Hiffr kinetics studies. Temperature dependence of Al/O 2 and AlO/O 2 kinetics from 300 to 1700/1400 K

Abstract

A high-temperature fast-flow reactor (HTFFR) has been adapted for the near room temperature study of the kinetics of atoms and free radicals of refractory species. The rate coefficients of the reactions Al+O2→(1)AlO+O and Al+O2→(2)AlO2+O have been found to be (3.4±2.3)×10−11 and (7.2±3.6)×10−13 ml molecule−1 sec−1, respectively at 310 K. Combining these results with high temperature HTFFR measurements leads to the recommended values k1 (300–1700 K)=(3.4±2.2)×10−11 and k2(300–1400 K)=(4.8±3.1)×10−13 ml molecule−1 sec−1. The remarkable absence of a positive temperature dependence for these rate coefficients over such large temperature ranges is discussed. In the case of Reaction (2) this absence indicates D(O−AlO)>-D(O−O)=118 kcal mole−1, consistent with the re-interpreted previous determination of this bond energy of 121.5±2 kcal mole−1 (508±8 kJ mole−1).