|
Dimethyldioxirane
Dimethyldioxirane (DMDO), also referred to as Murray's reagent in reference to Robert W. Murray, is a dioxirane derived from acetone and can be considered as a monomer of acetone peroxide. It is a powerful yet selective oxidizing agent which finds use in organic synthesis. It is known only in the form of a dilute solution, usually in acetone, and hence the properties of the pure material are largely unknown. Synthesis DMDO is not commercially available because of its instability. DMDO can be prepared as dilute solutions (~0.1 M) by treatment of acetone with potassium peroxymonosulfate , usually in the form of Oxone (2KHSO5·KHSO4·K2SO4). : The preparation of DMDO is rather inefficient (typical yields < 3%) and typically only yields a relatively dilute solution in acetone (only up to approximately 0.1 M). This is tolerable as preparation uses inexpensive substances: |
Dioxirane
In chemistry, dioxirane is a compound with formula , whose molecule consists of a ring with one carbon and two oxygen atoms, and two hydrogen atoms attached to the carbon. It is a heterocyclic compound, the smallest cyclic organic peroxide. The compound itself is highly unstable and has never been observed at room temperature. Derivatives in which the hydrogens are replaced by other functional groups are called dioxiranes, and may be more stable. Some of them, such as dimethyldioxirane (DMDO) and the more reactive methyl(trifluoromethyl)dioxirane, are used in organic synthesis as oxidizing reagents, most notably as the key catalytic intermediate in the Shi epoxidation reaction. Difluorodioxirane, which boils at about –80 to –90 °C, is one of the very few dioxirane derivatives that is stable in pure form at room temperature. Synthesis Dioxirane is highly unstable and the majority of studies of it have been computational chemistry, computational; it has been detected ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Peroxymonosulfate
Potassium peroxymonosulfate is widely used as an oxidizing agent. It is the potassium salt of peroxymonosulfuric acid. Usually potassium peroxymonosulfate refers to the triple salt known as oxone. The standard electrode potential for potassium peroxymonosulfate is +1.81 V with a half reaction generating the hydrogen sulfate (): ::HSO5− + 2 H+ + 2 e− → HSO4− + H2O Oxone Potassium peroxymonosulfate per se is a relatively obscure salt, but its derivative called oxone is of commercial value. Oxone refers to the triple salt 2KHSO5·KHSO4·K2SO4. Oxone has a longer shelflife than does potassium peroxymonosulfate. A white, water-soluble solid, oxone loses <1% of its oxidizing power per month. Production Oxone is produced from peroxysulfuric acid, which is generated in situ by combining oleum and |
Oxone
Potassium peroxymonosulfate is widely used as an oxidizing agent. It is the potassium salt of peroxymonosulfuric acid. Usually potassium peroxymonosulfate refers to the triple salt known as oxone. The standard electrode potential for potassium peroxymonosulfate is +1.81 V with a half reaction generating the hydrogen sulfate (): ::HSO5− + 2 H+ + 2 e− → HSO4− + H2O Oxone Potassium peroxymonosulfate per se is a relatively obscure salt, but its derivative called oxone is of commercial value. Oxone refers to the triple salt 2KHSO5·KHSO4·K2SO4. Oxone has a longer shelflife than does potassium peroxymonosulfate. A white, water-soluble solid, oxone loses <1% of its oxidizing power per month. Production Oxone is produced from peroxysulfuric acid, which is generated in situ by combining and |
Dimethyldioxirane Synthesis V
Dimethyldioxirane (DMDO), also referred to as Murray's reagent in reference to Robert W. Murray, is a dioxirane derived from acetone and can be considered as a monomer of acetone peroxide. It is a powerful yet selective oxidizing agent which finds use in organic synthesis. It is known only in the form of a dilute solution, usually in acetone, and hence the properties of the pure material are largely unknown. Synthesis DMDO is not commercially available because of its instability. DMDO can be prepared as dilute solutions (~0.1 M) by treatment of acetone with potassium peroxymonosulfate , usually in the form of Oxone (2KHSO5·KHSO4·K2SO4). : The preparation of DMDO is rather inefficient (typical yields < 3%) and typically only yields a relatively dilute solution in acetone (only up to approximately 0.1 M). This is tolerable as preparation uses inexpensive substances: |
Dioxirane Oxidations
In chemistry, dioxirane is a compound with formula , whose molecule consists of a ring with one carbon and two oxygen atoms, and two hydrogen atoms attached to the carbon. It is a heterocyclic compound, the smallest cyclic organic peroxide. The compound itself is highly unstable and has never been observed at room temperature. Derivatives in which the hydrogens are replaced by other functional groups are called dioxiranes, and may be more stable. Some of them, such as dimethyldioxirane (DMDO) and the more reactive methyl(trifluoromethyl)dioxirane, are used in organic synthesis as oxidizing reagents, most notably as the key catalytic intermediate in the Shi epoxidation reaction. Difluorodioxirane, which boils at about –80 to –90 °C, is one of the very few dioxirane derivatives that is stable in pure form at room temperature. Synthesis Dioxirane is highly unstable and the majority of studies of it have been computational; it has been detected during the low tempera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfide
Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds large families of inorganic and organic compounds, e.g. lead sulfide and dimethyl sulfide. Hydrogen sulfide (H2S) and bisulfide (SH−) are the conjugate acids of sulfide. Chemical properties The sulfide ion, S2−, does not exist in aqueous alkaline solutions of Na2S. Instead sulfide converts to hydrosulfide: :S2− + H2O → SH− + OH− Upon treatment with an acid, sulfide salts convert to hydrogen sulfide: :S2− + H+ → SH− :SH− + H+ → H2S Oxidation of sulfide is a complicated process. Depending on the conditions, the oxidation can produce elemental sulfur, polysulfides, polythionates, sulfite, or sulfate. Metal sulfides react with halogens, forming sulfur and metal salts. :8 MgS + 8 I2 → S8 + 8 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Peroxides
In organic chemistry, organic peroxides are organic compounds containing the peroxide functional group (). If the R′ is hydrogen, the compounds are called hydroperoxides, which are discussed in that article. The O−O bond of peroxides easily breaks, producing free radicals of the form (the dot represents an unpaired electron). Thus, organic peroxides are useful as initiators for some types of polymerisation, such as the epoxy resins used in glass-reinforced plastics. MEKP and benzoyl peroxide are commonly used for this purpose. However, the same property also means that organic peroxides can explosively combust. Organic peroxides, like their inorganic counterparts, are often powerful bleaching agents. Types of organic peroxides Tert-Butyl hydroperoxide Structural Formula V2.svg, ''tert''-Butyl hydroperoxide, a hydroperoxide (formula: ROOH) that is used to epoxide alkenes. Dicumyl peroxide.svg, Dicumyl peroxide, a dialkyl peroxide (formula: ROOR) that is used to init ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reagents For Organic Chemistry
In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a substance ''consumed'' in the course of a chemical reaction. ''Solvents'', though involved in the reaction mechanism, are usually not called reactants. Similarly, '' catalysts'' are not consumed by the reaction, so they are not reactants. In biochemistry, especially in connection with enzyme-catalyzed reactions, the reactants are commonly called substrates. Definitions Organic chemistry In organic chemistry, the term "reagent" denotes a chemical ingredient (a compound or mixture, typically of inorganic or small organic molecules) introduced to cause the desired transformation of an organic substance. Examples include the Collins reagent, Fenton's reagent, and Grignard reagents. Analytical chemistry In analytical chemistry, a reage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shi Epoxidation
The Shi epoxidation is a chemical reaction described as the asymmetric epoxidation of alkenes with oxone (potassium peroxymonosulfate) and a fructose-derived catalyst (1). This reaction is thought to proceed via a dioxirane intermediate, generated from the catalyst ketone by oxone (potassium peroxymonosulfate). The addition of the sulfate group by the oxone facilitates the formation of the dioxirane by acting as a good leaving group during ring closure. It is notable for its use of a non-metal catalyst and represents an early example of organocatalysis. The reaction was first discovered by Yian Shi (史一安, pinyin: Shǐ Yī-ān) of Colorado State University in 1996. History Many attempts at the synthesis of an efficient non-metal catalyst were made before one was discovered. The problem with previous catalysts was the rapid decomposition/oxidation of the dioxirane intermediate and lack of electrophilicity of the reactive ketone. Aromatic ketones were proposed, and many su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nef DMDO
Nef or NEF may refer to: Businesses and organizations * National Energy Foundation, a British charity * National Enrichment Facility, an American uranium enrichment plant * New Economics Foundation, a British think-tank * Near East Foundation, an American international social and economic development organization * National Equity Fund, Inc., an American non-profit syndicator of Low Income Housing Tax Credits * New England Firearms, a brand of H&R Firearms People * Abdou Nef (1995–2013), Algerian footballer * Adolfo Nef (born 1946), Chilean football goalkeeper * Alain Nef (born 1982), Swiss footballer * Francisco Nef (1863–1931), Chilean naval officer and member of the government junta ** Hospital Naval Almirante Nef * Hari Nef (born 1992), American actress, model, and writer * Isabelle Nef (1895–1976), Swiss pianist and harpsichordist * John Ulric Nef (chemist) (1862–1915), discoverer of the Nef reaction * John Ulric Nef (economic historian) (1899–1988) * Karl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synlett
''Synlett'' is an international scientific journal for accounts and rapid communications of original contributions of fundamental research in synthetic organic chemistry. The impact factor of this journal is 2.419 (2017). ''Nature'' featured a brief piece by the editor-in-chief of the journal in 2017, Benjamin List Benjamin ( he, ''Bīnyāmīn''; "Son of (the) right") blue letter bible: https://www.blueletterbible.org/lexicon/h3225/kjv/wlc/0-1/ H3225 - yāmîn - Strong's Hebrew Lexicon (kjv) was the last of the two sons of Jacob and Rachel (Jacob's th ..., where he discussed the journal's experience with the non-traditional peer review system. References Chemistry journals Thieme academic journals Publications established in 1989 {{chem-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nef Reaction
In organic chemistry, the Nef reaction is an organic reaction describing the acid hydrolysis of a salt of a primary or secondary nitroalkane () to an aldehyde () or a ketone () and nitrous oxide (). The reaction has been the subject of several literature reviews. The reaction was reported in 1894 by the chemist John Ulric Nef, who treated the sodium salt of nitroethane with sulfuric acid resulting in an 85–89% yield of nitrous oxide and at least 70% yield of acetaldehyde. However, the reaction was pioneered a year earlier in 1893 by Konovalov, who converted the potassium salt of 1-phenylnitroethane with sulfuric acid to acetophenone. Reaction mechanism The reaction mechanism starting from the nitronate salt as the resonance structures 1a and 1b is depicted below: The salt is protonated forming the nitronic acid 2 (in some cases these nitronates have been isolated) and once more to the iminium ion 3. This intermediate is attacked by water in a nucleophilic addi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
