The introduction of p-Phenylenediamine

Description

P-phenylenediamine (PDD) is a white to purple crystalline solid (melting point 234 F) that turns purple to black in the air. P-Phenylenediamine (PPD), a derivative of p-nitroanaline, is found in the plastic and chemical industries as a byproduct of manufacturing. PPD has a strong protein binding ability to penetrate deeply into the hair. It is widely used as an oxidizable hair dye for its free availability and low cost. PPD is found in over 1000 hair dye formulations and is the most frequently used permanent hair dye component in Europe, North America, and East Asia. PPD-containing hair dyes have been associated with cancer and mutagenicity. In addition, this chemical is used as a substitute for henna and in manufacturing rubber and certain polymers[1].

Uses

P-phenylenediamine is part of a class of chemicals called aromatic amines, found in the plastic and chemical industries as byproducts of manufacturing. In addition to hair dyes, this chemical is used to manufacture rubber and certain polymers, such as Kevlar. It is used for the production of aramid fiber and antioxidants, as a laboratory reagent, in photographic development, and as a dye for hair and furs.

Consumers are primarily exposed to p-phenylenediamine (PPD) through its use in permanent hair dyes that rely on chemical reactions (called oxidation) to fix the color where it is found in concentrations of about 4 percent. PPD reacts with hydrogen peroxide to bind the color to the hair permanently. It is often mixed with other chemicals, such as resorcinol, to achieve a particular dye color.

p-Phenylenediamine is used as an ingredient of oxidative hair coloring products at a maximal concentration of 4.0%, which, after mixing in a 1:1 ratio with hydrogen peroxide prior to use, corresponds to a maximal concentration of 2.0% at application to the hair.

Safety

p-Phenylenediamine is primarily used as a dye intermediate and as a dye. Acute (short-term) exposure to high levels of p-phenylenediamine may cause severe dermatitis, eye irritation and tearing, asthma, gastritis, renal failure, vertigo, tremors, convulsions, and coma in humans. Eczematoid contact dermatitis may result from chronic (long-term) exposure in humans. In rats and mice chronically exposed to p- phenylenediamine in their diet, depressed body weights but no other clinical signs of toxicity were observed in several studies. No information on the reproductive, developmental, or carcinogenic effects of p-phenylenediamine in humans is available. EPA has not classified p-phenylenediamine with respect to carcinogenicity.

References

[1] Ming Zhang. “Association of p-phenylenediamine exposure with alterations of pulmonary function, pruritus and health-related quality of life in hair dye factory workers: a cross-sectional study.” Scientific Reports 13 1 (2023): 2623.

[2] Enayatollah Seydi. “The effects of para-phenylenediamine (PPD) on the skin fibroblast cells.” Xenobiotica 49 10 (2019): 1143–1148.

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