CN110282635A - A kind of synthetic method and its application of nano-sized ZSM-5 zeolite - Google Patents
A kind of synthetic method and its application of nano-sized ZSM-5 zeolite Download PDFInfo
- Publication number
- CN110282635A CN110282635A CN201910395327.6A CN201910395327A CN110282635A CN 110282635 A CN110282635 A CN 110282635A CN 201910395327 A CN201910395327 A CN 201910395327A CN 110282635 A CN110282635 A CN 110282635A
- Authority
- CN
- China
- Prior art keywords
- nano
- zeolite
- template
- sio
- silicon source
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- 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
- 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
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Nanotechnology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Composite Materials (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Physics & Mathematics (AREA)
- Inorganic Chemistry (AREA)
- Silicates, Zeolites, And Molecular Sieves (AREA)
Abstract
The invention discloses a kind of synthetic methods of nano-sized ZSM-5 zeolite, silicon source, silicon source, the pre-cooling of template low temperature, low temperature ingredient and low temperature are concentrated, then crystallization 24~72 hours under the conditions of 150~200 DEG C, and the product suspension convection drying after crystallization is separated and roast demoulding to get.The basic technical features of this method are the kinetic competition relationships adjusted in synthetic system between oligomeric sial species nucleation and autohemagglutination; this method has easy to operate; product crystal content is high, separates without washing, and can meet current technology equipment etc. and mention a little, be suitable for large-scale production；This method obtains being less than the narrow nano-sized ZSM-5 zeolite of 100nm, particle size distribution range.
Description
Technical field
The synthetic method in field more particularly to a kind of nano-sized ZSM-5 zeolite is synthesized the invention belongs to inorganic material and its is answered
With.
Background technique
Nano zeolite is short in addition to diffusion admittance, and the external surface area of super large can effectively improve the anti-carbon in catalysis reaction
Ability, therefore widely paid close attention in catalytic field.In addition, the characteristic of nanometer high dispersive have good optical property and
Quick adsorption/desorption ability makes it in photoelectric conversion, anti-corrosive paints, inorganic dyestuff, gas sensor, zeolite membrane, drug
The fields such as carrier show the application value of reality and potentiality.
ZSM-5 zeolite is to synthesize (US 3702886) for the first time in 1972 by U.S. Mobil, is widely used in being catalyzed
The chemical processes such as cracking, aromatisation, alkylation, disproportionation, with the increase of utilization of resources depth and range, nano-ZSM-5 is gradually
By industrial applications, such as in hexahydrotoluene cracking, hexadecane isomerization, Cumene cracking technique, relative to micron
The nano zeolite of grade, nano-ZSM-5 is since diffusion admittance is short, aperture ratio is high, active sites are close to degree height, Extra specific surface area
The advantages that product is high, shows better catalytic activity and catalytic stability.
Although in a larger sense, nano zeolite includes the condensate of nanocrystalline composition, and polymeric size can be big
In 100nm, but still there is bigger room for improvement in applying, the synthesizing mean of current published nano-sized ZSM-5 zeolite and
Implementation result summarizes such as table 1.
The synthesizing mean and implementation result of the current published nano-sized ZSM-5 zeolite of table 1
In the application, the partial size of zeolite decides absorption/desorption performance of zeolite to nano zeolite, and sized zeolite particles are smaller, inhales
It is faster to echo desorption rate, meanwhile, the partial size of zeolite also determines anti-coking deactivation when using as catalyst, zeolite
Partial size is smaller, and the external surface area that can be efficiently used is bigger, and appearance carbon ability is stronger, and resistance to deactivation is higher.In addition, working as granularity
After 100nm, nano zeolite will obviously embody with the physical property difference of (Asia) micron zeolite, these difference are before
It is not related in open source information.It is specific the difference is that: a, after sized zeolite particles are less than 100nm will be embodied bright
Aobvious colloidal nature, it is extremely difficult to carry out conventional solid-liquor separation, currently known centrifugal sedimentation separation, vacuum filtration separation, pressure
Filter, cross-flow separation, centrifugal filtration separation, flocculation separation can not all be competent at the separation of nano zeolite.Table 2 lists conventional separation
Means application limitation in nano zeolite separation process.And in most of open source information, synthesized zeolite still may be used
To take conventional vacuum filtration method to carry out solid-liquor separation, and the washing of zeolite is carried out based on this, speculate from this point, this
A little open source information sized zeolite particles produced are often the scale for being in (Asia) micron.
The conventional separation means application limitation in nano zeolite separation process of table 2
B, when zeolite particle size is less than 100nm hereinafter, apparent delustring can be embodied when X-ray diffraction tests (XRD)
Property, diffraction peak intensity obtained is naturally less than the diffraction peak intensity of micron order (or submicron order), therefore, it is impossible to public affairs
The XRD relative crystallinity known indicates the absolute content of nano zeolite in sintetics.In the aforementioned publication, XRD is opposite
Crystallinity is still the only resource to the statement of nano zeolite crystalline state.
The synthesis process of ZSM-5 zeolite can be stated simply are as follows: silicon source and silicon source mix in certain medium, are formed without fixed
Then under hydrothermal conditions the Alusil of type is initially formed the nucleus with MFI structure, nucleus absorbs the nutrient of surrounding later
Growth, there is dynamic equilibrium between the growth of nucleus and the formation of nucleus, in other words, the formation of nucleus and the life of nucleus
The long raw material in consumption polymer system simultaneously, nucleus is few, then the raw material in synthetic system just enriches, and nucleus tends to grow
And the product of greater particle size is obtained, and nucleus is more, and the raw material in synthetic system is just relatively poor, it is unfavorable for the growth of nucleus, thus
Obtain the product compared with small particle.Existing open source literature is that the ZSM-5 boiling for obtaining small particle is realized based on this theory mostly
Stone.Table 3 lists method and its technical principle involved in open source information.
The synthesizing mean and technical principle of the current published nano-ZSM-5 of table 3
From table 3 it can be seen that most of technological means is by the formation of control nucleus and nucleus in open source information
Competitive relation between growth realizes the purpose of synthesis nano zeolite.That is, nucleus is raw after control nucleus is formed
Long complexity, e.g., plus seed are the quantitative proportions by artificially changing nucleus, and segmentation crystallization is then by low temperature hand
Section, inhibits the growth rate of nucleus, to increase the quantity of nucleus；Improve the principle and segmentation crystallization of the alkalinity of synthetic system
It is similar；Addition surfactant or organic matter and (class) synthesis in solid state are then by improving sial species in conjunction with nucleus
Difficulty inhibits the growth of nucleus.
By inhibiting the growth of nucleus to have the defects that basic, i.e. nucleus to obtain the technical solution of small particle size zeolite
Inherently a kind of crystal of nanoscale in the environment full of raw material (sial species), and can not prevent completely nucleus
Growth.Therefore, the above-mentioned technical solution for taking control nucleus growth means, the partial size of product are often both greater than 100nm,
That is granularity of the product not less than nucleus.
Further, since technological means focuses on the competitive relation between the formation of control nucleus and nucleus growth, therefore, suddenly
It has omited during nucleus growth, the variation of sial species and the formation of secondary nucleus, leading to product is often nanocrystalline polymerization
Body or these polymeric partial sizes are greater than 100nm.
And other are to control sial species as technical characteristic, that is, control the open source information of the process before nucleus is formed,
Such as: the technical solution of CN 102602959A is by preparing a kind of active silicon source, and CN 102502696A is by acid, alkali tune
It saves to control the degree of polymerization of silicon species and aluminium species.But it generally requires to cooperate other technological means, be such as segmented crystallization or add
Add crystal seed etc., technical controlling difficulty is high, is unfavorable for industrial production, and product is often nanocrystalline condensate, size
Greater than 100nm.From this point forward, there is no processes before really effectively being formed to nucleus to realize effectively for these open source informations
Control, does not have practicability.
Zeolite is to be reacted in strong alkali solution by silicate and aluminate and crystallization forms, and the raw material most started is in alkali
The silicate ion and aluminate ion of different polymeric forms, these silicate ions and aluminate ion phase are formed in property environment
It mutually combines, forms initial more ring structures unit, these more ring structures are combined with each other assembly again, form nucleus, Zhi Houjing
Core be combined with each other with the more ring structures (nutriment) in solution, so that crystal growth.It is molten during this
Glue nucleation is committed step, and a large amount of nucleation will make to lack enough reactivity species and " nutritional ingredient " in reaction system
Supply crystal growth, to limit crystalline size, in addition, nucleation rate and rate of crystalline growth also determine zeolite partial size and
Distribution, to obtain superfine zeolite.Figure 15 is ZSM-5 zeolite crystallization process schematic diagram.
When the silicate ion (monomer and dimer) of oligomeric state is used as key reaction raw material, the activation of nucleus is formed
Can be minimum, it is easy to achieve the effect that largely to be nucleated.But the silicate ion spontaneous polymerization of oligomeric state forms the silicon of high poly- state
The trend of acid ion is also very strong, and forms competitive relation with nucleation process.In open source information, nearly all have ignored low
The competitive relation of polysilicon acid root nucleation and autohemagglutination.And by adjusting this competitive relation of oligomeric silicic acid root nucleation and autohemagglutination, change
Become the kinetics relationship of the two, to achieve the purpose that inhibit oligomeric silicic acid root autohemagglutination then simple and easy, is suitable for scale
Production requirement.
Summary of the invention
Definition:
Nano material: nano material refer in three dimensions at least one dimension be in nano-scale (0.1-100 nm) or
Material composed of them as basic units.Nano material in the present invention is to refer in particular to three dimensions all in nano-scale
Material in (0.1-100nm)；
Nano zeolite: nano zeolite refer in three dimensions at least one dimension be in nano-scale (0.1-100 nm) or
Zeolite composed of them as basic units, the present invention in nano material be to refer in particular to three dimensions all in nano-scale
Zeolite in (0.1-100nm)；
Particle: with the solid of specific shape in a size range；
Partial size: the granular size defined according to geometry size, partial size of the invention refer under electronic scanner microscope
What is observed determines direction maximum diameter；
Condensate: refer to secondary particle made of being reunited as unit grain (first stage particles)；
Crystalline content: refer to the mass percent of ZSM-5 crystalline solid in product, wt%.
In view of the problems of the above-mentioned prior art, the purpose of the present invention is to propose to a kind of synthesis of nano-sized ZSM-5 zeolite
Method and its application.
The purpose of the invention will be achieved through the following technical solutions:
A kind of synthetic method of nano-sized ZSM-5 zeolite, includes the following steps:
S1. it pre-processes: 4~48h is pre-chilled in silicon source, silicon source, template respectively, precooling temperature is -10~10 DEG C；
S2. it prepares: the silicon source after pre-cooling, silicon source, template being mixed evenly respectively, mixing temperature is -10~30
DEG C, obtain starting sol；
S3. it is concentrated: the colloidal sol being concentrated to give mixed sols while stirring, thickening temperature is 20~40 DEG C；
S4. by mixed sols, 12~72h of crystallization, crystallization temperature are 140~200 DEG C in high pressure crystallizing kettle, and it is outstanding to obtain product
Supernatant liquid；
S5. by 40~80 DEG C of dryings of product suspension, 350~600 DEG C of roasting Template removals obtain nano-ZSM-5 boiling
Stone.
Pre-cooling initial temperature of the invention is room temperature, and pre-cooling, which generallys use, stands cooling method, in order to improve pre-cooling effect
Rate, also in pre-cooling with whipping step.
The range of S4 crystallization time in the present invention is 12~72h, 36~60h of preferred scope；Crystallization temperature range is
140~200 DEG C, preferred scope is 160~180 DEG C, and static crystallization or stirring crystallization may be selected in crystal pattern, when crystallizing kettle public affairs
When volume being claimed to be less than 2L, static crystallization may be selected, when crystallizing kettle nominal volume is greater than 2L, selection stirring crystallization when crystallization.
The synthetic method of above-mentioned a kind of nano-sized ZSM-5 zeolite, wherein precooling temperature described in step S1 is -4~4
DEG C, mixing temperature described in step S2 is -4~15 DEG C, and thickening temperature described in step S3 is 30~35 DEG C, institute in step S5
Stating drying temperature is 40~60 DEG C, and the roasting calcining temperature is 300~400 DEG C.
Low temperature concentration is taken in known positive infiltration, reverse osmosis, ultrafiltration, pervaporation or reduction vaporization in the present invention
It is one or more, and technical parameter is determined according to the technological means taken.
In positive infiltration (also referred to as naturally osmotic) low temperature concentration technique, water or solvent throughout curve semi-permeable membrane are from water chemistry
The high region (Hyposmolality side) in position is spontaneously transmitted to the low region of aquation degree (hyperosmosis side), the driving of the process
Power is chemical potential difference or permeable pressure head, is not necessarily to impressed pressure or temperature.In this system, forward osmosis membrane material may be selected three
Cellulose acetate (CTA), polybenzimidazoles (PBI), polysulfones (PSF)/polyether sulfone (PES), drawing liquid is sodium chloride and/or chlorination
Magnesium aqueous solution, concentration is greater than 2.0mol/L, and when concentration, operating temperature range is 20~40 DEG C, and Hyposmolality lateral pressure range is
103~150kPa (A).
Reverse osmosis (also referred to as reverse osmosis) under the action of being higher than solution osmotic pressure, water or solvent can penetrate semi-permeable membrane (RO
Film) and other substances can not penetrate.The membrane aperture of reverse osmosis membrane can be effectively removed molten in water in Nano grade
Solve salt, colloid, microorganism, organic matter etc..According to chemical substance group constituent class, RO film can be divided into cellulose family film and non-fibre
Plain class film is tieed up, the former is mainly cellulose acetate film, and the latter then includes aromatic polyamides, Polysulfonamide, and polytetrafluoroethylene (PTFE) connects
Branch film, polyethyleneimine film etc..When being used for colloidal dispersion, acetate fiber tubular membrane may be selected as reverse osmosis membrane, colloidal sol
At 20~40 DEG C, colloidal sol lateral pressure is controlled in 0.04MPa~0.1MPa system temperature.
Solvent and solute are separated using ultrafiltration membrane uniform subtle duct when the present invention is concentrated by ultrafiltration, ultrafiltration membrane
When separation, using the pressure difference of film two sides as driving force, using ultrafiltration membrane as filter medium, under pressure, when stoste flows through
When film surface, the densely covered many tiny micropores of ultrafiltration membrane surface only allow water and small-molecule substance by becoming permeate,
And the substance that volume is greater than film surface micropore diameter in stoste is then trapped within the liquid feeding side of film, becomes concentrate, thus realization pair
The purpose of purification, separation and the concentration of stoste.The membrane material of ultrafiltration membrane mainly has cellulose and its derivates, polycarbonate, gathers
Vinyl chloride, Kynoar, polysulfones, polyacrylonitrile, polyamide, polysulfonamides, sulfonated polysulfone, the polyvinyl alcohol of interlinkage, modification
Acrylate copolymer etc..When being used for colloidal dispersion, pvf film may be selected as ultrafiltration membrane, film both ends pressure differential range
For 0.05~0.15MPa, collosol temperature range is 20~40 DEG C.
Pervaporation is also known as seepage slope, is the film process of osmosis along with phase transformation, and film upstream is continuously inputted by heating
Liquid, and the downstream of film with vacuum pump suction cause negative pressure, so that becoming specific liquid component constantly does steam transmission
Seperation film.In colloidal dispersion, Na-A type molecular screen membrane may be selected and carry out pervaporation, film upstream liquid temperature model when concentration
Enclosing is 20~40 DEG C, and 30~40 DEG C of preferred scope, steam end pressure range is 0~30kPa (absolute pressure), preferred scope is 0~
20kPa (absolute pressure)；
It is evaporated under reduced pressure and is also known as evaporated in vacuo, be the evaporation process method for being evaporated operation at sub-atmospheric pressure.It is right
When system according to the present invention, reduction vaporization, liquid temperature range be 20~40 DEG C, 30~40 DEG C of preferred scope, environment
Pressure limit is 0~30kPa (absolute pressure), and preferred scope is 0~20kPa (absolute pressure)；
Concentration preferentially is evaporated to starting sol using reduction vaporization in the present invention.
The synthetic method of above-mentioned nano-sized ZSM-5 zeolite, wherein silicon source described in step S2, source of aluminium, the mould
Plate agent is with Al2O3、SiO2、Na2O、H2The molar ratio computing of O and template, wherein n (Al2 O3):n(SiO2):n(Na2O):n
(H2O): n (template)=0.0001~0.01:1:0.0001~0.25:20~50:0.1~0. 3.
Above-mentioned Na2Sodium atom in O derives from silicon source, the summation of silicon source and template, above-mentioned H2O derives from silicon source, aluminium
The summation of water in source and template.
The synthetic method of above-mentioned nano-sized ZSM-5 zeolite, wherein silicon source described in step S2, source of aluminium, the mould
Plate agent is with Al2O3、SiO2、Na2O、H2The molar ratio computing of O and template, specifically, SiO2/Al2O3=25~∞, Na2O/Al2O3
=0~1, template/SiO2=0.1~0.3, H2O/SiO2=20~50.
The synthetic method of above-mentioned nano-sized ZSM-5 zeolite, wherein mixed sols described in step S3 is with Al2O3、SiO2、
Na2O、H2The molar ratio computing of O and template, wherein n (Al2O3):n(SiO2):n(Na2O): n(H2O): n (template)=
0.0001-0.01:1:0.0001-0.25:6-16:0~1.0.
The synthetic method of above-mentioned nano-sized ZSM-5 zeolite, wherein mixed sols described in step S3 is with A l2O3、SiO2、
Na2O、H2The molar ratio computing of O and template, specifically, SiO2/Al2O3=25~∞, N a2O/Al2O3=0~1, template/
SiO2=0.1~0.3, H2O/SiO2=6~16.
The synthetic method of above-mentioned nano-sized ZSM-5 zeolite, wherein the silicon source is selected from organic silicon source or inorganic silicon source, institute
Organic silicon source is stated in ethyl orthosilicate, methyltriethoxysilane, dimethyl diethoxysilane or ammonia type silica solution
It is one or more；It is water-soluble that source of aluminium is selected from aluminum sulfate saturated aqueous solution, aluminium isopropoxide saturated aqueous solution, sodium metaaluminate saturation
One of liquid, aluminum nitrate saturated aqueous solution, aluminium chloride saturated aqueous solution or aluminium hydroxide aqueous solution are a variety of；The template
Agent can be selected from one of n-butylamine, ethylenediamine, tetraethyl ammonium hydroxide, tetrapropylammonium hydroxide or poly-methyl pyrrole or more
Kind.
The synthetic method of above-mentioned nano-sized ZSM-5 zeolite, wherein the crystalline content of the nano-sized ZSM-5 zeolite is greater than
95wt%, or it is greater than 99wt%.
A kind of nano-sized ZSM-5 zeolite prepared according to above-mentioned synthetic method.
The application of above-mentioned nano-sized ZSM-5 zeolite in the catalyst.
In the prior art, synthesized nano zeolite still needs the process of washing, and is a necessary process, washing
Purpose there are two: 1, remove and be attached to the inorganic base of zeolite surface, prevent alkali from destroying the knot of zeolite in High temperature release
Structure；2, it is removed without the unformed SiO of crystallization2Or Al2O3, the duct of these unformed substance blocking zeolites is prevented, it is influenced
Application performance.And nano zeolite itself is small due to partial size, it is extremely difficult to carry out traditional solid-liquor separation operation, also, due to its granule
The characteristics of diameter, will cause a large amount of loss in washing (zeolite is lost with cleaning solution).From the point of view of the purpose that zeolite washs, such as
Fruit can be avoided the shortcomings that previous system, and zeolite is just not necessarily to washing and convection drying and roasts.
Avoid the destruction of inorganic base: the source of inorganic base is first is that the inorganic base additionally added into system, including hydroxide
Sodium, potassium hydroxide, aluminium hydroxide etc., second is that the metal ion in organic base and system is exchanged with each other and natural production, such as to body
Sodium chloride, sodium fluoride, sodium bromide etc. are added in system, for zeolite structured, metal ion with often with the aluminium of zeolite skeleton
Pairing charge is formed, therefore, if the amount of metal ion is less than or equal to the amount of zeolite skeleton aluminium, metal ion and organic base shape
It can be neglected at the problem of inorganic base, but after metal ion excess significantly, being formed by inorganic base must be washed
Fall, in order to avoid the crystal structure of zeolite, Na of the invention are destroyed in dry and roasting process2O/Al2O3Range between 0~1,
It can avoid the phenomenon that inorganic base destroys.
Avoid unformed SiO2Or Al2O3Blocking zeolite cavity: solve the problems, such as that having its source in for this improves zeolite compound body
It is the utilization rate to raw material, a series of survey is carried out to the product synthesized for this purpose, needing to sample before being dried or roasting
Examination and calibration, these tests include crystal phase test, framework aluminum content test, framework si-al ratio test, crystalline content test.
Crystal phase test: the sample after drying and roasting is ground to 5 μm hereinafter, being put into the specimen holder of X-ray diffractometer
Interior, tabletting simultaneously holds up sample, under CuK α radiation, is scanned measurement, obtained spectrogram in the range of 2 θ=5-35 °
ZSM-5 chromatogram accordance disclosed in association is sieved with International Molecular, without other stray crystal phases.
Framework aluminum content test: the sample that drying was calcined is being filled into saturation NH4Water in the closing vessel of Cl solution
It in unification week, is collected in Nuclear Magnetic Resonance later27Al signal simultaneously draws spectrogram, and in spectrogram, the signals assignment near δ 55 is in boiling
Framework aluminum (the Al of stoneF), the signals assignment near δ 0 is in the non-framework aluminum (Al of zeoliteNF), the content of non-framework aluminum then passes through meter
The resonance peak intensity for calculating the two obtains.
Framework si-al ratio test: the sample that drying was calcined is placed in solid-state nuclear magnetic resonance instrument, is collected29Si signal is simultaneously
Spectrogram is drawn, in spectrogram, nearby signal is respectively belonging to Si (0Al), Si (1Al), Si by δ -106, δ -101, δ -95, δ -90
(2Al) and Si (3Al), Si (4Al) signal is due to very weak, it is not easy to be observed.Corresponding letter is obtained by being fitted spectrogram
Number integrated intensity, is calculated as follows skeleton Si/Al molar ratio:
Crystalline content: due to nano zeolite with XRD test when have extinction, XRD diffracted intensity obtained
The natural zeolite for being less than (Asia) micro-meter scale, therefore, it is impossible to illustrate or demarcate nano zeolite using common relative crystallinity
Crystallization degree, here, present invention introduces this index of crystalline content, to demarcate the crystallization degree of nano zeolite.
The crystalline content of zeolite is measured using ammonia process is inhaled, i.e., sample boils modification with ammonium chloride, after water washing,
Add Klorvess Liquid to act on, the ammonium ion of exchange is cemented out, formaldehyde is then added, the ammonium ion and formaldehyde being displaced
Effect forms hydrochloric acid, is titrated with standard caustic soda solution, calculates it and inhales ammonia amount, concrete operation method is shown in GB/T 21695-
2008 " feed grade zeolite powders ".
The crystalline content of zeolite is determined by comparing the ratio between suction ammonia amount of sample and standard sample, it may be assumed that
Zeolite standard sample is that high-purity, granularity is greater than 25 μm of ZSM-5 zeolite single crystals, the standard sample will as XRD,27Al
NMR、29Benchmark when Si NMR and crystalline content are tested, specific synthetic method are shown in comparative example 1.
The present invention need to sample synthesized product and carry out the above test, be fully achieved following before implementation steps S5
Product directly can be dried and be roasted after standard, specific test index are as follows:
X-ray diffraction method: sample exists without obvious stray crystal or unformed substance；
27Al nuclear magnetic resonance method: total al proportion < 0.3% of non-framework aluminum Zhan, preferably < 0.1%；
29Si nuclear magnetic resonance method: framework si-al ratio differs < 5% with the silica alumina ratio that feeds intake, preferably < 3%；
Crystalline content test: crystalline content > 95%, preferably greater than > 99%；
Compared with prior art, the synthetic method and its application of a kind of nano-sized ZSM-5 zeolite provided by the invention, reaches
Have the technical effect that 1, the present invention provides one kind in three-dimensional, partial size is respectively less than 100nm, and narrow particle size distribution is received
The synthetic method of rice ZSM-5 zeolite, this method avoid nano zeolite separation from without washing to product from source
Difficult awkward situation, cost is controllable, it is horizontal to meet existing industrial equipment at present, has the technical foundation of large-scale production, has very
Strong practicability；2, the present invention adjusts the tune of oligomeric silicic acid root nucleation and autohemagglutination by changing the temperature of adjustment synthetic system
Whole competitive relation to achieve the purpose that inhibit oligomeric silicic acid root autohemagglutination, and then obtains the nano-ZSM-5 of narrow particle size distribution
Zeolite；3, what nano-sized ZSM-5 zeolite of the invention observed under electronic scanner microscope, which determine direction maximum diameter, is less than
100nm can be used as active component or carrier, the active component of adsorption separating agent or carrier, detection of gas of solid acid catalyst
The gas-sensing probe of device special uses coating material.
Below just in conjunction with the embodiments, the embodiment of the present invention is described in further detail, so that technical solution is more
It should be readily appreciated that, grasp.
Detailed description of the invention
Fig. 1 is the polymeric XRD spectra of nano-sized ZSM-5 zeolite prepared by comparative example 2；
Fig. 2 is the polymeric stereoscan photograph of nano-sized ZSM-5 zeolite prepared by comparative example 2；
Fig. 3 is the XRD spectra of nano-sized ZSM-5 zeolite prepared by embodiment 1；
Fig. 4 is the stereoscan photograph of nano-sized ZSM-5 zeolite prepared by embodiment 1；
Fig. 5 is the XRD spectra of nano-sized ZSM-5 zeolite prepared by embodiment 2；
Fig. 6 is the stereoscan photograph of nano-sized ZSM-5 zeolite prepared by embodiment 2；
Fig. 7 is the XRD spectra of nano-sized ZSM-5 zeolite prepared by embodiment 3；
Fig. 8 is the stereoscan photograph of nano-sized ZSM-5 zeolite prepared by embodiment 3；
Fig. 9 is the XRD spectra of nano-sized ZSM-5 zeolite prepared by embodiment 4
Figure 10 is the stereoscan photograph of nano-sized ZSM-5 zeolite prepared by embodiment 4；
Figure 11 is the XRD spectra of nano-sized ZSM-5 zeolite prepared by embodiment 5；
The stereoscan photograph of nano-sized ZSM-5 zeolite prepared by Figure 12 embodiment 5；
Figure 13 is the XRD spectra of nano-sized ZSM-5 zeolite prepared by embodiment 6；
The stereoscan photograph of nano-sized ZSM-5 zeolite prepared by Figure 14 embodiment 6；
Figure 15 is ZSM-5 zeolite crystallization process schematic diagram.
Specific embodiment
The present invention will be described below by way of specific embodiments, but the present invention is not limited thereto.In following embodiments
The experimental method is unless otherwise specified conventional method；The reagent and material unless otherwise specified can be from quotient
Industry approach obtains, the scope of the patents that following example is not intended to limit the invention, all equivalent realities without departing from carried out by the present invention
It applies or changes, be intended to be limited solely by the scope of this patent.
The synthesis of the high-purity ZSM-5 zeolite of 1 big crystal grain of comparative example
By 17.9gNH4F, 2.1g sodium metaaluminate, 1500g water, 220g tetrapropylammonium hydroxide (25wt% aqueous solution) exist
It mixes at room temperature, after forming uniform solution, 220g ethyl orthosilicate is added, stirs 4 hours under the conditions of 80 DEG C later, obtains
To uniform gel, this gel is transferred in stainless steel autoclave, 160 DEG C crystallization 48 hours, obtained product passes through
It is filtered, washed, dries, roasting (550 DEG C, 5 hours) and being exchanged for Hydrogen, XRD diffraction shows that the sample is MFI structure, SEM
Observation shows that the sample is the monocrystalline of 25 μ or more, and crystal form is complete.Using the sample as standard sample, for demarcating nano zeolite
Relative crystallinity, crystalline content.
The nanocrystalline polymeric synthesis of comparative example 2
By method disclosed in Chinese patent CN 102826568A: by 0.149g aluminium isopropoxide and 15.624g silicic acid second
Ester is mixed and added into 26g water and 1h is stirred at room temperature, and 10.98g tetrapropylammonium hydroxide (25wt%) then is added dropwise, after 2 hours
The mixed solution of 0.72gNaOH and 30g water is added dropwise, stirs 3~6 hours under conditions of 40 DEG C as clear solution, is transferred to
Continue stirring 2 days in 100 DEG C of oil bath, above-mentioned reaction carries out in the 250ml conical flask of favorable sealing property, will be above-mentioned molten
90ml water and 24g ethyl alcohol is added after being cooled to room temperature in liquid, and it is small that mixed system is packed into continuation crystallization 24 in 150 DEG C of water heating kettle
When, gained mixed liquor obtains the nanocrystalline polymerization of ZSM-5 of Si/Al=100 after suction filtration, washing, drying, roasting after crystallization
Body.Attached drawing 1 is the nanocrystalline XRD spectra and scanning electron microscope image.Scanning electron microscope image shows that this is nanocrystalline polymeric
Partial size is between 200~600nm.
For Examples 1 to 6 with n-butylamine, aluminum sulfate and ethyl orthosilicate synthesize the nano-sized ZSM-5 zeolite of different silica alumina ratios
By synthesis condition listed by table 4, by 24g n-butylamine, aluminum sulfate aqueous solution and 714g ethyl orthosilicate at -4-4 DEG C
At a temperature of be pre-chilled for 24 hours, the silicon source after pre-cooling, silicon source, organic formwork agent are directly mixed under the conditions of -4-15 DEG C, stirring is equal
It is even, obtain starting sol；Starting sol is placed in water-bath, thickening temperature is 30-35 DEG C, starts to depressurize in gentle agitation
It is concentrated by evaporation, after two hours, the entire quiet weight loss of starting sol system is 844g, obtains mixed sols；Mixed sols is transferred to 1L
In stainless steel crystallizing kettle, and at a temperature of 180 DEG C, static crystallization 48h obtains product suspension；By product suspension directly 60
Dry at DEG C roasting 12h is demoulded at 400 DEG C later for 24 hours, obtains nano-sized ZSM-5 zeolite.
4 embodiment 1-6 nano zeolite synthesis condition of table
| Embodiment | 1 | 2 | 3 | 4 | 5 | 6 |
| N-butylamine/g | 24 | 24 | 24 | 24 | 24 | 24 |
| Water/g | 1100 | 1100 | 1100 | 1100 | 1100 | 1100 |
| Ethyl orthosilicate/g | 714 | 714 | 714 | 714 | 714 | 714 |
| Aluminum sulfate/g | 12.3 | 6.2 | 3.1 | 1.5 | 0.8 | 0 |
| Precooling temperature/DEG C | 4 | 0 | -4 | -2 | 2 | -4 |
| Mixing temperature/DEG C | -4 | 5 | 10 | 10 | 0 | 15 |
| Thickening temperature/DEG C | 35 | 32 | 30 | 30 | 32 | 35 |
Table 5 is some physical and chemical indexes of the obtained nano-sized ZSM-5 zeolite of Examples 1 to 6.Scanning electron microscope knot in attached drawing
Fruit illustrates that synthesized zeolite particle size is in 100nm hereinafter, particle size distribution narrow scope.
Nano zeolite performance synthesized by 5 Examples 1 to 6 of table
For embodiment 7~10 with tetrapropylammonium hydroxide, sodium metaaluminate and ammonia type silica solution synthesize the nanometer of different silica alumina ratios
ZSM-5 zeolite
220 tetrapropylammonium hydroxide, Xg sodium metaaluminate are added in 1100g water, form solution, X is according to required for
Silica alumina ratio is respectively 4.14,2.07,1.04 and 0g) and 500g ammonia type silica solution be pre-chilled at a temperature of -4 DEG C for 24 hours, will be pre-chilled
Raw material afterwards directly mixes.
Colloidal sol is placed in water-bath, is warming up to 30 DEG C, and gentle agitation starts to subtract until forming uniform colloidal sol
Pressure evaporation, after two hours, the entire quiet weight loss of sol system is 951g, is transferred in 1L stainless steel crystallizing kettle, and in 180 DEG C of temperature
Under degree, static crystallization 48h.
After crystallization, product suspension is dry directly at 60 DEG C, and roasting 12h is demoulded at 400 DEG C later for 24 hours, is obtained
To nano-sized ZSM-5 zeolite.Scanning electron microscope shows that the particle diameter distribution of embodiment 7~10 is distributed between 100 ± 20nm 100.
Table 6 is 7~12 some physical and chemical indexes of obtained nano-sized ZSM-5 zeolite of embodiment.
Nano-sized ZSM-5 zeolite performance synthesized by 6 embodiment 7~10 of table
Embodiment 11
Comparative example 2 and embodiment 3 are made respectively, catalyst is made according to preceding method, and evaluated it and split in normal octane
Catalytic performance in solution reaction, product component is as listed by table 7.
The catalytic performance of 7 comparative example 2 of table and embodiment 3 in normal octane cracking
Embodiment 12
Comparative example 2 and embodiment 3 are made respectively, catalyst is made according to preceding method, and evaluated it and converted in methanol
Catalytic performance in reaction, product component is as listed by table 8.The regeneration period is that methanol conversion dropped to before 90% in table 8
Accumulative operation duration, product is distributed as accumulative average value.
The catalytic performance of 8 comparative example 2 of table and embodiment 3 in methanol conversion
Catalysis reaction and evaluation method
The Catalytic data of normal octane cracking and methanol conversion is disclosed in the present embodiment to prove the nanometer of the invention synthesized
ZSM-5 zeolite has efficient catalytic performance.
Normal octane can be used as fcc product, raw gasoline, raffinate oil, the representative species of biomass components, and methanol then can be used as
The representative substances of the oxygenatedchemicals of C1~4.
The preparation method of catalyst: by 40~80 DEG C of dried nano-sized ZSM-5 zeolites (absolute contents on dry basis >
80%) 200 mesh or more are crushed to, and with boehmite (SB powder, German SASOL are produced), sesbania powder according to mass ratio 8:2:
0.05 ratio mixing, on the basis of the mixture, is added the nitric acid solution (nitric acid content 5wt%) of 50wt%, is mixed into
Uniform colloid, extruded moulding, dries at a temperature of 110 DEG C and roasts 5~10h at 550 DEG C, obtain white strip later
Object, the white bar crushing and screening to 20~40 mesh, uses the NH of 1mol/L4NO3Solution carries out ammonium exchange, give-and-take conditions
Are as follows: solid masses/NH4NO3Solution quality=1:10,85 DEG C of exchange temperature, swap time 2 hours, the particle after exchange passed through
After filter, washing, in 110 DEG C of dryings and in 550 DEG C of roasting 5h, is sieved later to 20~40 mesh to get catalyst, be used as catalysis
Evaluation.
Catalytic evaluation device selects stainless steel tube reactor, and loaded catalyst is 0.1~5g.Select 20~40 purposes
Acid-washed quartz sand is dilution.When evaluation, catalyst total filling amount is 1mg, packing method are as follows: by the catalyst of 1g and 3g
60 milliliters or so of ethyl alcohol is added later and stirs to form slurry, ultrasonic activation 10 minutes or so, then exists for diluent mixing
Dry 2 hours removing ethyl alcohol is packed into reaction tube after the substance after drying takes out in 100 DEG C of baking oven.
It is catalyzed the condition of reaction are as follows:
1, normal octane cracks
450 DEG C of reaction temperature, reaction pressure is normal pressure, specific method: the catalyst that 1g is mixed/quartz sand mixing
Object is packed into the constant temperature fragment position of reaction tube, is then passed through nitrogen according to the flow of 170ml/min, tube temperature will be reacted after half an hour
Degree is increased to 450 DEG C, and keeps N2Flow is passed through normal octane into reaction tube using syringe pump after temperature is constant, just pungent
The flow of alkane is 0.33g/h, takes reaction tube exit gas at interval of 1h, analyzes component using gas-chromatography (GC).
2, methanol converts
470 DEG C of reaction temperature, reaction pressure is normal pressure, and specific method is that the catalyst/quartz sand for mixing 1g mixes
The constant temperature fragment position that object is packed into reaction tube is closed, then nitrogen is passed through according to the flow of 170ml/min, by reaction tube after half an hour
Temperature is increased to 450 DEG C, and after temperature is constant, nitrogen is closed.Then methanol and water are passed through into reaction tube using syringe pump
Mixture (mass ratio of methanol and water be 1/0.65), the flow of mixture is 0.55g/h, takes reaction tube to go out at interval of 1h
Gas analyzes component using gas-chromatography (GC).
Fid detector is selected in GC analysis, and PLOT-Q capillary column is selected in separation, analyzes duration 45min.Sample is may be used at
Line automatic sampling can also be taken and manually sample.Heretofore described sampling method is manually to sample.Data point
Internal standard method normalizing is taken in analysis.
Several preferred embodiments of the invention have shown and described in above description, but as previously described, it should be understood that the present invention
It is not limited to forms disclosed herein, should not be regarded as an exclusion of other examples, and can be used for various other groups
Close, modification and environment, and can within that scope of the inventive concept describe herein, by the technology of above-mentioned introduction or related fields or
Knowledge is modified.And changes and modifications made by those skilled in the art do not depart from the spirit and scope of the present invention, then it all should be
In the protection scope of appended claims of the present invention.
Claims (10)
1. a kind of synthetic method of nano-sized ZSM-5 zeolite, which comprises the steps of:
S1. it pre-processes: 4~48h is pre-chilled in silicon source, silicon source, template respectively, precooling temperature is -10~10 DEG C；
S2. it prepares: the silicon source after pre-cooling, silicon source, template being mixed evenly respectively, mixing temperature is -10~30 DEG C, is obtained
Starting sol；
S3. it is concentrated: the colloidal sol being concentrated to give mixed sols while stirring, thickening temperature is 20~40 DEG C；
S4. by mixed sols, 12~72h of crystallization, crystallization temperature are 140~200 DEG C in high pressure crystallizing kettle, obtain product suspension；
S5. by 40~80 DEG C of dryings of product suspension, 350~600 DEG C of roasting Template removals obtain nano-sized ZSM-5 zeolite.
2. the synthetic method of nano-sized ZSM-5 zeolite according to claim 1, which is characterized in that be pre-chilled described in step S1
Temperature is -4~4 DEG C, and mixing temperature described in step S2 is -4~15 DEG C, and thickening temperature described in step S3 is 30~35 DEG C,
Drying temperature described in step S5 is 40~60 DEG C, and the roasting calcining temperature is 300~400 DEG C.
3. the synthetic method of nano-sized ZSM-5 zeolite according to claim 1, which is characterized in that silicon source described in step S2,
Source of aluminium, the template are with Al2O3、SiO2、Na2O、H2The molar ratio computing of O and template, wherein n (Al2O3):n(SiO2):
n(Na2O):n(H2O): n (template)=0.0001~0.01:1:0.0001~0.25:20~50:0.1~0.3.
4. the synthetic method of nano-sized ZSM-5 zeolite according to claim 3, which is characterized in that silicon source described in step S2, institute
Silicon source, the template are stated with Al2O3、SiO2、Na2O、H2The molar ratio computing of O and template, specifically, SiO2/Al2O3=25~
∞, Na2O/Al2O3=0~1, template/SiO2=0.1~0.3, H2O/SiO2=20~50.
5. the synthetic method of nano-sized ZSM-5 zeolite according to claim 1, which is characterized in that mixed described in step S3
Colloidal sol is with Al2O3、SiO2、Na2O、H2The molar ratio computing of O and template, wherein n (Al2O3):n(SiO2):n(Na2O):n
(H2O): n (template)=0.0001-0.01:1:0.0001-0.25:6-16:0~1.0.
6. the synthetic method of nano-sized ZSM-5 zeolite according to claim 5, which is characterized in that mixed described in step S3
Colloidal sol is with Al2O3、SiO2、Na2O、H2The molar ratio computing of O and template, specifically, SiO2/Al2O3=25~∞, Na2O/Al2O3
=0~1, template/SiO2=0.1~0.3, H2O/SiO2=6~16.
7. the synthetic method of nano-sized ZSM-5 zeolite according to claim 1, which is characterized in that the silicon source is selected from organic
Silicon source or inorganic silicon source, the organic silicon source are selected from ethyl orthosilicate, methyltriethoxysilane, dimethyl diethoxysilane
Or one of ammonia type silica solution or a variety of；Source of aluminium be selected from aluminum sulfate saturated aqueous solution, aluminium isopropoxide saturated aqueous solution, partially
One of aluminic acid saturated aqueous solution of sodium, aluminum nitrate saturated aqueous solution, aluminium chloride saturated aqueous solution or aluminium hydroxide aqueous solution or
It is a variety of；The template can be selected from n-butylamine, ethylenediamine, tetraethyl ammonium hydroxide, tetrapropylammonium hydroxide or poly-methyl pyrrole
One of or it is a variety of.
8. the synthetic method of nano-sized ZSM-5 zeolite according to claim 1, which is characterized in that the nano-sized ZSM-5 zeolite
Crystalline content be greater than 95wt%, or be greater than 99wt%.
9. a kind of nano-sized ZSM-5 zeolite of synthetic method preparation according to claim 1-8.
10. the application of nano-sized ZSM-5 zeolite according to claim 9 in the catalyst.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910395327.6A CN110282635A (en) | 2019-05-13 | 2019-05-13 | A kind of synthetic method and its application of nano-sized ZSM-5 zeolite |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910395327.6A CN110282635A (en) | 2019-05-13 | 2019-05-13 | A kind of synthetic method and its application of nano-sized ZSM-5 zeolite |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110282635A true CN110282635A (en) | 2019-09-27 |
Family
ID=68001938
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910395327.6A Pending CN110282635A (en) | 2019-05-13 | 2019-05-13 | A kind of synthetic method and its application of nano-sized ZSM-5 zeolite |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110282635A (en) |
-
2019
- 2019-05-13 CN CN201910395327.6A patent/CN110282635A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105431380B (en) | Zeolite with classification porosity | |
| RU2540550C2 (en) | Method of obtaining zeolite zsm-5 with application of nanocrystal seeds zsm-5 | |
| CN105032478B (en) | A kind of catalyst and its dedicated core-shell structure compound molecular sieve for the oily isomerization-visbreaking of F-T synthetic middle distillates point | |
| CN108793185A (en) | A kind of preparation method of nano-ZSM-5 molecular sieve | |
| CN104229826A (en) | ZSM-5 molecular sieve and preparation method thereof | |
| CN101983921A (en) | Method for synthesizing ZSM-5 zeolite orderly accumulated by nanometer crystallite | |
| CN106219569B (en) | A method of no one step of secondary template prepares porous zeotile | |
| CN110002461A (en) | A kind of rose-shaped SAPO-5 molecular sieve of stamen and its preparation and application again | |
| CN112794338A (en) | ZSM-5 molecular sieve and preparation method and application thereof | |
| CN106276964B (en) | A kind of transgranular phosphorous ZSM-5 molecular sieve and preparation method thereof | |
| CN105523568B (en) | The molecular sieves of one-dimensional rod-like pattern ZSM 5 and synthetic method | |
| CN107840349B (en) | Preparation method of nano ZSM-5 hierarchical pore aggregate | |
| CN106276967B (en) | A kind of synthetic method of mesoporous zeolite | |
| CN110282635A (en) | A kind of synthetic method and its application of nano-sized ZSM-5 zeolite | |
| Yin et al. | Studies on the formation of hierarchical zeolite T aggregates with well-defined morphology in different template systems | |
| Zhang et al. | Synthesis of hierarchical MFI zeolites with a micro–macroporous core@ mesoporous shell structure | |
| US11124421B2 (en) | Process for the synthesis, with multiple seeding, of zeolite crystals having a controlled particle size | |
| CN106423262A (en) | SAPO-34 molecular sieve based catalyst with ordered middle holes and preparation method thereof | |
| CN109678176A (en) | The synthetic method of the needle-shaped ZSM-5 molecular sieve of size tunable | |
| CN101417810A (en) | Mesoporous material and preparation method thereof | |
| CN112456511B (en) | SAPO-34 molecular sieve, and preparation method and application thereof | |
| CN114560474A (en) | Synthesis method of metal modified M-MFI molecular sieve membrane | |
| Ren et al. | Controllable synthesis of obvious core–shell structured Y/Beta composite zeolite by a stepwise-induced method | |
| CN111186846B (en) | ITH structure silicon-aluminum molecular sieve and preparation method thereof | |
| CN106629768A (en) | Synthetic method for uniform nanosized ZSM-5 molecular sieve |
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 |