Sol-gel synthesis of hydrotalcite — like compounds

Sol-gel hydrotalcite-like compounds were prepared using two different magnesium precursors, on the one hand magnesium ethoxide and on the other magnesium acetylacetonate. The aluminum precursor was always aluminum acetylacetonate. The resulting interlayer anions were ethoxide–acetylacetonate and acetylacetonate, respectively. Instead of the conventionally accepted thermal autoclave treatment, a new gelling and crystallization method is proposed using microwave irradiation. The solids were characterized by X-ray diffraction, nitrogen physisorption, thermogravimetric analysis, infrared spectroscopy and transmission electron microscopy. It is found that the acetylacetonate precursors determine surface area and crystallinity. Microwave irradiation guarantees a high surface area for an irradiation time as low as 10 min.