杂原子(Si)等比取代骨架P和Al时AlPO4-5型分子筛结构的研究

Study on the Structure of AlPO4-5 Type Molecular Sieve in the Framework P and Al Substituted Equal-Proportionally by Hetero-Atom(Si)

应用多晶X-射线衍射法研究了SAPO-5型分子筛结构,并经Rictveld法修正。结构测定得出,平均每个晶胞3.13个Si原子等比取代P和Al进入骨架,但仍保持APO-5型分子筛的对称性和几何构型。Si在骨架中与P、Al基本上成无序排列,从而使分子筛骨架不带电荷,在[001]方向也失去极性。因此若Si原子等比取代骨架中的P和Al,对调节APO-5分子筛的催化性能不会有显著作用。

The structure of Si-APO-5 type molecular sieve synthesized by us was investi-gated by X-ray diffraction for polycrystalline and the parameters were refined by Rietveld method.We discovered,although in average each unit cell 3.13 silicon atoms substituted equal-proportionally P,Al and entered framework of molecular sieve,SAPO-5 sample(10900)still keepcd the same symmetry and geometric configuration as APO-5.In addition to,the arrange of Si,P,Al in the framework were disorder on the whole,therefore,framework of molecular sieve lost polarity along[001]and cann't carry charge.So as Si atom substituted Pand Al atoms in framework equnl-proportionally,catalytic functions of APO-5 type molecular sieve cann't be outstanding adjusted.