The invention provides a preparation method of a silicoaluminophosphate
molecular sieve with a hierarchical pore structure. The method comprises the steps: firstly, by adopting
tetraethyl orthosilicate or silica
sol as a
silicon source, pseudo-
boehmite or aluminum isopropoxide as an aluminum source, orthophosphoric acid as a
phosphorus source, and
triethylamine,
tetraethylammonium bromide or
tetraethylammonium hydroxide as a template agent, uniformly stirring the
silicon source, the aluminum source, the
phosphorus source, the template agent and deionized water, performing hydrothermal
crystallization treatment, and then centrifuging to obtain supernatant liquor; secondly, uniformly stirring the
silicon source, the aluminum source, the
phosphorus source, the template agent and the supernatant liquor, performing hydrothermal
crystallization treatment, and filtering to obtain a
filter cake and filtrate; thirdly, sequentially washing,
drying and
roasting the
filter cake, and naturally cooling to obtain the silicoaluminophosphate
molecular sieve with the hierarchical pore structure. The prepared silicoaluminophosphate
molecular sieve provided by the invention has an obvious hierarchical pore structure, greatly shortens the
diffusion path, improves the acid site
accessibility, significantly prolongs the service life, and has very important practical values in reaction of preparing olefin from
methanol.