三氢化铝乙醚配合物的稳定性及其固相转晶制备α-三氢化铝

针对不同贮存时长三氢化铝醚合物能否转晶制备α-三氢化铝问题进行了深入研究。 本文采用传统法制得三氢化铝醚合物并在氮气气氛下储存1~20 d,然后基于此三氢化铝醚合物,采用固相、真空转晶技术制备α-三氢化铝。 X射线衍射(XRD)、热重分析(TGA)和扫描电子显微镜(SEM)分析表明,随着醚合物贮存时间的延长,其乙醚成分逐渐降低,贮存10 d仍然可以制备出纯度较高的α-三氢化铝,然而10 d后,有γ-三氢化铝产生,而且产物粒径变小。 证明醚合物中乙醚的含量多少与制备出的α-三氢化铝的品质有直接关联。 制备过程摒弃有毒试剂甲苯,也为α-三氢化铝的千克级制备提供了一种可能。

Stability of Aluminum Hydride Etherates and Its Solid-State Conversion to Alpha-Aluminum Hydride

The problem of whether α-AlH₃ crystallized by aluminum hydride etherates(AlH₃·nEt₂O) stored for varying time is systematically studied. First, AlH₃·nEt₂O was prepared by a conventional method and stored under a nitrogen atmosphere for 1 to 20 days, and then α-AlH₃ was prepared by a solid phase and vacuum crystallizing technique based on the AlH₃·nEt₂O. XRD, TGA and SEM analysis show that the ether composition gradually decreases during storage and α-AlH₃ with higher purity can be prepared within 10 days of storage. However, after 10 days, γ-AlH₃ with smaller particle size appeared. Finally, we confirm that the amount of ether in AlH₃·nEt₂O is directly related to the quality of prepared α-AlH₃. Another highlight of this paper is the abandonment of the toxic reagent toluene used in conventional processes. This also provides a possibility for the kilogram preparation of α-AlH₃.