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Benzene ring Benzene is a planar molecule; six carbon atoms and six hydrogen atoms are arranged in a ring, with double bonds between the carbon atoms. Their positions are generated by subroutines which can generate rings with an arbitrary number of atoms, but six is the chemically most significant value. Figure: Another representation of a benzene molecule in which smaller spheres are used to represent the nuclei and lines representing bonds have been inserted. delta.cs.cinvestav.mx /~mcintosh/comun/geom/node51.html   (153 words)

Benzene ring - Benzenering Benzene is an aromatic hydrocarbon, and the second [n]-annulene ([6]-annulene). In the 19th and early 20th centuries, benzene was used as an aftershave because of its pleasant smell. The reaction is the acylation of an aromatic ring (such as benzene) with an acyl chloride using a strong Lewis acid catalyst. www.kopete.org /Benzene-ring.html   (0 words)

plastics.com Insert anchor ring for chain and plug (screws into center of mandrel). One will normally see what looks like concentric rings typical of twin screw extruders known affectionately as "Anger Rings". www.plastics.com /articlelive   (0 words)

[No title] The six-membered ring in benzene is a perfect hexagon (all carbon-carbon bonds have an identical length of 1.40 Å). The six benzene rings in coronene are fused in a planar ring; whereas the six rings in hexahelicene are not joined in a larger ring, but assume a helical turn, due to the crowding together of the terminal ring atoms. Benzene and 1,3,5,7-cyclooctatetraene are examples of annulenes; they are named [6]annulene and [8]annulene respectively, according to a general nomenclature system in which the number of pi-electrons in an annulene is designated by a number in brackets. www.cem.msu.edu /~reusch/VirtualText/react3.htm   (4132 words)

Firehouse.Com HazMat Zone - The Street Chemist - The "Street Chemist" Part-6 Benzene is represented by the characteristic "benzene ring". Toluene is composed of a benzene ring with a methyl radical attached. Unlike benzene, toluene, and xylene, styrene is reactive, but not because of the benzene ring, rather the vinyl radical attached to the benzene ring. www.firehouse.com /training/hazmat/chemist/2002/3_chemist.html   (1199 words)

Structure of Benzene Benzene does not react with bromine unless a very bright light or a strong catalyst is used, and then the reaction is not an addition reaction. When resonance theory was first applied to understanding the structure of benzene, the key feature seemed to be a resonance hybrid of ring structures containing alternating single and double bonds. Even though the outcome of the attack of electrophiles on benzene is substitution rather than addition, the first step is the same as in electrophilic addition to alkenes -- attack of the electrophile on a pi bond and the formation of a new sigma bond between a carbon atom and the electrophile. chemistry2.csudh.edu /rpendarvis/BenzStr.html   (1570 words)

Benzene Summary Benzene's hexagonal ring structure is of considerable importance because it is the basis for most of the class of chemicals known as aromatic compounds. Benzene is no longer used as an additive in gasoline but it is an important industrial solvent and precursor in the production of drugs, plastics, synthetic rubber, and dyes. Benzene occurs sufficiently often as a component of organic molecules that there is a Unicode symbol with the code 232C to represent it: ⌬. www.bookrags.com /Benzene   (3351 words)

St. Louis Benzene Lawyers – Missouri Dangerous Drug Litigation Attorneys, Toxic Exposure, Cancer Benzene, also known as benzol, is a clear, sweet-smelling, highly flammable liquid chemical used mainly in making rubber, plastics, dyes, paints, rubber, resins, detergents, lubricants, drugs, pesticides, nylon and synthetic fibers. Benzene can be found in small amounts almost everywhere – in the outdoor air, in the home and in the workplace. Workers exposed to high levels of benzene are at the greatest risk of suffering its long-term harmful effects: acute myelogenous leukemia, acute lymphocytic leukemia, anemia and other forms of cancer and leukemia. www.brownandcrouppen.com /benzene.html   (564 words)

MOLECULAR ORBITAL TREATMENT OF BENZENE-BOND LINGTH ANALYSIS IN BENZENE--MODERN REPRESENTATION-stability of benzene ring A: In benzene ring pi-molecular orbital is in a state of vibration due to this vibration resonance is produced. Hence, pi-electrons of benzene are not readily available at particular positions as in alkenes, and so do not assist the attack of a weak electrophile in the same way as in alkenes. On the other hand the reactivity of benzene ring is also affected by the presence of annular pi-electronic cloud which acts as a repelling shield to any nucleophile attack. www.citycollegiate.com /benzene4.htm   (527 words)

FR-2.1 A hydrocarbon parent component that consists of four or more ortho-fused benzene rings in a straight linear arrangement is named from the numerical prefix (ref 10) denoting the number of benzene rings followed by the ending '-acene' (derived from anthracene). A hydrocarbon parent component that consists of a monocyclic hydrocarbon with an even number of carbon atoms and benzene rings ortho-fused to alternate sides is named from the numerical prefix (ref 10) denoting the number of benzene rings followed by the ending '-phenylene'. A hydrocarbon parent component of six or more rings that consists of a benzene ring fused to the 3,4- position of phenanthrene and further benzene rings fused in a similar way is named from the numerical prefix (ref 10) denoting the total number of rings followed by the ending '- helicene'. www.chem.qmul.ac.uk /iupac/fusedring/FR21.html   (830 words)

Ring Molecule Geometry Cyclohexane, a ring of 6 carbons with all single bonds, is not a flat ring either. The benzene ring consists of six carbon atoms bonded in a flat or planar hexagon ring. The p orbitals are perpendicular to the plane of the ring. www.elmhurst.edu /~chm/vchembook/209rings.html   (474 words)

Aromatics The current definition of aromatic compounds includes only those with a benzene ring, which is a special six carbon ring compound with three alternating double bonds. The bonds between the carbons in benzene are neither pure single bonds nor pure double bonds, but rather a some hybrid of the two. If other groups are attached to the benzene ring, they are named according to group names followed by the word benzene. www.elmhurst.edu /~chm/vchembook/505aromatics.html   (414 words)

Untitled Document Benzene and all other substances whose structures resemble benzene and have similiar chemical properties are classified as aromatic hydrocarbons. When the benzene ring has two substituted groups attached to it, three isomeric forms of the compound are possible. When three or more substituent groups are on a benzene ring, the carbon atoms in the ring may be numbered clockwise or counterclockwise starting with one of the substituted groups. www.dmacc.edu /instructors/rbwollaston/aromatic_rings2.htm   (319 words)

Benzene Data Sheet Benzene is a clear, colourless liquid, that is highly flammable with a low boiling point and high vapour pressure. Total emissions of benzene into the atmosphere are expected to decline in the future, primarily because of the planned reduction of emissions of volatile organic compounds from light-duty vehicles and the efforts to reduce volatile organic compound emissions from a variety of other sources in order to control ground-level ozone (Government of Canada, 1993). In the bacterial degradation of benzene, the aromatic hydrocarbons are oxidized to catechol (orthodihydroxybenzene) or its derivatives by a dioxygenase and a dehydrogenase. wvlc.uwaterloo.ca /biology447/modules/intro/assignments/crossley.htm   (2374 words)

Biodegradation of Aromatic Hydrocarbons Because it is cyclic and unsaturated, benzene is structurally similar to the cyclic alkenes. Because all of the important aromatic hydrocarbons that occur in petroleum are derivatives of benzene, a reaction that is common to all pathways that lead to mineralization of aromatic substrates is cleavage of the benzene ring. Ring cleavage can occur by either of two pathways: the ortho-cleavage pathway, in which the aromatic ring is split between the two carbon atoms bearing hydroxyl groups, or the meta-cleavage pathway, in which the ring is broken between a hydroxylated carbon atom and an adjacent unsubstituted carbon atom (Gottschalk, 1986). www.ence.umd.edu /~eseagren/bioAHC97.htm   (1299 words)

Hartley & O'Brien: Benzene FAQ Benzene has been widely accepted as a leukemogen since the 1940's, based largely on case reports associating pancytopenia with subsequent development of leukemia, as well as biological plausibility. Benzene can also be measured in the blood, however, since benzene disappears rapidly from the blood, measurements are accurate only for recent exposures. Benzene causes harmful effects on the bone marrow and can cause a decrease in red blood cells leading to anemia, aplastic anemia, myelofibrosis, and myelodysplastic syndrome. www.toxictortlawyers.com /html/library/benzene_faq.htm   (1576 words)

ESA Science & Technology: ISO detects benzene in space They think benzene is produced by stars at a specific stage of evolution, and that it is an essential chemical step towards the synthesis of more complex organic molecules whose true nature is still unclear -although their fingerprints are very conspicuous in the Universe. Benzene is made of six atoms of carbon chained together to form a ring, plus six atoms of hydrogen, one per carbon. The authors think that there could be a few molecules of benzene per cubic centimetre, a value considered to be high, although the estimated density of molecules of all kinds in the area observed is ten million per cubic centimetre. sci.esa.int /science-e/www/object/index.cfm?fobjectid=25880   (809 words)

Highbeam Encyclopedia - Search Results for benzene It boils at 80.1°C and solidifies at 5.5°C. Benzene is a hydrocarbon, with formula C 6 H 6. The simplest picture of the benzene molecule, proposed by the German chemist Friedrich Kekulé (1865), is a hexagon of six carbon atoms... A benzene molecule is a hexagonal ring of six unsaturated carbon atoms (benzene ring). www.encyclopedia.com /SearchResults.aspx?Q=benzene   (844 words)

The Benzene Ring But in practise, it was found that 3 di-substituted benzenes could exist, but when methods were devised for assigning structures to them only one was shown to be 1,2-isomer. Despite these criticisms, the hexagonal structure of benzene, which Kekule had proposed solved many problems the chemists of the time faced and so it was widely accepted. Below are several other attempts that were made to explain the equivalence of all six positions in the benzene ring with the concept of the tetravalent carbon atom. www.jergym.hiedu.cz /~canovm/mechanic/pravidl2/lad/r.htm   (612 words)

StainsFile - Benzene structure Benzene is the parent compound of all aromatic compounds. The current explanation for benzene's structure is that the bonds between the carbon atoms of benzene are all the same. The delocalised electrons in this aryl ring is the fundamental cause of the absorbance of light in these organic compounds, and consequently the appearance of colour in dyes. stainsfile.info /StainsFile/theory/science/benzring.htm   (761 words)

Columbia Encyclopedia- benzene - AOL Research & Learn It boils at 80.1°C and solidifies at 5.5°C. Benzene is a hydrocarbon, with formula C6H6. The simplest picture of the benzene molecule, proposed by the German chemist Friedrich Kekulé (1865), is a hexagon of six carbon atoms joined by alternating single and double bonds and each bearing one hydrogen atom, symbolized by ⌬. It is the first of a series of hydrocarbons known as the benzene series, formed by the substitution of methyl groups, CH3, for the hydrogen atoms of the benzene molecule. reference.aol.com /columbia/_a/benzene/20051205193609990010   (241 words)

benzene The 12 atoms of benzene are planar with carbon in the sp2 hybrid state and 120° bond angles. If benzene were to undergo addition,resonance would be disrupted and this would render the structure less stable. Why does benzene possess 6 bonds intermediate between C=C and C-C? According to resonance, the bonds are not C-C or C=C but a hybrid of the two. mooni.fccj.org /~ethall/benzene/benzene.htm   (887 words)

Cook County Illinois Benzene Lawyer :: Benzene :: North Chicago Illinois Toxic Litigation Attorney Chicago Lawyer Benzene is one of the most widely produced chemicals in the United States. Benzene is also a known human carcinogen, as determined by the Department of Health and Human Services. If you have been injured by benzene exposure, you may be entitled to workers' compensation benefits in addition to a personal injury claim. www.pintas.com /attorney-lawyer-1008876.html   (284 words)

bonding in benzene - sp2 hybridisation and delocalisation The difference in benzene is that each carbon atom is joined to two other similar carbon atoms instead of just one. Benzene is a regular hexagon because all the bonds are identical. If you added other atoms to a benzene ring you would have to use some of the delocalised electrons to join the new atoms to the ring. www.chemguide.co.uk /basicorg/bonding/benzene2.html   (877 words)

Naming Organic Compounds - Aromatics The term "aromatic" came to be because earlier compounds found with the rings had pleasant fragrances, but it turns out that the ring has nothing to do with smell. At last, a structural model was proposed and accepted as the benzene ring. If a benzene ring is considered a branch(in larger molecules), then the benzene ring is called a phenyl group. www.angelfire.com /bc2/OrgChem/aromatics.html   (205 words)

No. 265: Inventing Benzene He identified her distinctive ring, which turned up in the servant's possession. The lady's odd ring also lingered in Kekule's mind -- it had carried the old alchemy seal of two intertwined serpents biting each other's tail. As he nodded, he dreamt of the twining serpents on that old ring, whirling in the flames. www.uh.edu /engines/epi265.htm   (471 words)

CHEMystery: Organic Chemistry: Aromatic Hydrocarbons The aromatic hydrocarbons include benzene and the alkyl derivatives of benzene, a six sided ring drawn with alternating single and double bonds or with a circle in the middle. Since the benzene ring looks very much like a triene (alkene with three double bonds), it should be expected that its properties would be like one, but it is not. Benzene will react by substitution with chlorine, bromine, and nitric acid, provided that a Lewis acid catalyst is present. library.advanced.org /3659/orgchem/aromatic.html   (206 words)

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