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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] |
Beta-naphthol Tautomerism
2-Naphthol, or β-naphthol, is a fluorescence, fluorescent colorless (or occasionally yellow) crystalline solid with the formula C10H7OH. It is an isomer of 1-Naphthol, 1-naphthol, differing by the location of the hydroxide, hydroxyl group on the naphthalene ring. The naphthols are naphthalene homologues of phenol, but more reactive. Both isomers are soluble in simple Alcohol (chemistry), 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-deri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sudan I
Sudan I (also known as CI Solvent Yellow 14 or Solvent Orange R) 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 for use in food in many countries (including the United States and the European Union) due to its classification as a category 3 carcinogen by the International Agency for Research on Cancer (not classifiable as to its carcinogenicity in humans). Nevertheless, Sudan I remains valuable as a coloring reagent for non-food-related uses, such as in the formulation of orange-colored smoke. Application The Sudan dyes are a group of azo compounds which have been used to color hydrocarbon solvents, oils, fats, waxes, shoes, and floor polishes. As recently as 1974, about of Sudan I, of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-aminonaphthalene
2-Naphthylamine or 2-aminonaphthalene is one of two isomeric aminonaphthalenes, compounds with the formula C10H7NH2. It is a colorless solid, but samples take on a reddish color in air because of oxidation. It was formerly used to make azo dyes, but it is a known carcinogen and has largely been replaced by less toxic compounds.Gerald Booth "Naphthalene Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. . Preparation 2-Naphthylamine is prepared by heating 2-naphthol with ammonium zinc chloride to 200-210 °C, the Bucherer reaction. Its acetyl derivative can be obtained by heating 2-naphthol with ammonium acetate to 270-280 °C. Reactions It gives no color with iron(III) chloride. When reduced by sodium in boiling amyl alcohol solution, it forms tetrahydro-3-naphthylamine, which exhibits the properties of the aliphatic amines in that it is strongly alkaline in reaction, has an ammoniacal odor and cannot be diazotized. On oxidation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1-Naphthol
1-Naphthol, or α-naphthol, is an organic compound with the formula . It is a fluorescent white solid. 1-Naphthol differs from its isomer 2-naphthol by the location of the hydroxyl group on the naphthalene ring. The naphthols are naphthalene homologues of phenol. Both isomers are soluble in simple organic solvents. They are precursors to a variety of useful compounds. Production 1-Naphthol is prepared by two main routes. In one method, naphthalene is nitrated to give 1-nitronaphthalene, which is hydrogenated to the amine followed by hydrolysis: : : : Alternatively, naphthalene is hydrogenated to tetralin, which is oxidized to 1-tetralone, which undergoes dehydrogenation. Reactions Some reactions of 1-naphthol are explicable with reference to its tautomerism, which produces a small amount of the keto tautomer. : One consequence of this tautomerism is the Bucherer reaction, the ammonolysis of 1-naphthol to give 1-aminonaphthalene. 1-Naphthol biodegrades via format ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naphthalene
Naphthalene is an organic compound with formula . It is the simplest polycyclic aromatic hydrocarbon, and is a white Crystal, crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 Parts-per notation, ppm by mass. As an Aromaticity, aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings. It is the main ingredient of traditional mothballs. History In the early 1820s, two separate reports described a white solid with a pungent odor derived from the distillation of coal tar. In 1821, John Kidd (chemist), John Kidd cited these two disclosures and then described many of this substance's properties and the means of its production. He proposed the name ''naphthaline'', as it had been derived from a kind of naphtha (a broad term encompassing any volatile, flammable liquid hydrocarbon mixture, including coal tar). Naphthalene's chemical formula was determined by Michael Faraday in 1826. The structure of two f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sudan II
Sudan II (Solvent Orange 7, C.I. 12140, C18H16N2O) is a lysochrome (fat-soluble dye) azo dye used for staining of triglycerides in frozen sections, and some protein bound lipids and lipoproteins on paraffin sections. It has the appearance of red powder with melting point 156–158 °C and maximum absorption at 493(420) nm. Uses In industry, it is used to color nonpolar substances like oils, fats, waxes, greases, various hydrocarbon products, and acrylic emulsion An emulsion is a mixture of two or more liquids that are normally Miscibility, immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloi ...s. It was used as food dye under the designation FD&C Red 32 in the US until the FDA banned its use in food in 1956 due to toxicity. References {{Stains Azo dyes Sudan dyes 2-Naphthols Alkyl-substituted benzenes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-Naphthalenethiol
2-Naphthalenethiol is an organosulfur compound with the formula C10H7SH. It is a white solid. It is one of two monothiols of naphthalene Naphthalene is an organic compound with formula . It is the simplest polycyclic aromatic hydrocarbon, and is a white Crystal, crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 Parts-per notation ..., the other being 1-naphthalenethiol. Synthesis and reactions 2-Naphthalenethiol is prepared from 2-naphthol by the Newman–Kwart rearrangement starting from a thiocarbamate. It undergoes lithiation at the 1 and 3-position. It can be used as a flavouring agent and has been described as having an “artichoke”, “meaty” and “creamy” taste”. References {{DEFAULTSORT:Naphthalenethiol, 2- Thiols 2-Naphthyl compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sudan Dye
Sudan stains and Sudan dyes are synthetic organic compounds that are used as dyes for various plastics (plastic colorants) and are also used to stain sudanophilic biological samples, usually lipids. Sudan II, Sudan III, Sudan IV, Oil Red O, and Sudan Black B are important members of this class of compounds (see images below). Staining Sudan dyes have high affinity to fats, therefore they are used to demonstrate triglycerides, lipids, and lipoproteins. Alcoholic solutions of Sudan dyes are usually used, however pyridine solutions can be used in some situations as well. Sudan stain test is often used to determine the level of fecal fat to diagnose steatorrhea. A small sample is dissolved in water or saline, glacial acetic acid is added to hydrolyze the insoluble salts of fatty acids, a few drops of alcoholic solution of Sudan III are added, the sample is spread on a microscopic slide, and heated twice to boil. Normally a stool sample should show only a few drops of red-orange stained ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diazonium Salt
Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group 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. The parent, compound where R is hydrogen, is diazenylium. Structure and general properties Arene derivatives According to X-ray crystallography the linkage is linear in typical diazonium salts. The bond distance in benzenediazonium tetrafluoroborate is 1.083(3) Å, which is almost identical to that for dinitrogen molecule (N≡N). The linear free energy constants σm and σp indicate that the diazonium group is strongly electron-withdrawing. Thus, the diazonio-substituted phenols and benzoic acids have greatly reduced p''K''a values compared to their unsubstituted counterparts. The p''K''a of phenolic proton of 4-hydroxybenzenediazonium is 3.4, versus 9.9 for phenol itself. In other words, the diazonium group raises the ionization constant ''K'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CuCl2 Naphthol Coupling
Copper(I) chloride, commonly called cuprous chloride, is the lower chloride of copper, with the formula CuCl. The substance is a white solid sparingly soluble in water, but very soluble in concentrated hydrochloric acid. Impure samples appear green due to the presence of copper(II) chloride (CuCl2). History Copper(I) chloride was first prepared by Robert Boyle and designated rosin of copper in the mid-seventeenth century from mercury(II) chloride ("Venetian sublimate") and copper metal: :HgCl2 + 2 Cu → 2 CuCl + Hg In 1799, Joseph Proust first differentiated two different chlorides of copper. He prepared CuCl (which he called white muriate of copper) by heating CuCl2 at red heat in the absence of air, causing it to lose half of its combined chlorine followed by removing residual CuCl2 by washing with water. An acidic solution of CuCl was formerly used to analyze carbon monoxide content in gases, for example in Hempel's gas apparatus where the CuCl absorbs the carbon mono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymmetric Catalysis
Enantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of Chirality (chemistry), chirality are formed in a substrate molecule and which produces the stereoisomeric (enantiomeric or diastereomeric) products in Enantiomeric excess, unequal amounts." Put more simply: it is the synthesis of a compound by a method that favors the formation of a specific enantiomer or diastereomer. Enantiomers are stereoisomers that have opposite configurations at every chiral center. Diastereomers are stereoisomers that differ at one or more chiral centers. Enantioselective synthesis is a key process in modern chemistry and is particularly important in the field of pharmaceuticals, as the different enantiomers or diastereomers of a molecule often have different biological activity. Overview Many of the building blocks of biological systems such as sugars a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C2-Symmetric Ligands
In homogeneous catalysis, ''C''2-symmetric ligands refer to ligands that lack mirror symmetry but have ''C''2 symmetry (two-fold rotational symmetry). Such ligands are usually bidentate and are valuable in catalysis. The ''C''2 symmetry of ligands limits the number of possible reaction pathways and thereby increases enantioselectivity, relative to asymmetrical analogues. ''C''2-symmetric ligands are a subset of chiral ligands. Chiral ligands, including ''C''2-symmetric ligands, combine with metals or other groups to form chiral catalysts. These catalysts engage in enantioselective chemical synthesis, in which chirality in the catalyst yields chirality in the reaction product. Examples An early ''C''2-symmetric ligand, diphosphine catalytic ligand DIPAMP, was developed in 1968 by William S. Knowles and coworkers of Monsanto Company, who shared the 2001 Nobel Prize in Chemistry. This ligand was used in the industrial production of -DOPA. : Some classes of ''C''2-symmetric li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
