Review on High Valent Fe-VI (Ferrate): A Sustainable Green Oxidant in Organic Chemistry and Transformation of Pharmaceuticals

Iron is the most common metal by mass on earth and represents the basic element of industrial society. The usage of iron to synthesize consumer products and to remediate environment is an attractive approach. This perspective presents applications of the high-valent iron oxo compound (FeO42-)-O-VI (ferrate) in sustainable organic synthesis and treatment technology. In synthesizing organic molecules, C-H bond activation and selectivity are two basic ingredients of efficiency, which are attainable by ferrate. Examples of hydroxylation of hydrocarbons and conversion of alcohols to aldehyde/ketone are presented. In addition, many other organic molecules of amines, aniline, phenolic, and thiol functionalities can be oxidized by ferrate. This oxidation chemistry of ferrate is expedient in transforming pharmaceuticals, micropollutants in bodies of water with implications for human and ecological health. A wide range of micropollutants, which are commonly found in drinking water resources and wastewater effluents, can be efficiently oxidized by ferrate on a seconds to minutes time scale. These molecules include endocrine disruptors, antibiotics, beta-blockers, antidepressants, X-ray contrast media, and cosmetic products. The reaction pathways of transformation of the studied pharmaceuticals are discussed. The results of the evaluation of toxicity of the oxidized products are given. The reduced product of ferrate is the environmentally friendly and magnetic iron(III) oxide. Ferrate, as a green molecule, has true potential in sustainable production of organics and treating emerging pollutants in water.