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Acyloin Condensation
Acyloin condensation is a Redox, reductive coupling of two carboxylic esters using Impurity, impure metallic sodium to yield an α-hydroxyketone, also known as an acyloin. The reaction is most successful when ''R'' is Aliphatic compound, aliphatic and Saturated compound, saturated, and typically performed with a silyl chloride reactant to Trapping (chemistry), trap the product as a Silyl enol ether, disilyl enediol ether. The reaction is performed in aprotic solvents with a high boiling point, such as benzene and toluene, in an Inert atmosphere technique, oxygen-free atmosphere (as even traces of oxygen interfere with the reaction path and reduce the yield). Protic solvents effect the Bouveault-Blanc reduction, Bouveault-Blanc ester reduction rather than condensation. Independent of Concentration, dilution, acyloin condensation of a Diesters, diester favours intramolecular cyclisation (for all but the smallest rings) over intermolecular polymerisation. This effect is belie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redox
Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. The oxidation and reduction processes occur simultaneously in the chemical reaction. There are two classes of redox reactions: * Electron transfer, Electron-transfer – Only one (usually) electron flows from the atom, ion, or molecule being oxidized to the atom, ion, or molecule that is reduced. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * Atom transfer – An atom transfers from one Substrate (chemistry), substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously, the oxidation state of oxygen decreases as it accepts electrons r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toluene
Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon with the chemical formula , often abbreviated as , where Ph stands for the phenyl group. It is a colorless, water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...-insoluble liquid with the odor associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) attached to a phenyl group by a single bond. As such, its systematic IUPAC nomenclature of organic chemistry, IUPAC name is methylbenzene. Toluene is predominantly used as an industrial feedstock and a solvent. As the solvent in some types of paint thinner, permanent markers, contact cement and certain types of glue, toluene is sometimes used as a recreational inhalant and has the potential of causin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper Chromite Catalyst
Copper chromite often refers to inorganic compounds with the formula . They are black solids. is a well-defined material. The other copper chromite often is described as . It is used to catalyze reactions in organic chemistry. History Copper chromite was first described in 1908. The catalyst was further developed by Homer Burton Adkins and Wilbur Arthur Lazier, partly based on interrogation of German chemists after World War II in relation to the Fischer–Tropsch process. For this reason it is sometimes referred to as the Adkins catalyst or the Lazier catalyst. Adkins was the first to incorporate barium into the structure, which prevents the catalyst from being reduced to an inactive form during hydrogenation reactions. Chemical structures The stoichiometry of the Laziar or Adkins catalyst is not well defined, thus the structure of their material is not defined either. The oxidation states for the constituent metals in Cu2Cr2O4 are Cu(II) and Cr(III). A variety of compos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogenation
Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to redox, reduce or Saturated and unsaturated compounds, saturate organic compounds. Hydrogenation typically constitutes the addition of pairs of hydrogen atoms to a molecule, often an alkene. Catalysts are required for the reaction to be usable; non-catalytic hydrogenation takes place only at very high temperatures. Hydrogenation reduces Double bond, double and Triple bond, triple bonds in hydrocarbons. Process Hydrogenation has three components, the Saturated and unsaturated compounds, unsaturated substrate, the hydrogen (or hydrogen source) and, invariably, a catalyst. The redox, reduction reaction is carried out at different temperatures and pressures depending upon the substrate and the activity of the catalyst. Related or competing reactions The same cataly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sebacic Acid
Sebacic acid is a naturally occurring dicarboxylic acid with the chemical formula . It is a white flake or powdered solid. ''Sebaceus'' is Latin for tallow candle, ''sebum'' is Latin for tallow, and refers to its use in the manufacture of candles. Sebacic acid is a derivative of castor oil. In the industrial setting, sebacic acid and its homologues such as azelaic acid can be used as a monomer for nylon 610, plasticizers, lubricants, hydraulic fluids, cosmetics, candles, etc. It can be used as a surfactant in the lubricating oil industry to increase the antirust properties of lubricating oils on metals. Production and reactions Sebacic acid is produced from castor oil by cleavage of ricinoleic acid, which is obtained from castor oil. Octanol and glycerin are byproducts. It can also be obtained from decalin via the a hydroperoxide, which rearranges to give a hydroxycyclodecanone, which dehydrates to give cyclodecenone, a precursor to sebacic acid. Sebacic acid has also been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tropolone
Tropolone is an organic compound with the chemical formula . It is a pale yellow solid that is soluble in organic solvents. The compound has been of interest to research chemists because of its unusual electronic structure and its role as a ligand precursor. Although not usually prepared from tropone, it can be viewed as its derivative with a hydroxyl group in the 2-position. Synthesis and reactions Many methods have been described for the synthesis of tropolone. One involves bromination of 1,2-cycloheptanedione with ''N''-bromosuccinimide followed by dehydrohalogenation at elevated temperatures, while another uses acyloin condensation of the ethyl ester of pimelic acid the acyloin again followed by oxidation by bromine. : An alternate route is a +2 cycloaddition of cyclopentadiene with a ketene to give a bicyclo .2.0eptyl structure, followed by hydrolysis and breakage of the fusion bond to give the single ring: : Thy hydroxyl group of tropolone is acidic, having a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intramolecular Acyloin Condensation
Intramolecular describes a process or phenomenon that occurs ''within'' a molecule. It can refer to: *Intramolecular reaction *Intramolecular force An intramolecular force (from Latin ''intra-'' 'within') is any force that binds together the atoms making up a molecule. Intramolecular forces are stronger than the Intermolecular force, intermolecular forces that govern the interactions between ... See also * {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerisation
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many forms of polymerization and different systems exist to categorize them. In chemical compounds, polymerization can occur via a variety of reaction mechanisms that vary in complexity due to the functional groups present in the reactants and their inherent steric effects. In more straightforward polymerizations, alkenes form polymers through relatively simple radical reactions; in contrast, reactions involving substitution at a carbonyl group require more complex synthesis due to the way in which reactants polymerize. As alkenes can polymerize in somewhat straightforward radical reactions, they form useful compounds such as polyethylene and polyvinyl chloride (PVC), which are produced in high tonnages each year due to their usefulness in m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclisation
A cyclic compound (or ring compound) is a term for a chemical compound, compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring (chemistry), ring. Rings may vary in size from three to many atoms, and include examples where all the atoms are carbon (i.e., are alicyclic compound, carbocycles), none of the atoms are carbon (inorganic cyclic compounds), or where both carbon and non-carbon atoms are present (heterocyclic compounds with rings containing both carbon and non-carbon). Depending on the ring size, the bond order of the individual links between ring atoms, and their arrangements within the rings, carbocyclic and heterocyclic compounds may be aromatic compound, aromatic or non-aromatic; in the latter case, they may vary from being fully saturated and unsaturated compounds, saturated to having varying numbers of multiple bonds between the ring atoms. Because of the tremendous diversity allowed, in combination, by the val ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diesters
In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distinctive functional group. Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well (e.g. amides), but not according to the IUPAC. Glycerides are fatty acid esters of glycerol; they are important in biology, being one of the main classes of lipids and comprising the bulk of animal fats and vegetable oils. Lactones are cyclic carboxylic esters; naturally occurring lactones are mainly 5- and 6-membered ring lactones. Lactones contribute to the aroma of fruits, butter, cheese, vegetables like celery and other foods. Esters can be formed from oxoacids (e.g. esters of acetic acid, carbonic acid, sulfuric acid, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concentration
In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', '' molar concentration'', '' number concentration'', and '' volume concentration''. The concentration can refer to any kind of chemical mixture, but most frequently refers to solutes and solvents in solutions. The molar (amount) concentration has variants, such as normal concentration and osmotic concentration. Dilution is reduction of concentration, e.g. by adding solvent to a solution. The verb to concentrate means to increase concentration, the opposite of dilute. Etymology ''Concentration-'', ''concentratio'', action or an act of coming together at a single place, bringing to a common center, was used in post-classical Latin in 1550 or earlier, similar terms attested in Italian (1589), Spanish (1589), English (1606), French (1632). Qualitative description Often in informal, non- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
