STUDIES ON ENTHALPIES OF CARBON-OXYGEN BO ND-CLEAVAGE IN RADICAL IONS.2. BOND-ENERGIES OF RADICAL-ANIONS

Three series of fossil model compounds were synthesized and their oxid ation and reduction potentials were determined by CV using BAS-100B el ectrochemical analyzer, Thermodynamic cycles have been developed to de termine the enthalpies of the carbon-oxygen bond cleavage of the deriv ed radical ions, It was found that the carbon-oxygen bond is similarly activated in a thermodynamic sense by introducing an electron to the system as what was observed previously in a structurally similar radic al cation, except smaller in amplitude, The carbon-oxygen bond cleavag es of radical ions are all exothermic or slightly endothermic, implyin g a low barrier for rupture of the sessile bond, This is important to fossil fuel industry for improving traditional coal gasification routi ne and selecting new fragmentation path, Correlation analysis shows th at plots of Delta H-cleav[C-O](.+) vs. (Delta BDE - Delta E(ox) [C-O]) and Delta H-cleav[C-O](.-) vs. (Delta E(red)[C-O]+Delta pK(a)[HA]) ar e linear. Bond properties in relation to their structural features for both radical ions and their parent molecules are discussed and are co mpared with the relevant bond energy data in literature.