Products and Mechanism of the Reactions of OH Radicals and Cl Atoms with Methyl methacrylate (CH2=C(CH3)C(O)OCH3) in the Presence of NOx

M. B .BLANCO, I. BEJAN, I. BARNES, P. WIESEN AND M.A. TERUEL

ENVIRONMENTAL SCIENCE & TECHNOLOGY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2014 vol. 48 p. 1692 - 1699

0013-936X

The OH radical and Cl atom initiated photodegradation of methyl methacrylate has been investigated in a 1080 L quartz-glass environmental chamber at 298  2 K and atmospheric pressure of synthetic air using in situ FTIR spectroscopy to monitor the reactants and products. The major products observed in the OH reaction were methyl pyruvate (92  16) % together with the formaldehyde (87  12) % co-product from the C1-C2 bond cleavage channel of the intermediate 1,2-hydroxyalkoxy radical, formed by addition of OH to the terminal carbon of the double bond which is designated C1. For the Cl atom reaction the products identified were chloroacetone (41  6) % together with its co-product formaldehyde (35  5) % and methyl pyruvate (24  4) % together with its coproduct formylchloride (25  4) %. The results show that the fate of the intermediate 1,2-chloroalkoxy radical involves not only cleavage of the C1-C2 bond but also quite substantial cleavage of the C2-C3 bond. The present results are compared with previous studies, showing different branching ratios for the OH and Cl addition reactions in the presence of NOx. Atmospheric implications are discussed.