with the development of data collections included in Thus, a double bond would exist with one neighbor during the first interval and with the other neighbor during the next interval. See, The word "benzoin" is derived from the Arabic expression ", Laurent, Auguste (1836) "Sur la chlorophénise et les acides chlorophénisique et chlorophénèsique,". Further loss of hydrogen gives "fused" aromatic hydrocarbons, such as naphthalene, anthracene, phenanthrene, and pyrene. Myeloperoxidase mutations result in loss of function and may result in decreased generation of toxic metabolites. Therefore, between the carbon atoms of benzene there were no fixed (i.e., constant) and distinct single or double bonds; instead, the bonds between the carbon atoms were identical. produce an m/z drop of 28 somewhere in the spectrum. However, NIST makes no warranties to that effect, and NIST Copyright © 1980, 1981-2020 John Wiley & Sons, Inc. All Rights Reserved. OSHA has also established an action level of 0.5 ppm to encourage even lower exposures in the workplace.[77]. and Informatics, NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data), NIST Mass Spectrometry Data Center, William E. Wallace, director, Modified by NIST for use in this application. Enter the desired X axis range Today, most benzene comes from the petrochemical industry, with only a small fraction being produced from coal.[46]. Technology, Office of Data The most common reactions of benzene involve substitution of a proton by other groups. Enter the desired X axis range Data from NIST Standard Reference Database 69: The National Institute of Standards and Technology (NIST) Data compilation copyright Chlorination is achieved with chlorine to give chlorobenzene in the presence of a Lewis acid catalyst such as aluminium tri-chloride. All mass spectra in this site (plus many more) are As a consequence, gasoline often contained several percent benzene before the 1950s, when tetraethyl lead replaced it as the most widely used antiknock additive. Hydrogenation cannot be stopped to give cyclohexene or cyclohexadienes as these are superior substrates. Database and to verify that the data contained therein have Table of Common Fragment Ions m/z Ions m/z Ions 15 CH3 63 C5H3 a 16 O 65 C5H5 a 17 OH 67 C5H7 18 H2O 69 C5H9 19 F 70 C5H10 26 CN 71 C5H11, C3H7-C=O 27 C2H3 72 C2H5-CO-CH2+H b 28 C2H4, … spectrum (can be printed in landscape orientation). [80] The NIOSH short-term exposure limit (STEL – 15 min) is 1 ppm. Benzene causes cancer in animals including humans. The American Petroleum Institute (API) stated in 1948 that "it is generally considered that the only absolutely safe concentration for benzene is zero". [17] In 1836, the French chemist Auguste Laurent named the substance "phène";[18] this word has become the root of the English word "phenol", which is hydroxylated benzene, and "phenyl", the radical formed by abstraction of a hydrogen atom (free radical H•) from benzene. [34] This vision, he said, came to him after years of studying the nature of carbon-carbon bonds. (2007). Please see the following for information about [76] These legal limits were based on studies demonstrating compelling evidence of health risk to workers exposed to benzene. Although benzene and pyridine are structurally related, benzene cannot be converted into pyridine. (This estimate assumes no threshold for benzene's carcinogenic effects.) For other uses, see, Except where otherwise noted, data are given for materials in their, Biological oxidation and carcinogenic activity, Critics pointed out a problem with Kekulé's original (1865) structure for benzene: Whenever benzene underwent substitution at the ortho position, two distinguishable isomers should have resulted, depending on whether a double bond or a single bond existed between the carbon atoms to which the substituents were attached; however, no such isomers were observed. Copyright © 2020 John Wiley & Sons, Inc. All Rights Reserved. The current ACGIH biological exposure limits for occupational exposure are 500 μg/g creatinine for muconic acid and 25 μg/g creatinine for phenylmercapturic acid in an end-of-shift urine specimen.[81][82][83][84]. With the global phaseout of leaded gasoline, benzene has made a comeback as a gasoline additive in some nations. Exact Mass: 162.140851 g/mol: Computed by PubChem 2.1 (PubChem release 2019.06.18) Monoisotopic Mass: 162.140851 g/mol: Computed by PubChem 2.1 (PubChem release 2019.06.18) Topological Polar Surface Area: 0 Ų: Computed by Cactvs (PubChem release 2019.06.18) Heavy Atom Count: 12: Computed by PubChem: Formal Charge: 0: Computed by PubChem: Complexity: 90.2 Using electrophilic aromatic substitution, many functional groups are introduced onto the benzene framework. Studies have shown that genotype at these loci may influence susceptibility to the toxic effects of benzene exposure. In some systems, even the benzene-to-xylenes ratio is modified to favor xylenes. Benzene is hepatically metabolized and excreted in the urine. Compound with free spectra: 315 NMR, 10 FTIR, 2 Raman, 2 Near IR, and 27 MS, On the intermediacy of phenyl hydrogen sulfates in the sulfonation of phenols. [65][85], Genetic polymorphisms in these enzymes may induce loss of function or gain of function. In 1865, the German chemist Friedrich August Kekulé published a paper in French (for he was then teaching in Francophone Belgium) suggesting that the structure contained a ring of six carbon atoms with alternating single and double bonds. Birch reduction, a non catalytic process, however selectively hydrogenates benzene to the diene. Copyright © 2020 by John Wiley & Sons, Inc., or related companies. Follow the links above to find out more about the data its accompanying search program. The exact placement of these absorptions can indicate the pattern of substitution on a benzene ring. In the bone marrow, MPO converts these polyphenols to benzoquinones. View the article PDF and any associated supplements and figures for a period of 48 hours. A small-area case-crossover study", "Advances in understanding benzene health effects and susceptibility", American Petroleum Institute, API Toxicological Review, Benzene, September 1948, "Advances in Understanding Benzene Health Effects and Susceptibility", International Agency for Research on Cancer, IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Overall Evaluations of Carcinogenicity: An Updating of IARC Monographs, "Benzene-induced cancers: abridged history and occupational health impact", "The toxicity of benzene and its metabolism and molecular pathology in human risk assessment", Occupational Safety and Health Standards, Toxic and Hazardous Substances, 1910.1028, Public Health Statement for Benzene, Agency for Toxic Substances and Disease Registry. To accurately reflect the nature of the bonding, benzene is often depicted with a circle inside a hexagonal arrangement of carbon atoms. In 1845, Charles Mansfield, working under August Wilhelm von Hofmann, isolated benzene from coal tar. on behalf of the United States of America. Select a region with no data or All rights reserved. The molecule is planar. Important examples include the sandwich and half-sandwich complexes, respectively, Cr(C6H6)2 and [RuCl2(C6H6)]2. It is used primarily as a precursor to the manufacture of chemicals with more complex structure, such as ethylbenzene and cumene, of which billions of kilograms are produced annually. The position of the carbonyl group influences the fragmentation pattern because the molecular ion fragments either side of the carbonyl group +the more stable the acylium ion RCO , the more abundant it will be and the more abundant the species the taller its peak in the mass spectrum the library and and you may need to create a new Wiley Online Library account. GSH mutations or deletions result in loss of function and result in decreased detoxification.

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