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Pentafluorobenzoic Acid
Pentafluorobenzoic acid (PFBA) is an organofluorine compound with the formula C6F5CO2H. It is a white crystalline powder that has a high solubility in water. Its pKa of 1.48 indicates that it is a strong acid.Prakash, G. K. S.; Hu, J. "Pentafluorobenzoic Acid" in ''Encyclopedia of Reagents for Organic Synthesis, e-EROS Encyclopedia of Reagents for Organic Synthesis'', 2005. Preparation Pentafluorobenzoic acid is prepared by treating pentafluorophenyllithium (or pentafluorophenyl Grignard reagent) with carbon dioxide. These reagents are usually prepared in situ from pentafluorobenzene and bromopentafluorobenzene. It arises via the reaction of perfluorotoluene with trifluoroacetic acid and antimony pentafluoride. Substitution reactions Substitution of fluoride occurs typically at the para position. This reaction has been used to anchor the −C6F4CO2H group to surfaces. Magnesium methoxide results in ortho methoxylation. Cleavage of this ether gives tetrafluorosalicylic a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzoic Acid
Benzoic acid () is a white (or colorless) solid organic compound with the formula , whose structure consists of a benzene ring () with a carboxyl () substituent. The benzoyl group is often abbreviated "Bz" (not to be confused with "Bn," which is used for benzyl), thus benzoic acid is also denoted as BzOH, since the benzoyl group has the formula –. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, which was for a long time its only source. Benzoic acid occurs naturally in many plants and serves as an intermediate in the biosynthesis of many secondary metabolites. Salts of benzoic acid are used as food preservatives. Benzoic acid is an important precursor for the industrial synthesis of many other organic substances. The salts and esters of benzoic acid are known as benzoates (). History Benzoic acid was discovered in the sixteenth century. The dry distillation of gum benzoin was first described by Nostradamus (1556), and then by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrobenzoic Acid
Nitrobenzoic acids are derivatives of benzoic acid. Two are commercially important. They are about ten times more acidic than the parent benzoic acid.Takao Maki, Kazuo Takeda "Benzoic Acid and Derivatives" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2002, Wiley-VCH, Weinheim. Nitrobenzoic acid can be prepared through the oxidation of styrene in boiling nitric acid. The salts and esters of nitrobenzoic acids are known as nitrobenzoates. Isomers The three isomers of nitrobenzoic acid are: *2-Nitrobenzoic acid is prepared by oxidation of 2-nitrotoluene. *3-Nitrobenzoic acid is a precursor to 3-aminobenzoic acid, which in turn is used to prepare some dyes. It can be prepared by nitration of benzoic acid. It also can be prepared by treating benzaldehyde under nitration conditions, a process that initially converts the aldehyde to the acid. *4-Nitrobenzoic acid is a precursor to 4-aminobenzoic acid, which is in turn used to prepare the anesthetic procaine Procaine i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxylic Acid
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an Substituent, R-group. The general formula of a carboxylic acid is often written as or , sometimes as with R referring to an organyl group (e.g., alkyl, alkenyl, aryl), or hydrogen, or other groups. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion. Examples and nomenclature Carboxylic acids are commonly identified by their trivial names. They often have the suffix ''-ic acid''. IUPAC-recommended names also exist; in this system, carboxylic acids have an ''-oic acid'' suffix. For example, butyric acid () is butanoic acid by IUPAC guidelines. For nomenclature of complex molecules containing a carboxylic acid, the carboxyl can be considered position one of the parent chain even if there are other substituents, such as 3-chloropropanoic acid. Alternately, it can be named ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organofluorine Compound
Organofluorine chemistry describes the chemistry of organofluorine compounds, organic compounds that contain a carbon–fluorine bond. Organofluorine compounds find diverse applications ranging from oil and water repellents to pharmaceuticals, refrigerants, and reagents in catalysis. In addition to these applications, some organofluorine compounds are pollutants because of their contributions to ozone depletion, global warming, bioaccumulation, and toxicity. The area of organofluorine chemistry often requires special techniques associated with the handling of fluorinating agents. The carbon–fluorine bond Fluorine has several distinctive differences from all other substituents encountered in organic molecules. As a result, the physical and chemical properties of organofluorines can be distinctive in comparison to other organohalogens. # The carbon–fluorine bond is one of the strongest in organic chemistry (an average bond energy around 480 kJ/mol). This is significantly st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encyclopedia Of Reagents For Organic Synthesis
The ''Encyclopedia of Reagents for Organic Synthesis'' is published in print and online by John Wiley & Sons Ltd. The online version is also known as e-EROS. The encyclopedia contains a description of the use of reagents used in organic chemistry. The eight-volume print version includes 3500 alphabetically arranged articles and the online version is regularly updated to include new reagents and catalyst Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...s. References External links *Print version Encyclopedias of science Chemistry books {{encyclopedia-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentafluorobenzene
Pentafluorobenzene is a synthetic organofluoride compound with the molecular formula . The compound consists of a benzene ring substituted with five fluorine atoms. The substance is a colorless liquid with a boiling point similar to that of benzene.''CRC Handbook of Chemistry and Physics'', 90. Edition, CRC Press, Boca Raton, Florida, 2009, , Section 3, ''Physical Constants of Organic Compounds'', p. 3-414. It is prepared by defluorination of highly fluorinated cyclohexanes over hot nickel or iron. Another method involved dehydrofluorination of polyfluorinated cyclohexane using hot aqueous solution of potassium hydroxide. It has been observed as a degradation by-product of the incineration of polytetrafluoroethylene and of biosolids. Safety According to its Safety Data Sheet (SDS), the chemical is highly flammable, and is harmful if swallowed. The SDS states its "toxicological properties have not been fully investigated". Combustion by-products include hydrogen fluoride. Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfluorotoluene
Perfluorotoluene or octafluorotoluene is a chemical which belongs to the class of fluorocarbons, specifically a perfluorocarbon. Fluorocarbons and their derivatives are useful fluoropolymers, refrigerants, solvents, and anesthetics. More specifically, perfluorotoluene is a perfluoroaromatic compound, which is perfluorocarbon containing an aromatic ring. Other examples include hexafluorobenzene and octafluoronaphthalene. Perfluorotoluene is commonly used as industrial solvent and can be prepared by defluorination of perfluoromethylcyclohexane by heating to 500 °C with a nickel or iron catalyst Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick .... References {{reflist Fluorocarbons Halogenated solvents Coolants Trifluoromethyl compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trifluoroacetic Acid
Trifluoroacetic acid (TFA) is a synthetic organofluorine compound with the chemical formula CF3CO2H. It belongs to the subclass of per- and polyfluoroalkyl substances (PFASs) known as ultrashort-chain perfluoroalkyl acids (PFAAs). TFA is not produced biologically or abiotically and is commonly used in organic chemistry for various purposes. It is the most abundant PFAS found in the environment. It is a haloacetic acid, with all three of the acetyl group's hydrogen atoms replaced by fluorine atoms. It is a colorless liquid with a vinegar-like odor. TFA is a stronger acid than acetic acid, having an acid ionisation constant, ''K''a, that is approximately 34,000 times higher, as the highly electronegative fluorine atoms and consequent electron-withdrawing nature of the trifluoromethyl group weakens the oxygen-hydrogen bond (allowing for greater acidity) and stabilises the anionic conjugate base. Synthesis TFA is prepared industrially by the electrofluorination of ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antimony Pentafluoride
Antimony pentafluoride is the inorganic compound with the formula Sb F5. This colorless, viscous liquid is a strong Lewis acid and a component of the superacid fluoroantimonic acid, formed upon mixing liquid HF with liquid SbF5 in 1:1 ratio. It is notable for its strong Lewis acidity and the ability to react with almost all known compounds. Preparation Antimony pentafluoride is prepared by the reaction of antimony pentachloride with anhydrous hydrogen fluoride:Sabina C. Grund, Kunibert Hanusch, Hans J. Breunig, Hans Uwe Wolf "Antimony and Antimony Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2006, Wiley-VCH, Weinheim :SbCl5 + 5 HF → SbF5 + 5 HCl It can also be prepared from antimony trifluoride and fluorine. Structure and chemical reactions In the gas phase, SbF5 adopts a trigonal bipyramidal structure of D3h point group symmetry (see picture). The material adopts a more complicated structure in the liquid and solid states. The liquid contains polymers whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzoic Acids
Benzoic acid () is a white (or colorless) solid organic compound with the formula , whose Chemical structure, structure consists of a benzene ring () with a carboxyl () substituent. The benzoyl group is often abbreviated "Bz" (not to be confused with "Bn," which is used for benzyl), thus benzoic acid is also denoted as BzOH, since the benzoyl group has the formula –. It is the simplest aromaticity, aromatic carboxylic acid. The name is derived from benzoin (resin), gum benzoin, which was for a long time its only source. Benzoic acid occurs naturally in many plants and serves as an intermediate in the biosynthesis of many secondary metabolites. salt (chemistry), Salts of benzoic acid are used as food preservatives. Benzoic acid is an important Precursor (chemistry), precursor for the industrial synthesis of many other organic substances. The salts and esters of benzoic acid are known as benzoates (). History Benzoic acid was discovered in the sixteenth century. The dry dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfluorinated Compounds
A perfluorinated compound (PFC) or perfluoro compound is an organofluorine compound that lacks C-H bonds. Many perfluorinated compounds have properties that are quite different from their C-H containing analogues. Common functional groups in PFCs are OH, CO2H, chlorine, O, and SO3H. Electrofluorination is the predominant method for PFC production. Due to their chemical stability, some of these perfluorinated compounds bioaccumulate. Applications One class of perfluorinated compounds, the fluorosurfactants, are widely used in the production of teflon (PTFE) and related fluorinated polymers. They also have been used to confer hydrophobicity and stain-resistance to fabrics. They are components of fire-fighting foam. Fluorosurfactants (PFAS) reduce surface tension by concentrating at the liquid-air interface due to the ''lipo''phobicity of polyfluorocarbons. Chlorofluorocarbons are also perfluorinated compounds, many of which were formerly used as refrigerants (Freon) until they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
