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Synthesis of Nanocrystalline Iron Oxide Particles in the Iron(III) Acetate/Alcohol/Acetic Acid System
Author(s) -
Gotić Marijan,
Musić Svetozar
Publication year - 2008
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200700986
Subject(s) - chemistry , acetic acid , magnetite , hematite , inorganic chemistry , ethyl acetate , iron oxide , nuclear chemistry , alcohol , ethanol , organic chemistry , mineralogy , materials science , metallurgy
Nanosized iron oxide particles were synthesised without the addition of water by autoclaving iron(III) acetate/alcohol and iron(III) acetate/acetic acid/alcohol solutions at 180 °C for different time periods. Magnetite was formed in iron(III) acetate/ethanol, whereas hematite was formed in the iron(III) acetate/acetic acid/ethanol system. The average crystallite sizes of 11.1 and 22.6 nm and the stoichiometry of Fe 2.89 O 4 were found for the nanosized magnetite particles. The primary magnetite particles aggregated into regular spheres 5 to 10 μm in size, which can be explained by the specific character of the small, reactive and polar molecules of ethanol. In the iron(III) acetate/octanol system, a mixture of magnetite and hematite was obtained. The average crystallite size of magnetite was up to 22 nm and that of hematite was up to 46.7 nm. In the iron(III) acetate/acetic acid/ethanol system, nanosized hematite particles were exclusively formed. 13 C NMR spectroscopy revealed the presence of ethyl acetate ester in the supernatants. The formation of ester in the iron(III) acetate/ethanol system was explained by the catalytic oxidation of ethanol in the presence of acetate groups bonded to iron. Thus, in the oxidative dehydrogenation of ethanol into ethyl acetate, coordinated Fe 3+ served as an electron acceptor that was reduced to Fe 2+ , and exclusively magnetite was formed. With the addition of acetic acid to the iron(III) acetate/ethanol system, the free acetic acid directly participated in an esterification reaction with ethanol. Water molecules generated in situ in this esterification reaction hydrolysed iron(III) acetate, and thus hematite was formed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)