Zsm-11/silicalite-2 core-shell molecular sieve with dense shell and preparation method thereof

A ZSM-11, core-shell molecular sieve technology, applied in molecular sieve catalysts, molecular sieve characteristic polymorphic crystalline silicon, chemical instruments and methods, etc., can solve the problems of complex shell structure modulation and unsatisfactory control effects, and achieve simplification control effect

Active Publication Date: 2018-09-14
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is that the corresponding matching relationship between the synthesis method and catalytic performance of the core-shell molecular sieve and the synthesis parameters (such as shell ratio, compactness and uniformity) of the prepared catalyst shell structure solves the problem of existing synthetic technology. There are practical problems such as complex modulation of the shell structure and unsatisfactory regulation effect.

Method used

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  • Zsm-11/silicalite-2 core-shell molecular sieve with dense shell and preparation method thereof
  • Zsm-11/silicalite-2 core-shell molecular sieve with dense shell and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] 320 grams of ZSM-11 (dried and unroasted, molar silicon-aluminum ratio of 100) raw powder is used as a nuclear phase molecular sieve, added to 0.05 mol / liter urea aqueous solution, and the temperature is raised to 80 under stirring o C and kept for 2 hours, filtered and heated at 120 o C drying in an air atmosphere to obtain the ZSM-11 nuclear phase molecular sieve after the outer surface treatment.

[0022] 120 grams of white carbon black, 10 grams of phenyltrimethylammonium chloride (BTMACl), 800 grams of tetrabutylammonium hydroxide and 6000 milliliters of water were evenly stirred to form a gel to obtain the silicalite-2 shell crystallization mother liquor, and slowly added while stirring The ZSM-11 nuclear phase molecular sieve powder after the above-mentioned weak base passivation treatment was stirred and aged for 2 hours and then 500 grams of glycerin was added. 160 o The molecular sieve sample obtained by static crystallization in oven C for 30 hours, filtere...

Embodiment 2

[0024] 40 grams of ZSM-11 (dried and unroasted, molar silicon-aluminum ratio of 40) raw powder is used as a nuclear phase molecular sieve, added to 0.05 mol / liter HMT aqueous solution, and the temperature is raised to 90 under stirring o C and kept for 3 hours, filtered and heated at 120 o C drying in an air atmosphere to obtain the ZSM-11 nuclear phase molecular sieve after the outer surface treatment.

[0025] 35 grams of TEOS, 6 grams of TBABr, and 180 milliliters of water were evenly stirred to form a gel to obtain the silicalite-2 shell crystallization mother liquor, and the ZSM-11 nuclear phase molecular sieve powder after the above treatment was slowly added while stirring, and then added after stirring and aging for 1 hour 10 grams of ethanol, the mixed system was quickly moved into the polytetrafluoroethylene-lined stainless steel coat crystallization kettle, placed in 180 o The molecular sieve sample obtained by static crystallization in oven C for 24 hours was take...

Embodiment 3～15

[0027] Examples 3-15 are ZSM-11 / silicalite-2 core-shell molecular sieves ES3-15 synthesized according to the similar conditions and method steps of Example 1 with the raw material ratio and synthetic materials in Table 1, see Table 1 for details.

[0028] Table 1

[0029]

[0030] Table 1 (continued)

[0031]

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Abstract

The invention relates to a compact shell ZSM-11 / Silicalite-2 core-shell molecular sieve and a preparation method thereof. Mainly for modification of adsorption activity sites without shape selective performance on a ZSM-11 silicon-aluminum molecular sieve outer surface, under the premise of effective use of shell raw materials and templates, a layer of compact and high strength Silicalite-2 shell uniformly grows on the outer surface of a ZSM-11 crystal grain. According to the invention, pretreatment is carried out on a weak alkali aqueous solution of a core phase zeolite material, then in a core-shell molecular sieve crystallization system and under appropriate reaction conditions, the core-shell molecular sieve containing a compact shell can be obtained, can be effectively used for shape selective adsorption separation of xylene isomers, also can be used for aromatic hydrocarbon shape-selective disproportionation and shape-selective alkylation reaction so as to generate a lot of useful p-xylene isomers. Through blending of the core and the shell, the catalyst has the characteristics of strong adsorption activity, high catalytic activity, large aromatic hydrocarbon treatment amount, high integrated mechanical strength, low application loss, and high p-xylene product selectivity, and can be used in industrial production.

Description

technical field [0001] The invention relates to a ZSM-11 / Silicalite-2 core-shell molecular sieve and a preparation method thereof. Background technique [0002] Xylene is mainly produced through simple disproportionation of toluene or transalkylation of aromatic hydrocarbons. In recent years, due to the development of plastics, synthetic fibers and synthetic rubber industries, the demand for p-xylene has increased rapidly, so the production process route of xylene has been favored by people. widespread attention. Molecular sieves are widely used in petroleum refining and processing, and play a pivotal role in petrochemical industries such as catalytic reforming, catalytic cracking, aromatic hydrocarbon alkylation, isomerization, and toluene disproportionation. Zeolite molecular sieves can be divided into small-pore, medium-pore and large double-pore zeolites according to their pore or channel system. Pentasil medium-pore zeolite belongs to ten-membered ring system, and the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J29/40C01B39/38C01B37/02
Inventor 童伟益孔德金
Owner CHINA PETROLEUM & CHEM CORP
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