Oxidation of thioacetamide by ferrate(VI)

The rates of thioacetamide oxidation with ferrate(VI) (Fe(VI)) were determi ned as a function of pH (9.14-12.00) and temperature (15-35 degrees C) in 0 .01 M phosphate. The reaction was found to be first order for each reactant . The activation energy, Delta E-not equal, obtained was 59.7 +/- 0.7 kJ mo l(-1). The rates decrease with an increase in pH. The stoichiometry determi ned was 8HFeO(4)(-)+ 3CH(3)CSNH(2) + 9H(2)O --> 8Fe(OH)(3) + 3CH(3)CONH(2), + 3SO(4)(2-)+ 2OH(-). A mechanism is proposed in which thioacetamide is ox idized by Fe(VI) in steps to sulfenyl, sulfinic, and sulfonic acid and fina lly to sulfate and acetamide. The comparison of results with other sulfur-c ontaining compounds suggests that compounds undergo oxidation at S(-2) site by Fe(VI). (C) 2000 Elsevier Science B.V. All rights reserved.