Comportarea polarografica a titanului (VI) in prezenta acidului citric

Ti(IV) forms 1:1 complexes with citric acid in solutions containing 0.2M H2SO4. Polarog. Ti(III) was formed by reduction of the complex at the 1st kinetic wave, with halfwave potential -0.37 V, and subsequent irreversible reduction of the free Ti(IV) ions at the 2nd wave, with halfwave potential of -0.84 V. At high citric acid concentrations, the rate-determining step of the electrode processes is the diffusion of Ti. Ti(IV) is probably coordinated to adjacent CO2- groups. The product between rate constant and the stability constant of the complex, determined by the J. Koutecky (1953) equation, is 24.5 s-1 at 21°.