NaAl(NH_2)_4的热解过程研究

Pyrolysis Process of NaAl(NH_2)_4

通过NaAlH_4与液氨反应成功制备出NaAl(NH_2)_4,并利用XRD与FT-IR对其进行了表征。其次,通过热分析、XRD、FT-IR以及对制备样品不同温度热处理产物物相分析等方式对NaAl(NH_2)_4的热解过程进行了研究,实验结果表明:NaAl(NH_2)_4在68℃时开始缓慢发生分解放出NH3,250℃时热解基本完成,共放出约2倍摩尔量的NH3。中间产物Na Al(NH)2为非晶态,并在113.76℃左右发生分解。NaAl(NH_2)_4中[NH2]--Al键,N-H键均为共价键,热解过程,[NH_2]^--Al键先行断裂从而生成NH_3,NaAl(NH_2)_4最终热解产物为Na NH_2、Al N并伴随NH_3的生成。

The NaAl（NH2）4 was prepared from Na Al H4 reacting in liquid ammonia at low temperature. The decomposition process of the NaAl（NH2）4 were studied by thermoanalysis, XRD pattern and FT-IR, and product analysis of as-prepared samples with different-temperature heat treatments. Results show that the thermal decomposition of NaAl（NH2）4 under primary vacuum leads to the release of NH3 and ends at 250 ℃with two moles of NH3 releasing. Meanwhile, intermediate NaAl（NH）2 is amorphous and decomposed at about 113.76 ℃. In the complex NaAl（NH2）4, [NH2]-is covalently bonded with Al, and the same to N-H bond. In the pyrolysis process, [NH2]^--Al bond is prior to break up, which leads to the formation of NH3. The final pyrolysis products of NaAl（NH2）4 is NaNH2, Al N and NH3.