PREPARATION OF HECTORITE CLAYS UTILIZING ORGANIC AND ORGANOMETALLIC COMPLEXES DURING HYDROTHERMAL CRYSTALLIZATION

A method for incorporating a remarkably diverse variety of intercalants directly during hydrothermal synthesis of hectorite layer-silicate clays has been developed. Refluxing a gel of silica sol, magnesium hydroxide sol, and lithium fluoride for just 2 days in the presence of an organic or organometallic intercalant results in crystalline products containing either (a) organic dye molecules such as ethyl violet and methyl green, (b) dye molecules such as alcian blue that are based on a Cu(II) phthalocyanine complex, or (c) transition metal complexes such as Ru(II) phenanthroline and Co(III) sepulchrate. The following properties of any intercalant are found to be necessary. (i) water solubility, (ii) positive charge, and (iii) thermal stability under moderately basic (pH 9-10) aqueous reflux conditions. The materials, and ion-exchanged natural hectorites for comparison, are characterized by X-ray powder diffraction, N2 BET surface area measurements, microanalysis, and thermal gravimetric analysis.