Extraction and spectrophotometric determination of titanium(IV) with N-phenyllaurohydroxamic acid and phenylflurone

Abstract

N-Phenyllaurohydroxamic acid reacts with titanium(IV) in 9–10 M hydrochloric acid to give a complex that is completely extractable into solvents such as hexane and chloroform. The chloroform extract of the titanium complex, on second extraction from a dilute hydrochloric acid medium (0.1–0.5 M), in the presence of phenylfluorone and isoamyl alcohol, forms an intensely coloured complex possessing an absorption maximum at 540 nm. Even though the molar absorptivity of the complex under optimum conditions at 540 nm is 2.33 × 10⁵ l mol^–1 cm^–1, the measurements are more precise at 560 nm with a molar absorptivity of 1.23 × 10⁵ l mol^–1 cm^–1. The system obeys Beer's law for up to 0.4 p.p.m. of titanium (IV). Considerable amounts of many cations and anions including a 350-fold molar excess of iron(III) can be tolerated. Interference from zirconium(IV) can be mitigated or even eliminated by the addition of fluoride ions. The method can be applied to the determination of titanium present at 10 parts per 10⁹.