Infrared laser photolysis of Freon 12

When the beam from a high power CO₂ laser operating at 10.6 μ impinges on a laminar stream of CF₂Cl₂ at NTP, it inflames and undergoes high conversion to CF₃Cl in an over‐all nearly thermally neutral reaction. Experiments demonstrating the appreciable nonthermal component of the reaction, based on a null‐hypothesis design, are reported. In a mixture of Freon 12/Ar/SF₆, the partial pressure of CF₂Cl₂ is held constant; the total flow rate (residence time) is constant; the absorption coefficient is changed by varying the amount of SF₆ in the (always optically thin) mixture; for each composition the laser power is changed until the average enthalpy increase of the Freon 12 component of the mixture would correspond to 24 kcal/mole (equilibrium temperature of [inverted lazy s] 1300°K); or the equivalent experiment is done by omitting SF₆ and changing the intensity by vertical expansion or compression of the beam. The rate is found to be stimulated about two orders of magnitude by the radiation and depends on the fifth power of laser intensity.