Citation

Lemberger N, Almog J. J. Forensic Sci. 2007; 52(5): 1107-1110.

Affiliation

Casali Institute of Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.

Copyright

(Copyright © 2007, American Society for Testing and Materials, Publisher John Wiley and Sons)

DOI

10.1111/j.1556-4029.2007.00504.x

PMID

17645742

Abstract

Urea nitrate (uronium nitrate, UN) is a powerful, improvised explosive that can be easily made from urea and nitric acid. It is considered the most frequently used, illegal explosive in the Israeli arena, which is responsible for the loss of more than a hundred lives in terrorist incidents. Urea nitrate is a colorless, crystalline substance that looks very much like sugar. A sensitive color test for UN was developed recently. It is based on the formation of a red dye in the reaction between p-dimethylaminocinnamaldehyde and UN under neutral conditions. A similar reaction with p-dimethylaminobezaldehyde produces a yellow dye. The two dyes have been synthesized, and their structures determined by X-ray crystallography. Both dyes are protonated Schiff bases, prevailing in the crystal in a quinoid form. They are identical to the compounds, which are obtained in the colorimetric detection of urea with the same reagents, under strong acidic conditions, whose structures have been postulated in the literature, but never fully proved experimentally.

Language: en