Oxidation of 3-(4-methoxyphenoxy)-1,2-propanediol (MPPD) by bis(hydrogenperiodato) argentate(III) complex anion, [Ag(HIO₆)₂]⁵⁻ has been studied in aqueous alkaline medium by use of conventional spectrophotometry. The major oxidation product of MPPD has been identified as 3-(4-methoxyphenoxy)-2-ketone-1-propanol by mass spectrometry. The reaction shows overall second-order kinetics, being first-order in both [Ag(III)] and [MPPD]. The effects of [OH⁻] and periodate concentration on the observed second-order rate constants k′ have been analyzed, and accordingly an empirical expression has been deduced:

k¢ = ( k\texta + k\textb [ \textOH - ] )K 1 \mathord

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\vphantom k¢ = ( k\texta + k\textb [ \textOH - ] )K 1 { \textf( [ \textOH - ] )[ \textIO 4 - ]\texttot + K 1 } { \textf( [ \textOH - ] )[ \textIO 4 - ]\texttot + K 1 }, {{k^{\prime} = \left( {k_{\text{a}} + k_{\text{b}} \left[ {{\text{OH}}^{ - } } \right]} \right)K_{ 1} } \mathord{\left/ {\vphantom {{k^{\prime} = \left( {k_{\text{a}} + k_{\text{b}} \left[ {{\text{OH}}^{ - } } \right]} \right)K_{ 1} } {\left\{ {{\text{f}}\left( {\left[ {{\text{OH}}^{ - } } \right]} \right)\left[ {{\text{IO}}_{ 4}^{ - } } \right]_{\text{tot}} + K_{ 1} } \right\}}}} \right. \kern-\nulldelimiterspace} {\left\{ {{\text{f}}\left( {\left[ {{\text{OH}}^{ - } } \right]} \right)\left[ {{\text{IO}}_{ 4}^{ - } } \right]_{\text{tot}}\, +\, K_{ 1} } \right\}}},

where [IO₄ ⁻]_tot denotes the total concentration of periodate and k _a = (0.19 ± 0.04) M⁻¹ s⁻¹, k _b = (10.5 ± 0.3) M⁻² s⁻¹, and K ₁ = (5.0 ± 0.8) × 10⁻⁴ M at 25.0 °C and ionic strength of 0.30 M. Activation parameters associated with k _a and k _b have been calculated. A mechanism is proposed, involving two pre-equilibria, leading to formation of a periodato–Ag(III)–MPPD complex. In the subsequent rate-determining steps, this complex undergoes inner-sphere electron-transfer from the coordinated MPPD molecule to the metal center by two paths: one path is independent of OH⁻, while the other is facilitated by a hydroxide ion.