AIPO_4-12的热分析研究

STUDY ON THE THERMAL ANALYSIS OF ALUMINOPHOSPHATE MOLECULAR SIEVE AlPO_4-12

用水热法在乙二胺-Al_2O_3-P_2O_5-H_2O体系中合成磷酸铝分子筛AlPO_4-12.晶化产物用X-射线粉末衍射分析,扫描电子显微镜观测和化学分析法进行表征.所得产物为纯的AlPO_4-12.热分析结果表明,AlPO_4-12分子筛可能具有孔径大小和/或结构不同的两种孔道体系,填充于小孔道内的有机模板剂需要在高温下或较长时间的低温下处理才可完全脱除.～450℃为适宜的脱胺温度,可使晶体结构不发生破坏.420℃下热处理≥18hr可基本脱除AlPO_4-12中的有机胺.

The aluminophosphate molecular sieve AlPO_4-12 was synthesized by hydrothermal method in the System of Ethylenediamine (C_2H_8N_2)-Al_2O_3-P_2O_5-H_2O. The Crystalline Product was characterized by X-ray powder diffraction analysis,scanning electron microscopy,and chemical analysis. The product obtained is a pure AlPO_4-12. Thermoanalytical results show that AlPO_4-12. probably consists of tow kinds of channel systems with different pore sizes and/or different structures. The organic template molecules present in the smaller channel will be removed completely only when A1PO_4-12 samples are treated at higher temperature or calcined at lower temperature for a longer time. The suitable temperature of removing ethylenediamine molecules is about 450℃,and the framework structure of AlPO_4-12 is stable at such temperature. The organic template (ethylenediamine) molecules present in A1PO_4-12 can be removed to a great extent when the sample is thermally treated for≥18hr at 420℃.