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Ethers
In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be classified into two varieties: if the alkyl or aryl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether" (). Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin. Structure and bonding Ethers feature bent C–O–C linkages. In dimethyl ether, the bond angle is 111° and C–O distances are 141 pm. The barrier to rotation about the C–O bonds is low. The bonding of oxygen in ethers, alcohols, and water is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enol Ether
In organic chemistry an enol ether is an alkene with an alkoxy substituent. The general structure is R2C=CR-OR where R = H, alkyl or aryl. A common subfamily of enol ethers are vinyl ethers, with the formula ROCH=CH2. Important enol ethers include the reagent 3,4-dihydropyran and the monomers methyl vinyl ether and ethyl vinyl ether. Reactions and uses Akin to enamines, enol ethers are electron-rich alkenes by virtue of the electron-donation from the heteroatom via pi-bonding. Enol ethers have oxonium ion character. By virtue of their bonding situation, enol ethers display distinctive reactivity. In comparison with simple alkenes, enol ethers exhibit enhanced susceptibility to attack by electrophiles such as Bronsted acids. Similarly, they undergo inverse demand Diels-Alder reactions. The reactivity of enol ethers is highly dependent on the presence of substituents alpha to oxygen. The vinyl ethers are susceptible to polymerization to give polyvinyl ethers. Some vinyl ethers al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methoxy
In organic chemistry, a methoxy group is the functional group consisting of a methyl group bound to oxygen. This alkoxy group has the formula . On a benzene ring, the Hammett equation classifies a methoxy substituent at the ''para'' position as an electron-donating group, but as an electron-withdrawing group if at the ''meta'' position. At the ''ortho'' position, steric effects are likely to cause a significant alteration in the Hammett equation prediction which otherwise follows the same trend as that of the ''para'' position. Occurrence The simplest of methoxy compounds are methanol and dimethyl ether. Other methoxy ethers include anisole and vanillin. Many alkoxides contain methoxy groups, e.g. tetramethyl orthosilicate and titanium methoxide. Such compounds are often classified as methoxides. Esters with a methoxy group can be referred to as methyl esters, and the —COOCH3 substituent is called a methoxycarbonyl. Biosynthesis In nature, methoxy groups are found on nucleosi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solvent
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for polar molecules and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within the cell. The quantity of solute that can dissolve in a specific volume of solvent varies with temperature. Major uses of solvents are in paints, paint removers, inks, and dry cleaning. Specific uses for organic solvents are in dry cleaning (e.g. tetrachloroethylene); as paint thinners (toluene, turpentine); as nail polish removers and solvents of glue (acetone, methyl acetate, ethyl acetate); in spot removers (hexane, petrol ether); in detergents ( citrus terpenes); and in perfumes (ethanol). Solvents find various applications in chemical, pharmaceutical, oil, and gas industries, including in chemical syn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diethyl Ether
Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable liquid. It is commonly used as a solvent in laboratories and as a starting fluid for some engines. It was formerly used as a general anesthetic, until non-flammable drugs were developed, such as halothane. It has been used as a recreational drug to cause intoxication. Production Most diethyl ether is produced as a byproduct of the vapor-phase hydration of ethylene to make ethanol. This process uses solid-supported phosphoric acid catalysts and can be adjusted to make more ether if the need arises. Vapor-phase dehydration of ethanol over some alumina catalysts can give diethyl ether yields of up to 95%. Diethyl ether can be prepared both in laboratories and on an industrial scale by the acid ether synthesis. Ethanol is mixed with a stro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ketones
In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bond C=O). The simplest ketone is acetone (where R and R' is methyl), with the formula . Many ketones are of great importance in biology and in industry. Examples include many sugars (ketoses), many steroids (e.g., testosterone), and the solvent acetone. Nomenclature and etymology The word ''ketone'' is derived from ''Aketon'', an old German word for ''acetone''. According to the rules of IUPAC nomenclature, ketone names are derived by changing the suffix ''-ane'' of the parent alkane to ''-anone''. Typically, the position of the carbonyl group is denoted by a number, but traditional nonsystematic names are still generally used for the most important ketones, for example acetone and benzophenone. These nonsystematic names are considered ret ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aromatic
In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to saturated compounds having single bonds, and other geometric or connective non-cyclic arrangements with the same set of atoms. Aromatic rings are very stable and do not break apart easily. Organic compounds that are not aromatic are classified as aliphatic compounds—they might be cyclic, but only aromatic rings have enhanced stability. The term ''aromaticity'' with this meaning is historically related to the concept of having an aroma, but is a distinct property from that meaning. Since the most common aromatic compounds are derivatives of benzene (an aromatic hydrocarbon common in petroleum and its distillates), the word ''aromatic'' occasionally refers informally to benzene derivatives, and so it was first defined. Nevertheless, many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aniseed
Anise (; '), also called aniseed or rarely anix is a flowering plant in the family Apiaceae native to Eurasia. The flavor and aroma of its seeds have similarities with some other spices and herbs, such as star anise, fennel, licorice, and tarragon. It is widely cultivated and used to flavor food, candy, and alcoholic drinks, especially around the Mediterranean. Description Anise is an herbaceous annual plant growing to or more. The leaves at the base of the plant are simple, long and shallowly lobed, while leaves higher on the stems are feathery pinnate, divided into numerous small leaflets. The flowers are either white or yellow, approximately in diameter, produced in dense umbels. The fruit is an oblong dry schizocarp, long, usually called "aniseed".Anise (''Pimpinella anisum'' L.) from Gernot Katzer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methoxyethane
Methoxyethane, also known as ethyl methyl ether, is a colorless gaseous ether. Unlike the related dimethyl ether and diethyl ether Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable liq ..., which are widely used and studied, this mixed alkyl ether has no current applications. Its utility as an anesthetic and solvent have been investigated. References Dialkyl ethers Ether solvents {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUPAC Nomenclature
A chemical nomenclature is a set of rules to generate systematic names for chemical compounds. The nomenclature used most frequently worldwide is the one created and developed by the International Union of Pure and Applied Chemistry (IUPAC). The IUPAC's rules for naming organic and inorganic compounds are contained in two publications, known as the ''Blue Book''. . and the '' Red Book'',. respectively. A third publication, known as the '' Green Book'',. recommends the use of symbols for physical quantities (in association with the IUPAP), while a fourth, the ''Gold Book'',''Compendium of Chemical Terminology, IMPACT Recommendations (2nd Ed.)'', Oxford:Blackwell Scientific Publications. (1997) defines many technical terms used in chemistry. Similar compendia exist for biochemistry''Biochemical Nomenclature and Related Documents'', London: Portland Press, 1992. (the ''White Book'', in association with the IUBMB), analytical chemistry (the '' Orange Book''), macromolecular chemistr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Di-tert-butoxyacetylene
Di-''tert''-butoxyacetylene is the organic compound with the formula (CH3)3COC≡COC(CH3)3. A pale yellow liquid, it is one of the more common dialkoxyacetylenes. Most other dialkoxyacetylenes are very labile. For example, dimethoxyacetylene polymerizes within seconds at 0 °C. Di-''tert''-butoxyacetylene can be prepared from 1,4-dioxane 1,4-Dioxane () is a heterocyclic organic compound, classified as an ether. It is a colorless liquid with a faint sweet odor similar to that of diethyl ether. The compound is often called simply dioxane because the other dioxane isomers ( 1,2- ... in a multistep procedure.{{cite journal , first1=Anna, last1=Bou, first2=Miquel A. , last2=Pericàs, first3=Antoni, last3=Riera, first4=Fèlix, last4=Serratosa, doi=10.15227/orgsyn.065.0068, title=Dialkoxyacetylenes: Di-''tert''-butoxyethyne, A Valuable Synthetic Intermediate, journal=Organic Syntheses, year=1987, volume=65, page=68 References Tert-butyl compounds Alkyne derivatives ... [...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] |
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