|
Hexachloroethane
Hexachloroethane (perchloroethane) is an organochlorine compound with the chemical formula . Its structure is . It is a white or colorless solid at room temperature with a camphor-like odor. It has been used by the military in smoke compositions, such as base-eject smoke munitions ( smoke grenades). Hexachloroethane was discovered along with carbon tetrachloride by Michael Faraday in 1820. Faraday obtained it by chlorinating ethylene. Manufacture Chlorination of tetrachloroethylene at 100–140 °C with the presence of iron(III) chloride is the most commonly used commercial production method, however several other methods exist. A high purity form can be produced in a small scale by reacting chlorine together with barium carbide. In September 1997, it was reported as no longer being produced in the United States for commercial distribution, but was produced as a by-product of industrial chlorination process. : Applications Hexachloroethane has been used in the formulation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexabromoethane
Hexabromoethane (HBE, perbromoethane) is a perbromocarbon with the chemical formula . Its structure is . It is a yellowish white crystalline solid. It decomposes to tetrabromoethylene upon heating. Like many other halocarbons, HBE decomposes when exposed to radiation.Iyer, RM; Willard, JE, (1967) ''Production and Annealing of Br2 in the Radiolysis of Polycrystalline C2Br6: An In Situ Determination'', The Journal of Chemical Physics. 46 (9): 3501–3506. See also * Hexafluoroethane * Hexachloroethane * Bromoethane Bromoethane, also known as ethyl bromide, is a chemical compound of the haloalkanes group. It is abbreviated by chemists as EtBr (which is also used as an abbreviation for ethidium bromide). This volatile compound has an ether-like odor. Prepara ... * Pentabromoethane References Bromoalkanes {{chem-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrachloroethylene
Tetrachloroethylene, also known as perchloroethylene or under the systematic name tetrachloroethene, and abbreviations such as perc (or PERC), and PCE, is a chlorocarbon with the formula . It is a non-flammable, stable, colorless and heavy liquid widely used for dry cleaning of fabrics and occasionally as a highly effective automotive brake cleaner. It has a mildly sweet, sharp odor, detectable by most people at a concentration of 50 ppm. Tetrachloroethylene is regarded as a toxic substance, a human health hazard, and an environmental hazard. In 2020, the United States Environmental Protection Agency stated that "tetrachloroethylene exposure may harm the nervous system, liver, kidneys, and reproductive system, and may be harmful to unborn children", and reported that numerous toxicology agencies regard it as a carcinogen. History and production French chemist Henri Victor Regnault first synthesized tetrachloroethylene in 1839 by thermal decomposition of hexachloroethane f ... [...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] |
Tetrachloroethylene
Tetrachloroethylene, also known as perchloroethylene or under the systematic name tetrachloroethene, and abbreviations such as perc (or PERC), and PCE, is a chlorocarbon with the formula . It is a non-flammable, stable, colorless and heavy liquid widely used for dry cleaning of fabrics and occasionally as a highly effective automotive brake cleaner. It has a mildly sweet, sharp odor, detectable by most people at a concentration of 50 ppm. Tetrachloroethylene is regarded as a toxic substance, a human health hazard, and an environmental hazard. In 2020, the United States Environmental Protection Agency stated that "tetrachloroethylene exposure may harm the nervous system, liver, kidneys, and reproductive system, and may be harmful to unborn children", and reported that numerous toxicology agencies regard it as a carcinogen. History and production French chemist Henri Victor Regnault first synthesized tetrachloroethylene in 1839 by thermal decomposition of hexachloroethane f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octachloropropane
Octachloropropane or perchloropropane is the chemical compound with elemental formula and structural formula . Its molecule has a simple chain of three carbon atoms connected by single bonds, with chlorine atoms filling their remaining bonds. It is a chlorocarbon, specifically the third simplest perchloroalkane (after carbon tetrachloride and hexachloroethane). It can be described as a derivative of propane , with all hydrogen atoms replaced by chlorine. Octachloropropane is a clear white crystalline solid at room temperature, with hexagonal crystal structure. It is easily deformed by mechanical stress, without losing its crystal structure, like a metal. History Synthesis and characterization of octachloropropane was reported in 1875 by Krafft and Merz. Its remarkable crystal growth and deformation properties were noted by McCrone in 1949. Its use as a model for crystal deformation of minerals was pioneered by Win D. Means, Marc W. Jessel and others in the 1980s. Production O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Tetrachloride
Carbon tetrachloride, also known by many other names (such as carbon tet for short and tetrachloromethane, also IUPAC nomenclature of inorganic chemistry, recognised by the IUPAC), is a chemical compound with the chemical formula CCl4. It is a non-flammable, dense, colourless liquid with a "sweet" chloroform-like odour that can be detected at low levels. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, an anthelmintic and a cleaning agent, but has since been phased out because of environmental and safety concerns. Exposure to high concentrations of carbon tetrachloride can affect the central nervous system and degenerate the liver and kidneys. Prolonged exposure can be fatal. Properties In the carbon tetrachloride molecule, four chlorine atoms are positioned symmetrically as corners in a tetrahedron, tetrahedral configuration joined to a central carbon atom by single covalent bonds. Because of this symmetric geometry, CCl4 is non-polar. methane, ... [...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] |
Carbon Tetrachloride
Carbon tetrachloride, also known by many other names (such as carbon tet for short and tetrachloromethane, also IUPAC nomenclature of inorganic chemistry, recognised by the IUPAC), is a chemical compound with the chemical formula CCl4. It is a non-flammable, dense, colourless liquid with a "sweet" chloroform-like odour that can be detected at low levels. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, an anthelmintic and a cleaning agent, but has since been phased out because of environmental and safety concerns. Exposure to high concentrations of carbon tetrachloride can affect the central nervous system and degenerate the liver and kidneys. Prolonged exposure can be fatal. Properties In the carbon tetrachloride molecule, four chlorine atoms are positioned symmetrically as corners in a tetrahedron, tetrahedral configuration joined to a central carbon atom by single covalent bonds. Because of this symmetric geometry, CCl4 is non-polar. methane, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chain Transfer Agent
In polymer chemistry, chain transfer is a polymerization reaction by which the activity of a growing polymer chain is transferred to another molecule: \ce^\bullet + \ce^\bullet where • is the active center, P is the initial polymer chain, X is the end group, and R is the substituent to which the active center is transferred. Chain transfer reactions reduce the average molecular weight of the final polymer. Chain transfer can be either introduced deliberately into a polymerization (by use of a ''chain transfer agent'') or it may be an unavoidable side-reaction with various components of the polymerization. Chain transfer reactions occur in most forms of addition polymerization including radical polymerization, ring-opening polymerization, coordination polymerization, and cationic polymerization, as well as anionic polymerization. Types Chain transfer reactions are usually categorized by the nature of the molecule that reacts with the growing chain. * Transfer to chain tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barium Carbide
Barium carbide (also referred to as barium ethynediide or barium acetylide) is a chemical compound in the carbide family having the chemical formula . It consists of barium cations and acetylide anions . Preparation Barium carbide can be synthesized as an impure compound by reducing barium carbonate powder with metallic magnesium in the presence of carbon. Barium carbide can also be made by reducing carbon dioxide with hot barium metal at 600°C. These methods are used because of their high yield, and because the carbide is used to make acetylene. It can also be prepared by heating a barium amalgam and carbon powder mixture in a hydrogen current. The pure compound is prepared by reducing barium oxide with carbon at high temperature. Properties Barium carbide reacts similarly to calcium carbide, but it's more fusible. When exposed to extreme heat, the barium will evaporate leaving behind crystals of graphite. It can also absorb the carbon in a solution at high temperature. Hazard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lubricants
A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces. The property of reducing friction is known as lubricity. In addition to industrial applications, lubricants are used for many other purposes. Other uses include cooking ( oils and fats in use in frying pans and baking to prevent food sticking), to reduce rusting and friction in machinery, through the use of motor oil and grease, bioapplications on humans (e.g., lubricants for artificial joints), ultrasound examination, medical examination, and sexual intercourse. It is mainly used to reduce friction and to contribute to a better, more efficient functioning of a mechanism. History Lubricants have been in some use for thousands of years. Calcium soaps have been ide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcinogen
A carcinogen () is any agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and biologic agents such as viruses and bacteria. Most carcinogens act by creating mutations in DNA that disrupt a cell's normal processes for regulating growth, leading to uncontrolled cellular proliferation. This occurs when the cell's DNA repair processes fail to identify DNA damage allowing the defect to be passed down to daughter cells. The damage accumulates over time. This is typically a multi-step process during which the regulatory mechanisms within the cell are gradually dismantled allowing for unchecked cellular division. The specific mechanisms for carcinogenic activity is unique to each agent and cell type. Carcinogens can be broadly categorized, however, as activation-dependent and activation-independent which relate to the agent's ability to engage dir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
