Kinetics of the reactions of OH radicals with 2-methoxy-6-(trifluoromethyl)pyridine, diethylamine, and 1,1,3,3,3-pentamethyldisiloxan-1-ol at 298 ± 2 K
Tuazon, EC; Martin, P; Aschmann, SM; Arey, J; Atkinson, R
Rate constants for the reactions of 2-methoxy-6-(trifluoromethyl)pyridine, diethylamine, and 1,1,3,3,3-pentamethyldisiloxan-1-ol with OH radicals have been measured at 298 +/- 2 K using a relative rate method. The measured rate constants (cm(3) molecule(-1) s(-1)) are (1.54 +/- 0.21) x 10(-12) for 2-methoxy-6-(trifluoromethyl)pyridine, (1.19 +/- 0.25) x 10(-10) for diethylamine, and (1.76 +/- 0.38) x 10(-12) for 1,1,3,3,3-pentamethyldisiloxan-1-ol, where the indicated errors are the estimated overall uncertainties including those in the rate constants for the reference compounds. No reaction of 2-methoxy-6-(trifluoromethyl)pyridine with gaseous nitric acid was observed, and an upper limit to the rate constant for the reaction of 1,1,3,3,3-pentamethyldisiloxan-1-ol with O(3) of <7 x 10(-20) cm(3) molecule(-1) s(-1) was determined. Using a 12-h average daytime OH radical concentration of 2 x 10(6) molecule cm(-3), the lifetimes of the volatile organic compounds studied here with respect to reaction with OH radicals are 7.5 days for 2-methoxy-6-(trifluoromethyl) pyridine, 1.2 h for diethylamine, and 6.6 days for 1,1,3,3,3-pentamethyldisiloxan-1-ol. Likely reaction mechanisms are discussed. (C) 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 631-638, 2011