The C-F bond in perfluoroalkyl substances (PFAS) provides for a high degree of durability, which makes them desirable in a range of applications. Unfortunately, recent reclassification regarding the toxicity of PFAS substances has revealed that these compounds are far more toxic than was once believed, resulting in numerous explorations of different techniques for degrading these materials. In this talk, we discuss how our group applied density functional theory (DFT) in order to investigate how the carborane anion ([HCB11H5F6]−)/silylium (Et3SiH/Et3Si+) chemistry can be utilized for the degradation of PFAS. PFAS containing three fluorinated carbon atoms with various polar head groups (COOH, CHO, OH, and CH3) were explored to identify how the chemical structure impacts the defluorination mechanism. We find that the degradation process involves a Et3SiH/Et3Si+ pair acting in tandem, with the carborane anion forcing unoccupied anti-bonding orbitals to be partially occupied, which weakens the C–F bond. Swapping out the fluorines on the carborane to other halogens mediates this process, with iodic carborane ([HCB11H5I6]−) having the most beneficial effect. The results of this study provides atomistic insights into the defluorination mechanism of harmful PFAS using silylium catalysts

Silylium chemistry and PFAS: Providing atomistic insights into Hydrodefluorination

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.