Authors: Long V Dinh Douglas A Knight Mark Paskevicius Craig E Buckley Ragaiy Zidan
Publish Date: 2012/02/10
Volume: 107, Issue: 1, Pages: 173-181
Abstract
Many of the current synthesis methods for aluminum hydride alane—AlH3 involve reacting AlCl3 and LiAlH4 in solvents The reaction requires the formation of an alane adduct such as AlH3⋅C2H52O prior to obtaining crystallized stable αAlH3 This process requires several hours of pumping in a vacuum system to remove the ether and convert the alane etherate into stable αalane This crystallization process is both costly and hazardous because a large amount of highly flammable material eg ether is removed by vacuum pumps over several hours Conversely the work presented herein describes novel methods to synthesize adductfree alane It is demonstrated here that AlH3 can form by mixing AlCl3 and LiAlH4 in the solid state and heating to 75∘C only αAlH3 was obtained The αAlH3 product can be washed with minimal solvents leading to zero formation of alane adducts In addition the unwanted LiCl byproduct is also removed during the solvent wash resulting in halidefree αalane Although simply mixing and heating the reactants led to a 40 yield of alane having the reactants compacted and mechanically pressed while heating increases the yield to 60 crystalline αAlH3This work was supported by the LDRD program at Savannah River National Laboratory Our gratitude is extended to Dr Patrick O’Rourke from Analytical Development Directorate Savannah River National Laboratory for assistance in XRD analyses The authors acknowledge the facilities and scientific and technical assistance of the Australian Microscopy Microanalysis Research Facility at the Centre for Microscopy Characterisation Analysis The University of Western Australia a facility funded by the University State and Commonwealth Governments
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