Synthesis, Characterization and Hydroisomerization Performance of SAPO-11 Molecular Sieves with Caverns by Polymer Spheres
Silicoaluminophosphates SAPO-11 molecular sieves with caverns were synthesized using polystyrene (PS) micro-spheres as template. The morphologies of the cavitary SAPO-11 molecular sieves exhibit spherical particles ranging 7–10 μm aggregated from cubic plate microcrystallites which just like the SAPO-11 molecular sieves synthesized with the conventional method, but some caverns of 500–1,200 nm pore size in diameter can be observed on the former material. The strength and distribution of the acid sites of the cavitary SAPO-11 are similar to that of the conventional SAPO-11, but the acid density is slightly low owing to the decreased crystallinity of the cavitary SAPO-11. The micropores size and mesopores size of the conventional SAPO-11 are centered at about 0.45 and 3.8 nm, respectively, while the cavitary SAPO-11 has, in addition to the micropores and mesopores, large mesopores ranging 5–30 nm and macropores ranging from about 100 to 1,200 nm, which were derived from the PS sphere template. Hydroisomerization of n-hexadecane was performed to investigate the catalytic performance of the cavitary SAPO-11. The result showed that, in comparison with the conventional SAPO-11, the cavitary SAPO-11 has high activity based on per active site and high selectivity, owing to the fast diffusion of the reactant and isomer products inside the catalyst.
KeywordsSAPO-11 molecular sieves Polymer spheres Caverns Hydroisomerization n-Alkanes
This research work was supported by the National Basic Research Program of China (Grant No: 2004CB217808).
- 1.Lok BM, Messina CA, Patton RL, Gajek RT, Cannan TR, Flanigen EM (1984) US Patent 4,440,871Google Scholar
- 13.Wang ZM, Yan ZF (2001) Acta Pet Sin (Pet Process Sect) 17:76Google Scholar
- 16.Wang XD, Yi GY (2007) Chem J Chin Univ 28:1759Google Scholar
- 18.Wang XD, Dong P, Yi GY (2006) Acta Phys Sin 55:2092Google Scholar
- 19.Khaja Mastan S, Rama Rao KS, Sai Prasad PS, Kanta Rao P (1992) Adsorp Sci Technol 9:212Google Scholar
- 22.Wang XD (2006) Research on floating assembly of colloidal particles and preparation of macroporous catalytic materials. China University of Petroleum, Beijing, p 59Google Scholar
- 26.Thomas JM, Thomas WJ (1997) Principles and practice of heterogeneous catalysis. VCH, New York, p 46Google Scholar