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Elbs Persulfate Oxidation
The Elbs persulfate oxidation is the organic reaction of phenols with alkaline potassium persulfate to form ''para''-diphenols. The reaction is generally performed in water at room temperatures or below, using equimolar quantities of reagents. Several reviews have been published. Scope and mechanism The reaction is disadvantaged by moderate to low chemical yields with recovery of starting material and complete consumption of the persulfate. It is suggested that the phenol in many cases is a catalyst converting the persulfate into a sulfate. Despite this, the Elbs reaction remains generally useful in a research setting, as it is simple to perform and is tolerant of a wide range of other functional groups, which are not oxidised under these conditions. A reaction mechanism has been postulated which accounts for the observed ''para'' substitution featuring the tautomeric ''para'' carbanion of the starting phenolate ion:{{cite journal , author = Behrman, E. J. , title = The Elbs a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karl Elbs
Karl Elbs (13 September 1858 in Alt-Breisach, Baden, Germany – 24 August 1933) was a German chemist. He is credited with developing the Elbs reaction for the synthesis of anthracene. He is also responsible for the Elbs persulfate oxidation. From 1877 he studied natural sciences at the University of Freiburg, receiving his doctorate in 1880 under the direction of Adolf Karl Ludwig Claus. In 1887 he obtained his habilitation, then in 1894 was named a full professor at the University of Giessen, where he served as director of the physico-chemistry laboratory. Published works * ''Die synthetischen Darstellungsmethoden der Kohlenstoff-Verbindungen'', 1889 – Synthetic methods of preparation of carbon compounds Carbon compounds are defined as chemical substances containing carbon. More compounds of carbon exist than any other chemical element except for hydrogen. Organic carbon compounds are far more numerous than inorganic carbon compounds. In general .... * ''Die Akkumul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tautomer
Tautomers () are structural isomers (constitutional isomers) of chemical compounds that readily interconvert. The chemical reaction interconverting the two is called tautomerization. This conversion commonly results from the relocation of a hydrogen atom within the compound. The phenomenon of tautomerization is called tautomerism, also called desmotropism. Tautomerism is for example relevant to the behavior of amino acids and nucleic acids, two of the fundamental building blocks of life. Care should be taken not to confuse tautomers with depictions of "contributing structures" in chemical resonance. Tautomers are distinct chemical species that can be distinguished by their differing atomic connectivities, molecular geometries, and physicochemical and spectroscopic properties, whereas resonance forms are merely alternative Lewis structure (valence bond theory) depictions of a single chemical species, whose true structure is best described as the "average" of the idealized, hypothe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dakin Reaction
The Dakin oxidation (or Dakin reaction) is an organic redox reaction in which an '' ortho''- or ''para''-hydroxylated phenyl aldehyde (2-hydroxybenzaldehyde or 4-hydroxybenzaldehyde) or ketone reacts with hydrogen peroxide in base to form a benzenediol and a carboxylate. Overall, the carbonyl group is oxidized, and the hydrogen peroxide is reduced. The Dakin oxidation, which is closely related to the Baeyer–Villiger oxidation, is not to be confused with the Dakin–West reaction, though both are named after Henry Drysdale Dakin. Reaction mechanism The Dakin oxidation starts with nucleophilic addition of a hydroperoxide anion to the carbonyl carbon, forming a tetrahedral intermediate (2). The intermediate collapses, causing ,2aryl migration, hydroxide elimination, and formation of a phenyl ester (3). The phenyl ester is subsequently hydrolyzed: nucleophilic addition of hydroxide from solution to the ester carbonyl carbon forms a second tetrahedral intermediate (4), which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boyland–Sims Oxidation
The Boyland–Sims oxidation is the chemical reaction of anilines with alkaline potassium persulfate, which after hydrolysis forms ''ortho''-hydroxyl anilines. The reaction is generally performed in water at room temperatures or below, using equimolar quantities of reagents. The ''ortho''-isomer is formed predominantly. However, the ''para''-sulfate is formed in small amounts with certain anilines. Scope and mechanism The reaction is disadvantaged by moderate to low chemical yields, but is simple to perform and uses mild conditions. Some competitive oxidation of the nitrogen has been observed. Behrman has shown that the first intermediate in the Boyland–Sims oxidation is the formation of an arylhydroxylamine-O-sulfate (2). Rearrangement of this zwitterionic intermediate forms the ortho- sulfate (5), which then hydrolyses to form the ortho-hydroxyl aniline. See also * Elbs persulfate oxidation The Elbs persulfate oxidation is the organic reaction of phenols with alkaline po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxyl Group
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy groups. Both the negatively charged anion , called hydroxide, and the neutral radical , known as the hydroxyl radical, consist of an unbonded hydroxy group. According to IUPAC definitions, the term ''hydroxyl'' refers to the hydroxyl radical () only, while the functional group is called a ''hydroxy group''. Properties Water, alcohols, carboxylic acids, and many other hydroxy-containing compounds can be readily deprotonated due to a large difference between the electronegativity of oxygen (3.5) and that of hydrogen (2.1). Hydroxy-containing compounds engage in intermolecular hydrogen bonding increasing the electrostatic attraction between molecules and thus to higher boiling and melting points than found for compounds that lack this func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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 tetrahedral molecular geometry of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peroxodisulfate
The peroxydisulfate ion, , is an oxyanion, the anion of peroxydisulfuric acid. It is commonly referred to as persulfate, but this term also refers to the peroxomonosulfate ion, . It is also called ''peroxodisulfate''. Approximately 500,000 tons of salts containing this anion are produced annually. Important salts include sodium persulfate (Na2S2O8), potassium persulfate (K2S2O8), and ammonium persulfate ((NH4)2S2O8). These salts are colourless, water-soluble solids that are strong oxidants.: Applications Salts of peroxydisulfate are mainly used to initiate the polymerization of various alkenes, including styrene, acrylonitrile, and fluoroalkenes. Polymerization is initiated by the homolysis of the peroxydisulfate: : 3SO–OSO3sup>2− 2 O4sup>•− Moreover, sodium peroxydisulfate can be used for soil and groundwater remediation, water and wastewater treatment, and etching of copper on circuit boards. It has also been used to produce hair lighteners and bleaches, medical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleophilic Displacement
In chemistry, a nucleophilic substitution is a class of chemical reactions in which an electron-rich chemical species (known as a nucleophile) replaces a functional group within another electron-deficient molecule (known as the electrophile). The molecule that contains the electrophile and the leaving functional group is called the substrate. The most general form of the reaction may be given as the following: :\text\mathbf + \ce + \text\mathbf The electron pair (:) from the nucleophile (Nuc) attacks the substrate () and bonds with it. Simultaneously, the leaving group (LG) departs with an electron pair. The principal product in this case is . The nucleophile may be electrically neutral or negatively charged, whereas the substrate is typically neutral or positively charged. An example of nucleophilic substitution is the hydrolysis of an alkyl bromide, R-Br under basic conditions, where the attacking nucleophile is hydroxyl () and the leaving group is bromide (). :R-Br + OH- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beilstein Journal Of Organic Chemistry
The ''Beilstein Journal of Organic Chemistry'' is a peer-reviewed open-access scientific journal established in 2005. It is published by the Beilstein Institute for the Advancement of Chemical Sciences, a German non-profit foundation. The editor-in-chief is Peter Seeberger (Max Planck Institute of Colloids and Interfaces). According to the ''Journal Citation Reports'', the journal has a 2020 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 2.88. Scientific videos are available for selected articles of the journal. References External links * Organic chemistry journals Open access journals Creative Commons Attribution-licensed journals Publications established in 2005 English-language journals BioMed Central academic journals {{chem-journal-stu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbanion
In organic chemistry, a carbanion is an anion in which carbon is trivalent (forms three bonds) and bears a formal negative charge (in at least one significant resonance form). Formally, a carbanion is the conjugate base of a carbon acid: :R3CH\, + \ddot^- -> \mathbf + HB where B stands for the base. The carbanions formed from deprotonation of alkanes (at an sp3 carbon), alkenes (at an sp2 carbon), arenes (at an sp2 carbon), and alkynes (at an sp carbon) are known as alkyl, alkenyl (vinyl), aryl, and alkynyl (acetylide) anions, respectively. Carbanions have a concentration of electron density at the negatively charged carbon, which, in most cases, reacts efficiently with a variety of electrophiles of varying strengths, including carbonyl groups, imines/ iminium salts, halogenating reagents (e.g., ''N''-bromosuccinimide and diiodine), and proton donors. A carbanion is one of several reactive intermediates in organic chemistry. In organic synthesis, organolithium reagents a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Mechanism
In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical change occurs. A chemical mechanism is a theoretical conjecture that tries to describe in detail what takes place at each stage of an overall chemical reaction. The detailed steps of a reaction are not observable in most cases. The conjectured mechanism is chosen because it is thermodynamically feasible, and has experimental support in isolated intermediates (see next section) or other quantitative and qualitative characteristics of the reaction. It also describes each reactive intermediate, activated complex, and transition state, and which bonds are broken (and in what order), and which bonds are formed (and in what order). A complete mechanism must also explain the reason for the reactants and catalyst used, the stereochemistry observed in reactants and products, all products formed and the amount of each. The electron or arrow pushing method is often used in i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
