• isomer
  • Kekulé used evidence that had accumulated in the intervening years-namely, that there always appeared to be only one isomer of any monoderivative of benzene, and that there always appeared to be exactly three isomers of every disubstituted derivative-now understood to correspond to the ortho, meta, and para patterns of arene substitution-to argue in support of his proposed structure. (wikipedia.org)
  • Diacetoxyiodo
  • Diacetoxyiodo)benzene, also known as phenyliodine(III) diacetate (PIDA) is a hypervalent iodine chemical reagent with formula C 6H 5I(OCOCH 3) 2. (wikipedia.org)
  • The compound can be prepared by reaction of iodobenzene with a mixture of trifluoroperacetic acid and trifluoroacetic acid in a method analogous to the synthesis of (diacetoxyiodo)benzene: It can also be prepared by dissolving diacetoxyiodobenzene (a commercially-available compound) with heating in trifluoroacetic acid: It also brings around the conversion of a hydrazone to a diazo compound, for example in the diazo-thioketone coupling. (wikipedia.org)
  • aromatic compounds
  • The new understanding of benzene, and hence of all aromatic compounds, proved to be so important for both pure and applied chemistry that in 1890 the German Chemical Society organized an elaborate appreciation in Kekulé's honor, celebrating the twenty-fifth anniversary of his first benzene paper. (wikipedia.org)
  • In the section Aromatischen Verbindungen (aromatic compounds), p. 315-347, Claus presents Kekulé's hypothetical structure for benzene (p. 317), presents objections to it, presents an alternative geometry (p. 320), and concludes that his alternative is correct (p. 326). (wikipedia.org)
  • benzoic acid
  • The benzene forms from decarboxylation of the preservative benzoic acid in the presence of ascorbic acid (vitamin C) and metal ions (iron and copper) that act as catalysts, especially under heat and light. (wikipedia.org)
  • The major cause of benzene in soft drinks is the decarboxylation of benzoic acid in the presence of ascorbic acid (vitamin C, E300) or erythorbic acid (a diastereomer of ascorbic acid, E315). (wikipedia.org)
  • Citric acid is not thought to induce significant benzene production in combination with benzoic acid, but some evidence suggests that in the presence of ascorbic or erythorbic acid and benzoic acid, citric acid may accelerate the production of benzene. (wikipedia.org)
  • In 1993, research showed how benzene can form from benzoic acid in the presence of vitamin C. In the summer of 1998, a number of well known soft drinks manufacturers had to withdraw large quantities of their products from sale after benzene contamination in some production plants was discovered. (wikipedia.org)
  • isomers
  • In fact, Dewar merely wrote the structure as one of seven possible isomers and believed that his experiments on benzene supported the (correct) structure that had been proposed by Kekulé. (wikipedia.org)
  • The three possible Dewar structures were considered as minor resonance contributors in the overall description of benzene, alongside other classic structures such as the isomers prismane, benzvalene and Claus' benzene. (wikipedia.org)
  • organic
  • Bis(trifluoroacetoxy)iodo)benzene, C 6H 5I(OCOCF 3) 2, is a hypervalent iodine compound used as a reagent in organic chemistry. (wikipedia.org)
  • Many people in the area of Price Landfill own residential wells, which were found to be contaminated with volatile organic compounds, including benzene & chloroform, and arsenic in 1980. (wikipedia.org)
  • Valence
  • After the development of valence bond theory in 1928, benzene was described primarily using its two major resonance contributors, the two Kekulé structures. (wikipedia.org)
  • hydrogen
  • Michael Faraday first isolated and identified benzene in 1825 from the oily residue derived from the production of illuminating gas, giving it the name bicarburet of hydrogen. (wikipedia.org)
  • The empirical formula for benzene was long known, but its highly polyunsaturated structure, with just one hydrogen atom for each carbon atom, was challenging to determine. (wikipedia.org)
  • citation needed] The proposed mechanism begins with hydrogen abstraction by the hydroxyl radical, which itself is produced by the Cu2+-catalysed reduction of dioxygen by ascorbic acid: Other factors that affect the formation of benzene are heat and light. (wikipedia.org)
  • aluminium
  • Hexamethyl Dewar benzene has been prepared by bicyclotrimerization of dimethylacetylene with aluminium chloride. (wikipedia.org)
  • It was first prepared by Hafner and Fischer by the reaction of CrCl3, aluminium, and benzene, in the presence of AlCl3. (wikipedia.org)
  • compound
  • from benzene.Benzene is an aromatic compound. (wikipedia.org)
  • The compound has nevertheless considerable strain energy and reverts to benzene with a chemical half-life of two days. (wikipedia.org)
  • The resulting organolithium compound can then be used as a nucleophile in various reactions, for example, with trimethylsilyl chloride: (Benzene)tricarbonylchromium is a useful catalyst for the hydrogenation of 1,3-dienes. (wikipedia.org)
  • chemical
  • Gradually, the sense developed among chemists that a number of substances were chemically related to benzene, comprising a diverse chemical family. (wikipedia.org)
  • Curiously, a similar, humorous depiction of benzene had appeared in 1886 in a pamphlet entitled Berichte der Durstigen Chemischen Gesellschaft (Journal of the Thirsty Chemical Society), a parody of the Berichte der Deutschen Chemischen Gesellschaft, only the parody had monkeys seizing each other in a circle, rather than snakes as in Kekulé's anecdote. (wikipedia.org)
  • This page provides supplementary chemical data on benzene. (wikipedia.org)
  • In February 2006, an unnamed former chemist at the FDA publicly revealed that benzene may be created as part of a chemical reaction during production of soft drinks, particularly those having an orange flavor. (wikipedia.org)
  • found
  • Benzene has been found in at least 1,000 of the 1,684 current or former NPL sites. (cdc.gov)
  • Although the total number of NPL sites evaluated for this substance is not known, the possibility exists that the number of sites at which benzene is found may increase in the future as more sites are evaluated. (cdc.gov)
  • Benzene is found in air, water, and soil. (cdc.gov)
  • Since Jan. 24, when the city last released detailed test results, the city has found 58 additional instances of benzene in the drinking water in Fountaingrove. (pressdemocrat.com)
  • Taking the worst example found to date of a soft drink containing 87.9 ppb benzene, someone drinking a 350 ml (12 oz) can would ingest 31 μg (micrograms) of benzene, almost equivalent to the benzene inhaled by a motorist refilling a fuel tank for three minutes. (wikipedia.org)
  • Air: A European study found that people breathe in 220 μg of benzene every day due to general atmospheric pollution. (wikipedia.org)
  • In 1990, a study reported having found benzene in bottles of Perrier for sale in the United States, resulting in a voluntary product recall. (wikipedia.org)
  • levels
  • The effect of dose, dose rate, route of administration, and species on tissue and blood levels of benzene metabolites. (nih.gov)
  • The city has now detected elevated levels of benzene in 145 samples taken from the water system in Fountaingrove. (pressdemocrat.com)
  • The first batch contained four test results showing benzene levels over 500 parts per billion, one of which was as high as 918 parts per billion. (pressdemocrat.com)
  • Benzene levels are regulated in drinking water nationally and internationally, and in bottled water in the United States, but only informally in soft drinks. (wikipedia.org)
  • In November 2005, the FDA received test results conducted by private citizens that benzene was forming at low levels in several types of beverages. (wikipedia.org)
  • known
  • This map displays locations where Benzene is known to be present. (cdc.gov)
  • The word "benzene" derives from "gum benzoin" (benzoin resin), an aromatic resin known to European pharmacists and perfumers since the 15th century as a product of southeast Asia. (wikipedia.org)
  • water
  • Benzene evaporates into air very quickly and dissolves slightly in water. (cdc.gov)
  • Most people can begin to taste benzene in water at 0.5�4.5 ppm. (cdc.gov)
  • Benzene can pass into air from water and soil surfaces. (cdc.gov)
  • Benzene in water and soil breaks down more slowly. (cdc.gov)
  • Benzene is slightly soluble in water and can pass through the soil into underground water. (cdc.gov)
  • A high pressure liquid chromatographic method for the separation and quantitation of water-soluble radiolabeled benzene metabolites. (nih.gov)
  • The maximum contaminant level (or MCL) for benzene in drinking water in the state is 1 part per billion. (pressdemocrat.com)
  • Various authorities have set limits on benzene content in drinking water. (wikipedia.org)
  • include
  • Natural sources of benzene, which include gas emissions from volcanoes and forest fires, also contribute to the presence of benzene in the environment. (cdc.gov)
  • Notes
  • World Health Organization (WHO): 10 ppb (WHO notes that benzene should be avoided whenever technically feasible. (wikipedia.org)
  • public health
  • This Public Health Statement is the summary chapter from the Toxicological Profile for Benzene . (cdc.gov)
  • Republic of Korea (South Korea): 10 ppb Canada: 5 ppb United States: 5 ppb European Union: 1 ppb State limits within the United States: California, Connecticut, New Jersey, and Florida: 1 ppb The EPA and California have set public health goals for benzene of 0 ppb and 0.15 ppb. (wikipedia.org)
  • formation
  • Storing soft drinks in warm conditions speeds up the formation of benzene. (wikipedia.org)
  • The International Council of Beverages Associations (ICBA) has produced advice to prevent or minimize benzene formation. (wikipedia.org)
  • In the early 1990s, the soft drink industry initially approached FDA with concerns about benzene formation in soft drinks. (wikipedia.org)
  • workers
  • There was a recent large spill of Benzene at the plant there, and the managers have threatened workers not to talk about what happened, not even to the occupational health clinic. (great-lakes.net)
  • Workers are fearful of the effects of Benzene and afraid of losing their jobs. (great-lakes.net)
  • health
  • I will be traveling to Sarnia to meet at an occupational health clinic for a presentation on Benzene. (great-lakes.net)
  • While there are alternatives to using sodium benzoate as a preservative, the casual consumption of such a drink is unlikely to pose a significant health hazard to a particular individual (see, for example, the EPA IRIS document on benzene). (wikipedia.org)
  • production
  • Because of its wide use, benzene ranks in the top 20 in production volume for chemicals produced in the United States. (cdc.gov)
  • Calcium disodium EDTA and sugars have been shown to inhibit benzene production in soft drinks. (wikipedia.org)
  • various
  • Various industries use benzene to make other chemicals, such as styrene (for Styrofoam� and other plastics), cumene (for various resins), and cyclohexane (for nylon and synthetic fibers). (cdc.gov)
  • parts
  • Most people can begin to smell benzene in air at approximately 60 parts of benzene per million parts of air (ppm) and recognize it as benzene at 100 ppm. (cdc.gov)
  • days
  • Once in the air, benzene reacts with other chemicals and breaks down within a few days. (cdc.gov)