预先负载原料法的制备过程对复合分子筛形成的影响

采用预先负载原料法合成了具有核/壳结构的复合分子筛, 并研究了铝源类型和制备过程对反应的影响. 结果表明, 以异丙醇铝为铝源时, 晶化时间较短, 产物中没有SAPO-5晶体, 延长晶化时间可以提高SAPO-5的结晶度. 将负载磷的ZSM-5分别与不同组成的凝胶混合, 经室温陈化后可以明显加快晶化速度. 制备过程中凝胶的水含量和搅拌方式也根据铝源类型的不同有所差别. 当以拟薄水铝石为原料时, 在相同的处理条件下, 产物的结晶度都较高.

Effect of Preparation Process on the Synthesis of Composite Molecular Sieves by Pre-loading Raw Method

The core/shell binary structure composite molecular sieves have been synthesized by loading raw materials method. The effects of types of aluminium source and preparation process were investigated. The synthesized samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and energy dispersive spectrometry(EDS). Using iso-propanol aluminum as the aluminium source, there is no SAPO-5 phase in short crystallization time; prolonging crystallization time increases the crystallinity of SAPO-5; the aging of the different reaction mixture at room temperature can cause a rapid formation of SAPO-5 sieve. The choice of the content of water in gel and mixing manners are dictated by types of aluminium source. Using pseudoboehmite as aluminium source, at the same pretreated temperature of coating phosphorus and preparation process, the sieve with higher degree of crystallinity was obtained.