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.
Hydrazones are a class of organic compounds with the structure R1R2C=N−NH2. They are related to ketones and aldehydes by the replacement of the oxygen =O with the =N−NH2 functional group. They are formed usually by the action of hydrazine on ketones or aldehydes.
Cadmium pigments are a class of pigments that contain cadmium. Most of the cadmium produced worldwide has been for use in rechargeable nickel–cadmium batteries, which have been replaced by other rechargeable nickel-chemistry cell varieties such as NiMH cells, but about half of the remaining consumption of cadmium, which is approximately 2,000 tonnes annually, is used to produce colored cadmium pigments. The principal pigments are a family of yellow, orange and red cadmium sulfides and sulfoselenides, as well as compounds with other metals.
Cadmium sulfide is the inorganic compound with the formula CdS. Cadmium sulfide is a yellow salt. It occurs in nature with two different crystal structures as the rare minerals greenockite and hawleyite, but is more prevalent as an impurity substituent in the similarly structured zinc ores sphalerite and wurtzite, which are the major economic sources of cadmium. As a compound that is easy to isolate and purify, it is the principal source of cadmium for all commercial applications. Its vivid yellow color led to its adoption as a pigment for the yellow paint "cadmium yellow" in the 1800s.
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.
Indian yellow is a complex pigment consisting primarily of euxanthic acid salts, euxanthone and sulphonated euxanthone. It is also known as purree, snowshoe yellow, gaugoli, gogili, Hardwari peori, Monghyr puri, peoli, peori, peri rung, pioury, piuri, purrea arabica, pwree, jaune indien, Indischgelb (German), yìndù huáng (Chinese), giallo indiano (Italian), amarillo indio (Spanish).
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.
Phenazine is an organic compound with the formula (C6H4)2N2. It is a dibenzo annulated pyrazine, and the parent substance of many dyestuffs, such as the toluylene red, indulines, and safranines (and the closely related eurhodines). Phenazine crystallizes in yellow needles, which are only sparingly soluble in alcohol. Sulfuric acid dissolves it, forming a deep-red solution.
Aniline Yellow is a yellow azo dye and an aromatic amine. It is a derivative of azobenzene. It has the appearance of an orange powder. Aniline Yellow was the first azo dye. it was first produced in 1861 by C. Mene. The second azo dye was Bismarck Brown in 1863. Aniline Yellow was commercialized in 1864 as the first commercial azo dye, a year after aniline black. It is manufactured from aniline.
Pyrazolone is 5-membered heterocycle containing two adjacent nitrogen atoms. It can be viewed as a derivative of pyrazole possessing an additional carbonyl (C=O) group. Compounds containing this functional group are useful commercially in analgesics and dyes.
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.
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.
Diketene is an organic compound with the molecular formula C4H4O2, and which is sometimes written as (CH2CO)2. It is formed by dimerization of ketene, H2C=C=O. Diketene is a member of the oxetane family. It is used as a reagent in organic chemistry. It is a colorless liquid.
Pigment Yellow 83 is an organic compound that is classified as a diarylide pigment. It is used as a yellow colorant.
Pigment Yellow 12 is an organic compound and an azo compound. It is a widely used yellow pigment. It is also classified as a diarylide pigment, being derived from 3,3'-dichlorobenzidine. It is closely related to Pigment Yellow 13, wherein the two phenyl groups are replaced by 2,4-xylyl. According to X-ray crystallography, the molecule is nearly planar and exists as the keto-hydrazide tautomer.
Pigment Yellow 13 is an organic compound and an azo compound. It is a widely used yellow pigment. It is also classified as a diarylide pigment, being derived from 3,3'-dichlorobenzidine. It is closely related to Pigment Yellow 12, wherein the two xylyl groups are replaced by phenyl. It is often depicted as an azo (-N=N-) structure, but according to X-ray crystallography closely related compounds exist as the keto-hydrazide tautomers.
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.
Pigment Yellow 74 is an azo dye and classified as an arylide yellow. It is an intensely yellow-green solid. It is prepared by azo coupling of the diazonium derivative of 2-methoxy-4-nitroaniline with 2-methoxyacetoacetanilide. It is a flat molecule, enforced by the hydrogen-bonding via the ketohydrazide group.
