Modified ZSM-5 molecular sieve as well as modifying method and application thereof

A ZSM-5, molecular sieve technology, applied in the field of molecular sieves, can solve the problems of unsatisfactory and unsatisfactory catalytic life and selectivity, and achieve the effects of reducing diffusion resistance, prolonging life and increasing selectivity

Inactive Publication Date: 2014-06-11
TAIYUAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In patent CN1530322A, the ZSM-5 structure zeolite with larger crystal grains is treated with lye, and the maximum mesopore specific surface area is 165m 2 / g, but still cannot meet the requirements of ZSM-5 molecular sieve with high mesoporous content in gasoline synthesis
[0004] Patent CN102464336A describes that in a closed system containing low-molecular-weight organic solvents, ZSM-5 zeolite is first treated with alkali solution, then treated with acid solution, and finally modified by separation, washing and drying. ZSM-5 zeolite, its mesopore specific surface area is up to 300m 2 / g, the most probable pore size is 3.5nm, but the pore size after treatment still limits the diffusion of hydrocarbon molecules in the gasoline boiling range, and the catalytic life and selectivity are not very ideal

Method used

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  • Modified ZSM-5 molecular sieve as well as modifying method and application thereof
  • Modified ZSM-5 molecular sieve as well as modifying method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 5

[0038] The molecular sieve used in Example 5 and Comparative Example 1 is the commercial ZSM-5 molecular sieve purchased by Nankai Catalyst Factory. The silicon-aluminum ratio is 20, and the particle size is 10 μm. The most probable pore diameter of the molecular sieve measured by nitrogen adsorption and desorption is 0.1 nm, and the specific surface area 30m 2 / g.

[0039] The molecular sieve used in comparative examples 2 and 3 is the commercial ZSM-5 molecular sieve purchased by Nankai Catalyst Factory. The silicon-aluminum ratio is 100, the particle size is 5 μm, and the most probable pore diameter of the molecular sieve measured by nitrogen adsorption and desorption is 1.0 nm, and the specific surface area is 100 m 2 / g.

Embodiment 1

[0041] (1) Take 20g of purchased commercial ZSM-5 molecular sieve and roast at 500°C for 3 hours;

[0042] (2) Add the roasted ZSM-5 molecular sieve into 400ml of hydrochloric acid solution with a concentration of 2mol / L according to the liquid-solid ratio of 20ml / g, and stir in a water bath at 80°C for 4h;

[0043] (3) Centrifuge the mixture obtained in step (2). The centrifuged solid is stirred and washed 3 times with dilute nitric acid with a concentration of 0.5mol / L in a three-necked flask at a washing temperature of 80°C, and then separated and dried. , Roasting. Among them, the separation process uses centrifugal separation familiar in the industry, the drying process is 12 hours at 120°C, and the roasting process is 550°C for 5 hours.

[0044] (4) Add the product obtained in step (3) into a three-necked flask filled with 400ml of NaOH solution with a concentration of 0.4mol / L, and stir at 80°C for 2h;

[0045] (5) Centrifuge the mixture obtained in step (4). The cent...

Embodiment 2

[0048] (1) Take 10g of purchased commercial ZSM-5 molecular sieve and roast at 600°C for 6 hours;

[0049] (2) Add the roasted ZSM-5 molecular sieve into 500ml of hydrochloric acid solution with a concentration of 4mol / L according to the liquid-solid ratio of 50ml / g, and stir in a water bath at 60°C for 6h;

[0050] (3) The mixture obtained in step (2) is centrifuged, and the centrifuged solid is stirred and washed 3 times with dilute nitric acid with a concentration of 3 mol / L in a three-necked flask at a washing temperature of 60°C, and then separated, dried, Roasting, wherein, the separation process uses filtration separation familiar in the industry, the drying process is 8 hours at 150° C., and the calcination process is 6 hours at 400° C.

[0051] (4) Add the product obtained in step (3) into a three-necked flask filled with 500ml of NaOH solution with a concentration of 0.2mol / L, and stir at 60°C for 4h;

[0052] (5) Centrifuge the mixture obtained in step (4). The cen...

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Abstract

A modified ZSM-5 molecular sieve has a most preferable bore diameter of 4nm-12nm, a mesoporous specific surface area of 300m<2> / g-400m<2> / g and a particle diameter of 0.1mu m-10mu m. The modified ZSM-5 molecular sieve disclosed by the invention has the advantages of being long in service life, high in selectivity, rich in bores with the bore parameter of not less than 5 nm, and high in mesoporous specific surface area.

Description

technical field [0001] The invention belongs to a molecular sieve, in particular to a modified ZSM-5 molecular sieve and its modification method and application. Background technique [0002] ZSM-5 molecular sieve is a kind of zeolite molecular sieve with MFI topology and high-silicon five-membered ring type. Its unique intersecting two-dimensional channels not only provide space confinement for shape-selective catalysis, but also provide Rich in and out channels. The special pore structure of ZSM-5 molecular sieve determines that it has good shape-selective catalytic performance, but the pore size of ZSM-5 molecular sieve is only 0.53nm, and its catalytic performance is limited in some reactions containing macromolecules, especially the reaction formation The macromolecules are not easy to diffuse out in its pores, resulting in carbon deposition and deactivation, which seriously affects its catalytic life. Therefore, enlarging the pore size of ZSM-5 molecular sieve and in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/38B01J29/40C10G3/00
CPCY02P30/20
Inventor 李忠孟凡会张洪建邹佩良郑华艳
Owner TAIYUAN UNIV OF TECH
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