GAS-PHASE OZONOLYSIS OF ETHENE IN THE PRESENCE OF HYDROXYLIC COMPOUNDS

Ozonolysis of C2H4 was carried out at 295 K in 730 torr synthetic air in the concentration ranges of [O-3](0) = 1.9-8.2 ppm and [C2H4](0) = 4.0-15.0 ppm, in the absence and presence of the added HCOOH (1ppm), C H3COOH (1-10 ppm), and CH3OH (36-100 ppm). In the absence of the added compounds, a nearly complete analysis of the reaction products was ac hieved, with the yields expressed relative to the converted C2H4: HCHO 0.98, CO 0.26, CO2 0.18, HCOOH 0.05, and the sum of formic acid anhyd ride (FAN) and hydroperoxymethyl formate (HPMF), CHO-O-CH2OOH, 0.19. i n the presence of the added HCOOH, the yield of [FAN + HPMF] increased . The addition of CH,COOH suppressed the formation of FAN and HPMF com pletely. The addition of large excesses of CH3OH also decreased the yi eld of [FAN + HPMF] significantly In both cases, new products with the formula R-O-CH2OOH where R = CH2CO and CH3 for CH3COOH and CH3OH, res pectively, were formed. The present results, together with the formati on of hydroxymethyl hydroperoxide, HO-CH3OOH, with added water vapor ( Horie et al., Geophys. Res. Lett., 21, 1523, (1994)) were explained by the reaction of the Criegee biradical CH2OO with the added hydroxy co mpounds ROH. Formation of the products with the general formula R-O-CH 2OOH indicates that the RO-H bond fission has taken place. (C) 1996 Jo hn Wiley & Sons, Inc.