Synthesis and Characterization of Precursors for Group II Metal Aluminates

Precursors to Group II metal aluminates (MAI2O4 , M=Mg, Ca, Ba, Sr) are synthesized from inexpensive starting materials including Group II metal oxides/hydroxides, Al(OH)3 , triethanolamine (TEA) and ethylene glycol, in a one-pot synthesis process. The precursors are soluble in common organic solvents and can be handled in moist air for a reasonable period of time. On pyrolysis in air to 1200 °C, all three precursors transform to the corresponding Group II metal aluminates. A termetallic double alkoxide, ‘ionomer-like’ structure is proposed, wherein the alkalineearth metal is encapsulated by a TEA molecule bridging two alumatrane units. The precursors were characterized using TGA, NMR, mass spectroscopy and elemental analyses, and the pyrolysed precursors were briefly characterized using x-ray diffraction analysis. © 1997 John Wiley & Sons, Ltd.