Electrochemical Study of Diphenyl Ether Derivatives Used as Herbicides

Amira Zaouak,Fatma Matoussi,Mohamed Dachraoui

doi:10.4061/2011/904570

Abstract

The electrochemical behaviour of five nitro diphenyl ethers used as herbicides is investigated in acetonitrile. A detailed study by cyclic voltammetry and exhaustive electrolysis is carried out for the anodic oxidation of 2-Chloro-6-nitro-3-phenoxyaniline (aclonifen) and shows that the major oxidation product is a dimeric compound. A mechanistic scheme involving a coupling process is postulated for the electrochemical oxidation of this compound. Furthermore, the use of differential pulse voltammetry on a glassy carbon electrode permits the selective determination ofaclonifen. The limit of detection is 0.6 μg/mL.

Highlights

The nitro diphenyl ethers (NDPEs) are commonly used as herbicides
This paper reports the electrochemical behaviour of a series of p-nitro diphenyl ether derivatives: aclonifen, bifenox, acifluorfen, nitrofen, and 4-nitro diphenyl ether parent compound
A single reversible peak is obtained as observed in Figure 1, illustrating the reduction voltammogram of aclonifen. This is attributed to the formation of a stable anion radical at the concerned time scale

Summary

Introduction

The nitro diphenyl ethers (NDPEs) are commonly used as herbicides. The environmental contamination with these toxic molecules incited a number of studies concerning their occurrence and determination in various matrixes such as environmental waters and food by means of chromatography and related techniques [1–15]. The number of electrochemical studies concerning the NDPE derivatives are less numerous, even if the electrochemical approach is known to be effective both for analysis and destroying of various toxic compounds [16–20]. Scheme 1 presents the chemical structures of the selected molecules which are considered as multi-target herbicides. The nitro aromatic functional group is reducible with a characteristic cathodic wave. This has been observed in protic and aprotic media for bifenox and nitrofen [21, 22]. The anodic behaviour of aclonifen is analysed by means of differential pulse voltammetry (DPV), which is shown to be a sensitive method permitting a rapid determination of the concerned herbicides

Experimental

Voltammetric Study

Nitro DPE Acifluorfen

Conclusion