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1-Nitroso-2-naphthol
1-Nitroso-2-naphthol is an organic compound with the formula . It is one of several possible nitrosonaphthols, and the most studied for applications as an indicator and a dye. Synthesis and reactions 1-Nitroso-2-naphthol can be prepared by treatment of 2-naphthol with nitrous acid: : Its conjugate base A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid gives a proton () to a base—in other words, it is a base with a hydrogen ion added to it, as it loses a hydrogen ion in the reve ... forms deeply colored complexes with iron(II) and cobalt(II), complexes (C10H6(NO)O)3sup>2-. The deep colors of these complexes results from the delocalized bonding within each five-membered chelate ring. These species can be classified as nitroso complexes. See also * Naphthol Green B, the iron complex of a sulfonated derivative of 1-nitroso-2-naphthol References {{DEFAULTSORT:Nitroso-2-naphthol, 1- 2-Naphthols Nitroso compou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-Naphthol
2-Naphthol, or β-naphthol, is a fluorescent colorless (or occasionally yellow) crystalline solid with the formula C10H7OH. It is an isomer of 1-naphthol, differing by the location of the hydroxyl group on the naphthalene ring. The naphthols are naphthalene homologues of phenol, but more reactive. Both isomers are soluble in simple alcohols, ethers, and chloroform. 2-Naphthol is a widely used intermediate for the production of dyes and other compounds. Production Traditionally, 2-naphthol is produced by a two-step process that begins with the sulfonation of naphthalene in sulfuric acid:full-text PDF/ref> :C10H8 + H2SO4 → C10H7SO3H + H2O The sulfonic acid group is then cleaved in molten sodium hydroxide: :C10H7(SO3H) + 3 NaOH → C10H7ONa + Na2SO3 + 2 H2O Neutralization of the product with acid gives 2-naphthol. 2-Naphthol can also be produced by a method analogous to the cumene process. 2-Naphthol-derived dyes The Sudan dyes are popular dyes noted for being ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition Metal Nitroso Complexes
Structure of the dye Naphthol Green B, which features of nitroso ligand bound to Fe(III). Transition metal nitroso complexes are coordination complexes containing one or more organonitroso ligands (RNO). Structure and bonding Organic nitroso compounds bind to metals in several ways, but most commonly as monodentate N-bonded ligands. Also known are O-bonded, η2-N,O-bonded. Dimers of organic nitroso compounds also bind in a κ2--O,O bidentate manner. Illustrative are , where a pair nitrosobenzenes are monodentate, and where two nitrosobenzenes bridge. Chelating nitroso ligands : Arylnitroso compounds with a flanking hydroxy group are a well-developed, e.g. 1-nitroso-2-naphthol. They are precursors to anionic N,O chelating ligands. Chelating dinitrosoarenes are uncommon but have been investigated. Synthesis Organic nitroso complexes can be prepared from preformed organic nitroso precursors. These precursors usually exist as N-N bonded dimers, but the dimer dissociates read ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naphthol Green B
Naphthol Green B is a coordination complex of iron that is used as a dye. The ligand is a sulfonated derivative of 1-nitroso-2-naphthol. Structure Naphthol Green B is the sodium salt of Naphthol Green Y (C.I. 10005). The organic ligands each bind to iron as bidentate ligands through the nitrogen and the anionic phenoxide groups. Three ligands are bound to the iron. Applications Its absorption maximum is 714 nm in water.Horobin, RW. und Kiernan, JA. (2002): ''Conn's Biological Stains: A Handbook of Dyes, Stains and Fluorochromes for Use in Biology and Medicine''. BIOS Scientific Publ., 10th edition; ; page 101 and 102 It is water-soluble. Naphthol Green B is used in histology to stain collagen.''Histological and Histochemical Methods: Theory and Practice'', 4th edition, J. A. Kiernan Moreover, it is used for polychrome stains with animal tissue. For industry purposes Naphthol Green B is used for staining wool, nylon, paper, anoxidized aluminium and soap Soap is a sal ... [...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] |
Complexometric Indicator
A complexometric indicator is an ionochromic dye that undergoes a definite color change in presence of specific metal ions. It forms a weak complex with the ions present in the solution, which has a significantly different color from the form existing outside the complex. Complexometric indicators are also known as pM indicators. Complexometric titration In analytical chemistry, complexometric indicators are used in complexometric titration to indicate the exact moment when all the metal ions in the solution are sequestered by a chelating agent (most usually EDTA). Such indicators are also called metallochromic indicators. The indicator may be present in another liquid phase in equilibrium with the titrated phase, the indicator is described as extraction indicator. Some complexometric indicators are sensitive to air and are destroyed. When such solution loses color during titration, a drop or two of fresh indicator may have to be added. Examples Complexometric indicators are wat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrous Acid
Nitrous acid (molecular formula ) is a weak and monoprotic acid known only in solution, in the gas phase, and in the form of nitrite () salts. It was discovered by Carl Wilhelm Scheele, who called it " phlogisticated acid of niter". Nitrous acid is used to make diazonium salts from amines. The resulting diazonium salts are reagents in azo coupling reactions to give azo dyes. Structure In the gas phase, the planar nitrous acid molecule can adopt both a ''syn'' and an ''anti'' form. The ''anti'' form predominates at room temperature, and IR measurements indicate it is more stable by around 2.3 kJ/mol. p. 462. Image:Trans-nitrous-acid-2D-dimensions.png , Dimensions of the ''anti'' form(from the microwave spectrum) Image:Trans-nitrous-acid-3D-balls.png , Model of the ''anti'' form Image:Cis-nitrous-acid-3D-balls.png , ''syn'' form Preparation and decomposition Free, gaseous nitrous acid is unstable, rapidly disproportionating to nitric oxides: :2 HNO2 → NO2 + ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conjugate Base
A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid gives a proton () to a base—in other words, it is a base with a hydrogen ion added to it, as it loses a hydrogen ion in the reverse reaction. On the other hand, a conjugate base is what remains after an acid has donated a proton during a chemical reaction. Hence, a conjugate base is a substance formed by the removal of a proton from an acid, as it can gain a hydrogen ion in the reverse reaction. Because some acids can give multiple protons, the conjugate base of an acid may itself be acidic. In summary, this can be represented as the following chemical reaction: \text + \text \; \ce \; \text + \text Johannes Nicolaus Brønsted and Martin Lowry introduced the Brønsted–Lowry theory, which said that any compound that can give a proton to another compound is an acid, and the compound that receives the proton is a base. A proton is a subatomic particle in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
