P-Phenylenediamine

Chembox new
ImageFile = P-phenylenediamine.png ImageSize =
IUPACName = 1,4-diaminobenzene
OtherNames =
Section1 = Chembox Identifiers
CASNo = 106-50-3
PubChem =
SMILES = Nc1ccc(N)cc1
InChI=1/C6H8N2/c7-5-1-2-6 (8)4-3-5/h1-4H,7-8H2
Section2 = Chembox Properties
Formula = C₆H₈N₂
MolarMass = 108.1
Appearance = Tan solid
Density =
MeltingPt = 143-145 °C
BoilingPt = 267 °C
Solubility =
Section3 = Chembox Hazards
MainHazards =
FlashPt =
Autoignition =
RPhrases = R23 R24 R25 R36 R37 R38 R40 R42 R43
SPhrases = S26 S36 S37 S39 lowercase|p-Phenylenediamine

"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.

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. [http://www.hennapage.com/henna/ppd/smallbroch1.pdf]

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.

However, when tested (http://www.epa.gov/ttn/atw/hlthef/phenylen.html) by the United States Environmental Protection Agency, the EPA reports that in rats and mice chronically exposed to p-phenylenediamine in their diet, it simply depressed body weights, but there were no other clinical signs of toxicity, as were observed in several studies. No information is available on the reproductive, developmental, or carcinogenic effects of p-phenylenediamine in humans. In fact, the EPA has not classified p-phenylenediamine with respect to carcinogenicity. Therefore, it has not been deemed an actual carcinogen.

"p"-Phenylenediamine is used in the manufacture of aramid plastics and fibers such as Kevlar as well as substituted "p"-phenylenediamines that are used as antiozonants in rubber.

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,Fact|date=February 2007 however, they admit that other manufacturers of PPD may or may not warn the same.

Misconception

Some misinformation twists have led to PPDs being described as a black mineral from the banks of the River NileFact|date=September 2008. This gives PPD an undeserved distinction as being both natural and exotic, which it is not.

External links

* [http://www.cdc.gov/niosh/ipcsneng/neng0805.html NIOSH International Chemical Safety Card for p-Phenylenediamine (PPD)]
* [http://www.cdc.gov/niosh/rtecs/ss7ad550.html NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) entry for p-Phenylenediamine (PPD)]
* [http://www.dupont.com/specintermediates/ppd.html Du Pont technical data sheet and sales policy for p-Phenylenediamine (PPD)]