Nitration of compounds containing acidic hydrogen

The reaction between formaldehyde and compounds containing acidic protons is probably the most important route to polyols. Some of these polyols have been 0-nitrated and used as practical explosives. The condensation of nitromethane and nitroethane with excess formaldehyde in the presence of potassium hydrogen carbonate yields tris(hydroxymethyl)nitromethane (58) and l,l-bis(hydroxymethyl)nitroethane (60) respectively. The nitration of (58) and (60) with either absolute nitric acid or mixed acid gives the secondary high explosives, (59) and (61) respectively. 

Hydrogen sulfide may act in several ways. Either it is reoxidized to sulfuric acid under aerobic conditions [101] or in the presence of compounds such as nitrate or it may react with cations to form metal sulfides that precipitate [50]. Further, H2S may be oxidized anaerobically in the light by photosynthetic bacteria (mostly to sulfur, sometimes to sulfate). In the case of materials containing acid-reactive substances, the biogenic acid will become harmful. In the case of metals the presence of H2S may cause MIC. Another source of H2S is not restricted to anaerobiosis. Amino acids containing sulfur are degraded under aerobic conditions, giving rise to H2S (cysteine and cystine). 

If an aromatic compound contains saturated aliphatic side chains nitration carried out under the above conditions takes place always in the benzene nucleus and not in the side chain. Since the carbon atoms of benzene are each united directly to only one hydrogen atom, the nitro-derivatives obtained are tertiary and therefore incapable of forming salts, nitrolic acids, or pseudonitroles, as do the primary and secondary nitro-compounds. 

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