A Kinetic Study of the Oxidation of Ti(III) to Ti(IV) in Hydrofluoric Acid Solutions

The oxidation of Ti(III) to Ti(IV) has been studied in hydrofluoric acid at temperatures of 25 °, 34.5 °, and 41.5 °C. The initial Ti(III) concentration was varied from 0.05 to 0.5 M and the initial HF concentration from 0.25 to 2.0 M. In solutions with moderate HF Ti(III) ratios, reaction rate orders of approximately unity were found for both Ti(III) and HF. There were also indications that the various Ti(III)-fluoride complexes were oxidized at different rates. The low apparent activation energy ( 6 kcal) was an indication of a rate determining step between ions of similar sign. © 1968