INVESTIGATION OF HYDROXYL RADICAL REACTIONS WITH ORTHO-XYLENE AND META-XYLENE IN A CONTINUOUS STIRRED TANK REACTOR

The gas-phase reactions of hydroxyl radicals with o-xylene and m-xylene were studied in a continuous stirred tank reactor. Gas and aerosol products accounted for 65-85% of the reacted carbon. Approximately 19 and 13% of the original o-xylene and m-xylene oxidation were estimated to have occurred through methyl hyrogen abstraction by OH, primarily leading to methylbenzyl nitrates and tolualdehydes. The remaining mass reacted through the OH addition pathway forming dimethylphenols, nitrodimethylphenols, nitroxylenes, and stable products resulting from reacton of metastable O//2-OH adducts. For o-xylene, the ratio of the rate constants for formation of nitroxylenes vs. dimethylphenols was estimated to be 5. 9 multiplied by 10** 4, while the same value for m-xylene was only about 1. 0 multiplied by 10**4. The ratios of the dimethylphenol formation rates to the oxygen addition rates were found to be greater than or equal to 0. 15 for o-xylene and 0. 27 for m-xylene.