CN113620311B - ZSM-5 zeolite, and preparation method and application thereof - Google Patents

ZSM-5 zeolite, and preparation method and application thereof Download PDF

Info

Publication number
CN113620311B
CN113620311B CN202110737528.7A CN202110737528A CN113620311B CN 113620311 B CN113620311 B CN 113620311B CN 202110737528 A CN202110737528 A CN 202110737528A CN 113620311 B CN113620311 B CN 113620311B
Authority
CN
China
Prior art keywords
zeolite
zsm
catalyst
solution
aluminum
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110737528.7A
Other languages
Chinese (zh)
Other versions
CN113620311A (en
Inventor
杨世和
洪梅
董磊
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Peking University Shenzhen Graduate School
Original Assignee
Peking University Shenzhen Graduate School
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Peking University Shenzhen Graduate School filed Critical Peking University Shenzhen Graduate School
Priority to CN202110737528.7A priority Critical patent/CN113620311B/en
Publication of CN113620311A publication Critical patent/CN113620311A/en
Application granted granted Critical
Publication of CN113620311B publication Critical patent/CN113620311B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • C01B39/36—Pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11
    • C01B39/38—Type ZSM-5
    • C01B39/40—Type ZSM-5 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
    • B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, 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
    • 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
    • B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
    • B01J29/405—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively containing rare earth elements, titanium, zirconium, hafnium, zinc, cadmium, mercury, gallium, indium, thallium, tin or lead
    • 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
    • B01J35/39—Photocatalytic properties
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
    • C07C1/20—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon starting from organic compounds containing only oxygen atoms as heteroatoms
    • 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
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/10—After treatment, characterised by the effect to be obtained
    • B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
    • B01J2229/186—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself not in framework positions
    • 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
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/80—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70
    • C01P2002/82—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70 by IR- or Raman-data
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/80—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70
    • C01P2002/86—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70 by NMR- or ESR-data
    • 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
    • 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
    • C01P2004/04—Particle morphology depicted by an image obtained by TEM, STEM, STM or AFM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/30—Particle morphology extending in three dimensions
    • C01P2004/32—Spheres
    • 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
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2529/00—Catalysts comprising molecular sieves
    • C07C2529/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites, pillared clays
    • C07C2529/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • C07C2529/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Catalysts (AREA)
  • Silicates, Zeolites, And Molecular Sieves (AREA)

Abstract

The invention provides a ZSM-5 zeolite and a preparation method thereof, and provides an application of the ZSM-5 zeolite as a chemical reaction catalyst or a catalyst carrier. The invention has the advantages of simple raw materials, low price, easy obtainment, good compatibility with zeolite crystals, no damage to the zeolite crystals, flexible regulation and control of the zeolite crystallization process, change of the crystallization behavior of the zeolite, improvement of the crystallinity of the zeolite, improvement of the framework silica-alumina ratio, reduction of framework defects, improvement of the activity and stability of the catalyst, contribution to catalytic reaction, simple preparation process and contribution to industrial scale production. In addition, the ZSM-5 zeolite prepared by the invention can also be used as a carrier material of a semiconductor composite material catalyst, has extremely high compatibility and improves the photocatalytic reaction efficiency.

Description

ZSM-5 zeolite, and preparation method and application thereof
Technical Field
The invention belongs to the technical field of catalyst preparation, and particularly relates to ZSM-5 zeolite and a preparation method and application thereof.
Background
The ZSM-5 zeolite catalyst is a catalyst for catalyzing the reaction of preparing propylene from methanol, but because the natural microporous ZSM-5 zeolite is not beneficial to macromolecular diffusion due to smaller micropore size, the problem of serious diffusion limitation is caused, and meanwhile, the intrinsic structure of the zeolite catalyst has poorer catalytic performance, so the structure of the zeolite needs to be optimized and improved.
Since zeolite materials have great application potential in the fields of energy and health, it is very important to reasonably design and synthesize zeolite molecular sieves with target structures and properties. Although researchers have put great efforts on the controllable preparation of zeolite, including the adjustment of crystallization parameters and the use of some hard and soft templates, the crystallization mechanism is still poorly understood, and the rational control of nucleation and growth in the crystallization process of zeolite remains a great challenge. The prior zeolite crystallization theory is mainly divided into a classical crystallization theory and a non-classical crystallization theory, wherein the two theories are based on the addition process of nutrients, and the difference is that the nutrients in the classical crystallization theory are monomers of precursors, and the nutrients in the non-classical crystallization theory are oligomers, compounds, nanoparticles and the like of the precursors.
In the prior art, in order to realize the regulation and control of the specific functions of the microporous zeolite, the post-treatment method is greatly developed. In these post-treatment strategies, the use of high temperature steam, acid-base etching or hydrogen peroxide and microwave radiation to remove framework elements is often devastating to the structure of the zeolitic material, which can lead to the creation of secondary channels and the collapse of part of the framework structure, thereby reducing its crystallinity. The post-treatment methods commonly used in the prior art at present include: steam treatment, acid treatment, desilication.
The steam treatment process is a hydrothermal treatment process, and generally needs to be carried out at a temperature of 500 ℃ or higher, and Si-O-Al bonds in zeolite are broken, resulting in loss of aluminum from the zeolite framework to prepare a secondary pore structure. While the healing process, where some less stable and mobile silicon may migrate from elsewhere and condense with silanol at the defect, may result in a more complex hierarchical pore structure. Van Bokhoven et Al, using X-ray diffraction (XRD) and X-ray absorption Spectroscopy (XAS) in situ tests, found that steam-induced structural changes did not occur at the highest temperatures, water entered the pores at lower temperatures, when the frame Al was present 3+ Migration to a position outside the frame is also most evident. And typically a mild acid treatment may be required after the steam treatment. According to this mechanism, the formation of mesopores is highly dependent on the Al concentration in the zeolite and the degree of hydrolysis of Al sites. Therefore, most of the steaming work is carried out on zeolites having a low initial Si/Al ratio.
Acid treatment is also a commonly used dealumination process and the mechanism of secondary pore formation is the same as in steaming. Tromp et al performance tests in the hydroisomerization of n-hexane catalyzed by zeolite compared the activity of the acid-leached Pt/mordenite catalyst with the untreated Pt/mordenite catalyst; it was found that the activity of the acid-treated zeolite in the hydroisomerization of n-hexane was significantly increased, probably due to the reduction of the molecular diffusion path and the exposure of more acidic sites.
Desilication is also a method for preparing hierarchical pore zeolite molecular sieves, generally by means of an alkaline treatment. In 1967, young d.a. first synthesized mordenite which showed high crystallinity and had enhanced benzene adsorption capacity by treatment with a base.
Figure GDA0003302269590000021
Et al studied the framework element profile in the alkali treatment of ZSM-5 in detail. Ogura et al prepared for the first time ZSM-5 crystals with a mesoporous structure treated with sodium hydroxide. Groen et al subsequently explored in detail the alkaline treatment optimization conditions for mesopore formation; it has been found that for ZSM-5 crystals, the parent zeolite Si/Al ratio (50-100) is most suitable, producing zeolites with specific surface areas up to 235m 2 ·g -1 Meanwhile, the original crystallinity and acidity are kept; the mesopores produced are typically about 10nm with a relatively broad size distribution. When the Si/Al ratio is low, the formation of mesopores is limited by the repulsive force between OH "and the negatively charged lattice, whereas when the Si/Al ratio is high, more secondary pores are produced, but there is a severe loss of crystallinity. In addition to the Si/Al ratio, the morphology of the original zeolite (including large single crystals or intergrown small particles with large specific surface area) also has a strong influence on the dissolution process of desilication, where the boundaries and defect parts of the zeolite crystals are more easily dissolved and etched. Then, researchers introduced inorganic additives (e.g., al (OH)) during the desilication process 4- And Ga (OH) 4- ) Or organic additives such as tetrapropylammonium and tetrabutylammonium to adjust the secondary pore structure of the crystals. The studies by Perrez-Ramfirez et al show that the specific interaction of these additives with the zeolite surface under alkaline conditions provides protection against excessive dissolution of the zeolite, which enables the preparation of zeolites with smaller mesoporous structures. And by the zeolite retaining a better microporous structure than by standard alkali treatment, wherein the affinity of the additive to the zeolite surface is believed to play a key role. Studies on different USY and Beta zeolites (Si/Al = 15-385) have shown that highly effective additives are positively charged and have about 10-20 carbon atomsThe organic molecule of (2). The use of external additives allows to extend the process to all-silica zeolites and to prevent excessive desilication phenomena, maintaining to a certain extent the Si/Al ratio of the zeolite crystals.
In addition to the above methods, calcination and chemical treatment with ammonium hexafluorosilicate, silicon tetrachloride or ethylenediaminetetraacetic acid have also been reported as dealumination methods for producing a hierarchical pore zeolite. This approach has not solved the diffusion limitation problem of microporous zeolites because the number of acid sites in the zeolite is reduced during dealumination due to the removal of aluminum atoms from the framework and it has also been found that the zeolite prepared by dealumination contains many independent cavities rather than an interconnected pore structure.
Regarding crystallization control, the current zeolite crystallization theory is mainly divided into a classical crystallization theory and a non-classical crystallization theory, and the two theories are based on the addition process of nutrients, and the difference is that the nutrients in the classical crystallization theory are monomers of precursors, and the nutrients in the non-classical crystallization theory are oligomers, compounds, nanoparticles and the like of the precursors. The specific mechanism of action of these crystallization mechanisms is unclear and is not flexible to control in terms of zeolite structure and physicochemical properties. In addition, the zeolite with a core-shell structure can be synthesized by a crystal inverse growth theory which appears recently, but a plurality of additives are required to be added in the synthesis process, the synthesis steps are complicated, and the repeatability is poor.
Aluminosilicate zeolites, on the other hand, are effective supports for semiconductor photocatalysts and are commonly used to remove organic compounds from wastewater and air. The dispersing action of the aluminosilicate zeolite not only inhibits the growth and aggregation of the crystallite size of the semiconductor particles, but also facilitates the separation and recovery of the photocatalyst from the bulk medium. The zeolite carrier can be used as an adsorbent to pre-adsorb and condense organic compounds on the surface of the catalyst, which is beneficial to promoting the photocatalytic activity. The improvement of the photocatalytic performance of zeolite-based composite materials is mainly determined by the enhanced adsorption performance and the separation and transfer efficiency of photogenerated carriers. However, the existing zeolite carrier has the defects of low specific surface area, limited accessible catalytic sites, poor compatibility with semiconductor materials and the like.
Therefore, it is highly desirable to provide a zeolite catalyst with excellent catalytic performance, which is prepared by a simple preparation process, improves the crystallinity of zeolite, changes the framework silica-alumina ratio of zeolite, and optimizes the acid sites of zeolite, and is used as a carrier of a composite catalytic material.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides the following technical scheme:
the first aspect of the present invention provides a method for preparing a ZSM-5 zeolite, comprising the steps of:
s1: according to the weight percentage of an aluminum source: silicon source: quaternary ammonium cation templating agent: organic small molecule compound containing active hydrogen: the water molar ratio is (0.1-0.5): (1-10): (0.15-3): (0 to 3.5): (50-1000), slowly dissolving raw materials, namely an aluminum source, a silicon source, a quaternary ammonium cation template agent and an organic micromolecular compound containing active hydrogen, in deionized water, and continuously stirring until a synthetic solution is formed;
s2: aging the synthetic liquid for 1-5 days at room temperature to obtain an aged liquid, crystallizing the aged liquid at 100-200 ℃ for 24-72 hours, centrifugally washing for 2-4 times after crystallization is finished, and drying at 50-70 ℃ overnight to obtain a dried substance; preferably, the aging time is 2 days; preferably, the aging temperature is 0-30 ℃; preferably, the crystallization time is 120-170 ℃; preferably, the centrifugal water washing times are 3; preferably, the drying temperature is 60 ℃;
s3: calcining the dried substance obtained in the step S2 at 500-800 ℃ for 4-8 h to obtain the catalyst; preferably, the calcination temperature is 550 ℃; preferably, the calcination time is 6h;
further, S1 specifically includes:
s11: according to the aluminum source: silicon source: quaternary ammonium cation templating agent: organic small molecule compound containing active hydrogen: the water molar ratio is 0.1:10:3: (0 to 3.5): weighing the raw materials according to the proportion of 1000;
s12: uniformly mixing an aluminum source and a silicon source to obtain stock solution;
s13: dissolving a quaternary ammonium cation template and an organic micromolecular compound containing active hydrogen in deionized water, and continuously stirring until a solution is formed;
s14: slowly adding the stock solution prepared in the step S12 into the solution prepared in the step S13 while stirring, and uniformly mixing to obtain a synthetic solution;
or further, the S1 specifically includes:
s11: according to the aluminum source: silicon source: quaternary ammonium cation templating agent: organic small molecule compound containing active hydrogen: the water molar ratio is 0.1:10:3: (0 to 3.5): weighing raw materials in a proportion of 1000;
s12: adding an aluminum source, a quaternary ammonium cation template and an organic small molecular compound containing active hydrogen into deionized water under continuous stirring until the aluminum source, the quaternary ammonium cation template and the organic small molecular compound are completely dissolved to form a solution;
s13: slowly adding the silicon source solution into the solution formed in the step S21 while stirring vigorously to form a synthetic solution;
further, in S1, the aluminum source is selected from aluminum isopropoxide and Al 2 (SO 4 ) 3 Any one or more of pseudo-boehmite, aluminum sec-butoxide, aluminum hydroxide, aluminum oxide and aluminum simple substance; preferably, the aluminum source is aluminum tri-sec-butoxide or Al 2 (SO 4 ) 3 ；
Further, in S1, the silicon source is selected from SiO containing 20-60% of effective substances by mass 2 Any one or more of sol, gas-phase silicon dioxide, sodium silicate and ethyl orthosilicate; preferably, the silicon source is sodium silicate or ethyl orthosilicate;
further, in the step S1, the quaternary ammonium cation template is a tetrapropylammonium hydroxide (i.e., TPAOH) aqueous solution with a mass percentage concentration of 10% to 40%; preferably, the mass concentration of the tetrapropylammonium hydroxide (i.e. TPAOH) aqueous solution is 40%;
further, in S1, the organic small molecular compound containing active hydrogen is selected from any one or more of phenol, alanine, lysine, 1,2, 4-triazole, trifluoroacetic acid, isobutyric acid or derivatives thereof; preferably, the small molecular compound containing active hydrogen is phenol;
further, in S2, the crystallization is carried out in a polytetrafluoroethylene-lined stainless steel autoclave, the polytetrafluoroethylene-lined stainless steel autoclave is heated in a rotary oven, and the rotation speed of the oven is 10-30 rpm;
the second aspect of the invention provides a ZSM-5 zeolite prepared by the above method;
further, the ZSM-5 zeolite has an oval shape, the particle size of the zeolite is 2-3 mu m, and the molar weight ratio of the elements is silicon: aluminum is 50-150: 1; the inner diameter of the inner mesopore is 8-20 nm; preferably, the molar ratio of the elements silicon: the aluminum accounts for 80-140: 1; preferably, the ZSM-5 zeolite has a mesopore inner diameter of 10nm;
a third aspect of the invention provides the use of a ZSM-5 zeolite as described above as a catalyst or catalyst support;
further, the catalyst is used in the reaction of preparing propylene from methanol;
or further, the carrier used as the catalyst is used as a carrier for preparing the composite semiconductor photocatalyst; further, the preparation of the composite semiconductor photocatalyst comprises the following steps:
mixing n-butyl titanate, ethanol and nitric acid according to the volume ratio of 5-8 2 Accounting for 5-50% of the ZSM-5.
Drawings
FIG. 1 is an evolution diagram of the etched time-varying structure of the crystal growth behavior of the ZSM-5 zeolite of example 1
FIG. 2 is a graph of the crystal crystallization time correlation spectrum of the ZSM-5 zeolite of example 1
FIG. 3 is a graph of the size, composition and crystallinity of the ZSM-5 zeolite of example 1
FIG. 4 is a schematic diagram illustrating the mesoporous characteristics of ZSM-5 zeolite in example 1
FIG. 5 shows the reaction of the catalytic performance of ZSM-5 zeolite prepared in example 1 and example 2 in MTP
FIG. 6 is a graph of the protocol and range study of nucleophilic etching growth in example 3
Advantageous effects
1. The organic micromolecule with active hydrogen contained in the raw material used by the invention has flexible and simple structure, low price and easy obtaining, good compatibility with zeolite crystal, no damage to the zeolite crystal, flexible regulation and control on the zeolite crystallization process, change of the crystallization behavior of the zeolite, further improve various physical and chemical properties of the zeolite, such as simultaneously improving the zeolite crystallinity, improving the framework silicon-aluminum ratio, enlarging the size and generating mesopores, the synthesized zeolite has a single crystal structure, the increase of the silicon-aluminum ratio is favorable for improving the catalyst stability, the acidity is moderate, and the catalytic reaction is favorable.
2. The synthesis method of the ZSM-5 zeolite is simple, convenient and feasible, low in synthesis temperature and low in cost. Because the reaction solution is not added with sodium hydroxide, ion exchange in the finished product is avoided; after calcination, the preparation cost of the catalyst is obviously reduced, and the preparation procedure of the zeolite is simplified.
3. Because the catalyst has larger size, the tablet can carry out catalytic reaction, the pressure drop is small, and the catalytic conversion number (TON) and the conversion frequency (TOF) are also very high.
4. The ZSM-5 zeolite is used as a semiconductor photocatalyst carrier, has high specific area, high stability, good compatibility with semiconductor materials, capability of effectively separating photon-generated carriers, strong adsorption affinity with degraded reactants and remarkably improved photocatalytic efficiency.
Detailed Description
1.1 Experimental materials
All reagents were commercially available and used without purification. Aluminum tri-sec-butoxide and 2-amino-1-propanol were purchased from Aldrich (Aldrich). Tetrapropylammonium hydroxide (40%), phenol, trifluoroacetic acid, L-lysine, isobutyric acid, 1H-1,2, 4-triazole were purchased from Hadamard (Adamas). Ethyl orthosilicate is purchased from Aladdin. Methanol was purchased from general purpose reagent (great).
1.2 examples
Example 1: synthesis of ZSM-5 zeolite-ethyl orthosilicate as silicon source
A preparation method of ZSM-5 zeolite comprises the following steps of S1-S2:
the S1 step comprises: s11: 0.16g of aluminum tri-sec-butoxide (C) 12 H 27 AlO 3 Molecular weight 246, purity (mass percent) 97%) and 6.97g of tetraethoxysilane (C) 8 H 20 O 4 Si with the molecular weight of 208) are uniformly mixed to be used as stock solutions of an aluminum source and a silicon source; s12: 5g of TPAOH (40% by weight aqueous TPAOH solution) and 0.9255g of phenol were dissolved in 56g of deionized water and continuously stirred until a solution was formed; s13: slowly adding the stock solution prepared in the step S11 into the solution prepared in the step S12 while stirring, and uniformly mixing to obtain a synthetic solution; s2: aging the synthetic liquid for 2 days at room temperature, after aging is finished, placing the synthetic liquid into a 100mL polytetrafluoroethylene-lined stainless steel high-pressure kettle, heating the polytetrafluoroethylene-lined stainless steel high-pressure kettle in a rotary oven, crystallizing at the rotating speed of 10rpm and the temperature of 120 ℃ for 36 hours, after the reaction is finished, washing the product by using centrifugal water for three times, and drying at the temperature of 60 ℃ overnight to obtain a dried product; s3: and calcining the dried substance obtained in the step S2 at 550 ℃ for 6 hours to remove TPAOH, thus obtaining the TPAOH.
EXAMPLE 2 Synthesis of ZSM-5 Zeolite sodium silicate as silicon source
A preparation method of ZSM-5 zeolite comprises the following steps:
the step S1 comprises the following steps: s11: adding Al to deionized water under continuous stirring 2 (SO 4 ) 3 0.45g, 5g TPAOH (40% by weight aqueous TPAOH solution) and 0.62g phenol until they completely dissolved to form a solution; s12: 15g of Na was added while vigorously stirring 2 SiO 3 (containing SiO) 2 26.5 percent by mass of Na 2 O accounts for 10.6 percent by mass) of the solution is slowly added into the solution of S11 to form a synthetic solution; s2: at room temperature, the mixture is heatedAging the synthetic liquid for 2 days, after the aging is finished, placing the synthetic liquid into a 100mL polytetrafluoroethylene-lined stainless steel high-pressure kettle, heating the polytetrafluoroethylene-lined stainless steel high-pressure kettle in a rotary oven, wherein the rotation speed of the oven is 30rpm, crystallizing at 170 ℃ for 72 hours, after the reaction is finished, centrifugally washing a product for three times, and drying at 60 ℃ overnight to obtain a dried product; s3: and calcining the dried substance obtained in the step S2 at 550 ℃ for 6 hours to obtain the catalyst.
Example 3
A preparation method of ZSM-5 zeolite comprises the following steps of S1-S2:
the S1 step comprises: s11: 0.16g of aluminum tri-sec-butoxide (C) 12 H 27 AlO 3 Molecular weight 246, purity (mass percent) 97%) and 6.97g of tetraethoxysilane (C) 8 H 20 O 4 Si with the molecular weight of 208) are uniformly mixed to be used as stock solutions of an aluminum source and a silicon source; s12: 5g of TPAOH (40% by weight aqueous TPAOH solution) and 0.58g of alanine were dissolved in 56g of deionized water and continuously stirred until a solution was formed; s13: slowly adding the stock solution prepared in the step S11 into the solution prepared in the step S12 while stirring, and uniformly mixing to obtain a synthetic solution; s2: aging the synthetic liquid for 2 days at room temperature, after aging is finished, placing the synthetic liquid into a 100mL polytetrafluoroethylene-lined stainless steel high-pressure kettle, heating the polytetrafluoroethylene-lined stainless steel high-pressure kettle in a rotary oven, crystallizing at the rotating speed of 10rpm and the temperature of 120 ℃ for 36 hours, after the reaction is finished, washing the product by using centrifugal water for three times, and drying at the temperature of 60 ℃ overnight to obtain a dried product; s3: and (3) calcining the dried substance obtained in the step (S2) at 550 ℃ for 6h to remove TPAOH, thus obtaining the TPAOH.
Example 4 ZSM-5 Zeolite-semiconductor composite
TiO 2 the/ZSM-5 composite semiconductor photocatalyst is prepared according to a sol-gel method. Mixing n-butyl titanate, ethanol and nitric acid in a volume ratio of 6Adsorbing the composite semiconductor photocatalyst on the surface of ZSM-5 particles to form gel, drying the gel at 100 ℃ for 12h to remove a solvent, washing the ZSM-5 particles for three times, and calcining the gel in a muffle furnace at 400 ℃ for 2h to obtain the composite semiconductor photocatalyst, wherein TiO in the composite semiconductor photocatalyst 2 Accounting for 40 percent of the ZSM-5 by mass.
Comparative example 1
A preparation method of ZSM-5 zeolite comprises the following steps of S1-S2:
the S1 step comprises: s11: 0.16g of aluminum tri-sec-butoxide (C) 12 H 27 AlO 3 Molecular weight 246, purity (mass percent) 97%) and 6.97g of tetraethoxysilane (C) 8 H 20 O 4 Si with the molecular weight of 208) are uniformly mixed to be used as stock solutions of an aluminum source and a silicon source; s12: 5g of TPAOH (40% by mass aqueous TPAOH solution) is dissolved in 56g of deionized water and continuously stirred until a solution is formed; s13: slowly adding the stock solution prepared in the step S11 into the solution prepared in the step S12 while stirring, and uniformly mixing to obtain a synthetic solution; s2: aging the synthetic liquid for 2 days at room temperature, after aging is finished, placing the synthetic liquid into a 100mL polytetrafluoroethylene-lined stainless steel high-pressure kettle, heating the polytetrafluoroethylene-lined stainless steel high-pressure kettle in a rotary oven, crystallizing at the rotating speed of 10rpm and the temperature of 120 ℃ for 36 hours, after the reaction is finished, washing the product by using centrifugal water for three times, and drying at the temperature of 60 ℃ overnight to obtain a dried product; s3: and calcining the dried substance obtained in the step S2 at 550 ℃ for 6 hours to remove TPAOH, thus obtaining the TPAOH.
1.3 Experimental example
Experimental example 1
XRD, SEM, TEM, IR spectrum, and surface emission were performed on the ZSM-5 zeolite synthesized in example 1, 27 Al and 29 si solid MAS nuclear magnetic resonance experiments reflect the in-situ etching in the zeolite crystallization process and show the crystallization process of nucleation-dissolution-recrystallization, and the results are as follows:
FIG. 1: the evolution diagram of the etched time-varying structure of the crystal growth behavior of the "example 1ZSM-5 zeolite": (a) Testing the XRD patterns of the zeolite obtained at different crystallization times (intercepting a sample before the crystallization time is 32 h); (b) normalizing the time distribution of crystallinity; (c-e) SEM images of solid samples at (c) 0h, (d) 4h, and (e) 24h with inset magnified views of individual particles; (f-h) TEM images of solid samples at (f) 0h, (g) 4h, and (h) 24h, magnified inset shows high resolution TEM images showing the expected lattice fringes of the zeolite.
FIG. 2: time dependent spectral plots. Demonstration of the etching Process in the crystallization of the ZSM-5 Zeolite of example 1 (a) the IR Spectroscopy, (b) 27 Al-MAS nuclear magnetic resonance spectroscopy in which the inset shows the variation of the half-peak width with time, (c) 29 Si-MAS NMR spectra, inset shows the change in Q4/(Q2 + Q3) with time.
FIG. 3: size, composition and crystallinity of "example 1ZSM-5 zeolite". The size, composition and crystallinity of the ZSM-5 zeolite are controlled by varying the amount of phenol in the synthesis mixture, (a) the XRD pattern for different molar amounts of phenol, (b) the silica to alumina ratio, (c) the crystal size, (d-i) SEM images.
FIG. 4: the mesoporosity of ZSM-5 was controlled by varying the molar amount of phenol in the synthesis mixture. (a) N is a radical of hydrogen 2 The adsorption-desorption isotherm and (b) the BJH pore size distribution chart show the structural properties of the ZSM-5 molecular sieve synthesized by different phenol dosages, when the feeding ratio of silicon material and phenol reaches 10SiO 2 When the Phe is 3, a mesoporous structure of about 10nm is generated; (c) a low resolution TEM image of the sample of example 1; (d) magnified TEM images are shown in box (c); (d) The inset therein is an electron diffraction image of selected areas, revealing the in situ etching during zeolite crystallization.
Experimental example 2 catalytic test of ZSM-5 zeolite for propylene (MTP) with methanol
The atmospheric pressure MTP catalytic performance of the ZSM-5 zeolite obtained in example 1 was evaluated using a quartz fixed bed reactor. The method comprises the following specific steps: first, 0.3g of a catalyst (20-40 mesh) was placed in the center of a quartz tube (8 mm inner diameter) and placed on a reaction apparatus. The nitrogen flow rate was set at 100mL/min, the reaction temperature was set at 472 ℃, and the starting material methanol (95 v/v%) was added to the reaction system by a peristaltic pump and vaporized at 150 ℃. The space velocity (WHSV) of the reaction was 11.56g MeOH g Catalyst and process for producing the same -1 h -1 . The reaction product was detected by a gas chromatograph equipped with an ion flame detector and an HP-PLOT Q column. The methanol conversion and propylene selectivity were calculated according to the area normalization method, with 80% conversion as the catalytic conversion end point. Has extremely long service life and high propylene selectivity at high space velocity (WHSV), and the calculated active site conversion number (TON) and conversion frequency (TOF) are 1.47 x 10 6 And 1.63X 10 4 h -1 。
FIG. 5 shows the catalytic performance of the zeolites prepared separately in examples 1 and 2 compared to comparative example 1 (without phenol) in MTP by (a) methanol conversion in MTP and (b) C 3 H 6 Selective reaction of (2). Reaction conditions are as follows: t =472 ℃ and WHSV =12g MeOH g Catalyst and process for preparing same -1 h -1 。
FIG. 6: nucleophilic etching growth mechanism and etchant species research: (a) The zeolite nucleation growth and the nucleophilic etching process compete with each other, (b) the expansion of ZSM-5 zeolite organic nucleophile: (b 1) various developed organic substances. In the boxes are the molecular structure (top), the pKa1 value (bottom left) and the abbreviation (bottom right), the solid boxes represent etchants with etching capability, while the dashed boxes represent organic molecules without etching capability; (b2) Alanine is added to control the crystal size of ZSM-5, and (b 3) alanine is added to control the mesopores of ZSM-5.
Experimental example 3 ZSM-5 Zeolite-semiconductor Material composite and photocatalysis
The ZSM-5 zeolite synthesized in the example 1 is compounded with the semiconductor material titanium oxide, and the advantage of the zeolite as a hierarchical pore solid acid carrier for synthesizing the photocatalyst is reflected. Composite photocatalyst TiO 2 ZSM-5 was prepared according to the sol-gel method. N-butyl titanate, ethanol and nitric acid were mixed at a volume ratio of 6. After stirring for an additional 1 hour, about 1mL of deionized water was slowly added to the mixture. The stirring speed was maintained at 60rpm, and the temperature was controlled at 70 ℃ to hydrolyze the butyl titanate to adsorb it on the surface of the ZSM-5 particles. After gel formation, the gel was dried at 100 ℃ for 12 hours to remove the solvent. After washing for three times, calcining for 2 hours in a muffle furnace at 400 ℃ to generate the composite photocatalyst. TiO using the composite photocatalyst 2 The research on the photocatalytic degradation of acetaminophen in aqueous solution by the/ZSM-5 material shows thatAt an initial acetaminophen concentration of 15mg/L and a low light intensity of 1mW/cm 2 In the case of 3 hours of light irradiation, the degradation rate of acetaminophen by the photocatalyst prepared using the zeolite of example 1 was 96.8%, whereas the degradation rate of acetaminophen by the photocatalyst prepared using the zeolite of comparative example 1 was only 79.4%.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (6)

1. A method for preparing ZSM-5 zeolite is characterized by comprising the following steps:
s1 comprises the following steps: s11: according to the aluminum source: silicon source: quaternary ammonium cation templating agent: organic small molecule compound containing active hydrogen: the water molar ratio is 0.1:10:3: (0 to 3.5): weighing raw materials in a proportion of 1000, wherein the aluminum source is selected from Al 2 (SO 4 ) 3 Or secondary butyl alcohol aluminum, the silicon source is selected from sodium silicate or ethyl orthosilicate, the quaternary ammonium cation template agent is tetrapropyl ammonium hydroxide (TPAOH) aqueous solution with the mass percentage concentration of 10% -40%, and the organic small molecular compound containing active hydrogen is selected from phenol, alanine or lysine;
s12: under the condition of continuous stirring, adding an aluminum source, a quaternary ammonium cation template and an organic small molecular compound containing active hydrogen into deionized water until the aluminum source, the quaternary ammonium cation template and the organic small molecular compound are completely dissolved to form a solution;
s13: slowly adding the silicon source solution into the solution formed in the step S12 while stirring vigorously to form a synthetic solution;
s2: aging the synthetic liquid at 0-30 ℃ for 1-5 days to obtain an aging liquid, crystallizing the aging liquid at 120-170 ℃ for 24-72 hours, centrifugally washing for 2-4 times after crystallization, and drying overnight at 50-70 ℃ to obtain a dried substance, wherein the crystallization is carried out in a polytetrafluoroethylene-lined stainless steel autoclave, the polytetrafluoroethylene-lined stainless steel autoclave is heated in a rotary oven, the rotation speed of the oven is 10-30 rpm, and the crystallization temperature is 120-170 ℃;
s3: and calcining the dried substance obtained in the step S2 at 500-800 ℃ for 4-8 h to obtain the catalyst.
2. A ZSM-5 zeolite, characterized by being prepared by the process of claim 1.
3. The ZSM-5 zeolite according to claim 2, wherein the ZSM-5 zeolite has an oval morphology with a particle size of 2 to 3 μm, and the ratio of the molar amount of the elements to silicon: aluminum is 50-150: 1; and the inner diameter of the inner mesopore is 8-20 nm.
4. Use of a ZSM-5 zeolite as claimed in any of claims 2 to 3 as a catalyst or catalyst support, wherein the catalyst is used in the reaction of methanol to propylene.
5. Use of the ZSM-5 zeolite as defined in any of claims 2 to 3 as a catalyst or catalyst support, wherein the ZSM-5 zeolite is used as a catalyst support for the preparation of composite semiconductor photocatalysts.
6. Use according to claim 5, wherein the preparation of the composite semiconductor photocatalyst comprises the steps of:
mixing n-butyl titanate, ethanol and nitric acid according to the volume ratio of 5-8Forming gel, drying at 90-110 ℃ for 10-15 h to remove the solvent, washing ZSM-5 particles with water, and calcining at 300-500 ℃ for 1-3 h to obtain the composite semiconductor photocatalyst, wherein TiO in the composite semiconductor photocatalyst 2 Accounting for 5-50% of the ZSM-5.
CN202110737528.7A 2021-06-30 2021-06-30 ZSM-5 zeolite, and preparation method and application thereof Active CN113620311B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110737528.7A CN113620311B (en) 2021-06-30 2021-06-30 ZSM-5 zeolite, and preparation method and application thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110737528.7A CN113620311B (en) 2021-06-30 2021-06-30 ZSM-5 zeolite, and preparation method and application thereof

Publications (2)

Publication Number Publication Date
CN113620311A CN113620311A (en) 2021-11-09
CN113620311B true CN113620311B (en) 2023-02-28

Family

ID=78378774

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110737528.7A Active CN113620311B (en) 2021-06-30 2021-06-30 ZSM-5 zeolite, and preparation method and application thereof

Country Status (1)

Country Link
CN (1) CN113620311B (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104098109A (en) * 2013-04-03 2014-10-15 中国石油天然气股份有限公司 Spherical ZSM-5 zeolite molecular sieve and preparation and application thereof

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104098109A (en) * 2013-04-03 2014-10-15 中国石油天然气股份有限公司 Spherical ZSM-5 zeolite molecular sieve and preparation and application thereof

Also Published As

Publication number Publication date
CN113620311A (en) 2021-11-09

Similar Documents

Publication Publication Date Title
Wang et al. Postsynthesis of mesoporous ZSM-5 zeolite by piperidine-assisted desilication and its superior catalytic properties in hydrocarbon cracking
RU2700052C2 (en) Method of producing molecular sieve
TWI490167B (en) Method of preparing zsm-5 zeolite using nanocrystalline zsm-5 seeds
Zhu et al. Postsynthesis of FAU-type stannosilicate as efficient heterogeneous catalyst for Baeyer-Villiger oxidation
US20080214882A1 (en) Acidic mesostructured aluminosilicates assembled from surfactant-mediated zeolite hydrolysis products
EP3640207A1 (en) Molecular sieve scm-15, synthesis method therefor and use thereof
WO2017148852A1 (en) Controlled alkaline treatments on molecular sieves
Van Miltenburg et al. Alkaline modification of MCM-22 to a 3D interconnected pore system and its application in toluene disproportionation and alkylation
Wang et al. Ultrafast synthesis of nanosized Ti-Beta as an efficient oxidation catalyst via a structural reconstruction method
Huang et al. Synthesis of high-performanced titanium silicalite-1 zeolite at very low usage of tetrapropyl ammonium hydroxide
Yue et al. Dry-gel synthesis of hierarchical TS-1 zeolite by using P123 and polyurethane foam as template
WO2008095264A2 (en) Zeolite materials and synthesis method thereof
Al-Ani et al. Synthesis of nanostructured catalysts by surfactant-templating of large-pore zeolites
RU2622300C2 (en) Zeolite materials, and manufacturing methods using alcenyiltriammonium compounds
Yuan et al. Synthesis of hierarchical beta zeolite by using a bifunctional cationic polymer and the improved catalytic performance
CN111285381A (en) Hydrothermal synthesis method of nano Sn-Beta molecular sieve aggregate
JP2020502023A (en) Synthesis of molecular sieve SSZ-41
Chaida-Chenni et al. Synthesis of mesoporous-zeolite materials using Beta zeolite nanoparticles as precursors and their catalytic performance in m-xylene isomerization and disproportionation
Cheong et al. Rapid synthesis of nanocrystalline zeolite W with hierarchical mesoporosity as an efficient solid basic catalyst for nitroaldol Henry reaction of vanillin with nitroethane
Nabavi et al. Stability of colloidal ZSM-5 catalysts synthesized in fluoride and hydroxide media
CN101269819B (en) Method of preparing ZSM-5 molecular sieve containing mesopore structure
Li et al. Facile synthesis of nanosized mordenite and beta zeolites with improved catalytic performance: non-surfactant diquaternary ammonium compounds as structure-directing agents
CN113620311B (en) ZSM-5 zeolite, and preparation method and application thereof
Liu et al. Fabrication of a core–shell MFI@ TON material and its enhanced catalytic performance for toluene alkylation
US11434140B2 (en) Hierarchical zeolites and preparation method therefor

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant