PULSE RADIOLYSIS OF 2,4,5-TRICHLOROPHENOL: FORMATION, KINETICS, AND PROPERTIES OF HYDROXYTRICHLOROCYCLOHEXADIENYL, TRICHLOROPHENOXYL, AND DIHYDROXYTRICHLOROCYCLOHEXADIENYL RADICALS

Article abstract of DOI:10.1021/j100342a048

Pulse radiolysis has been used to optically and kinetically characterize the transient free radicals formed by the reaction of H^., N3^., or OH^. with 2,4,5-trichlorophenol (TCP-OH).The hydroxy-2,4,5-trichlorocyclohexadienyl radical (H-TCP-OH) formed by H^. addition to TCP-OH -1s^-1> has an absorption maximum at 360 nm with ε₃₆₀=(4700+/-1000) M^-1cm^-1.The 2,4,5-trichlorophenoxyl radical (TCP-O^.) formed by the reaction of N3^. with TCP-O^- -1s^-1> has an absorption maximum at 430 nm with ε₄₃₀=(3600+/-600) M^-1cm^-1.The dihydroxy-2,4,5-trichlorocyclohexadienyl radical (HO-TCP-OH) formed by OH^. radical addition to TCP-OH -1s^-1A has an absorption maximum at 320 nm with ε₃₂₀=(5300+/-250) M^-1cm^-1.The principal isomer formed by the reaction of OH^. with TCP-OH is the 1,6-dihydroxy-2,4,5-trichlorocyclohexadienyl radical, which has a pK_a of 4.8+/-1.0.The solution absorption from each radical decays via second-order kinetics on the millisecond time scale.