The Reactions of Methyl Radicals. I. The Photolysis of Acetone

The photolysis of acetone has been investigated between 100°C and 300°C. The rates of production of carbon monoxide, methane and ethane have been measured over a range of acetone pressures from 3.9 to 100 mm and with a thirty-fold variation of light intensity. The methane and ethane formed can be quantitatively accounted for by the equations CH3+CH3=C2H6, CH3+CH3COCH3=CH4+CH2COCH3.It is found that E3—½E2=9.7 kcal., where E2 and E3 are the activation energies of the above reactions. The photolysis of deuterated acetone has also been investigated, here E3′—½E2′=10.3 kcal. The collision theory ``steric'' or ``P'' factor for the second reaction is less than 10−3 in each case.