Mechanochemical synthesis of alane

Alane can be synthesized by cryomilling alanate and aluminium halides. The yield of alane has been found to be increased using 3NaAlH(4) + AlCl(3) and 3LiAlD(4) + AlBr(3) compared to 3LiAlD(4) + AlCl(3). Furthermore the relative amount of alpha'- over alpha-alane has increased from 0.63-0.67 to 1.05 by adding small amounts of FeF(3) to 3LiAlD(4) + AlCl(3). When synthesized from 3NaAl(H)4 + AlCl(3) the ratio alpha'/alpha was also increased to 1.04. alpha'-AlH(3) was confirmed to be less thermally stable than alpha-AlH(3). The maximum amount of synthesized alane was obtained by using NaAlH(4) as a starting material instead of Li-alanate. However, the synthesis route from NaAlH(4) provided alane with less thermal stability than the synthesis from LiAlD(4). The use of Na(3)AlH(6), LiH or TiCl(3) resulted in no alane formation. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.