Method for synthesizing nano GaZSM-5 silicon gallate molecular sieve through dry glue conversion method

Abstract

The invention discloses a method for synthesizing nano GaZSM-5 silicon gallate molecular sieve through dry glue conversion method, and aims to solve the problems of an existing ZSM-5 molecular sieve hydrothermal synthesis method that the crystallization time is long, the environment is polluted due to emission of waste liquid, and the particle diameter of the molecular sieve is large. The method for synthesizing the nano GaZSM-5 silicon gallate molecular sieve through the dry glue conversion method comprises the following steps: 1, weighing raw materials; 2, adding a tetrapropylammonium hydroxide water solution and deionized water in gallium oxide, and heating for reacting, thus preparing a reaction solution; 3, dropwise adding ethyl orthosilicate into the reaction solution, thus preparingmixed gel; 4, stirring the mixed gel under the condition that the rotating speed is 300 to 500 r / minute; 5, adding dry glue into a closed reaction kettle, carrying out solid-phase crystallization reaction at 160 to 185 DEG C, and drying, thus obtaining the nano GaZSM-5 silicon gallate molecular sieve. According to the method disclosed by the invention, the crystallization time of the dry glue conversion method is short, no wastewater is discharged, Ga atoms can successfully enter a molecular sieve framework, and the size of a single crystal grain is about 20 to 30 nm.

Description

technical field [0001] The invention belongs to the field of preparation of zeolite molecular sieve catalysts, in particular to a preparation method of nanometer GaZSM-5 silica gallate molecular sieves. Background technique [0002] As a very important shape-selective catalyst, ZSM-5 molecular sieve is suitable for shape-selective alkylation, toluene disproportionation, methanol to olefins and Gasoline (MTG) and other acid-catalyzed reactions have been widely used. The nano ZSM-5 molecular sieve exhibited higher catalytic activity and stability due to its larger external area and more accessible acid sites. However, nano-ZSM-5 aluminosilicate molecular sieves have high acid strength, and carbon deposition is prone to occur in the above acid-catalyzed reactions, leading to catalyst deactivation. In order to weaken the acid strength of ZSM-5 molecular sieves, a second metal active component is usually introduced to prepare bifunctional catalysts. Ga atoms were introduced in...

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Problems solved by technology

[0003] The present invention aims to solve the problem that a large amount of waste water containing alkali and nitrogen-containing organic matter is produced in the process of synthesizing GaZSM-5 molecular sieve by the existing traditional hydrothermal method, and the particle size of the synthesized molecular sieve is large, which leads to poor mass transfer ability when used as a catalyst. , so as to provide a new green synthesis method for preparing nano-GaZSM-5 gallosilicate molecular sieves by dry gel solid phase conversion method

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