Measurement of Henry's law solubility and liquid-phase loss rate constants for acryloyl peroxynitrate (APAN) in deionized water at room temperature

Acryloyl peroxynitrate (APAN; molecular formula H2C = CHC(O)O2NO2) is a trace gas found in the troposphere in elevated concentration in biomass burning plumes and downwind from petrochemical plants. Owing to the reactivity of the unsaturated side chain, its synthesis poses a challenge to laboratory studies and the calibration of field instruments alike. Here, the generation of APAN from photolysis at 285 nm of acrolein in air in the presence of NOx (= NO + NO2) is described. Formation of APAN is primarily initiated by the abstraction of the aldehydic hydrogen by the hydroxyl radical (OH). The output of APAN was increased by the addition of acetone, which acts as a source of OH radicals. Photochemically generated APAN was used to measure its room temperature Henry's law solubility (H-S(cp)) and liquid phase loss rate (k(l)) constants in deionized water using a jacketed bubble column apparatus. The measured H(S)(cp )value for APAN was (2.67 +/- 0.10) M atm(- 1), where the error is at the 1 sigma level, and was on par with propionyl peroxynitrate (PPN). The k(l) value of APAN in deionized water was determined to be (2.7 +/- 0.4)x10(- 4) s(- 1), which is of similar magnitude as other PAN-type compounds.