Association Kinetics for Perfluorinated -Alkyl Radicals.

Radical-radical reaction channels are important in the pyrolysis and oxidation chemistry of perfluoroalkyl substances (PFAS). In particular, unimolecular dissociation reactions within unbranched -perfluoroalkyl chains, and their corresponding reverse barrierless association reactions, are expected to be significant contributors to the gas-phase thermal decomposition of families of species such as perfluorinated carboxylic acids and perfluorinated sulfonic acids. Unfortunately, experimental data for these reactions are scarce and uncertain.

Thermochemistry of Gas-Phase Thermal Oxidation of C to C Perfluorinated Sulfonic Acids with Extrapolation to C.

New ideal-gas thermochemistry (), °(), °(), and °() are predicted for 53 species involved in the thermal destruction of perfluorinated sulfonic acids (PFSAs) ranging from C to C in perfluorinated alkyl chain length. Species were selected by considering both the pyrolytic and oxidative pathways of PFSA destruction. After the sulfur-containing moieties are removed, subsequent reactions largely involve species from a prior set of thermochemistry for the thermal destruction of perfluorinated carboxylic acids (Ram et al.

Thermochemistry of Species in Gas-Phase Thermal Oxidation of C to C Perfluorinated Carboxylic Acids.

New thermochemical properties, (), °(), °(), and °(), are predicted for 123 species involved in the thermal destruction of perfluorinated carboxylic acids (PFCAs) using computational quantum chemistry and ideal-gas statistical mechanics. Relevant species were identified from the development of mechanisms for the pyrolysis and oxidation of PFCAs of C to C in length. Partition functions were obtained from the results of calculations at the G4 level for species up to C in length and M06-2X-D3(0)/def2-QZVPP for species C to C in length.