Synthesizing hierarchically porous SAPO-11 with polyvinyl alcohol phosphates as mesopore template: effects of phosphorus content and concentration of templates

Introducing the second mesopores into SAPO-11 molecular sieve will be much helpful to improve the catalytic performance of its metal-supported catalysts in hydroisomerization of normal alkanes. In current paper, polyvinyl alcohol phosphates with different phosphorus contents were prepared and employed as mesopore template to prepare hierarchical SAPO-11. The effects of phosphorus content and concentration on the properties including mesopore structure, acidity and morphology of the prepared SAPO-11s have been investigated. The results showed that with appropriate phosphorus content and template concentration, PPVAs efficiently directed the generation of regular mesopore structure, extended the surface area and improved the acidity of the SAPO-11 molecular sieves. Pt/SAPO-11 bi-functional catalysts were prepared and their catalytic performances in hydroisomerization of n-hexane were evaluated. The highest conversion read 59.3%, while the optimal selectivity of branched hexanes was 86.5%.