A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and may require a mordant to improve the fastness of the dye on the fiber.
Magenta is a purplish-red color. On color wheels of the RGB (additive) and CMY (subtractive) color models, it is located precisely midway between blue and red. It is one of the four colors of ink used in color printing by an inkjet printer, along with yellow, cyan, and black to make all the other colors. The tone of magenta used in printing, printer's magenta, is redder than the magenta of the RGB (additive) model, the former being closer to rose.
A pigment is a powder used to add color or change visual appearance. Pigments are completely or nearly insoluble and chemically unreactive in water or another medium; in contrast, dyes are colored substances which are soluble or go into solution at some stage in their use. Dyes are often organic compounds whereas pigments are often inorganic. Pigments of prehistoric and historic value include ochre, charcoal, and lapis lazuli.
Aniline is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile starting material for fine chemical synthesis. Its main use is in the manufacture of precursors to polyurethane, dyes, and other industrial chemicals. Like most volatile amines, it has the odor of rotten fish. It ignites readily, burning with a smoky flame characteristic of aromatic compounds. It is toxic to humans.
Azo compounds are organic compounds bearing the functional group diazenyl.
Sudan I is an organic compound typically classified as an azo dye. It is an orange-red solid, used to color waxes, oils, petrol, solvents, and polishes. Historically, Sudan I used to serve as a food coloring agent, notably for curry powder and chili powder. However, along with its derivatives Sudan III and Sudan IV, the compound has been banned in many countries due to its classification as a category 3 carcinogenic hazard by the International Agency for Research on Cancer. Nevertheless, Sudan I remains valuable as a coloring reagent for non-food-related uses, such as in the formulation of orange-colored smoke.
An acid dye is a dye that is typically applied to a textile at low pH. They are mainly used to dye wool, not cotton fabrics. Some acid dyes are used as food colorants, and some can also be used to stain organelles in the medical field.
Azo dyes are organic compounds bearing the functional group R−N=N−R′, in which R and R′ are usually aryl and substituted aryl groups. They are a commercially important family of azo compounds, i.e. compounds containing the C-N=N-C linkage. Azo dyes are synthetic dyes and do not occur naturally. Most azo dyes contain only one azo group but there are some that contain two or three azo groups, called "diazo dyes" and "triazo dyes" respectively. Azo dyes comprise 60-70% of all dyes used in food and textile industries. Azo dyes are widely used to treat textiles, leather articles, and some foods. Chemically related derivatives of azo dyes include azo pigments, which are insoluble in water and other solvents.
In organic chemistry, an azo coupling is an reaction between a diazonium compound and another aromatic compound that produces an azo compound. In this electrophilic aromatic substitution reaction, the aryldiazonium cation is the electrophile, and the activated carbon, serves as a nucleophile. Classical coupling agents are phenols and naphthols. Usually the diazonium reagent attacks at the para position of the coupling agent. When the para position is occupied, coupling occurs at a ortho position, albeit at a slower rate.
Red 2G is a synthetic red azo dye. It is soluble in water and slightly soluble in glycerol. It usually comes as a disodium salt of 8-acetamido-1-hydroxy-2-phenylazonaphthalene-3,6 disulfonate.
Sudan Yellow 3G, also known as Solvent Yellow 16, C.I. disperse yellow and C.I. 12700, is a yellow azo dye. It is soluble in fats and oils.
Solvent Yellow 56 is the organic compound N,N-diethyl-p-(phenylazo)aniline. It is an azo dye, which has the appearance of a reddish yellow powder. Its EINECS number is 219-616-8. Its structure is similar to Solvent Yellow 124, which used as a fuel dye in European Union, and to Aniline Yellow.
In staining dyes, nigrosin is a mixture of black synthetic dyes made by heating a mixture of nitrobenzene, aniline, and hydrochloric acid in the presence of copper or iron. Related to induline, it is a mixture of phenazine-based compounds. Its main industrial uses are as a colorant for lacquers and varnishes and in marker pen inks. Sulfonation of nigrosin yields a water-soluble anionic dye, nigrosin WS.
Arylide yellow, also known as Hansa yellow and monoazo yellow, is a family of organic compounds used as pigments. They are primarily used as industrial colorants including plastics, building paints and inks. They are also used in artistic oil paints, acrylics and watercolors. These pigments are usually semi-transparent and range from orange-yellow to yellow-greens. Related organic pigments are the diarylide pigments. Overall, these pigments have partially displaced the toxic cadmium yellow in the marketplace. Painters such as Alexander Calder and Jackson Pollock are known to have employed arylide yellow in their artworks.
Aniline leather is a type of leather dyed exclusively with soluble dyes. The dye colours the leather without producing the uniform surface of a topcoat paint or insoluble pigmented sealant, as on other leathers, and so retains the hide's natural surface. Hence, any visible variations on the surface of the undyed leather such as visible pores, scars, or other blemishes will remain visible. For this reason, only high-quality leather is suitable for aniline finishing.
Tattoo inks consist of pigments combined with a carrier, used in the process of tattooing to create a tattoo in the skin. These inks are also used for permanent makeup, a form of tattoo.
2,4-Dinitroaniline is a chemical compound with a formula of C6H5N3O4. It is used as an explosive and as a reagent to detect and characterize aldehydes and ketones.
Acetoacetanilide is an organic compound with the formula CH3C(O)CH2C(O)NHC6H5. It is the acetoacetamide derivative of aniline. It is a white solid that is poorly soluble in water. This chemical and many related compounds (prepared from various aniline derivatives) are used in the production of organic pigments called arylide yellows. Acetoacetanilides usually exist as the keto-amide tautomer according to X-ray crystallography.
Basic Red 18 is a cationic azo dye used for coloring textiles. The chromophore is the cation, which contains many functional groups, but most prominently the quaternary ammonium center.
A colorant is any substance that changes the spectral transmittance or reflectance of a material. Synthetic colorants are those created in a laboratory or industrial setting. The production and improvement of colorants was a driver of the early synthetic chemical industry, in fact many of today's largest chemical producers started as dye-works in the late 19th or early 20th centuries, including Bayer AG(1863). Synthetics are extremely attractive for industrial and aesthetic purposes as they have they often achieve higher intensity and color fastness than comparable natural pigments and dyes used since ancient times. Market viable large scale production of dyes occurred nearly simultaneously in the early major producing countries Britain (1857), France (1858), Germany (1858), and Switzerland (1859), and expansion of associated chemical industries followed. The mid-nineteenth century through WWII saw an incredible expansion of the variety and scale of manufacture of synthetic colorants. Synthetic colorants quickly became ubiquitous in everyday life, from clothing to food. This stems from the invention of industrial research and development laboratories in the 1870s, and the new awareness of empirical chemical formulas as targets for synthesis by academic chemists. The dye industry became one of the first instances where directed scientific research lead to new products, and the first where this occurred regularly.
