It is highly flammable and is present abundantly in nature. NQ01 and GSH shift metabolism away from toxicity. [94] About 50% of the entire nationwide (United States) exposure to benzene results from smoking tobacco or from exposure to tobacco smoke. Next, the diol is newly reduced by NADH to catechol. [44] In 1870, the German chemist Viktor Meyer first applied Gräbe's nomenclature to benzene.[45]. The High Stability of Benzene In the absence of the catalyst, benzene is impervious to hydrogen. Each carbon atom has a hydrogen attached to it. Benzene. 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. Examples of simple benzene derivatives are phenol, toluene, and aniline, abbreviated PhOH, PhMe, and PhNH2, respectively. It is said to be highly toxic in nature and is also known as a carcinogen; which exposure to this may lead to leukemia. One way of understanding the carcinogenic effects of benzene is by examining the products of biological oxidation. Toluene is also processed into benzene.[61]. Benzene | C6H6 | CID 241 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety/hazards/toxicity information, supplier lists, and more. 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. "VIII. 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. Replacing one CH with N gives the compound pyridine, C5H5N. In the body, benzene is enzymatically converted to a series of oxidation products including muconic acid, phenylmercapturic acid, phenol, catechol, hydroquinone and 1,2,4-trihydroxybenzene. 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. In his 1890 paper, Armstrong represented benzene nuclei within polycyclic benzenoids by placing inside the benzene nuclei a letter "C", an abbreviation of the word "centric". All the carbons have … The carbon atoms are represented by a corner that is bonded to other atoms. Manufacture of some of these benzene-containing formulations ceased in about 1950, although Liquid Wrench continued to contain significant amounts of benzene until the late 1970s. In catalytic reforming, a mixture of hydrocarbons with boiling points between 60–200 °C is blended with hydrogen gas and then exposed to a bifunctional platinum chloride or rhenium chloride catalyst at 500–525 °C and pressures ranging from 8–50 atm. Structure of the Benzene Molecule. [66][67][68] The specific hematologic malignancies that benzene is associated with include: acute myeloid leukemia (AML), aplastic anemia, myelodysplastic syndrome (MDS), acute lymphoblastic leukemia (ALL), and chronic myeloid leukemia (CML).[69]. Interest since its discovery Kekulé was the first to suggest a sensible structure for benzene a. 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