Method for preparing MFI catalyst carrying transition elements and MFI catalyst application

A transition element and catalyst technology, applied in the preparation of nano-layered MFI catalysts, can solve the problems of large diffusion resistance and low catalytic activity, and achieve the effects of small internal diffusion resistance, improved catalytic activity, and short pores

Inactive Publication Date: 2012-03-21
TAIYUAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the MFI in this catalyst is prepared by a traditional method, which has a large diffusion resistance and low catalytic activity in the low temperature range.

Method used

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  • Method for preparing MFI catalyst carrying transition elements and MFI catalyst application
  • Method for preparing MFI catalyst carrying transition elements and MFI catalyst application
  • Method for preparing MFI catalyst carrying transition elements and MFI catalyst application

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Experimental program
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specific Embodiment approach 1

[0033] The object of the present invention is to provide a kind of preparation method of loading transition element MFI catalyst and the application of MFI catalyst thereof, the key of this catalyst synthesis is to develop synthetic gemini cationic surfactant---dibromide-1-(dimethyl Hexylammonium)-6-(dimethyloctadecylammonio)hexane:

[0034]

[0035] As a template agent, with adjustable dynamic rotation synthesis technology, after atom condensation, rearrangement, nucleation, and crystallization, the nucleated atoms are aligned in a plane to form a single-cell nano-layered MFI catalyst support material. The catalytic material modified by transition elements can be used for NO x Selective catalytic reduction, especially for low-temperature NH in diesel vehicle exhaust 3 - SCR catalytic reaction.

[0036] The present invention is characterized in that it effectively overcomes the thermodynamically controlled Ostwald ripening effect in the synthesis system, and the MFI molec...

Embodiment 1

[0045] Water glass (an aqueous solution of sodium silicate, SiO 2 / Na=1.75, 29wt% SiO 2 ), Al 2 (SO 4 ) 3 18. h 2 O, NaOH, C 18-6-6 Br 2 , H 2 SO 4 Mixed with distilled water to obtain a composition of 20Na 2 O:Al 2 o 3 : 69SiO 2 : 10C 18 - 6 - 6 Br 2 : 16H 2 SO 4 : 4,000H 2 O's gel. The resulting gel was transferred to a polytetrafluoroethylene-coated stainless steel autoclave and heated at 150-160°C for 120 hours. The autoclave speed was set at 60-120 r.p.m. After crystallization, the product was filtered. Wash with distilled water and dry at 110-130°C. The product is calcined under flowing air at 450-650°C for 4-6 hours to obtain a single cell nano-layer MFI catalytic material with mesopore and micropore scale thickness of only 2-5 nanometers.

Embodiment 2

[0047] Water glass, Al 2 (SO 4 ) 3 18. h 2 O, NaOH, C 18-6-6 Br 2 , H 2 SO 4 Mixing with distilled water gives a composition of 25Na 2 O:Al 2 o 3 : 80SiO 2 : 10C 18 - 6 - 6 Br 2 :36H 2 SO 4 : 4,000H 2 O's gel. The resulting gel was transferred to a Teflon-coated stainless steel autoclave and heated at 150-160°C for five days with the autoclave speed set at 60-120 r.p.m. After crystallization, the product was filtered and Wash with distilled water and dry at 110-130°C. Calcining the product under flowing air at 450-650°C for 4-6 hours can also obtain a single-cell nano-layer MFI catalytic material with a mesopore and micropore scale and a thickness of only 2-5 nanometers.

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Abstract

Disclosed are a method for preparing an MFI catalyst carrying transition elements and MFI catalyst application. Cationic gemini surfactant- dibromide-1-(dimethyl hexyl ammonium)-6-(dimethyl octodecyl ammonium) hexane is used as structure directing agent of the MFI catalyst, sodium silicate is used as a silicon source and is subjected to low-temperature hot crystallization under self-generated pressure in a rotationally dynamic manner, and after directional polycondensation, rearrangement, nucleation and growth of inorganic atom Si-Al-Na-O on a two-dimensional plane, and single-structure-cell nano-layer MFI catalytic materials which are in mesoporous and microporous structure with the thickness ranging from 2 nanometers to 5 nanometers only are synthetized. Activity center point number of the MFI catalyst is increased evidently by utilizing two-dimensional single-structure-cell nano MFI carrying transition elements of Fe and Mo, the thickness of the catalyst crystal is reduced effectively, diffusion path is shortened, and molecular diffusion is speeded up. In addition, according to the result of a test of utilizing the selective catalytic reduction (SCR) process to remove tail gas of automobiles, NOx removal rate reaches 99.5%.

Description

technical field [0001] The invention relates to a preparation method of a nano-layered MFI catalyst, that is, to synthesize a single unit cell nano-layer MFI molecular sieve catalyst carrier material with a thickness of 2 to 5 nm, which is used for selective catalytic reduction of NOx after being modified with transition elements, N 2 Catalyst for the decomposition of O and the reaction of phenoxidation to phenol. technical background [0002] MFI molecular sieve has a three-dimensional pore structure, strong surface acidity and orderly micropore structure, as well as adjustable size and shape. It is widely used as catalyst carrier material in the synthesis reaction of petrochemicals and fine chemicals. . In recent years, the synthesis technology of nano-sized molecular sieves has developed rapidly. Nano-sized molecular sieves loaded with active components can increase the specific surface area and intracrystalline diffusion rate of catalysts, enhance the conversion capaci...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J29/40B01J29/46B01J29/48B01J35/02B82Y40/00B01D53/56B01D53/94
Inventor 李哲何凯侯淑滨李振
Owner TAIYUAN UNIV OF TECH
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