Photochemical Studies in Flash Photolysis. II. Photolysis of Acetone with Filtered Light

Flash photolysis was studied in the absence of wavelengths below 200 mμ. Effects of acetone pressure, light intensity, added biacetyl, temperature, and wavelength were investigated. The results are consistent with primary acts postulated previously on the basis of low-intensity studies, but with the absence of complicating first-order secondary reactions at these high radical concentrations. Deactivation of excited molecules explains the pressure effect on the C2H6/CO ratio, for wall effects are absent under flash conditions. A hot radical mechanism is suggested by the data for methane formation. The effect of wavelength on C2H6/CO ratio in regions centered near 260, 280, and 295 mμ is rather striking, and the results are compared with trends in low-intensity studies in the same pressure region.