The Effects Of Aluminium Sources On The Synthesis Of SAPO-11 Molecular Sieves

SAPO-11 is a kind of microporous silicoaluminophosphate with AEL topology which has 10-MR one-dimensional elliptical straight channel. It exhibits high stability and strong acidity properties and therefore is widely used in petrochemical industry. Previous studies revealed that the specific surface areas of aluminum sources had an important influence on the synthesis of SAPO-11 molecular sieves. UOP listed aluminium isopropoxide and pseudo-boehmite as aluminum sources in the patent of the earliest synthetic SAPO-11 molecular sieves. But the effects of aluminium sources on the synthesis of SAPO-11 molecular sieves have rarely been systematic researched.In this paper, we chose a new self-made nanosheet silica-doped pseudo-boehmite with large specific surface area and pore volume as aluminum source and silicon source simultaneously to synthesis SAPO-11 molecular sieves. Then we investigated the influences of different factors, such as the composition, hydrofluoric acid, the crystallization time and crystallization temperature. Moreover, we study that the effect of peptization on the synthesis of SAPO-11 molecular sieves.The effects of aluminium sources on the synthesis of SAPO-11 molecular sieves were studied under hydrothermal conditions in this paper. And the products were characterized by XRD?SEM?BET?STA. The results indicate that the synthesized SAPO-11 molecular sieves synthesized with self-made nanosheet silica-doped pseudo-boehmite as aluminium source has high crystal linity, and the microporous surface area of the product can reach up to 231.4 m2/g, which is higher than the highest 181 m2/g reported in the literature. Its stucture collapse temperature is 1197?, which is much higher than 900? described in the literature. Therefore, compare with industrial pseudo-boehmite, the SAPO-11 molecular sieves synthesized with self-made nanosheet silica-doped pseudo-boehmite as aluminium source has high crystallinity, large specific surface areas and good thermal stability.