Mechanistic studies of the atmospheric oxidation of methyl butenol by OH radicals, ozone and NO3 radicals

In a recent field study, strong indications have been obtained that 2-methyl-3-buten-2-ol (methyl butenol, MBO) is a compound emitted in important quantities by some types of vegetation. The atmospheric oxidation products from MBO are not yet well known. In this investigation we studied the reaction mechanisms and products of the reaction of MBO with OH radicals, O3 and NO3 radicals. All the experiments were performed in a 480 ℓ Teflon coated Pyrex glass chamber equipped with a long path length FTIR spectrometer. As products from the reaction between MBO and OH we identified and quantified acetone, glycolaldehyde, formaldehyde, formic acid, CO and CO2. From the reaction between MBO and O3, the products acetone, formaldehyde, formic acid, CO and CO2 have been identified; also, 2-hydroxy-2-methyl-propanal (HMPR) is tentatively put forward as a product on the basis of HPLC and GC-MS analysis of the DNPH derivative. Organic nitrates, peroxynitrates and carbonyl nitrates, together with acetone were observed as products of the reaction between MBO and the nitrate radical. Tentative reaction mechanisms for the oxidation of MBO by OH radicals, O3 and NO3 radicals are proposed.