Parafenyleenidiamiini

Parafenyleenidiamiini, often abbreviated as PPD, is an organic compound with the formula C6H4(NH2)2. It is a derivative of benzene with two amino groups attached at opposite (para) positions. PPD is a colorless solid that darkens in air due to oxidation. It is soluble in water and alcohols.

PPD is widely used as an intermediate in the synthesis of polymers, particularly aramids like Kevlar, which are known for their high strength and heat resistance. It also serves as a precursor for dyes and pigments, finding application in the textile and hair coloring industries. In rubber manufacturing, PPD acts as an antioxidant and antiozonant, protecting the material from degradation.

Despite its utility, PPD is a known skin sensitizer and can cause allergic contact dermatitis in susceptible individuals. This sensitivity can develop after repeated exposure. Consequently, its use in consumer products, especially hair dyes, is regulated in many regions, with maximum concentration limits often specified. Handling PPD requires appropriate safety precautions to minimize exposure.