Quantitative Structure-activity Relationship: Prediction of Anaerobic Transformation of Chloroacetanilide Herbicides

Abstract

A preliminary analysis of quantitative structure-activity relationships was conducted over five selected chloroacetanilide herbicides: alachor, acetochlor, butachlor, metolachlor, and propachlor. Multiple structural, thermodynamic, atomic, electronic and steric descriptors were examined in regards to their correlations with nitrate-reducing rate constants and bisulfide reaction rate constants. Experimental results suggested there are various potential descriptors to predict the activity of these herbicides with bisulfide. Most notably, the descriptors carbonyl-carbon charge, Connolly excluded solvent volume, and molecular weight displayed the highest correlations for the bisulfide reaction. A limited number of descriptors were found to correlate well with the nitrate-reducing rate constants. Future areas of research might include further laboratory testing of descriptors, additional chloroacetanilides to examine, and testing to isolate denitrifying bacteria capable of degrading these herbicides.