Reactivity of chloroacetamides toward sulfide + black carbon: Insights from structural analogues and dynamic NMR spectroscopy

Chloroacetamides are commonly used in herbicide formulations, and their occurrence has been reported soils groundwater. However, how chemical structures affect transformation kinetics pathways the presence of environmental reagents such as hydrogen sulfide species black carbon not investigated. In this work, we assessed impact increasing Cl substituents on reaction six chloroacetamides. The contribution individual (reductive dechlorination vs. nucleophilic substitution) to overall decay selected chloroacetamides was differentiated using various experimental setups; both rates product distributions were characterized. Our results suggest that number affected kinetics: trichloroacetamides predominantly underwent reductive whereas mono- dichloroacetamides transformed via substitution. Furthermore, synthesized eight dichloroacetamide analogs (Cl2CHC(=O)NRR’) with differing R groups characterized kinetics. Dynamic NMR spectroscopy employed quantify rotational energy barriers dichloroacetamides. adsorption constrained from approaching dichloromethyl subsequently favored attack. This study provides new insights better predict fate subsurface environments by linking structural characteristics pathways.