The hydroxyl radical reaction rate constant and products of methyl isobutyrate

The relative rate technique has been used to measure the rate coefficient f or the reaction of the hydroxyl radical (OH) with methyl isobutyrate (MIB, (CH3)(2) CHC(=O)-O-CH3) to be (1.7 +/- 0.4) x 10(-12) cm(3)molecule(-1)s(-1 ) at 297 +/- 3 K and 1 atmosphere total pressure. To more clearly define MI B's atmospheric degradation mechanism, the products of the OH + MIB reactio n were also determined. The observed products and their yields were: aceton e (97 +/- 1%, (CH3)(2)C(=O)) and methyl pyruvate (MP, 3.3 +/- 0.3%, CH3C(=O )C(=O)-O-CH3). The products' formation pathways are discussed in light of c urrent understanding of the atmospheric chemistry of oxygenated organic com pounds. (C) 1999 John Wiley & Sons, Inc.