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AlPO_4-5胶体加有机胺后,原来生成的三种结晶磷酸盐结构被破坏而生成无定形胶体。加热晶化,取不同晶化时的样品用X射线衍射、差热和电镜等手段考察了体系变化的情况。结果发现,晶化0～4小时这一段时间内体系变化较大。X射线衍射图谱中各晶面衍射峰出现有一定先后次序,即(100)晶面衍射峰首先出现而且较强,其它晶面滞后。差热谱在0～4小时内,在250℃左右出现一个脱胺峰,随着晶化时间加长消失,而在360～380℃出现一个脱胺峰。由以上结果分析认为:AlPO_4-5分子筛的成晶过程可概括为下述模式:(1) 沿(100)晶面Al、P迅速地从侧面接近晶面,生成共价键;(2) 有机胺分子从正面接近晶面,吸附在表面上,Al、P再从正面靠近晶面与晶面组元成键,使有机胺分子夹在晶面之间;(3) 平行晶面间松散的价键过渡到正常的共价键,形成稳定晶格。结合上述模型和四种不同有机胺对晶化作用的考察,认为有机胺的模板作用过程可分为二步,首先是有机胺分子在晶面上的吸附,其次是空间立体效应。
AlPO_4-5 colloid plus organic amine, the original three kinds of crystalline phosphate structure is destroyed to generate amorphous colloid. Heating crystallization, taking different crystallization of the sample with X-ray diffraction, differential scanning electron microscopy and other means to examine the system changes. The results showed that the crystallization of 0 to 4 hours during this period of system changes. X-ray diffraction pattern of each crystal diffraction peak there is a certain order, that (100) crystal diffraction peaks first appeared and stronger, the other crystal face lag. The differential thermal profile showed a deaminated peak at 250 ° C within 0-4 hours, disappearing as the crystallization time lengthened, and a deamination peak at 360-380 ° C. From the above results, it is concluded that the crystallization process of AlPO 4 -5 zeolite can be summarized as follows: (1) Al and P along the (100) plane rapidly approach the crystal plane from the side and form covalent bonds; (2) Amine molecules from the front close to the crystal plane, adsorbed on the surface, Al, P and then from the front close to the crystal plane and crystal plane component bonding, so that organic amine molecules sandwiched between crystal planes; (3) The valence bond transitions to a normal covalent bond to form a stable lattice. Combined with the above model and the investigation of the crystallization of four different organic amines, the template process of organic amines can be divided into two steps. The first is the adsorption of organic amine molecules on the crystal plane, followed by the spatial three-dimensional effect.