Theoretical investigation on atmospheric oxidation of fluorene initiated by OH radical

Atmospheric oxidation of fluorene and its derivatives initiated by OH radicalswas investigated theoreticallywith quantumchemical calculation methods [M06-2X/6-311++G(3df,2p)//M06-2X/6-311+G(d, p)]. It revealed that the OH addition pathways form hydroxyfluorene and ring-opening product dialdehyde while the H abstraction pathways lead to the formation of 9-fluorenone. Subsequent oxidation of 9-fluorenone has considerable potential to form dibenzo-p-dioxin and nitrofluorenone according to the present calculation results. The atmospheric lifetime of fluorene relative to the reactions with OH radicals is deduced to be 12.51 h based on the calculated overall rate constant (2.29 x 10(-11) cm(3) molecule(-1) s(-1)) at 298 K and 1 atm. The oxidation products of fluorene in the atmosphere are generally more toxic and persistent. This work provides a comprehensive explanation for atmospheric oxidation processes of fluorene and facilitates clarifying its environmental risks. (c) 2019 Published by Elsevier B.V.