Insight into the Mechanism of the OH-Induced Reaction of Ketoprofen: A Combined DFT Simulation and Experimental Study

The OH-induced reactions are the most important reactions for the degradation of pharmaceutical and personal care proucts (PPCPs) in advanced oxidation process (AOP) systems. In this work, the transformation mechanisms of a typical PPCP, ketprofen (KP), are investigated in detail by combined density functional theory (DFT) simulations and laboratory experiments. We find that Habstraction pathways are preferred in the OH-initiated reactions, and the influence of the hydrogen bond between the OH radical and the carboxyl group cannot be neglected. The subsequent decarboxylation and decomposition reactions are likely to occur. In addition, under highly acidic condition, the protonation of the carbonyl group in KP or in other benzophenone-like compounds might inhibit the decomposition reactions. Meanwhile, the simulation results are well supported by the Fenton experiments.