Chemical Safety: Preparation And Use Of Nitroacetonitrile

The chemistry group at the National Institutes of Health Chemical Genomics Center wishes to alert readers on the volatile nature of nitroacetonitrile (CAS No. 13218-13-8), which caused a recent explosion in our laboratories that, fortunately, did not result in harm to individuals or property. A chemist was performing a dehydration of 2-nitroacetaldehyde oxime to nitroacetonitrile using thionyl chloride in diethyl ether (diethyl ether was from a freshly opened bottle) at 40 ºC for one hour (following a reported literature procedure: J. Org. Chem. 1960, 25, 266; J. Med. Chem. 1986, 29, 1046, but working on a substantially smaller scale).

The reaction mixture was subsequently filtered to remove precipitate, and the filtrate was washed with water. The diethyl ether layer was separated, dried with sodium sulfate, filtered, and concentrated under reduced pressure. Note: Some diethyl ether remained at this point. The round-bottom flask remained vented and was placed in the back of the hood. Approximately one hour later, an explosion occurred. Numerous reports do not advise on the explosive nature of nitroacetonitrile, and we have noted only one report that suggests reagents of this type are potentially explosive (Can. J. Chem. 1959, 37, 1266). The mechanism of the violent decomposition has not been determined.

Craig J. Thomas
Bethesda, Md.