Method for preparing high-stability mesoporous molecular sieve

Abstract

The invention provides a method for preparing a high-hydrothermal-stability mesoporous molecular sieve. The method includes the following steps: (1) preparation of a first Y-type molecular sieve precursor; and (2) crystallization: adding a seed crystal to the first Y-type molecular sieve precursor, adjusting the pH value to 0.5-5, stirring for 10 h-24 h at the temperature of 20 DEG C-50 DEG C, then aging for 2 h-24 h at the temperature of 20 DEG C-50 DEG C, to obtain an assembled product, transferring the assembled product into a microreactor with a polytetrafluoroethylene lining, then transferring together with the reactor into a high-pressure reaction kettle, crystallizing for 10 h-48 h at the temperature of 100 DEG C-200 DEG C, filtering, washing, drying, and thus obtaining the high-stability mesoporous molecular sieve. Firstly, the microporous molecular sieve precursor is prepared, a mesoporous-microporous molecular sieve as the seed crystal is used for preparation of the mesoporous molecular sieve, the molecular sieve precursor assembly method and the seed crystal method are combined, and the high-stability mesoporous molecular sieve is obtained under the condition without use of an organic template agent. Not only is the preparation cost of the molecular sieve reduced greatly, but also the process of calcination of the template agent is omitted so as to reduce the energy consumption.

Description

technical field [0001] The invention relates to a preparation method of a high-stability mesoporous molecular sieve, belonging to the technical field of catalysts. Background technique [0002] Since mesoporous molecular sieves were first reported by the Moblil company of the United States in 1992, scholars at home and abroad have done a lot of work to improve their stability and acidity. For example, Zhao Dongyuan et al. used P123 as a template to collectively call a highly stable SBA-15 molecular sieve under acidic conditions, and Pinnavaia et al. used the method of assembling microporous molecular sieve precursors to greatly improve the acidity and stability of mesoporous molecular sieves. Although these works have pushed mesoporous molecular sieves towards industrial applications, reducing the preparation cost of mesoporous molecular sieves is the key to realizing the industrial application of mesoporous molecular sieves, and templates account for more than 70% of the pr...

AI Technical Summary

Problems solved by technology

The seed crystal selected in this invention is a microporous molecular sieve, which is added to the preparation system after silanization, and its hydrophobicity is used to increase its effect on the hydrophobic end of the surfactant micelle, thereby reducing the interaction between the two directing agents. However, the formed mesopores still do not have a regular structure, and whether the addition of seed crystals reduces the amount of templating agent has not been reported.

[0015] Bao X., et al, AIChE Journal.54 (7): 1850-1859 (2008) disclosed a preparation method for preparing micro-mesoporous molecular sieves. Specifically, the precursor of Y-type molecular sieves was prepared first, and P123 was used as a template for its preparation. Carry out assembly to prepare highly stable mesoporous molecular sieves, but the yield of mesoporous molecular sieves prepared by this method is only 2%, and the template agent required for preparing molecular sieves is 2g P123 / g molecular sieves, and its preparation cost is higher

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