CN111825103B

CN111825103B - Fluorine-containing high-silicon Y molecular sieve and preparation method thereof

Info

Publication number: CN111825103B
Application number: CN201910312332.6A
Authority: CN
Inventors: 王林英; 田鹏; 朱大丽; 刘中民; 李冰; 张建明
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2019-04-18
Filing date: 2019-04-18
Publication date: 2022-04-12
Anticipated expiration: 2039-04-18
Also published as: CN111825103A

Abstract

The application discloses a fluorine-containing high-silicon Y molecular sieve and a preparation method thereof, belonging to the field of molecular sieve synthesis. The anhydrous chemical composition of the fluorine-containing high-silicon Y molecular sieve is hF. kM. mR 1. nR2 (Si)_xAl_y)O₂The Si/Al ratio is 25-100. The method comprises the following steps: a) mixing raw materials containing an aluminum source, a silicon source, an alkali metal source, a fluorine source, an organic template agent R2 and water to obtain initial gel, then adding a guiding agent or a silicon-aluminum molecular sieve seed crystal, and stirring to obtain synthetic gel; b) removing water from the synthetic gel to obtain a dry powder mixture; c) crystallizing the dry powder mixture. The fluorine-containing high-silicon Y molecular sieve has high silicon-aluminum ratio and low alkali metal content, and is easy to carry out ion exchange; the preparation method has the advantages of high crystallization rate and simple process, and is beneficial to large-scale industrial production.

Description

Fluorine-containing high-silicon Y molecular sieve and preparation method thereof

Technical Field

The application relates to a fluorine-containing high-silicon Y molecular sieve and a preparation method thereof, in particular to a method for synthesizing the fluorine-containing high-silicon Y molecular sieve under ultralow water content by introducing an organic template agent into a synthetic gel system and adding a guiding agent or a seed crystal, belonging to the field of molecular sieve synthesis.

Background

The Y molecular sieve is a silico-aluminum molecular sieve with FAU topology, mainly applied to Fluid Catalytic Cracking (FCC), and is the most used molecular sieve material at present. The framework silica-alumina ratio of the Y molecular sieve plays a decisive role in the catalytic performance, wherein the higher the silica-alumina ratio is, the better the catalytic activity and the stability are. At present, the high-silicon Y molecular sieve used in industry is mainly obtained by chemical/physical dealumination and the like, the post-treatment method has the defects of complicated process, high energy consumption and heavy pollution, and the direct hydrothermal synthesis can effectively avoid the defects and simultaneously maintain the integrity of a crystal structure and the uniformity of aluminum distribution. Therefore, the exploration of direct method for synthesizing the Y molecular sieve with high silica-alumina ratio has very important significance for the catalytic cracking process.

For synthesizing the high-silicon Y molecular sieve by the direct method, people firstly synthesize the high-silicon Y molecular sieve in a non-template system, namely, no organic template is added into reaction gel, and the aim of improving the silicon-aluminum ratio of the Y molecular sieve is achieved only by adjusting the gel proportion, the crystallization time, the preparation method of seed crystals or inorganic directing agents and the like, but the yield is very low, and the silicon-aluminum ratio is difficult to reach 6.

The use of the organic structure directing agent brings the synthesis of the Y molecular sieve into the brand-new field, and in 1987, the U.S. Pat. No. 4, 4,714,601 discloses an ECR-4 FAU polymorph with a silicon-aluminum ratio of more than 6, which is obtained by taking alkyl or hydroxyalkyl quaternary ammonium salt as a template agent and carrying out hydrothermal crystallization at 70-120 ℃ in the presence of seed crystals.

In 1990, US 4,931,267 discloses a FAU polymorph named ECR-32 with a Si/Al ratio greater than 6, which is obtained by hydrothermal crystallization at 90-120 ℃ using tetrapropyl and/or tetrabutyl ammonium hydroxide as a structure directing agent and has high thermal stability.

In 1990, French Delprato et al (Zeolite, 1990,10(6):546-552) synthesized FAU molecular sieve with cubic structure for the first time by using crown ether as a template, the framework silica-alumina ratio is close to 9.0, which is the highest value that can be realized by the one-step method reported in the literature at present, but the expensive and extremely toxic properties of the crown ether limit the industrial application.

Disclosure of Invention

According to one aspect of the application, the fluorine-containing high-silicon Y molecular sieve is provided, the silicon-aluminum ratio of the molecular sieve is up to 25-100, the content of alkali metal is low, and ion exchange is easy to perform.

The fluorine-containing high-silicon Y molecular sieve is characterized in that the anhydrous chemical composition of the fluorine-containing high-silicon Y molecular sieve is shown as a formula I:

hF·kM·mR1·nR2·(Si_xAl_y)O₂formula I

Wherein F represents fluoride ion;

m is at least one selected from alkali metal elements;

r1 and R2 respectively represent organic templates;

h represents per mole (Si)_xAl_y)O₂H is 0.01 to 0.2;

k represents (Si) per mole_xAl_y)O₂K is 0 to 0.1 in terms of the number of moles of the corresponding alkali metal element;

m and n represent each mole of (Si)_xAl_y)O₂The mole number of the corresponding organic template R1 and organic template R2 is 0-0.2; n is 0.01 to 0.2;

x and y represent mole fractions of Si and Al, 2x/y is 25-100, and x + y is 1.

Optionally, M is selected from at least one of sodium, potassium, and cesium; sodium is preferred.

Optionally, h is 0.01-0.15; k is 0-0.08; m is 0 or 0.01 to 0.1; n is 0.03 to 0.16.

Optionally, h is 0.02-0.1; k is 0.01 to 0.05; m is 0 or 0.02-0.05; n is 0.06 to 0.16.

Optionally, under the condition that x + y is 1, the upper limit of 2x/y is selected from 100, 98, 95, 92, 89, 88, 85, 83, 80, 76, 75, 73, 70, 68, 66, 65, 64, 63, 60, 59, 56, 54, 53, 51, 48, 46, 45, 42, 40, 38, 37, 36, 35, 34, 31, 29, 28, 26, and the lower limit is selected from 25, 26, 38, 29, 31, 34, 35, 36, 37, 38, 40, 42, 45, 46, 48, 51, 53, 54, 56, 59, 60, 63, 64, 65, 66, 68, 70, 73, 75, 76, 80, 83, 85, 88, 89, 92, 95, 98.

Optionally, the organic templating agent R1 is selected from at least one of the quaternary ammonium compounds having the formula shown in formula II:

wherein R is₁、R₂、R₃And R₄Independently selected from C₁～C₁₂Alkyl of (C)₁～C₁₂Alkoxy group of (C)₁～C₁₂At least one of hydroxyalkyl, benzyl and adamantyl; x^n-Selected from OH^-、Cl^-、Br^-、I^-、NO₃ ^-、HSO₄ ^-、H₂PO₃ ^-、SO₄ ^2-、HPO₃ ^2-、PO₃ ^3-。

Preferably, the organic templating agent R1 is selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.

Optionally, the organic template R2 is selected from at least one of quaternary ammonium compound and nitrogen-containing heterocyclic compound with the structural formula shown in formula III:

Preferably, the nitrogen-containing heterocyclic compound is selected from at least one of pyridine, piperidine, imidazole, piperazine and derivatives thereof.

More preferably, the organic templating agent R2 is selected from the group consisting of tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, tetrahexylammonium hydroxide, tetrapropylammonium bromide, tetrabutylammonium chloride, tetrapentylammonium bromide, tripropylisobutylammonium bromide, tributylcyclohexylammonium hydroxide, dibutyldihexylammonium hydroxide, choline, triethylhydroxyethylammonium hydroxide, tripropylhydroxyethylammonium hydroxide, tributylhydroxyethylammonium hydroxide, tributylbenzylammonium hydroxide, triethylbenzylammonium hydroxide, tripropylbenzylammonium hydroxide, triethyladamantylammonium chloride, tripropyladamantylammonium chloride, pyridine, N-methylpyridine, N-ethylpyridine, N-propylpyridine, N-butylpyridine, 1-ethyl-3-butylpyridine hydroxide, 1-ethyl-2-propylpyridine hydroxide, tetrabutyl adamantylammonium chloride, and mixtures thereof, Piperidine, N-dimethylpiperidine, N-dimethyl-3, 5-diethylpiperidine hydroxide, N-dimethyl-3, 5-dipropylpiperidine hydroxide, N-diethyl-3, 5-dipropylpiperidine hydroxide, N-dimethyl-2, 6-dimethylpiperidine hydroxide, N-hydroxide, at least one of N-dimethyl-2, 6-diethylpiperidine, imidazole, 1-ethyl-3-butylimidazole hydroxide, 1-ethyl-3-butyl-4-propylimidazole hydroxide, piperazine, N-methylpiperazine, 1, 4-dipropylpiperazine, 1-methyl-4-ethylpiperazine and 1-ethyl-4-butyl-5-methylpiperazine.

According to another aspect of the application, a preparation method of the fluorine-containing high-silicon Y molecular sieve is provided, wherein the method comprises the steps of introducing an organic template agent into a synthetic gel system, adding a seed crystal or a guiding agent, and substituting at least part of alkali metal ions with a fluorine-containing reagent to synthesize the high-silicon (the silicon-aluminum ratio is 25-100) Y molecular sieve under ultralow water content.

The preparation method of the fluorine-containing high-silicon Y molecular sieve is characterized by comprising the following steps of:

a) mixing raw materials containing an aluminum source, a silicon source, an alkali metal source, a fluorine source, an organic template agent R2 and water to obtain initial gel, then adding a guiding agent or a silicon-aluminum molecular sieve seed crystal, and stirring to obtain synthetic gel;

b) removing water from the synthetic gel to obtain a dry powder mixture;

c) and crystallizing the dry powder mixture to obtain the fluorine-containing high-silicon Y molecular sieve.

Optionally, the preparation of the directing agent comprises the steps of:

a0) the directing agent is obtained by mixing raw materials containing an aluminum source, a silicon source, an alkali metal source, an organic template agent R1 and water, and then aging.

Optionally, the fluorine source is selected from at least one of hydrofluoric acid and ammonium fluoride.

Optionally, the silicon source in step a) and step a0) is independently selected from at least one of methyl orthosilicate, ethyl orthosilicate, silica sol, solid silica gel, silica white and sodium silicate.

Optionally, the aluminum sources in step a) and step a0) are independently selected from at least one of sodium metaaluminate, alumina, aluminum hydroxide, aluminum isopropoxide, aluminum 2-butoxide, aluminum chloride, aluminum sulfate, and aluminum nitrate.

Optionally, the alkali metal source in step a) and step a0) is independently selected from at least one of sodium hydroxide, potassium hydroxide, and cesium hydroxide.

Optionally, the aluminosilicate molecular sieve seeds are zeolitic molecular sieves having FAU or EMT structures.

Optionally, the aluminosilicate molecular sieve seed crystal is selected from Na type and NH₄At least one of type and H zeolite molecular sieves.

In the present application, there is no particular limitation on the range of the silica-alumina ratio of the silica-alumina molecular sieve seed crystal as long as it can be used as a seed crystal for synthesizing a target molecular sieve.

Alternatively, in step a0), the aluminum source, the silicon source, the alkali metal source, the organic template R1 and water are mixed according to the following molar ratios:

1SiO₂:(0.01～0.1)Al₂O₃:(0～0.1)M₂O:(0.1～2)R1:(10～20)H₂O；

wherein the mole number of the silicon source is SiO₂Counting; the mole number of the aluminum source is Al₂O₃Counting; the mole number of the organic template R1 is calculated by the mole number of R1 per se; the molar number of the alkali metal source is equal to the metal oxide M corresponding to the corresponding alkali metal M₂And the mole number of O.

Preferably, in step a0), the aluminum source, the silicon source, the alkali metal source, the organic template R1 and water are mixed according to the following molar ratios:

1SiO₂:(0.017～0.1)Al₂O₃:(0～0.1)M₂O:(0.1～2)R1:(10～20)H₂O；

Optionally, in the step a0), the aging temperature is 25-120 ℃.

Preferably, in step a0), the temperature of the aging is selected from the upper limit of 120 ℃, 110 ℃, 100 ℃, 90 ℃, 80 ℃, 70 ℃,60 ℃, 50 ℃, 40 ℃, 30 ℃ and the lower limit of 25 ℃, 30 ℃, 40 ℃, 50 ℃,60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃.

Optionally, in the step a0), the aging time is 0.5-3 days.

Preferably, in step a0), the aging time is selected from the upper limit of 3 days, 2.5 days, 2 days, 1.5 days, 1 day, and the lower limit is selected from the lower limit of 0.5 days, 1 day, 1.5 days, 2 days, 2.5 days.

Optionally, in step a0), the aging is performed in a dynamic or static manner.

In one embodiment, the aging is performed in a static manner, for example, in a standing manner.

In one embodiment, the aging is carried out in a dynamic manner, for example, in a stirring or rotating manner.

Optionally, in step a0), the aging is performed in a combination of dynamic and static.

Alternatively, in step a), the aluminum source, the silicon source, the alkali metal source, the fluorine source, the organic template R2 and water are mixed according to the following molar ratios:

1SiO₂:(0.005～0.02)Al₂O₃:(0～0.02)M₂O:(0.01～0.5)F:(0.01～0.5)R2:(10～25)H₂O；

wherein the mole number of the silicon source is SiO₂Counting; the mole number of the aluminum source is Al₂O₃Counting; the mole number of the organic template R2 is calculated by the mole number of R2 per se; the molar number of the alkali metal source is equal to the metal oxide M corresponding to the corresponding alkali metal M₂The mole number of O; the moles of fluorine source are based on the moles of fluoride ion.

Preferably, in step a), the aluminum source, the silicon source, the alkali metal source, the fluorine source, the organic template R2 and water are mixed according to the following molar ratio:

1SiO₂:(0.005～0.02)Al₂O₃:(0～0.02)M₂O:(0.01～0.5)F:(0.01～0.5)R2:(12～25)H₂O；

Optionally, in step a), the amount of the guiding agent added is such that SiO in the guiding agent₂In an amount of SiO in the initial gel₂3-20 wt% of the content.

Preferably, in step a), SiO in the directing agent₂The content of SiO in the initial gel₂The upper limit of the mass fraction of the content is selected from 20 wt%, 19 wt%, 18 wt%, 17 wt%, 16 wt%, 15 wt%, 14 wt%, 13 wt%, 12 wt%, 11 wt%, 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, and the lower limit is selected from 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%.

Alternatively, SiO in the directing agent when preparing the synthetic gel₂The content of SiO in the initial gel₂3-20% of the content.

Preferably, the SiO in the directing agent is used in the preparation of the synthesis gel₂The content of SiO in the initial gel₂3-10% of the content.

Optionally, in step a), the directing agent is added to the initial gel in the form of a solution.

Optionally, in step a), the amount of the aluminosilicate molecular sieve seeds added is SiO in the initial gel₂3-20 wt% of the content.

Preferably, in step a), the amount of the aluminosilicate molecular sieve seeds added is relative to the SiO in the initial gel₂The content is selected from the group consisting of 20 wt%, 19 wt%, 18 wt%, 17 wt%, 16 wt%, 15 wt%, 14 wt%, 13 wt%, 12 wt%, 11 wt%, 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt% at the upper limit and 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt% at the lower limit.

Alternatively, in the preparation of the synthetic gel, the addition amount (mass fraction) of the seed crystals accounts for the SiO in the initial gel₂3-20% of the content.

Preferably, in the preparation of the synthetic gel, the addition amount (mass fraction) of the seed crystals is based on the SiO in the initial gel₂3-10% of the content.

Optionally, in the step a), the stirring is performed for 1 to 3 hours.

Preferably, in step a), the stirring is carried out for a time with an upper limit selected from 3 hours, 2.5 hours, 2 hours, 1.5 hours and a lower limit selected from 1 hour, 1.5 hours, 2 hours, 2.5 hours.

Optionally, in step b), removing water from the synthesis gel to H therein₂O and SiO₂The molar ratio of (a) to (b) is 1:1 to 3: 1.

Preferably, in step b), the synthesis gel with water removed has an upper limit of the water to silicon ratio selected from 3.0, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1 and a lower limit selected from 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9.

Optionally, in step b), the water removal is performed by evaporation with heating.

Optionally, in the step b), the temperature of the evaporation is 50-100 ℃.

Preferably, in step b), the temperature of evaporation has an upper limit selected from 100 ℃, 90 ℃, 80 ℃, 70 ℃,60 ℃ and a lower limit selected from 50 ℃,60 ℃, 70 ℃, 80 ℃, 90 ℃.

Preferably, in the step b), the temperature of the evaporation is 50-90 ℃.

Optionally, in step b), the evaporation manner is static evaporation or stirring evaporation.

Optionally, in the step c), the crystallization temperature is 100-180 ℃.

Preferably, in step c), the crystallization temperature has an upper limit selected from 180 ℃, 170 ℃, 160 ℃, 150 ℃, 140 ℃, 130 ℃, 120 ℃ and 110 ℃ and a lower limit selected from 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃ and 170 ℃.

Preferably, in the step c), the crystallization temperature is 120-170 ℃.

Optionally, in the step c), the crystallization time is 0.5 to 10 days.

Preferably, in step c), the upper limit of the crystallization time is selected from 10 days, 9 days, 8 days, 7 days, 6 days, 5 days, 4 days, 3 days, 2 days, 1 day, and the lower limit is selected from 0.5 days, 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days.

Preferably, in the step c), the crystallization time is 1 to 6 days.

Optionally, in step c), the crystallization is performed under closed conditions.

Optionally, in step c), the crystallization is performed under autogenous pressure.

In the method, the crystallization mode in the step c) can be dynamic crystallization or static crystallization,

a combination of the two crystallization modes is also possible.

Optionally, in step c), the crystallization is performed in a dynamic or static manner.

Optionally, in step c), the crystallization is performed in a combination of dynamic and static manner, for example, in a first static and then dynamic manner.

In the present application, dynamic crystallization refers to that the slurry in the crystallization kettle is in a non-standing state, and static crystallization refers to that the slurry in the crystallization kettle is in a standing state. By way of example, the dynamic crystallization may be performed by rotational crystallization.

Optionally, in step c), after said crystallization, the solid product is filtered, washed, dried,

and obtaining the fluorine-containing high-silicon Y molecular sieve.

In the method, the washing, filtering, separating and drying of the obtained Y molecular sieve are all conventional operations. In one embodiment, the separation is selected from centrifugation or suction filtration. In another embodiment, the drying temperature is 100 to 110 ℃ and the time is 12 hours.

In a specific embodiment, the synthesis process of the fluorine-containing high-silicon Y molecular sieve is as follows:

1) preparing a guiding agent: aluminum source, silicon source, organic ammonium (R1) as 1SiO₂:(0.01～0.1)Al₂O₃:(0～0.1)Na₂O:(0.1～2)R1:(10～20)H₂Mixing and stirring the mixture for 2 hours according to the molar ratio of O, and stirring the mixture for 0.5 to 3 days at the temperature of between 25 and 120 ℃ to prepare a guiding agent A;

2) preparing a synthetic gel: aluminum source, silicon source, sodium hydroxide, organic ammonium (R2) as 1SiO₂:(0.005～0.02)Al₂O₃:(0～0.02)Na₂O:(0.01～0.5)F:(0.01～0.5)R2:(10～25)H₂Mixing and stirring the mixture evenly at room temperature according to the molar ratio of O to obtain initial gel B, and then adding a certain amount of seed crystals (the mass fraction of the seed crystals is SiO in the initial gel B)₂3-20% by mass) or a directing agent A (wherein SiO is contained in the directing agent)₂The content of the initial gel SiO₂3-20% of the content) is stirred for 1-3 hours to prepare synthetic gel C;

3) the synthetic gel removed excess water: heating the synthesized gel C at a certain temperature to remove muchResidual water is added into the system H₂O/SiO₂1-3 (molar ratio), and obtaining a dry powder mixture D;

4) synthesis of high-silicon Y zeolite: and crystallizing the dry powder mixture D for 2-10 days at a certain temperature under the autogenous pressure, filtering and separating a solid product after crystallization is finished, washing the solid product to be neutral by using deionized water, and drying to obtain the high-silicon Y zeolite.

According to yet another aspect of the present application, there is provided a catalyst comprising at least one of the fluorine-containing high-silicon Y molecular sieve described above, the fluorine-containing high-silicon Y molecular sieve produced by the above method.

The fluorine-containing high-silicon Y molecular sieve with FAU topological structure prepared by the method can be used for fluidized catalytic cracking catalysts and carriers and catalysts for bifunctional catalysis such as hydrocracking, hydrodesulfurization and the like.

In the context of the present application, the term "silicon to aluminum ratio" means in SiO in a molecular sieve₂And Al₂O₃The molar ratio of silicon to aluminum is calculated and is synonymous with "2 x/y" and "silicon to aluminum oxide ratio" as described herein.

In the context of the present application, the term "water to silicon ratio" means the H content of the resultant gel after removal of water₂O and SiO₂The ratio of the molar ratio of (a) to (b).

In the context of the present application, the term "fluorine source" has the same meaning as "fluorine-containing agent".

The beneficial effects that can be produced by the application include but are not limited to:

1) according to the preparation method of the fluorine-containing high-silicon Y molecular sieve, the organic template agent is introduced into the synthetic gel, the seed crystal or the guiding agent is added, the fluorine-containing agent is adopted to at least partially replace alkali metal ions, and the synthesis of the high-silicon Y molecular sieve with the silicon-aluminum ratio of 25-100 is realized under the condition of ultralow water amount.

2) The preparation method of the fluorine-containing high-silicon Y molecular sieve has the advantages of high crystallization rate and simple process, and is beneficial to large-scale industrial production.

3) The fluorine-containing high-silicon Y molecular sieve provided by the application has low alkali metal content and is easy to carry out ion exchange.

Drawings

Fig. 1 is an X-ray diffraction (XRD) pattern of sample S1.

Fig. 2 is an X-ray diffraction (XRD) spectrum of comparative sample 1.

Fig. 3 is an X-ray diffraction (XRD) spectrum of comparative sample 2.

Fig. 4 is an X-ray diffraction (XRD) pattern of comparative sample 3.

Fig. 5 is an X-ray diffraction (XRD) pattern of sample Y1.

Fig. 6 is an X-ray diffraction (XRD) pattern of comparative sample 4.

Fig. 7 is an X-ray diffraction (XRD) pattern of comparative sample 5.

Detailed Description

As mentioned above, the present application relates to a high silicon Y molecular sieve with FAU topology and its synthesis method, the anhydrous chemical composition of the molecular sieve is hF kNa mR1 nR2 (Si)_xAl_y)O₂Wherein F is a fluoride ion and h represents per mole (Si)_xAl_y)O₂The number of moles of F ion; na is sodium ion and k represents per mole (Si)_xAl_y)O₂The number of moles of Na ion in (A); r1 and R2 represent organic templating agents, present in the microporous structure, and m and n represent each mole (Si)_xAl_y)O₂Moles of mesoorganic templating agents R1 and R2; the silicon-aluminum oxide ratio (2x/y) is 25-100; the molecular sieve can be synthesized under ultra-low water content by introducing an organic template agent into a synthesized gel system, adding a guiding agent or a seed crystal, and simultaneously adopting F ions to replace partial Na ions as a mineralizer.

According to the method described herein, at least a portion of the alkali metal ions are replaced with a fluorine-containing reagent. Thus, some or all of the alkali metal ions in the resulting molecular sieve product are replaced by fluoride ions. The content of alkali metal elements in the fluorine-containing high-silicon Y molecular sieve according to the present application is low, even as low as 0, compared to the case where no fluorine-containing reagent is used.

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.

Unless otherwise specified, the raw materials and reagents in the examples of the present application were purchased commercially, wherein the Y zeolite having the FAU structure as the seed crystal was purchased from ziborun xin chemical technology ltd, and the ratio of silicon to aluminum oxide was 5; the EMT zeolite having an EMT structure was purchased from molecular sieves ltd of huanan world with a silica-alumina oxide ratio of 3.

The analysis method in the examples of the present application is as follows:

x-ray powder diffraction phase analysis (XRD) an X' Pert PRO X-ray diffractometer from pananace, netherlands, Cu target, K α radiation source (λ ═ 0.15418nm), voltage 40kV, current 40mA was used.

The elemental composition was determined using a Philips Magix 2424X-ray fluorescence Analyzer (XRF).

Analyzing the content of the organic template agent in the sample by adopting a TA Q-600 thermal analyzer, and heating from room temperature to 900 ℃ at the heating rate of 10 ℃/min.

Using nuclear magnetism of carbon: (¹³C MAS NMR) analysis of the ratio of two organic templating agents, carbon Nuclear magnetism (C-MAS NMR)¹³C MAS NMR) experiments were performed on a Bruker Avance III 600(14.1Tesla) spectrometer using a 4mm triple resonance probe, rotating at 12kHz, with amantadine as chemical shift reference, corrected to 0 ppm.

EXAMPLE 1 preparation of sample S1

Preparing a guiding agent A: 0.23g of sodium hydroxide (analytical grade, Mimeou chemical reagents Ltd., Tianjin, Kogyo, Ltd.) and 0.35g of sodium aluminate (chemical grade, Shanghai chemical reagents Co., Ltd., China medicine) were dissolved in 19.06g of tetramethylammonium hydroxide (25% aqueous solution, Aladdin chemical reagents Ltd., Shanghai) and stirred until they were clarified, and then 14.00g of ethyl orthosilicate (chemical grade, Shanghai chemical reagents Co., China medicine) was added dropwise thereto and stirred at room temperature for 2 hours. Standing the solution at 25 deg.C for 12 hr, and rotating and aging at 80 deg.C for 48 hr.

Preparation of synthetic gel C: 0.13g of sodium aluminate, 0.07g of sodium hydroxide are added to a solution of 10.84g of tetrapropylammonium hydroxide (25% by weight), stirred until clear, and 13.33g of silica Sol (SiO) are added dropwise₂: 30 wt%, Shenyang chemical Co., Ltd.) was stirred for 0.5h, and then added0.83g of hydrofluoric acid (40 wt%) was added, and 3.43g of the above directing agent was added and stirred for 3 hours.

The synthetic gel removed excess water: the resultant gel was heated at 60 ℃ to remove excess water, to give a dry powder mixture D10.88 g.

Synthesizing a fluorine-containing high-silicon Y molecular sieve: and transferring the dry powder mixture into a stainless steel reaction kettle, rotating and crystallizing for 5 days at 160 ℃, separating solid from liquid after crystallization is finished, washing to be neutral, and drying for 12 hours at 100 ℃ to obtain a sample S1.

The X-ray powder diffraction pattern (XRD) of sample S1 is shown in fig. 1, indicating that sample S1 is a molecular sieve having the FAU framework structure. Combining XRF, TG and¹³c MAS NMR analysis normalization yielded a sample S1 elemental composition: 0.03 F.0.01 Na.0.03R 1¹·0.16R2¹·(Si_0.967Al_0.032)O₂Wherein R1¹Is tetramethylammonium hydroxide, R2¹Is tetrapropylammonium hydroxide.

Example 2 preparation of sample S2

Preparing a guiding agent A: 1.03g of alumina (Shanghai chemical Co., Ltd., China medicine) was dissolved in 19.24g of tetraethylammonium hydroxide (25% aqueous solution, Allantin reagent, Ltd., Shanghai) and stirred until clarified, and 14.00g of ethyl orthosilicate (chemical purity, Shanghai chemical Co., Ltd., China medicine) was added dropwise thereto and stirred at room temperature for 2 hours. The solution was rotary aged at 75 ℃ for 36 h.

Preparation of synthetic gel C: 0.08g of sodium aluminate (Al)₂O₃：51wt％，Na₂O: 41 wt%, Tianjin photofabrication Co., Ltd.) was added to a solution of 4.71g tetraethylammonium hydroxide (25 wt%) and stirred until it was clear, and 13.33g of silica Sol (SiO) was added dropwise₂: 30 wt%, Shenyang chemical Co., Ltd.) was stirred for 0.5h, then 0.80g of hydrofluoric acid (40 wt%) was added, and 2.46g of the above directing agent was further added and stirred for 3 h.

The synthetic gel removed excess water: the resultant gel was heated at 60 ℃ to remove excess water, to give a dry powder mixture D8.21 g.

Synthesizing a fluorine-containing high-silicon Y molecular sieve: and transferring the dry powder mixture into a stainless steel reaction kettle, rotating and crystallizing for 3 days at 130 ℃, separating solid from liquid after crystallization is finished, washing to be neutral, and drying for 12 hours at 100 ℃ to obtain a sample S2.

The X-ray powder diffraction pattern (XRD) of sample S2 is close to that of fig. 1, indicating that sample S2 is a molecular sieve having a FAU framework structure. Combining XRF, TG and¹³c MAS NMR analysis normalized to give sample S2 with an elemental composition: 0.05 F.0 Na.0.04R 1²·0.06R2³·(Si_0.977Al_0.023)O₂Wherein R1²And R2³All are tetraethylammonium hydroxide.

EXAMPLE 3 preparation of samples S3-S30

The raw material types, molar ratios, crystallization conditions, water-silicon ratios and product crystal structures and compositions of samples S3-S30 are shown in Table 1, the aging temperature, time, aging mode and the addition amount of the directing agent are shown in Table 2, and the preparation process is the same as that of sample S1 in example 1.

Comparative example 1 preparation of comparative sample 1

The specific raw material types, molar ratios, blending processes and crystallization conditions were the same as those of sample S1 in example 1, except that no directing agent preparation step was used, and no directing agent was added in the subsequent gel synthesis preparation step. The resulting sample was designated comparative sample 1.

Comparative example 2 preparation of comparative sample 2

The specific raw material types, molar ratios, blending processes and crystallization conditions were the same as those of sample S1 in example 1, except that after the guiding agent preparation step was completed, the mixture was stirred at room temperature for 2 hours without aging. The resulting sample was designated comparative sample 2.

Comparative example 3 preparation of comparative sample 3

The specific raw material types, molar ratios, blending processes and crystallization conditions were the same as those of sample S1 in example 1, except that no fluorine-containing reagent was added during the initial gel preparation. The resulting sample was designated comparative sample 3.

XRD analysis of samples S1-S30 of example 3 and comparative samples 1-3

The phases of samples S1-S30 and comparative samples 1-3 were analyzed by X-ray diffraction.

The results show that samples S1-S30 prepared in examples 1 and 2 are both high purity and high crystallinity Y molecular sieves, which are typically represented by the XRD spectrum of sample S1 as in fig. 1. The XRD spectrum results of samples S2-S30 were close to those of fig. 1, i.e., diffraction peak positions and shapes were substantially the same, and relative peak intensities fluctuated within ± 5% depending on the changes in synthesis conditions, indicating that samples S1-S30 have the structural characteristics of Y-type zeolite and are free of heterocrystals.

XRD patterns of comparative sample 1, comparative sample 2 and comparative sample 3 are shown in fig. 2, fig. 3 and fig. 4, respectively. It can be seen that both comparative sample 1 and comparative sample 2 are amorphous, and it can be seen that the addition of the directing agent is necessary in the synthesis of the fluorine-containing high-silicon Y molecular sieve according to the present application, and the directing agent must be aged at high temperature in the preparation process to play a role in inducing crystallization, which is a key factor for synthesizing the fluorine-containing high-silicon Y molecular sieve. Comparative sample 3 is a molecular sieve of FAU structure, but XRF results indicate a product silica to alumina ratio of only 15, which indicates that the addition of a fluorine-containing reagent is also another important factor essential for the synthesis of high-silicon Y zeolite molecular sieves as described herein.

EXAMPLE 4 preparation of sample Y1

Preparing a synthetic gel: 0.20g of alumina (solids content 67.5%), 0.10g of sodium hydroxide are dissolved in 10.82g of tetrapropylammonium hydroxide (25% by weight) and stirred until clear, and 26.66g of silica Sol (SiO) are added dropwise₂: 30 wt%) was stirred for 1h, then 1.33g of hydrofluoric acid (40 wt%) was added dropwise, stirred for 0.5h until homogeneous, then 0.64g of EMT zeolite seed with a silica alumina ratio of 3 was added and stirred for 1 h.

The synthetic gel removed excess water: the resultant gel was heated at 60 ℃ to remove excess water, to give a dry powder mixture D16.97 g.

Synthesizing a fluorine-containing high-silicon Y molecular sieve: and transferring the dry powder mixture into a stainless steel reaction kettle, rotating and crystallizing for 4 days at 160 ℃, separating solid from liquid after crystallization is finished, washing to be neutral, and drying for 12 hours at 100 ℃ to obtain a sample Y1.

The X-ray powder diffraction pattern (XRD) of sample Y1 is shown in fig. 5, indicating that sample Y1 is a molecular sieve having the FAU framework structure. Combining XRF, TG and¹³c MAS NMR analysis normalized to give sample Y1 with an elemental composition: 0.02 F.0.01 Na. cndot0.06R2¹·(Si_0.97Al_0.03)O₂Wherein R2¹Is tetrapropylammonium hydroxide.

EXAMPLE 5 preparation of samples Y2-Y30

The types of raw materials, molar ratios, seed crystal addition amounts, crystallization conditions, water-silicon ratios, and crystal structures and compositions of the products of samples Y2-Y30 are shown in Table 3, and the compounding process was the same as that of sample Y1 in example 4.

Comparative example 4 preparation of comparative sample 4

The specific raw material types, molar ratios, blending processes and crystallization conditions were the same as those of sample Y1 in example 4, except that no seed crystal addition step was performed, and the obtained sample was designated as comparative sample 4.

Comparative example 5 preparation of comparative sample 5

The specific raw material types, molar ratios, seed crystal addition amounts, blending processes and crystallization conditions were the same as those of sample Y1 in example 4 except that no fluorine-containing reagent was added during the initial gel preparation process. The resulting sample was designated comparative sample 5.

XRD analysis of samples Y1-Y30 and comparative samples 4 and 5 of example 6

The phases of samples Y1-Y30 and comparative samples 4 and 5 were analyzed by X-ray diffraction.

The results show that samples Y1-Y30 prepared in examples 4 and 5 are both high purity and high crystallinity Y molecular sieves, which are typically represented by the XRD spectrum of sample Y1 as in fig. 5. The XRD spectrum results of samples Y2-Y30 were close to those of fig. 5, i.e., the diffraction peak positions and shapes were substantially the same, and the relative peak intensities fluctuated within ± 5% depending on the changes in synthesis conditions, indicating that samples Y1-Y30 have the structural characteristics of Y-type zeolite and are free of heterocrystals.

The XRD patterns of comparative sample 4 and comparative sample 5 are shown in fig. 6 and fig. 7, respectively. It can be seen that while comparative sample 4 is amorphous and comparative sample 5 is a FAU-structured molecular sieve, XRF results indicate a silica to alumina ratio of only 17, and it can be seen that in the synthesis of the fluorine-containing high-silicon Y molecular sieve according to the present application, the addition of the seed crystal and the addition of the fluorine-containing reagent are both necessary and critical to be able to synthesize the high-silicon Y zeolite molecular sieve as described herein.

TABLE 2S 1-S30 temperature, time, mode and amount of director aging

Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.

Claims

1. The preparation method of the fluorine-containing high-silicon Y molecular sieve is characterized in that the anhydrous chemical composition of the fluorine-containing high-silicon Y molecular sieve is shown as a formula I:

hF·kM·mR1·nR2·(Si_xAl_y)O₂formula I

Wherein F represents fluoride ion;

m is at least one selected from alkali metal elements;

r1 and R2 respectively represent organic templates;

h represents per mole (Si)_xAl_y)O₂H is 0.01 to 0.2;

x and y respectively represent mole fractions of Si and Al, 2x/y is 25-100, and x + y is 1;

the preparation method comprises the following steps:

b) removing water from the synthetic gel to obtain a dry powder mixture;

2. The method of claim 1, wherein M is at least one selected from the group consisting of sodium, potassium, and cesium.

3. The method for preparing the fluorine-containing high-silicon Y molecular sieve according to claim 1, wherein h is 0.01-0.15; k is 0-0.08; m is 0 or 0.01 to 0.1; n is 0.03 to 0.16.

4. The method for preparing the fluorine-containing high-silicon Y molecular sieve according to claim 1, wherein h is 0.02-0.1; k is 0.01 to 0.05; m is 0 or 0.02-0.05; n is 0.06 to 0.16.

5. The method of claim 1, wherein the fluorine-containing high-silicon Y molecular sieve is prepared by a method comprising

Then, the organic template R1 is selected from at least one quaternary ammonium compound having a structural formula shown in formula II:

6. The method for preparing fluorine-containing high-silicon Y molecular sieve according to claim 1, wherein the organic template R1 is at least one selected from tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide and tetrabutylammonium hydroxide.

7. The method for preparing fluorine-containing high-silicon Y molecular sieve according to claim 1, wherein the organic template R2 is at least one selected from quaternary ammonium compound and nitrogen-containing heterocyclic compound with the structural formula shown in formula III:

8. The method for preparing fluorine-containing high-silicon Y molecular sieve according to claim 7, wherein the nitrogen-containing heterocyclic compound is at least one selected from pyridine, piperidine, imidazole, piperazine and derivatives thereof.

9. The method of claim 1, wherein the organic templating agent R2 is selected from the group consisting of tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, tetrahexylammonium hydroxide, tetrapropylammonium bromide, tetrabutylammonium chloride, tetrapentylammonium bromide, tripropylisobutylammonium bromide, tributylcyclohexylammonium hydroxide, dibutyldihexylammonium hydroxide, choline, triethylhydroxyethylammonium hydroxide, tripropylhydroxyethylammonium hydroxide, tributylhydroxyethylammonium hydroxide, tributylbenzylammonium hydroxide, triethylbenzylammonium hydroxide, tripropylbenzylammonium hydroxide, triethyladamantylammonium chloride, tripropyladamantylammonium chloride, pyridine, N-methylpyridine, N-ethylpyridine, N-propylpyridine, N-butylpyridine, 1-ethyl-3-butylpyridine hydroxide, triethylbenzylammonium hydroxide, tripropyladamantylammonium chloride, pyridinium chloride, pyridine, N-methylpyridine, N-ethylpyridine, N-propylpyridine, N-butylpyridine, 1-ethyl-3-butylpyridine hydroxide, and mixtures thereof, 1-ethyl-2-propylpyridine hydroxide, piperidine, N-dimethylpiperidine, N-dimethyl-3, 5-diethylpiperidine hydroxide, N-dimethyl-3, 5-dipropylpiperidine hydroxide, N-diethyl-3, 5-dipropylpiperidine hydroxide, N-dimethyl-2, 6-dimethylpiperidine hydroxide, N-dimethyl-2, 6-diethylpiperidine hydroxide, imidazole, 1-ethyl-3-butylimidazole hydroxide, 1-ethyl-3-butyl-4-propylimidazole hydroxide, piperazine, N-methylpiperazine, 1, 4-dipropylpiperazine, 1-methyl-4-ethylpiperazine and 1-ethyl-4-butyl-5- At least one of methylpiperazines.

10. The method of claim 1, wherein the preparation of the directing agent comprises the steps of:

11. The method of claim 1, wherein the fluorine source is selected from at least one of hydrofluoric acid and ammonium fluoride.

12. The method of claim 1, wherein the silicon source in step a) and step a0) is independently selected from at least one of methyl orthosilicate, ethyl orthosilicate, silica sol, solid silica gel, silica white, and sodium silicate;

the aluminum sources in step a) and step a0) are independently selected from at least one of sodium metaaluminate, alumina, aluminum hydroxide, aluminum isopropoxide, aluminum 2-butoxide, aluminum chloride, aluminum sulfate, and aluminum nitrate;

the alkali metal source in step a) and step a0) is independently selected from at least one of sodium hydroxide, potassium hydroxide and cesium hydroxide.

13. The method of claim 1, wherein the silicoaluminophosphate molecular sieve seeds are zeolitic molecular sieves having the FAU or EMT structure.

14. The method of claim 1, wherein the aluminosilicate molecular sieve seed is selected from Na-type, NH-type₄At least one of type and H zeolite molecular sieves.

15. The method as claimed in claim 10, wherein in step a0), the aluminum source, the silicon source, the alkali metal source, the organic template R1 and the water are mixed according to the following molar ratio:

1SiO₂:(0.01～0.1)Al₂O₃:(0～0.1)M₂O:(0.1～2)R1:(10～20)H₂O；

wherein the mole number of the silicon source is SiO₂Counting; the mole number of the aluminum source is Al₂O₃Counting; the mole number of the organic template R1 is calculated by the mole number of R1 per se; the number of moles of alkali metal sourceMetal oxide M corresponding to alkali metal M₂And the mole number of O.

16. The method as claimed in claim 10, wherein the aging temperature in step a0) is 25-120 ℃.

17. The method as claimed in claim 10, wherein in step a0), the aging time is 0.5-3 days.

18. The method according to claim 10, characterized in that in step a0), the aging is performed in a dynamic or static manner.

19. The method according to claim 10, characterized in that in step a0), the aging is performed in a combination of dynamic and static manner.

20. The method of claim 1, wherein in step a), the aluminum source, the silicon source, the alkali metal source, the fluorine source, the organic template R2 and water are mixed in the following molar ratios:

21. The method according to claim 1, wherein in step a), the guiding agent is added in an amount such that the SiO in the guiding agent₂In an amount of SiO in the initial gel₂3-20 wt% of the content.

22. The process of claim 1, wherein in step a), the amount of the aluminosilicate molecular sieve seeds added is SiO in the initial gel₂3-20 wt% of the content.

23. The method according to claim 1, wherein the stirring is performed for 1 to 3 hours in step a).

24. The method of claim 1, wherein in step b), the synthetic gel is dewatered to H therein₂O and SiO₂The molar ratio of (a) to (b) is 1:1 to 3: 1.

25. The method according to claim 1, wherein in step b) the water removal is performed by evaporation by heating.

26. The method according to claim 25, wherein the temperature of the evaporation in step b) is 50-100 ℃.

27. The method according to claim 25, wherein in step b), the evaporation mode is static evaporation or stirring evaporation.

28. The method as claimed in claim 1, wherein the temperature of the crystallization in step c) is 100 to 180 ℃.

29. The method as claimed in claim 1, wherein the crystallization time in step c) is 0.5 to 10 days.

30. The process according to claim 1, wherein in step c) the crystallization is carried out in a dynamic or static manner.

31. The method according to claim 1, wherein in step c) the crystallization is performed in a combination of dynamic and static conditions.