关键词: SAPO-11, 多级孔, 干凝胶, CTAB, PEG

Abstract: The porous SAPO-11 molecular sieves were prepared by dry-gel method under the condition of single or simultaneous addition of cetyltrimethylammonium bromide (CTAB) and polyethylene glycol (PEG), respectively, with pseudoboehmite, silica sol and phosphoric acid as aluminum source, silicon source and phosphorus source, dipropylamine and diisopropylamine as template. The synthesized SAPO-11 molecular sieves were characterized by XRD, nitrogen physical adsorption and desorption, SEM, NH₃-TPD and Py-IR. The catalytic performance of the prepared Pt/SAPO-11 molecular sieve in n-dodecane isomerization reaction was investigated on a fixed bed. The results show that the addition of CTAB and PEG in the dry gel synthesis of SAPO-11 can promote the formation of mesoporous structure in the molecular sieve and change its morphology and acid strength. The selectivity and yield of the synthesized multistage pore SAPO-11 catalyst for n-dodecane hydroisomerization are significantly superior to those of the microporous SAPO-11 molecular sieve. The selectivity and yield of isoparaffin of Hier-Sapo-11-cp molecular sieve reach 71.2% and 62.1% respectively at 340 ℃.

Key words: SAPO11, Multistage Pore, Dry gel, CTAB, PEG