Kinetic Study for Reactions of Nitrate Radical (NO3·) with Alcohols in Solutions

The rate constants for the reaction of nitrate radical (NO3·) with alcohols have been determined by flash photolysis method in aqueous and nonaqueous solutions. The reactivity of NO3· in acetonitrile was higher than that in aqueous solution, suggesting that hydrogen bonds between solvent and NO3· or alcohols decrease the reaction rate. From the deuterium-isotope effect, the main reaction path was confirmed to be hydrogen atom abstraction from the carbon atom bonded with the OH group. For 2-methyl-2-propanol, the hydrogen atom abstraction from the OH group was presumed. These reaction paths were confirmed, since the reaction rate constants decreased with an increase in the corresponding bond-dissociation energies. From strong dependency of the rate constants upon the ionization energies of alcohols, the polar transition states of the reactions were suggested.