阅读说明：本技术 一种快速合成介孔sapo-11分子筛的方法 (Method for rapidly synthesizing mesoporous SAPO-11 molecular sieve ) 是由 王龙 陈文勇 石倩翡 苗植平 许振甫 徐辰 李阳 于 2020-12-21 设计创作，主要内容包括：本发明属于催化剂活性组分制备技术领域,具体涉及一种快速合成介孔SAPO-11分子筛的方法,在密封压力容器内混合水、模板剂、表面活性剂及助剂,然后补加至高温的磷、铝、硅均相凝胶中。高温下加入模板剂混合液,能够避开系统粘稠状态,避免形成凝胶块,有利于发挥模板剂和表面活性剂的作用。而高温磷、铝、硅均相凝胶遇到低温模板剂混合液,有利于形成介孔结构。本发明得到的SAPO-11分子筛具有介孔结构,产品还具有结晶度高、比表面积高的特点。同时,该技术方案还具备原材料利用率高,合成速度快的特点。本发明制备得到的介孔SAPO-11分子筛产品可以用作加氢异构化催化剂的活性组分,还可以作为甲醇制烯烃催化剂的活性组分。(The invention belongs to the technical field of preparation of active components of catalysts, and particularly relates to a method for quickly synthesizing a mesoporous SAPO-11 molecular sieve. The template agent mixed solution is added at high temperature, so that the system can be kept from a viscous state, gel blocks are prevented from being formed, and the effects of the template agent and the surfactant can be favorably exerted. And the high-temperature phosphorus, aluminum and silicon homogeneous gel meets the low-temperature template agent mixed solution, so that a mesoporous structure is formed. The SAPO-11 molecular sieve obtained by the invention has a mesoporous structure, and the product also has the characteristics of high crystallinity and high specific surface area. Meanwhile, the technical scheme also has the characteristics of high utilization rate of raw materials and high synthesis speed. The mesoporous SAPO-11 molecular sieve product prepared by the method can be used as an active component of a hydroisomerization catalyst and can also be used as an active component of a catalyst for preparing olefin from methanol.)

1. A method for rapidly synthesizing a mesoporous SAPO-11 molecular sieve is characterized by comprising the following steps: the method comprises the following steps:

a) sequentially dispersing an aluminum source, a phosphorus source and a silicon source in deionized water and uniformly stirring to prepare homogeneous gel, wherein the molar ratio of each component in the homogeneous gel is H₂O:Al₂O₃:P₂O₅:SiO₂＝20～100:1:0.5～2:0.1～1；

b) Loading the homogeneous gel into a reaction kettle for primary crystallization;

c) preparing a template agent, a surfactant and an auxiliary agent into a mixed solution in water, storing the mixed solution in a sealed pressure container, keeping the temperature at 20-100 ℃, wherein the molar ratio of each component in the mixed solution is H₂O, R, C and S are 1-10: 1: 0.01-1: 0-1, wherein R is a template agent, C is a surfactant and S is an auxiliary agent;

d) adding the mixed solution in the step c) into the reaction kettle in the step b) by using a high-pressure pump, wherein the molar ratio of each component in the kettle is H₂O:Al₂O₃:P₂O₅:SiO₂:R:C:S＝20～100:1:0.5～2:0.1～1:0.5～2:0.01～1:0～1；

e) Performing secondary crystallization;

f) and e) after the step e) is finished, removing mother liquor from the crystallized product, washing, drying and roasting to obtain the SAPO-11 molecular sieve.

2. The method for rapidly synthesizing the mesoporous SAPO-11 molecular sieve according to claim 1, wherein: the aluminum source in the step a) is one of pseudo-boehmite, aluminum isopropoxide or aluminum hydroxide; the phosphorus source is phosphoric acid solution; the silicon source is one of ethyl orthosilicate, silica gel, silica sol or white carbon black.

3. The method for rapidly synthesizing the mesoporous SAPO-11 molecular sieve according to claim 1, wherein: and c), stirring and crystallizing for 1-24 hours at the temperature of 60-165 ℃ in the step b) by using a high-pressure reaction kettle with stirring.

4. The method for rapidly synthesizing the mesoporous SAPO-11 molecular sieve according to claim 1, wherein: in the step c), the template agent is di-n-propylamine, diisopropylamine or a mixture of the di-n-propylamine and the diisopropylamine; the surfactant is cetyl trimethyl ammonium bromide or n-hexadecylamine; the auxiliary agent is oil-water amphiphilic organic matter.

5. The method for rapidly synthesizing the mesoporous SAPO-11 molecular sieve according to claim 4, wherein: the oil-water amphiphilic organic matter is one of ethanol, butanol, isopropanol, ether or acetone.

6. The method for rapidly synthesizing the mesoporous SAPO-11 molecular sieve according to claim 1, wherein: the initial temperature of the mixed liquid pumped into the reaction kettle in the step d) is 40 ℃ or more lower than the temperature of homogeneous gel in the reaction kettle.

7. The method for rapidly synthesizing the mesoporous SAPO-11 molecular sieve according to claim 1, wherein: the secondary crystallization in the step e) is carried out at the temperature of 170-200 ℃ for 12-24 hours by stirring.

Technical Field

The invention belongs to the technical field of preparation of active components of catalysts, and particularly relates to a method for quickly synthesizing a mesoporous SAPO-11 molecular sieve.

Background

The SAPO-11 molecular sieve has unique one-dimensional ten-membered ring straight hole channels (0.39nm multiplied by 0.63nm) and has an MEL topological structure. Due to the proper pore structure and acidity, the SAPO-11 molecular sieve shows excellent catalytic performance in a hydroisomerization catalytic reaction, and shows the characteristic of producing more isobutene in a methanol-to-olefin reaction (refer to CN108014846B specifically).

The traditional preparation method of the SAPO-11 molecular sieve mainly comprises the methods described in patents USP4440871, USP4701485 and the like. Pseudo-boehmite is taken as an aluminum source, phosphoric acid is taken as a phosphorus source, acidic silica sol is taken as a silicon source, and di-n-propylamine and diisopropylamine are taken as template agents. The traditional technical scheme has poor repeatability and long consumed time. And a silicon island region is easily formed on the structure, and an aggregate or a crystal with a larger grain diameter is easily formed on the appearance, so that the application and the industrial production of the SAPO-11 molecular sieve are restricted.

According to the definition of the International Union of Pure and Applied Chemistry (IUPAC), porous materials can be classified into the following three classes according to their pore diameters: the material with the pore diameter less than 2nm is microporous material; the material with the pore diameter between 2 and 50nm is mesoporous material (mesoporous materials); materials with pore sizes larger than 50nm are macroporous materials (macroporous materials). SAPO-11 molecular sieve has pore diameters below 2nm and is therefore classified as a microporous material. Since the SAPO-11 molecular sieve belongs to a microporous molecular sieve, large grains or aggregates are easily formed in the synthesis process. The diffusion of reactants and products is severely limited, the increase of byproducts and carbon deposition is caused, and the improvement of the reaction activity is hindered. To address diffusion limitations, mesopores are introduced into the microporous molecular sieve crystals. The microporous molecular sieve with the mesoporous structure can be beneficial to the diffusion of reactants and products, and even if the microporous molecular sieve is aggregate or large crystal particles, the diffusion performance is still excellent. The improvement of the diffusion performance also greatly improves the reaction performance, reduces the occurrence of side reactions and improves the activity of the catalyst. In the synthesis period, shortening the crystallization time improves the yield in the unit period, saves energy consumption, and is beneficial to greatly reducing the manufacturing cost and improving the productivity.

Therefore, the development of a technical scheme for rapidly synthesizing the mesoporous SAPO-11 molecular sieve is of great significance.

Disclosure of Invention

The invention aims to provide a method for quickly synthesizing a mesoporous SAPO-11 molecular sieve, which has the characteristics of high utilization rate of raw materials and high synthesis speed.

The invention relates to a method for quickly synthesizing a mesoporous SAPO-11 molecular sieve, which is characterized by comprising the following steps: the method comprises the following steps:

a) sequentially dispersing an aluminum source, a phosphorus source and a silicon source in deionized water and uniformly stirring to prepare homogeneous gel, wherein the molar ratio of each component in the homogeneous gel is H₂O:Al₂O₃:P₂O₅:SiO₂＝20～100:1:0.5～2:0.1～1；

b) Loading the homogeneous gel into a reaction kettle for primary crystallization;

c) preparing a template agent, a surfactant and an auxiliary agent into a mixed solution in water, storing the mixed solution in a sealed pressure container, keeping the temperature at 20-100 ℃, wherein the molar ratio of each component in the mixed solution is H₂O, R, C and S are 1-10: 1: 0.01-1: 0-1, wherein R is a template agent, C is a surfactant and S is an auxiliary agent;

d) adding the mixed solution in the step c) into the reaction kettle in the step b) by using a high-pressure pump, wherein the molar ratio of each component in the kettle is H₂O:Al₂O₃:P₂O₅:SiO₂:R:C:S＝20～100:1:0.5～2:0.1～1:0.5～2:0.01～1:0～1；

e) Performing secondary crystallization;

f) and e) after the step e) is finished, removing mother liquor from the crystallized product, washing, drying and roasting to obtain the SAPO-11 molecular sieve.

Further, the aluminum source in the step a) is one of pseudo-boehmite, aluminum isopropoxide or aluminum hydroxide; the phosphorus source is phosphoric acid solution; the silicon source is one of tetraethyl orthosilicate (TEOS), silica gel, silica sol or white carbon black.

Furthermore, the reaction kettle in the step b) is a high-pressure reaction kettle with a stirring function, the primary crystallization condition is that the temperature is 60-165 ℃, and the stirring crystallization is carried out for 1-24 hours.

Further, in step c), the template agent is di-n-propylamine, diisopropylamine or a mixture of the di-n-propylamine and the diisopropylamine; the surfactant is cetyl trimethyl ammonium bromide or n-hexadecylamine; the auxiliary agent is oil-water amphiphilic organic matter.

Furthermore, the oil-water amphiphilic organic matter is one of ethanol, butanol, isopropanol, diethyl ether or acetone.

Furthermore, the initial temperature of the mixed liquid pumped into the reaction kettle in the step d) is 40 ℃ or more lower than the temperature of homogeneous gel in the reaction kettle.

Furthermore, the secondary crystallization in the step e) is carried out at the temperature of 170-200 ℃ for 12-24 hours by stirring.

The invention is characterized in that water, template agent, surfactant and auxiliary agent are mixed in a sealed pressure container, and then added into high-temperature phosphorus, aluminum and silicon homogeneous gel. The template agent mixed solution is added at high temperature, so that the system can be kept from a viscous state, gel blocks are prevented from being formed, and the effects of the template agent and the surfactant can be favorably exerted. And the high-temperature phosphorus, aluminum and silicon homogeneous gel meets the low-temperature template agent mixed solution, so that a mesoporous structure is formed.

The invention is characterized in that the obtained SAPO-11 molecular sieve has a mesoporous structure, and the product also has the characteristics of high crystallinity and high specific surface area. Meanwhile, the technical scheme also has the characteristics of high utilization rate of raw materials and high synthesis speed.

The mesoporous SAPO-11 molecular sieve product prepared by the method can be used as an active component of a hydroisomerization catalyst and can also be used as an active component of a catalyst for preparing olefin from methanol.

Drawings

FIG. 1 is an X-ray diffraction spectrum of samples in examples 1 to 6, wherein six samples are SAPO-11 samples with AEL topological structures.

Fig. 2 is a nitrogen adsorption-desorption curve of the sample in example 1, wherein a hysteresis loop is evident on the curve, which indicates that the sample has a mesoporous structure.

Detailed Description

The present invention will be further illustrated with reference to the following examples, but the present invention is not limited to the following examples.

Example 1:

a method for rapidly synthesizing a mesoporous SAPO-11 molecular sieve sequentially disperses pseudo-boehmite, a phosphoric acid solution and alkaline silica sol in deionized water, and rapidly stirs the mixture to prepare homogeneous gel, wherein the mass ratio of each component in the homogeneous gel is as follows: h₂O:Al₂O₃:P₂O₅:SiO₂40:1:0.95: 0.3. And (3) putting the homogeneous gel into a reaction kettle, and stirring and crystallizing for 8 hours at the temperature of 95 ℃.

Diisopropylamine (R), hexadecyl trimethyl ammonium bromide (C) and isopropanol (S) are prepared into mixed liquid in water, and the mixed liquid is stored in a sealed pressure container and kept at a constant temperature of 40 ℃. The mass ratio of each component in the mixed solution is as follows: h₂O:R:C:S＝5:1:0.08:0.02；

Adding the mixed solution into a reaction kettle used for homogeneous gel by a high-pressure pump, wherein the mass ratio of each component in the kettle is as follows H₂O:Al₂O₃:P₂O₅:SiO₂R, C, S, 45:1:0.95:0.3:1:0.08: 0.02. After the completion of the addition, the temperature is rapidly raised to 190 ℃, and the mixture is stirred and crystallized for 22 hours. After crystallization is finished, mother liquor is removed from the product, and the product is washed, dried and roasted to obtain the SAPO-11 molecular sieve which is marked as S-1.

Example 2:

a method for quickly synthesizing mesoporous SAPO-11 molecular sieve includes sequentially dispersing pseudo-boehmite, phosphoric acid solution and acidic silica sol in deionized waterStirring at a high speed. A homogeneous gel was formulated with the following ratios of amounts of the components: h₂O:Al₂O₃:P₂O₅:SiO₂40:1:1: 0.28. And (3) putting the homogeneous gel into a reaction kettle, and stirring and crystallizing for 6 hours at the temperature of 100 ℃.

Diisopropylamine (R) and hexadecyl trimethyl ammonium bromide (C) are prepared into mixed liquid in water, and the mixed liquid is stored in a sealed pressure container and kept at the constant temperature of 55 ℃. The mass ratio of each component in the mixed solution is as follows: h₂O:R:C＝5:1:0.08；

Adding the mixed solution into a reaction kettle used for homogeneous gel by using a high-pressure pump, wherein the mass ratio of each component in the kettle is as follows: h₂O:Al₂O₃:P₂O₅:SiO₂R is 45:1:1:0.28:1: 0.08. After the completion of the supplement, the temperature is rapidly raised to 200 ℃, and the mixture is stirred and crystallized for 15 hours. After crystallization is finished, mother liquor is removed from the product, and the product is washed, dried and roasted to obtain the SAPO-11 molecular sieve which is marked as S-2.

Example 3:

a method for quickly synthesizing mesoporous SAPO-11 molecular sieve comprises the steps of sequentially dispersing pseudo-boehmite, phosphoric acid solution and acidic silica sol in deionized water, and quickly stirring. A homogeneous gel was formulated with the following ratios of amounts of the components: h₂O:Al₂O₃:P₂O₅:SiO₂40:1:1: 0.3. And (3) putting the homogeneous gel into a reaction kettle, and stirring and crystallizing for 4 hours at 125 ℃.

Di-n-propylamine (R), n-hexadecylamine (C) and ethanol (S) are prepared into mixed liquid in water, and the mixed liquid is stored in a sealed pressure container and is kept at the constant temperature of 80 ℃. The mass ratio of each component in the mixed solution is as follows: h₂O:R:C:S＝5:1:0.1:0.04；

Adding the mixed solution into a reaction kettle used for homogeneous gel by using a high-pressure pump, wherein the mass ratio of each component in the kettle is as follows: h₂O:Al₂O₃:P₂O₅:SiO₂R, C, S, 45:1:1:0.3:1:0.1: 0.04. After the completion of the addition, the temperature is rapidly raised to 190 ℃, and the mixture is stirred and crystallized for 20 hours. After the crystallization is finished, the product is subjected toMother liquor is removed, washed, dried and roasted to obtain the SAPO-11 molecular sieve which is marked as S-3.

Example 4:

a method for quickly synthesizing mesoporous SAPO-11 molecular sieve comprises the steps of sequentially dispersing pseudo-boehmite, phosphoric acid solution and alkaline silica sol in deionized water, and quickly stirring. A homogeneous gel was formulated with the following ratios of amounts of the components: h₂O:Al₂O₃:P₂O₅:SiO₂40:1:1: 0.3. And (3) putting the homogeneous gel into a reaction kettle, and stirring and crystallizing for 4 hours at 125 ℃.

Di-n-propylamine (R), n-hexadecylamine (C) and ethanol (S) are prepared into mixed liquid in water, and the mixed liquid is stored in a sealed pressure container and is kept at the constant temperature of 80 ℃. The mass ratio of each component in the mixed solution is as follows: h₂O:R:C:S＝5:1:0.1:0.05；

Adding the mixed solution into a reaction kettle used for homogeneous gel by using a high-pressure pump, wherein the mass ratio of each component in the kettle is as follows: h₂O:Al₂O₃:P₂O₅:SiO₂R, C, S, 45:1:1:0.3:1:0.1: 0.05. After the completion of the addition, the temperature is rapidly raised to 190 ℃, and the mixture is stirred and crystallized for 20 hours. After crystallization is finished, mother liquor is removed from the product, and the product is washed, dried and roasted to obtain the SAPO-11 molecular sieve which is marked as S-4.

Example 5:

a method for quickly synthesizing mesoporous SAPO-11 molecular sieve comprises the steps of sequentially dispersing pseudo-boehmite, phosphoric acid solution and acidic silica sol in deionized water, and quickly stirring. A homogeneous gel was formulated with the following ratios of amounts of the components: h₂O:Al₂O₃:P₂O₅:SiO₂40:1:1: 0.3. And (3) putting the homogeneous gel into a reaction kettle, and stirring and crystallizing for 2 hours at 145 ℃.

Di-n-propylamine (R), n-hexadecylamine (C) and isopropanol (S) are prepared into mixed liquid in water, and the mixed liquid is stored in a sealed pressure container and kept at the constant temperature of 95 ℃. The mass ratio of each component in the mixed solution is as follows: h₂O:R:C:S＝5:1:0.08:0.03；

Mixing the mixed solutionThe gel is added into a reaction kettle used for homogeneous gel by a high-pressure pump, and the mass ratio of each component in the kettle is as follows: h₂O:Al₂O₃:P₂O₅:SiO₂R, C, S, 45:1:1:0.3:1:0.08: 0.03. After the completion of the addition, the temperature is rapidly raised to 200 ℃, and the mixture is stirred and crystallized for 16 hours. After crystallization is finished, mother liquor is removed from the product, and the product is washed, dried and roasted to obtain the SAPO-11 molecular sieve which is marked as S-5.

Example 6:

a method for quickly synthesizing mesoporous SAPO-11 molecular sieve comprises the steps of sequentially dispersing pseudo-boehmite, phosphoric acid solution and acidic silica sol in deionized water, and quickly stirring. A homogeneous gel was formulated with the following ratios of amounts of the components: h₂O:Al₂O₃:P₂O₅:SiO₂40:1:1: 0.3. And (3) putting the homogeneous gel into a reaction kettle, and stirring and crystallizing for 10 hours at the temperature of 80 ℃.

Di-n-propylamine (R), cetyl trimethyl ammonium bromide (C) and ethanol (S) are prepared into mixed liquid in water, and the mixed liquid is stored in a sealed pressure container and is kept at the constant temperature of 30 ℃. The mass ratio of each component in the mixed solution is as follows: h₂O:R:C:S＝5:1:0.1:0.01；

Adding the mixed solution into a reaction kettle used for homogeneous gel by using a high-pressure pump, wherein the mass ratio of each component in the kettle is as follows: h₂O:Al₂O₃:P₂O₅:SiO₂R, C, S, 45:1:1:0.3:1:0.1: 0.01. After the completion of the supplement, the temperature is rapidly raised to 200 ℃, and the mixture is stirred and crystallized for 12 hours. After crystallization is finished, mother liquor is removed from the product, and the product is washed, dried and roasted to obtain the SAPO-11 molecular sieve which is marked as S-6.

Comparative example:

sequentially dispersing pseudo-boehmite, a phosphoric acid solution, di-n-propylamine (DPA) and acidic silica sol in deionized water, and rapidly stirring to prepare homogeneous gel, wherein the mass ratio of each component in the homogeneous gel is as follows: h₂O:Al₂O₃:P₂O₅:DPA:SiO₂40:1:1:1: 0.3. The homogeneous gel was charged into a reaction vessel, stirred at 180 ℃ and held at constant temperature for 48 hours. Constant temperature knotAnd after finishing, removing mother liquor from the product, washing, drying and roasting to obtain the SAPO-11 molecular sieve of the comparative example.

Test example:

referring to the following table, the physical properties of the samples of examples 1-6 and comparative examples are shown. It can be found that the example samples are characterized by a high specific surface area (especially its outer specific surface area) and a large pore volume, compared to the comparative examples.