Products of the Gas-Phase Reactions of the OH Radical with 1-Methoxy-2-propanol and 2-Butoxyethanol

Glycol ethers are used as solvents and are hence liable to be released to the atmosphere, where they react and contribute to the formation of photochemical air pollution. In this work, products of the gas-phase reactions of the OH radical with 1-methoxy-2-propanol and 2-butoxyethanol in the presence of NO have been investigated at 298 ± 2 K and 740 Torr total pressure of air by gas chromatography, in situ Fourier transform infrared spectroscopy, and in situ atmospheric pressure ionization tandem mass spectrometry. The products observed from 1-methoxy-2-propanol were methyl formate, methoxyacetone, and acetaldehyde with molar formation yields of 0.59 ± 0.05, 0.39 ± 0.04, and 0.56 ± 0.07, respectively. The products observed and quantified from 2-butoxyethanol were n-butyl formate, 2-hydroxyethyl formate, propanal, 3-hydroxybutyl formate, and an organic nitrate (attributed to CH3CH2CH2CH2OCH(ONO2)CH2OH and its isomers), with molar formation yields of 0.57 ± 0.05, 0.22 ± 0.05, 0.21 ± 0.02, 0.07 ± 0.03, and 0.10 ± 0.03, respectively. An additional product of molecular weight 132, attributed to one or more hydroxycarbonyl products, was also observed from the 2-butoxyethanol reaction by atmospheric pressure ionization mass spectrometry. For both glycol ethers, the majority of the reaction products and reaction pathways are accounted for, and detailed reaction mechanisms are presented which account for the observed products.