阅读说明：本技术 一种微孔分子筛表面附晶生长介孔分子筛的方法 (Method for growing mesoporous molecular sieve by attaching crystals on surface of microporous molecular sieve ) 是由 黄新毫 于 2020-05-22 设计创作，主要内容包括：本发明涉及无机材料和催化技术领域,且公开了一种微孔分子筛表面附晶生长介孔分子筛的方法,所述微孔分子筛为ZSM-5、ZSM-35、HZSM-5以及Y分子筛中的一种。所述活性溶液为模板剂、二氧化硅、三氧化二铝、氧化钠和水制得的组合化合物,且活性溶液内各种原料摩尔比为1～2：0.05～0.1:0.15～0.25：0.15：60～100。通过在KBr将离子引入到微孔分子筛的内部,将微孔分子筛表面的电场性能发生改变,以利于离子交换,进而改变了电荷分布,使得微孔分子筛与模板剂、二氧化硅、三氧化二铝以及氧化钠制得的组合化合物进行发生离子交换,经过孔壁结晶后,从而附晶生长制备出介孔分子筛,整体与传统的附晶生长相比,具有明显的催化活性,结晶度较高。(The invention relates to the technical field of inorganic materials and catalysis, and discloses a method for growing a mesoporous molecular sieve by epimorphic growth on the surface of a microporous molecular sieve, wherein the microporous molecular sieve is one of ZSM-5, ZSM-35, HZSM-5 and Y molecular sieves. The active solution is a combined compound prepared from a template agent, silicon dioxide, aluminum oxide, sodium oxide and water, and the molar ratio of various raw materials in the active solution is 1-2: 0.05-0.1: 0.15-0.25: 0.15: 60 to 100. The method is characterized in that ions are introduced into the microporous molecular sieve by KBr, the electric field performance on the surface of the microporous molecular sieve is changed, so that ion exchange is facilitated, and further, the charge distribution is changed, so that the microporous molecular sieve is subjected to ion exchange with a composite compound prepared from a template agent, silicon dioxide, aluminum oxide and sodium oxide, and after pore wall crystallization, the mesoporous molecular sieve is prepared by epicrystal growth.)

1. A method for growing a mesoporous molecular sieve by attaching crystals on the surface of a microporous molecular sieve comprises the following steps:

s1, grinding KBr and microporous molecular sieve raw powder into a standard sieve with the aperture of 0.05mm, and then violently stirring the standard sieve with a hexadecyl trimethyl ammonium chloride solution at the temperature of 30-50 ℃ for 25-30 hours to form a prepared suspension;

s2, sequentially dissolving an aluminum source, an alkali source and a silicon source in deionized water, and uniformly stirring until the mixture is white, thereby forming precursor sol of the mesoporous molecular sieve;

s3, dripping the sol of S2 into the prepared suspension of S1, adding an active solution, continuously stirring for 15 minutes, and adding 50% acetic acid to adjust the pH value to be 8-10;

s4, putting the material S3 into a crystallization kettle containing polytetrafluoroethylene, adjusting the temperature to 110-120 ℃ for crystallization for 1-3 hours, crystallizing under the hydrothermal condition of autogenous pressure and crystallization temperature, filtering, washing and drying the obtained crystallization liquid, drying at 100 ℃ for 24-48 hours, and calcining at the rate of 2-3 ℃ in air atmosphere for 8 hours to obtain the product.

2. The method of claim 1, wherein the mesoporous molecular sieve is grown on the surface of the microporous molecular sieve by epicrystal growth, and the method comprises the following steps: the microporous molecular sieve is one of ZSM-5, ZSM-35, HZSM-5 and Y molecular sieves.

3. The method of claim 1, wherein the mesoporous molecular sieve is grown on the surface of the microporous molecular sieve by epicrystal growth, and the method comprises the following steps: the aluminum source is one of aluminum sulfate, aluminum nitrate or aluminum hydroxide, the silicon source is one of silica gel, white carbon black and monodisperse silicon dioxide, and the alkali source is lithium hydroxide.

4. The method of claim 1, wherein the mesoporous molecular sieve is grown on the surface of the microporous molecular sieve by epicrystal growth, and the method comprises the following steps: the active solution is a combined compound prepared from a template agent, silicon dioxide, aluminum oxide, sodium oxide and water, and the molar ratio of various raw materials in the active solution is 1-2: 0.05-0.1: 0.15-0.25: 0.15: 60 to 100.

5. The method of claim 1, wherein the mesoporous molecular sieve is grown on the surface of the microporous molecular sieve by epicrystal growth, and the method comprises the following steps: the template agent is C6H13 (CH)₃)₃NBR、C8-18N+(CH₃)₃、C16N+(CH₃)₃And C10-16N + CH₃(CH₂CH₃)₂One or more of (a).

Technical Field

The invention relates to the technical field of inorganic materials and catalysis, in particular to a method for growing a mesoporous molecular sieve by attaching crystals on the surface of a microporous molecular sieve.

Background

The microporous molecular sieve has the properties of large surface area, high hydrothermal stability, rich and uniform micropores, adjustable surface properties and the like, is widely used as a catalyst and has been widely applied to petrochemical industry, molecular sieves are often applied to synthesis of petrochemical industry and organic intermediates and separation of substances as the catalyst, the mesoporous molecular sieve with crystal attachment growth on the surface of the microporous molecular sieve is crystal attachment growth on the surface of zeolite by methods such as an ion exchange method and the like to obtain an expected pore diameter, and the mesoporous molecular sieve and the microporous molecular sieve are compounded to obtain a composite molecular sieve with better performance, so that the material is expected to have wide application prospects in the aspects of adsorption and catalysis of macromolecules.

The prior method for producing the mesoporous molecular sieve by the epicrystals has low catalytic capability and selectivity, and the product obtained by combining the microporous molecular sieve and the mesoporous molecular sieve has the advantages that under the same reaction condition, mesopores are not easy to form, the crystallization degree of the products is poor, and the catalytic activity and the selectivity can not meet the requirements, so the method for growing the mesoporous molecular sieve by the epicrystals on the surface of the microporous molecular sieve is provided.

Disclosure of Invention

In order to solve the above technical problems, the present invention provides an inorganic material and a catalyst x, which are achieved by the following specific technical means:

a method for growing a mesoporous molecular sieve by attaching crystals on the surface of a microporous molecular sieve comprises the following steps:

s1, grinding KBr and microporous molecular sieve raw powder into a standard sieve with the aperture of 0.05mm, and then violently stirring the standard sieve with a hexadecyl trimethyl ammonium chloride solution at the temperature of 30-50 ℃ for 25-30 hours to form a prepared suspension;

s2, sequentially dissolving an aluminum source, an alkali source and a silicon source in deionized water, and uniformly stirring until the mixture is white, thereby forming precursor sol of the mesoporous molecular sieve;

s3, dripping the sol of S2 into the prepared suspension of S1, adding an active solution, continuously stirring for 15 minutes, and adding 50% acetic acid to adjust the pH value to be 8-10;

s4, putting the material S3 into a crystallization kettle containing polytetrafluoroethylene, adjusting the temperature to 110-120 ℃ for crystallization for 1-3 hours, crystallizing under the hydrothermal condition of autogenous pressure and crystallization temperature, filtering, washing and drying the obtained crystallization liquid, drying at 100 ℃ for 24-48 hours, and calcining at the rate of 2-3 ℃ in air atmosphere for 8 hours to obtain the product.

Preferably, the microporous molecular sieve is one of ZSM-5, ZSM-35, HZSM-5 and Y molecular sieves.

Preferably, the aluminum source is one of aluminum sulfate, aluminum nitrate or aluminum hydroxide, the silicon source is one of silica gel, white carbon black and monodisperse silica, and the alkali source is lithium hydroxide.

Preferably, the active solution is a combined compound prepared from a template agent, silicon dioxide, aluminum oxide, sodium oxide and water, and the molar ratio of various raw materials in the active solution is 1-2: 0.05-0.1: 0.15-0.25: 0.15: 60 to 100.

Preferably, the template agent is C6H13 (CH)₃)₃NBR、C8-18N+(CH₃)₃、C16N+(CH₃)₃And C10-16N + CH₃(CH₂CH₃)₂One or more of (a).

Advantageous effects

Compared with the prior art, the invention provides a method for growing a mesoporous molecular sieve by attaching crystals on the surface of a microporous molecular sieve, which has the following beneficial effects:

according to the method for growing the mesoporous molecular sieve by epimorphic growth on the surface of the microporous molecular sieve, ions are introduced into the microporous molecular sieve by KBr, the electric field performance on the surface of the microporous molecular sieve is changed, so that ion exchange is facilitated, the charge distribution is changed, the microporous molecular sieve is subjected to ion exchange with a combined compound prepared from a template agent, silicon dioxide, aluminum oxide and sodium oxide, and after pore wall crystallization, the mesoporous molecular sieve is prepared by epimorphic growth.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention is further described below by way of examples: