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In chemistry, amines are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines, trimethylamine, and aniline; see Category:Amines for a list of amines. Inorganic derivatives of ammonia are also called amines, such as monochloramine.
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.
Organic chemistry is a branch of chemistry that studies the structure, properties and reactions of organic compounds, which contain carbon-carbon covalent bonds. Study of structure determines their structural formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior. The study of organic reactions includes the chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical study.
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.
The quinones are a class of organic compounds that are formally "derived from aromatic compounds [such as benzene or naphthalene] by conversion of an even number of –CH= groups into –C(=O)– groups with any necessary rearrangement of double bonds, resulting in "a fully conjugated cyclic dione structure". The archetypical member of the class is 1,4-benzoquinone or cyclohexadienedione, often called simply "quinone". Other important examples are 1,2-benzoquinone (ortho-quinone), 1,4-naphthoquinone and 9,10-anthraquinone.
Azo compounds are compounds bearing the functional group diazenyl.
The diazogroup is an organic moiety consisting of two linked nitrogen atoms (azo) at the terminal position. Overall charge neutral organic compounds containing the diazo group bound to a carbon atom are called diazo compounds or diazoalkanes and are described by the general structural formula R2C=N+=N–. The simplest example of a diazo compound is diazomethane, CH2N2. Diazo compounds (R2C=N2) should not be confused with azo compounds of the type R-N=N-R or with diazonium compounds of the type R-N2+.
Sudan I, is an organic compound, typically classified as an azo dye. It is an intensely orange-red solid that is added to colourise waxes, oils, petrol, solvents, and polishes. Sudan I has also been adopted for colouring various foodstuffs, especially curry powder and chili powder, although the use of Sudan I in foods is now banned in many countries, because Sudan I, Sudan III, and Sudan IV have been classified as category 3 carcinogens by the International Agency for Research on Cancer. Sudan I is still used in some orange-coloured smoke formulations and as a colouring for cotton refuse used in chemistry experiments.
Acid dyes are anionic, soluble in water and are essentially applied from acidic bath. These dyes possess acidic groups, such as SO3H and COOH and are applied on wool, silk and nylon when ionic bond is established between protonated –NH2 group of fibre and acid group of dye. Overall wash fastness is poor although lightfastness is quite good. As dye and fibre contain opposite electrical nature, strike rate and uptake of acid dye on these fibres is faster; electrolyte at higher concentration is added to retard dye uptake and to form levelled shades. Acid generates cation on fibre and temperature helps to substitute negative part of acid with anionic dye molecules.
Organic reductions or organic oxidations or organic redox reactions are redox reactions that take place with organic compounds. In organic chemistry oxidations and reductions are different from ordinary redox reactions, because many reactions carry the name but do not actually involve electron transfer in the electrochemical sense of the word. Instead the relevant criterion for organic oxidation is gain of oxygen and/or loss of hydrogen, respectively.
Azo dyes are organic compounds bearing the functional group R−N=N−R′, in which R and R′ are usually aryl. They are a commercially important family of azo compounds, i.e. compounds containing the linkage C-N=N-C. Azo dyes are widely used to treat textiles, leather articles, and some foods. Chemically related to azo dyes are azo pigments, which are insoluble in water and other solvents.
Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group [R−N+≡N]X− where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halide.
In organic chemistry, an azo coupling is an organic 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 arene is a nucleophile. In most cases, including the examples below, the diazonium compound is also aromatic.
Ethylenediamine (abbreviated as en when a ligand) is the organic compound with the formula C2H4(NH2)2. This colorless liquid with an ammonia-like odor is a basic amine. It is a widely used building block in chemical synthesis, with approximately 500,000 tonnes produced in 1998. Ethylenediamine is the first member of the so-called polyethylene amines.
Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include naturally occurring chemicals, such as in plants and insects, as well as synthetics such as polybutyrate. Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not. Synthetic polyesters are used extensively in clothing.
Pyrylium is a cation with formula C5H5O+, consisting of a six-membered ring of five carbon atoms, each with one hydrogen atom, and one positively charged oxygen atom. The bonds in the ring are conjugated as in benzene, giving it an aromatic character. In particular, because of the positive charge, the oxygen atom is trivalent. Pyrilium is a mono-cyclic and heterocyclic compound, one of the oxonium ions.
The reduction of nitro compounds are chemical reactions of wide interest in organic chemistry. The conversion can be effected by many reagents. The nitro group was one of the first functional groups to be reduced. Alkyl and aryl nitro compounds behave differently. Most useful is the reduction of aryl nitro compounds.
2-Tolidine (orthotolidine, o-tolidine; not to be confused with o-toluidine) is an organic compound with the chemical formula (C6H4(CH3)NH2)2. Several isomers are known; the 3-tolidine derivative is also important commercially. It is a colorless compound although commercial samples are often colored. It is slightly soluble in water. It forms salts with acids, such as the hydrochloride, which is commercially available.
o-Dianisidine is an organic compound with the formula [(CH3O)(H2N)C6H3]2. A colorless or white solid, it is a bifunctional compound derived via the benzidine rearrangement from o-anisidine.
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.
References
- ↑ P.F. Vogt, J.J. Gerulis (2005). "Amines, Aromatic". Ullmann’s Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a02_037.
- An acute case of primary aromatic amines migrating from cooking utensils [ permanent dead link ], Memorandum for the Danish Veterinary and Food Administration, 2004 October 12
