CN114436285B - Molecular sieve with FER structure and synthesis method and application thereof - Google Patents

Molecular sieve with FER structure and synthesis method and application thereof Download PDF

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CN114436285B
CN114436285B CN202011120877.6A CN202011120877A CN114436285B CN 114436285 B CN114436285 B CN 114436285B CN 202011120877 A CN202011120877 A CN 202011120877A CN 114436285 B CN114436285 B CN 114436285B
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molecular sieve
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CN114436285A (en
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祁晓岚
王煜
管卉
石张平
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China Petroleum and Chemical Corp
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
    • C01B39/44—Ferrierite type, e.g. types ZSM-21, ZSM-35 or ZSM-38
    • C01B39/445—Ferrierite type, e.g. types ZSM-21, ZSM-35 or ZSM-38 using at least one organic template directing agent
    • 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
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    • B01J35/40—Catalysts, in general, characterised by their form or physical properties characterised by dimensions, e.g. grain size
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    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
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    • C07C5/22—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by isomerisation
    • C07C5/2206—Catalytic processes not covered by C07C5/23 - C07C5/31
    • C07C5/222—Catalytic processes not covered by C07C5/23 - C07C5/31 with crystalline alumino-silicates, e.g. molecular sieves
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    • C01—INORGANIC CHEMISTRY
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    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/20—Particle morphology extending in two dimensions, e.g. plate-like
    • C01P2004/22—Particle morphology extending in two dimensions, e.g. plate-like with a polygonal circumferential shape
    • 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
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    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
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Abstract

The invention relates to the field of molecular sieves, and particularly provides a method for synthesizing a molecular sieve with a FER structure, which comprises the step of crystallizing a mixture formed by raw materials containing a silicon source, an aluminum source, an alkali source, a first template SDA1, a second template SDA2 and water, wherein the first template is selected from imidazole and/or imidazole analogues, and the second template is different from the first template. The invention provides a molecular sieve synthesized by the method and application thereof. Compared with the prior art, the molecular sieve synthesized by the invention is a molecular sieve nano-sheet with a FER structure, the silicon-aluminum ratio range is very wide, the crystal thickness is 10-150nm, the molecular diffusion is facilitated, and carbon deposition is not easy when the molecular sieve is used as a catalyst.

Description

Molecular sieve with FER structure and synthesis method and application thereof
Technical Field
The invention belongs to the field of catalysts, and particularly relates to a method for synthesizing a molecular sieve with an FER structure, a molecular sieve obtained by the method and application thereof.
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. The catalytic activity of ferrierite is mainly related to the number and distribution of active sites, and the microporous structure and distribution. 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 is easy to generate hetero-crystalline phases such as mordenite, analcite and the like.
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.
ZL201410784583.1[ China Petroleum and Natural gas stock Co., ltd., northeast Petroleum university, 2016.07.13]]The preparation process of small grain ZSM-35 molecular sieve with ethylenediamine as template agent includes adding seed crystal and two-stage crystallization to control crystallization process, and the molar 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 15-80 deg.c for 5-30 hr, and crystallizing at 150-200 deg.c for 10-30 hr to obtain small crystal ZSM-35 molecular sieve in spherical shape with crystal size as small as 0.5 microns.
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.
Compared with a single template synthetic route, the method for synthesizing the ZSM-35 molecular sieve by using the composite template system is more.
ZL 20151046231. X [ university of Huadong, university of teachers 2017.07.04 ]]The method for synthesizing nano flaky ferrierite is characterized by taking piperidine, tetrahydrofuran or hexamethylenediamine as a structure guiding agent Q, cetyl trimethyl ammonium bromide (CTABr) as a morphology control agent of a molecular sieve, wherein the molar ratio of the components is as follows: siO (SiO) 2 /Al 2 O 3 ＝15-200、Q/SiO 2 ＝0.03-0.5、CTABr/SiO2＝0.01-0.2、Me 2 O/SiO 2 ＝0.05-0.3、H 2 O/SiO 2 =5-60. The molecular sieve has a thinner lamellar composition, but the lamellar bonds are 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 petroleum (Beijing), 2018.12.07]Disclosed is a hierarchical pore nano ferrierite aggregate and a method for preparing the same, wherein the silica-alumina 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, NH 4 F. Ethanol, ethylene glycol, or mixtures 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.
In 2009, j.catalyst reports [ Pinar a B et al, template-controlled acidity and catalytic activity of ferrierite crystals.j.catalyst., 2009, 263 (2): 258-265 FER molecular sieves were synthesized in fluorous medium by using different template combinations (TMA, pyr, bmp) in the absence of inorganic cations, the Si/Al in the gel of all synthesized samples was 15.7, wherein the sample with TMA/bmp as template was in a bar-like structure, while the sample without bmp was higher in crystallinity and in a plate-like structure. Due to the presence of the fluorine medium, these crystals are larger in crystal size than the sample in the presence of sodium ions.
In 2013, microporous and Mesoporous Materials reports [ Kamimura Y et al Synthesis of hydrophobic siliceous ferrierite by using pyridine and sodium fluoride. Microrous and Mesoporous Materials 2013, 181:154-159] that pyridine is used as a template agent and NaF is used as a mineralizer in a hydrothermal system to successfully synthesize the high-silicon ferrierite with the silicon-aluminum ratio of 138.8-324, wherein the high-silicon ferrierite has a dish shape, the size of 5 mu m multiplied by 10 mu m and the thickness of about 200nm.
CN108147426a [ 2016.12.05, chinese petroleum and natural gas stock, inc.) discloses a method for synthesizing ZSM-35 molecular sieve by using a composite template agent, which comprises adding hexamethyleneimine into cyclohexylamine to prepare a composite template agent, using silica sol as silicon source, using sodium metaaluminate or sodium aluminate as aluminum source, adding NaZSM-35 molecular sieve seed crystal, and synthesizing ZSM-35 molecular sieve, but no molecular sieve morphology map is given.
From the above, although the method for synthesizing ZSM-35 molecular sieve is mature, it is difficult to synthesize ZSM-35 molecular sieve nanosheets having high crystallinity, thereby resulting in a great limitation in the application of ZSM-35 molecular sieve.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a method for preparing molecular sieve nano sheets with FER structures, wherein the molecular sieve prepared by the method has a flaky shape, smaller thickness and wider adjustable range of silicon-aluminum ratio, and meets different requirements on catalysts in chemical production.
According to a first aspect of the present invention, there is provided a process for synthesizing a molecular sieve having the FER structure, which comprises subjecting a mixture formed from a feedstock comprising a silicon source, an aluminium source, an alkali source, a first template SDA1, a second template SDA2 and water to a crystallization treatment, wherein the first template is selected from imidazole and/or an imidazole analogue, and the second template is different from the first template.
According to a second and third aspect of the present invention there is provided a molecular sieve synthesized in accordance with the method of the present invention and uses thereof.
Compared with the prior art, the molecular sieve synthesized by the invention is a molecular sieve nano-sheet with a FER structure, the silicon-aluminum ratio range is very wide, the crystal thickness is 10-150nm, the molecular diffusion is facilitated, and carbon deposition is not easy when the molecular sieve is used as a catalyst, namely the molecular sieve with the FER structure can be synthesized by the molecular sieve with the nano-sheet with the very wide silicon-aluminum ratio range.
The molecular sieves of the present invention are particularly useful in isomerization reactions, such as n-butene isomerization reactions.
Drawings
FIG. 1 is an SEM photograph of a molecular sieve prepared according to example 1;
fig. 2 is an SEM photograph of the molecular sieve prepared in comparative example 1.
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 method for synthesizing a molecular sieve with a FER structure, which comprises the step of crystallizing a mixture formed by raw materials containing a silicon source, an aluminum source, an alkali source, a first template SDA1, a second template SDA2 and water, wherein the first template is selected from imidazole and/or imidazole analogues, and the second template is different from the first template.
According to a preferred embodiment of the invention, the mixture contains seed crystals and/or a fluorine source. The acidity of the molecular sieve can be regulated by adding a fluorine source, and the crystallinity of the molecular sieve can be effectively improved by adding the seed crystal, so that the crystallization time is shortened.
According to a preferred embodiment of the invention, the molar ratio of seed crystals to silicon source, calculated as silica, is preferably 1-20:100, preferably 3-15:100; preferably, the seed crystal is selected from one or more of ZSM-35 and ZSM-5 molecular sieves, and more preferably ZSM-35 molecular sieves.
According to a preferred embodiment of the invention, the fluorine source is preferably selected from the group consisting of F - Gauge F - /SiO 2 0.005 to 0.50.
The fluorine source may be selected from a wide range of species in accordance with the method of the present invention, for example, one or more of sodium fluoride, potassium fluoride, ammonium fluoride and ammonium bifluoride, and for the present invention, it is preferred that the fluorine source is at least one of ammonium fluoride, sodium fluoride and potassium fluoride.
According to a preferred embodiment of the invention, the method comprises:
(1) Aging a solution containing an aluminum source, a first template agent SDA1 and seed crystals at 40-99 ℃ to obtain a mixture A;
(2) Adding a second template agent SDA2 under stirring;
(3) Adding a silicon source under stirring to obtain a mixture B, and controlling the pH value of the mixture B to be more than 9;
(4) Crystallizing the obtained mixture B, and then performing solid-liquid separation and heat treatment;
wherein step (1) and/or step (2) and/or step (3) and/or step (4) are performed in the presence of an alkaline source. The molecular sieve prepared by adopting the preferred embodiment can lead the synthesized molecular sieve to have the advantage of high crystallinity.
According to a preferred embodiment of the invention, the temperature of the ageing is 50-85 ℃, preferably 65-78 ℃.
According to a preferred embodiment of the invention, the aging time is from 0.5 to 20 hours, preferably from 1 to 15 hours.
According to a preferred embodiment of the present invention, a fluorine source is added in step (2). Therefore, the synthesized molecular sieve has the advantage of adjustable acidity.
According to a preferred embodiment of the invention, siO is present in the mixture 2 Silicon source, in Al 2 O 3 Aluminium source in terms of OH - The calculated molar composition of the alkali source, the template agent and the water is as follows: siO (SiO) 2 /Al 2 O 3 5 to 500; SDA1/SiO 2 0.01 to 1.5; SDA2/SiO 2 0.01 to 1.5; OH (OH) - /SiO 2 0.01 to 0.50; h 2 O/SiO 2 9 to 40.
According to a preferred embodiment of the invention, siO is present in the mixture 2 Silicon source, in Al 2 O 3 Aluminium source in terms of OH - The calculated molar composition of the alkali source, the template agent and the water is as follows: siO (SiO) 2 /Al 2 O 3 10 to 400; SDA1/SiO 2 0.05 to 1.2; SDA2/SiO 2 0.05 to 1.2; OH (OH) - /SiO 2 0.05 to 0.40; h 2 O/SiO 2 10 to 36.
According to the method provided by the invention, the molecular sieve obtained under the preferable formula has the advantages of high crystallinity, nano-sheet product morphology and the like.
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, and for the present invention, silica sol is preferred.
In the present invention, the types of the aluminum source may be widely selected, and inorganic aluminum source and/or organic aluminum source may be used in the present invention, for example, aluminum salt, aluminum oxide, aluminum hydroxide, etc., for example, sodium aluminate, aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum hydroxide, etc., and organic aluminum alkoxide may be used in the present invention, for example, aluminum isopropoxide, 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, and sodium aluminate is preferred for the present invention.
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 the method of the present invention, the first template may be of a wide range of types, such as C1-C4 alkyl substituted imidazoles, for example, one or more of methylimidazole, ethylimidazole, propylimidazole and butylimidazole. For the present invention, it is preferable that the first template 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.
The method according to the present invention, wherein the second template agent has a wide variety of optional ranges, and the template agents commonly used for synthesizing molecular sieves with FER structure can be used in the present invention, and for the present invention, it is preferable that the second template agent SDA2 is at least one of ethylenediamine, n-butylamine, cyclohexylamine, piperidine and pyridine, preferably one or more of ethylenediamine, n-butylamine and cyclohexylamine, more preferably at least two of ethylenediamine, n-butylamine and cyclohexylamine.
According to a preferred embodiment of the present invention, the molar ratio of the first template to the second template is selected in a wide range of SDA 1/sda2=0.05 to 10, preferably SDA 1/sda2=0.1 to 4, more preferably SDA 1/sda2=0.2 to 3. By adopting the preferable molar ratio, the crystallization effect with higher crystallinity and molecular sieve morphology control can be realized.
According to a preferred embodiment of the invention, the crystallization temperature is 120-190 ℃, preferably 130-180 ℃.
According to a preferred embodiment of the invention, the crystallization time is from 10 hours to 10 days, preferably from 1 to 7 days.
The invention provides a molecular sieve obtained by the synthesis method.
According to the present invention, it is preferable that the molecular sieve is nano-platelet.
According to the invention, the molecular sieve is preferably in the form of nanoplatelets, preferably having a crystal thickness of 10 to 150nm, preferably 15 to 120nm.
The molecular sieve according to the invention is particularly suitable for use in isomerisation reactions, in particular the invention provides in particular the use of the molecular sieve according to the invention in the isomerisation field, particularly preferably for n-butene isomerisation reactions.
The methods of operation and handling involved in the present invention are conventional in the art, unless specifically stated otherwise.
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) 2, 4-dimethylimidazole: 98% by weight, commercial product;
(E) 2-methylimidazole: 99% by weight, commercial product;
(F) N-propylimidazole: 99% by weight, commercial product;
(G) 1-n-butylimidazole: 99% by weight, commercial product;
(H) 1-ethyl-3 methyl-imidazole chloride: 97% by weight, commercial product;
(I) Ethylenediamine: 99% by weight, commercial product;
(J) N-butylamine: 98% by weight, commercial product;
(K) Cyclohexylamine: 99% by weight, commercial product;
(L) sodium hydroxide: 96% by weight, commercial product;
(M) potassium hydroxide: 85% by weight, commercial product;
(N) sodium fluoride: the content was 98% by weight, and the product was commercially available.
In order that the invention may be more readily understood, the invention will be described in detail below with reference to the following examples, which are given by way of illustration only and are not limiting of the scope of application of the invention.
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).
(4) Molecular sieves catalyze the isomerization reaction performance of normal butene: the evaluation was carried out in a miniature fixed bed tubular reactor at 320℃and 0.1MPa, with a mass space velocity of n-butene of 2h -1 Reaction 3d.
Example 1
(1) 1.233 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.72 g of potassium hydroxide and 2.10 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 10 hours at 65 ℃ to obtain a mixture A;
(2) 10.42 g of ethylenediamine is added with stirring;
(3) 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;
(4) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 175 ℃ for 40 hours. After crystallization is completed, 9.1 g of solid product is obtained by filtering, washing and drying, and the detection result shows that the solid product is a molecular sieve nano-sheet with a FER structure, the relative crystallinity is 175, the silicon-aluminum ratio is 28, and the average thickness of the sheet layer is 90 nanometers.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝31；SDA1/SiO 2 ＝0.2；SDA2/SiO 2 ＝1.1；OH - /SiO 2 ＝0.08；H 2 O/SiO 2 ＝19。
SEM photographs of molecular sieve nanoplatelets having FER structure prepared in example 1 are shown in fig. 1, in which the flaky crystals are randomly staggered instead of being regularly stacked.
The molecular sieve of example 1 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 38.6% and a selectivity of over 90%.
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, 13.9 g 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 solid product is obtained by filtering, washing and drying, and XRD detection results show that the solid product contains a large amount of amorphous substances besides ZSM-35 molecular sieve, and the relative crystallinity is set as 100. The molecular sieve has a molar ratio of silicon to aluminum of 19 and an average thickness of 200nm.
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 molecular sieve of comparative example 1 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 23.6% and a selectivity of about 54%.
Comparative example 2
(1) 1.233 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.72 g of potassium hydroxide and 10.42 g of ethylenediamine 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 10 hours at 65 ℃ 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 to obtain 8.4 g of solid product, and the detection result shows that the solid product is a prismatic molecular sieve with FER structure, the average thickness of a sheet layer is 300 nanometers, the relative crystallinity is 142, and the silicon-aluminum ratio is 21.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝31；SDA2/SiO 2 ＝1.1；OH - SiO 2 ＝0.08；H 2 O/SiO 2 ＝19。
SEM photograph of the molecular sieve having FER structure prepared in comparative example 2 is shown in fig. 2.
The molecular sieve of comparative example 2 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 30.4% and a selectivity of about 69%.
Comparative example 3
(1) Dissolving 0.770 g of sodium aluminate, 0.08 g of sodium hydroxide and 0.72 g of potassium hydroxide in 39 g of deionized water, adding 4.10 g of 1, 3-dimethylimidazole ionic liquid chloride, adding 0.6 g of ZSM-35 molecular sieve seed crystal, and aging for 10 hours at 65 ℃ to obtain a mixture A;
(2) 7.42 g of ethylenediamine is added with stirring;
(3) 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;
(4) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 175 ℃ for 40 hours. After crystallization, 7.8 g of solid product is obtained through filtration, washing and drying, and the detection result shows that the solid product is a molecular sieve nano-sheet with a FER structure, the relative crystallinity is 121, the silicon-aluminum ratio is 46, and the average thickness of the sheet layer is 180 nanometers.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝50；SDA1/SiO 2 ＝0.2；SDA2/SiO 2 ＝0.8；OH - /SiO 2 ＝0.08；H 2 O/SiO 2 ＝19。
the molecular sieve of comparative example 3 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 30.8% and a selectivity of about 55%.
Example 2
(1) 3.699 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.72 g of potassium hydroxide and 11.73 g of imidazole are dissolved in 39 g of deionized water, 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) 5.57 g of ethylenediamine is added with stirring;
(3) 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;
(4) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 160 ℃ for 60 hours. After crystallization, filtering, washing and drying are carried out, thus obtaining 11.5 g of solid product. The detection result shows that the solid product is molecular sieve nano-sheets with FER structure, the relative crystallinity is 170, the silicon-aluminum ratio is 15, the average thickness of the sheets is 30 nanometers, and the sheet 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 ＝10；SDA1/SiO 2 ＝1.1；SDA2/SiO 2 ＝0.6；OH - /SiO 2 ＝0.08；H 2 O/SiO 2 ＝19。
the molecular sieve of example 2 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 39.2% and a selectivity of about 87%.
Example 3
(1) Dissolving 0.142 g of sodium aluminate, 2.92 g of sodium hydroxide and 13.6 g of imidazole in 22 g of deionized water, adding 0.6 g of ZSM-35 molecular sieve seed crystal, and aging for 6 hours at 70 ℃ to obtain a mixture A;
(2) 14.6 g of n-butylamine is added with stirring, and then stirring is continued for half an hour, and 4.2 g of NaF is added;
(3) Slowly adding 30 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 13;
(4) 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, thus obtaining 12.1 g of solid product. The detection result shows that the solid product is molecular sieve nano-sheets with FER structure, the relative crystallinity is 165, the silicon-aluminum ratio is 268, the average thickness of the sheets is 15 nanometers, and the sheet 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 ＝350；SDA1/SiO 2 ＝1.0；SDA2/SiO 2 ＝1.0；F - /SiO 2 ＝0.5 OH - /SiO 2 ＝0.35；H 2 O/SiO 2 ＝11。
the molecular sieve of example 3 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 38.4% and a selectivity of about 89%.
Example 4
(1) 0.770 g of sodium aluminate, 1.24 g of sodium hydroxide, 0.584 g of potassium hydroxide and 11.41 g of 2-methylimidazole are dissolved in 52.89 g of deionized water, 0.186 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 2 hours at 80 ℃ to obtain a mixture A;
(2) 5.57 g of ethylenediamine is added with stirring;
(3) 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 13;
(4) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 145 ℃ for 96 hours. After crystallization, filtering, washing and drying are carried out, thus obtaining 11.5 g of solid product. The detection result shows that the solid product is molecular sieve nano-sheets with FER structure, the relative crystallinity is 145, the silicon-aluminum ratio is 43, the average thickness of the sheets is 145 nanometers, and the sheet crystals are randomly staggered but not stacked together regularly.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝50；SDA1/SiO 2 ＝0.9；SDA2/SiO 2 ＝0.6；OH - /SiO 2 ＝0.22；H 2 O/SiO 2 ＝24。
the molecular sieve of example 4 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 37.2% and a selectivity of about 86%.
Example 5
(1) 0.415 g of sodium aluminate, 2.92 g of sodium hydroxide and 5.76 g of 2, 4-dimethyl imidazole are dissolved in 46.8 g of deionized water, 1.3 g of ZSM-5 molecular sieve seed crystal is added, and the mixture is aged for 4 hours at 70 ℃ to obtain a mixture A;
(2) 11.88 g of cyclohexylamine was added with stirring, and stirring was continued for half an hour, with 2.52 g of NaF;
(3) Slowly adding 30 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 13;
(4) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized for 45 hours at 175 ℃. After crystallization, filtering, washing and drying are carried out, thus obtaining 12.1 g of solid product. The detection result shows that the solid product is molecular sieve nano-sheets with FER structure, the relative crystallinity is 158, the silicon-aluminum ratio is 97, the average thickness of the sheets is 15 nanometers, and the sheet 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 ＝120；SDA1/SiO 2 ＝0.3；SDA2/SiO 2 ＝0.6；F - /SiO 2 ＝0.30 OH - /SiO 2 ＝0.35；H 2 O/SiO 2 ＝18。
the molecular sieve of example 5 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 37.6% and a selectivity of about 85%.
Example 6
(1) 2.62 g of sodium aluminate, 2.64 g of potassium hydroxide and 2.75 g of imidazole are dissolved in 108 g of deionized water, 0.6 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 3 hours at 72 ℃ to obtain a mixture A;
(2) 7.95 g of cyclohexylamine are added with stirring;
(3) Slowly adding 30 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;
(4) And (3) putting the obtained mixture B into a stainless steel reaction kettle with a polytetrafluoroethylene lining, crystallizing at 140 ℃ for 5 days, filtering, washing and drying after crystallization is completed, and obtaining 14.8 g of solid product. The detection result shows that the solid product is molecular sieve nano-sheets with FER structure, the relative crystallinity is 164, the silicon-aluminum ratio is 24, the average thickness of the sheets is 95 nanometers, and the sheet 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；SDA1/SiO 2 ＝0.2；SDA2/SiO 2 ＝0.4；OH - /SiO 2 ＝0.20；H 2 O/SiO 2 ＝35。
the molecular sieve of example 6 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 36.4% and a selectivity of about 87%.
Example 7
(1) 0.191 g of sodium aluminate, 2.92 g of sodium hydroxide and 6.8 g of imidazole are dissolved in 64.8 g of deionized water, 1.3 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 4 hours at 70 ℃ to obtain a mixture A;
(2) 5.9 g of cyclohexylamine was added with stirring, and stirring was continued for half an hour, with 0.084 g of NaF;
(3) Slowly adding 30 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 13;
(4) 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, thus obtaining 11.9 g of solid product. The detection result shows that the solid product is molecular sieve nano-sheets with FER structure, the relative crystallinity is 158, the silicon-aluminum ratio is 186, the average thickness of the sheets is 15 nanometers, and the sheet 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 ＝260；SDA1/SiO 2 ＝0.5；SDA2/SiO 2 ＝0.3；F - /SiO 2 ＝0.01 OH - /SiO 2 ＝0.35；H 2 O/SiO 2 ＝23。
the molecular sieve of example 7 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 37.1% and a selectivity of about 82%.
Example 8
(1) Dissolving 0.276 g of sodium aluminate, 1.25 g of sodium hydroxide and 10.88 g of imidazole in 64.8 g of deionized water, adding 1.3 g of ZSM-35 molecular sieve seed crystal, and aging for 3 hours at 75 ℃ to obtain a mixture A;
(2) 4.8 g of ethylenediamine is added with stirring, and then stirring is continued for half an hour, and 2.1 g of NaF is added;
(3) Slowly adding 30 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 13;
(4) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 170 ℃ for 55 hours. After crystallization, filtering, washing and drying are carried out, thus obtaining 12.4 g of solid product. The detection result shows that the solid product is molecular sieve nano-sheets with FER structure, the relative crystallinity is 156, the silicon-aluminum ratio is 137, the average thickness of the sheets is 60 nanometers, and the sheet 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 ＝180；SDA1/SiO 2 ＝0.8；SDA2/SiO 2 ＝0.4；F - /SiO 2 ＝0.25 OH - /SiO 2 ＝0.15；H 2 O/SiO 2 ＝23。
the molecular sieve of example 8 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 36.3% and a selectivity of about 83%.
Example 9
(1) 2.62 g of sodium aluminate, 2.64 g of potassium hydroxide and 3.88 g of 2, 4-dimethylimidazole are dissolved in 108 g of deionized water, 0.6 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 3.5 hours at 72 ℃ to obtain a mixture A;
(2) 7.95 g of cyclohexylamine are added with stirring;
(3) Slowly adding 30 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 13;
(4) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized for 7 days at 130 ℃. After crystallization, filtering, washing and drying are carried out, thus obtaining 14.7 g of solid product. The detection result shows that the solid product is molecular sieve nano-sheets with FER structure, the relative crystallinity is 164, the silicon-aluminum ratio is 28, the average thickness of the sheets is 86 nanometers, and the sheet 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；SDA1/SiO 2 ＝0.2；SDA2/SiO 2 ＝0.4；OH - /SiO 2 ＝0.20；H 2 O/SiO 2 ＝35。
the molecular sieve of example 9 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 35.7% and a selectivity of about 82%.
Example 10
(1) 2.96 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.72 g of potassium hydroxide and 3.40 g of N-propylimidazole are dissolved in 11.14 g of deionized water, 0.6 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 5 hours at 60 ℃ to obtain a mixture A;
(2) 13.26 g of ethylenediamine is added with stirring;
(3) 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;
(4) The obtained mixture B was put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized at 185 ℃ for 36 hours. After crystallization is completed, filtering, washing and drying are carried out to obtain 10.5 g of solid product, and detection results show that the solid product is molecular sieve nano-sheet with FER structure, the relative crystallinity is 159, the silicon-aluminum ratio is 9, and the average thickness of the sheet layer is 130 nanometers.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝13；SDA1/SiO 2 ＝0.2；SDA2/SiO 2 ＝1.4；OH - /SiO 2 ＝0.08；H 2 O/SiO 2 ＝9。
the molecular sieve of example 10 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 36.4% and a selectivity of about 84%.
Example 11
(1) 0.770 g of sodium aluminate, 3.72 g of sodium hydroxide, 0.72 g of potassium hydroxide and 24.8 g of 1-n-butylimidazole are dissolved in 91.87 g of deionized water, 0.186 g of ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 2 days at 85 ℃ to obtain a mixture A;
(2) Adding 0.37 g of ethylenediamine while stirring;
(3) 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 13;
(4) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining, and crystallized for 7 days at 125 ℃. After crystallization, filtering, washing and drying are carried out, thus obtaining 9.8 g of solid product. The detection result shows that the solid product is molecular sieve nano-sheets with FER structure, the relative crystallinity is 145, the silicon-aluminum ratio is 43, the average thickness of the sheets is 86 nanometers, and the sheet crystals are randomly staggered but not stacked together regularly.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝50；SDA1/SiO 2 ＝1.3；SDA2/SiO 2 ＝0.04；OH - /SiO 2 ＝0.5；H 2 O/SiO 2 ＝38。
the molecular sieve of example 11 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 33.8% and a selectivity of about 79%.
Example 12
(1) 0.086 g sodium aluminate, 0.08 g sodium hydroxide, 0.72 g potassium hydroxide and 13.67 g 2, 4-dimethyl imidazole are dissolved in 11.14 g deionized water, then 1.48 g ZSM-35 molecular sieve seed crystal is added, and the mixture is aged for 18 hours at 50 ℃ to obtain a mixture A;
(2) 13.26 g of ethylenediamine is added with stirring, and then stirring is continued for half an hour, and 0.97 g of NaF is added;
(3) 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;
(4) The obtained mixture B is put into a stainless steel reaction kettle with polytetrafluoroethylene lining and crystallized for 8 days at 185 ℃. After crystallization is completed, 9.7 g of solid product is obtained by filtering, washing and drying, and the detection result shows that the solid product is a molecular sieve nano-sheet with a FER structure, the relative crystallinity is 121, the silicon-aluminum ratio is 376, and the average thickness of the sheet layer is 148 nanometers.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝450；SDA1/SiO 2 ＝0.9；SDA2/SiO 2 ＝1.4；F - /SiO 2 ＝0.15 OH - /SiO 2 ＝0.08；H 2 O/SiO 2 ＝9。
the molecular sieve of example 12 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 30.5% and a selectivity of about 74%.
Example 13
According to the method of example 1, except that 23.2 g of silica sol, 10.42 g of ethylenediamine, 1.233 g of sodium aluminate, 0.08 g of sodium hydroxide, 0.72 g of potassium hydroxide and 2.10 g of imidazole were dissolved in 39 g of deionized water, 0.6 g of ZSM-35 molecular sieve seed crystal was further added, aging was conducted at 65℃for 10 hours to obtain a mixture, and the obtained mixture B was charged into a stainless steel reaction vessel with a polytetrafluoroethylene liner and crystallized at 175℃for 40 hours.
The material ratio (molar ratio) of the reactants is as follows:
SiO 2 /Al 2 O 3 ＝31；SDA1/SiO 2 ＝0.2；SDA2/SiO 2 ＝1.1；OH - /SiO 2 ＝0.08；H 2 O/SiO 2 ＝19。
the molecular sieve of example 1 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 34.6% and a selectivity of 88%.
Example 14
The procedure of example 1 was followed except that SDA2 was a mixture of n-butylamine and ethylenediamine in a 1:1 molar ratio, with the total amount of SDA2 unchanged and the remaining conditions the same.
The molecular sieve of example 1 was tested for performance in the n-butene isomerization reaction with an isobutene yield of 43.8% and a selectivity of 94% or more.
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 (23)

1. A method for synthesizing a molecular sieve having a FER structure, comprising subjecting a mixture formed from a raw material containing a silicon source, an aluminum source, an alkali source, a first template SDA1, a second template SDA2, and water to crystallization treatment, wherein the first template is selected from imidazole and/or C1-C4 alkyl-substituted imidazole, and the second template is different from the first template; the molar ratio of the first template agent to the second template agent is SDA 1/SDA2=0.05-10; in the mixture, siO is used as 2 Silicon source, in Al 2 O 3 Aluminium source in terms of OH - The calculated molar composition of the alkali source, the template agent and the water is as follows: siO (SiO) 2 /Al 2 O 3 5 to 500; SDA1/SiO 2 0.01 to 1.5; SDA2/SiO 2 0.01 to 1.5; OH (OH) - /SiO 2 0.01 to 0.50; h 2 O/SiO 2 9 to 40.
2. The method of claim 1, wherein,
the mixture contains seed crystals, and the molar ratio of the seed crystals to a silicon source is 1-20:100 in terms of silicon dioxide; the seed crystal is selected from one or more of ZSM-35 and ZSM-5.
3. The method of claim 2, wherein,
the mole ratio of the seed crystal to the silicon source is 3-15:100 based on silicon dioxide; the seed crystal is selected from ZSM-35 molecular sieve.
4. The method of claim 1, wherein,
the mixture contains a fluorine source, F - Gauge F - /SiO 2 0.005 to 0.50;
the fluorine source is selected from at least one of ammonium fluoride, sodium fluoride and potassium fluoride.
5. The method according to claims 1-4, wherein the method comprises:
(1) Aging a solution containing an aluminum source, a first template agent SDA1 and seed crystals at 40-99 ℃ to obtain a mixture A;
(2) Adding a second template agent SDA2 under stirring;
(3) Adding a silicon source under stirring to obtain a mixture B, and controlling the pH value of the mixture B to be more than 9;
(4) Crystallizing the obtained mixture B, and then performing solid-liquid separation and heat treatment;
wherein step (1) and/or step (2) and/or step (3) and/or step (4) are performed in the presence of an alkaline source.
6. The method of claim 5, wherein,
the aging temperature is 50-85 ℃; and/or
Aging for 0.5-20h; and/or
And (3) adding a fluorine source in the step (2).
7. The method of claim 6, wherein,
the aging temperature is 65-78 ℃; and/or
Aging for 1-15h; and/or
And (3) adding a fluorine source in the step (2).
8. The method of claim 1, wherein,
in the mixture, siO is used as 2 Silicon source, in Al 2 O 3 Aluminium source in terms of OH - The calculated molar composition of the alkali source, the template agent and the water is as follows: siO (SiO) 2 /Al 2 O 3 10 to 400; SDA1/SiO 2 0.05 to 1.2; SDA2/SiO 2 0.05 to 1.2; OH (OH) - /SiO 2 0.05 to 0.40; h 2 O/SiO 2 10 to 36.
9. The method according to any one of claims 1 to 4, wherein,
the silicon source comprises at least one of silica gel, silica sol, and tetraalkyl silicate.
10. The method according to any one of claims 1 to 4, wherein,
the aluminum source includes at least one of sodium aluminate, aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum hydroxide, and aluminum isopropoxide.
11. The method of any one of claims 1-4, wherein the first template SDA1 is at least one of imidazole, N-ethylimidazole, N-propylimidazole, 1-N-butylimidazole, 2-methylimidazole, 4-methylimidazole, 1, 2-dimethylimidazole, and 2, 4-dimethylimidazole.
12. The method of claim 11, wherein the first template SDA1 is imidazole.
13. The method according to any one of claims 1-4, wherein the second template SDA2 is at least one of ethylenediamine, n-butylamine, cyclohexylamine, piperidine, and pyridine.
14. The process of claim 13, wherein the second templating agent is one or more of ethylenediamine, n-butylamine, and cyclohexylamine.
15. The process of claim 14, wherein the second templating agent is at least two of ethylenediamine, n-butylamine, and cyclohexylamine.
16. The preparation method according to claim 1, wherein the molar ratio of the first template to the second template is SDA 1/sda2=0.1 to 4.
17. The method of claim 16, wherein the molar ratio of the first template to the second template is SDA 1/sda2=0.2-3.
18. The process according to any one of claim 1 to 4, wherein,
the crystallization conditions include:
the crystallization temperature is 120-190 ℃; and/or
The crystallization time is 10 hours to 10 days.
19. The process according to claim 18, wherein,
the crystallization conditions include:
the crystallization temperature is 130-180 ℃; and/or
The crystallization time is 1-7 days.
20. A molecular sieve synthesized by the method of any one of claims 1-19.
21. The molecular sieve of claim 20, wherein the molecular sieve is nanoplatelet-shaped with a crystal thickness of 10-150nm.
22. The molecular sieve of claim 20, wherein the molecular sieve crystals have a thickness of 15-120nm.
23. Use of the molecular sieve of any of claims 20-22 in the field of isomerization reactions.
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