Before undertaking the experiments described below, we had attempted to follow the photobromination of butenes in liquid dichlorodifluoromethane (freon). As the thermal reaction was complete within a few minutes, even at-150, we substituted iodine monobromide, but the combined bromine still reacted rapidly. The resulting purple solution, stable in the dark, slowly became colorless when irradiated at-150'with a tungsten lamp.' ...
