title: Heterogeneous ozonolysis of folpet and dimethomorph: a kinetic and mechanistic study.
abstract: The research study discussed in this paper concerns determination of the kinetic rate constants for heterogeneous degradation of the pesticides folpet and dimethomorph by ozone at room temperature. The study also involves identification of the degradation products of the analyzed compound in the condensed phase by solid-phase microextraction/gas chromatography/mass spectrometry (SPME/GC/MS). The heterogeneous O3 reactivity of the identified degradation product of dimethomorph, 4-chlorophenyl 3,4-dimethoxyphenyl methanone (CPMPM), is also evaluated experimentally. The obtained results show that the rate constant values of the analytes are (1.7 ± 0.5) × 10(-19), (2.1 ± 0.8) × 10(-19), (2.6 ± 0.2) × 10(-20), and (2.7 ± 0.2) × 10(-20) cm(3)·molecule(-1)·s(-1) for (Z)-dimethomorph, (E)-dimethomorph, folpet, and CPMPM, respectively. Such values implicate heterogeneous ozone lifetimes that vary from a few days to several months, meaning that, depending on their reactivity with respect to other atmospheric oxidants, these compounds might be relatively persistent and may be transported to regions far from their point of application.
authors.affiliation: Groupe de Spectrométrie Moléculaire et Atmosphérique, Unité Mixte de Recherche CNRS 7331, and UFR Sciences Exactes et Naturelles Moulin de la Housse, Université de Reims Champagne Ardenne, B.P. 1039, 51687 Reims, France.
authors.forename: Mariam J
authors.initials: MJ
authors.lastname: Al Rashidi
authors.forename: Abdelkhaleq
authors.initials: A
authors.lastname: Chakir
authors.forename: Estelle
authors.initials: E
authors.lastname: Roth
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry; D007700:Kinetics; D015394:Molecular Structure; D009025:Morpholines / Q000737:chemistry* / Q000378:metabolism; D010126:Ozone / Q000737:chemistry*; D010575:Pesticides / Q000737:chemistry; D010797:Phthalimides / Q000737:chemistry* / Q000378:metabolism; D052617:Solid Phase Microextraction
chemical_list: D009025:Morpholines; D010575:Pesticides; D010797:Phthalimides; C076154:dimethomorph; D010126:Ozone; C005020:folpet