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Nitroaromatic Compound
In organic chemistry, nitro compounds are organic compounds that contain one or more nitro functional groups (). The nitro group is one of the most common explosophores (functional group that makes a compound explosive) used globally. The nitro group is also strongly electron-withdrawing. Because of this property, bonds alpha (adjacent) to the nitro group can be acidic. For similar reasons, the presence of nitro groups in aromatic compounds retards electrophilic aromatic substitution but facilitates nucleophilic aromatic substitution. Nitro groups are rarely found in nature. They are almost invariably produced by nitration reactions starting with nitric acid. Synthesis Preparation of aromatic nitro compounds Aromatic nitro compounds are typically synthesized by nitration. Nitration is achieved using a mixture of nitric acid and sulfuric acid, which produce the nitronium ion (), which is the electrophile: + The nitration product produced on the lar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trinitrophenol
Picric acid is an organic compound with the formula (O2N)3C6H2OH. Its IUPAC name is 2,4,6-trinitrophenol (TNP). The name "picric" comes from el, πικρός (''pikros''), meaning "bitter", due to its bitter taste. It is one of the most acidic phenols. Like other strongly nitrated organic compounds, picric acid is an explosive, which is its primary use. It has also been used as medicine (antiseptic, burn treatments) and as a dye. History Picric acid was probably first mentioned in the alchemical writings of Johann Rudolf Glauber. Initially, it was made by nitrating substances such as animal horn, silk, indigo, and natural resin, the synthesis from indigo first being performed by Peter Woulfe during 1771. The German chemist Justus von Liebig had named picric acid (rendered in French as ). Picric acid was given that name by the French chemist Jean-Baptiste Dumas in 1841. Its synthesis from phenol, and the correct determination of its formula, were accomplished during 1841. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleophilic Substitution
In chemistry, a nucleophilic substitution is a class of chemical reactions in which an electron-rich chemical species (known as a nucleophile) replaces a functional group within another electron-deficient molecule (known as the electrophile). The molecule that contains the electrophile and the leaving functional group is called the substrate. The most general form of the reaction may be given as the following: :\text\mathbf + \ce + \text\mathbf The electron pair (:) from the nucleophile (Nuc) attacks the substrate () and bonds with it. Simultaneously, the leaving group (LG) departs with an electron pair. The principal product in this case is . The nucleophile may be electrically neutral or negatively charged, whereas the substrate is typically neutral or positively charged. An example of nucleophilic substitution is the hydrolysis of an alkyl bromide, R-Br under basic conditions, where the attacking nucleophile is hydroxyl () and the leaving group is bromide (). :R-Br + OH- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmosphere (unit)
The standard atmosphere (symbol: atm) is a unit of pressure defined as Pa. It is sometimes used as a ''reference pressure'' or ''standard pressure''. It is approximately equal to Earth's average atmospheric pressure at sea level. History The standard atmosphere was originally defined as the pressure exerted by 760 mm of mercury at and standard gravity (''g''n = ). It was used as a reference condition for physical and chemical properties, and was implicit in the definition of the Celsius temperature scale, which defined as the boiling point of water at this pressure. In 1954, the 10th General Conference on Weights and Measures (CGPM) adopted ''standard atmosphere'' for general use and affirmed its definition of being precisely equal to dynes per square centimetre (). This defined both temperature and pressure independent of the properties of particular substance. In addition, the CGPM noted that there had been some misapprehension that it "led some physicists to believe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propane
Propane () is a three-carbon alkane with the molecular formula . It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel in domestic and industrial applications and in low-emissions public transportation. Discovered in 1857 by the French chemist Marcellin Berthelot, it became commercially available in the US by 1911. Propane is one of a group of liquefied petroleum gases (LP gases). The others include butane, propylene, butadiene, butylene, isobutylene, and mixtures thereof. Propane has lower volumetric energy density, but higher gravimetric energy density and burns more cleanly than gasoline and coal. Propane gas has become a popular choice for barbecues and portable stoves because its low −42 °C boiling point makes it vaporise inside pressurised liquid containers (2 phases). Propane powers buses, forklifts, taxis, outboard boat motors, and ic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-Nitropropane
2-Nitropropane (2-NP) is a solvent. It is a colorless liquid and is classified as a nitro compound. Preparation 2-Nitropropane is produced by the high-temperature vapor-phase nitration of propane, usually with impurities of 1-nitropropane. 2-Nitropropane is also produced as a volatile by-product that can be captured during Leonard's ring-closure hydantoin preparation. Uses 2-Nitropropane is used as a solvent or additive in inks, paints, adhesives, varnishes, polymers, resins, fuel, and coatings. It is also used as a feedstock for other industrial chemicals, and also in the synthesis of pharmaceuticals such as phentermine, chlorphentermine, and teclozan. It serves as an oxidant in the Hass–Bender oxidation process. Safety 2-Nitropropane is a constituent of tobacco smoke Tobacco smoke is a sooty aerosol produced by the incomplete combustion of tobacco during the tobacco smoking, smoking of cigarettes and other tobacco products. Temperatures in burning cigarettes range from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1-Nitropropane
1-Nitropropane (1-NP) is a solvent. It is a colorless liquid, an isomer of 2-nitropropane (2-NP), and classified as a nitro compound. Preparation 1-nitropropane is produced industrially by the reaction of propane and nitric acid. This reaction forms four nitroalkanes: nitromethane, nitroethane, 1-nitropropane, and 2-nitropropane. 1-nitropropane is also a byproduct of the process for making 2-nitropropane, which is done by vapour phase nitration of propane. Uses Most 1-nitropropane is used as a starting material for other compounds. The other uses are solvent-based paints, solvent-based inks and adhesives, and as a solvent for chemical reactions. Safety 1-nitropropane is toxic to humans and can cause damage to the kidneys and liver. The vapours are irritating for the lungs and eyes and the maximum exposure rate is 25 ppm. It is not known to be a carcinogen. Reactions 1-nitropropane decomposes under the influence of heat into toxic gases. It also reacts violently with oxidizin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitroethane
Nitroethane is an organic compound having the chemical formula C2H5NO2. Similar in many regards to nitromethane, nitroethane is an oily liquid at standard temperature and pressure. Pure nitroethane is colorless and has a fruity odor. Preparation Nitroethane is produced industrially by treating propane with nitric acid at 350–450 °C. This exothermic reaction produces four industrially significant nitroalkanes: nitromethane, nitroethane, 1-nitropropane, and 2-nitropropane. The reaction involves free radicals, such as CH3CH2CH2O., which arise via homolysis of the corresponding nitrite ester. These alkoxy radicals are susceptible to C—C fragmentation reactions, which explains the formation of a mixture of products.Sheldon B. Markofsky “Nitro Compounds, Aliphatic” in ''Ullmann's Encyclopedia of Industrial Chemistry'', Wiley-VCH, Weinheim, 2002. . Alternatively, nitroethane can be produced by the Victor Meyer reaction of haloethanes such as chloroethane, bromo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitromethane
Nitromethane, sometimes shortened to simply "nitro", is an organic compound with the chemical formula . It is the simplest organic nitro compound. It is a polar liquid commonly used as a solvent in a variety of industrial applications such as in extractions, as a reaction medium, and as a cleaning solvent. As an intermediate in organic synthesis, it is used widely in the manufacture of pesticides, explosives, fibers, and coatings. Nitromethane is used as a fuel additive in various motorsports and hobbies, e.g. Top Fuel drag racing and miniature internal combustion engines in radio control, control line and free flight model aircraft. Preparation Nitromethane is produced industrially by combining propane and nitric acid in the gas phase at 350–450 °C (662–842 °F). This exothermic reaction produces the four industrially significant nitroalkanes: nitromethane, nitroethane, 1-nitropropane, and 2-nitropropane. The reaction involves free radicals, including t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkane
In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carbon–carbon bonds are single. Alkanes have the general chemical formula . The alkanes range in complexity from the simplest case of methane (), where ''n'' = 1 (sometimes called the parent molecule), to arbitrarily large and complex molecules, like pentacontane () or 6-ethyl-2-methyl-5-(1-methylethyl) octane, an isomer of tetradecane (). The International Union of Pure and Applied Chemistry (IUPAC) defines alkanes as "acyclic branched or unbranched hydrocarbons having the general formula , and therefore consisting entirely of hydrogen atoms and saturated carbon atoms". However, some sources use the term to denote ''any'' saturated hydrocarbon, including those that are either monocyclic (i.e. the cycloalkanes) or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitration
In organic chemistry, nitration is a general class of chemical processes for the introduction of a nitro group into an organic compound. The term also is applied incorrectly to the different process of forming nitrate esters between alcohols and nitric acid (as occurs in the synthesis of nitroglycerin). The difference between the resulting molecular structures of nitro compounds and nitrates is that the nitrogen atom in nitro compounds is directly bonded to a non-oxygen atom (typically carbon or another nitrogen atom), whereas in nitrate esters (also called organic nitrates), the nitrogen is bonded to an oxygen atom that in turn usually is bonded to a carbon atom (nitrito group). There are many major industrial applications of nitration in the strict sense; the most important by volume are for the production of nitroaromatic compounds such as nitrobenzene. Nitration reactions are notably used for the production of explosives, for example the conversion of guanidine to nitrog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Radical
A daughter category of ''Ageing'', this category deals only with the biological aspects of ageing. Ageing Ailments of unknown cause Biogerontology Biological processes Causes of death Cellular processes Gerontology Life extension Metabolic disorders Metabolism Old age Time in life Wikipedia categories named after diseases and disorders {{CatAutoTOC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
