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Ynol
In organic chemistry, an alkynol (shortened to ynol) is an alkyne with a hydroxyl group affixed to one of the two carbon atoms composing the triple bond (). The deprotonated anions of ynols are known as '' ynolates''. An ynol with hydroxyl groups on both sides of its triple bond is known as an ynediol; only one ynediol, acetylenediol, exists. Ynolates Ynolates are chemical compounds with a negatively charged oxygen atom attached to an alkyne functionality. They were first synthesized in 1975 by Schöllkopf and Hoppe via the ''n''-butyllithium fragmentation of 3,4-diphenylisoxazole. Synthetically, they behave as ketene precursors or synthons. Ynol–ketene tautomerism Ynols can interconvert with ketenes, much like enols can with aldehydes and ketones. The ynol tautomer is usually unstable, does not survive long, and changes into the ketene. This is because oxygen is more electronegative than carbon and thus forms stronger bonds. For instance, ethynol quickly inter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethynol
Ethynol (or hydroxyacetylene) is an alkyne–alcohol (ynol) with the formula C2H2O. It is the much-less-stable tautomer of ethenone. At low temperature in a solid argon matrix it is possible to tautomerise ethenone to form ethynol. See also *Ethanol (ethyl alcohol) *Ethenol Vinyl alcohol, also called ethenol (IUPAC name; not ethanol), is the simplest enol. With the formula , it is a labile compound that converts to acetaldehyde. It is not a precursor to polyvinyl alcohol. Synthesis Vinyl alcohol can be formed by t ... (vinyl alcohol) * Acetylenediol References Alkynols {{Alcohol-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ynolate
Ynolates are chemical compounds with a negatively charged oxygen attached to an alkyne functionality. They were first synthesized in 1975 by Schöllkopf and Hoppe via the ''n''-butyllithium fragmentation of 3,4-diphenylisoxazole. Synthetically, they behave as ketene precursors or synthons. See also *Enolate In organic chemistry, enolates are organic anions derived from the deprotonation of carbonyl () compounds. Rarely isolated, they are widely used as reagents in the synthesis of organic compounds. Bonding and structure Enolate anions are electr ... References Functional groups {{organic-chemistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylenediol
Acetylenediol, or ethynediol, is a chemical substance with formula HO−C≡C−OH (an ynol). It is the diol of acetylene. Acetylenediol is unstable in the condensed phase, although its tautomer glyoxal (CHO)2 is well known. Detection Acetylenediol was first observed in the gas-phase by mass spectrometry. The compound was later obtained by photolysis of squaric acid in a solid argon matrix at . Derivatives Alkoxide derivatives Like the diol, most simple ether derivatives are labile. Di-tert-butoxyacetylene is however a distillable liquid. Acetylenediolate salts Salts of the acetylenediolate (ethynediolate) dianion −O−C≡C−O− are known. They are not however prepared from ethynediol, but by the reduction of carbon monoxide. Potassium acetylenediolate (K2C2O2) was first obtained by Liebig in 1834, from the reaction of carbon monoxide with metallic potassium;Justus Liebig (1834), Annalen der Chemie und Pharmacie, volume 11, p. 182. Cited by Raymond N. Vrtis et al. ... [...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, hypo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldehyde
In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl group. Aldehydes are common and play important roles in the technology and biological spheres. Structure and bonding Aldehydes feature a carbon center that is connected by a double bond to oxygen and a single bond to hydrogen and single bond to a third substituent, which is carbon or, in the case of formaldehyde, hydrogen. The central carbon is often described as being sp2-Orbital hybridisation, hybridized. The aldehyde group is somewhat polar molecule, polar. The C=O bond length is about 120-122 picometers. Physical properties and characterization Aldehydes have properties that are diverse and that depend on the remainder of the molecule. Smaller aldehydes are more soluble in water, formaldehyde and acetaldehyde completely so. The volatile ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethenone
In organic chemistry, ethenone is the formal name for ketene, an organic compound with formula or . It is the simplest member of the ketene class. It is an important reagent for acetylations. Properties Ethenone is a highly reactive gas (at standard conditions) and has a sharp irritating odour. It is only reasonably stable at low temperatures (−80 °C). It must therefore always be prepared for each use and processed immediately, otherwise a dimerization to diketene occurs or it reacts to polymers that are difficult to handle. The polymer content formed during the preparation is reduced, for example, by adding sulfur dioxide to the ketene gas. Because of its cumulative double bonds, ethenone is highly reactive and reacts in an addition reaction H-acidic compounds to the corresponding acetic acid derivatives. It does for example react with water to acetic acid or with primary or secondary amines to the corresponding acetamides. Preparation In industrial chemistry, k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethenone
In organic chemistry, ethenone is the formal name for ketene, an organic compound with formula or . It is the simplest member of the ketene class. It is an important reagent for acetylations. Properties Ethenone is a highly reactive gas (at standard conditions) and has a sharp irritating odour. It is only reasonably stable at low temperatures (−80 °C). It must therefore always be prepared for each use and processed immediately, otherwise a dimerization to diketene occurs or it reacts to polymers that are difficult to handle. The polymer content formed during the preparation is reduced, for example, by adding sulfur dioxide to the ketene gas. Because of its cumulative double bonds, ethenone is highly reactive and reacts in an addition reaction H-acidic compounds to the corresponding acetic acid derivatives. It does for example react with water to acetic acid or with primary or secondary amines to the corresponding acetamides. Preparation In industrial chemistry, k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Covalent Bond
A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding. For many molecules, the sharing of electrons allows each atom to attain the equivalent of a full valence shell, corresponding to a stable electronic configuration. In organic chemistry, covalent bonding is much more common than ionic bonding. Covalent bonding also includes many kinds of interactions, including σ-bonding, π-bonding, metal-to-metal bonding, agostic interactions, bent bonds, three-center two-electron bonds and three-center four-electron bonds. The term ''covalent bond'' dates from 1939. The prefix ''co-'' means ''jointly, associated in action, partnered to a lesser degree, '' etc.; thus a "co-valent bond", in essence, means that the atoms share "valence" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bond Energy
In chemistry, bond energy (''BE''), also called the mean bond enthalpy or average bond enthalpy is the measure of bond strength in a chemical bond. IUPAC defines bond energy as the average value of the gas-phase bond-dissociation energy (usually at a temperature of 298.15 K) for all bonds of the same type within the same chemical species. The bond dissociation energy (enthalpy) is also referred to as bond disruption energy, bond energy, bond strength, or binding energy (abbreviation: ''BDE'', ''BE'', or ''D''). It is defined as the standard enthalpy change of the following fission: R - ''X'' → R + ''X''. The ''BDE'', denoted by Dº(R - ''X''), is usually derived by the thermochemical equation, : \begin \mathrmX) \ = \Delta H^\circ_f\mathrm + \Delta H^\circ_f(X) - \Delta H^\circ_f(\mathrmX) \end The enthalpy of formation Δ''Hf''º of a large number of atoms, free radicals, ions, clusters and compounds is available from the websites of NIST, NASA, CODATA, and IUPAC. Most aut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
