Synthesis method of nanometer ZSM-5 molecular sieve

A technology of ZSM-5 and synthesis method, applied in the direction of nanotechnology, nanotechnology, nanotechnology for materials and surface science, etc., can solve the problems of small pore size, affecting lifespan, and difficulty in fully utilizing acidic sites

Active Publication Date: 2017-06-09
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Conventional ZSM-5 crystals are generally micron-sized, due to their small pore size (approximately ), which is not conducive to molecular diffusion and mass transfer, and it is difficult to make full use of the acidic sites in the pores. On the other hand, the catalyst is prone to carbon deposition and deactivation, which affects its life

Method used

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  • Synthesis method of nanometer ZSM-5 molecular sieve
  • Synthesis method of nanometer ZSM-5 molecular sieve
  • Synthesis method of nanometer ZSM-5 molecular sieve

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Embodiment 1: NaOH 0.71g, NaAlO 2 Put 0.58g in a 250ml polypropylene beaker, add 32.5g of deionized water, stir at room temperature for 5 minutes to make NaOH and NaAlO 2 Dissolve, add 29g of polyethyleneimine (50% aqueous solution) with an average molecular weight of 70000 to the above solution, stir for 10 minutes to obtain a uniform solution, slowly add 16g of LUDOX AS-40 silica sol dropwise to the above solution under stirring . The resulting mixture was placed under magnetic stirring at 30°C (600 rpm) for 4h for gelation / precrystallization, and then transferred to a 100ml autoclave with a Teflon liner for crystallization at 150°C for 5 days (operations taken The way is to put the reaction kettle on the rotating motor, the motor speed is 80 rpm). After the crystallization, the reaction kettle was placed in cold water and quickly lowered to room temperature, then filtered with suction, and washed repeatedly with 1L deionized water. The obtained precipitate was drie...

Embodiment 2

[0016] Embodiment 2: NaOH 0.71g, NaAlO 2 Put 0.29g in a 250ml polypropylene beaker, add 47g of deionized water, stir at room temperature for 5 minutes to make NaOH and NaAlO 2 Dissolve, add 14.4g of polyethyleneimine with an average molecular weight of 1800 to the above solution, stir for 10 minutes to obtain a uniform solution, slowly add 16g of LUDOX AS-40 silica sol dropwise into the above solution under stirring. The resulting mixture was placed under magnetic stirring at 30°C (600 rpm) for 4h for gelation / precrystallization, and then transferred to a 100ml autoclave with a Teflon liner for crystallization at 150°C for 5 days (operations taken The way is to put the reaction kettle on the rotating motor, the motor speed is 60 rpm). After the crystallization, the reaction kettle was placed in cold water to quickly cool down to room temperature, then suction filtered and washed repeatedly with 1L of deionized water, and the obtained precipitate was dried at 110°C for 12 hour...

Embodiment 3

[0017] Embodiment 3: The operation is the same as that of Embodiment 2, the amount of materials added remains unchanged, and the crystallization is carried out at 135° C. for 10 days. XRD shows that the obtained sample is ZSM-5 and Y-phase SiO 2 (PDF #31-1233) Mixed Phase.

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Abstract

The invention provides a synthesis method of a nanometer ZSM-5 molecular sieve, and belongs to the technical field of inorganic synthesis and catalyst preparation. The method uses silica sol and sodium metaaluminate as a silicon source and an aluminum source. In the synthesis process, tetrapropylammonium hydroxide and polyethyleneimine can be added in the synthesis process to be used as an organic template agent, or only the polyethyleneimine is added; after the raw material mixing, gelling is performed for 0.5 to 10 hours after the raw material mixing; then, the materials are transferred into a high-pressure reaction kettle to be crystallized at 120 to 180 DEG C; after the obtained ZSM-5 molecular sieve is roasted, the crystal grain dimension is smaller than 50nm. The molecular sieve prepared by the method has the advantages that the crystal grain size is small; the particle diameter is uniform; the operation is simple; the amplified production is easy, and the like.

Description

technical field [0001] The invention belongs to the technical field of inorganic synthesis and catalyst preparation, and relates to a synthesis method of nanometer molecular sieves, in particular to a preparation method of nanometer ZSM-5 molecular sieves. Background technique [0002] Mobil Corporation firstly reported in 1972 the method for synthesizing ZSM-5 molecular sieves using quaternary ammonium salts as a template (USP3702886). ZSM-5 is a molecular sieve with a high silicon-aluminum ratio of MFI structure. There is no cage in its structure, but a 3-dimensional intersecting pore structure, so it exhibits unique selective catalytic performance. At the same time, ZSM-5 has strong acidity and With excellent hydrothermal stability, it is widely used in catalytic cracking, synthesis of p-xylene, conversion of methanol to olefins and gasoline. Conventional ZSM-5 crystals are generally micron-sized, due to their small pore size (approximately ), which is not conducive to...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/40B82Y30/00
CPCB82Y30/00C01B39/40C01P2002/72C01P2004/03
Inventor 展恩胜申文杰李勇
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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