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Herz Reaction
The Herz reaction, named after the chemist Richard Herz, is the chemical conversion of an aniline-derivative (1) to a so-called Herz salt (2) with disulfur dichloride, followed by hydrolysis of this Herz salt (2) to the corresponding sodium thiolate (3): Applications Benzothiadiazoles The Herz salts hydrolyze to give aminothiophenols, which are suitable for diazotization, giving Benzothiadiazoles. Benzothiazoles The sodium thiolate can be converted to an intermediate zinc mercaptide with zinc sulfate, followed by reaction of the mercaptide with for instance benzoyl chloride, forming a 1,3-benzothiazole. Dyes Aniline 5 is converted to compound 6, in three steps; # conversion to an ortho- aminothiol through the Herz-reaction (aniline 5 and disulfur dichloride), followed by # conversion to an ortho-aminoarylthioglycolacid and # conversion of the aromatic amine function to a nitrile via the Sandmeyer reaction. # In a last step the nitrile is hydrolysed resulting in 6. This com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Herz
Richard Herz (July 21, 1867 – November 18, 1936) was a German chemist. He discovered the Herz reaction. He studied chemistry at the University of Heidelberg, at the Technical College of Berlin and at the University of Berlin Humboldt-Universität zu Berlin (german: Humboldt-Universität zu Berlin, abbreviated HU Berlin) is a German public research university in the central borough of Mitte in Berlin. It was established by Frederick William III on the initiative ..., and earned his PhD in 1891. From 1892 he was employed by the Leonhardt und Co. Works in Mühlheim am Main and in 1895 he joined a British firm, Levinstein, in Manchester. He was recruited by Cassella in 1899, and played a key role in the company's development of sulfur dyes. He received power of procuration in 1918 and became deputy director in 1925. He retired in 1931.Winfried R. Pötsch, Annelore Fischer, Wolfgang Müller: ''Lexikon bedeutender Chemiker'', Harri Deutsch 1989, , p. 200. References 18 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrile
In organic chemistry, a nitrile is any organic compound that has a functional group. The prefix '' cyano-'' is used interchangeably with the term ''nitrile'' in industrial literature. Nitriles are found in many useful compounds, including methyl cyanoacrylate, used in super glue, and nitrile rubber, a nitrile-containing polymer used in latex-free laboratory and medical gloves. Nitrile rubber is also widely used as automotive and other seals since it is resistant to fuels and oils. Organic compounds containing multiple nitrile groups are known as cyanocarbons. Inorganic compounds containing the group are not called nitriles, but cyanides instead. Though both nitriles and cyanides can be derived from cyanide salts, most nitriles are not nearly as toxic. Structure and basic properties The N−C−C geometry is linear in nitriles, reflecting the sp hybridization of the triply bonded carbon. The C−N distance is short at 1.16 Å, consistent with a triple bond. Nitr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Addition Reactions
Addition (usually signified by the plus symbol ) is one of the four basic operations of arithmetic, the other three being subtraction, multiplication and division. The addition of two whole numbers results in the total amount or '' sum'' of those values combined. The example in the adjacent image shows a combination of three apples and two apples, making a total of five apples. This observation is equivalent to the mathematical expression (that is, "3 ''plus'' 2 is equal to 5"). Besides counting items, addition can also be defined and executed without referring to concrete objects, using abstractions called numbers instead, such as integers, real numbers and complex numbers. Addition belongs to arithmetic, a branch of mathematics. In algebra, another area of mathematics, addition can also be performed on abstract objects such as vectors, matrices, subspaces and subgroups. Addition has several important properties. It is commutative, meaning that the order of the operan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herz02
{{disambiguation, given name ...
Herz is the German word for ''heart''. It may refer to: * Herz (surname) * Herz Bergner (1907–1970), Polish-born Australian novelist * Herz Cerfbeer of Medelsheim (1730–1793), French Jewish philanthropist * Herz., author abbreviation of German botanist T. K. G. Herzog (1880–1961) * ''Herz'' (album), an album by Rosenstolz * Salle des Concerts Herz, a former concert hall in Paris * Herz Glacier, South Georgia Island, Antarctica * Herz (lesbian bar), a lesbian bar in Mobile, Alabama See also * Herz-9, an Iranian air defense system * Hertz (other) The hertz (symbol: Hz) is the SI derived unit of frequency. Hertz may also refer to: People * Hertz (name), a German surname that has also been used as a given name. ** Heinrich Hertz, (1857–1894), German physicist after whom the unit of frequ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indigo Dye
Indigo dye is an organic compound with a distinctive blue color. Historically, indigo was a natural dye extracted from the leaves of some plants of the ''Indigofera'' genus, in particular '' Indigofera tinctoria''; dye-bearing ''Indigofera'' plants were commonly grown and used throughout the world, in Asia in particular, as an important crop, with the production of indigo dyestuff economically important due to the previous rarity of some blue dyestuffs historically. Most indigo dye produced today is synthetic, constituting several thousand tons each year. It is most commonly associated with the production of denim cloth and blue jeans, where its properties allow for effects such as stone washing and acid washing to be applied quickly. Uses The primary use for indigo is as a dye for cotton yarn, mainly used in the production of denim cloth suitable for blue jeans; on average, a pair of blue jeans requires just to of dye. Smaller quantities are used in the dyeing of wool a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isatin
Isatin, also known as tribulin, is an organic compound derived from indole with formula C8H5NO2. The compound was first obtained by Otto Linné Erdman and Auguste Laurent in 1840 as a product from the oxidation of indigo dye by nitric acid and chromic acid, chromic acids. Isatin is a well-known natural product which can be found in plants of the genus ''Isatis'', in ''Couroupita guianensis'', and also in humans, as a metabolic derivative of adrenaline. It looks like a red-orange powder, and it is usually employed as building block for the synthesis of a wide variety of biological activity, biologically active compounds including antitumor antibiotic, antitumorals, antiviral drug, antivirals, anti-HIVs, and antitubercular agent, antituberculars. The isatin core is also responsible for the color of “Maya blue” and “Maya yellow” dyes. Synthesis Sandmeyer methodology The Sandmeyer methodology is the oldest and straightforward way for the synthesis of isatin. The m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acenaphthoquinone
Acenaphthoquinone is a quinone derived from acenaphthene. It is a water-insoluble yellow solid. It is a precursor to some agrichemicals and dyes. Preparation The compound is prepared in the laboratory by oxidation of acenaphthene with potassium dichromate Potassium dichromate, , is a common inorganic chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications. As with all hexavalent chromium compounds, it is acutely and chronically harmful to health .... Commercially, oxidation is effected with peroxide. Over-oxidation gives naphthalenedicarboxylic anhydride. References External links National Pollutant Inventory - Polycyclic Aromatic Hydrocarbon Fact Sheet Quinones Polycyclic aromatic compounds Enones {{aromatic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condensation
Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor to liquid water when in contact with a liquid or solid surface or cloud condensation nuclei within the atmosphere. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition. Initiation Condensation is initiated by the formation of atomic/molecular clusters of that species within its gaseous volume—like rain drop or snow flake formation within clouds—or at the contact between such gaseous phase and a liquid or solid surface. In clouds, this can be catalyzed by water-nucleating proteins, produced by atmospheric microbes, which are capable of binding gaseous or liquid water molecules. Reversibility scenarios A few distinct reversibility scenarios emerge here with respect to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one of the most important branches of organic chemistry. There are several main areas of research within the general area of organic synthesis: '' total synthesis'', ''semisynthesis'', and ''methodology''. Total synthesis A total synthesis is the complete chemical synthesis of complex organic molecules from simple, commercially available petrochemical or natural precursors. Total synthesis may be accomplished either via a linear or convergent approach. In a ''linear'' synthesis—often adequate for simple structures—several steps are performed one after another until the molecule is complete; the chemical compounds made in each step are called synthetic intermediates. Most often, each step in a synthesis refers to a separate rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decarboxylation
Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO2). Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is the first chemical step in photosynthesis, is called carboxylation, the addition of CO2 to a compound. Enzymes that catalyze decarboxylations are called decarboxylases or, the more formal term, carboxy-lyases ( EC number 4.1.1). In organic chemistry The term "decarboxylation" usually means replacement of a carboxyl group () with a hydrogen atom: :RCO2H -> RH + CO2 Decarboxylation is one of the oldest known organic reactions. It is one of the processes assumed to accompany pyrolysis and destructive distillation. Metal salts, especially copper compounds, facilitate the reaction via the intermediacy of metal carboxylate complexes. Decarboxylation of aryl carboxylates can generate the equivalent of the corresponding aryl anion, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandmeyer Reaction
The Sandmeyer reaction is a chemical reaction used to synthesize aryl halides from aryl diazonium salts using copper salts as reagents or catalysts. It is an example of a radical-nucleophilic aromatic substitution. The Sandmeyer reaction provides a method through which one can perform unique transformations on benzene, such as halogenation, cyanation, trifluoromethylation, and hydroxylation. : The reaction was discovered in 1884 by Swiss chemist Traugott Sandmeyer, when he attempted to synthesize phenylacetylene from benzenediazonium chloride and copper(I) acetylide. Instead, the main product he isolated was chlorobenzene. In modern times, the Sandmeyer reaction refers to any method for substitution of an aromatic amino group via preparation of its diazonium salt followed by its displacement with a nucleophile in the presence of catalytic copper(I) salts. (Due to the low cost of copper salts, a stoichiometric amount is often employed for better reactivity even when catalysis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
