrrole, pyrrolidine, trimethylamine, 1, 3-diaminopropane, 1, 4-diaminobutane, cyclohexylamine, n-butylamine, ethylenediamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, or mixtures thereof. The auxiliary agent is NaF, NH4F, ethanol, glycol or a mixture thereof.
CN109110779A [ 2019.01.01, china petrochemical Co., ltd.) discloses a preparation method of ZSM-35 molecular sieve, which comprises the steps of mixing a silicon source, an aluminum source, alkali, water, an I organic template agent and an II organic template agent into a gel, performing hydrothermal crystallization, filtering, washing, drying and roasting to obtain the ZSM-35 molecular sieve, wherein the ZSM-35 molecular sieve has a flaky structure along the c-axis direction, but the silicon-aluminum ratio is not described. The first organic template agent is an amine compound, preferably ethylenediamine, cyclohexylamine or butanediamine; and/or the II organic template is a six-membered heterocyclic compound, preferably a nitrogen-containing six-membered heterocyclic compound, more preferably pyridine or piperidine.
CN109502606A [ Shandong Ji Luhua Xingao Kogyo Co., ltd., 2019.03.22] discloses a preparation method of a ZSM-35 molecular sieve, which comprises the following steps: a) Preparing an aluminum source, a complexing agent and water into a solution a, and aging to obtain an aging solution; b) Uniformly mixing a silicon source, an aluminum source, an alkali source, a template agent, water and ZSM-35 molecular sieve seed crystals to obtain gel b; c) Crystallizing at 50-150 deg.c for 1-36 hr; d) Adding the ageing liquid obtained in the step a) into the crystallization kettle in the step c), and crystallizing for 12-72 h at 150-180 ℃. The template agent is one or a mixture of more of cyclohexane, n-butylamine and ethylenediamine. The product is approximately elliptic, and the grain size is 100-500 nanometers.
From the above review, it is difficult to synthesize ZSM-35 molecular sieve nanoplatelets having a high silica to alumina ratio, although the method for synthesizing ZSM-35 molecular sieves is mature, thereby resulting in a great limitation in the use of ZSM-35 molecular sieves.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a synthesis method of the molecular sieve with the FER structure, which can obtain the molecular sieve with a flaky shape, smaller thickness and larger silicon-aluminum ratio than the conventional molecular sieve with low silicon-aluminum ratio and can meet different requirements of catalysts in chemical production.
According to a first aspect of the present invention, there is provided a method for preparing a molecular sieve according to the present invention, the method comprising: a mixture of a silicon source, an aluminum source, an alkali source, an imidazole structure directing agent and water is crystallized.
Preferably, the imidazole structure directing agent is at least one of imidazole, N-ethylimidazole, N-propylimidazole, 1-N-butylimidazole, 2-methylimidazole, 4-methylimidazole, 1, 2-dimethylimidazole and 2, 4-dimethylimidazole.
Preferably, the molar composition of the mixture comprises: siO (SiO) 2 /Al 2 O 3 5 to 500; SDA/SiO 2 0.01 to 1.5; OH (OH) - /SiO 2 0.01 to 0.50; h 2 O/SiO 2 9 to 35; wherein the silicon source is SiO 2 Metering Al as Al source 2 O 3 Counting the alkali source by OH - And (5) counting.
Preferably, the molar composition of the mixture comprises: siO (SiO) 2 /Al 2 O 3 10 to 400; SDA/SiO 2 0.05 to 1.2; OH (OH) - /SiO 2 0.05 to 0.40; h 2 O/SiO 2 12-30; wherein the silicon source is SiO 2 Metering Al as Al source 2 O 3 Counting the alkali source by OH - And (5) counting.
Preferably, the silicon source comprises at least one of silica gel, silica sol and tetraalkyl silicate.
Preferably, the aluminum source includes at least one of sodium aluminate, aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum hydroxide, and aluminum isopropoxide.
Preferably, the alkali source is one or more of sodium hydroxide, potassium hydroxide and ammonia.
Preferably, the crystallization temperature is 140 to 190 ℃, preferably 150 to 175 ℃.
Preferably, the crystallization time is 20 to 400 hours, preferably 30 to 80 hours.
Preferably, the feedstock contains seed crystals, preferably seed crystals/SiO, on an oxide basis 2 The weight ratio of (2) is 1-20:100, preferably 3-15:100; more preferably, the seed crystals are ZSM-35 molecular sieves.
Preferably, the feedstock contains seed crystals, the process comprising:
(1) Aging the solution containing the aluminum source and the seed crystal at 40-99 ℃ to obtain a mixture A;
(2) Mixing a silicon source with an imidazole structure directing agent to obtain a mixture B;
(3) Mixing the mixture B with the mixture A to obtain a mixture C, and controlling the pH value of the mixture C to be more than 9;
(4) Crystallizing the obtained mixture C, and then carrying out solid-liquid separation and heat treatment;
wherein step (1) and/or step (2) and/or step (3) are performed in the presence of an alkali source.
Preferably, the feedstock contains seed crystals, the process comprising:
(1) Aging a solution obtained by mixing an aluminum source, an imidazole structure directing agent and a seed crystal at 40-99 ℃ to obtain a mixture A;
(2) Mixing a silicon source with the mixture A to obtain a mixture B, and controlling the pH value of the mixture B to be more than 9;
(3) Crystallizing the obtained mixture B, and then performing solid-liquid separation and heat treatment, wherein the step (1) and/or the step (2) are/is performed in the presence of an alkali source.
Preferably, the temperature of aging is 50-70 ℃.
Preferably, the aging time is 1 to 10 hours, preferably 2 to 6 hours.
According to a second aspect of the present invention, there is provided a molecular sieve having a FER structure, the molecular sieve having a platelet morphology crystal structure with a crystal thickness of 15-90nm; the silicon-aluminum ratio is between 25 and 60.
Preferably, the molecular sieve has a crystal thickness of 20-80nm.
Preferably, the molecular sieve has a silica to alumina ratio of 27 to 55.
Compared with the prior art, the invention has the following advantages: the molecular sieve is a platy molecular sieve with a FER structure, the crystal thickness is 15-90nm, the molecular sieve is beneficial to the diffusion of molecules, and carbon deposition is not easy when the molecular sieve is used as a catalyst; the silicon-aluminum ratio is more than 25 and less than 60, which breaks through the limit that the prior art can only synthesize the sheet ZSM-35 molecular sieve with low silicon-aluminum ratio (< 25), and is beneficial to expanding the application range.
Drawings
FIG. 1 is an SEM photograph of a molecular sieve prepared according to example 1;
FIG. 2 is an XRD spectrum of the molecular sieve prepared in comparative example 1;
FIG. 3 is an SEM photograph of a molecular sieve prepared according to example 2;
fig. 4 is an SEM photograph of the molecular sieve prepared in example 3.
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
The invention provides a preparation method of a molecular sieve, which comprises the following steps: a mixture of a silicon source, an aluminum source, an alkali source, an imidazole structure directing agent and water is crystallized.
The invention adopts the imidazole structure guiding agent which is found for the first time, can improve the silicon-aluminum ratio of the molecular sieve with the flaky morphology crystal structure and improve the crystal thickness.
The types of imidazole structure directing agents according to the method of the present invention can be used in the present invention in a wide range of alternatives, such as C1-C4 alkyl substituted imidazoles, such as one or more of methylimidazole, ethylimidazole, propylimidazole and butylimidazole. For the present invention, it is preferable that the imidazole structure directing agent is at least one of imidazole, N-ethylimidazole, N-propylimidazole, 1-N-butylimidazole, 2-methylimidazole, 4-methylimidazole, 1, 2-dimethylimidazole and 2, 4-dimethylimidazole, and according to a preferred embodiment of the present invention, imidazole is preferable.
According to the invention, the composition of the mixture is not particularly limited, and the object of the invention can be achieved by the composition of the mixture of the usual synthetic molecular sieves, and for the invention, the molar composition of the mixture preferably comprises: siO (SiO) 2 /Al 2 O 3 5 to 500; SDA/SiO 2 0.01 to 1.5; OH (OH) - /SiO 2 0.01 to 0.50; h 2 O/SiO 2 9 to 35; wherein the silicon source is SiO 2 Metering Al as Al source 2 O 3 Counting the alkali source by OH - And (5) counting.
According to a more preferred embodiment of the invention, the molar composition of the preferred mixture comprises: siO (SiO) 2 /Al 2 O 3 10 to 400; SDA/SiO 2 0.05 to 1.2; OH (OH) - /SiO 2 0.05 to 0.40; h 2 O/SiO 2 12-30; wherein the silicon source is SiO 2 Metering Al as Al source 2 O 3 Counting the alkali source by OH - And (5) counting.
In the invention, the types of the silicon source, the aluminum source and the alkali source can be selected in a wider range, and the common silicon source, the aluminum source and the alkali source can be used in the invention. The following list is not limiting to the scope of the invention.
In the present invention, an inorganic silicon source such as silica, silica sol, silica-containing inorganic matters such as silica gel, and/or an organic silicon source such as organic silicate, which are commonly used in the art, may be used in the present invention, and according to a preferred embodiment of the present invention, the silicon source includes at least one of silica gel, silica sol, and tetraalkyl silicate.
In the present invention, the kinds of the aluminum sources, such as aluminum salts, aluminum oxide, aluminum hydroxide, etc., such as sodium aluminate, aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum hydroxide, etc., are widely selected, and the organic aluminum sources, such as organic aluminum alkoxide, which are commonly used in the art, may be used in the present invention, and according to a preferred embodiment of the present invention, the aluminum source includes at least one of sodium aluminate, aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum hydroxide, and aluminum isopropoxide.
In the present invention, the variety of the alkali source is wide in optional range, and common alkali sources can be used in the present invention, for example, sodium hydroxide, potassium hydroxide, ammonia water, etc.
According to a preferred embodiment of the invention, the feedstock preferably contains seed crystals, preferably seed crystals/SiO, as oxide 2 The weight ratio of (2) is 1-20:100, preferably 3-15:100.
According to a preferred embodiment of the present invention, the present invention is isomorphous seed crystals, preferably ZSM-35 molecular sieves.
According to a preferred embodiment of the present invention, the feedstock contains seeds and the molecular sieve is prepared by the steps of:
(1) Aging the solution containing the aluminum source and the seed crystal at 40-99 ℃ to obtain a mixture A;
(2) Mixing a silicon source with an imidazole structure directing agent to obtain a mixture B;
(3) Mixing the mixture B with the mixture A to obtain a mixture C, and controlling the pH value of the mixture C to be more than 9, preferably more than 11, more preferably 11-13.5;
(4) Crystallizing the obtained mixture C, and then carrying out solid-liquid separation and heat treatment;
wherein step (1) and/or step (2) and/or step (3) are carried out in the presence of an alkali source, and the purpose of step (1) and/or step (2) and/or step (3) being carried out in the presence of an alkali source is to adjust to a target pH value.
According to the invention, it is preferred that both step (1) and step (2) are carried out in the presence of an alkaline source to adjust the pH of both mixture A and mixture B to a value above 9, preferably above 11, more preferably between 11 and 13.5.
According to a preferred embodiment of the present invention, the molecular sieve is prepared by the steps of:
(1) Aging a solution obtained by mixing an aluminum source, an imidazole structure directing agent and a seed crystal at 40-99 ℃ to obtain a mixture A;
(2) Mixing a silicon source with the mixture A to obtain a mixture B, and controlling the pH value of the mixture B to be more than 9, preferably more than 11, more preferably 11-13.5;
(3) The obtained mixture B is crystallized, then solid-liquid separation and heat treatment are carried out, wherein the step (1) and/or the step (2) are/is carried out in the presence of an alkali source, and the purpose of the step (1) and/or the step (2) is to adjust the pH value to a target pH value.
According to the invention, it is preferred that both step (1) and step (2) are carried out in the presence of an alkaline source to adjust the pH of both mixture A and mixture B to a value above 9, preferably above 11, more preferably between 11 and 13.5.
According to a preferred embodiment of the invention, the temperature of the ageing is 50-70 ℃.
According to the invention, the aging time is preferably from 1 to 10 hours, more preferably from 2 to 6 hours.
According to a preferred embodiment of the invention, the crystallization temperature is 140 to 190 ℃, preferably 150 to 175 ℃.
According to a preferred embodiment of the invention, the crystallization time is 20 to 400 hours, preferably 30 to 80 hours.
The methods of operation and handling involved in the present invention are conventional in the art, unless specifically stated otherwise.
The molecular sieve of the present invention can be synthesized by the method of the present invention.
The invention provides a molecular sieve with FER structure, which has a flaky morphology crystal structure, and the crystal thickness is 15-90nm; the silicon-aluminum ratio is between 25 and 60.
According to a preferred embodiment of the invention, the molecular sieve has a crystal thickness of 20-80nm.
According to a preferred embodiment of the invention, the molecular sieve has a silica to alumina ratio of 27 to 55.
The apparatus used in the present invention is a conventional apparatus in the art unless otherwise specified.
The raw materials involved in the specific embodiment of the invention are as follows:
(A) Silica sol: containing SiO 2 40% by weight, commercial product;
(B) Sodium aluminate: containing Al 2 O 3 41% by weight, commercial product;
(C) Imidazole: 99% by weight, commercial product;
(D) Sodium hydroxide: 96% by weight, commercial product;
(E) Potassium hydroxide: 85% by weight, commercially available.
The detection method according to the embodiment of the invention comprises the following steps:
(1) Determination of molecular sieve thickness:
and (3) introducing the SEM picture of the prepared molecular sieve into Nano Measurer software, calibrating a scale, performing software measurement on the thickness of a molecular sieve sheet, ensuring that the total number of molecular sieve samples is more than or equal to 100, obtaining the thickness distribution of the sheet molecular sieve, and measuring the average thickness of the molecular sieve.
(2) Determination of the silicon-aluminum ratio of the molecular sieves:
the molecular sieve composition is measured by adopting an ICP-AES internal standard method (analysis and test technology and instrument, 2004,10 (1), 30-33), and the silicon-aluminum ratio of the molecular sieve is obtained by calculation according to the content measurement results of Si and Al elements.
(3) Determination of molecular sieve crystallinity: the diffraction pattern of the sample was recorded in the range of 2θ=5 to 50 ° using a conventional X-ray diffractometer, with a tube voltage of 40kV, a tube current of 40mA, a scan speed of 10 °/min. The comparative example 1 was used to obtain a reference sample, the relative crystallinity was set to 100, and the relative crystallinity of each sample was calculated by summing the peak intensities of 2θ= 9.302 °, 13.405 °, 22.319 °, 22.549 °, 23.083 °, 23.580 °, 24.299 °, 25.208 °, 25.577 ° and 28.401 ° with respect to the peak intensities of the reference sample (veribiest J., vansant e.d. dehydration, deammoniation and Thermal Stability of Ferrierite [ J ]. Bulletin des Soci et s Chimiques Belges,1986,95 (2): 75-81).
Example 1
(1) 1.233 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.72 g of potassium hydroxide and 2.83 g of imidazole are dissolved in 39 g of deionized water, 0.6 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 4 hours at 50 ℃ to obtain a mixture A;
(2) Slowly adding 23.2 g of silica sol under stirring, and then continuing stirring for one hour to obtain a mixture B, wherein the pH value of the mixture B is measured to be 12;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 175 ℃ for 40 hours. After crystallization, filtering, washing and drying are carried out, 11.2 g of solid product is obtained, and XRD detection results show that the solid product is molecular sieve nano-plate with FER structure, and the relative crystallinity is 173. The silicon-aluminum ratio of the molecular sieve is 35.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝31；SDA/SiO 2 ＝0.4；OH - /SiO 2 ＝0.08；H 2 O/SiO 2 ＝19。
XRD diffraction results of the molecular sieve having the FER structure obtained in example 1 are shown in Table 1.
TABLE 1
The SEM photograph of the molecular sieve having FER structure prepared in example 1 is shown in fig. 1, and the molecular sieve has an average thickness of 50nm, and the flaky crystals are randomly staggered instead of being regularly stacked.
Comparative example 1
1.233 g of sodium aluminate, 0.08 g of sodium hydroxide and 0.8 g of potassium hydroxide are dissolved in 39 g of deionized water, 13.9g of silica sol is slowly added under stirring, then 1.04 g of ZSM-35 molecular sieve seed crystal is added, stirring is continued for one hour, and the mixture is put into a stainless steel reaction kettle with a polytetrafluoroethylene lining and crystallized at 175 ℃ for 40 hours. After crystallization, 6.4 g of a solid product is obtained by filtering, washing and drying, and XRD detection results (shown in figure 2) show that the solid product contains a large amount of amorphous substances besides ZSM-35 molecular sieve, and the relative crystallinity of the solid product is set to be 100. The silicon-aluminum ratio of the molecular sieve is 19.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝19；OH - /SiO 2 ＝0.15；H 2 O/SiO 2 ＝28。
the average thickness of the molecular sieve having the FER structure prepared in comparative example 1 was 200 nm.
Example 2
(1) 1.648 g of sodium aluminate, 0.27 g of sodium hydroxide and 1.72 g of potassium hydroxide are dissolved in 25 g of deionized water to obtain a clear solution, ZSM-35 molecular sieve seed crystal 1.04 g is added, and the mixture is aged for 4 hours at 50 ℃ to obtain a mixture A;
(2) 15 g of deionized water and 7.03 g of imidazole are added into 13.9g of silica sol under stirring, and stirring is continued for 1 hour to obtain a mixture B;
(3) Mixing the mixture B with the mixture A under stirring to obtain a mixture C, wherein the pH value of the mixture C is measured to be 13;
(4) The obtained mixture C is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 175 ℃ for 40 hours. After crystallization, filtering, washing and drying are carried out, 8.2 g of solid product is obtained, and XRD detection results show that the solid product is ZSM-35 molecular sieve pure phase and has a relative crystallinity of 178. The molecular sieve has a silica to alumina ratio of 28.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝14；SDA/SiO 2 ＝1.1；OH - /SiO 2 ＝0.35；H 2 O/SiO 2 ＝29。
the SEM photograph of molecular sieve having FER structure prepared in example 2 is shown in FIG. 3, which has an average thickness of 35nm, and the flaky crystals are randomly staggered instead of being regularly stacked.
Example 3
(1) Dissolving 0.066 g of sodium aluminate, 0.04 g of sodium hydroxide, 0.72 g of potassium hydroxide and 0.96 g of imidazole in 15 g of deionized water, adding 0.6 g of ZSM-35 molecular sieve seed crystal, and aging for 2 hours at 70 ℃ to obtain a mixture A;
(2) Slowly adding 13.9g of silica sol into the mixture A under stirring, and continuing stirring for 1 hour to obtain a mixture B, wherein the pH value of the mixture B is 11;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 175 ℃ for 40 hours. After crystallization, filtering, washing and drying are carried out, 5.8 g of solid product is obtained, and XRD detection results show that the solid product is molecular sieve nano-plate with FER structure, and the relative crystallinity is 170. The molecular sieve has a silica to alumina ratio of 53.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝350；SDA/SiO 2 ＝0.15；OH - /SiO 2 ＝0.14；H 2 O/SiO 2 ＝14。
the SEM photograph of molecular sieve having FER structure prepared in example 3 is shown in FIG. 4, and the average thickness is 25nm, and the flaky crystals are randomly staggered instead of being regularly stacked.
Example 4
(1) 1.233 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.8 g of potassium hydroxide and 2.83 g of imidazole are dissolved in 39 g of deionized water to obtain a clear solution, 1.04 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 3 hours at 60 ℃ to obtain a mixture A;
(2) Slowly adding 13.9g of silica sol into the mixture A under stirring, and continuing stirring for 1 hour to obtain a mixture B, wherein the pH value of the mixture B is measured to be 12;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 150 ℃ for 72 hours. After crystallization, 7.2 g of solid product is obtained through filtration, washing and drying, and XRD detection results show that the solid product is ZSM-35 molecular sieve pure phase and has a relative crystallinity of 178. The molecular sieve has a silicon-aluminum ratio of 28 and an average thickness of 75nm, and the flaky crystals are randomly staggered instead of being stacked together regularly.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝19；SDA/SiO 2 ＝0.4；OH - /SiO 2 ＝0.15；H 2 O/SiO 2 ＝28。
example 5
(1) 1.233 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.8 g of potassium hydroxide and 4.08 g of N-propylimidazole are dissolved in 39 g of deionized water to obtain a clear solution, 1.04 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 4 hours at 50 ℃ to obtain a mixture A;
(2) Slowly adding 13.9g of silica sol into the mixture A under stirring, and continuing stirring for 1 hour to obtain a mixture B, wherein the pH value of the mixture B is measured to be 12;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 150 ℃ for 72 hours. After crystallization, filtering, washing and drying are carried out, 8.1 g of solid product is obtained, and XRD detection results show that the solid product is ZSM-35 molecular sieve pure phase, and the relative crystallinity is 166. The molecular sieve has a silicon-aluminum ratio of 27 and an average thickness of 60nm, and the flaky crystals are randomly staggered instead of being stacked together regularly.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝19；SDA/SiO 2 ＝0.4；OH - /SiO 2 ＝0.15；H 2 O/SiO 2 ＝28。
example 6
(1) 1.233 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.8 g of potassium hydroxide and 3.56 g of 1, 2-dimethyl imidazole are dissolved in 39 g of deionized water to obtain a clear solution, 1.04 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 4 hours at 50 ℃ to obtain a mixture A;
(2) Slowly adding 13.9g of silica sol into the mixture A under stirring, and continuing stirring for 1 hour to obtain a mixture B, wherein the pH value of the mixture B is measured to be 12;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 150 ℃ for 72 hours. After crystallization, 7.4 g of solid product is obtained through filtration, washing and drying, and XRD detection results show that the solid product is ZSM-35 molecular sieve pure phase and has relative crystallinity of 159. The molecular sieve has a silicon-aluminum ratio of 28 and an average thickness of 50nm, and the flaky crystals are randomly staggered instead of being stacked together regularly. The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝19；SDA/SiO 2 ＝0.4；OH - /SiO 2 ＝0.15；H 2 O/SiO 2 ＝28。
example 7
(1) 1.233 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.8 g of potassium hydroxide and 4.60 g of 1-n-butylimidazole are dissolved in 39 g of deionized water to obtain a clear solution, 1.04 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 4 hours at 50 ℃ to obtain a mixture A;
(2) Slowly adding 13.9g of silica sol into the mixture A under stirring, and continuing stirring for 1 hour to obtain a mixture B, wherein the pH value of the mixture B is measured to be 12;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 150 ℃ for 72 hours. After crystallization, 7.0 g of solid product is obtained through filtration, washing and drying, and XRD detection results show that the solid product is ZSM-35 molecular sieve pure phase and has a relative crystallinity of 161. The molecular sieve has a silicon-aluminum ratio of 25 and an average thickness of 50nm, and the flaky crystals are randomly staggered instead of being stacked together regularly.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝19；SDA/SiO 2 ＝0.4；OH - /SiO 2 ＝0.15；H 2 O/SiO 2 ＝28。
example 8
(1) 1.233 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.8 g of potassium hydroxide and 4.0 g of N-ethylimidazole are dissolved in 39 g of deionized water to obtain a clear solution, 1.04 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 4 hours at 50 ℃ to obtain a mixture A;
(2) Slowly adding 13.9g of silica sol into the mixture A under stirring, and continuing stirring for 1 hour to obtain a mixture B, wherein the pH value of the mixture B is measured to be 12;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 150 ℃ for 72 hours. After crystallization, 7.2 g of solid product is obtained through filtration, washing and drying, and XRD detection results show that the solid product is ZSM-35 molecular sieve pure phase and has a relative crystallinity of 162. The molecular sieve has a silicon-aluminum ratio of 29 and an average thickness of 70nm, and the flaky crystals are randomly staggered instead of being stacked together regularly.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝19；SDA/SiO 2 ＝0.4；OH - /SiO 2 ＝0.15；H 2 O/SiO 2 ＝28。
example 9
(1) 1.233 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.8 g of potassium hydroxide and 3.41 g of 2-methylimidazole are dissolved in 39 g of deionized water to obtain a clear solution, 1.04 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 4 hours at 50 ℃ to obtain a mixture A;
(2) Slowly adding 13.9g of silica sol into the mixture A under stirring, and continuing stirring for 1 hour to obtain a mixture B, wherein the pH value of the mixture B is measured to be 12;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 150 ℃ for 72 hours. After crystallization, 7.2 g of solid product is obtained through filtration, washing and drying, and XRD detection results show that the solid product is ZSM-35 molecular sieve pure phase and has a relative crystallinity of 168. The molecular sieve has a silicon-aluminum ratio of 28 and an average thickness of 70nm, and the flaky crystals are randomly staggered instead of being stacked together regularly.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝19；SDA/SiO 2 ＝0.4；OH - /SiO 2 ＝0.15；H 2 O/SiO 2 ＝28。
example 10
(1) 1.233 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.8 g of potassium hydroxide and 3.41 g of 4-methylimidazole are dissolved in 39 g of deionized water to obtain a clear solution, 1.04 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 4 hours at 50 ℃ to obtain a mixture A;
(2) Slowly adding 13.9g of silica sol into the mixture A under stirring, and continuing stirring for 1 hour to obtain a mixture B, wherein the pH value of the mixture B is measured to be 12;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 150 ℃ for 72 hours. After crystallization, 7.2 g of solid product is obtained through filtration, washing and drying, and XRD detection results show that the solid product is ZSM-35 molecular sieve pure phase and has a relative crystallinity of 166. The molecular sieve has a silicon-aluminum ratio of 28 and an average thickness of 70nm, and the flaky crystals are randomly staggered instead of being stacked together regularly.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝19；SDA/SiO 2 ＝0.4；OH - /SiO 2 ＝0.15；H 2 O/SiO 2 ＝28。
example 11
(1) 1.233 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.8 g of potassium hydroxide and 3.56 g of 2, 4-dimethyl imidazole are dissolved in 39 g of deionized water to obtain a clear solution, 1.04 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 4 hours at 50 ℃ to obtain a mixture A;
(2) Slowly adding 13.9g of silica sol into the mixture A under stirring, and continuing stirring for 1 hour to obtain a mixture B, wherein the pH value of the mixture B is measured to be 12;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 150 ℃ for 72 hours. After crystallization, 7.4 g of solid product is obtained through filtration, washing and drying, and XRD detection results show that the solid product is ZSM-35 molecular sieve pure phase and has a relative crystallinity of 158. The molecular sieve has a silicon-aluminum ratio of 28 and an average thickness of 50nm, and the flaky crystals are randomly staggered instead of being stacked together regularly. The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝19；SDA/SiO 2 ＝0.4；OH - /SiO 2 ＝0.15；H 2 O/SiO 2 ＝28。
example 12
(1) 2.6 g of sodium aluminate, 0.04 g of sodium hydroxide, 0.20 g of potassium hydroxide and 8.9 g of imidazole are dissolved in 48 g of deionized water to obtain a clear solution, 1.04 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 6 hours at 50 ℃ to obtain a mixture A;
(2) Slowly adding 13.9g of silica sol into the mixture A under stirring, and continuing stirring for 1 hour to obtain a mixture B, wherein the pH value of the mixture B is 13;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 150 ℃ for 72 hours. After crystallization, filtering, washing and drying are carried out, 9.4 g of solid product is obtained, and XRD detection results show that the solid product is ZSM-35 molecular sieve pure phase and has the relative crystallinity of 143. The molecular sieve has a silicon-aluminum ratio of 26 and an average thickness of 85nm, and the flaky crystals are randomly staggered instead of being stacked together regularly.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝9；SDA/SiO 2 ＝1.4；OH - /SiO 2 ＝0.04；H 2 O/SiO 2 ＝34。
example 13
(1) Dissolving 0.05 g of sodium aluminate, 0.04 g of sodium hydroxide, 0.36 g of potassium hydroxide and 0.255 g of imidazole in 10 g of deionized water to obtain a clear solution, adding 1.04 g of ZSM-35 molecular sieve seed crystal, and aging for 6 hours at 50 ℃ to obtain a mixture A;
(2) Slowly adding 13.9g of silica sol into the mixture A under stirring, and continuing stirring for 1 hour to obtain a mixture B, wherein the pH value of the mixture B is 11;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized for 96 hours at 140 ℃. After crystallization, filtering, washing and drying are carried out, 5.4 g of solid product is obtained, and XRD detection results show that the solid product is ZSM-35 molecular sieve pure phase and has a relative crystallinity of 124. The molecular sieve has a silicon-aluminum ratio of 59 and an average thickness of 18nm, and the flaky crystals are randomly staggered instead of being stacked together regularly.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝450；SDA/SiO 2 ＝0.04；OH - /SiO 2 ＝0.07；H 2 O/SiO 2 ＝11。
example 14
(1) 1.233 g of sodium aluminate, 0.04 g of sodium hydroxide, 0.36 g of potassium hydroxide and 8.75 g of imidazole are dissolved in 39 g of deionized water to obtain a clear solution, 0.6 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 4 hours at 50 ℃ to obtain a mixture A;
(2) Slowly adding 48.23 g of silica sol into the mixture A under stirring, and continuing stirring for 1 hour to obtain a mixture B, wherein the pH value of the mixture B is 11;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 175 ℃ for 40 hours. After crystallization, filtering, washing and drying are carried out, 14.5 g of solid product is obtained, and XRD detection results show that the solid product is a ZSM-35 molecular sieve pure phase and has a relative crystallinity of 135. The molecular sieve has a silicon-aluminum ratio of 49 and an average thickness of 60nm, and the flaky crystals are randomly staggered instead of being stacked together regularly.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝65；SDA/SiO 2 ＝0.4；OH - /SiO 2 ＝0.02；H 2 O/SiO 2 ＝12。
example 15
(1) 1.233 g of sodium aluminate, 0.41 g of sodium hydroxide, 2.1 g of potassium hydroxide and 2.83 g of imidazole are dissolved in 39 g of deionized water to obtain a clear solution, 1.04 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 4 hours at 50 ℃ to obtain a mixture A;
(2) Slowly adding 13.9g of silica sol into the mixture A under stirring, and continuing stirring for 1 hour to obtain a mixture B, wherein the pH value of the mixture B is measured to be 12;
(3) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 175 ℃ for 40 hours. After crystallization, 7.0 g of solid product is obtained through filtration, washing and drying, and XRD detection results show that the solid product is a ZSM-35 molecular sieve pure phase and has a relative crystallinity of 142. The molecular sieve has a silicon-aluminum ratio of 26 and an average thickness of 20nm, and the flaky crystals are randomly staggered instead of being stacked together regularly.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝19；SDA/SiO 2 ＝0.4；OH - /SiO 2 ＝0.45；H 2 O/SiO 2 ＝28。
example 16
Prepared according to the method of example 15, except that the following steps are performed:
(1) 1.04 g of ZSM-35 molecular sieve seed crystal, 13.9g of silica sol, 1.233 g of sodium aluminate, 0.41 g of sodium hydroxide, 2.1 g of potassium hydroxide and 2.83 g of imidazole are dissolved in 39 g of deionized water to obtain a mixture, and the pH value of the mixture is measured to be 12;
(3) The resulting mixture was placed in a stainless steel reactor with polytetrafluoroethylene liner and crystallized at 175 ℃ for 40 hours. After crystallization, 7.0 g of solid product is obtained through filtration, washing and drying, and XRD detection results show that the solid product is ZSM-35 molecular sieve pure phase and has a relative crystallinity of 112. The molecular sieve has a silicon-aluminum ratio of 25 and an average thickness of 40nm, and the flaky crystals are randomly staggered instead of being stacked together regularly.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝19；SDA/SiO 2 ＝0.4；OH - /SiO 2 ＝0.45；H 2 O/SiO 2 ＝28。
the preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims (16)

1. A method for preparing a molecular sieve of FER structure, comprising: crystallizing a mixture formed by raw materials containing a silicon source, an aluminum source, an alkali source, an imidazole structure directing agent SDA and water; the imidazole structure directing agent SDA is imidazole and/or C1-C4 alkyl substituted imidazole; the molar composition of the mixture comprises: siO (SiO) 2 /Al 2 O 3 5 to 500; SDA/SiO 2 0.01 to 1.5; OH (OH) - /SiO 2 0.01 to 0.50; h 2 O/SiO 2 9 to 35; wherein the silicon source is SiO 2 Metering Al as Al source 2 O 3 Counting the alkali source by OH - And (5) counting.
2. The preparation method according to claim 1, wherein,
the imidazole structure guiding agent SDA is at least one of imidazole, N-ethylimidazole, N-propylimidazole, 1-N-butylimidazole, 2-methylimidazole, 4-methylimidazole, 1, 2-dimethylimidazole and 2, 4-dimethylimidazole; and/or
The silicon source comprises at least one of silica gel, silica sol and tetraalkyl silicate; and/or
The aluminum source comprises at least one of sodium aluminate, aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum hydroxide and aluminum isopropoxide; and/or
The alkali source is one or more of sodium hydroxide, potassium hydroxide and ammonia water.
3. The preparation method according to claim 2, wherein the imidazole structure directing agent SDA is imidazole.
4. The process according to any one of claim 1 to 3, wherein,
the crystallization temperature is 140-190 ℃; and/or
The crystallization time is 20-400 hours.
5. The process according to any one of claim 1 to 3, wherein,
the molar composition of the mixture comprises: siO (SiO) 2 /Al 2 O 3 10 to 400; SDA/SiO 2 0.05 to 1.2; OH (OH) - /SiO 2 0.05 to 0.40; h 2 O/SiO 2 12-30; wherein the silicon source is SiO 2 Metering Al as Al source 2 O 3 Counting the alkali source by OH - Counting; and/or
The crystallization temperature is 150-175 ℃; and/or
The crystallization time is 30-80 h.
6. The process according to any one of claims 1 to 3, wherein the raw material contains seed crystals, in terms of oxide, seed crystals/SiO 2 The weight ratio of the components is 1-20:100.
7. The method of claim 6, whereinSeed crystal/SiO in terms of oxide 2 The weight ratio of the components is 3-15:100.
8. The method according to claim 6, wherein the seed crystal is ZSM-35 molecular sieve.
9. A production method according to any one of claims 1 to 3, wherein the raw material contains seed crystals, the method comprising:
(1) Aging the solution containing the aluminum source and the seed crystal at 40-99 ℃ to obtain a mixture A;
(2) Mixing a silicon source with an imidazole structure directing agent to obtain a mixture B;
(3) Mixing the mixture B with the mixture A to obtain a mixture C, and controlling the pH value of the mixture C to be more than 9;
(4) Crystallizing the obtained mixture C, and then carrying out solid-liquid separation and heat treatment;
wherein step (1) and/or step (2) and/or step (3) are performed in the presence of an alkali source.
10. A production method according to any one of claims 1 to 3, wherein the raw material contains seed crystals, the method comprising:
(1) Aging a solution obtained by mixing an aluminum source, an imidazole structure directing agent and a seed crystal at 40-99 ℃ to obtain a mixture A;
(2) Mixing a silicon source with the mixture A to obtain a mixture B, and controlling the pH value of the mixture B to be more than 9;
(3) Crystallizing the obtained mixture B, and then performing solid-liquid separation and heat treatment;
wherein step (1) and/or step (2) is performed in the presence of an alkali source.
11. The preparation method according to claim 9, wherein,
the aging temperature is 50-70 ℃; and/or
The aging time is 1-10h.
12. The preparation method according to claim 10, wherein,
the aging temperature is 50-70 ℃; and/or
The aging time is 1-10h.
13. The preparation method according to claim 11 or 12, wherein the aging time is 2 to 6 hours.
14. A molecular sieve of FER structure prepared by the preparation method of any one of claims 1 to 13, the molecular sieve having a lamellar morphology crystal structure with a crystal thickness of 15 to 90nm; the molar ratio of silicon to aluminum is between 25 and 60.
15. The molecular sieve of claim 14, wherein the molecular sieve has a crystal thickness of 20-80nm.
16. The molecular sieve of claim 14 or 15, wherein the molecular sieve has a silica to alumina ratio of 27-55.
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