Kinetics of Hexafluoropropylene Oxide Pyrolysis Studied by Gas‐Phase NMR. Kinetic Measurements Made Easy

Gas‐phase NMR complemented with a high‐temperature probe makes possible quantitative kinetic studies of homogeneous vapor‐phase reactions with unprecedented ease, as demonstrated with a study of the thermal fragmentation of hexafluoropropylene oxide. The reaction follows strictly first‐order kinetics, is unaffected by surface chemistry, and the resulting Arrhenius activation parameters compare well with those obtained by more laborious classical methods of gas‐phase reaction kinetics. The fragmentation kinetics is also unaffected by the presence of oxygen. The profiles for the evolution of the final products in this case show very graphically that singlet difluorocarbene, one of the initial products of the fragmentation of hexafluoropropylene oxide, does not react with oxygen, a ground‐state triplet, at chemically significant rates.