Kinetics and mechanism of the tropospheric reaction of 3-hydroxy-3-methyl-2-butanone with Cl atoms.

The relative rate coefficient for the gas-phase reaction of 3-hydroxy-3-methyl-2-butanone (3H3M2B) with Cl atoms was determined under atmospheric conditions (298 ± 2 K, 720 ± 2 Torr). The products of the reaction were identified and quantified. This work provides the first kinetic and mechanistic determinations of the gas-phase reaction of Cl atoms with 3H3M2B. The rate measurements and the products studies were performed in two simulation chambers coupled to the gas chromatography-mass spectrometer (GC-MS) and the Fourier transform infrared (FTIR) techniques, respectively. The obtained average rate coefficient was (1.13 ± 0.17) × 10(-10) cm(3) molecule(-1) s(-1) using propene and 1,3-butadiene as reference compounds. The major primary reaction products observed in this study were (with % molar yields): acetic acid (42.6 ± 4.8) and 2,3-butanedione (17.2 ± 2.3). Results and mechanism are discussed in terms of the structure-reactivity relationship and compared with the reported reactivity with the other atmospheric oxidants. The atmospheric implications derived from this study are discussed as well.