Kinetic studies of OH reactions with H

The rate coefficients for the reactions of OH with H2O2, C3H8 and CH4 have been determined using a newly built pulsed laser photolysis-laser induced fluorescence (PLP-LIF) apparatus. While, the reaction of OH with H2O2 was studied at room temperature, the rate coefficients of OH reactions with CH4 and C3H8 were measured over a large range of temperature at P = 100 Torr of helium. The measured rate constant for the reaction of OH with H2O2 was k] = (1.75 ± 0.20) × 10-12 cm3 molecule-1 s-1. The kinetic data for C3H8 (k2) and CH4 (k3) were used to derive the Arrhenius expressions (in cm3 molecule-1 S-1) : k2 = (9.81 ± 0.11) × 10-12 exp[-(650 ± 30)/T] between 233 and 363 K, and k3 = (2.56 ± 0.53) × 10-12 exp[-(1765 ± 146)/T] between 233 and 343 K. The results obtained for k1 and k2 provide a validation of the PLP-LIF technique and those for k3 support the low value recently published, which has an important atmospheric impact