Synthesis method of SAPO-34 molecular sieve

Abstract

The invention provides a synthesis method of a SAPO-34 molecular sieve. According to the synthesis method, phosphoric acid is taken as the phosphor source; silica sol is taken as the silicon source; triethylamine is taken as the template; at first, the silicon source is pre-heated for 3 to 4 hours at a temperature of 200 DEG C by using phosphoric acid; then a mixture of an aluminum source, a phosphor source, and a silicon source, an organic template, and water are used to prepare synthesized gel, wherein the mole ratio of Al2O3: H3PO4: SiO2: R: H2O is 1.0: 2.0: (0.05-2.0): 3.0: (50-150); the synthesized gel is subjected to hydrothermal crystallization for 1 to 2 days at a temperature of 200 DEG C under a self-generated pressure; and finally the synthesized gel is cooled, washed by water, separated, and dried at a room temperature to obtain the molecular sieve. The silicon distribution of provided SAPO-34 molecular sieve is more even.

Description

[0001] 1. Technical field [0002] The invention relates to a method for synthesizing SAPO-34 molecular sieves. Specifically, silicon sources are heat-treated with phosphoric acid, and then triethylamine is used as a template to synthesize SAPO-34 molecular sieves with uniform silicon distribution. [0003] 2. Background technology [0004] Silicoaluminophosphate molecular sieve SAPO-34 made of PO 4 , AlO 4 and SiO 4 The tetrahedron constitutes a three-dimensional framework structure, and the SAPO-34 molecular sieve has a medium-strength acid center and an eight-membered ring microporous structure, which shows excellent catalytic performance in the reaction of methanol to light olefins. [0005] However, in the SAPO-34 molecular sieve synthesis system, the solubility of the silicon source is relatively poor, especially when the silicon content is high, the silicon component is easy to enter the SAPO-34 molecular sieve structure in the form of "silicon islands" of different si...

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Problems solved by technology

[0005] However, in the SAPO-34 molecular sieve synthesis system, the solubility of the silicon source is relatively poor, especially when the silicon content is high, the silicon component is easy to enter the SAPO-34 molecular sieve structure in the form of "silicon islands" of different sizes, making It is difficult to control the content and shape of the silicon component entering the SAPO-34 molecular sieve, resulting in uneven distribution of the silicon component, resulting in unstable catalytic performance of the SAPO-34 molecular sieve

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