Search results
- Benzene is formed from both natural processes and human activities. Natural sources of benzene include volcanoes and forest fires. Benzene is also a natural part of crude oil, gasoline, and cigarette smoke.
emergency.cdc.gov/agent/benzene/basics/facts.asp
People also ask
Where is benzene found?
What is the odour of benzene?
Is benzene a hydrocarbon?
How is benzene made?
Is benzene a petrochemical?
Who discovered benzene?
Trace amounts of benzene are found in petroleum and coal. It is a byproduct of the incomplete combustion of many materials. For commercial use, until World War II, much of benzene was obtained as a by-product of coke production (or "coke-oven light oil") for the steel industry.
Benzene works by causing cells not to work correctly. For example, it can cause bone marrow not to produce enough red blood cells, which can lead to anemia. Also, it can damage the immune system by changing blood levels of antibodies and causing the loss of white blood cells.
- Overview
- Discovery of benzene
- Characteristics of benzene
- Uses of benzene
benzene (C6H6), simplest organic, aromatic hydrocarbon and parent compound of numerous important aromatic compounds. Benzene is a colourless liquid with a characteristic odour and is primarily used in the production of polystyrene. It is highly toxic and is a known carcinogen; exposure to it may cause leukemia. As a result, there are strict control...
Benzene was first discovered by the English scientist Michael Faraday in 1825 in illuminating gas. In 1834 German chemist Eilhardt Mitscherlich heated benzoic acid with lime and produced benzene. In 1845 German chemist A.W. von Hofmann isolated benzene from coal tar.
Britannica Quiz
So Much Chemistry, So Little Time Quiz
The structure of benzene has been of interest since its discovery. German chemists Joseph Loschmidt (in 1861) and August Kekule von Stradonitz (in 1866) independently proposed a cyclic arrangement of six carbons with alternating single and double bonds. Kekule subsequently modified his structural formula to one in which oscillation of the double bonds gave two equivalent structures in rapid equilibrium. In 1931 American chemist Linus Pauling suggested that benzene had a single structure, which was a resonance hybrid of the two Kekule structures.
Modern bonding models (valence-bond and molecular orbital theories) explain the structure and stability of benzene in terms of delocalization of six of its electrons, where delocalization in this case refers to the attraction of an electron by all six carbons of the ring instead of just one or two of them. This delocalization causes the electrons to be more strongly held, making benzene more stable and less reactive than expected for an unsaturated hydrocarbon. As a result, the hydrogenation of benzene occurs somewhat more slowly than the hydrogenation of alkenes (other organic compounds that contain carbon-carbon double bonds), and benzene is much more difficult to oxidize than alkenes. Most of the reactions of benzene belong to a class called electrophilic aromatic substitution that leave the ring itself intact but replace one of the attached hydrogens. These reactions are versatile and widely used to prepare derivatives of benzene.
Experimental studies, especially those employing X-ray diffraction, show benzene to have a planar structure with each carbon-carbon bond distance equal to 1.40 angstroms (Å). This value is exactly halfway between the C=C distance (1.34 Å) and C—C distance (1.46 Å) of a C=C—C=C unit, suggesting a bond type midway between a double bond and a single bond (all bond angles are 120°). Benzene has a boiling point of 80.1 °C (176.2 °F) and a melting point of 5.5 °C (41.9 °F), and it is freely soluble in organic solvents, but only slightly soluble in water.
At one time, benzene was obtained almost entirely from coal tar; however, since about 1950, these methods have been replaced by petroleum-based processes. More than half of the benzene produced each year is converted to ethylbenzene, then to styrene, and then to polystyrene. The next largest use of benzene is in the preparation of phenol. Other uses include the preparation of aniline (for dyes) and dodecylbenzene (for detergents).
Are you a student? Get Britannica Premium for only 24.95 - a 67% discount!
Oct 14, 2022 · Benzene is found in emissions from power plants, primarily those using coal and oil as fuels, as well as from car exhaust. EPA has set a maximum contaminant level (MCL) for benzene of 5 parts per billion in drinking water.
Oct 4, 2024 · Benzene: general information. Updated 4 October 2024. Overview. Benzene is a colourless, volatile liquid with a characteristic sweet odour. It is described as an ‘aromatic’ hydrocarbon; each...
- Benzene is a colourless, volatile liquid with a characteristic sweet odour. It is described as an ‘aromatic’ hydrocarbon; each molecule of benzene...
- Benzene is an important chemical; it is used a starting material for a wide range of chemicals which feed into major industrial manufacturing proce...
- Benzene will quickly evaporate when it is released into the environment. Major sources of benzene include vehicle exhaust, evaporation of petrol, p...
- Exposure to benzene is most likely to occur through inhalation. Benzene is a common air pollutant, present at higher levels in polluted areas (for...
- It is very unlikely that the general population will be exposed to a level of benzene high enough to cause adverse health effects. However, if you...
- HSE: Benzene and youHSE: Benzene in motor vehicle repairNHS.UK information on poisoningUKTIS: best use of medicines in pregnancy
Sep 5, 2019 · Benzene, a molecule with the chemical structure of C6H6,has a molar mass of just over 78 grams/mole. At room temperature, Benzene tends to exist in a liquid state. It is colorless and has a very ...
Benzene is a colourless liquid with a characteristic odour of formula C6H6. Benzene is a closed ring of six carbon atoms linked by bonds that alternate between single and double bonds. Each carbon atom is bound by a single hydrogen atom. Benzene melts at a temperature of 5.5 ° C, boils at 80.1°C.
