Kinetic and mechanistic study of the atmospheric reaction of MBO331 with Cl atoms

Abstract

The present work deals with the reaction of 3-methyl-3-buten-1-ol (MBO331) with Cl atoms, which has been investigated by gas chromatography with flame ionization detection (GC-FID) at atmospheric pressure in N2 or air, using the relative rate technique. The rate constant reaction at 298 ± 1 K was found to be (5.01 ± 0.70) × 10−10 cm3 molecule−1 s−1, using cyclohexane, octane and 1-butene as a reference compounds. The temperature dependence for the reaction was studied within the 298−333 K range. Additionally, a product identification under atmospheric conditions has been performed for the first time by GC-MS, with 3-methyl-3-butenal, methacrolein and chloroacetone being observed as degradation products. A theoretical study on the reaction at the QCISD(T)/6-311G**//MP2/6-311G** level was also carried out to obtain more information on the mechanism. From the theoretical study it can be predicted that Cl addition to the double bond proceeds through lower energy barriers than H-abstraction pathways and therefore is energetically favoured. Finally, atmospheric implications of the results obtained are discussed.