All-silicon molecular sieve and synthetic method thereof

Abstract

The invention provides an all-silicon molecular sieve and a synthetic method thereof. Q4 / Q3 of the all-silicon molecular sieve is (10-90):1, wherein Q4 is the peak intensity expressed by the peak height at the chemical shift of -112+ / -2ppm in a 29SiNMR spectrogram of the all-silicon molecular sieve, and Q3 is the peak intensity expressed by the peak height at chemical shift of -103+ / -2ppm in the 29SiNMR spectrogram of the all-silicon molecular sieve. The synthetic method of the all-silicon molecular sieve comprises the following steps: mixing a template agent, an organic silicon source, an inorganic ammonium source and water to be subjected to hydrolytic alcohol removal, aging the obtained product, mixing the aging product with a solid silicon source, crystallizing the mixture in a closed reaction kettle, and recovering the all-silicon molecular sieve. The all-silicon molecular sieve provided by the invention has higher activity in cyclohexanone-oxime beckmann rearrangement.

Description

technical field [0001] The invention relates to an all-silicon molecular sieve and a synthesis method thereof. Background technique [0002] All-silicon molecular sieves such as S-1, S-2, and β molecular sieves have no exchangeable cations on their skeletons, and their adsorption capacity for water molecules is far lower than that for organic molecules. They have high hydrophobicity and can be used as membranes. Separation materials and catalytic materials can also be used as parent materials for preparing other catalytic materials. For example, the all-silicon MFI structure molecular sieve S-1 has been used as a catalyst for the rearrangement of cyclohexanone oxime to prepare caprolactam; the research on the synthesis of molecular sieves with all-silicon S-1 molecular sieve and all-silicon beta molecular sieve as the matrix is ​​also in the ascendant, such as the synthesis of TS-1 molecular sieve and Sn-beta molecular sieve. [0003] In 1977, Union Carbide reported a meth...

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Problems solved by technology

Organic silicon sources such as organosilicon ester TEOS are relatively expensive, and the content of active ingredients forming molecular sieves is also low. It is difficult to increase the solid content of molecular sieve crystallization products, and a large amount of ethanol is volatilized during the production of molecular sieves, and these ethanols are difficult to collect. Reuse

In order to reduce costs, researchers have studied the use of inorganic silicon sources to replace part or all of organic silicon sources, but the activity of all-silicon molecular sieves synthesized using inorganic silicon sources is low

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