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Bromohydrin
In organic chemistry a halohydrin (also a haloalcohol or β-halo alcohol) is a functional group in which a halogen and a hydroxyl are bonded to adjacent carbon atoms, which otherwise bear only hydrogen or hydrocarbyl groups (e.g. 2-chloroethanol, 3-chloropropane-1,2-diol). The term only applies to saturated motifs, as such compounds like 2-chlorophenol would not normally be considered halohydrins. Megatons of some chlorohydrins, e.g. propylene chlorohydrin, are produced annually as precursors to polymers. Halohydrins may be categorized as chlorohydrins, bromohydrins, fluorohydrins or iodohydrins depending on the halogen present. Synthesis From alkenes Halohydrins are usually prepared by treatment of an alkene with a halogen, in the presence of water. The reaction is a form of electrophilic addition, similar to the halogen addition reaction and proceeds with anti addition, leaving the newly added X and OH groups in a trans configuration. The chemical equation for the conversion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halohydrin
In organic chemistry a halohydrin (also a haloalcohol or β-halo alcohol) is a functional group in which a halogen and a hydroxyl are bonded to adjacent carbon atoms, which otherwise bear only hydrogen or hydrocarbyl groups (e.g. 2-chloroethanol, 3-chloropropane-1,2-diol). The term only applies to saturated motifs, as such compounds like 2-chlorophenol would not normally be considered halohydrins. Megatons of some chlorohydrins, e.g. propylene chlorohydrin, are produced annually as precursors to polymers. Halohydrins may be categorized as chlorohydrins, bromohydrins, fluorohydrins or iodohydrins depending on the halogen present. Synthesis From alkenes Halohydrins are usually prepared by treatment of an alkene with a halogen, in the presence of water. The reaction is a form of electrophilic addition, similar to the halogen addition reaction and proceeds with anti addition, leaving the newly added X and OH groups in a trans configuration. The chemical equation for the conversion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-Bromosuccinimide
''N''-Bromosuccinimide or NBS is a chemical reagent used in radical substitution, electrophilic addition, and electrophilic substitution reactions in organic chemistry. NBS can be a convenient source of Br•, the bromine radical. Preparation NBS is commercially available. It can also be synthesized in the laboratory. To do so, sodium hydroxide and bromine are added to an ice-water solution of succinimide. The NBS product precipitates and can be collected by filtration. Crude NBS gives better yield in the Wohl-Ziegler reaction. In other cases, impure NBS (slightly yellow in color) may give unreliable results. It can be purified by recrystallization from 90 to 95 °C water (10 g of NBS for 100 mL of water). Reactions Addition to alkenes NBS will react with alkenes 1 in aqueous solvents to give bromohydrins 2. The preferred conditions are the portionwise addition of NBS to a solution of the alkene in 50% aqueous DMSO, DME, THF, or ''tert''-butanol at 0 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Functional Group
In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest of the molecule's composition. This enables systematic prediction of chemical reactions and behavior of chemical compounds and the design of chemical synthesis. The reactivity of a functional group can be modified by other functional groups nearby. Functional group interconversion can be used in retrosynthetic analysis to plan organic synthesis. A functional group is a group of atoms in a molecule with distinctive chemical properties, regardless of the other atoms in the molecule. The atoms in a functional group are linked to each other and to the rest of the molecule by covalent bonds. For repeating units of polymers, functional groups attach to their nonpolar core of carbon atoms and thus add chemical character to carbon chains. Fun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NBS Bromohydrin Formation Scheme
NBS may refer to: Business * National Bank of Samoa * National Bank of Serbia * National Bank of Slovakia * National Book Store, in the Philippines * Nationwide Building Society, UK * NBS (Natal Building Society), former bank in South Africa * NBS Bank, Malawi * Nelson Building Society, New Zealand * Newcastle Building Society, UK Science and technology * Nature-based solutions, use of nature for addressing societal challenges * ''N''-Bromosuccinimide, a chemical reagent * Newborn screening, a series of medical tests given to newborn babies * Nijmegen breakage syndrome, a genetic medical condition Schools * National Broadcasting School, UK * NUST Business School, of the National University of Sciences and Technology, Pakistan Telecommunications * Nagano Broadcasting Systems, Japan * National Broadcasting Service, former name of National Broadcasting Network (Trinidad and Tobago) * National Broadband Plan (United States) * NBS Television (Uganda) * Nippon Broadcasting Syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diazotization
Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halide. General properties and reactivity Arenediazonium cations and related species According to X-ray crystallography the linkage is linear in typical diazonium salts. The bond distance in benzenediazonium tetrafluoroborate is 1.083(3) Å, which is almost identical to that for dinitrogen molecule (N≡N). The linear free energy constants σm and σp indicate that the diazonium group is strongly electron-withdrawing. Thus, the diazonio-substituted phenols and benzoic acids have greatly reduced p''K''a values compared to their unsubstituted counterparts. The p''K''a of phenolic proton of 4-hydroxybenzenediazonium is 3.4, versus 9.9 for phenol itself. In other words, the diazonium group lowers the p''K''a (enhances the acidity) by a million-fold. The stabil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enantiomerically
In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical antipode – is one of two stereoisomers that are non-superposable onto their own mirror image. Enantiomers are much like one's right and left hands, when looking at the same face, they cannot be superposed onto each other. No amount of reorientation will allow the four unique groups on the chiral carbon (see Chirality (chemistry)) to line up exactly. The number of stereoisomers a molecule has can be determined by the number of chiral carbons it has. Stereoisomers include both enantiomers and diastereomers. Diastereomers, like enantiomers, share the same molecular formula and are non-superposable onto each other however, they are not mirror images of each other. A molecule with chirality rotates plane-polarized light. A mixture of equals a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propionyl Chloride
Propionyl chloride (also propanoyl chloride) is the organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. T ... with the formula CH3CH2C(O)Cl. It is the acyl chloride derivative of propionic acid. It undergoes the characteristic reactions of acyl chlorides. It is a colorless, corrosive, volatile liquid. It is used as a reagent for organic synthesis. In derived chiral amides and esters, the methylene protons are diastereotopic. Synthesis Propionyl chloride is industrially produced by chlorination of propionic acid with phosgene: :CH3CH2CO2H + COCl2 → CH3CH2COCl + HCl + CO2 References {{reflist, 30em Acyl chlorides Reagents for organic chemistry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hell–Volhard–Zelinsky Halogenation
The Hell–Volhard–Zelinsky halogenation reaction is a chemical transformation that involves the halogenation of a carboxylic acid at the α carbon. For this reaction to occur the α carbon must bear at least one proton. The reaction is named after the German chemists Carl Magnus von Hell (1849–1926) and Jacob Volhard (1834–1910) and the Russian chemist Nikolay Zelinsky (1861–1953). : An example of the Hell–Volhard–Zelinsky reaction can be seen in the preparation of alanine from propionic acid. In the first step, a combination of bromine and phosphorus tribromide (catalyst) is used in the Hell–Volhard–Zelinsky reaction to prepare 2-bromopropanoic acid, which in the second step is converted to a racemic mixture of the amino acid product by ammonolysis. :: Mechanism The reaction is initiated by addition of a catalytic amount of PBr3, after which one molar equivalent of Br2 is added. : PBr3 replaces the carboxylic OH with a bromide, resulting in a carboxyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithium Aluminium Hydride
Lithium aluminium hydride, commonly abbreviated to LAH, is an inorganic compound with the chemical formula Li Al H4. It is a white solid, discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters, carboxylic acids, and amides. The solid is dangerously reactive toward water, releasing gaseous hydrogen (H2). Some related derivatives have been discussed for hydrogen storage. Properties, structure, preparation LAH is a colourless solid but commercial samples are usually gray due to contamination. This material can be purified by recrystallization from diethyl ether. Large-scale purifications employ a Soxhlet extractor. Commonly, the impure gray material is used in synthesis, since the impurities are innocuous and can be easily separated from the organic products. The pure powdered material is pyrophoric, but not its large crystals. Some commercial materials contain mineral oil to in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethylene Oxide
Ethylene oxide is an organic compound with the chemical formula, formula . It is a cyclic ether and the simplest epoxide: a three-membered Ring (chemistry), ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless and flammable gas with a faintly sweet odor. Because it is a strained ring, ethylene oxide easily participates in a number of addition reactions that result in ring-opening. Ethylene oxide is isomeric with acetaldehyde and with vinyl alcohol. Ethylene oxide is industrially produced by oxidation of ethylene in the presence of silver catalyst. The reactivity that is responsible for many of ethylene oxide's hazards also makes it useful. Although too dangerous for direct household use and generally unfamiliar to consumers, ethylene oxide is used for making many consumer products as well as non-consumer chemicals and intermediates. These products include detergents, thickeners, solvents, plastics, and various organic chemicals such as ethylene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-Chloroethanol
2-Chloroethanol (also called ethylene chlorohydrin or glycol chlorohydrin) is an organic chemical compound with the chemical formula HOCH2CH2Cl and the ''simplest'' beta-halohydrin (chlorohydrin). This colorless liquid has a pleasant ether-like odor. It is miscible with water. The molecule is bifunctional, consisting of both an alkyl chloride and an alcohol functional group. Synthesis and applications 2-Chloroethanol is produced by treating ethylene with hypochlorous acid: : 2-Chloroethanol was once produced on a large scale as a precursor to ethylene oxide: : :HOCH2CH2Cl + NaOH → C2H4O + NaCl + H2O This application has been supplanted by the more economic direct oxidation of ethylene. Otherwise chloroethanol is still used in the production of pharmaceuticals, biocides, and plasticizers. Many of these applications entail its use in installing 2-hydroxyethyl groups. Several dyes are prepared by the alkylation of aniline derivatives with chloroethanol. It is also used for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
