Degradation of Diethyl Phthalate by HO^• and SO₄^• – in the Aqueous Phase: Mechanisms, Kinetics, and Toxicity

Abstract

The chemical degradation processes of diethyl phthalate (DEP) induced by HO • and SO 4• − in aqueous solution were studied in a theoretical way. Not only radical addition and H-abstraction reactions but also singleelectron transfer processes of DEP were considered. The thermodynamic and kinetic results indicate that the more favorable pathways are the H abstraction occurring in aliphatic side chains for all HO • /SO 4• − -initiated degradation reactions of DEP. Subsequent reaction mechanisms of crucial primary intermediates were taken into account. At 298 K, the total rate constants for DEP degradation reactions induced by HO • and SO 4• − are 2.34 × 10 9 and 1.24 × 10 8 M −1 s −1 , respectively. They are in accordance with the experimental data. In comparison to SO 4• − , HO • has higher reactivity toward DEP in the research temperature range of 273−303 K. Considering the impact on the water ecoenvironment and human health, DEP and its 10 products have no bioaccumulation potential, but most products are developmentally toxic, except for (Z)-ethyl-2,5-dioxopent-3-enoate. Moreover, (Z)-ethyl-2,5-dioxopent-3-enoate is acutely toxic to fish; phthalic acid is mutagenicity positive; and we should pay more attention to them in the future.

Atmospheric Degradation of 3-Methoxy-1-propanol by Reaction with Hydroxyl Radicals and Chlorine Atoms

“…The electronic partition function of the Cl• atoms was evaluated by considering the splitting of 881 cm –1 between the ground 2 P 3/2 and excited 2 P 1/2 electronic states of Cl• atoms . The CTST method developed by Singleton and Cvetanovic and Alvarez-Idaboy et al , has been successfully employed to a lot of similar reaction systems. − …”