Centralite
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Names | |
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Preferred IUPAC name
N,N′-Diethyl-N,N′-diphenylurea | |
Other names
Centralite 1
Carbamite Ethyl centralite N,N′-Diethylcarbanilide Bis(N-ethyl-N-phenyl)urea 1,3-Diethyl-1,3-diphenylurea sym-Diethyldiphenylurea USAF EK-1047 | |
Identifiers | |
3D model (JSmol)
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ChemSpider | |
ECHA InfoCard | 100.001.496 |
PubChem CID
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
C17H20N2O | |
Molar mass | 268.360 g·mol−1 |
Appearance | White to light grey crystalline powder |
Density | 0.8 g/cm3 |
Insoluble | |
Solubility in Acetone, ethanol and benzene | Soluble |
-134.05·10−6 cm3/mol | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Centralite (empirical formula: C17H20N2O) is a gunshot residue also known as ethyl centralite. Its IUPAC name is 1,3-diethyl-1,3-diphenylurea. Ethyl centralite is insoluble in water, but is soluble in acetone, ethanol and benzene. It is mainly used as a burning rate moderator and stabilizer for smokeless powder, and also a plasticizer for celluloid.[2]
History
[edit]In the 19th century chemists identified that nitrocellulose can destroy itself with the help of nitrogen oxides separating from it at storage, and tried to find bases which might capture those oxides. Urea has been used for stabilizing celluloid in the 19th century (and even in early American military powders), but like other water-soluble bases, it also attacks nitrocellulose, so German chemists substituted hydrogen atoms with nonpolar organic radicals to diminish this effect.[3]
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Naming
[edit]The term "Centralite" was originally applied to dimethyldiphenylurea developed about 1906 at the German Central War Laboratory Zentralstelle für wissenschaftlich-technische Untersuchungen in Neubabelsberg as a deterrent coating for smokeless powder in military rifle cartridges. Thereafter, all hydrocarbon-substituted symmetrical diphenyl urea compounds used as smokeless powder deterrents (or moderants) were called centralites after the laboratory. The preferred ethyl centralite became known as Centralite No. 1 and the original methyl centralite was identified as Centralite No. 2. Butyl centralite was also used as a celluloid plasticizer.[4][5]
Comparison with analogs
[edit]Compared to diphenylurea, it has a far more convoluted reaction history. Finally, nitrated anilines are produced. Centralite-2, also known as sym-dimethyldiphenylurea, is a methyl analog that is moderately utilized overseas. Though they are likewise excellent plasticizers, centralites are thought to be a little less effective stabilizer than 2-nitrodiphenylamine. To benefit from their plasticizing qualities, they are commonly employed in propellants at higher fractions than diphenylamines.
References
[edit]- ^ CID 6828 from PubChem
- ^ "Ethyl centralite / Centralite I, CAS: 85-98-3 - Synthesia". organics.synthesia.eu. Retrieved 2023-11-02.
- ^ "Explosives". Philadelphia, P. Blakiston. 1917.
- ^ Davis, Tenney L. (1943). The Chemistry of Powder & Explosives (Angriff Press [1992] ed.). John Wiley & Sons Inc. pp. 317–320. ISBN 0-913022-00-4.
- ^ Davis, William C. Jr. (1981). Handloading. National Rifle Association of America. p. 130. ISBN 0-935998-34-9.