Mechanism of denitration of nitroguanidines in concentrated acids. Some new evidence

Abstract

Previous work on the mechanism of the reversible denitration of nitroguanidines receives support from proton magnetic resonance studies of the nature of nitroguanidines in concentrated sulphuric acid, and some new kinetic results in methanesulphonic acid solutions. The rates of addition of first and second protons in the acid regions used for previous kinetic studies are quite in keeping with a diprotonated nitroguanidine species as the reactive intermediate in denitration. The sites of proton addition (nitrimino- and amino-groups) can also be gauged from the proton spectra. The previous kinetic work is re-analysed in view of the revised H₀ data now available, but the original conclusions are unaltered.