Atmospheric Degradation of CH2=C(CH3)C(O)OCH3 Initiated by OH Radicals: Mechanistic Study and Quantification of CH3C(O)C(O)OCH3 in NOx Free Air.

RODRIGO G. GIBILISCO, JORGE G. URANGA, ANA N. SANTIAGO AND MARIANO A. TERUEL

AMER CHEMICAL SOC

Lugar: Washington; Año: 2015 vol. 119 p. 8775 - 8775

he product distribution of the gas-phase reaction of OH radicals with methyl methacrylate (CH2=C(CH3)C(O)OCH3, MMA) in the absence of NOx was studied at 298 K and atmospheric pressure of air. The experiments were performed in a Teflon chamber using solid phase microextraction (SPME) with GC-MS and GC-FID for product identification and quantification, respectively. In the absence of NOx, methyl pyruvate (CH3C(O)C(O)OCH3) was identified with a yield of (76 ± 13) % in accordance with the decomposition of the 1,2-hydroxyalkoxy radicals formed.In addition, a detailed quantum chemical study of the degradation of MMA was performed by Density Functional Theory (DFT) methods using the MPWB1K functional. This calculation suggests that formation of methyl pyruvate, from C1-C2 scission of 1,2-hydroxyalkoxy radical, is kinetically and thermodynamically the most favorable reaction path taking into account the electronic properties of reaction intermediates and transition states. The difference obse