The Nef reaction is an organic reaction describing the acid hydrolysis of a salt of a primary or secondary nitroalkane to an aldehyde or a ketone and nitrous oxide. John Ulric Nef treated the sodium salt of nitroethane with sulfuric acid resulting in an 85–89% yield of nitrous oxide and at least 70% yield of acetaldehyde.
Nef reaction mechanism includes
The nef reaction mechanism will start with the nitronate salt protonation, which will give nitronic acid. Nitronate salt is once again protonated and resulted in the formation of iminium ion. This intermediate is attacked by water in a nucleophilic addition forming which loses a proton and then water to the 1-nitroso-alkanol. This intermediate rearranges to hyponitrous acid and the oxonium ion which loses a proton to form the carbonyl compound.