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Pentaphenylphosphorane
Pentaphenylphosphorus is an organic phosphorane containing five phenyl groups connected to a central phosphorus atom. The phosphorus atom is considered to be in the +5 oxidation state. The chemical formula could be written as P(C6H5)5 or Ph5P, where Ph represents the phenyl group. It was discovered and reported in 1949 by Georg Wittig. Formation Pentaphenylphosphorus can be formed by the action of phenyllithium on tetraphenylphosphonium bromide or tetraphenylphosphonium iodide. Properties In the solid form of pure pentaphenylphosphorus, molecules have a trigonal bipyramid shape. The crystal structure of the pure form is monoclinic with a=10.03, b=17.22 c=14.17 Å and β=112.0°. The unit cell volume is 2267.5 Å3. There are four of the formula per unit cell (Z=4). Space group is ''Cc''. Pentaphenyl phosphorus can also crystallise with some of the solvent, (to form a solvate). With tetrahydrofuran, the crystal structure of which is triclinic, with space group ''P'', wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorane
A phosphorane (IUPAC name: λ5-phosphane) is a functional group in organophosphorus chemistry with pentavalent phosphorus. It has the general formula PR5. The parent hydride compound is the hypothetical molecule PH5. The derivative pentaphenylphosphorane (Ph5P) is stable. Phosphoranes adopt a trigonal bipyramidal molecular geometry with the two apical bonds longer than the three equatorial bonds. Hypervalent bonding is described by inclusion of non-bonding MOs, as also invoked for the closely related molecule phosphorus pentafluoride.G. L. Miessler and D. A. Tarr “Inorganic Chemistry” 3rd Ed, Pearson/Prentice Hall publisher, . Phosphoranes of the type R3P=CR2 are more common and more important. Phosphoranes are also considered to be one of the resonance structures of ylides, these compounds feature a tetrahedral phosphorus center including a phosphorus–carbon double bond. These compounds are used as reagents in the Wittig reaction The Wittig reaction or Wittig ole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclohexane
Cyclohexane is a cycloalkane with the molecular formula . Cyclohexane is non-polar. Cyclohexane is a colorless, flammable liquid with a distinctive detergent-like odor, reminiscent of cleaning products (in which it is sometimes used). Cyclohexane is mainly used for the industrial production of adipic acid and caprolactam, which are precursors to nylon. Cyclohexyl () is the alkyl substituent of cyclohexane and is abbreviated Cy. Production Modern On an industrial scale, cyclohexane is produced by hydrogenation of benzene in the presence of a Raney nickel catalyst. Producers of cyclohexane account for approximately 11.4% of global demand for benzene. The reaction is highly exothermic, with ΔH(500 K) = -216.37 kJ/mol. Dehydrogenation commenced noticeably above 300 °C, reflecting the favorable entropy for dehydrogenation. : Early Unlike benzene, cyclohexane is not found in natural resources such as coal. For this reason, early investigators synthesized their cyclohex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorus(V) Compounds
Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Earth. It has a concentration in the Earth's crust of about one gram per kilogram (compare copper at about 0.06 grams). In minerals, phosphorus generally occurs as phosphate. Elemental phosphorus was first isolated as white phosphorus in 1669. White phosphorus emits a faint glow when exposed to oxygen – hence the name, taken from Greek mythology, meaning 'light-bearer' (Latin ), referring to the " Morning Star", the planet Venus. The term ''phosphorescence'', meaning glow after illumination, derives from this property of phosphorus, although the word has since been used for a different physical process that produces a glow. The glow of phosphorus is caused by oxidation of the white (but not red) phosphorus — a process now called chemilum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromobenzene
Bromobenzene is an aryl halide, C6H5Br. It is a colourless liquid although older samples can appear yellow. It is a reagent in organic synthesis. Synthesis and reactions Bromobenzene is prepared by the action of bromine on benzene in the presence of Lewis acid catalysts such as aluminium chloride or ferric bromide. Bromobenzene is used to introduce a phenyl group into other compounds. One method involves its conversion to the Grignard reagent, phenylmagnesium bromide Phenylmagnesium bromide, with the simplified formula , is a magnesium-containing organometallic compound. It is commercially available as a solution in diethyl ether or tetrahydrofuran (THF). Phenylmagnesium bromide is a Grignard reagent. It is o .... This reagent can be used, e.g. in the reaction with carbon dioxide to prepare benzoic acid. Other methods involve palladium-catalyzed coupling reactions, such as the Suzuki reaction. Bromobenzene is used as a precursor in the manufacture of phencyclidi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorobenzene
Chlorobenzene is an aromatic organic compound with the chemical formula C6H5Cl. This colorless, flammable liquid is a common solvent and a widely used intermediate in the manufacture of other chemicals. Uses Historical The major use of chlorobenzene is as an intermediate in the production of herbicides, dyestuffs, and rubber. Chlorobenzene is also used as a high-boiling solvent in industrial applications as well as in the laboratory. Chlorobenzene is nitrated on a large scale to give a mixture of 2-nitrochlorobenzene and 4-nitrochlorobenzene, which are separated. These mononitrochlorobenzenes are converted to related 2-nitrophenol, 2-nitroanisole, bis(2-nitrophenyl)disulfide, and 2-nitroaniline by nucleophilic displacement of the chloride, with respectively sodium hydroxide, sodium methoxide, sodium disulfide, and ammonia. The conversions of the 4-nitro derivative are similar. Chlorobenzene once was used in the manufacture of pesticides, most notably DDT, by reaction w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorobenzene
Fluorobenzene is the chemical compound with the formula C6H5F, often abbreviated PhF. A colorless liquid, it is a precursor to many fluorophenyl compounds. Preparation PhF was first reported in 1886 by O. Wallach at the University of Bonn, who prepared the compound in two steps. Phenyldiazonium chloride was first converted to a triazene using piperidine: : hN2l + 2 (CH2)5NH → PhN=N-N(CH2)5 + CH2)5NH2l The triazine was then cleaved with hydrofluoric acid: :PhN=N-N(CH2)5 + 2 HF → PhF + N2 + CH2)5NH2 Historical note: in Wallach's era, the element fluorine was symbolized with "Fl". Thus, his procedure is subtitled "Fluorbenzol, C6H5Fl". On the laboratory scale, PhF is prepared by the thermal decomposition of the benzenediazonium tetrafluoroborate: :PhN2BF4 → PhF + BF3 + N2 According to the procedure, solid hN2F4 is heated with a flame to initiate an exothermic reaction, which also affords boron trifluoride and nitrogen gas. Product PhF and BF3 are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tributyltin Chloride
Tributyltin chloride is an organotin compound with the formula ( C4H9)3SnCl. It is a colorless liquid that is soluble in organic solvents. Preparation and reactions The compound is prepared by a redistribution reaction by combining stannic chloride and tetrabutyltin: :3 (C4H9)4Sn + SnCl4 → 4 (C4H9)3SnCl Tributyltin chloride hydrolyzes to the oxide C4H9)3Snsub>2O Tributyltin chloride is used as a precursor to other organotin compounds{{cite journal, title=Palladium-catalyzed Coupling Of Acid Chlorides With Organotin Reagents: Ethyl (E)-4-(4-nitrophenyl)-4-oxo-2-butenoate, authors=A. F. Renaldo, J. W. Labadie, And J. K. Stille, journal=Org. Synth., year=1989, volume=67, page=86, doi=10.15227/orgsyn.067.0086 and reagents, such as tributyltin hydride Tributyltin hydride is an organotin compound with the formula (C4H9)3SnH. It is a colorless liquid that is soluble in organic solvents. The compound is used as a source of hydrogen atoms in organic synthesis. Synthesis an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
