A simple chemical route for the synthesis of γ-Fe2O3 nano-particles dispersed in organic solvents via an iron–hydroxy oleate precursor

A simple chemical route is developed to generate maghemite (γ-Fe2O3) nano-particles, dispersed in organic solvents via a thermal decomposition of an iron–hydroxy oleate precursor. An iron–hydroxy oleate precursor was generated by chemical reaction of mixed iron nitrate and oleic acid in ethanol with 30% NH3 solution with continuous stirring at room temperature. The precursor thus obtained was suspended in hexadecane and then mixed with necessary quantity of oleic acid at room temperature with constant stirring and is further heated to 220 °C/2 h to convert it in to γ-Fe2O3 nano-particles. The mixture is allowed to cool slowly to room temperature. The γ-Fe2O3 nano-particles remained in dispersed state in hexadecane. The iron–hydroxy oleate molecular precursor and γ-Fe2O3 nano-particles are characterized using various physico-chemical characterization techniques like DTA/TGA, IR, XRD, vibrating sample magnetometer (VSM), TEM, and EDAX. The characterization results indicated that γ-Fe2O3 nano-particles (size 6–15 nm) are obtained by a thermal decomposition of an iron–hydroxy oleate precursor and possess spherical shape. These particles remained dispersed state in organic solvent due to capping action of oleate molecules. The results are quite reproducible and γ-Fe2O3 nano-particles can also be dispersed in another organic solvents like kerosene, 2-methyl naphthalene etc.