Kinetics of OH and Cl reactions with a series of aldehydes

The rate constants for the reactions of the OH radicals with a series of aldehydes have been measured in the temperature range 243-372 K, using the pulsed laser photolysis-pulsed laser induced fluorescence method. The obtained data for propanaldehyde. iso-butyraldehyde, tert-butyraldehyde, and n-pentaldehyde were as follows (in cm(3) molecule(-1) s(-1)): (a) in the Arrhenius form: (5.3 +/- 0.5) x 10(-12) exp[(405 +/- 30)/T], (7.3 +/- 1.9) x 10(-12) exp[(390 +/- 78)/T], (4.7 +/- 0.8) x 10(-12) exp[(564 +/- 52)/T], and (9.9 +/- 1.9) x 10(-12) exp[(306 +/- 56)/T]: (b) at 298 K: (2.0 +/- 0.3) x 10(-11), (2.6 +/- 0.4) x 10(-11), (2.7 +/- 0.4) x 10(-11), and (2.8 +/- 0.2) x 10(-11), respectively. In addition, using the relative rate method and alkanes as the reference compounds. the room-temperature rate constants have been measured for the reactions of chlorine atoms with propanaldehyde, iso-butyraldehyde, tert-butyraldehyde, n-pentaldehyde, acrolein, and crotonaldehyde. The obtained valves were (in cm(3) molecule(-1) s-): (1.4 +/- 0.3) x 10(-10), (1.7 +/- 0.3)10(-10), (1.6 +/- 0.3) x 10(-10), (2.6 +/- 0.3) x 10(-10), (2.2 +/- 0.3) x 10(-10), and (2.6 +/- 0.3) x 10(-10), respectively. The results are presented and discussed in terms of structure-reactivity relationships and atmospheric importance. (C) 2000 John Wiley & Sons, Inc.