Nitrous acid in the presence of hydrogen peroxide

Kortum and Finckh [167] found the absorption spectrum of the yellow solution was similar to that of the nitrate ion, showing however some difference. 

The kinetics of the reaction of nitrous acid with hydrogen peroxide have been 

The experiments so far performed have sometimes been contradictory, but they have led to the conclusion that pemitrous acid does exist. 

Nitration with pernitrous acid. The first investigations into the nitration of benzene with per-nitrous acid were performed by Trifonov [166], In 1922 he found o- nitrophenol to be the reaction product and suggested the application of the reaction for detecting benzene and other aromatic hydrocarbons. His results were confirmed by the experiments of Halfpenny and P. L. Robinson [170], 

It has been shown that aromatic hydrocarbons can be nitrated by pemitrous acid even at very low acid concentrations (e.g. 2%) at room temperature. The hydroxylation of the hydrocarbon takes place simultaneously in many cases. A characteristic feature of the reaction is that the nitro group mostly takes the meta position with respect to the substituent already present. If a nitro and a hydroxyl group are introduced simultaneously the hydroxyl group nearly always takes the ortho or para position with respect to the substituent already present. Diphenyl derivatives are also formed. 

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