Rate Coefficients for the OH + Pinonaldehyde (C10H16O2) Reaction between 297 and 374 K

The rate coefficient for the reaction of OH with pinonaldehyde (C10H16O2, 3-acetyl-2,2-dimethyl-cyclobutyl-ethanal), a product of the atmospheric oxidation of α-pinene, was measured under pseudo-first-order conditions in OH at temperatures between 297 and 374 K at 55 and 96 Torr (He). Laser induced fluorescence (LIF) was used to monitor OH in the presence of pinonaldehyde following its production by 248 nm pulsed laser photolysis of H2O2. The reaction exhibits a negative temperature dependence with an Arrhenius expression of k 1(T) = (4.5 ± 1.3) × 10-12 exp((600 ± 100)/T) cm3 molecule-1 s-1; k 1(297 K) = (3.46 ± 0.4) × 10-11 cm3 molecule-1 s-1. There was no observed dependence of the rate coefficient on pressure. Our results are compared with previous relative rate determinations of k 1 near 297 K and the discrepancies are discussed. The state of knowledge for the atmospheric processing of pinonaldehyde is reviewed, and its role as a marker for α-pinene (monoterpene) chemistry in the atmosphere is discussed.