an apparatus and a method for controllably converting aluminum into alane . in the system of the invention , a reaction between aluminum and hydrogen to form alane is performed at temperatures below 100 ° c . using a supercritical fluid such as co 2 as a reaction medium , with the optional inclusion of a co - solvent , such as an ether , in the reaction vessel . inert gas is used to exclude unwanted gases such as oxygen . the reaction of aluminum and hydrogen has been observed to proceed at approximately 60 ° c . using me 2 o as an added solvent in co 2 at supercritical pressures .