Benzene (C₆H₆), as an inner-standard substance, was added into C₁₂H₁₀O-HNO₂ system, which would form competition reaction between C₁₂H₁₀O and benzene with •OH radical. We analyzed decay kinetic curve in C₁₂H₁₀O-C₆H₆-HNO₂ system under 355 nm laser flash photolysis, on the basis of which, formation rate constant of C₁₂H₁₀O-OH adduct was obtained by combining its decay rate constant. By means of one kind of approximate method—perturbation theory, formation rate constant of C₁₂H₁₀O-OH adduct was concluded to (1.8±0.8)×10¹⁰ L•mol^－1•s^－1 by fitting decay curve at ＞340 nm.

Key words: laser flash photolysis, C₁₂H₁₀O-OH adduct, perturbation theory, formation rate constant