Phenylenediamine

Phenylenediamine (also known as p-Phenylenediamine, PPD, or 1,4-diaminobenzene) is an organic compound with the formula C6H4(NH2)2. This derivative of aniline is a white solid, but samples can darken due to air oxidation. It is mainly used as a component of engineering polymers and composites like kevlar. It is also an ingredient in hair dyes, textile dyes, pigment dyes, and rubber chemicals.

Chemical Structure and Properties

Phenylenediamine is an aromatic amine, consisting of a phenyl group (C6H5) attached to two amino groups (NH2) at the para position. It is a white solid at room temperature, but can darken upon exposure to air due to oxidation. It is slightly soluble in water and more soluble in organic solvents like ethanol and diethyl ether.

Uses

Phenylenediamine is primarily used in the chemical industry as a precursor to various polymers. In the production of kevlar, it is used as a co-monomer with terephthaloyl chloride. It is also used in the manufacture of rubber chemicals and pigments.

In the cosmetic industry, phenylenediamine is used as a primary ingredient in many oxidative hair dyes. It is also used in some textile dyes and fur dyes.

Health Effects

Exposure to phenylenediamine can cause a number of health effects. It is a strong allergen, and can cause contact dermatitis and other allergic reactions. It is also a known mutagen, and has been linked to an increased risk of bladder cancer in workers exposed to it.

Safety and Regulation

Due to its health effects, the use of phenylenediamine in cosmetics and hair dyes is regulated in many countries. In the European Union, it is classified as a Category 1B Reproductive toxin, and its use in cosmetics is restricted to certain concentrations.

See Also

• Aniline
• Kevlar
• Dermatitis
• Bladder cancer

References

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