Method for preparing catalyst used for methanol/dimethyl ether high selectivity propylene preparation

Abstract

The invention provides a method for preparing a catalyst used for methanol / dimethyl ether high selectivity propylene preparation, and specifically provides a method for preparing nanometer layer structured ZSM-5 molecular sieve by employing an asymmetric gemini quaternary ammonium surfactant as a template. The method comprises specific steps as follows: (1) preparing solution A by adding the template to a mixed solution comprising water and ethanol, and preparing solution B by adding aluminum sources to sulfur solution; (2) slowly adding the B solution to the A solution, uniformly stirring the mixed solution comprising the A solution and the B solution, and then adding the aluminum sources to form initial gel; and (3) moving the gel to a crystallization kettle for crystallization under 100-200 DEG C for 1-10 days. A ZSM-5 molecular sieve prepared according to the invention is in a nanometer layer structure with the thickness being 20-100 nm, the silica-alumina ratio of the molecular sieve can be adjusted, and the specific surface area and the pore volume of the molecular sieve are quite large. In a methanol / dimethyl ether high selectivity propylene preparation reaction, the propylene selectivity and P / E ratio of the nanometer layer structured ZSM-5 molecular sieve are higher than that of a conventional ZSM-5 molecular sieve, and the service lifetime of the catalyst is longer.

Description

technical field [0001] The invention belongs to the field of synthesis and catalytic application of zeolite molecular sieve materials, and relates to a molecular sieve catalyst for methanol conversion to propylene production process, in particular to a nano-layer structure ZSM-5 molecular sieve used in methanol / dimethyl ether high-selectivity propylene production reaction Preparation method and reactivity. Background technique [0002] Propylene is an important basic petrochemical raw material. In recent years, driven by the rapid growth of demand for propylene derivatives such as polypropylene, acrylonitrile and propylene oxide, it has greatly promoted the rapid growth of world propylene demand. At present, the production of propylene in the domestic market mainly comes from the by-products of steam cracking to produce ethylene and the associated gas of catalytic cracking to produce gasoline. With the increasing depletion of petroleum resources and the rising international ...

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Problems solved by technology

However, the catalysts reported in these studies and patents are generally spherical or cubic, and the catalysts are less stable and have a shorter lifespan.

[0004] In 2009, NATURE reported a kind of gemini quaternary ammonium salt surfactant by means of asymmetric organic hydrocarbon chain, (molecular formula C 18 h 37 -N + (CH 3 ) 2 -C 6 h 12 -N + (CH 3 ) 2 -C 6 h 13 , abbreviated as C18-6-6), successfully synthesized a sheet structure ZSM-5 molecular sieve with a single unit cell thickness of 2 nm (Nature, 2009, 461(10): 246-250), which is different from the traditional spherical or cubic Compared with ZSM-5 molecular sieve, the material is a meso-microporous composite molecular sieve with large specific surface area and pore volume. The nanosheet structure makes the channel length short and the diffusion performance is very good. It has high carbon capacity in the reaction of making gasoline (MTG), which can improve the life of MTG catalyst, but there is no report on its product distribution in MTG reaction

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