AN INVESTIGATION OF DIRECT SYNTHESIS OF GROUP IA HEXAHYDRIDOALUMINATES

An evaluation of the direct synthesis of the hexahydridoaluminates (M2AlH4) of lithium, sodium, and potassium from the alkali metals, aluminum, and hydrogen is presented in this report. Although Na3AlH6 and K3AlH5 can be readily prepared from the elements, no satisfactory conditions for the direct synthesis of Li3AlH6 were found. Evidence is presented which indicates that the direct synthesis of K3AlH6 is an equilibrium process and that a similar equilibrium may acount for some reactions of Na3AlH6 in THF. K3AlH6, although insoluble in the common organic solvents, was shown to reduce benzophenone to benzhydrol and tri-n-butyltin chloride to the corresponding hydride. Attempts to prepare Mg3(AlH6)2 by the reaction of Na3Al 6Hand magnesium chloride were not successful. © 1969, American Chemical Society. All rights reserved.