Processable aluminosilicate alkoxide precursors from metal oxides and hydroxides. The oxide one-pot synthesis process

An inexpensive and facile way to make processable aluminosilicate precursors has been developed. In this process, the ‘oxide one-pot synthesis process’, mixtures of SiO2, Al(OH)3 and a group I/II hydroxide/oxide, in any stoichiometric ratio, are reacted with one mole of triethanolamine (TEAH3) per mol of metal, by heating in ethylene glycol (EGH2) such that the byproduct H2O distills off. Solvent removal provides relatively moisture- and air-stable, viscous, polymer-like precursors that probably consist of silatrane (TEASi-EGH) and alumatrane [(TEAAl)4] complexes. Spinel, mullite and cordierite precursor syntheses are described. The mullite and cordierite precursors most probably are homogeneous mixtures of single-metal alkoxides rather than atomically mixed, bi- and tri-metallic alkoxides. The precursors are soluble in common solvents, and offer viscoelastic properties suitable for powder, coating and fibre spinning applications. Pyrolysis (in air) to 700 °C provides glass or ceramic materials with exactly the stoichiometry of the starting oxide mixture.