2-Hydroxy-4-Ethoxy Valerophenone Oxime as an Analytical Reagent for Molybdenum(VI)

Abstract

Molybdenum(VI) forms yellow coloured stable complex with 2-hydroxy-4-ethoxy valerophenone oxime at pH 3.0 in 50% aqueous ethanol medium. The complex absorbs maximum at 420 nm. The composition of the complex determined by Job's method was found to be 1 : 1 (metal : ligand). The stability constant of the complex is found to be 1.102 x 10⁵. The standard free energy change for the formation of the complex is -6.98 kcal/mol at 30ºC. Beer's law is obeyed up to 120.96 ppm of Mo(VI) ion. The molar absorptivity and Sandell's sensitivity at 420 nm are found to be 1.51 x 10² L/mol cm and 0.635 μg/cm², respectively. Interference due to presence of foreign ions in the spectrophotometric determination of Mo(VI) has been studied. The reagent has also been found to be give quite satisfactory results for the determination of molybdenum in ferro-molybdenum.