SELECTING ETHANOL AS A MODEL ORGANIC-SOLVENT IN RADIATION-CHEMISTRY .2. GAMMA-RADIOLYSIS AND PULSE-RADIOLYSIS OF THE ACETOPHENONE-ETHANOL SYSTEM

Both gamma and pulse radiolysis of acetophenone in ethanol solutions h ave been studied. The dependence of G Values of hydrogen, 2,3-butanedi ol and acetaldehyde on acetophenone concentration was examined. Four n ew gamma radiolytic products of acetophenone (P1, P2, P3 and P4) were detected. The material balance between e(s)(-) and the ensuing product s was achieved. The ratio of rate constants k(e(s)(-)+C6H5COCH3)/k(e(s )(-)+CH3CHO) was simulated by computer to be 5. Upon pulse radiolysis of acetophenone in Ar-saturated ethanol solutions, a C6H5CO-CH3 radica l anion was formed with absorption peaks at 315 and 440 nm, which were assigned to the electron transition of pi-pi and n-pi* respectively, and the ratio of epsilon(315)/epsilon(440) was calculated to be 7.2. The molar extinction coefficient of acetophenone radical anion at 440 nm was determined to be 3847 mol(-1) dm(3)/cm and the absolute rate co nstant for the decay of acetophenone radical anion about 8 x 10(10) mo l(-1) dm(3)/s was obtained. Copyright (C) 1996 Elsevier Science Ltd.