Kinetics and mechanism of the reaction of propylene oxide with chlorine atoms and hydroxy radicals

The kinetics and mechanism of gas-phase propylene oxide (PPO) reactions were studied in a 142-L reaction chamber by long-path Fourier transform infrared spectroscopy at atmospheric pressure and 298 K. Rate coefficients for the reaction of PPO with ozone (O3), chlorine atoms (Cl), and hydroxyl radicals (OH) were measured using the relative rate technique. Product yields of acetic acid, acetic formic anhydride, formic acid, and carbon monoxide were determined for the following reactions: PPO with Cl both in the presence and absence of NO, PPO with OH and NO, methyl acetate with Cl both in the presence and absence of NO, and ethyl formate with Cl both in the presence and absence of NO. The measured rate coefficients for PPO with O3, Cl, and OH are <3.5 × 10−21 cm3 molecule−1 s−1, (3.0 ± 0.7) × 10−11 cm3 molecule−1 s−1, and (3.0 ± 1.0) × 10−13 cm3 molecule−1 s−1, respectively. The carbon balance for the products measured ranged from 10% (for OH + PPO) to 100% (for Cl + methyl acetate in the absence of NO). The mechanistic and atmospheric implications of these measurements are discussed. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 507–521, 2011