[2] Ethyl centralite is an important part of gunshot residue (GSR).

When a gun is fired, the chemical reactions from the burning of the propellant leave behind tiny particles called gunshot residue.

Ethyl centralite helps determine if a firearm was recently fired.

Ethyl centralite is also used as a plasticizer in the manufacturing of celluloid and enhances the flexibility and durability of the material.

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.

[4] The term "Centralite" was originally applied to dimethyldiphenylurea developed about 1906 at the German private military-industrial laboratory Zentralstelle für wissenschaftlich-technische Untersuchungen [de] (Center for Scientific-Technical Research) 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.

To benefit from their plasticizing qualities, they are commonly employed in propellants at higher fractions than diphenylamines.

This reaction involves the condensation of aniline (C₆H₅NH₂) with ethyl isocyanate (C₂H₅NCO).