Gaseous nitrous acid (HONO) was produced in a discharge flow-mass spectrometric system by the reaction of hydroxyl radicals with nitric oxide, OH + NO + M ￫ HONO + M. A peak was observed at mass 47 (the parent peak of nitrous acid) showing that the acid could be detected mass spectrometrically. A totally satisfactory source of hydroxyl radicals could not be found and so studies of the reactions of nitrous acid could not be undertaken. The reactions of ozone with methyl and ethyl nitrites were studied in a static reaction vessel using an infrared spectrometer for analyses. The reactions were found to be the simple oxidations yielding the nitrates RONO + O₃ ￫ RONO₂ + O₂ The rate expressions obtained for these reactions were

[EQUATION]

The only unusual feature of these reactions was the unexplained extraordinarily low value of the Arrhenius parameter in the ethyl nitrite reaction. The reactions of hydrogen atoms with methyl and ethyl nitrites were studied in a discharge flow-mass spectrometric system. The products observed in the methyl nitrite reaction were hydrogen, nitric oxide, methane, water and formaldehyde. Methanol was detected at higher pressures with either methoxy radicals or nitroxyl molecules (or perhaps both) detected as intermediates. The products detected from the ethyl nitrite reaction were hydrogen, nitric oxide, ethane, water and possibly formaldehyde. Ethanol was detected at higher pressures, with acetaldehyde, the ethoxy radical and nitroxyl molecule detected as intermediates. Several products were verified by reacting the nitrite with deuterium atoms. The primary reactions were shown to be :

[EQUATION]

where in the methyl nitrite reaction the yield of methane was found to be 8.7±1.5% of the consumed nitrite. The primary rate constant expressions obtained for the loss

[EQUATION]