磷酸铝分子筛的热稳定性研究

应用动态高温X射线衍射技术 ,研究了AlPO4 分子筛的热稳定性及随温度变化的X射线衍射峰强度 ,常温下考察了不同吸附时间下X射线衍射谱峰强度的变化。结果表明 ,A1PO4 分子筛作为催化剂载体的原始样品 ,在经高温预处理后 ,分解了残留在孔道内的有机物质和经脱附消除了水汽的影响 ,其结晶性能趋于最佳。在 90 0℃时骨架仍没有明显破坏 ,在 10 0 0℃时转化为磷铝致密相。AlPO4 分子筛吸附水汽并没有改变其基本的化学结构 ,此吸附过程是可逆的。此外 ,AlPO4 分子筛在低角区的X射线衍射谱峰强度对吸附水汽十分敏感

Study on Examination of Molecular Sieves Thermal Stability

By using the dynamic method, the thermal stability of molecular sieves AlPO_4 and the change of their X-ray diffraction peaks were examined at different temperatures. At room temperature the change of the adsorption subject to different time period was also performed. The experimental results show that as the original sample of the supporting material through pretreatment at high temperature, the organic materials in the holes in the AlPO_4 are destroyed and the water vapor is also removed from the holes in AlPO_4. The crystalline characteristics of AlPO_4 are optimarized. At 900 ℃, the frame of it is not destroyed apparently. But at 1 000 ℃, it changed into the another phase. That molecular sieve AlPO_4 absorbs water vapor does hot change their basic chemical structure, and the adsorption process is reversible. In addition, their intensities of low angle X-ray diffraction peaks are sensitive to adsorption of water vapor.