Intermediates: Dyeing (pigment) intermediates is an extremely important branch of the fine chemical industry. The development of the supporting intermediates. China's production of intermediates for dyeing and pigment has been developed considerably since 1950s. In the past few years, the production of intermediates of dye and pigment has become more and more fierce, and there have been innovations in production technology. We have made breakthroughs in several areas, such as research, new uses for old varieties and environmental protection, and have adopted a clean process for the production of dye and pigment intermediates. .

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Development of the use of intermediates

In fact, the use of intermediates is multifaceted development, a certain kind of intermediates used in dyes called dye intermediates, and used in pesticides, pharmaceuticals, and so on. Also called pesticide, pharmaceutical intermediates. Should be considered as a branch of the fine chemical industry as a whole, should not be rigidly divided into dye intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates, pesticide intermediates Intermediates, pharmaceutical intermediates, which will reduce the range of uses of some intermediates and affect their development.

Fine chemical intermediates research is characterized by a wide variety, except for a few varieties of production scale is particularly huge, most varieties of tonnage are Not very large, but the preparation process is often more complex, involving many unit reactions and separations, and the production of considerable amounts of The "three wastes" need to be properly handled. Therefore, we should engage in serial product process research, a reasonable organization of intermediates to obtain good scale production efficiency.

From the foreign situation, the research and production of intermediates tend to be properly concentrated to achieve serial production. a few to a dozen varieties of intermediates, such research and production is easier to implement through overall development and adoption of new technologies. We will get twice the result with half the effort. We can refer to the situation in Japan, where the production of intermediates used to be very decentralized, starting from the 1960s. It has been adjusted and concentrated seven times.

Through transformation and development, China's dye and pigment intermediates industry has reached a higher level in terms of production scale, technology and equipment level, which can not only meet the needs of domestic dye and pigment industry development, but also provide more quality intermediates products for foreign countries.

The raw materials required for synthesizing intermediates are mainly obtained from the products of petroleum and coking chemical industry, most of which are benzene, naphthalene, naphthalene, and naphthalene. In recent years, the organic pigments prepared from heterocyclic intermediates have been on the rise. In addition, phenanthrene, pyridine, oxygen fluorene, quinoline, indole, carbazole, biphenyl series compounds, these complex raw materials applied to the manufacture of dyestuff. The use of synthetic raw materials will become more widespread and common.

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The most common chemical reactions used for intermediates

The most common chemical reactions used to process raw materials into intermediates for the dyeing (pigment) industry are as follows.

(1) Sulfonation reaction
(2) Nitrification reactions
(3) Halogenation reactions
(4) Reduction reaction to prepare amino
(5) Diazotization reactions (often accompanied by coupling reactions)
(6) Substitution of sulfonic acid groups into hydroxyl groups by alkali-melting reactions
(7) Acetylation reactions
(8) Oxidation reactions
(9) Condensation and carbonation reactions
(10) Aromatization reactions (mainly amino)
(11) Interchangeable reactions of hydroxyl and amino groups
(12) Hydroxylation of hydroxyl or amino groups

According to the aromatic ring structure of the fine chemical intermediates, they can be classified into aliphatic, benzene, naphthalene, anthraquinone, heterocyclic and dense. Ring system. Our country can produce more than 400 varieties of benzene, naphthalene, anthraquinone, heterocyclic and other intermediates of dyeing and pigment, which can basically meet the requirements of the Dyeing and pigment industry development needs.

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Major varieties of benzene system

2,4-Dinitrochlorobenzene, o-nitrochlorobenzene, p-nitrochlorobenzene, p-nitrophenol, N,N-dimethylaniline, p-amino Anisole, p-nitroaniline, o-toluidine, 2-bromo-6-chloro-p-nitroaniline, N-ethylaniline, m-hydroxydiethylaniline 2,4-dinitro-6-bromoaniline, o-, p-phenylenediamine, 3,3-dichlorobenzidine, benzidine, anisylamine, p-amine Benzenesulfonic acid, o-anisole, p-aminoanisole, DSD acid, p-aminophenetole, CTL acid, o-cyano-p-nitroaniline, acetoacetylacetamide o-Methoxyaniline, hydroquinone, resorcinol, N-methyl-m-toluidine, N-ethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethyl-m-toluidine Toluidine, N,N-diethyl-m-toluidine, N-methyl-hydroxyethyl-m-toluidine, N-ethyl-hydroxyethyl-m-toluidine, N-ethyl-toluidine Methyl cyanoethyl-m-toluidine, N-ethyl cyanoethyl-m-toluidine, N-methylphenyl-m-toluidine, p-, ethoxyaniline, 2 4-dimethylaniline, 4-chloro-3-aminobenzamide, 4-methyl-3-aminobenzamide, 4-methoxy-3-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide, 4-methyl-aminobenzamide 2,4,5-Trichloroaniline, 4-methoxy-3-amino-N,N-diethylbenzenesulfonamide, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline, 2,4,5-trichloroaniline inter, para ester, etc.

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Main varieties of naphthalene intermediates

2-naphthol, H-acid, K-acid, 2,3-acid, 2,6-acid, thujaplic acid, 6-nitro-1,2,4 acid oxygens. J-acid, peri-acid, gamma-acid, G-salt, R-salt, amino K-acid, 2-naphthylamine-1,5-disulfonic acid, 1-naphthol -5-sulfonic acid, 1,5-dihydroxynaphthalene, 2,6-naphthalenedicarboxylic acid, 2R-acid and so on. Anthraquinone intermediates include: anthraquinone, 1-amino anthraquinone, 1,4-diamino anthraquinone, 1,5-dimethyl-bromophosphate, 1,5-dimethyl-anthraquinone, 2,6-naphthalenedicarboxylic acid, 2R-acid, etc. Anthraquinone, 1,5-diamino anthraquinone, 1-Amino-5-benzoyl anthraquinone, 1,5-dihydroxyanthraquinone, 1,8-hydroxy Anthraquinone, 1,8-dihydroxy-4,5-diamino anthraquinone, etc.

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Major heterocyclic and dense-cyclic species

Cyanuric chloride, barbituric acid, 2-amino-6-nitrobenzothiazole, 2-amino-5,6-dichlorobenzothiazole, 2-aminobenzothiazole Aminothiazole, dehydrothiobenzidine bisulfonic acid, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone, 3-cyano-4-methyl-6-hydroxy-N-ethylpyridone Formylamino-4-methyl-6-hydroxy-N-ethylpyridone, 4-chloro-1,8-naphthalene anhydride, naphthalene tetracarboxylic anhydride, ! tetracarboxylic anhydride, etc.