2,4-Dinitroaniline


2,4-Dinitroaniline is a chemical compound with a formula of C6H5N3O4. It is used as an explosive and as a reagent to detect and characterize aldehydes and ketones.

Preparation

2,4-Dinitroaniline can be prepared by reaction of 1-chloro-2,4-dinitrobenzene with ammonia.
It can be also prepared by the electrophilic aromatic substitution of aniline. Direct nitration should not be used due to the reactivity of aniline. Instead the acetyl protection should be used.

Basicity

Compared to aniline, the basicity of 2,4-dinitroaniline is even weaker. It is due to the electron-withdrawing nature of the nitro groups. This makes the pKa of conjugate acid of 2,4-dinitroaniline being even lower than that of hydronium ions, meaning that it is a strong acid.
The protons in the amino group is also much more acidic than that of aniline.

Uses

2,4-Dinitroaniline is usually used as an explosive. It is also used for the manufacture of azo dyes and disperse dyes, but also can be used as printing ink, toner and preparation of preservatives. and it is an intermediate for disperse dyes, neutral dyes, sulfur dyes, organic pigments.

Safety

2,4-Dinitroaniline is moderately toxic, with a lethal dose of 285 mg/kg. However, the main danger is that it is explosive and flammable with heat or friction.