Hydrogen abstraction from poly(propylene) and poly(propylene oxide) by hydroxyl radicals: a computational quantum semi-empirical study

The reaction of hydrogen abstraction by hydroxyl radicals on two substrates (poly(propylene) and poly(propylene oxide)) was studied using three quantu m semi-empirical methods (MNDO, AMI, PM3). The calculations were performed as a function of the site of abstraction (hydrogen atom on a secondary or t ertiary carbon atom), and of the calculation method. In each case, we local ised the transition state and showed that this transition state occurs earl y along the reaction coordinate. The results concerning the activation ener gies depend on the sites and the calculation methods. The calculated result s were compared to experimental ones. (C) 2000 Elsevier Science Ltd. All ri ghts reserved.