摘要
AlPO_4-5是一种新型多孔磷铝分子筛晶体.由于骨架中不存在SiO_4四面体,PO_4^+AlO_4^-四面体交替排列,骨架呈电中性。Lok等首先报道了磷酸硅铝分子筛(SAPO)的合成.目前已有十几种元素同晶取代的AlPO_4-5分子筛.由于同晶取代,使得电中性的AlPO_4-5分子筛骨架呈电性和离子交换性。
SAPO-5 molecular sieves are synthesized by using a non-alkaline medium containing fluoride anions. The existence and homogeneity of framework silicon ?.re evidenced by XRD, electron probe micro analysis (EPMA) and 29Si MASNMR. Pyridine adsorption IR spectra and cumene cracking activity data indicate that different amounts of silicon substituted show no distinct effect on the surface acidity and catalytic activity. The activity decay of the samples is very slow, this is evidence to prove that one Si substitution for one P and two Si substitution for one Al and one P happen at the same time.
