Names | |||
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Preferred IUPAC name Dioxirane | |||
Systematic IUPAC name Dioxacyclopropane | |||
Other names 1,2-Dioxacyclopropane Methylene peroxide Peroxymethane | |||
Identifiers | |||
3D model (JSmol) | |||
ChemSpider | |||
PubChem CID | |||
CompTox Dashboard (EPA) | |||
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Properties | |||
CH2O2 | |||
Molar mass | 46.03 g/mol | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
In chemistry, dioxirane (systematically named dioxacyclopropane, also known as methylene peroxide or peroxymethane) is an organic compound with formula CH
2O
2. The molecule consists of a ring with one methylene and two oxygen atoms. It is of interest as the smallest cyclic organic peroxide, but otherwise it is of little practical value.
Dioxirane is highly unstable and the majority of studies of it have been computational; it has been detected during the low temperature (–196 °C) reaction of ethylene and ozone, [1] although even at these temperatures such a mixture can be explosive. [2] Its formation is thought to be radical in nature, preceding via a Criegee intermediate. Microwave analysis has indicated C-H, C-O and O-O bond lengths of 1.090, 1.388 and 1.516 Å respectively. [2] The very long and weak O-O bond (c.f. hydrogen peroxide O-O = 1.47 Å) is the origin of its instability.
Beyond the parent dioxirane, which is mainly of theoretical interest, more common dioxiranes are dimethyldioxirane (DMD or DMDO) and trifluoromethyl-methyldioxirane (TFD). DMDO and the still more reactive methyl(trifluoromethyl)dioxirane have seen some use in organic synthesis, [3] These dioxiranes may be produced through the action of KHSO5 on carbonyl compounds. Because of their low-lying σ*O-O orbital, they are highly electrophilic oxidants and react with unsaturated functional groups, Y-H bonds (yielding oxygen insertion products), and heteroatoms. [4] (1)
Dioxiranes are intermediate in the Shi epoxidation reaction. The latter is effective for chemoselective oxidations of C-H and Si-H bonds. [5] Although this class of reagents is most famous for the epoxidation of alkenes, dioxiranes have been used extensively for other kinds of oxidations as well.
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 and is thermodynamically stable (ΔH° = –104 kcal/mol). [6] [7] Dimesityldioxirane is another relatively stable derivative which has been characterized by X-ray crystallography. [8]
In organic chemistry, an epoxide is a cyclic ether, where the ether forms a three-atom ring: two atoms of carbon and one atom of oxygen. This triangular structure has substantial ring strain, making epoxides highly reactive, more so than other ethers. They are produced on a large scale for many applications. In general, low molecular weight epoxides are colourless and nonpolar, and often volatile.
In organic chemistry, ozonolysis is an organic reaction where the unsaturated bonds are cleaved with ozone. Multiple carbon–carbon bond are replaced by carbonyl groups, such as aldehydes, ketones, and carboxylic acids. The reaction is predominantly applied to alkenes, but alkynes and azo compounds are also susceptible to cleavage. The outcome of the reaction depends on the type of multiple bond being oxidized and the work-up conditions.
Oxygen fluorides are compounds of elements oxygen and fluorine with the general formula OnF2, where n = 1 to 6. Many different oxygen fluorides are known:
Singlet oxygen, systematically named dioxygen(singlet) and dioxidene, is a gaseous inorganic chemical with the formula O=O (also written as 1
[O
2] or 1
O
2), which is in a quantum state where all electrons are spin paired. It is kinetically unstable at ambient temperature, but the rate of decay is slow.
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 RO•. Thus, organic peroxides are useful as initiators for some types of polymerization, such as the acrylic, unsaturated polyester, and vinyl ester 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.
Potassium peroxymonosulfate is widely used as an oxidizing agent, for example, in pools and spas. It is the potassium salt of peroxymonosulfuric acid. Potassium peroxymonosulfate per se is rarely encountered. It is often confused with the triple salt 2KHSO5·KHSO4·K2SO4, known as Oxone.
The Baeyer–Villiger oxidation is an organic reaction that forms an ester from a ketone or a lactone from a cyclic ketone, using peroxyacids or peroxides as the oxidant. The reaction is named after Adolf von Baeyer and Victor Villiger who first reported the reaction in 1899.
Hydroperoxides or peroxols are compounds of the form ROOH, where R stands for any group, typically organic, which contain the hydroperoxy functional group. Hydroperoxide also refers to the hydroperoxide anion and its salts, and the neutral hydroperoxyl radical (•OOH) consist of an unbond hydroperoxy group. When R is organic, the compounds are called organic hydroperoxides. Such compounds are a subset of organic peroxides, which have the formula ROOR. Organic hydroperoxides can either intentionally or unintentionally initiate explosive polymerisation in materials with unsaturated chemical bonds.
The Shi epoxidation is a chemical reaction described as the asymmetric epoxidation of alkenes with oxone and a fructose-derived catalyst (1). This reaction is thought to proceed via a dioxirane intermediate, generated from the catalyst ketone by oxone. 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.
Trioxidane, also called hydrogen trioxide is an inorganic compound with the chemical formula H[O]
3H. It is one of the unstable hydrogen polyoxides. In aqueous solutions, trioxidane decomposes to form water and singlet oxygen:
Hypofluorous acid, chemical formula HOF, is the only known oxyacid of fluorine and the only known oxoacid in which the main atom gains electrons from oxygen to create a negative oxidation state. The oxidation state of the oxygen in this acid is 0, while its valence is 2. It is also the only hypohalous acid that can be isolated as a solid. HOF is an intermediate in the oxidation of water by fluorine, which produces hydrogen fluoride, oxygen difluoride, hydrogen peroxide, ozone and oxygen. HOF is explosive at room temperature, forming HF and O2:
The chemical substance 1,2-dioxetane is a heterocyclic, organic compound with formula C2O2H4, containing a ring of two adjacent oxygen atoms and two adjacent carbon atoms. It is therefore an organic peroxide, and can be viewed as a dimer of formaldehyde.
Dimethyldioxirane (DMDO) is the organic compound with the formula (CH3)2CO2. It is the dioxirane derived from acetone and can be considered as a monomer of acetone peroxide. It is a powerful selective oxidizing agent that finds some 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.
Oxidation with dioxiranes refers to the introduction of oxygen into organic substrates using dioxiranes. Dioxiranes are well known for epoxidations. Dioxiranes oxidize other unsaturated functionality, heteroatoms, and alkane C-H bonds. Dioxiranes are metal-free oxidants.
An oxaziridine is an organic molecule that features a three-membered heterocycle containing oxygen, nitrogen, and carbon. In their largest application, oxaziridines are intermediates in the industrial production of hydrazine. Oxaziridine derivatives are also used as specialized reagents in organic chemistry for a variety of oxidations, including alpha hydroxylation of enolates, epoxidation and aziridination of olefins, and other heteroatom transfer reactions. Oxaziridines also serve as precursors to nitrones and participate in [3+2] cycloadditions with various heterocumulenes to form substituted five-membered heterocycles. Chiral oxaziridine derivatives effect asymmetric oxygen transfer to prochiral enolates as well as other substrates. Some oxaziridines also have the property of a high barrier to inversion of the nitrogen, allowing for the possibility of chirality at the nitrogen center.
The White–Chen catalyst is an Iron-based coordination complex named after Professor M. Christina White and her graduate student Mark S. Chen. The catalyst is used along with hydrogen peroxide and acetic acid additive to oxidize aliphatic sp3 C-H bonds in organic synthesis. The catalyst is the first to allow for preparative and predictable aliphatic C–H oxidations over a broad range of organic substrates. Oxidations with the catalyst have proven to be remarkably predictable based on sterics, electronics, and stereoelectronics allowing for aliphatic C–H bonds to be thought of as a functional group in the streamlining of organic synthesis.
In organic chemistry, alkenyl peroxides are organic peroxides bearing an alkene residue directly at the peroxide group, resulting in the general formula R2C=C(R)OOR. They have very weak O-O bonds and are thus generally unstable compounds.
Methyldioxirane is an organic chemical consisting of a methyl group as substituent on a dioxirane ring. It is a highly unstable structure that has been proposed as part of a decomposition reaction of acetaldehyde oxide, the Criegee intermediate during some ozonolysis reactions. The methyl group helps reduce the rate of ring-opening of the dioxirane, but it does not become usefully stable until a second substient is present as in the structure of dimethyldioxirane.
Difluorodioxirane (CF2O2) is a rare, stable member of the dioxirane family, known for a single oxygen-oxygen bond (O-O). Unlike most dioxiranes that decompose quickly, difluorodioxirane is surprisingly stable at room temperature, making it potentially useful for further research and applications.
Dimesityldioxirane is a substituted dioxirane with two mesityl groups attached to the dioxirane carbon. It is a colorless crystalline substance stable in its solid state around -20 °C.