Products of the gas-phase reactions of 1,3-butadiene with OH and NO3 radicals

1,3-Butadiene is emitted into the atmosphere from a number of sources including combustion sources and is listed in the United States as a hazardous air pollutant. In the atmosphere, 1,3-butadiene reacts with OH radicals, NO3 radicals, and O-3 with the dominant tropospheric removal processes being daytime reaction with the OH radical and nighttime reaction with the NO3 radical. We have used gas chromatography, in situ Fourier transform infrared (FTIR) absorption spectroscopy, and in situ atmospheric pressure ionization tandem mass spectrometry (API-MS) to identify and quantify the products formed from the reactions of 1,3-butadiene with OH radicals (in the presence of NO) and NO3 radicals. Acrolein, formaldehyde, and furan were identified and quantified from the OH radical-initiated reaction, with formation yields of 0.58 +/- 0.04, 0.62 +/- 0.05, and 0.03-0.04, respectively. Organic nitrates were observed by FT-IR spectroscopy with an estimated yield of 0.07 +/- 0.03, and the API-MS analyses indicated that these organic nitrates are mainly the hydroxynitrate HOCH2CH=CHCH2ONO2 and/or its isomers. API-MS analyses showed the formation of a hydroxycarbonyl with the formula C4H6O2, attributed to HOCH2CH=CHCHO and/or its isomers. The major products of the NO3 radical-initiated reaction were organic nitrates; the API-MS analyses indicated the formation of acrolein, 1,2-epoxy-3-butene, and unsaturated C-4-hydroxycarbonyls, hydroxynitrates, carbonyl nitrates, and nitrooxyhydroperoxides. Acrolein, HCHO, and furan were again quantified by gas chromatographic and FT-IR analyses. Our data are compared with previous literature studies, and detailed reaction mechanisms are presented and discussed.