SYNTHESIS AND CHARACTERIZATION OF IRON STEARATE COMPOUNDS

A derivative of a known trinuclear iron(III) stearate cluster was prep ared from ferrous sulfate and sodium stearate in ethanol/water solvent with air oxidation. It was also prepared by increasing the pH of a so lution of ferrous sulfate stirred with stearic acid. The formula for t he trimer as prepared here is [Fe3O(St)(6)(H2O)(3)](+)St(-)(St(-) = st earate, n-C17H35CO2-). The reaction of ferric citrate with stearate to form the trimer does not go to completion. The true: composition of m ost iron stearates has not been well established previously. Two iron stearate compounds are available commercially; of these, only ''ferrou s stearate'' appears to be a pure compound, albeit not a simple mononu clear one. The ''ferric stearate'' of commerce appears to be a mixture of stearic acid and a compound similar to the iron trimer prepared he re. References exist to ''iron distearate hydroxide'' in the literatur e. The physical and spectroscopic properties of this compound are very similar to those of the iron trimer prepared here. Spectral data (mid - and far-IR, 300 MHz H-1 and 75 MHz C-13 NMR) and TGA/DSC data are re ported for stearic acid, ''ferrous stearate,'' ''ferric stearate,'' an d [Fe3O(St)(6)(H2O)(3)][St].