Rate coefficient for the reaction of OH with CH2=C(CH3)C(O)OONO2 (MPAN)

The rate coefficient for reaction of OH with CH2=C(CH3)C(O)OONO2 (MPAN, peroxymethacrylic nitric anhydride), k3, has been determined using a relative rate technique. Consistent results were obtained with ethene and propene as the reference compound, and a rate coefficient of k3=(3.2±0.8)×10−11 cm3 molecule−1 s−1 is reported at 275±3 K. This value is about a factor of eight larger than the only previous report. A brief investigation of the products of the OH-initiated oxidation of MPAN and methacrylic acid (CH2=C(CH3)COOH, an impurity in the MPAN sample but also a structural analog of MPAN) is also reported. Major products obtained in the case of methacrylic acid were CH2O and pyruvic acid (CH3C(O)C(O)OH), while CH2O, CO2, and possibly hydroxyacetone are observed in the case of MPAN. The atmospheric implications of the results are briefly discussed.