Azo dye
Water-insoluble organic compounds containing azo group (-n =N-) in molecular structure are the most diverse and productive organic pigments. Azo pigments are diazo components produced by aromatic amine or heteraramine by diazotization and then coupled with acetyaramine, 2-naphthol, pyrazolone, 2-hydroxy-3-naphthol formic acid or 2-hydroxy-3-naphthol formamide and other coupling components, to produce water insoluble precipitation, that is, the general azo pigments. Its synthetic method is basically the same as azo dye, but the latter is water-soluble. Common azo pigments are orange, yellow and red pigments such as permanent orange. Pigment orange 5), golden red (C.I. pigment red 21), benzidine yellow G(C.I. Pigment yellow 12). In order to improve the properties of pigments such as sun-resistant, heat-resistant and organic solvent resistant, two molecules can be condensed into macromolecules by aromatic diamine. Pigments made in this way are called macromolecular pigments or condensed azo pigments such as macromolecular orange 4R. Pigment orange 31), macromolecule red R(C.I. pigment red 166).
lake
A water-soluble pigment produced by the action of a precipitant with water-soluble dyes, such as acid, direct, or basic dyes. Its color is more brilliant, chromatogram is more complete, production cost is low, than the original water-soluble dye fastness to the sun. The precipitants are mainly inorganic salts, acids, carriers and so on. Inorganic salt precipitation is the reaction between barium chloride, calcium chloride, manganese sulfate and other water-soluble dyes to produce water-insoluble barium, calcium, manganese and other salts such as permanent red F5R(C.I. Pigment red 48:2), golden red C(C.I. pigment red 53:1). Acid precipitation USES phosphoric acid molybdic acid, phosphotungstic acid, tannic acid and other as precipitants to react with water-soluble basic dyes to produce insoluble lakes such as sunfast rose lake (C.I). Pigment violet 1), pigment violet 3 (C.I. pigment violet 3). Carrier precipitation is the deposition of water-soluble dyes on the surface of carriers such as aluminum hydroxide and barium sulfate to form water-insoluble lakes such as acidic golden lake (C.I). Pigment orange 17), fast sun lake Blue Lake (C.I. pigment blue 17).
Phthalocyanine pigment
The main body of the molecule is phthalocyanine, and the structural formula is:
They are water-insoluble organic compounds and are predominantly blue and green pigments. In 1934, the first variety, Phthalocyanine blue, was produced by The British Chemical Industry Company and the German French Company. The vast majority of products contain divalent metals, such as copper, nickel, iron, manganese, etc., but also replace the benzene ring in the molecule with pyrrole ring or other rings, other groups are also introduced in the molecule, different structures have different properties and USES. The main variety of phthalocyanine pigments is copper containing phthalocyanine blue (C.I. pigment blue 15). The main industrial production method is the reaction of phthalic anhydride with urea (or phthalonitrile directly) with cuprous chloride in the presence of ammonium molybdate catalyst, and the resulting crude product is commonly known as "copper phthalocyanine". Different commodities can be obtained by different methods of pigment post-treatment. If the crude substance is dissolved in concentrated sulfuric acid and then slowly precipitated in water, alpha crystal, a blue organic pigment with red light, can be obtained. If the crude product is dissolved in concentrated sulfuric acid, and then a small amount of chlorine gas, so that there are 1 to 2 chlorine atoms on the molecule, the color of the product is more green than without chlorine; If the crude products and dry sodium chloride grinding in the ball mill, you can get a stable green crystal products. The crude product is heated to about 220°C in aluminum trichloride and sodium chloride melt, and chlorine gas is introduced into the molecule to introduce 14~16 chlorine atoms, then the product is bright green pigment. If a small amount of bromine is introduced, the color of the product will be more yellow and bright.
Quinacridone pigment
The basic structure of the molecule is the pigment of quinacridone:
Dupont began production in 1958. The production method is that diethyl succinate is condensed by itself, condensed with aniline, closed loop, refined and oxidized to obtain crystalline quinacridone pigment. Because of its heat resistance, light resistance, brightness and other properties similar to phthalocyanine pigments, the commodity is called phthalocyanine red (C.I. The color purple 19), in fact, the two molecules are completely different. If different conditions are used for oxidation, then the color of the more blue crystal quinacridone pigment, known as the commercial phthalocyanine purple.
In addition to the above varieties, there are also some varieties with good performance, such as dioxazine pigments, represented by permanent violet RL(ci.). The purple pigment 23); Isoindolinone pigment, represented by pigment yellow 2GLT(C.I. pigment yellow 109); Benzimidazolone pigment, represented by permanent orange HSL(C.I. pigment Orange 36).
The research focus of organic pigment workers is on the improvement of pigment post-treatment, such as choosing better crystal type, making fine particles with narrow particle size distribution, improving the wettability of pigment, etc., so that organic pigment can play a greater role.
Organic dye English name :organic dye