Atmospheric reactions of volatile organic compounds and their products

Volatile organic compounds (VOCs) are emitted into the atmosphere from both biogenic and anthropogenic sources. Once released, these VOCs can react with ozone (O3), hydroxyl (OH) radicals, and nitrate (NO3 ) radicals in the atmosphere. The kinetics and products of the atmospherically-relevant reactions of selected VOCs were investigated in this work.; Reactions were carried out in environmental chambers to better understand the reactions of stabilized Criegee Intermediates formed from the reactions of 1-octene, trans-7-tetradecene, 1,2-dimethyl-1-cyclohexene, and alpha-pinene with O3. The products formed were analyzed using atmospheric ionization mass spectrometry (API-MS/MS) and gas chromatography with flame ionization detection (GC-FID).; The kinetics of four C7 carbonyls (each of which have a molecular weight of 110 and two being isomers of each other) formed from the ozonolysis of three monoterpenes (myrcene, ocimene, and terpinolene) were measured using relative rate methods. Since these carbonyls are not commercially available, they were first synthesized by the liquid phase ozonolysis of the parent monoterpenes. The carbonyl was then purified and identified using 1H NMR. Their rate constants with O3, OH and NO3 radicals were then measured.; The reactions of 1,3-butadiene and isoprene with OH radicals have been studied previously, yet approximately 20--40% of the products remain unaccounted for, although hydroxycarbonyls have been previously been detected, but not quantified, in those reactions. In this work, the hydroxycarbonyls were observed using API-MS in negative ion mode as their NO2 - adducts and by solid phase micro extraction (SPME) fibers precoated with a derivatizing agent for on-fiber derivatization of carbonyl compounds. The hydroxycarbonyl yields were measured in addition to their rate constants for reaction with OH radicals. Because hydroxyaldehydes are not commercially available and they do not elute from GC columns without prior derivatization, we produced a series of hydroxyaldehydes in situ from the reactions of diols and unsaturated alcohols with OH radicals, and determined their OH radical reaction rate constants by monitoring the hydroxyaldehydes during the OH-diol (or OH-unsaturated alcohol) reactions) using precoated SPME fibers. We extended this work to determine the OH radical reaction rate constants for a series of 1,4-hydroxyketones formed from the alkanes n-pentane through n-octane.