Atmospheric degradation of 2-Isopropoxyethanol: Reactions with Cl, OH and NO3

Abstract

The use of glycol ethers as solvents and chemical intermediates has increased markedly in recent years. Once released into the atmosphere, they can undergo degradation processes mainly by reactions with the atmospheric oxidants that can have significant effects on the environment. In this work, the kinetic and products study of reactions of 2-isopropoxyethanol (2-iPE, (CH3)2CHOCH2CH2OH) with OH and NO3 radicals and Cl atoms have been performed using FTIR (Fourier Transform Infrared Spectroscopy) and GC-MS (Gas Chromatography/Mass Spectrometry) as detection techniques. The rate coefficients obtained were (units cm3 molecule−1 s−1): (2.18 ± 0.15) × 10−10, (1.88 ± 0.10) × 10−11 and (3.16 ± 0.45) × 10−15 for Cl, OH· and NO3· reactions, respectively. The kinetic results obtained have been included in comparison tables of the general reactivity of hydroxy ethers to extract conclusions of the atmospheric behaviour of this type of compounds. The main products detected and quantified have been isopropyl formate, formaldehyde, 2-hydroxyethyl acetate and, in the case of NO3· reactions, nitrated compounds. A reaction mechanism has been proposed according to the reaction products obtained. The calculated lifetimes have been determined and Global Warming Potential (GWP) and Photochemical Ozone Creation Potential (POCPE) have been estimated, concluding, first, that the reaction with OH radicals is the main pathway of degradation of this and others glycol ethers in the atmosphere, second, that these compounds have GWP negligible and third, that they could have influence on ozone generation at local and regional level.