Para-Phenylenediamine

Para-Phenylenediamine

 

(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.