ZSM-5@ Silicalite-1 type core-shell molecular sieve and preparation method and application thereof
阅读说明：本技术 一种ZSM-5@ Silicalite-1型核壳分子筛及其制备方法和应用 (ZSM-5@ Silicalite-1 type core-shell molecular sieve and preparation method and application thereof ) 是由 李俊杰 沈宏宇 李秀杰 朱向学 谢素娟 陈福存 刘珍妮 郭英杰 王玉忠 楚卫锋 于 2020-06-01 设计创作，主要内容包括：本发明公开了一种ZSM-5@Silicalite-1型核壳分子筛及其制备方法和应用,属于催化领域。其特征在于,所述方法至少包括：(1)将含有铝源、硅源、调节物、Silicalite-1晶种的原料,晶化I,得到中间产物；(2)向所述中间产物中加入模板剂,晶化II,得到所述ZSM-5@Silicalite-1型核壳分子筛；在所述步骤(1)中,所述调节物选自酸源、碱源中的至少一种。本申请提供的方法不需添加ZSM-5晶核,以廉价硅溶胶等为硅源,一锅法就可制备得到ZSM-5@Silicalite-1(ZSM-5@S-1)核壳材料,且不受合成体系中H-(2)O/SiO-(2)的限制,所制备的ZSM-5@S-1材料晶体规整均一。(The invention discloses a ZSM-5@ Silicalite-1 type core-shell molecular sieve, and a preparation method and application thereof, and belongs to the field of catalysis. Characterized in that the method at least comprises: (1) crystallizing I a raw material containing an aluminum source, a silicon source, a modifier and a Silicalite-1 seed crystal to obtain an intermediate product; (2) adding a template agent into the intermediate product, and crystallizing II to obtain the ZSM-5@ Silicalite-1 type core-shell molecular sieve; in the step (1), the modifier is at least one selected from an acid source and an alkali source. According to the method provided by the application, ZSM-5@ Silicalite-1(ZSM-5@ S-1) core-shell material can be prepared by a one-pot method without adding ZSM-5 crystal nucleus and taking cheap silica sol and the like as silicon sources, and the ZSM-5@ Silicalite-1(ZSM-5@ S-1) core-shell material is not subjected to H in a synthesis system 2 O/SiO 2 The prepared ZSM-5@ S-1 material has regular and uniform crystals.)
1. A preparation method of a [email protected] Silicalite-1 type core-shell molecular sieve is characterized by at least comprising the following steps:
(1) crystallizing I a raw material containing an aluminum source, a silicon source, a modifier and a Silicalite-1 seed crystal to obtain an intermediate product;
(2) adding a template agent into the intermediate product, and crystallizing II to obtain the [email protected] Silicalite-1 type core-shell molecular sieve;
in the step (1), the modifier is at least one selected from an acid source and an alkali source.
2. The method according to claim 1, wherein the crystallization I conditions are as follows: the crystallization temperature is 120-250 ℃; the crystallization time is 1-24 h; and/or the presence of a gas in the gas,
the crystallization II conditions are as follows: the crystallization temperature is 100-200 ℃; the crystallization time is 2-120 h;
preferably, the conditions of crystallization I are: the crystallization temperature is 180-240 ℃; the crystallization time is 1-24 h.
3. The preparation method according to claim 1, wherein in the step (1), the silicon source is at least one selected from silica sol, water glass, silica gel and white carbon black; and/or the presence of a gas in the gas,
the aluminum source is at least one selected from sodium metaaluminate, aluminum nitrate, aluminum sulfate and aluminum chloride.
4. The preparation method according to claim 3, wherein in the step (1), the mass ratio of the Silicalite-1 seed crystal to the silicon source is 0.01 to 0.3;
wherein the mass of the Silicalite-1 seed crystal is SiO contained in the Silicalite-1 seed crystal2A mass meter;
the silicon source is SiO2The mass meter of (1).
5. The method according to claim 3, wherein the molar ratio of the silicon source to the aluminum source is 30 to 200;
wherein the mole number of the silicon source is SiO2In terms of moles;
the mole number of the aluminum source is Al2O3In moles of (a).
6. The production method according to claim 1, wherein in the step (1), the acid source is selected from at least one of sulfuric acid, hydrochloric acid, nitric acid; and/or the presence of a gas in the gas,
the alkali source comprises a metal-containing alkali source; the alkali source is selected from sodium hydroxide;
preferably, the molar ratio of the regulator to the silicon source is 0.1-0.6;
wherein the mole number of the silicon source is SiO2In terms of moles;
the number of moles of the acid source is based on the number of moles of the acid source itself;
the number of moles of the alkali source is calculated by the number of moles of the metal-containing oxide;
preferably, in the step (1), the raw material further contains water; the molar ratio of the water to the silicon source is 10-80;
wherein the moles of water are based on the moles of water itself;
the mole number of the silicon source is SiO2In terms of moles;
preferably, in the step (2), the template is selected from at least one of tetrapropylammonium hydroxide, tetrapropylammonium bromide, n-butylamine, and 1, 6-hexamethylenediamine.
7. The preparation method according to claim 6, wherein in the step (2), the molar ratio of the template to the silicon source is 0.02 to 2.00;
wherein the mass of the template is calculated by the mole number of the template;
the mole number of the silicon source is SiO2In moles of (a).
8. A [email protected] Silicalite-1 type core-shell molecular sieve, which is characterized in that the [email protected] Silicalite-1 type core-shell molecular sieve is selected from any one of the [email protected] Silicalite-1 type core-shell molecular sieves prepared by the method according to any one of claims 1 to 7.
9. The [email protected] Silicalite-1 type core-shell molecular sieve of claim 8, wherein the [email protected] Silicalite-1 type core-shell molecular sieve comprises a core phase ZSM-5 molecular sieve and a shell phase Silicalite-1 molecular sieve;
the [email protected] Silicalite-1 type core-shell molecular sieve is a monodisperse molecular sieve crystal with an MFI topological structure; the grain size is 0.2 to 5 μm.
10. Use of the [email protected] Silicalite-1 type core-shell molecular sieve prepared according to any of claims 1 to 7, or the [email protected] Silicalite-1 type core-shell molecular sieve according to claim 8 or 9 as a catalyst in benzene and ethylene alkylation, toluene disproportionation, xylene isomerization, low carbon aromatization, methanol to propylene, methanol to gasoline reactions.
Technical Field
The invention relates to a [email protected] Silicalite-1 type core-shell molecular sieve, and a preparation method and application thereof, and belongs to the field of catalysis.
Background
The MFI molecular sieve is a medium pore zeolite with two-dimensional crossed ten-member ring channels, one dimension of which is a ten-member ring straight channel, and the other dimension of which is a ten-member ring channel with a Zigzag shape. The pore channel structure parallel to the [ 100 ] direction is 0.51nm multiplied by 0.55 nm; the channel structure parallel to [ 010 ] direction was 0.53nm × 0.56 nm. The ZSM-5 type molecular sieve is one of the most important molecular sieve catalytic materials at present, and is applied to a plurality of reaction processes such as benzene and ethylene alkylation, toluene disproportionation, xylene isomerization, low-carbon hydrocarbon aromatization, methanol-to-propylene, methanol-to-gasoline and the like on a large scale.
However, in the reactions of methanol conversion, low-carbon hydrocarbon aromatization and the like, the ZSM-5 catalyst still faces the problem of rapid carbon deposition and inactivation, and particularly, the acid sites on the outer surface of the ZSM-5 cause non-selective carbon deposition reaction on the outer surface, so that the orifice is blocked, and finally the catalyst is inactivated. In addition, in shape selective catalytic reactions such as toluene methanol alkylation, toluene disproportionation, xylene isomerization, etc., the acidic sites on the outer surface tend to cause a decrease in selectivity to para-product.
The Silicalite-1 is epitaxially grown on the surface of the ZSM-5 to obtain the [email protected] Silicalite-1([email protected] S-1) core-shell material, so that the acid sites on the outer surface can be effectively passivated, the material has higher para-selectivity in shape-selective catalytic reactions such as toluene methanol alkylation, toluene disproportionation, xylene isomerization and the like, carbon deposition on the outer surface of the catalyst can be avoided to block microporous channels, and the catalytic stability is improved. However, at present, an organic template agent is required to be added in the process of preparing the [email protected] S-1 core-shell material, in order to avoid the independent nucleation of silicon species in a synthesis system under the guiding action of the organic template agent, the synthesis system generally adopts higher H2O/SiO2(close to 200) to reduce the supersaturation of the solution, inhibit the nucleation process, result in very low yields, while producing large amounts of wastewaterAt present, the method is not applied to industrial production. Adding NH into the synthesis system4F can also inhibit the nucleation process, but also has the problem of treating fluorine-containing wastewater. In addition, as silicon sources such as silica sol contain aluminum impurity, the adopted silicon sources are tetraethoxysilane, the cost is high, and alcohols generated by hydrolysis are not beneficial to safe production.
Disclosure of Invention
Aiming at the defects that the traditional method for synthesizing the [email protected] S-1 core-shell material in the prior art has higher preparation cost, higher requirement on the ZSM-5 crystal nucleus quality, extremely low single-kettle yield and poor product repeatability, limits large-scale industrial production and the like, the invention provides a method for combining template-free pre-crystallization and organic template-assisted crystallization, wherein the ZSM-5 crystal nucleus is not required to be added, cheap silica sol and the like are used as silicon sources, the [email protected] S-1 core-shell material can be prepared by a one-pot method, and the H can be greatly reduced by the method2O/SiO2The ratio is below 40, the single kettle yield is improved, and regular, uniform and monodisperse particles are prepared.
The preparation method provided by the application is simple and cheap, does not need to add ZSM-5 crystal nucleus, takes cheap silica sol and the like as silicon sources, can prepare the [email protected] S-1 core-shell material by a one-pot method, and is not subject to H in a synthesis system2O/SiO2The prepared [email protected] S-1 material has regular and uniform crystals.
According to a first aspect of the present application, there is provided a process for preparing a [email protected] Silicalite-1 type core-shell molecular sieve, the process at least comprising:
(1) crystallizing I a raw material containing an aluminum source, a silicon source, a modifier and a Silicalite-1 seed crystal to obtain an intermediate product;
(2) adding a template agent into the intermediate product, and crystallizing II to obtain the [email protected] Silicalite-1 type core-shell molecular sieve;
in the step (1), the modifier is at least one selected from an acid source and an alkali source.
Optionally, the conditions for crystallization I are: the crystallization temperature is 120-250 ℃; the crystallization time is 1-24 h; and/or the presence of a gas in the gas,
the crystallization II conditions are as follows: the crystallization temperature is 100-200 ℃; the crystallization time is 2-120 h.
Preferably, the conditions of crystallization I are: the crystallization temperature is 180-240 ℃; the crystallization time is 1-24 h.
Optionally, the upper temperature limit of crystallization I is independently selected from 250 ℃, 200 ℃, 150 ℃, 130 ℃, and the lower temperature limit is independently selected from 120 ℃, 200 ℃, 150 ℃, 130 ℃.
Optionally, the upper time limit of crystallization I is independently selected from 24h, 20h, 16h, 12h, 8h, 4h, and the lower time limit is independently selected from 1h, 20h, 16h, 12h, 8h, 4 h.
Optionally, the upper temperature limit of crystallization II is independently selected from 200 ℃, 180 ℃, 160 ℃, 140 ℃, 120 ℃, and the lower temperature limit is independently selected from 100 ℃, 180 ℃, 160 ℃, 140 ℃, 120 ℃.
Optionally, the upper time limit of crystallization II is independently selected from 120h, 100h, 80h, 60h, 40h, 20h, 10h, 5h, and the lower time limit is independently selected from 2h, 100h, 80h, 60h, 40h, 20h, 10h, 5 h.
Optionally, in the step (1), the silicon source is selected from at least one of silica sol, water glass, silica gel and silica white; and/or the presence of a gas in the gas,
the aluminum source is at least one selected from sodium metaaluminate, aluminum nitrate, aluminum sulfate and aluminum chloride.
Optionally, in the step (1), the mass ratio of the Silicalite-1 seed crystal to the silicon source is 0.01-0.3;
wherein the mass of the Silicalite-1 seed crystal is SiO contained in the Silicalite-1 seed crystal2A mass meter;
the silicon source is SiO2The mass meter of (1).
Alternatively, in step (1), the mass ratio of the Silicalite-1 seed crystal to the silicon source has an upper limit independently selected from 0.3, 0.2, 0.1, 0.08, 0.06, 0.04, 0.02 and a lower limit independently selected from 0.01, 0.2, 0.1, 0.08, 0.06, 0.04, 0.02.
Optionally, the molar ratio of the silicon source to the aluminum source is 30-200;
wherein the mole number of the silicon source is SiO2In terms of moles;
the mole number of the aluminum source is Al2O3In moles of (a).
Alternatively, the upper limit of the molar ratio of the silicon source to the aluminum source is independently selected from 200, 150, 100, 80, 50, 40, and the lower limit is independently selected from 30, 150, 100, 80, 50, 40.
Optionally, in the step (1), the acid source is selected from at least one of sulfuric acid, hydrochloric acid and nitric acid; and/or the presence of a gas in the gas,
the alkali source comprises a metal-containing alkali source; the alkali source is selected from sodium hydroxide.
Optionally, the molar ratio of the modifier to the silicon source is 0.1-0.6;
wherein the mole number of the silicon source is SiO2In terms of moles;
the number of moles of the acid source is based on the number of moles of the acid source itself;
the number of moles of the alkali source is based on the number of moles of the metal-containing oxide.
Preferably, the moles of sodium hydroxide are based on the moles of sodium oxide.
Alternatively, the molar ratio of the modifier to the silicon source has an upper limit independently selected from 0.6, 0.5, 0.4, 0.3, 0.2 and a lower limit independently selected from 0.1, 0.5, 0.4, 0.3, 0.2.
Optionally, in the step (1), the raw material further contains water; the molar ratio of the water to the silicon source is 10-80;
wherein the moles of water are based on the moles of water itself;
the mole number of the silicon source is SiO2In moles of (a).
Alternatively, the upper limit of the molar ratio of the water to the silicon source is independently selected from 80, 60, 40, 20 and the lower limit is independently selected from 10, 60, 40, 20.
Specifically, water is used as a solvent in the present application, and an organic solvent is not included in the reaction of step (1) in the present application.
According to the preparation method provided by the application, in the presence of solvent water, a core-shell structure with a ZSM-5 molecular sieve as a core and a Silicalite-1 molecular sieve as a shell is formed.
Optionally, in the step (2), the templating agent is selected from at least one of tetrapropylammonium hydroxide (TPAOH), tetrapropylammonium bromide (TPABr), n-butylamine, 1, 6-hexanediamine.
Optionally, in the step (2), the molar ratio of the template to the silicon source is 0.02-2.00;
wherein the mass of the template is calculated by the mole number of the template;
the mole number of the silicon source is SiO2In moles of (a).
Alternatively, the upper limit of the molar ratio of the templating agent and the silicon source is independently selected from 2, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.4, 0.1, 0.08, 0.06, 0.04, and the lower limit is independently selected from 0.02, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.4, 0.1, 0.08, 0.06, 0.04.
According to the second aspect of the application, the [email protected] Silicalite-1 type core-shell molecular sieve is further provided, and the [email protected] Silicalite-1 type core-shell molecular sieve is selected from any one of the [email protected] Silicalite-1 type core-shell molecular sieves prepared according to the method.
Alternatively, the [email protected] Silicalite-1 type core-shell molecular sieve comprises a core phase ZSM-5 molecular sieve and a shell phase Silicalite-1 molecular sieve;
the [email protected] Silicalite-1 type core-shell molecular sieve is a monodisperse molecular sieve crystal with an MFI topological structure; the grain size is 0.2 to 5 μm.
Alternatively, the upper size limit of the grains is independently selected from 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.8 μm, 0.5 μm, and the lower limit is independently selected from 0.2 μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.8 μm, 0.5 μm.
According to the third aspect of the application, the [email protected] Silicalite-1 type core-shell molecular sieve prepared by the method and the application of the [email protected] Silicalite-1 type core-shell molecular sieve in benzene and ethylene alkylation reaction, toluene disproportionation reaction, xylene isomerization reaction, low-carbon hydrocarbon aromatization reaction, methanol-to-propylene reaction and methanol-to-gasoline reaction are provided.
Optionally, the morphology of the [email protected] Silicalite-1 type core-shell molecular sieve in the application can be regulated and controlled by adjusting the raw material ratio and the crystallization condition, the [email protected] Silicalite-1 type core-shell molecular sieve is a monodisperse MFI zeolite crystal, the morphology is regular and uniform, and the outer surface of the [email protected] Silicalite-1 type core-shell molecular sieve is almost free of aluminum.
As a specific implementation mode, the method solves the problems that a [email protected] S-1 core-shell material prepared by a traditional synthesis method is high in preparation cost, high in requirements for ZSM-5 crystal nucleus quality, low in single-kettle yield and poor in product repeatability, large-scale industrial production of the material is limited and the like through the following technical scheme. The method comprises the following specific steps:
1) slowly adding a silicon source, an aluminum source, inorganic base (or inorganic acid), deionized water and seed crystal into a reaction kettle in a certain sequence under stirring to form a raw material mixture A, fully stirring to uniformly mix the raw material mixture A, and dynamically crystallizing at the high temperature of 100-250 ℃ for 1-24 hours;
2) and cooling the reaction kettle by using tap water, adding a template agent, after uniformly mixing, dynamically crystallizing the mixture at 100-200 ℃ for 2-120 h, and carrying out hydrothermal preparation to obtain the [email protected] S-1 core-shell material.
The template agent is at least one of n-butylamine and 1, 6-hexamethylene diamine. The seed crystal is Silicalite-1.
Through an ion exchange technology, sodium ions in the [email protected] S-1 core-shell material synthesized by the method can be replaced by other cations, and a hydrogen type sample is obtained after roasting, so that the hydrogen type sample can be applied to different catalytic reaction processes. The [email protected] S-1 core-shell material prepared by the invention can be used in the reaction processes of methanol conversion, toluene methanol alkylation, toluene disproportionation, xylene isomerization and the like, but is not limited to the reaction processes.
The beneficial effects that this application can produce include:
the method solves the problems that the cost for preparing the [email protected] S-1 core-shell material by the traditional synthesis method is high, the requirement on the quality of the ZSM-5 crystal nucleus is high, the single-kettle yield of the traditional method is extremely low, the repeatability of the product is poor, the large-scale industrial production is limited, and the like.
Drawings
FIG. 1 is an X-ray diffraction pattern of the sample of example 1.
FIG. 2 is a SEM photograph of a sample of example 1.
FIG. 3 is an X-ray photoelectron spectrum of the sample of example 1.
Detailed Description
The present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.
Unless otherwise specified, the raw materials and reagents in the examples of the present invention were purchased from commercial sources,
the analysis method in the examples of the present invention is as follows:
x-ray diffraction pattern analysis (XRD) was performed using SmartLab 9.
X-ray photoelectron spectroscopy was performed using ESCALAB 250.
SEM morphology analysis was performed using a S-5500 scanning electron microscope.
Example 1:
the raw materials used were as follows:
A. silica sol
B. Aluminium sulphate
C. Sodium hydroxide
D. Tetrapropylammonium bromide
Silicalite-1 liquid seed crystals
Under the condition of stirring, adding silica sol, aluminum sulfate, sodium hydroxide, deionized water and Silicalite-1 liquid crystal seeds into a reaction kettle in a certain sequence, wherein the molar composition of a raw material mixture is as follows: SiO 22/Al2O3＝100，Na2O/SiO20.29, Seed (Silicalite-1 Seed)/SiO20.08 (mass ratio), H2O/SiO243. Stirring uniformly, placing in a crystallization kettle, and dynamically crystallizing at 210 ℃ for 4 h; quench the reaction with tap water and then add TPABr (TPAB)r/SiO20.15), crystallizing at 170 ℃ for 72 hours, cooling to room temperature, washing to be neutral by deionized water, and drying at 120 ℃ overnight to obtain the molecular sieve raw powder. FIG. 1 is a powder X-ray diffraction pattern of a [email protected] S-1 core-shell material, which can be seen to have a typical MFI topology without other hetero-phases. FIG. 2 is a scanning electron micrograph of a [email protected] S-1 sample showing regular morphology and uniform size. FIG. 3 is a photoelectron spectrum of a [email protected] S-1 core-shell material and a ZSM-5 standard sample, and shows that the outer surface of the obtained sample is almost free of aluminum, and the grain size of the obtained molecular sieve is about 500 nm.
Example 2:
the raw materials used were as follows:
A. white carbon black
B. Aluminium nitrate
C. Sodium hydroxide
D. Tetrapropylammonium hydroxide
Solid seed crystals of Silicalite-1
Under the condition of stirring, adding white carbon black, aluminum nitrate, sodium hydroxide, deionized water and Silicalite-1 solid crystal seeds into a reaction kettle in a certain sequence, wherein the molar composition of a raw material mixture is as follows: SiO 22/Al2O3＝60，Na2O/SiO2＝0.20，Seed/SiO20.04 (mass ratio), H2O/SiO230. Dynamic crystallizing at 180 deg.C for 10h, quenching with tap water, and adding TPAOH (TPAOH/SiO)20.10), crystallizing at 170 ℃ for 24 hours, cooling to room temperature, washing to be neutral by deionized water, and drying at 120 ℃ overnight to obtain the molecular sieve raw powder, wherein the grain size of the obtained molecular sieve particles is about 200 nm.
Example 3:
the raw materials used were as follows:
A. water glass
B. Aluminium trichloride
C. Hydrochloric acid solution
D. N-butylamine
Silicalite-1 liquid seed crystals
Under the condition of stirring, adding water glass, aluminium trichloride, hydrochloric acid solution, deionized water and liquidThe Silicalite-1 seed crystal is added into the reaction kettle in a certain sequence. The molar composition of the raw material mixture is: SiO 22/Al2O3＝120，Na2O/SiO2＝0.25，H2O/SiO2＝80，Seed/SiO20.16 (mass ratio). Dynamic crystallization is carried out for 24h at 140 ℃, tap water is used for quenching reaction, and then n-butylamine (n-butylamine/SiO) is added20.25), crystallizing at 170 ℃ for 48 hours, cooling to room temperature, washing to be neutral by deionized water, and drying at 120 ℃ overnight to obtain the molecular sieve raw powder, wherein the grain size of the obtained molecular sieve particles is about 2 mu m.
Example 4:
the raw materials used were as follows:
A. silica sol
B. Aluminium trichloride
C. Sodium hydroxide
1, 6-hexanediamine
Solid seed crystals of Silicalite-1
Under the condition of stirring, adding silica sol, aluminum trichloride, NaOH, deionized water and Silicalite-1 seed crystal into a reaction kettle in a certain sequence, wherein the molar composition of a raw material mixture is as follows: SiO 22/Al2O3＝200，Na2O/SiO2＝0.40，H2O/SiO2＝40，Seed/SiO20.02 (mass ratio). Dynamic crystallization at 240 deg.C for 1h, quenching with tap water, and adding 1, 6-hexamethylenediamine (1, 6-hexamethylenediamine/SiO)20.18), crystallizing at 120 ℃ for 48 hours, cooling to room temperature, washing to be neutral by deionized water, and drying at 120 ℃ overnight to obtain the molecular sieve raw powder, wherein the grain size of the obtained molecular sieve particles is about 3 mu m.
Example 5:
the raw materials used were as follows:
A. solid silica gel;
B. aluminium sulphate
C. Sodium hydroxide
D. Tetrapropylammonium hydroxide and tetrapropylammonium bromide
Silicalite-1 liquid seed crystals
Under the condition of stirring, silica gel, aluminum sulfate and N are addedadding the aOH, deionized water and Silicalite-1 liquid seed crystal into a reaction kettle in a certain sequence, wherein the molar composition of a raw material mixture is as follows: SiO 22/Al2O3＝80，Na2O/SiO2＝0.20，H2O/SiO2＝50，Seed/SiO20.08 (mass ratio). Dynamic crystallizing at 200 deg.C for 5h, quenching with tap water, adding TPAOH solution and TPABr (TPA)+/SiO20.20), crystallizing at 200 ℃ for 36h, cooling to room temperature, washing to be neutral by deionized water, and drying at 120 ℃ overnight to obtain the molecular sieve raw powder, wherein the grain size of the obtained molecular sieve particles is 5 mu m.
Example 6:
the raw materials used were as follows:
A. silica sol;
B. aluminium sulphate
C. Sodium hydroxide
D. Tetrapropylammonium bromide
Silicalite-1 liquid seed crystals
Under the condition of stirring, adding silica sol, aluminum sulfate, NaOH, deionized water and Silicalite-1 liquid crystal seeds into a reaction kettle, wherein the molar composition of a raw material mixture is as follows: SiO 22/Al2O3＝80，Na2O/SiO2＝0.40，H2O/SiO2＝30，Seed/SiO20.30 (mass ratio). Dynamic crystallizing at 180 deg.C for 2h, quenching with tap water, and adding TPABr (TPABr/SiO)20.02), crystallizing at 100 ℃ for 120h, cooling to room temperature, washing to neutrality by deionized water, and drying at 120 ℃ overnight to obtain the molecular sieve raw powder. The molecular sieve particle size is about 120 nm.
Example 7:
the raw materials used were as follows:
A. silica sol;
B. aluminium sulphate
C. Sodium hydroxide
D. Tetrapropylammonium bromide
Silicalite-1 liquid seed crystals
Under the condition of stirring, adding silica sol, aluminum sulfate, NaOH, deionized water andadding Silicalite-1 liquid seed crystal into a reaction kettle, wherein the molar composition of a raw material mixture is as follows: SiO 22/Al2O3＝80，Na2O/SiO2＝0.10，H2O/SiO2＝20，Seed/SiO20.10 (mass ratio). Dynamic crystallizing at 180 deg.C for 2h, quenching with tap water, and adding TPABr (TPABr/SiO)20.02), crystallizing at 140 ℃ for 96 hours, cooling to room temperature, washing to be neutral by deionized water, and drying at 120 ℃ overnight to obtain the molecular sieve raw powder. The molecular sieve particle size is about 800 nm.
The above description is only for the purpose of illustrating the present invention and is not intended to limit the present invention in any way, and the present invention is not limited to the above description, but rather should be construed as being limited to the scope of the present invention.