An FTIR product study of the reaction between HCO and NO2

The product distribution of the reaction (1a) OH+NO+CO (1b) HNO+CO₂ (1c) H+NO+CO₂ (1d) HCO₂+NO (1e) (1f) (1g)was investigated at room temperature in the gas phase in Ar buffer gas at 570 mbar pressure by Fourier transform infrared (FTIR) spectroscopy. Mixtures of NO2/H2CO/Ar were photolyzed under stationary conditions using a high-pressure Hg lamp at λ = 300–340 nm. NO, CO, CO2, HONO, and H2O were found as major reaction products. A small amount of N2O was detected at long reaction times. From the yields of CO and CO2, branching ratios were found to be (k1a + k1b)/k1 = (0.66 ± 0.10) and (k1c + k1d + k1e)/k1 = (0.34 ± 0.10). The formation of HONO was attributed to reaction (1a) and/or reaction (1c) followed by the reaction HNO + NO2 → NO + HONO with a combined branching ratio of (k1a + k1c)/k1 = (0.28 ± 0.10).