Preparation method for mordenite with high Si/Al ratio and small crystal particle

A technology of mordenite and high silicon-aluminum ratio, which is applied in the direction of crystalline aluminosilicate zeolite, mercerized crystalline aluminosilicate zeolite, nanotechnology, etc., can solve the problem of large synthetic particle size, etc., and achieve reduced synthesis cost and excellent catalytic performance , the effect of good application prospects

Active Publication Date: 2012-07-25
EAST CHINA NORMAL UNIV
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  • Application Information

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Problems solved by technology

Chinese patent CN 1050011A reports the synthesis method of using cheap water glass as the silicon source mordenite as the seed crystal to prepare high silicon-aluminum ratio mordenite. The highest silicon-aluminum ratio can reach 25, but the synthetic particle size is larger than 1.0 μm
The results of literature and Chinese patent surveys show that the synthesis of low-cost and environmentally friendly high-silicon-aluminum-ratio small-grain mordenite has not been reported yet.

Method used

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  • Preparation method for mordenite with high Si/Al ratio and small crystal particle
  • Preparation method for mordenite with high Si/Al ratio and small crystal particle
  • Preparation method for mordenite with high Si/Al ratio and small crystal particle

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Embodiment 1

[0024] Add 9.50 g of NaOH to 190 ml of deionized water, stir until a clear solution, add 4.8 g of sodium metaaluminate to the above solution, and continue stirring at room temperature until all the solids are dissolved. Add 29.1 g of fuming silica gel to the above mixed solution, continue strong magnetic stirring for 1 hour, then add 1.7 g of layered FER zeolite molecular sieves into the reaction system as a seed crystal, continue stirring for 0.5 hours after the addition, and finally put the mixture into Put it into a polytetrafluoroethylene-lined stainless steel crystallization kettle, seal it and crystallize in an oven at 170°C for 24 hours, and obtain a solid product after conventional suction filtration, washing, and drying; the molar composition of the initial sol of the mixture is: SiO 2 :Al 2 o 3 =20, Na 2 O: SiO 2 =0.25,H 2 O: SiO 2 =45.

[0025]The solid product is analyzed as mordenite by X-ray, and its SiO 2 :Al 2 o 3 The molar ratio is 15.0, and the fin...

Embodiment 2

[0027] Except that decasil layered silicate (Octosilicate) was used instead of layered FER zeolite molecular sieve in Example 1 as the seed crystal, other preparation conditions were the same as in Example 1.

[0028] The solid product is analyzed as mordenite by X-ray, and its SiO 2 :Al 2 o 3 The molar ratio is 13.5, and the final 1 μm spherical particles are composed of spherical nanocrystals with particle sizes ranging from 50 to 100 nm. The results of X-ray diffraction and SEM characterization are as follows: figure 1 b and figure 2 c / d.

Embodiment 3

[0030] Except that the layered mesoporous molecular sieve MCM-50 was used as the seed crystal instead of the layered FER zeolite molecular sieve in Example 1, other preparation conditions were the same as in Example 1.

[0031] The solid product is analyzed as mordenite by X-ray, and its SiO 2 :Al 2 o 3 The molar ratio is 11.0, and the final 5 μm spherical particles are composed of needle-like nanocrystals with particle sizes ranging from 300 to 600 nm. The results of X-ray diffraction and SEM characterization are as follows: figure 1 c and figure 2 e / f.

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Abstract

The invention discloses a preparation method for mordenite with a high Si / Al ratio and a small crystal particle, which comprises the following steps of: firstly, dissolving an Al source in sodium oxide solution; after an Si source is added, stirring and dispersing for certain time at room temperature and under strong magnetic force; mixing the Al source solution and the Si source solution which are evenly dispersed into glue at the room temperature; adding inorganic lamellar precursors, such as lamellar zeolite molecular sieves, lamellar silicate and the like to serve as seed crystal; after mixture is stirred and mixed evenly at the room temperature and under the strong magnetic force, transferring into a reaction crystallization kettle; at the temperature of 150-170DEG C, carrying out crystallization reaction for 0.5-3 days; and obtaining a solid product after common suction filtration, washing and drying. The synthesis method disclosed by the invention has the characteristics that expensive organic amine template is not used as structure-directing agent, and instead, the easily-obtained inorganic lamellar precursors with abundant source and low price are used as the seed crystal to directly synthesize a mordenite molecular sieve with the high Si / Al ratio. The prepared nanometer mordenite molecular sieve has the advantages of high degree of crystallinity and purity, controllable particle size and morphology, low cost and small environment pollution, and is convenient for industrially producing on a large scale.

Description

technical field [0001] The invention relates to the synthesis of zeolite molecular sieves, in particular to a synthesis method of nanometer mordenite molecular sieves with high silicon-aluminum ratio. Specifically, it is a method for synthesizing nano-mordenite molecular sieves with high silicon-aluminum ratio by adding nonpolar layered precursors as nucleation accelerators and adjusting synthesis conditions without using organic ammonium as a structure-directing agent. Background technique [0002] Microporous molecular sieves have uniform pore structure, suitable acidity and good hydrothermal stability, and have become important petrochemical catalytic materials. Hydrogen-type mordenite with one-dimensional twelve-membered ring straight cylindrical channels (pore size 0.695 nm × 0.581 nm) exhibits excellent catalytic performance in toluene disproportionation, alkylation, isomerization of C8 aromatics and selective disproportionation of toluene . However, the mordenite mo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/26B82Y40/00
Inventor 张坤袁恩辉蒋金刚徐浪浪罗琛吴鹏
Owner EAST CHINA NORMAL UNIV
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