IN-VITRO REDUCING ABILITIES TOWARDS CHROMATE OF VARIOUS HYDROXY-CONTAINING COMPOUNDS, INCLUDING SACCHARIDES AND THEIR DERIVATIVES

The reduction of potassium chromate has been carried out with a variet y of OH-containing compounds as reductants, which include pentoses, po lyols, glycols, and sugar derivatives. The corresponding reactions wer e followed using UV-vis and EPR spectroscopies and electrochemistry. T he progress of the chromate reduction reactions has been monitored by measuring UV-vis and EPR spectra as a function of time. The observed p seudo first-order reaction rate constants are derived based on the cha nges in the intensities of the Cr(VI), Cr(V), and Cr(III) signals. Cyc lic voltammograms of the simple reductants and their final Cr(III) pro ducts formed from the reactions of chromate have also been measured. T he reductive abilities of all these reductants have been derived from the spectral data and are discussed on a comparative basis. Based on t he results, the aspects that makes a particular reductant more efficie nt has been addressed. The results obtained from UV-vis, EPR, and cycl ic voltammetry are found to be mutually dependent and exhibit among th emselves a linear correlation, suggesting that both the reducing and c omplexing nature of these molecules play important roles in the chroma te reduction.