Nitrosation of Soil Organic Matter: III. Nature of Gases Produced by Reaction of Nitrite with Lignins, Humic Substances, and Phenolic Constituents Under Neutral and Slightly Acidic Conditions
Molecular nitrogen, nitrous oxide (N2O), nitric oxide (NO), and CO2 were identified in the gases formed by reacting NO2‐ with soils, humic and fulvic acids, lignins, lignin‐building units, and polyphenols in aqueous buffer solutions of pH 6 and 7 in the absence of oxygen. The composition of the mixture of gases was dependent upon the nature of the material examined, with relatively larger amounts of N2 being produced from the humic and fulvic acids. Compounds containing methoxyl groups failed to yield detectable amounts of methyl nitrite (CH3ONO) at the pH levels found in most soils. The reaction of NO with humic substances in the absence of oxygen led to the production of N2O and CO2.