Stoichiometry and Reactive Products

Since the kinetics in these redox sterns seem to be rather complex, owing to the formation of either unstable Cr (V) or Cr (IV) transient species through the reduction of chromium ion oxidant from hexavalent state to the trivalent ones, determination of the stoichiometiy becomes very important. 

These products were defined as poly(vinyl ketone], diketo-derivatives for methyl cellulose and carboxymethyl cellulose or diketoacid derivatives of carrageenans and chondroitin-4-sulfate, respectively. The oxidation products were isolated and identified by the spectral data and elemental analysis, respectively [98-100]. The keto-derivatives showed broad IR absorption bands at 1730-1760 (broad] cm that characterize the carbonyl groups of ketones. The enhancement of the absorption bands of OH groups in the IR spectra may indicate the complete oxidation of the OH groups to its corresponding keto-derivatives [101]. The products were also confirmed by the reactions with 2,4-dinitrophenyl hydrazine and hydroxylamine to afford the corresponding 2,4-dinitrophenyl hydrazone and oxime derivatives, respectively [67-71]. 

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