Citric acid oxidation by vanadium(V) in sulfuric acid medium: Kinetic and mechanistic study

The citric acid oxidation by vanadium(V) in sulfuric acid medium at 303 K i s reported The reaction rate was determined spectrophotometrically by monit oring the formation of vanadium(IV) at 760 nm. The oxidation showed a First -order dependence with respect to vanadium(V) concentration and fractional order with respect to citric acid concentrations, with no control and with constant ionic strength. The reaction is also First order with respect to s ulfuric acid concentration with no control and of fractional order at const ant ionic strength. The reaction rate is enhanced by an increase of ionic s trength and increased by a decrease of the dielectric constant. The activat ion parameters were calculated based on the rate constants determined in th e 293 to 313 K interval. The proposed oxidation mechanisms and the derived rate laws are consistent with the experimental rate laws. (C) 2000 John Wil ey & Sons, Inc.