The defluorination of 4-trifluoromethoxybenzoic acid under environmentally relevant conditions

There is increasing interest over the widespread use of per- and polyfluoroalkyl substances (PFAS) due to their possible persistence and accumulation, leading to concerns over potential health and environmental impact. The worry stems back to compounds polytetrafluoroethylene (PTFE) and perfluorooctanoic acid (PFOA) discovered in the early 20th century. Recent definitions of PFAS have broadened the number of compounds included in this series, and due to the propensity of some of these compounds to accumulate they have been termed "forever chemicals". Herein, this study describes the defluorination of a molecule included in this definition, under environmentally relevant conditions. The degradation of [14C] 4-trifluoromethoxybenzoic acid labelled in the carbon of the OCF3 group was investigated in soil under aerobic conditions at a typical field application rate. The degradation rate was calculated from analysis of loss of parent compound over time, resulting in a degradation time of 50% (DegT50) range of 1.15-3.14 days, and the generation of 14CO2 between 61.8 and 72.7% of the total applied radioactivity. The results from this study show that OCF3 groups, and hence C-F bonds, can degrade under environmentally relevant conditions and on a short timescale.