The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



(p-diaminobenzene), an organic compound, the para isomer of phenylenediamine. Colorless crystals that darken on exposure to light and air. Melting point, 147°C; boiling point, 267°C. The chemical structure of para-phenylenediamine is

A strong reducing agent, para-phenylenediamine quickly oxidizes upon exposure to atmospheric oxygen. It is readily soluble in alcohol and ether, and 1 g dissolves in 100 g of cold water. The substance is obtained by reducing para-nitroaniline or aminoazobenzene and interacts with mineral acids to form salts.

Para-phenylenediamine is used as a microgranular developer in black-and-white photography; the N, N-dialkyl derivatives of para-phenylenediamine, which are more active, are the most widely used developers in color photography. Para-phenylenediamine is also used in the synthesis of many organic dyes and in analytical chemistry. The compound is a strong skin irritant, and its N,N-dialkyl derivatives produce a milder degree of irritation.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Repeated topical application of para-phenylenediamine induces renal histopathological changes in rats.
These are followed by the metal cobalt (6%); the preservatives quaternium 15 and formaldehyde (both 6%); para-phenylenediamine, also known as PPD, which is used in hair dye (5%); and the fragrance mix II (5%), another mix of fragrances used in allergen testing.
Yet with black henna, a substance called para-phenylenediamine is used, which is typically found in hair dyes but is not used in normal henna tattoos.
Systemic toxicity of para-phenylenediamine. Lancet.
According to TEM images in Figures 10(c) and 10(d), the coating layer was 15~25nm, but a single para-phenylenediamine molecule is about 1 nm in length.
The reference chemicals were: isopropanol (67-63-0); salicylic acid (69-72-7); lactic acid (50-21-5); glycerol (56-81-5); 4-methoxy-acetophenone (100-06-1) chlorobenzene (108-90-7); methyl salicylate (119-36-8); sulfanilamide (63-74-1); ethylene glycol dimethacrylate (97-90-5); phenyl benzoate (93-99-2); eugenol (97-53-0); 2-mercaptobenzothiazole (149-30-4); citral (5392-40-5); isoeugenol (97-54-1); methyldibromo glutaronitrile (35691-65-7); 4-methylaminophenol sulphate (55-55-0); para-phenylenediamine (106-50-3); 2,4-dinitrochlorobenzene (97-00-7); 4-nitrobenzylbromide (100-11-8); oxazolone (15646-46-5); cinnamyl alcohol (104-54-1).
But, unknown to Chloe, her tattoo was done with black henna, which contains a substance called para-phenylenediamine, typically found in hair dyes.
Doctors have warned that the majority of black henna tattoos are made using a substance called para-phenylenediamine, which is found in hair dyes.
Key statement: Rubber composition which can be used in particular for the manufacture of tires, comprising at least a diene elastomer, a reinforcing filler, a crosslinking system, between 0.2 and 10 phr of an antioxidant, such as a substituted para-phenylenediamine, and between 0.2 and 10 phr of an acetylacetonate of an alkali metal or alkaline earth metal, chosen in particular from the group consisting of Li, Na, K, Mg, Ca and the mixtures of such metals.
Often inkings are not henna at all, but a dye called para-phenylenediamine, which can cause blistering and burns.