Nanometer sn-β molecular sieve and its preparation method and the method of phenol hydroxylation reaction

Abstract

The present invention relates to the technical field of β molecular sieves, and discloses a nano-Sn-β molecular sieve and a preparation method thereof and a method for phenol hydroxylation reaction. The preparation method of the nano-Sn-β molecular sieve comprises the following steps: (1) in the presence of an aqueous solvent , mixing the silicon source, the tin source, the structure directing agent and the alkali source to obtain a mixed solution, adjusting the pH value of the mixed solution to 9.5-13.8, performing a crystallization reaction on the mixed solution, separating and roasting to obtain a crystallized product; (2 ) mixing the crystallization product, cobalt salt and / or nickel salt in an aqueous solvent in proportion to obtain a reaction solution, and reacting the reaction solution at a temperature of 180-220° C. for 2-10 hours to obtain a molecular sieve precursor; (3 ) mixing the molecular sieve precursor and the sulfur-containing medium in an aqueous solvent, and performing a hydrothermal reaction to obtain a nano-Sn-β molecular sieve. The composite nano Sn-β molecular sieve is prepared by the above method, and the product has uniform particle size, large specific surface area and few skeleton defects, and has good catalytic performance in phenol hydroxylation reaction.

Description

technical field [0001] The invention relates to the technical field of beta molecular sieves, in particular to a nanometer Sn-beta molecular sieve, a preparation method thereof, and a phenol hydroxylation reaction method. Background technique [0002] Heteroatom molecular sieves refer to molecular sieves with non-silicon and aluminum elements in their skeleton structure. The introduction of heteroatoms not only regulates the acidity and surface properties of zeolite catalysts, but also makes them have special catalytic properties. Titanium-silicon molecular sieve TS-1 is a molecular sieve with a four-coordinate titanium framework, and its appearance marks the beginning of the synthesis and application of heteroatom molecular sieves. [0003] β molecular sieves are stacking fault symbiosis composed of three structurally distinct but closely related polymorphs. It has a three-dimensional twelve-membered ring channel structure, in which the channels in the [100] and [010] dire...

AI Technical Summary

Problems solved by technology

Phenol hydroxylation is the main method for preparing catechol and hydroquinone. This method mainly uses titanium-silicon molecular sieve TS-1 as a catalyst, but because its pore size is only about 0.55 nanometers, the diffusion of reaction products is inhibited. They Easy deep oxidation to generate quinone

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