Mercury-Photosensitized Oxidation of Tetrafluoroethylene

Abstract

The mercury‐photosensitized reactions of C₂F₄ were studied in the absence and the presence of oxygen at room temperature. In the absence of oxygen, the only product was cyclo‐C₃F₆, whereas CF₂O and another unidentified product were also formed in the presence of oxygen. The cyclo‐C₃F₆ formation rate was unaffected by oxygen or nitrogen and was proportional to the C₂F₄ pressure and the square root of the incident intensity. The results are explained. The oxidation apparently does not involve the CF₂ radical. Two processes are introduced to explain the oxygenated products. One of these is attack of C₂F₄ by oxygen atoms produced from the mercury‐photosensitized decomposition of oxygen. The other involves the reaction of molecular oxygen with an electronically excited C₂F₄ molecule. The first oxidation process can be suppressed by the addition of nitrogen, whereas the second cannot. The oxidation mechanism presented is not complete but does explain the major trends.