Kinetic isotope effect in hydrogen abstraction from 2-propanol by hydrogen and deuterium radicals. A pulse radiolysis Fourier transform electron spin resonance study

Using FT-ESR coupled with pulse radiolysis the kinetics of hydrogen abstraction from 2-propanol by hydrogen and deuterium radicals were studied in aqueous solution. The rate constants were determined from the effective spin–spin relaxation times of the free induction decay of hydrogen or deuterium ESR lines by variation of the 2-propanol concentration. The rate constants kHH and kDH for H (D)+2-propanol-h8 and kHD and kDD for H (D)+2-propanol-d7 show a kinetic isotope effect with kHH/kHD=8.2 and kDH/kDD=5.3. A secondary kinetic isotope effect is observed in the hydrogen (deuterium) abstraction from the C–H (C–D) bond by H or D radicals. These results are compared with ab initio quantum chemical data.