Kinetics of the Oxidation of Tetrahydrofuran in Aqueous Solution Initiated by 2,2'-Azobis(2-amidinopropane) Dihydrochloride

The kinetics of tetrahydrofuran oxidation in aqueous solution initiated by 2,2'-azobis(2-amidinopropane) dihydrochloride were studied. The reaction rate was monitored by oxygen uptake using the manometric method. The initiation rate constant of water-soluble 2,2'-azobis(2-amidinopropane) dihydrochloride was determined within the range 303–323 K: log ki = (11.9 ± 0.6) – (104.8 ± 4.3)/θ [s–1], θ = 2.303RT kJ/mol. The rate of tetrahydrofuran oxidation (w) was found to depend linearly on its concentration. A quadratic dependence of w on the initiator concentration was observed. The values of k2(2k6)–0.5 (oxidation parameter) for tetrahydrofuran oxidation were obtained. In Arrhenius coordinates, this parameter is expressed as log (k2(2k6)–0.5) = (2.8 ± 0.1) – (36.1 ± 0.7)/θ [L0.5 mol–0.5 s–0.5], θ = 2.303RT kJ/mol. The rate constants for the reactions of tetrahydrofuran peroxyl radicals with α-tocopherol and with 2,2,5,7,8-pentamethyl-6-chromanol in aqueous medium were determined as (2.0 ± 0.3) × 105 L mol–1 s–1 (303–318 K) and (2.8 ± 0.5) × 105 L mol–1 s–1 (309 K), respectively.