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| P-Phenylenediamine | |
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| IUPAC name | 1,4-diaminobenzene |
| Identifiers | |
| CAS number | [106-50-3] |
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| InChI |
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| Properties | |
| Molecular formula | C6H8N2 |
| Molar mass | 108.1 |
| Appearance | Tan solid |
| Melting point |
143-145 °C |
| Boiling point |
267 °C |
| Hazards | |
| R-phrases | R23 R24 R25 R36 R37 R38 R40 R42 R43 |
| S-phrases | S26 S36 S37 S39 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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p-Phenylenediamine (PPD), also called paraphenylenediamine, 1,4-diaminobenzene or 1,4-phenylenediamine is an aromatic amine used as a component of engineering polymers and composites, aramid fibers, hair dyes, rubber chemicals, textile dyes, and pigments. PPD is selected because of its high temperature stability, high strength, and chemical and electrical resistance. However, it is a strong potential carcinogen, which makes it a controversial chemical to be included in hair dyes.
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Uses
This product is added to real henna to create so called "Black Henna," which, in many cases, causes allergic reaction, and can cause scarring in some people. PPD should never be applied directly to the skin in its pure form or mixed with anything else. [1]
This compound is used in almost every hair dye on the market, regardless of brand. The darker the colour, usually, the higher the concentrations. Even the so-called "natural" and "herbal" hair colours, while ammonia-free, contain PPD. Some products sold as henna have PPD added, particularly "black henna." Using body art-quality (BAQ) pure henna, or indigo, is the only way to avoid PPD in hair dye.
Contact allergen
The CDC lists p-phenylenediamine as being a contact allergen. The NIOSH Pocket Guide to Chemical Hazards lists exposure routes as being through inhalation, skin absorption, ingestion, and skin and/or eye contact; symptoms of exposure include throat irritation (pharynx and larynx), bronchial asthma, and sensitization dermatitis. Sensitization is a lifelong issue, which may lead to active sensitization to products including, but not limited to:
- black clothing
- printer ink
- facsimile ink
- hair dye
- fur dye
- leather dye
- photographic products.
One maker of this product states explicitly that p-phenylenediamine should not be used directly on the skin,citation needed however, they admit that other manufacturers of PPD may or may not warn the same.
Misconception
Some misinformation twists have led to PPD's being described as a black mineral from the banks of the River Nile. This gives PPD an undeserved distinction as being both natural and exotic, which it is not.
External links
- NIOSH International Chemical Safety Card for p-Phenylenediamine (PPD)
- NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) entry for p-Phenylenediamine (PPD)
- Du Pont technical data sheet and sales policy for p-Phenylenediamine (PPD)
