Light-Absorbing Products Form during the Aqueous Phase Reaction of Phenolic Compounds in the Presence of Nitrate and Nitrite with UV Illumination

Phenolic compounds are emitted into earth’s atmosphere through industry and biomass burning events. These compounds may react in the gas or particle phase to form additional airborne pollutants. In this work, the aqueous phase chemical reactions of syringol, guaiacol, and catechol were studied in the presence of nitrate (NO-3 ) or nitrite ( NO-2) with and without UV illumination. The reactions were found to yield light absorbing products and electrospray ionization mass spectrometry (ESI-MS) experiments indicate some of the compounds formed may be the nitrated analogues of the starting organic compounds. However, infrared absorption data suggests the reaction products are composed of a complicated mixture. This suggests additional reactions occur simultaneously in solution. Treatment of the isolated reaction products with ozone (O3) suggest they are unstable and will eventually chemically decompose if/when formed in the atmosphere.