Synthesis method for Silicalite-1 molecular sieve

Abstract

The invention discloses a synthesis method for a Silicalite-1 molecular sieve, wherein the method comprises the following steps: (1) mixing evenly a silicon source, a structure directing agent and water with an optionally alkali source, to obtain a reaction mixture with the molar ratio of SiO2 to R to OH<-> to H2O of 1 to (0.05-0.39) to (0.05-2) to (2-100), wherein R represents the mole number of the structure directing agent, and the structure directing agent is at least one selected from the group consisting of tetraethylammonium hydroxide, tetraethylammonium bromide, tetraethylammonium chloride, tetraethylammonium fluoride, tetraethylammonium iodide and triethylamine; (2) according to the molar ratio of a mineralization agent to OH<-> of (1-5) to 1, adding the mineralization agent to the reaction mixture obtained in the step (1), stirring evenly, crystallizing for 0.5-60 days at the temperature of 80-200 DEG C and at the self-generated pressure, to obtain a crystallized product; and (3) recycling the crystallized product obtained in the step (2). By the synthesis method, the Silicalite-1 molecular sieve with perfect and uniform crystal grains and fewer skeleton defects can be synthesized under the action of the novel structure directing agent.

Description

technical field [0001] The invention relates to a synthesis method of Silicalite-1 molecular sieve. Background technique [0002] ZSM-5 is a molecular sieve with MFI topology developed by Mobil Corporation in the 1970s. It has a two-dimensional ten-membered ring channel structure, in which the [100] direction is a straight channel with a pore size of 0.51×0.55 nm, and the [010] direction is a sinusoidal channel with a pore size of 0.53×0.56 nm. The Si / Al ratio of ZSM-5 can be changed in the range of silicon-rich and full-silicon, which has good adjustability. [0003] Due to its special two-dimensional ten-membered ring channel structure and acid catalytic performance, ZSM-5 has become one of the most important molecular sieve catalytic materials. At present, ZSM-5 molecular sieve has been widely used in petrochemical, coal chemical and fine chemical fields such as catalytic cracking, alkylation, isomerization and methanol to olefins. Therefore, the synthesis and modifica...

AI Technical Summary

Problems solved by technology

Therefore, the synthesis of molecular sieve Silicalite-1 reported in the current literature is actually carried out under the guidance of tetrapropylammonium, and no templates with other structures have been used for the synthesis of Silicalite-1.

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