Detailed kinetics of hydrogen abstraction from trans-decalin by OH radicals: the role of hindered internal rotation treatment

Abstract

In this study, the detailed kinetic mechanism of the trans-decalin + OH reaction is firstly investigated for a wide range of conditions (i.e., T = 200–2000 K & P = 0.76–76 000 Torr) using the M06-2X/aug-cc-pVTZ level and stochastic Rice–Ramsperger–Kassel–Marcus based master equation (RRKM-ME) rate model, which includes corrections of the hindered internal rotor (HIR) and tunneling effects. Our predicted global rate constant excellently matches with the scarce experimental measurement (R. Atkinson, et al. Int. J. Chem. Kinet., 1983, 15, 37–50). The H-abstraction channel from C_α of trans-decalin is found to be dominant at low temperatures. A U-shaped temperature-dependent behavior and slightly positive pressure-dependence at low temperatures (e.g., T ≤ 400 K & P = 760 Torr) of the total rate constants are also observed. Detailed analysis reveals that the HIR treatment is essential to capture the kinetic behavior while the tunneling correction only plays a minor role.