NANOSCALE METAL-OXIDE PARTICLES CLUSTERS AS CHEMICAL REAGENTS - SYNTHESIS AND PROPERTIES OF ULTRAHIGH SURFACE-AREA MAGNESIUM-HYDROXIDE AND MAGNESIUM-OXIDE

A modified autoclave hypercritical drying procedure has been used to prepare a hydrated form of MgO from Mg(OCH3)2 in a methanol-toluene solvent mixture. This material was prepared with 1000 m2/g surface area and 35-angstrom crystallite size. Heat treatment of this precursor at 500-degrees-C under vacuum yielded the dehydrated MgO with 500 m2/g surface area and 45-angstrom crystallite size. The samples were further characterized by Fourier transform infrared/photoacoustic spectroscopy (FT-IR/PAS), X-ray diffraction, scanning electron microscopy, and chemical analyses. The hydrated precursor contained some residual -OCH3 groups and was much less crystalline in appearance than conventionally prepared MgO-Mg(OH)2 samples. The dehydrated material was free of -OCH3 groups and was made up of much smaller crystallites than conventionally prepared MgO.