Nitrotriazolone

Nitrotriazolone is a cyclic semicarbazide-derived high explosive first identified in 1905, but not thoroughly researched until the 1980s. NTO is currently being used by the US Army in specialty insensitive munitions.
Nitrotriazolone is getting progressively adopted in novel explosive formulations, such as IMX-101, a new, safer alternative to TNT specially devised in 2010 by BAE Systems, where it is combined with 2,4-dinitroanisole and nitroguanidine. As such, NTO is found in the vast majority of IMX formulations. The Picatinny Arsenal has also adopted the implementation of NTO and DNAN in many of their likewise newly developed insensitive explosive mixtures, which share many of the same applications of the IMXs.

Properties

Nitrotriazolone shows keto–enol tautomerism through proton transfer reactions. The keto form shows significantly different stability to heat, friction, and impact.
Nitrotriazolone can form either a mono or dihydrate.

Preparation

NTO was first made in 1905 in a two step process. Semicarbazide hydrochloride is condensed with formic acid to produce 1,2,4-triazol-3-one, which is nitrated with nitric acid to form nitrotriazolone.

Toxicity

In vivo studies showed the nitrotriazolone is absorbed through the skin and gastrointestinal tract. In the kidneys, NTO is broken down into 5-amino-1,2,4-triazol-3-one, which undergoes oxidative denitrification and forms urazoles and nitrites in rats.