diethylhydridoaluminium

Production Methods

The ether complex of diethylaluminum chloride is prepared first by adding dropwise one-half mole of AlCl3, dissolved in some ether, to one mole of Al(C2H5) 3·O(C2H5)2. When the evolution of heat ceases, the excess solvent is evaporated, and the Al(C2H5)2Cl etherate is distilled in a vacuum. A 76 -g portion of this product is diluted with 120 ml of absolute ether and placed in a 500-ml, three-neck flask, which has been flushed with dry nitrogen. A suspension of LiH in ether (62 ml, 7 M in LiH) is prepared in a dropping funnel under a nitrogen blanket and allowed to flow into the flask. Lithium chloride separates, and the reaction mixture boils. Toward the end of the reaction, stirring is applied, and the mixture is heated to 40°C for 15 minutes. The LiCl rapidly precipitates when the flask is allowed to cool. The precipitate is washed with a small volume of ether, which is then evaporated in an aspirator vacuum, the last traces being removed at 50°C. The residual Al(C3Hs)aH is distilled in a high vacuum, holding the flask in a bath maintained at 80°C or lower. It is collected in a receiver cooled to - 20°C.