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Hexafluoroacetone
Hexafluoroacetone (HFA) is a chemical compound with the formula (CF3)2CO. It is structurally similar to acetone; however, its reactivity is markedly different. It a colourless, hygroscopic, nonflammable, highly reactive gas characterized by a musty odour. The most common form of this substance is hexafluoroacetone sesquihydrate (1.5 H2O), which is a hemihydrate of hexafluoropropane-2,2-diol , a geminal diol. Synthesis The industrial route to HFA involves treatment of hexachloroacetone with HF: :(CCl3)2CO + 6 HF → (CF3)2CO + 6 HCl Hexafluoropropylene oxide rearranges to give HFA. In the laboratory, HFA can be prepared in a two step process from perfluoropropene. In the first step KF catalyzes the reaction of the alkene with elemental sulfur to give the 1,3-dithietane CF3)2CSsub>2. This species is then oxidized by iodate to give (CF3)2CO. Uses Hexafluoroacetone is used in the production of hexafluoroisopropanol: :(CF3)2CO + H2 → (CF3)2CHOH It is also used as a pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexafluoroacetone Imine
Hexafluoroacetone (HFA) is a chemical compound with the formula (CF3)2CO. It is structurally similar to acetone; however, its reactivity is markedly different. It a colourless, hygroscopic, nonflammable, highly reactive gas characterized by a musty odour. The most common form of this substance is hexafluoroacetone sesquihydrate (1.5 H2O), which is a hemihydrate of hexafluoropropane-2,2-diol , a geminal diol. Synthesis The industrial route to HFA involves treatment of hexachloroacetone with HF: :(CCl3)2CO + 6 HF → (CF3)2CO + 6 HCl Hexafluoropropylene oxide rearranges to give HFA. In the laboratory, HFA can be prepared in a two step process from perfluoropropene. In the first step KF catalyzes the reaction of the alkene with elemental sulfur to give the 1,3-dithietane CF3)2CSsub>2. This species is then oxidized by iodate to give (CF3)2CO. Uses Hexafluoroacetone is used in the production of hexafluoroisopropanol: :(CF3)2CO + H2 → (CF3)2CHOH It is also used as a precur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemiaminal
In organic chemistry, a hemiaminal (also carbinolamine) is a functional group or type of chemical compound that has a hydroxyl group and an amine attached to the same carbon atom: . R can be hydrogen or an alkyl group. Hemiaminals are intermediates in imine formation from an amine and a carbonyl by alkylimino-de-oxo-bisubstitution. Hemiaminals can be viewed as a blend of aminals and geminal diol. They are a special case of amino alcohols. Classification according to amine precursor Addition of ammonia The adducts formed by the addition of ammonia to aldehydes have long been studied. Compounds containing both a primary amino group and a hydroxyl group bonded to the same carbon atom are rare. They are invoked but rarely observed as intermediates in the reaction of ammonia and aldehydes and ketones. One example of this rare functionality is the adduct of ammonia and hexafluoroacetone, . The C-substituted derivatives are obtained by reaction of aldehydes and ammonia: :3 RCHO ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexachloroacetone
Hexachloroacetone is an organic compound with the formula (Cl3C)2CO. It is also called hexachloropropanone or perchloroacetone. Numbers indicating the position of the chlorine-atoms are generally omitted as all the possible positions are substituted with chlorine. It is a colorless liquid, slightly soluble in water. Reactions and uses Hexachloroacetone functions equivalently to trichloroacetyl chloride, i.e. as an trichloroacetylating agent. The main use of hexachloroacetone is as a pesticide. For the use of hexachloroacetone in the preparation of a novel insect repellent see Perkow reaction. The industrial route to hexafluoroacetone involves treatment of hexachloroacetone with HF: :(CCl3)2CO + 6 HF → (CF3)2CO + 6 HCl See also * Chloroacetone Chloroacetone is a chemical compound with the formula . At STP it is a colourless liquid with a pungent odour. On exposure to light, it turns to a dark yellow-amber colour. It was used as a tear gas in World War I. Synthesis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexafluoro-2-propanol
Hexafluoroisopropanol, commonly abbreviated HFIP, is the organic compound with the formula (CF3)2CHOH. This fluoroalcohol finds use as solvent and synthetic intermediate. It appears as a colorless, volatile liquid that is characterized by a strong, pungent odor. As a solvent hexafluoro-2-propanol is polar and exhibits strong hydrogen bonding properties enabling it to dissolve substances that serve as hydrogen-bond acceptors, such as amides and ethers. (CF3)2CHOH is classified as a hard Lewis acid and its acceptor properties are discussed in the ECW model. Its relative acceptor strength toward a series of bases, versus other Lewis acids, can be illustrated by C-B plots. Dual XH–π interaction of HFIP with arenes has been found (benzene/HFIP, 7.22 kcal/mol) even stronger than the hydrogen bond in a water dimer (5-6 kcal/mol). Hexafluoro-2-propanol is transparent to UV light with high density, low viscosity and low refractive index. Production and uses Hexafluoro-propan-2-ol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imine
In organic chemistry, an imine ( or ) is a functional group or organic compound containing a carbon–nitrogen double bond (). The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bonds. Imines are common in synthetic and naturally occurring compounds and they participate in many reactions. Structure For ketimines and aldimines, respectively, the five core atoms (C2C=NX and C(H)C=NX, X = H or C) are coplanar. Planarity results from the sp2-hybridization of the mutually double-bonded carbon and the nitrogen atoms. The C=N distance is 1.29-1.31 Å for nonconjugated imines and 1.35 Å for conjugated imines. By contrast, C-N distances in amines and nitriles are 1.47 and 1.16 Å, respectively. Rotation about the C=N bond is slow. Using NMR spectroscopy, both E- and Z-isomers of aldimines have been detected. Owing to steric effects, the E isomer is favored. Nomenclature and classification The term "imine" was coin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexafluoroisobutylene
Hexafluoroisobutylene is an organofluorine compound with the formula (CF3)2C=CH2. This colorless gas is structurally similar to isobutylene. It is used as a comonomer in the production of modified polyvinylidene fluoride. It is produced in a multistep process starting with the reaction of acetic anhydride with hexafluoroacetone. It is oxidized by sodium hypochlorite to hexafluoroisobutylene oxide. As expected, it is a potent dienophile.{{cite journal, title=The chemistry and utility of hexafluoroisobutylene (HFIB) and hexafluoroisobutylene oxide (HFIBO), author= Murphy, Peter M., journal=Journal of Fluorine Chemistry, year=2013, volume=156, pages=345–362, doi=10.1016/j.jfluchem.2013.07.015 See also *Perfluoroisobutene Perfluoroisobutene (PFIB) is the perfluorocarbon counterpart of the hydrocarbon isobutene and has the formula (CF3)2C=CF2. An alkene, it is a colorless gas that is notable as a highly toxic perfluoroalkene. Few simple alkenes are as toxic. Safet ... Refere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexafluoro-2-propanol
Hexafluoroisopropanol, commonly abbreviated HFIP, is the organic compound with the formula (CF3)2CHOH. This fluoroalcohol finds use as solvent and synthetic intermediate. It appears as a colorless, volatile liquid that is characterized by a strong, pungent odor. As a solvent hexafluoro-2-propanol is polar and exhibits strong hydrogen bonding properties enabling it to dissolve substances that serve as hydrogen-bond acceptors, such as amides and ethers. (CF3)2CHOH is classified as a hard Lewis acid and its acceptor properties are discussed in the ECW model. Its relative acceptor strength toward a series of bases, versus other Lewis acids, can be illustrated by C-B plots. Dual XH–π interaction of HFIP with arenes has been found (benzene/HFIP, 7.22 kcal/mol) even stronger than the hydrogen bond in a water dimer (5-6 kcal/mol). Hexafluoro-2-propanol is transparent to UV light with high density, low viscosity and low refractive index. Production and uses Hexafluoro-propan-2-ol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4,4′-(Hexafluoroisopropylidene)diphthalic Anhydride
4,4′-(Hexafluoroisopropylidene)diphthalic anhydride (6FDA) is an aromatic organofluorine compound and the dianhydride of 4,4′-(hexafluoroisopropylidene)bisphthalic acid (name derived from phthalic acid). Synthesis The raw materials for 6FDA are hexafluoroacetone and orthoxylene. With hydrogen fluoride as a catalyst, the compounds react to 4,4′-(hexafluoroisopropylidene)bis(o-xylene). This is oxidized with potassium permanganate to 4,4′-(hexafluoroisopropylidene)bisphthalic acid. Dehydration gives the dianhydride 6FDA. Applications 6FDA is used as monomer for the synthesis of fluorinated polyimides. These are prepared by the polymerisation of 6FDA with an aromatic diamine such as 3,5-diaminobenzoic acid or 4,4'-diaminodiphenyl sulfide. Such fluorinated polyimides are used in special applications, e. g. used to make gas-permeable polymer membranes, "Gas transfer and blood compatibility of fluorinated polyimide membranes." '' Journal of Biomaterials Science, Polymer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexafluoropropylene Oxide
Hexafluoropropylene oxide (HFPO) is an intermediate used in industrial organofluorine chemistry; specifically it is a monomer for fluoropolymers. This colourless gas is the epoxide of hexafluoropropylene, that is fluorinated analog of propylene oxide, HFPO is produced by DuPont and 3M and as a precursor to the lubricant Krytox and related materials. It is generated by oxidation of perfluoropropylene, e.g. with oxygen as well as other oxidants. Reactivity Fluoride catalyzes the formation of the perfluorinated polyethers such as Krytox. The initial step entails nucleophilic attack at the middle carbon to give the perfluoropropoxide anion, which in turn attacks another monomer. This process generates a polymer terminated by an acyl fluoride, which is hydrolyzed to the carboxylic acid which is decarboxylated with fluorine. The net polymerization reaction can be represented as: :n+2 CF3CFCF2O → CF3CF2CF2O(CF(CF3)CF2O)nCF2CF3 + CO Upon heating above 150 °C, HFPO decompos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ketone
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 reta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrophile
In chemistry, an electrophile is a chemical species that forms bonds with nucleophiles by accepting an electron pair. Because electrophiles accept electrons, they are Lewis acids. Most electrophiles are positively charged, have an atom that carries a partial positive charge, or have an atom that does not have an octet of electrons. Electrophiles mainly interact with nucleophiles through addition and substitution reactions. Frequently seen electrophiles in organic syntheses include cations such as H+ and NO+, polarized neutral molecules such as HCl, alkyl halides, acyl halides, and carbonyl compounds, polarizable neutral molecules such as Cl2 and Br2, oxidizing agents such as organic peracids, chemical species that do not satisfy the octet rule such as carbenes and radicals, and some Lewis acids such as BH3 and DIBAL. Organic chemistry Addition of halogens These occur between alkenes and electrophiles, often halogens as in halogen addition reactions. Comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equilibrium Constant
The equilibrium constant of a chemical reaction is the value of its reaction quotient at chemical equilibrium, a state approached by a dynamic chemical system after sufficient time has elapsed at which its composition has no measurable tendency towards further change. For a given set of reaction conditions, the equilibrium constant is independent of the initial analytical concentrations of the reactant and product species in the mixture. Thus, given the initial composition of a system, known equilibrium constant values can be used to determine the composition of the system at equilibrium. However, reaction parameters like temperature, solvent, and ionic strength may all influence the value of the equilibrium constant. A knowledge of equilibrium constants is essential for the understanding of many chemical systems, as well as biochemical processes such as oxygen transport by hemoglobin in blood and acid–base homeostasis in the human body. Stability constants, formation con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
