GAS-PHASE REACTION OF N-BUTYL ACETATE WITH THE HYDROXYL RADICAL UNDERSIMULATED TROPOSPHERIC CONDITIONS - RELATIVE RATE-CONSTANT AND PRODUCT STUDY

The gas-phase reaction of n-butyl acetate with hydroxyl radicals has b een studied in an environmental smog chamber at 298 K, atmospheric pre ssure, and simulated tropospheric concentrations. The rate constant fo r this reaction has been determined by a relative method and the exper imental result, relative to n-octane used as reference compound, is k = 5.2 +/- 0.5 X 10(-12) cm(3) molecule(-1) s(-1) This value appears to be about 25% higher than absolute rate constants found in the literat ure, but agrees very well with the other relative determination. Two r eaction products have been identified and their production yield has b een estimated, each accounting for about (15 +/- 5)% of the overall OH reaction processes. The two observed products are 2-oxobutyl acetate (CH3-CO-O-CH2-CO-CH2-CH3) and 3-oxobutyl acetate (CH3-CO-O-CH2-CH2-CO- CH3) The accuracy of the relative rate constant obtained is examined c onsidering the evolution of the reactivity of the alkoxy end of the es ters. Formation mechanisms for the two observed products are proposed and the likely other degradation channels are discussed. (C) 1996 John Wiley & Sons, Inc.