P-Phenylenediamine

P-Phenylenediamine (also known as PPD, 1,4-diaminobenzene, or 1,4-phenylenediamine) 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.

Chemical Structure and Properties[edit | edit source]

P-Phenylenediamine is a derivative of benzene, and is structurally similar to aniline, with the difference that the amino group (-NH2) on the para position is replaced by a phenyl group (-C6H5). It is a white solid, but can darken upon exposure to air due to oxidation. It is slightly soluble in water and more so in organic solvents.

Uses[edit | edit source]

P-Phenylenediamine is primarily used in the manufacture of polymers, including kevlar and other aramid fibers. It is also used in the production of rubber chemicals, textile dyes and pigments. PPD is also used in hair dyes as a permanent dye, where it is mixed with hydrogen peroxide to create the dye.

Health Effects[edit | edit source]

Exposure to P-Phenylenediamine can cause a number of health effects, including dermatitis, asthma, and in severe cases, anaphylaxis. It is also a known carcinogen, and has been linked to bladder cancer and non-Hodgkin lymphoma.

Regulation[edit | edit source]

Due to its health effects, the use of P-Phenylenediamine in cosmetics and hair dyes is regulated in many countries. In the European Union, it is classified as a Category 1 carcinogen and its use in cosmetics is restricted.