SILICON NMR-SPECTRA FROM THE REACTION SPECIES BETWEEN TETRAETHOXYSILANE AND CALCIUM NITRATE HYDRATE

NMR spectra were recorded of the silicon species obtained in the react ion between tetraethoxysilane and calcium nitrate hydrate in ethanol. The tetraethoxysilane reacted with a maximum of three of the four wate rs of hydration of the calcium nitrate at room temperature within a fe w days. The fourth water reacted after extended times (33 days) at roo m temperature or at enhanced temperature (60-degrees-C) within 24 hour s. Samples with less than sufficient water for a complete reaction sho wed the corresponding amount of unreacted tetraethoxysilane. The calci um nitrate stayed colloidally dispersed within the ethanol silica gel and remained so even after the ethanol was removed.