CN113976168A - Preparation method and application of mesoporous nano mordenite with different morphologies - Google Patents

Preparation method and application of mesoporous nano mordenite with different morphologies Download PDF

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CN113976168A
CN113976168A CN202111387369.9A CN202111387369A CN113976168A CN 113976168 A CN113976168 A CN 113976168A CN 202111387369 A CN202111387369 A CN 202111387369A CN 113976168 A CN113976168 A CN 113976168A
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directing agent
mordenite
molecular sieve
structure directing
nano mordenite
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赵小燕
冯晓博
陈�峰
曹景沛
张立云
苏畅
赵静平
姚乃瑜
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China University of Mining and Technology CUMT
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    • 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
    • B01J29/18—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type
    • B01J35/613—
    • B01J35/615—
    • B01J35/617—
    • B01J35/633—
    • B01J35/635—
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
    • B01J37/0018—Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat)
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/30—Ion-exchange
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    • 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
    • C01B39/26—Mordenite type
    • C01B39/265—Mordenite type using at least one organic template directing agent
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    • C07C67/00—Preparation of carboxylic acid esters
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    • 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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    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/12—Surface area
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/16—Pore diameter
    • C01P2006/17—Pore diameter distribution

Abstract

The invention discloses a preparation method and application of mesoporous nano mordenite with different morphologies, which comprises the following steps of sequentially mixing sodium hydroxide, an aluminum source, deionized water, a silicon source, a structure directing agent A and a structure directing agent B, stirring and aging to form sol, wherein the structure directing agent A is an organic amine structure directing agent, and the structure directing agent B is dimethyl octadecyl [3- (trimethoxy silicon base) propyl ] ammonium chloride; putting the sol into a high-pressure reaction kettle, sealing, performing crystallization reaction at 120-180 ℃ for 4-14 days, and performing suction filtration, washing, drying and roasting on a solid product obtained after crystallization to obtain the sodium mordenite molecular sieve; obtaining the hydrogen type nanometer mordenite molecular sieve with special morphology through ammonia exchange. The invention synthesizes the molecular sieve catalyst with proper mesopores and larger specific surface area by adjusting the silicon-aluminum ratio, the grain diameter and the shape of crystal grains of the nano mordenite through adjusting the amount of the added structure-directing agent, thereby prolonging the service life of the molecular sieve catalyst in the carbonylation process.

Description

Preparation method and application of mesoporous nano mordenite with different morphologies
Technical Field
The invention belongs to the field of catalysts, relates to preparation of mordenite molecular sieves, and particularly relates to a preparation method and application of mesoporous nano mordenite with different morphologies.
Background
Ethanol is an important chemical basic raw material, can be used as a fuel and a fuel oil additive, and research and improvement of the production technology of the ethanol are hot spots. The synthesis of dimethyl ether (DME) by using synthesis gas as a raw material, the carbonylation of DME to synthesize Methyl Acetate (MA), and the hydrogenation of MA to prepare ethanol is the most promising route for the industrial application. This synthetic route is currently subject to the activity of the DME carbonylation reaction. The dimethyl ether carbonylation reaction is carried out by using Mordenite (MOR), Ferrierite (FER) and heteropolyacid zeolite (HPAS). The MOR catalyst exhibits better catalytic activity in carbonylation reactions than FER and solid acid catalysts due to its unique crystal structure and acid stability.
The focus of the current research is to synthesize nano mordenite with micro/meso pores, and the pure microporous mordenite is not beneficial to the diffusion and mass transfer of macromolecular reaction participation, so that the reaction efficiency and the service life of the catalyst are reduced. Mesoporous catalysts exhibit excellent performance with their high reactant and product diffusivity. The synthesis strategy of the mesoporous mordenite mainly comprises three methods, namely a template-free method, an organic template guiding method and a post-treatment method. CN1837046A reports that mordenite is used as seed crystal and a method of staged crystallization is used to prepare the mordenite molecular sieve with nanometer level, but the method has complicated synthetic steps. Maleki et al report that ultrasonic irradiation is a particularly novel method (ultrason. Sonochem 2018, 460-464.) for preparing a hierarchical nano catalyst, and the synthesis conditions are harsh and not conducive to large-scale use. The mesoporous mordenite obtained by acid or alkali treatment such as S.K. Saxena improves the texture performance, shows higher acidity (appl.Surf.Sci.2017, 392384-. CN102718231A utilizes hexadecyl trimethyl p-methyl benzene sulfonic acid ammonium salt as a template agent to directly prepare the layered small-grain mordenite molecular sieve with hierarchical pores by a hydrothermal synthesis method, the template agent needs to be synthesized by itself, so that the preparation cost of the molecular sieve is high, the synthesis cost of the zeolite molecular sieve is greatly improved, and the environmental pollution is easily caused.
According to the results of the current literature and Chinese patent research, the method comprises the following steps: meanwhile, the synthesis of the nano mordenite with the special morphology and the hierarchical pore structure is not reported.
Disclosure of Invention
The invention aims to provide a preparation method and application of mesoporous nano mordenite with different morphologies, and nano mordenite with different special morphologies can be obtained by regulating and controlling a structure directing agent.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a preparation method of mesoporous nano mordenite with different morphologies comprises the following steps:
(1) dissolving sodium hydroxide and an aluminum source in deionized water, stirring at room temperature until the solution is clear, then adding a silicon source into the solution, continuously stirring for 0.5-2 hours until the solution is gelatinous, adding a structure directing agent A and a structure directing agent B into the gel, and stirring and aging to form sol; the mol ratio of each component in the sol calculated by the oxide thereof is SiO2：Na2O：Al2O3: water: structure directing agent a: structure directing agent B ═ 1: 0.3-0.7: 0.01-0.1: 20-200: 0.001 to 1: 0.005 to 1; the structure directing agent A is an organic amine structureThe structure directing agent B is dimethyl octadecyl [3- (trimethoxysilyl) propyl group]Ammonium chloride;
(2) putting the sol prepared in the step (1) into a high-pressure reaction kettle, sealing, reacting for 4-14 days at the temperature of 120-180 ℃ in a crystallization dynamic or static state, and roasting after the crystallization is finished to obtain a solid product, wherein the solid product is subjected to suction filtration, washing and drying to obtain a sodium nano mordenite molecular sieve;
(3) and (3) dispersing the sodium nano mordenite molecular sieve obtained in the step (2) into an ammonium salt solution for ammonia ion exchange, repeating the step for 2-3 times, and then performing suction filtration, drying and roasting to obtain the hydrogen nano mordenite molecular sieve with the special morphology.
Preferably, the silicon source in step (1) is one of column chromatography silica gel, gas phase silica sol, tetraethyl orthosilicate, silica sol or water glass.
Preferably, the aluminum source in step (1) is any one of aluminum isopropoxide, pseudo-boehmite, aluminum hydroxide, aluminum sulfate, aluminum nitrate, aluminum chloride, aluminum isopropoxide or sodium metaaluminate.
Preferably, the drying temperature in the step (2) is 100-120 ℃, and the time is 12 hours; the roasting temperature is 500-600 ℃, and the roasting time is 4-8 h.
Preferably, the ammonium salt in the step (3) is ammonium nitrate or ammonium chloride, the concentration of the ammonium salt solution is 0.5-1.5mol/L, and the ammonia exchange conditions are as follows: the exchange time is 2-4 h, the exchange temperature is 70-90 ℃, and the solid-to-liquid ratio of the sodium type molecular sieve to the ammonium salt solution is 1 (10-100) g/mL.
Preferably, the drying temperature in the step (3) is 100-120 ℃, and the time is 12 hours; the roasting temperature is 500-600 ℃, and the roasting time is 4-8 h.
Preferably, the organic amine structure directing agent in step (1) is selected from one or more of tetramethylammonium hydroxide, tetramethylammonium bromide, tetraethylammonium hydroxide, tetraethylammonium bromide, tetrapropylammonium hydroxide and tetrapropylammonium bromide.
The invention also provides the application of the nano mordenite prepared by the method in the reaction of synthesizing methyl acetate from dimethyl ether. The molar ratio of dimethyl ether to CO in the raw material is 1 (5-100),preferably 1 (5-50); the reaction temperature is 180-300 ℃, and the reaction pressure is 1-3 MPa; air space velocity of 1000-plus 5000h-1。
Compared with the prior art, the invention has the following beneficial effects:
1. the nano zeolite molecular sieve with special morphology is synthesized by a one-step method by using a dimethyl octadecyl [3- (trimethoxysilyl) propyl ] ammonium chloride template agent as a structure directing agent, and the structure directing agent is low in consumption, so that the synthesis cost is greatly reduced, and the environmental pollution is reduced.
2. The silicon-aluminum ratio, the grain diameter and the shape of crystal grains of the nano mordenite are adjusted by adjusting the amount of the structure-directing agent added into the synthesis system.
3. The synthesis cost is low, the synthesis process is simple, the environmental pollution is relatively low, and the method is suitable for industrial large-scale production.
4. Under the condition of ensuring a certain silicon-aluminum ratio, the nano mordenite molecular sieve with proper mesopores and larger specific surface area can be controlled and synthesized, the material transmission channel is enlarged, the diffusion resistance is greatly reduced, the formation of carbon deposition in the catalytic conversion process is reduced, and the service life of the mordenite molecular sieve in the carbonylation process is prolonged.
Drawings
Figure 1 is an XRD pattern of nano mordenite molecular sieves prepared in examples 1-4 of the present invention.
Figure 2 is a graph of the pore size distribution (BJH) of the nano mordenite molecular sieves prepared in examples 1-4 of the present invention.
FIG. 3 is a drawing showing the nitrogen isothermal adsorption of the mesoporous nano mordenite molecular sieves prepared in examples 1 to 4 of the present invention.
FIG. 4 is a scanning electron micrograph of a sample of the nano mordenite molecular sieve prepared in example 1 of the present invention.
FIG. 5 is a scanning electron micrograph of a sample of the nano mordenite molecular sieve prepared in example 2 of the present invention.
FIG. 6 is a scanning electron micrograph of a sample of the nano mordenite molecular sieve prepared in example 3 of the present invention.
FIG. 7 is a scanning electron micrograph of a sample of the nano mordenite molecular sieve prepared in example 4 of the present invention.
FIG. 8 is a scanning electron micrograph of a sample of the nano mordenite molecular sieve prepared in comparative example 1 of the present invention.
Figure 9 is a performance test result of the mordenite molecular sieves of example 3 and comparative example 2 of the present invention for the service life of the catalyst.
Detailed Description
The invention is described in further detail below with reference to the figures and specific examples.
Example 1
Adding 0.6667g sodium hydroxide (96 wt%) into 39.32g deionized water, magnetically stirring to obtain clear solution, adding 0.5247g sodium metaaluminate (98 wt%) into the above solution, stirring until the solid is completely dissolved, adding 16g alkaline silica sol (30 wt% SiO)2) Slowly dropwise added to the above solution, magnetically stirred at room temperature for 1h to gel-like, and then 2.0916g of tetraethylammonium hydroxide (25 wt% aqueous solution) and 0.005g of dimethyloctadecyl [3- (trimethoxysilyl) propyl group]Adding ammonium chloride (60 wt% methanol solution) as structure directing agent into the gel, stirring with strong magnetic force for 2 hr, mixing, and placing into hydrothermal kettle. Crystallizing for 240 hours in a rotary oven at the temperature of 140 ℃ and the rotating speed of 20 r/min, performing suction filtration after crystallization is completed, then washing the crystal to be neutral by deionized water, drying the obtained sample for 12 hours at the temperature of 110 ℃, and roasting for 6 hours at the temperature of 550 ℃ in the air atmosphere to obtain the sodium mordenite molecular sieve.
And (2) placing the sodium mordenite molecular sieve in a beaker, adding 1.0mol/L ammonium chloride solution into the beaker, carrying out ion exchange for 5 hours at the water bath temperature of 80 ℃, wherein the solid-to-liquid ratio of the sodium mordenite molecular sieve to the ammonium chloride solution is 1:10g/mL, and repeating the ion exchange once to ensure that the exchange is complete. And then drying at 110 ℃ for 12h, and roasting at 550 ℃ for 4h in an air atmosphere to obtain the hydrogen-type mordenite molecular sieve.
The obtained solid product is analyzed by X-ray powder diffraction to be a mordenite molecular sieve (shown in figure 1); the nitrogen isothermal adsorption result shows that the specific surface area of the sample is 483m2The mesoporous volume is 0.425mL/g, the mesoporous specific surface area is 72m2G, mesoporous pore size distributionIs between 3 and 7nm, and as can be seen from the figure, 0.005g of dimethyloctadecyl [3- (trimethoxysilyl) propyl ] group is used]The ammonium chloride can successfully synthesize the nano mordenite.
The scanning electron micrograph is shown in FIG. 4. The figure shows that the diameter of the sample particle is less than 50nm, and the appearance is the mesoporous nano mordenite with the accumulation shape of nano particles.
Example 2
The preparation conditions were the same as in example 1 except that dimethyloctadecyl [3- (trimethoxysilyl) propyl ] ammonium chloride was added in an amount of 1.3234g in mass.
The obtained solid product is analyzed by X-ray powder diffraction to be a mordenite molecular sieve (shown in figure 1); the nitrogen isothermal adsorption result shows that the specific surface area of the sample is 491m2The mesoporous volume is 0.447mL/g, and the mesoporous specific surface area is 84m2(iii)/g, the mesoporous size distribution is 3-8 nm, and it can be seen from the figure that 1.3234g of dimethyloctadecyl [3- (trimethoxysilyl) propyl group is used]The ammonium chloride can successfully synthesize the mesoporous mordenite molecular sieve.
The scanning electron micrograph is shown in FIG. 5. The graph shows that the maximum particle size of the sample is 200-300nm, the thickness is less than 10nm, and the morphology is a single-layer sheet-shaped nano mordenite molecular sieve.
Example 3
The preparation conditions were the same as in example 1 except that dimethyloctadecyl [3- (trimethoxysilyl) propyl ] ammonium chloride was added in an amount of 3.3081g in mass.
The obtained solid product is analyzed by X-ray powder diffraction to be a mordenite molecular sieve (shown in figure 1); the nitrogen isothermal adsorption result shows that the specific surface area of the sample is 516m2The mesoporous volume is 0.557mL/g, the mesoporous specific surface area is 112m2(iii)/g, the mesoporous size distribution is 3-8 nm, and it can be seen from the figure that 3.3081g of dimethyloctadecyl [3- (trimethoxysilyl) propyl group is used]The ammonium chloride can successfully synthesize the mesoporous mordenite molecular sieve.
The scanning electron micrograph is shown in FIG. 6. The maximum length of the sample is 200-500nm, the diameter is less than 10nm, and the sample is a needle-shaped nano mordenite molecular sieve.
Example 4
The preparation conditions were the same as in example 1 except that dimethyloctadecyl [3- (trimethoxysilyl) propyl ] ammonium chloride was added so as to obtain 6.6171g in mass.
The obtained solid product is analyzed by X-ray powder diffraction to be a mordenite molecular sieve (shown in figure 1); the result of nitrogen isothermal adsorption shows that the specific surface area of the sample is 558m2The mesoporous volume is 0.905mL/g, the mesoporous specific surface area is 97m2(iii) a mesoporous pore size distribution of 3 to 10nm, wherein 6.6171g of dimethyloctadecyl [3- (trimethoxysilyl) propyl group is used]The ammonium chloride can successfully synthesize the mesoporous mordenite molecular sieve.
The scanning electron micrograph is shown in FIG. 7. The graph shows that the sample has the particle size of about 200nm, the thickness of 20-30 nm and the shape of the nano mordenite molecular sieve which is net-shaped or cage-shaped.
Comparative example 1
The preparation conditions were the same as in example 1 except that dimethyloctadecyl [3- (trimethoxysilyl) propyl ] ammonium chloride was not added.
The scanning electron micrograph is shown in FIG. 8. The shape of the catalyst can be seen from the figure, which is mordenite formed by stacking nano particles.
By comparing the morphologies of the mordenite molecular sieves of examples 1 to 4 and comparative example 1, it can be seen that the mordenite molecular sieves with different morphologies can be obtained by adding different amounts of dimethyloctadecyl [3- (trimethoxysilyl) propyl ] ammonium chloride as a structure directing agent, which indicates that dimethyloctadecyl [3- (trimethoxysilyl) propyl ] ammonium chloride plays a crucial role in forming a special structure of the molecular sieve.
Comparative example 2
The method is characterized in that a commercial mordenite molecular sieve (the silicon-aluminum ratio is 15) is purchased from Yangzhou neutralization petrochemical company Limited, the particle size is between 6 and 20 mu m, and the specific surface area is 312m2The total pore volume is 0.188mL/g, only micropores exist, and the commercial mordenite molecular sieve is subjected to dimethyl ether carbonylation to prepare the ethylene-BAnd (4) testing the performance of the methyl ester.
Carbonylation performance tests were conducted on the mordenite molecular sieves of examples 1-4 and comparative example 2. Tabletting the prepared mordenite molecular sieve to obtain 40-60 mesh MOR molecular sieve, filling into a stainless steel tube type fixed bed reactor with an inner diameter of 8mm, and filling quartz cotton into two ends of a catalyst bed layer respectively. Introducing pure N with the flow rate of 30mL/min from one end2And treating at 300 deg.c and normal pressure for 4 hr for the purpose of eliminating adsorbed water from the molecular sieve. When the temperature is reduced to 200 ℃, cutting the gas into raw material gas, wherein the mixture ratio of the raw material gas is DME/Ar/CO 1/1.5/47.5, and the gas space velocity is 2800h-1The catalyst performance was evaluated at a reaction temperature of 493K and a reaction pressure of 1.5 MPa. The results are shown in Table 1.
TABLE 1 results of different amounts of dimethyloctadecyl [3- (trimethoxysilyl) propyl ] ammonium chloride MOR catalyzed carbonylation of dimethyl ether to methyl acetate
Figure BDA0003367517080000071
From table 1, it can be seen that: different amounts of dimethyl octadecyl [3- (trimethoxysilyl) propyl ] ammonium chloride is added as a structure directing agent to successfully synthesize the mordenite molecular sieve with the nano-grade different morphologies and the micropore-mesopore composite pore channel structure, which shows excellent catalytic performance far higher than that of the current commercial mordenite molecular sieve. The reason why the catalytic effect is excellent is that: the synthesized mordenite molecular sieves with different morphologies have extremely small particle size which is far smaller than the micron-sized mordenite molecular sieves commonly applied at present, and the transmission path of substances is shortened in the catalytic reaction process; the synthesized mordenite molecular sieves with different morphologies have larger specific surface area and pore volume, and the micropore-mesopore composite pore channel structure is more beneficial to mass transfer in a catalytic reaction, so that the substance diffusion rate is accelerated, and the accumulation rate of carbon deposition in the pore channel is reduced.
Catalyst life test
The mordenite molecular sieves of example 3 and comparative example 2 were subjected to performance tests for catalyst life. Reaction conditions are as follows: the mixture ratio of raw material gas is DME/Ar/CO 1/1.5/47.5, P1.5 MPa, T493K, gas flow rate: 20 mL/min.
As can be seen in figure 9, there is an induction period for DME carbonylation on both commercial and acicular morphology mordenite catalysts, both with increasing DME conversion and reaching a maximum and then decreasing. The induction period for commercial MOR was about 4h, reaching a maximum DME conversion of about 22% at 4h and a conversion drop below 10% at 10 h; the induction period of the needle-like morphology MOR is about 12 hours, the maximum conversion rate of DME is about 80% in the 12 th hour, and the conversion rate in the 30 th hour is reduced to below 30%. The synthesized acicular shape of the invention can prolong the induction period of the catalyst, the highest conversion rate of DME is improved by about 4 times compared with the commercial mordenite catalyst, the activity of the catalyst is greatly enhanced, meanwhile, the synthesized acicular shape mordenite has a unique mesoporous-microporous composite structure, which is more beneficial to the diffusion of substances in the pore channels, reduces the blockage of the pore channels of the catalyst by carbon deposition in the reaction process, greatly prolongs the service life of the catalyst, and the conversion rate of DME is still higher than the maximum conversion rate of the commercial mordenite catalyst at 30 h. Overall, the performance of the self-synthesized acicular morphology mordenite catalyst was far superior to the commercial mordenite catalyst.

Claims (8)

1. A preparation method of mesoporous nano mordenite with different morphologies is characterized by comprising the following steps:
(1) dissolving sodium hydroxide and an aluminum source in deionized water, stirring at room temperature until the solution is clear, then adding a silicon source into the solution, continuously stirring for 0.5-2 hours until the solution is gelatinous, adding a structure directing agent A and a structure directing agent B into the gel, and stirring and aging to form sol; the mol ratio of each component in the sol calculated by the oxide thereof is SiO2：Na2O：Al2O3: water: structure directing agent a: structure directing agent B ═ 1: 0.3-0.7: 0.01-0.1: 20-200: 0.001 to 1: 0.005 to 1; the structure directing agent A is an organic amine structure directing agent, and the structure directing agent B is dimethyl octadecyl [3- (trimethoxysilyl) propyl ] group]Chlorination ofAmmonium;
(2) putting the sol prepared in the step (1) into a high-pressure reaction kettle, sealing, and carrying out crystallization reaction at 120-180 ℃ for 4-14 days; after crystallization, the obtained solid product is filtered, washed to be neutral, dried and roasted to obtain the sodium nano mordenite molecular sieve;
(3) and (3) dispersing the sodium nano mordenite molecular sieve obtained in the step (2) into an ammonium salt solution for ammonia ion exchange, repeating the step for 2-3 times, and then performing suction filtration, drying and roasting to obtain the hydrogen nano mordenite molecular sieve with the special morphology.
2. The method for preparing mesoporous nano mordenite with different morphologies according to claim 1, wherein the silicon source in the step (1) is one of column chromatography silica gel, gas phase silica sol, tetraethyl orthosilicate, silica sol or water glass.
3. The method for preparing mesoporous nano mordenite with different morphologies as claimed in claim 1, wherein the aluminum source in step (1) is any one of aluminum isopropoxide, pseudo-boehmite, aluminum hydroxide, aluminum sulfate, aluminum nitrate, aluminum chloride, aluminum isopropoxide or sodium metaaluminate.
4. The preparation method of mesoporous nano mordenite with different morphologies according to claim 1, wherein the drying temperature in the step (2) is 100-120 ℃ and the time is 12 hours; the roasting temperature is 500-600 ℃, and the roasting time is 4-8 h.
5. The method for preparing mesoporous nano mordenite with different morphologies according to claim 1, wherein the ammonium salt in the step (3) is ammonium nitrate or ammonium chloride, the concentration of the ammonium salt solution is 0.5-1.5mol/L, and the ammonia exchange conditions are as follows: the exchange time is 2-4 h, the exchange temperature is 70-90 ℃, and the solid-to-liquid ratio of the sodium molecular sieve to the ammonium salt solution is 1: 10-100 g/mL.
6. The preparation method of mesoporous nano mordenite with different morphologies according to claim 1, wherein the drying temperature in the step (3) is 100-120 ℃ and the time is 12 hours; the roasting temperature is 500-600 ℃, and the roasting time is 4-8 h.
7. The method for preparing mesoporous nano mordenite with different morphologies according to claim 1, wherein the organic amine structure directing agent in step (1) is one or more selected from tetramethylammonium hydroxide, tetramethylammonium bromide, tetraethylammonium hydroxide, tetraethylammonium bromide, tetrapropylammonium hydroxide and tetrapropylammonium bromide.
8. Use of the mesoporous nano mordenite prepared by the method of any one of claims 1 to 7 in a reaction for synthesizing methyl acetate from dimethyl ether.
CN202111387369.9A 2021-11-22 2021-11-22 Preparation method and application of mesoporous nano mordenite with different morphologies Pending CN113976168A (en)

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