Organic pigments, self-heating

8 Nitrates of diazonium compounds Organic pigments, self-heating, 4.2 

There are over 8000 chemicals that exhibit commercially significant optical properties. Some of these are natural products such as indigo, chlorophyll, and cochineal, but the majority are synthesized in a series of steps involving dye intermediates (any of the 3000 or more organic and inorganic chemicals used as raw material precursors to manufactured dyes, the most important of which are benzene and naphthalene). Coal tar dyes refers to the dyestuffs originating from the complex mix of hydrocarbons (benzene, toluene, xylene, pyrene, naphthalene, anthracene, etc.) present in coal tar (8007-45-2). Petroleum has succeeded coal as the dominant source of dye intermediates. Dyes, pigments, and dye intermediates include 

Diazonium salts are formed by the diazotization reaction, the action of nitrous acid on primary aromatic amines in the presence of a mineral acid. As salts, these compounds are able to stabilize the reactive azo group in preparation for making dyes and other products. Nitrates of diazonium compounds are diazonium nitrate salts. 

Dyes and pigments and the many chemicals associated with them (e.g., intermediates, dispersants, carriers, etc.) may exhibit any number of hazardous properties. 

Self-heating, see Spontaneously Combustible Materials and Division 4.2 p.226 Solid, see Terminology, Solid, p.247 Toxic, see Toxic Substances and Division 6.1, p.255 

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