Multifunctional acid formation from the gas-phase ozonolysis of β-pinene

Abstract

The gas-phase ozonolysis of β-pinene was studied in static chamber experiments, using gas chromatography coupled to mass spectrometric and flame ionisation detection to separate and detect products. A range of multifunctional organic acids—including pinic acid, norpinic acid, pinalic-3-acid, pinalic-4-acid, norpinalic acid and OH-pinalic acid—were identified in the condensed phase after derivatisation. Formation yields for these products under systematically varying reaction conditions (by adding different OH radical scavengers and Criegee intermediate scavengers) were investigated and compared with those observed from α-pinene ozonolysis, allowing detailed information on product formation mechanisms to be elucidated. In addition, branching ratios for the initial steps of the reaction were inferred from quantitative measurements of primary carbonyl formation. Atmospheric implications of this work are discussed.