The Fe (III) compound, (2-) -o, o'-phosphonate iron (III) ethylphosphate, was prepared by the reaction of diethyl phosphonate with ferric nitrate in acetonitrile solvent at 100°C for 2 hour. The reaction of diethylphosphonate with ferric nitrate in water and acetonitrile solvent were studied, and the mechanism for the formation of Fe (III) compound was clarified.
Fe (III) compound reacted with 1-naphthol derivatives such as 5-amino-1-naphthol, 2-nitroso-1-naphthol and 4-chloro-1-naphthol, and salicylic acid to produce color (λmax = 510 nm-565 nm). The evaluation as spectrophotometric determination reagent of Fe (III) compound toward these aromatic compound was investigated. Beer's law was obeyed in a concentration range of 2-10 mg/l of 1-naphthol derivatives and salicylic acid. The determination of 5-amino-1-naphthol and salicylic acid were not interfered up to 100 times concentration of o, m, p-cresol, and the determination of 2-nitroso-1-naphthol and 4-chloro-1-naphthol were not interfered up to 100 times concentration of p-nitrophenol and 2-naphthol in their presence, respectively. It was found that this iron (III) compound could be sufficiently applied at the spectrophotometric determination of 1-naphthol derivatives and salicylic acid.
