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Sulfonated Polystyrene
In organic chemistry, aromatic sulfonation is a reaction in which a hydrogen atom on an arene is replaced by a sulfonic acid () group. Together with nitration and chlorination, aromatic sulfonation is a widely used electrophilic aromatic substitutions. Aryl sulfonic acids are used as detergents, dye, and drugs. : Stoichiometry and mechanism Typical conditions involve heating the aromatic compound with sulfuric acid: : Sulfur trioxide or its protonated derivative is the actual electrophile in this electrophilic aromatic substitution. To drive the equilibrium, dehydrating agents such as thionyl chloride can be added: : Historically, mercurous sulfate has been used to catalyze the reaction. Chlorosulfuric acid is also an effective agent: : In contrast to aromatic nitration and most other electrophilic aromatic substitutions this reaction is reversible. Sulfonation takes place in concentrated acidic conditions and desulfonation is the mode of action in a dilute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Chemistry
Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University Press. pp. 1–15. . Study of structure determines their structural formula. Study of properties includes Physical property, physical and Chemical property, chemical properties, and evaluation of Reactivity (chemistry), chemical reactivity to understand their behavior. The study of organic reactions includes the organic synthesis, chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical (in silico) study. The range of chemicals studied chemistry includes hydrocarbons (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercurous Sulfate
Mercury is a chemical element; it has symbol Hg and atomic number 80. It is commonly known as quicksilver. A heavy, silvery d-block element, mercury is the only metallic element that is known to be liquid at standard temperature and pressure; the only other element that is liquid under these conditions is the halogen bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature. Mercury occurs in deposits throughout the world mostly as cinnabar ( mercuric sulfide). The red pigment vermilion is obtained by grinding natural cinnabar or synthetic mercuric sulfide. Exposure to mercury and mercury-containing organic compounds is toxic to the nervous system, immune system and kidneys of humans and other animals; mercury poisoning can result from exposure to water-soluble forms of mercury (such as mercuric chloride or methylmercury) either directly or through mechanisms of biomagnification. Mercury is used in thermometers, barometers, manometers, sphy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piria Reaction
Piria may refer to: * Piria, a village in the commune Argetoaia Argetoaia is a commune in Dolj County, Oltenia, Romania Romania is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, ..., Dolj County, Romania * Piriá River (Pará River), a tributary of the Pará River in Brazil * Piriá River (Eastern Pará), a river in the extreme east of the state of Pará, Brazil, that flows into the Atlantic Ocean * Raffaele Piria, a 19th-century Italian chemist **the Piria reaction of aromatic nitro compounds * Vicky Piria, an Italian racing driver * Piria, termine dialettale friulano e bisiaco (Friuli-Venezia Giulia) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of The American Chemical Society
The ''Journal of the American Chemical Society'' (also known as JACS) is a weekly peer-reviewed scientific journal that was established in 1879 by the American Chemical Society. The journal has absorbed two other publications in its history, the ''Journal of Analytical and Applied Chemistry'' (July 1893) and the ''American Chemical Journal'' (January 1914). It covers all fields of chemistry. Since 2021, the editor-in-chief is Erick M. Carreira (ETH Zurich). In 2014, the journal moved to a hybrid open access publishing model. Abstracting and indexing The journal is abstracted and indexed in: According to the ''Journal Citation Reports'', the journal has a 2023 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a type of journal ranking. Journals with higher impact factor values are considered more prestigious or important within their field. The Impact Factor of a journa ... of 14.4. Editors-in-chief The following people are or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitro Group Reduction
Nitro may refer to: Chemistry *Nitrogen, a chemical element and a gas except at very low temperatures, with which many compounds are formed: **Nitro compound, an organic compound containing one or more nitro functional groups, -NO2 ** Nitro ligand in coordination chemistry **Nitroalkene, a functional group combining the functionality of an alkene and nitro group **Nitrocellulose, or cellulose nitrate, an extremely flammable chemical compound **Nitroglycerin, or glyceryl trinitrate, an explosive chemical compound **Nitromethane, a simple organic nitro compound with the formula ***Nitro fuel, a fuel containing nitromethane and methanol **** Nitro engine, an engine powered with nitro fuel used in some radio-controlled model cars, aircraft etc. People * Danny Lee Clark (born 1964), known as "Nitro" on the original ''American Gladiators'' television show *Harry Aikines-Aryeetey (born 1988), known as "Nitro" on the UK ''Gladiators'' television show *John Morrison (wrestler) (born 1979) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bisulfite
The bisulfite ion (IUPAC-recommended nomenclature: hydrogensulfite) is the ion . Salts containing the ion are also known as "sulfite lyes". Sodium bisulfite is used interchangeably with sodium metabisulfite (Na2S2O5). Sodium metabisulfite dissolves in water to give a solution of Na+. :Na2S2O5 + H2O → 2Na SO3 Structure The bisulfite anion exists in solution as a mixture of two tautomers. One tautomer has the proton attached to one of the three oxygen atoms. In the second tautomer the proton resides on sulfur. The S-protonated tautomer has ''C''3v symmetry. The O-protonated tautomer has only ''C''s symmetry. Reactions Tautomerization There exist two tautomers of bisulfite. They interconvert readily but can be characterized individually by various spectroscopic methods. They have been observed by 17O NMR spectroscopy: :HSO3− SO2(OH)− ''K'' = 4.9 Acid-base reactions Solutions of bisulfite are typically prepared by treatment of sulfur dioxide with aqueous bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrobenzene
Nitrobenzene is an aromatic nitro compound and the simplest of the nitrobenzenes, with the chemical formula C6H5 NO2. It is a water-insoluble pale yellow oil with an almond-like odor. It freezes to give greenish-yellow crystals. It is produced on a large scale from benzene as a precursor to aniline. In the laboratory, it is occasionally used as a solvent, especially for electrophilic reagents. As confirmed by X-ray crystallography, nitrobenzene is a planar molecule. Production Nitrobenzene is prepared by nitration of benzene with a mixture of concentrated sulfuric acid, water, and nitric acid. This mixture is sometimes called "mixed acid." The production of nitrobenzene is one of the most dangerous processes conducted in the chemical industry because of the exothermicity of the reaction (Δ''H'' = −117 kJ/mol). World capacity for nitrobenzene in 1985 was about 1,700,000 tonnes. The nitration process involves formation of the nitronium ion (NO2+), followed by an e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raffaele Piria
Raffaele Piria (Scilla 20 August 1814 – Turin 18 July 1865) was an Italian chemist from Scilla, who lived in Palmi. He converted the substance Salicin into a sugar and a second component, which on oxidation becomes salicylic acid, a major component of the analgesic drug Aspirin ( acetylsalicylic acid). Other reactions discovered by Piria were the conversion of aspartic acid to malic acid Malic acid is an organic compound with the molecular formula . It is a dicarboxylic acid that is made by all living organisms, contributes to the sour taste of fruits, and is used as a food additive. Malic acid has two stereoisomeric forms ( ... by action of nitrogen dioxide, and the reaction of aromatic nitro compounds with sulfite towards aminosulfonic acids. References {{DEFAULTSORT:Piria, Raffaele Italian chemists People from Scilla, Calabria Scientists from the Kingdom of the Two Sicilies People from Palmi 1814 births 1865 deaths Academic staff of the University of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrophilic Aromatic Directing Groups
In electrophilic aromatic substitution reactions, existing substituent groups on the aromatic ring influence the overall reaction rate or have a directing group, directing effect on positional isomer of the product (chemistry), products that are formed. An electron donating group (EDG) or electron releasing group (ERG, Z in structural formulas) is an atom or functional group that donates some of its electron density into a conjugated system, conjugated π system via resonance (chemistry), resonance (mesomerism) or inductive effects (or induction)—called +M or +I effects, respectively—thus making the π system more nucleophile, nucleophilic. As a result of these electronic effects, an aromatic ring to which such a group is attached is more likely to participate in electrophilic substitution reaction. EDGs are therefore often known as activating groups, though steric effects can interfere with the reaction. An electron withdrawing group (EWG) will have the opposite effect on t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron-withdrawing
An electron-withdrawing group (EWG) is a group or atom that has the ability to draw electron density toward itself and away from other adjacent atoms. This electron density transfer is often achieved by resonance or inductive effects. Electron-withdrawing groups have significant impacts on fundamental chemical processes such as acid-base reactions, redox potentials, and substitution reactions. Consequences of EWGs Effects on Brønsted–Lowry acidity Electron-withdrawing groups exert an " inductive" or "electron-pulling" effect on covalent bonds. The strength of the electron-withdrawing group is inversely proportional to the pKa of the carboxylic acid. : The inductive effect is cumulative: trichloroacetic acid is 1000× stronger than chloroacetic acid. : :The impact of the EWG on pKa decreases with distances from the carboxylic group. For benzoic acids, the effect is quantified by the Hammett equation: :\log \frac = \sigma\rho where :_0 = Reference constant :\sigma = S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protection Group
A protecting group or protective group is introduced into a molecule by chemical modification of a functional group to obtain chemoselectivity in a subsequent chemical reaction. It plays an important role in multistep organic synthesis. In many preparations of delicate organic compounds, specific parts of the molecules cannot survive the required reagents or chemical environments. These parts (functional groups) must be protected. For example, lithium aluminium hydride is a highly reactive reagent that usefully reduces esters to alcohols. It always reacts with carbonyl groups, and cannot be discouraged by any means. When an ester must be reduced in the presence of a carbonyl, hydride attack on the carbonyl must be prevented. One way to do so converts the carbonyl into an acetal, which does not react with hydrides. The acetal is then called a protecting group for the carbonyl. After the hydride step is complete, aqueous acid removes the acetal, restoring the carbonyl. This step is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reversible Reaction
A reversible reaction is a reaction in which the conversion of reactants to products and the conversion of products to reactants occur simultaneously. : \mathit aA + \mathit bB \mathit cC + \mathit dD A and B can react to form C and D or, in the reverse reaction, C and D can react to form A and B. This is distinct from a reversible process in thermodynamics. Weak acids and bases undergo reversible reactions. For example, carbonic acid: : H2CO3 (l) + H2O(l) ⇌ HCO3−(aq) + H3O+(aq). The concentrations of reactants and products in an equilibrium mixture are determined by the analytical concentrations of the reagents (A and B or C and D) and the equilibrium constant, ''K''. The magnitude of the equilibrium constant depends on the Gibbs free energy change for the reaction. So, when the free energy change is large (more than about 30 kJ mol−1), the equilibrium constant is large (log K > 3) and the concentrations of the reactants at equilibrium are very small. Such a reaction i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
