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Elon (chemical)
Metol is a trade name for the organic compound with the formula OC6H4NH2(CH3)sub>2HSO4. It is the sulfate salt of ''N''-methylaminophenol. This colourless salt is a popular photographic developer used in monochrome photography.Gerd Löbbert "Photography" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. Synthesis and degradation Several methods exist for the preparation of ''N''-methylaminophenol. It arises by decarboxylation of ''N''-4-hydroxyphenylglycine ( Glycin). It can be obtained by reaction of hydroquinone with methylamine. Being an electron-rich arene, metol is readily degraded by hydrogen peroxide. Application Metol is an excellent developing agent for most continuous tone developer applications, and it has been widely used in published developer formulas as well as commercial products. However, it is difficult to produce highly concentrated developer solutions using Metol, and therefore, most Metol developers are supplied in dry chemica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Compound
Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-containing compounds such as alkanes (e.g. methane ) and its derivatives are universally considered organic, but many others are sometimes considered inorganic, such as certain compounds of carbon with nitrogen and oxygen (e.g. cyanide ion , hydrogen cyanide , chloroformic acid , carbon dioxide , and carbonate ion ). Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise the discipline known as organic chemistry. For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts), along with a few other exceptions (e.g., carbon dioxide, and even ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Sulfate
The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many are prepared from that acid. Spelling "Sulfate" is the spelling recommended by IUPAC, but "sulphate" was traditionally used in British English. Structure The sulfate anion consists of a central sulfur atom surrounded by four equivalent oxygen atoms in a tetrahedral arrangement. The symmetry of the isolated anion is the same as that of methane. The sulfur atom is in the +6 oxidation state while the four oxygen atoms are each in the −2 state. The sulfate ion carries an overall charge of −2 and it is the conjugate base of the bisulfate (or hydrogensulfate) ion, , which is in turn the conjugate base of , sulfuric acid. Organic sulfate esters, such as dimethyl sulfate, are covalent compounds and esters of sulfuric acid. The tetrahedra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photographic Developer
In the Photographic processing, processing of photographic films, plates or papers, the photographic developer (or just developer) is one or more chemicals that convert the latent image to a visible image. Developing agents achieve this conversion by Redox, reducing the silver halides, which are pale-colored, into silver metal, which is black when in the form of fine particles.Karlheinz Keller et al. ''Photography'' in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2005, Wiley-VCH, Weinheim. . The conversion occurs within the gelatine matrix. The special feature of photography is that the developer acts more quickly on those particles of silver halide that have been exposed to light. When left in developer, all the silver halides will eventually be reduced and turn black. Generally, the longer a developer is allowed to work, the darker the image. Chemical composition of developers The developer typically consists of a mixture of chemical compounds prepared as an aqueous solut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monochrome Photography
Monochrome photography is photography where each position on an image can record and show a different ''amount'' of light (Value (color), value), but not a different color (hue). The majority of monochrome photographs produced today are black-and-white, either from a gelatin silver process, or as digital photography. Other hues besides grey can be used to create monochrome photography, but brown and Sepia (color), sepia tones are the result of older processes like the albumen print, and cyan tones are the product of cyanotype prints. As monochrome photography provides an inherently less accurate reproduction than color photography, it is mostly used for artistic purposes and certain Imaging, technical imaging applications. Description Although methods for color photography, photographing in color emerged slowly starting in the 1850s, monochrome imagery dominated photography until the mid–twentieth century. From the start, photographic recording processes such as the dague ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycin
Glycin, or N-(4-hydroxyphenyl)glycine, is N-substituted p-aminophenol. It is a photographic developing agent used in classic black-and-white developer solutions. It is not identical to, but derived from glycine, the proteinogenic amino acid. It is typically characterized as thin plates of white or silvery powder, although aged samples appear brown. It is sparingly soluble in water and most organic solvents; it is readily soluble in alkalies and acids.{{cite encyclopedia, last1=Mitchell, first1=Stephen C., last2=Waring, first2=Rosemary H., encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry, publisher=Wiley-VCH, year=2000, doi=10.1002/14356007.a02_099, isbn=978-3527306732, chapter=Aminophenols Glycin is structurally related to 4-aminophenol and metol. Decarboxylation of glycin gives metol. Glycin has a milder reduction potential than metol. The two developers have markedly different character. Glycin is slower-acting, but much longer-lasting in solution. Glycin is rarely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroquinone
Hydroquinone, also known as benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, a derivative of benzene, having the chemical formula C6H4(OH)2. It has two hydroxyl groups bonded to a benzene ring in a ''para'' position. It is a white granular solid. Substituted derivatives of this parent compound are also referred to as hydroquinones. The name "hydroquinone" was coined by Friedrich Wöhler in 1843. In 2022, it was the 268th most commonly prescribed medication in the United States, with more than 900,000 prescriptions. Production Hydroquinone is produced industrially in two main ways.Phillip M. Hudnall "Hydroquinone" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. 2005 Wiley-VCH, Weinheim. . * The most widely used route is similar to the cumene process in reaction mechanism and involves the dialkylation of benzene with propene to give 1,4-diisopropylbenzene. This compound reacts with air to afford the bis(hydrop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylamine
Methylamine, also known as methanamine, is an organic compound with a formula of . This colorless gas is a derivative of ammonia, but with one hydrogen atom being replaced by a methyl group. It is the simplest primary amine. Methylamine is sold as a solution in methanol, ethanol, tetrahydrofuran, or water, or as the anhydrous gas in pressurized metal containers. Industrially, methylamine is transported in its anhydrous form in pressurized railcars and tank trailers. It has a strong odor similar to rotten fish. Methylamine is used as a building block for the synthesis of numerous other commercially available compounds. Industrial production Methylamine has been produced industrially since the 1920s (originally by Commercial Solvents Corporation for dehairing of animal skins). This was made possible by and his wife Eugenia who discovered amination of alcohols, including methanol, on alumina or kaolin catalyst after WWI, filed two patent applications in 1919 and published an a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or "high-test peroxide", decomposes explosively when heated and has been used as both a monopropellant and an oxidizer in rocketry. Hydrogen peroxide is a reactive oxygen species and the simplest peroxide, a compound having an oxygen–oxygen single bond. It decomposes slowly into water and elemental oxygen when exposed to light, and rapidly in the presence of organic or reactive compounds. It is typically stored with a Stabilizer (chemistry), stabilizer in a weakly acidic solution in an opaque bottle. Hydrogen peroxide is found in biological systems including the human body. Enzymes that u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superadditive Developer
Photographic developer solutions may contain more than one developing agents, such as Metol and hydroquinone, or Phenidone and hydroquinone. This is because they work together to a synergistic effect, called superadditive development. Definition Superadditive development commonly means that the mathematical superadditive inequality holds for the rate of development. That is, the rate of development of the two (or more) agents together is greater than the sum of the rate of each agent used alone. There are cases that ''density'' superadditivity holds without ''rate'' superadditivity. Note that the term superadditive development is usually ''not'' used to mean density superadditivity: the image density obtained from the combined agents is greater than the sum of the density from each agent used alone. Mechanism There were several historical theories about the mechanism of superadditive development, until G. I. P. Levenson elucidated the regeneration mechanism. It is useful to r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenidone
Phenidone (1-phenyl-3-pyrazolidinone) is an organic compound that is primarily used as a photographic developer. It has five to ten times the developing power as Metol, capable of achieving the same level of development in both less time and at a lower concentration. It also has low toxicity and unlike some other developers, does not cause dermatitis Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened ... upon skin contact.''Merck Index of Chemicals and Drugs, 9th ed.'' monograph 7115 As a developer, Phenidone is typically used in conjunction with hydroquinone for black and white photography and performs better at lower pH levels. Phenidone is Ilford's trademark for this material, which was first filed on Feb. 24, 1953, but has since expired. Although the compound was first prepared in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P-aminophenol
4-Aminophenol (or ''para''-aminophenol or ''p''-aminophenol) is an organic compound with the formula H2NC6H4OH. Typically available as a white powder, it is commonly used as a developer for black-and-white film, marketed under the name Rodinal. Reflecting its slightly hydrophilic character, the white powder is moderately soluble in alcohols and can be recrystallized from hot water. In the presence of a base, it oxidizes readily. The methylated derivatives ''N''-methylaminophenol and ''N'',''N''-dimethylaminophenol are of commercial value. The compound is one of three isomeric aminophenols, the other two being 2-aminophenol and 3-aminophenol. __TOC__ Preparation From phenol It is produced from phenol by nitration followed by reduction with iron. Alternatively, the partial hydrogenation of nitrobenzene affords phenylhydroxylamine, which rearranges primarily to 4-aminophenol ( Bamberger rearrangement). :C6H5NO2 + 2 H2 → C6H5NHOH + H2O :C6H5NHOH → HOC6H4NH2 From ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AGFA
Agfa-Gevaert N.V. (Agfa) is a Belgian-German multinational corporation that develops, manufactures, and distributes Analog photography, analogue and digital imaging products, software, and systems. The company began as a dye manufacturer in 1867. In 1925, the company merged with several other German chemical companies to become chemicals giant IG Farben. IG Farben would go on to play major role in the economy of Nazi Germany. It extensively employed Forced labour under German rule during World War II, forced labour during the Nazi period, and produced Zyklon B poison gas used in the Holocaust. IG Farben was disestablished by the Allies in 1945. AGFA was reconstituted (as a subsidiary of Bayer) from the remnants of IG Farben in 1952. Agfa photographic film and cameras were once prominent consumer products. In 2004, the consumer imaging division was sold to a company founded via management buyout. AgfaPhoto, AgfaPhoto GmbH, as the new company was called, filed for bankruptcy after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
