Kinetic and Analytical Studies of Oxidation of Cellulose Acetate and Cotton Linters with Ammonium Hexanitratocerate (IV)

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">The kinetics of oxidation of cellulose acetate was extensively studied to evaluate the thermodynamic parameters and the formation constant (<i>K</i>_f) of the intermediate complex and to work out the optimal conditions for analytical determination of cellulose content in cellulose acetate and cotton linter varieties/hybrids through an established stoichiometry. Second order rate constants obtained in these investigations were used to correlate the effects of variation of [CA], [Ce(IV)], [H⁺], ^aNO<img src='/image/spc_char/3_bar.gif' border=0> and added [Ce(III)]. The mechanism of oxidation of cellulose involved the formation of a transitory cyclic complex, followed by disproportionation of the complex. The disproportionation of the intermediate complex is the rate-determining step. The values for <i>K</i>_f, Δ <i>E</i>^{<img src='/image/spc_char/unequal.gif' border=0>}, - Δ <i>H</i>^{<img src='/image/spc_char/unequal.gif' border=0>}, Δ <i>F</i><img src='/image/spc_char/unequal.gif' border=0>, Δ <i>S</i>^{<img src='/image/spc_char/unequal.gif' border=0>} and log A were found to be 2.81 x 10² l mol^-1, 16.11, 16.52, 3.45 kcal mol^-1, -42.44 eu and 9.37 respectively. A series of analytical estimations of cellulose content in these polymeric materials were undertaken using the optimal conditions and stoichiometry of oxidation of cellulose.</span>