Rate coefficients for the reactions of hydroxyl radicals with a series of cyclic ethers and aliphatic diethers have been determined at 298 ± 2 K. Experiments were performed using a photolytic relative rate method at atmospheric pressure and the absolute rate technique of pulsed laser photolysis−laser induced fluorescence. The temperature dependence of the rate coefficients for the cyclic ethers was also studied over the temperature range 263−372 K. The rate coefficients show significant deviations from simple structure−activity relationships. The reactivity of the aliphatic diethers toward hydroxyl radicals is discussed in terms of the initial formation of a hydrogen-bonded adduct which then undergoes an intramolecular H atom transfer via five-, six-, and seven-membered-ring structures. The reactivity of cyclic ethers is also discussed in relation to adduct formation. However, because of steric restrictions, it is unlikely that the hydrogen-bonded adducts readily undergo H atom transfer via ring formation.

In Table 1, the reference compound used for 1,3dioxepane was in fact (CH 3 ) 2 CHOCH 2 CH 2 OH and not (CH 3 ) 2 -CH(OH)CH 2 OCH 3 . The rate coefficient for reaction of OH with (CH 3 ) 2 CHOCH 2 CH 2 OH (k 5 ) was 21.0 × 10 -12 cm 3 molecule -1 s -1 , as reported by Porter et al. 2 The reported value of k 4 /k 5 for 1,3-dioxepane, 0.58