High temperature reactions of OH radical with OH, H ₂, C ₂H ₆, CH ₃, and CH ₂

The reflected shock tube technique with a novel multi-pass absorption spectrometric detection method was used used to study reactions of OH radicals: OH + OH → H ₂O + O (1), OH + H ₂ → H ₂O + H (2), OH + C ₂H ₆ → H ₂O + C ₂H ₅ (3), OH + CH ₃ → ¹CH ₂ + H ₂O (4), and OH + CH ₂ → CH ₂O + H (5). The measurements were performed in single-shot experiments with low initial concentrations of hydroxyl radicals, [OH] ₀ = (5-15) ×10 ¹² molecule/cc, which allowed reliable isolation of the elementary reactions. The measured rate constants were: k ₁ = 5.2 × 10 ^-12 (at 1504 K) and 4.6 × 10 ^-12 (at 1545 K); k ₂ = 5.44 × 10 ^-11 exp(∼ 3220 K/T) (832-1359 K), k ₃ = 1.10 × 10 ^-10 exp(∼ 2537 K/T) (822-1367 K), k ₄ = 1.72 x 10 ^-11 exp(926 K/T) (834-2383 K), and k ₅ = (3.0 ± 2.4) × 10 ^-11 (1841-2324 K) (all in cc/molecule-sec). This is an abstract of a paper presented at the 228th ACS National Meeting (Philadelphia, PA, 8/22-26/2004).