Introduction of Dye Intermediates

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Introduction of Dye Intermediates

Dye intermediates also called intermediate, refers to the various aromatic derivatives used in the production of dyes and organic pigments. They are from coal chemical and petrochemical of benzene, toluene, naphthalene and aromatic hydrocarbons such as anthracene as raw materials, through a series of unit processes in organic synthesis (see reactions). With the development of the chemical industry, dyestuff intermediate range of applications has been extended to the pharmaceutical industry, pesticide industry, explosives industry, information recording materials industries, as well as additives, surfactants, perfumes, plastics, synthetic fibers and other production sectors. Dye intermediates in many varieties, the more important there are hundreds of species. The most important dye intermediate such as nitrobenzene and aniline, phenol and chlorobenzene and phthalic anhydride, wide usage, dosage, have resulted in important basic organic intermediate, annual production inthe world are the million tons. Now the most important dye intermediate o-chloro-, p-dichlorobenzene, o-nitrotoluene, p-toluene, 2-naphthol, Anthraquinone, 1-amino Anthraquinone. Leaving from these intermediates, through a series of unit processes of organic synthesis, and can produce all kinds of complex structures of intermediates.

Dye intermediates for dye intermediates chemicals include benzene intermediates,toluene is intermediate, intermediate four groups intermediates of naphthalene and anthracene Quinone, in addition, there are other heterocyclic intermediate. Production of reactive intermediates used primarily with nitrification, sulfonation, halogenation, amination, hydrolysis, reduction, oxidation, such as condensation. Intermediates for synthesis of a more complex structure, often after many cell processes,sometimes using different raw materials and different synthetic routes. For example, the production of p-nitroaniline, initially with benzene nitration, reduction with aniline, acylation, Nitration, hydrolysis of synthetic routes, this production process is long and expensive. Now use chlorination, nitration of benzene, separation of nitrochlorobenzene and high pressure ammonia synthesis routes. Dedicated intermediates used in manufacturing dyes, pesticides or pharmaceuticals, often complex structures, and supporting the production of the final product, production is small, producing intermittent operation. Versatile intermediates, such as nitrobenzene andaniline, chlorobenzene, phenol, etc, usually integrated in a large chemical plant production, production, production of continuous operation.