ALUMINUM SEC-BUTOXIDE MODIFIED WITH ETHYLACETOACETATE - AN ATTRACTIVE PRECURSOR FOR THE SOL-GEL SYNTHESIS OF CERAMICS

Aluminum sec-butoxide can be modified by chelating ligands such as ethylacetoacetate (etac). Al(OBus)2(etac) was characterized by IR, 27Al, 13C and 1H NMR: several oligomeric species containing 4, 5 or 6 coordinated Al atoms could be present. During hydrolysis, butoxy groups are rapidly removed, but the presence of less hydrolyzable ligands slows down the reactivity of the precursor towards water. Precipitation can be avoided. Thus, this precursor appears quite attractive for the preparation of multicomponent ceramics such as α-cordierite. Modified aluminum alkoxide, tetraethoxysilane and magnesium acetate were used to obtain monolithic gels that convert into α-cordierite at 1000°C. The conversion processes, from the solution to the gel and the ceramics, were followed by 27Al and 29Si NMR in both liquid and solid states. © 1990.