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Difluoroacetylene
Difluoroacetylene is a compound of carbon and fluorine having molecular formula . A linear molecule, its two carbons are joined by a triple bond and have terminal fluorines: . The molecule is the perfluorocarbon analog of acetylene, . Preparation of difluoroacetylene is difficult, with danger of explosions and with low yields. Nevertheless, the compound has been made, isolated, and characterized by various spectroscopical methods (MS, NMR, Photoelectron- and IR spectroscopy). The compound is of interest as a precursor to fluoropolymers containing double bonds, analogous to polyacetylene Polyacetylene (IUPAC name: polyethyne) usually refers to an organic polymer with the repeating unit . The name refers to its conceptual construction from polymerization of acetylene to give a chain with repeating olefin groups. This compound is .... Difluoroacetylene is stable in the gaseous phase under low pressure. At liquid nitrogen temperature, it is slowly changing to tetrafluorobutatriene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichloroacetylene
Dichloroacetylene (DCA) is an organochlorine compound with the formula . It is a colorless, explosive liquid that has a sweet and "disagreeable" odor. Production Dichloroacetylene was first synthesized from trichloroethylene by E. Ott, W. Ottemeyer and K. Packendorff in 1930. Ether solutions of dichloroacetylene are relatively stable, and such solutions can be safely generated by the dehydrochlorination of trichlorethylene. A popular procedure uses potassium hydride as the base: : A trace of methanol is required. It has also been generated (and used in situ) using lithium diisopropylamide under anhydrous conditions as well as potassium hydroxide. Dichloroacetylene can occur and be stable in air at concentrations of up to 200 parts per million if certain other compounds, such as ether, with which it forms an azeotrope (boiling point of 32 °C), and trichloroethylene, are also present. Adventitious routes It is a by-product in the production of vinylidene chloride. For instance, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dibromoacetylene
Dibromoacetylene is an organic compound with the chemical formula . It is a molecular chemical compound containing acetylene, with its hydrogen substituted by bromine. Its molecule is linear, with the structure . Production Dibromoacetylene can be made by reacting 1,1,2-tribromoethylene with potassium hydroxide. This method has a danger of causing explosions. Another way is to react acetylene with phenyl lithium (at −50 °C) to make lithium acetylide, which then reacts with bromine to yield the product. Yet another way is to react acetylene with sodium hypobromite NaOBr. Properties Dibromoacetylene is explosive and sensitive to air. Its appearance is a clear water like liquid. It has a sweetish smell, but makes a white fume in air that then smells like ozone, possibly because it forms ozone. Dibromoacetylene is lachrymatory. Dibromoacetylene can be polymerised to polydibromoacetylene using catalysts like titanium tetrachloride and triethylaluminium. Polydibromoacetylen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diiodoacetylene
Diiodoacetylene is the organoiodine compound with the formula . It is a white, volatile solid that dissolves in organic solvents. It is prepared by iodination of trimethylsilylacetylene. Although samples explode above 80 °C, diiodoacetylene is the most readily handled of the dihaloacetylenes. Dichloroacetylene, for example, is more volatile and more explosive. As confirmed by X-ray crystallography, diiodoacetylene is linear, with the structure . It is however a shock, heat and friction sensitive compound. Like other haloalkynes, diiodoacetylene is a strong halogen bond In chemistry, a halogen bond (XB or HaB) occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecul ... donor.{{cite journal , last1 = Cavallo , first1 = G. , last2 = Metrangolo , first2 = P. , last3 = Milani , first3 = R. , last4 = Pilati , first4 = T. , l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexafluoroethane
Hexafluoroethane is an organofluorine compound with the chemical formula . It is a non-flammable colorless odorless gas negligibly soluble in water and slightly soluble in methanol. Its structure is . It is an extremely potent and long-lived greenhouse gas. It is the perfluorocarbon counterpart to the hydrocarbon ethane. Physical properties Hexafluoroethane's Phase (matter), solid phase has two Polymorphism (materials science), polymorphs. In the scientific literature, different phase transition temperatures have been stated. The latest works assign it at 103 K (−170 °C). Below 103 K it has a slightly disordered structure, and over the transition point, it has a Cubic crystal system, body centered cubic structure. The critical point is at 19.89 °C (293.04 K) and 30.39 Bar (unit), bar. Table of densities: Vapor density is 4.823 (air = 1), Relative density, specific gravity at 21 °C is 4.773 (air = 1) and specific volume at 21 °C is 0.1748 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Union Of Pure And Applied Chemistry
The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is a member of the International Science Council (ISC). IUPAC is registered in Zürich, Switzerland, and the administrative office, known as the "IUPAC Secretariat", is in Research Triangle Park, North Carolina, United States. IUPAC's executive director heads this administrative office, currently Greta Heydenrych. IUPAC was established in 1919 as the successor of the International Congress of Applied Chemistry for the advancement of chemistry. Its members, the National Adhering Organizations, can be national chemistry societies, national academies of sciences, or other bodies representing chemists. There are fifty-four National Adhering Organizations and three Associate National Adhering Organizations. IUPAC's Inter-divisional Committee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylene
Acetylene (Chemical nomenclature, systematic name: ethyne) is a chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pure form and thus is usually handled as a solution. Pure acetylene is odorless, but commercial grades usually have a marked odor due to impurities such as divinyl sulfide and phosphine.Compressed Gas Association (1995Material Safety and Data Sheet – Acetylene As an alkyne, acetylene is Saturated and unsaturated compounds, unsaturated because its two carbon atoms are Chemical bond, bonded together in a triple bond. The carbon–carbon triple bond places all four atoms in the same straight line, with CCH bond angles of 180°. The triple bond in acetylene results in a high energy content that is released when acetylene is burned. Discovery Acetylene was discovered in 1836 by Edmund Davy, who identified it as a "new carburet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyacetylene
Polyacetylene (IUPAC name: polyethyne) usually refers to an organic polymer with the repeating unit . The name refers to its conceptual construction from polymerization of acetylene to give a chain with repeating olefin groups. This compound is conceptually important, as the discovery of polyacetylene and its high Ionic conductivity (solid state), conductivity upon doping (semiconductor), doping helped to launch the field of organic conductive polymers. The high electrical conductivity discovered by Hideki Shirakawa, Alan Heeger, and Alan MacDiarmid for this polymer led to intense interest in the use of organic compounds in microelectronics (organic semiconductors). This discovery was recognized by the Nobel Prize in Chemistry in 2000. Early work in the field of polyacetylene research was aimed at using doped polymers as easily processable and lightweight "plastic metals". Despite the promise of this polymer in the field of conductive polymers, many of its properties such as insta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluoropolymers
A fluoropolymer is a fluorocarbon-based polymer with multiple carbon–fluorine bonds. It is characterized by a high resistance to solvents, acids, and Base (chemistry), bases. The best known fluoropolymer is polytetrafluoroethylene under the brand name "Teflon," trademarked by the DuPont, DuPont Company. History In 1938, polytetrafluoroethylene (DuPont brand name Teflon) was discovered by accident by a recently hired DuPont Ph.D., Roy J. Plunkett. While working with tetrafluoroethylene gas to develop refrigerants, he noticed that a previously pressurized cylinder had no pressure remaining. In dissecting the cylinder, he found a mass of white solid in a quantity similar to that of the tetrafluoroethylene gas. It was determined that this material was a new-to-the-world polymer. Tests showed the substance was resistant to corrosion from most acids, bases and solvents and had better high temperature stability than any other plastic. By early 1941, a crash program was making substa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared Spectroscopy
Infrared spectroscopy (IR spectroscopy or vibrational spectroscopy) is the measurement of the interaction of infrared radiation with matter by absorption, emission, or reflection. It is used to study and identify chemical substances or functional groups in solid, liquid, or gaseous forms. It can be used to characterize new materials or identify and verify known and unknown samples. The method or technique of infrared spectroscopy is conducted with an instrument called an infrared spectrometer (or spectrophotometer) which produces an infrared spectrum. An IR spectrum can be visualized in a graph of infrared light absorbance (or transmittance) on the vertical axis vs. frequency, wavenumber or wavelength on the horizontal axis. Typical units of wavenumber used in IR spectra are reciprocal centimeters, with the symbol cm−1. Units of IR wavelength are commonly given in micrometers (formerly called "microns"), symbol μm, which are related to the wavenumber in a reciprocal way ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Magnetic Resonance
Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are disturbed by a weak oscillating magnetic field (in the near field) and respond by producing an electromagnetic signal with a frequency characteristic of the magnetic field at the nucleus. This process occurs near resonance, when the oscillation frequency matches the intrinsic frequency of the nuclei, which depends on the strength of the static magnetic field, the chemical environment, and the magnetic properties of the isotope involved; in practical applications with static magnetic fields up to ca. 20 tesla, the frequency is similar to VHF and UHF television broadcasts (60–1000 MHz). NMR results from specific magnetic properties of certain atomic nuclei. High-resolution nuclear magnetic resonance spectroscopy is widely used to determine the structure of organic molecules in solution and study molecular physics and crystals as well as non-crysta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosion
An explosion is a rapid expansion in volume of a given amount of matter associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Explosions may also be generated by a slower expansion that would normally not be forceful, but is not allowed to expand, so that when whatever is containing the expansion is broken by the pressure that builds as the matter inside tries to expand, the matter expands forcefully. An example of this is a Volcano, volcanic eruption created by the expansion of magma in a magma chamber as it rises to the surface. Supersonic explosions created by high explosives are known as detonations and travel through shock waves. wikt:subsonic, Subsonic explosions are created by low explosives through a slower combustion process known as deflagration. Causes For an explosion to occur, there must be a rapid, forceful expansion of matter. There are numerous ways this can happen, both natura ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon
Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 electrons. It belongs to group 14 of the periodic table. Carbon makes up about 0.025 percent of Earth's crust. Three Isotopes of carbon, isotopes occur naturally, carbon-12, C and carbon-13, C being stable, while carbon-14, C is a radionuclide, decaying with a half-life of 5,700 years. Carbon is one of the timeline of chemical element discoveries#Pre-modern and early modern discoveries, few elements known since antiquity. Carbon is the 15th abundance of elements in Earth's crust, most abundant element in the Earth's crust, and the abundance of the chemical elements, fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. Carbon's abundance, its unique diversity of organic compounds, and its unusual abi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
