Method for preparing rare earth-containing MCM-49 molecular sieve

A MCM-49, molecular sieve technology, applied in molecular sieve compounds, chemical instruments and methods, inorganic chemistry, etc., can solve the problems of difficult exchange, large radius of hydrated ions, unsatisfactory exchange product uniformity, etc. Stability, the effect of reducing the cost of synthesis

Inactive Publication Date: 2009-07-01
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Generally by the traditional ion exchange method, the Re 3+ Ions are exchanged into the pores of molecular sieves, but due to the large radius of hydrated ions, the exchange is difficult, and the uniformity of the exchanged products is not ideal. In order to improve this defect, salts containing rare earth elements can be added to the synthetic raw materials of molecular sieves. Make rare earth elements enter molecular sieves during crystallization

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Select the molar ratio of the reaction mixture as: SiO 2 / Al 2 o 3 =30,OH - / SiO 2 =0.20, (HMI+CHA) / SiO 2 = 0.3, La 2 o 3 / Al 2 o 3 =0.015,H 2 O / SiO 2 =32. The operation steps are: under the condition of constant stirring, 5.1g of sodium metaaluminate solution [containing 15.0% (w) Al 2 o 3 , 27.0% (w) NaOH, the same below], 0.44g sodium hydroxide (96% NaOH), 2.3g hexamethyleneimine, 4.3g cyclohexylamine, 56.0g silica sol [containing 24.1% (w) SiO 2 , the same below], 0.1g La(NO 3 ) 3 ·6H 2 O and 84.1 g of deionized water were sequentially added into a stainless steel reactor and mixed evenly, then the reactor was sealed and crystallized at 166° C. for 48 h. After the reaction kettle is cooled, the solid and the mother liquor are centrifuged, the solid is washed with deionized water to pH 8-9, and dried at 100°C in the air for 8 hours to obtain the original molecular sieve powder, which is tested by powder X-ray diffraction (XRD) The result is MCM-49 mo...

Embodiment 2

[0017] In embodiment 1, the add-on of sodium metaaluminate solution is changed into 255g, the add-on of sodium hydroxide is changed into 22g, the add-on of hexamethyleneimine is changed into 115g, and the add-on of cyclohexylamine is changed into 215g, the addition of silica sol is changed into 2800g, La(NO 3 ) 3 ·6H 2 The addition of O was changed to 5g, the addition of deionized water was changed to 4204g, and the raw material composition was unchanged. The raw material mixture was first aged at 40°C for 12 hours, and then crystallized at 172°C for 38 hours. The product was MCM-49 molecular sieve, and the La in the molecular sieve was measured by XRF. 2 o 3 The weight content is 0.21%.

Embodiment 3

[0019] In embodiment 1, the add-on of sodium hydroxide is changed into 0.67g, the add-on of hexamethyleneimine is changed into 3.5g, the add-on of cyclohexylamine is changed into 6.5g, the add-on of silica sol is changed into 28.0g, La(NO 3 ) 3 ·6H 2 The addition of O was changed to 0.13g, the addition of deionized water was changed to 97.3g, and the rest of the raw materials were unchanged; the molar ratio of the reaction mixture was: SiO 2 / Al 2 o 3 =15,OH - / SiO 2 =0.45, (HMI+CHA) / SiO 2 = 0.9, La 2 o 3 / Al 2 o 3 =0.02,H 2 O / SiO 2 =60. The raw material mixture was first aged at 85°C for 6 hours, and then crystallized at 148°C for 70 hours. The product was MCM-49 molecular sieve, and the La in the molecular sieve was measured by XRF. 2 o 3 The weight content is 0.28%.

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Abstract

The invention provides a method for preparing an MCM-49 molecular sieve containing rare earth. The molecular sieve comprises the following raw materials: an aluminum source, a base source, a silicon source, hexamethylene imine, cyclohexane, deionized water and salts of the rare earth, wherein the molar ratios of the raw materials comprise: SiO2:Al2O3 is 12-50, OH:SiO2 is 0.05-0.7, (HMI+CHA):SiO2 is 0.08-1.2, H2O:SiO2 is 10-70, and Re2O3:Al2O3 is 0.01- 0.5. The method comprises the following steps: putting the raw materials into a synthesizing kettle according to the ratios, and sealing the kettle; raising programming temperature to a crystallization temperature of between 135 and 180 DEG C; and then crystallizing and cooling the raw materials in self-generated pressure; and obtaining the MCM-49 molecular sieve containing the rare earth after a crystallized product is subjected to filtering, washing and drying. The method can improve the stability of a molecular sieve catalyst by introducing the rare earth into the molecular sieve in synthesizing, and obviously reduce the synthesizing cost by replacing partial or most of the hexamethylene imine by the cyclohexane in organic amine; meanwhile, the preparation method has the characteristics of good repeatability and high degree of crystallinity of the product.

Description

technical field [0001] The invention relates to a preparation method of rare earth-containing MCM-49 molecular sieve. Background technique [0002] MCM-49 molecular sieve is a molecular sieve first developed by Mobil Corporation (USP5,236,575), which has a MWW structure configuration. In the field of heterogeneous catalysis, MCM-49 molecular sieve can be used in various reaction processes including aromatization, isomerization and disproportionation, and has a good application prospect. [0003] At present, the template agent for synthesizing MCM-49 zeolite is basically hexamethyleneimine (HMI), although USP5,236,575 mentions in its claims that organic amines for synthesizing MCM-49 include cycloalkylamine (cycloalkylamine) The Chinese patent application number 02145238.5 also mentions that cycloheptaneamine, cyclohexaneamine and cyclopentaneamine can be used as templates for the synthesis of MCM-49, but there is no relevant experimental data. In fact, at present, it is di...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/02C01B37/00
Inventor 谢素娟张玲刘盛林朱向学陈福存徐龙伢
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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