Study of OH-initiated degradation of 2-aminoethanol

The degradation of 2-aminoethanol (MEA) by the hydroxyl radical (OH) was studied in the European Photoreactor (EUPHORE), a large outdoor environmental chamber. High-Temperature Proton-Transfer-Reaction Mass Spectrometry (HT-PTR-MS) and Fast Fourier Transform In- frared (FT-IR) were used to follow concentrations of reac- tants in the gas phase. Aerosol mass concentrations were tracked with Aerosol Mass Spectrometry (AMS). The cham- ber aerosol model MAFOR was applied to quantify losses of MEA to the particle phase. The rate constant k(OH + MEA) was determined relative to the rate constant of the 1,3,5- trimethylbenzene reaction with OH and was found to be (9.2± 1.1)◊10 11 cm 3 molecule 1 s 1 , and thus the reac- tion between OH radicals and MEA proceeds a factor of 2-3 faster than estimated by structure-activity relationship (SAR) methods. Main uncertainty of the relative rate de- termination is the unknown temporal behaviour of the loss rate of MEA to chamber wall surfaces during the sunlit ex- periments. Nucleation and growth of particles observed in the experiments could be reproduced by the chamber model that accounted for condensation of gaseous oxidation prod- ucts, condensation of ethanolaminium nitrate and nucleation involving MEA and nitric acid.