ZSM-5 molecular sieve containing phosphorus in crystal, synthetic method and application thereof

Abstract

The invention discloses a synthetic method of ZSM-5 molecular sieve containing phosphorus in crystal. The method comprises the following steps: (1) quaternary ammonium hydroxide and tetrabutylphosphonium hydroxide and an aluminium source are mixed, a mixture is treated in an enclosed reaction vessel for 0.1-5 hours at 50-190 DEG C and cooled, an intermediate product is obtained, and an aluminium source is an aluminium source without alkali metal ions; (2) the intermediate product in the step (1) and a silicon source and water are uniformly mixed in order to obtain a mixture; (3) the mixture in the step (2) is placed in the enclosed reaction vessel for hydrothermal crystallization and products are recycled. The synthesized ZSM-5 molecular sieve containing phosphorus in crystal can be used as an active component for catalysis of tetradecane with higher cracking conversion rate.

Description

technical field [0001] The invention relates to a phosphorus-containing ZSM-5 molecular sieve, a synthesis method and its application, more specifically to a phosphorus-containing ZSM-5 molecular sieve in crystals, a synthesis method of an alkali-free metal system and its application. Background technique [0002] ZSM-5 molecular sieve is a high silicon medium pore molecular sieve with MFI structure. It has a unique pore structure and is widely used in important petrochemical units such as catalytic cracking, aromatization, and alkylation. Phosphorus-modified ZSM-5 has good catalytic performance, high thermal stability and hydrothermal stability, and is widely used in catalytic cracking, alkylation and other reaction processes. [0003] The synthesis system of ZSM-5 molecular sieves usually uses inorganic bases (such as sodium hydroxide) to form an alkaline environment suitable for the crystallization of molecular sieves. The synthesized molecular sieves are sodium-type ZSM-...

AI Technical Summary

Problems solved by technology

[0007] Nichiappan lingappan et al. (Bull.Chem.Soc.Jpn, 1996,69,1125-1128) used quaternary phosphorus salts as templates and roasted them after synthesis to obtain phosphorus-containing ZSM-5 molecular sieves, wherein the phosphorus content was between 0.4 and 0.6wt% range, but quaternary phosphorus salts are usually prepared by reacting trisubstituted phosphorus with hydrohalic acid, and the price is high

The addition of chloride ions in molecular sieves will affect the stability of molecular sieves, thereby affecting the catalytic activity of molecular sieve catalysts