INVESTIGATION OF LIQUID-METAL HYDRIDES

Studies of liquid beryllium hydride synthesis have resulted in a number of new species with theoretical specific impulses approaching 330 seconds and further defined the most promising classes of this type of high-energy fuel. In general, it appears that terminators derived from higher borane fragments e.g., B3-H7 are more advantageous than simple BH3 terminators. Liquids with B3H7 terminators exhibit high theoretical impulse and satisfactory fluidity, and unlike many BH3-terminated liquids, are not subject to reversible dissociation. The bulk of this investigation was concerned with the preparation of borane- terminated beryllium hydride BTBH liquids from the reaction of B4H10 with beryllium alkyls and alkylberyllium hydrides. The nature of the reaction products was dependent upon the experimental conditions. The use of B4H10 BeCH32 mole ratio of 0.5 and an extended reaction time yielded the best product, a liquid analyzing as B3H7CH3BeH2BeH2BH3 specific impulse, 329 seconds with H202. The use of B2H6B4H10 mixtures simplified the complex reactions involving pure B4H10 and solid beryllium compounds. Such mixtures increase the liquefaction rates of the beryllium compounds and also resulted in a significant decrease in the amount of B4H10 decomposition during its reactions. Ethyl-substituted BTBH liquids are synthesized. The compound B3H7- C2H5BeH BeH2BH3 specific impulse, 326 seconds remained fluid at -40C. Conditions for the quantitative reaction of AlCH33 and Beane were established for the preparation of alane-terminated beryllium hydride ATBH liquids.