Method for synthesizing composite molecular sieve by microwave method and catalytic performance application thereof

A technology of composite molecular sieves and synthesis methods, which is applied in the field of microwave synthesis of composite molecular sieves and their catalytic properties, can solve the problems of few reports and achieve the effects of no temperature gradient and thermal stress, time saving, and good catalytic effect

Inactive Publication Date: 2011-04-06
JIANGSU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In recent years, mesoporous molecular sieve catalysts or ionic liquids have been widely used in phenol alkylation [K.Rajasekar et al., Catalysis Communication, 2007, 8:635-643], but there are few reports on composite molecular sieves as catalysts

Method used

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  • Method for synthesizing composite molecular sieve by microwave method and catalytic performance application thereof
  • Method for synthesizing composite molecular sieve by microwave method and catalytic performance application thereof
  • Method for synthesizing composite molecular sieve by microwave method and catalytic performance application thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Weigh 21.3gNa 2 SiO 3 9H 2 O was dissolved in 29ml distilled water, stirred evenly, and 0.82g NaAlO was added under vigorous stirring 2 , continued to stir for 2h, and then aged at room temperature for 2d to obtain the directing agent. Add 2.82g NaOH to 89ml distilled water, slowly add 9ml guiding agent, 20.23g sodium silicate, 4g metakaolin powder under magnetic stirring, so that the molar ratio of raw materials is: SiO 2 :Na 2 O:Al 2 o 3 :H 2 O=1:1.33:0.167:47, continue to stir vigorously for 2 hours, put into a 100ml stainless steel reactor with polytetrafluoroethylene lining, and crystallize in an oven at 100°C for 12 hours to obtain a microporous precursor. Dissolve 6.17g of CTAB in 22ml of distilled water, stir to a colloidal solution, slowly drop this solution into the microporous precursor, stir evenly, so that the molar ratio of the final material is: SiO 2 :Na 2 O:Al 2 o 3 :CTAB:H 2 O=1: 1.33: 0.167: 0.16: 58, continue to stir rapidly 2h, adjust pH...

Embodiment 2

[0031] According to the method of Example 1, the conditions such as raw material ratio are unchanged, only the microwave power is changed, and the synthesis is carried out according to the microwave power of 160W and 220W respectively. Figure 7 is the N of samples obtained under different microwave powers 2 Adsorption-desorption isotherm and pore size distribution diagram. Depend on Figure 7 It can be seen that the adsorption isotherm of the sample is Langmuir IV type, which is a typical adsorption isotherm of mesoporous materials, which indicates that the synthesized composite molecular sieve has a mesoporous structure, and the specific surface area of ​​the samples is greater than 500m 2 / g, in addition, the characteristic peak of mesoporous molecular sieve MCM-41 appeared on the small-angle XRD spectrum of the sample, and the diffraction peak of Y-type molecular sieve existed on the wide-angle XRD spectrum of the sample, indicating that the composite Molecular sieve.

Embodiment 3

[0033] According to the method of embodiment 1, keep the proportioning of other raw materials unchanged, only change the consumption of templating agent, respectively according to the molar proportion of raw material is SiO 2 :Na 2 O:Al 2 o 3 :CTAB:H 2 O=1:1.33:0.167:0.1:58 and the molar ratio of the final material is SiO 2 :Na 2 O:Al 2 o 3 :CTAB:H 2 O=1:1.33:0.167:0.3:58 was synthesized. Figure 8 It is the small-angle XRD spectrum of the synthesized sample. It can be seen that under the condition of changing the amount of template agent, the synthesized sample has the characteristic peak of mesoporous molecular sieve. In addition, wide-angle XRD diffraction also confirms that the sample has the characteristic peak of Y-type molecular sieve, indicating that Composite molecular sieves were synthesized with template dosage within a certain range.

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Abstract

The invention discloses a method for synthesizing a composite molecular sieve by a microwave method and catalytic performance application thereof. In the method for preparing the composite molecular sieve by the microwave method, kaolin is taken as a raw material, inorganic silicate is taken as an additional silicon source, and the prepared composite molecular sieve is applied to the alkylation reaction of phenol and tertiary butanol. The method comprises the following steps of: adding a certain amount of sodium silicate into the kaolin serving as the raw material to synthesize a Y type molecular sieve precursor; and preparing a composite molecular sieve Y/MCM-41 by the microwave method by using hexadecyl trimethyl ammonium bromide serving as a template. The synthesized molecular sieve has two pore structures, namely micropores and mesopores; the specific surface area of a sample is more than 550 m<2>/g; the average pore size is roughly 2.7 nm; and the sample has a regular and ordered hexagonal pore structure. The synthesized molecular sieve has good catalytic effect on the alkylation reaction of the phenol and the tertiary butanol, and particularly the selectivity of 4-tertiary butyl phenol is up to 86.3 percent.

Description

technical field [0001] The invention relates to a method for synthesizing composite molecular sieves by microwave method using cheap kaolin as raw materials, in particular referring to using kaolin and inorganic silicate as raw materials and hexadecyltrimethylammonium bromide as template agent to synthesize composite molecular sieves by microwave method , and it was applied to catalyze the alkylation reaction of phenol with tert-butanol. Background technique [0002] Composite molecular sieve is a new type of molecular sieve developed on the basis of mesoporous molecular sieve. It has two kinds of pore distributions: mesopore and micropore. Stability makes the advantages of the two materials complement each other, thereby overcoming the shortcomings of mesoporous molecular sieves or microporous molecular sieves used alone in industrial applications. Composite molecular sieves have high acidic and hydrothermal stability, which make them have broad application prospects in pe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J29/80B01J37/34B01J29/08B01J29/70C07C37/16C07C39/06
CPCY02P20/52
Inventor 赵谦李艳慧姜廷顺周旭平吴多林
Owner JIANGSU UNIV
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