Spectrophotometric study on the quaternary complex of titanium (IV) with secondary ligands, 2,6,7-trihydroxylphenyl-fluorone derivatives and cetyltrimethylammonium bromide

The new color reactions of titanium (IV) with six 2,6,7-trihydroxyl-9-phenylsubstituted-3-fluorone derivatives (THPF) have been studied in the presence of nitrilotriacetic acid (NTA) and cetyltrimethylammonium bromide (CTMAB). The effects of secondary ligands such as NTA, ascorbic acid, hydroxylamine and mandelic acid on the ternary complex of titanium (IV) have been reported. It was found that the system of titanium (IV)-2,6,7-trihydroxyl-9-(2,4-dichlorophenyl)-3-fluorone (DCPF)-NTA-CTMAB quaternary complex is the most sensitive in these systems studied. The apparent molar absorptivity of the complex at 576 nm is 1.9 × 10⁵ 1·mol^–1·cm^–1. The stoichiometric ratio of the Ti (IV)-NTA-DCPF-CTMAB complex is estimated to be 1 1 3 3. The proposed method proves to be satisfactory for the direct determination of titanium in alloy steels, silicate minerals and aluminium alloys. The method is highly sensitive and selective.