FACTOID # 9: The bookmobile capital of America is Kentucky.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
RELATED ARTICLES
People who viewed "Benzene" also viewed:
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Benzene
Benzene
Benzene
IUPAC name Benzene (or 1,3,5-cyclohexatriene)
Other names Benzol
Identifiers
CAS number [71-43-2]
PubChem 241
RTECS number CY1400000
SMILES c1ccccc1
C1=CC=CC=C1
Properties
Molecular formula C6H6
Molar mass 78.1121 g/mol
Appearance Colorless liquid
Density 0.8786 g/cm³, liquid
Melting point

5.5 °C (278.6 K) Chemical structure of benzene Selfmade by cacycle File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... PubChem is a database of chemical molecules. ... RTECS, also known as Registry of Toxic Effects of Chemical Substances, is a database of toxicity information compiled from the open scientific literature that is available for charge. ... The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII strings. ... A chemical formula is an easy way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... For other uses, see Density (disambiguation). ... The melting point of a solid is the temperature range at which it changes state from solid to liquid. ...

Boiling point

80.1 °C (353.2 K) Italic text This article is about the boiling point of liquids. ...

Solubility in water 0.8 g/L (25 °C)
Viscosity 0.652 cP at 20 °C
Dipole moment 0 D
Hazards
MSDS External MSDS
EU classification (F)
Carc. Cat. 1
Muta. Cat. 2
Toxic (T)
NFPA 704
4
3
0
 
R-phrases R45, R46, R11, R36/38,R48/23/24/25, R65
S-phrases S53, S45
Flash point −11 °C
Related compounds
Related compounds toluene
borazine
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Benzene, or Benzol (see also Benzine), is an organic chemical compound and a known carcinogen with the molecular formula C6H6. It is sometimes abbreviated Ph–H. Benzene is a colorless and highly flammable liquid with a sweet smell and a relatively high melting point. Because of this, its use as an additive in gasoline is now limited, but it is an important industrial solvent and precursor in the production of drugs, plastics, synthetic rubber, and dyes. Benzene is a natural constituent of crude oil, but it is usually synthesized from other compounds present in petroleum. Benzene is an aromatic hydrocarbon and the second [n]-annulene ([6]-annulene), a cyclic hydrocarbon with a continuous pi bond. Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... For other uses, see Viscosity (disambiguation). ... The poise (P; IPA: ) is the unit of dynamic viscosity in the centimetre gram second system of units. ... The Earths magnetic field, which is approximately a dipole. ... The debye (symbol: D) is a non-SI and non-CGS unit of electrical dipole moment. ... An example MSDS in a US format provides guidance for handling a hazardous substance and information on its composition and properties. ... It has been suggested that this article or section be merged into Benzene. ... Council Directive 67/548/EEC of 27 June 1967 on the approximation of laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances (as amended) is the main European Union law concerning chemical safety. ... Look up carcinogen in Wiktionary, the free dictionary. ... In biology, a mutagen (Latin, literally origin of change) is a physical or chemical agent that changes the genetic information (usually DNA) of an organism and thus increases the number of mutations above the natural background level. ... NFPA 704 is a standard maintained by the U.S. National Fire Protection Association. ... Image File history File links NFPA_704. ... R-phrases are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous substances and preparations. ... S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. ... For other uses, see Flash point (disambiguation). ... Toluene, also known as methylbenzene or phenylmethane is a clear, water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. ... Borazine is an inorganic compound composed of the elements boron, nitrogen and hydrogen. ... It has been suggested that this article or section be merged into Benzene. ... It has been suggested that this article or section be merged into Benzene. ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... The relative dielectric constant of a material under given conditions is a measure of the extent to which it concentrates electrostatic lines of flux. ... It has been suggested that this article or section be merged into Benzene. ... It has been suggested that this article or section be merged into Benzene. ... Ultraviolet-Visible Spectroscopy or Ultraviolet-Visible Spectrophotometry (UV/ VIS) involves the spectroscopy of photons (spectrophotometry). ... Infrared spectroscopy (IR spectroscopy) is the subset of spectroscopy that deals with the infrared region of the electromagnetic spectrum. ... Nuclear magnetic resonance spectroscopy most commonly known as NMR spectroscopy is the name given to the technique which exploits the magnetic properties of certain nuclei. ... Mass spectrometry (previously called mass spectroscopy (deprecated) or informally, mass-spec and MS) is an analytical technique that measures the mass-to-charge ratio of ions. ... The plimsoll symbol as used in shipping In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals exactly). ... Benzol can mean: Benzole Benzene Category: ... Benzine, also known as petroleum ether, is a group of various volatile, highly flammable, liquid hydrocarbon mixtures used chiefly as nonpolar solvents. ... Benzene is the simplest of the arenes, a family of organic compounds An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. ... Look up chemical compound in Wiktionary, the free dictionary. ... Look up carcinogen in Wiktionary, the free dictionary. ... For other uses, see Carbon (disambiguation). ... This article is about the chemistry of hydrogen. ... In chemistry, the phenyl group or phenyl ring (often abbreviated as -Ph) is the functional group with the formula -C6H5 Picture where the six carbon atoms are arranged in a cyclic manner. ... Color is an important part of the visual arts. ... Flammable or Flammability refers to the ease at which a substance will ignite, causing fire or combustion. ... Petrol redirects here. ... For other uses, see Solvent (disambiguation). ... This article does not cite any references or sources. ... For other uses, see Plastic (disambiguation). ... This does not cite any references or sources. ... Look up dye in Wiktionary, the free dictionary. ... Petro redirects here. ... An aromatic hydrocarbon (abbreviated as AH) or arene [1] is a hydrocarbon, the molecular structure of which incorporates one or more planar sets of six carbon atoms that are connected by delocalised electrons numbering the same as if they consisted of alternating single and double covalent bonds. ... Annulenes are completely conjugated monocyclic hydrocarbons. ... Electron atomic and molecular orbitals, showing a Pi-bond at the bottom right of the picture. ...

Contents

History

Discovery

The word "benzene" derives historically from "gum benzoin", sometimes called "benjamin" (i.e., benzoin resin), an aromatic resin known to European pharmacists and perfumers since the 15th century as a product of southeast Asia. "Benzoin" is itself a corruption of the Arabic expression "luban jawi," or "frankincense of Java." An acidic material was derived from benzoin by sublimation, and named "flowers of benzoin," or benzoic acid. The hydrocarbon derived from benzoic acid thus acquired the name benzin, benzol, or benzene.[1] Benzene has been the subject of many studies by scientists ranging from Michael Faraday to Linus Pauling. 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.[2][3] In 1833, Eilhard Mitscherlich produced it via the distillation of benzoic acid (from gum benzoin) and lime. Mitscherlich gave the compound the name benzin.[4] In 1836 the French chemist Auguste Laurent named the substance "phène"; this is the root of the word phenol, which is hydroxylated benzene, and phenyl, which is the radical formed by abstraction of a hydrogen atom from benzene. Benzoin resin or styrax resin is a balsamic resin obtained from the bark of several species of trees in the genus Styrax. ... Michael Faraday, FRS (September 22, 1791 – August 25, 1867) was an English chemist and physicist (or natural philosopher, in the terminology of that time) who contributed to the fields of electromagnetism and electrochemistry. ... Linus Carl Pauling (February 28, 1901 – August 19, 1994) was an American scientist, peace activist, author and educator of German ancestry. ... Eilhard Mitscherlich Eilhard Mitscherlich (1794-1863), is most known for his discovery of the principle of isomorphism. ... Laboratory distillation set-up: 1: Heat source 2: Still pot 3: Still head 4: Thermometer/Boiling point temperature 5: Condenser 6: Cooling water in 7: Cooling water out 8: Distillate/receiving flask 9: Vacuum/gas inlet 10: Still receiver 11: Heat control 12: Stirrer speed control 13: Stirrer/heat plate... Benzoic acid, C7H6O2 (or C6H5COOH), is a colorless crystalline solid and the simplest aromatic carboxylic acid. ... Commonly called benzoin, it is called benzoin resin here to distinguish it from the crystalline compound benzoin. ... Calcium oxide (CaO), commonly known as lime, quicklime or burnt lime, is a widely used chemical compound. ... Auguste Laurent (November 14, 1807 _ April 23, 1853) was a French chemist who discovered anthracene, discovered phthalic acid, and identified carbolic acid. ... Phenol, also known under an older name of carbolic acid, is a colourless crystalline solid with a typical sweet tarry odor. ... In chemistry, the phenyl group or phenyl ring (often abbreviated as -Ph) is the functional group with the formula -C6H5 Picture where the six carbon atoms are arranged in a cyclic manner. ...


In 1845, Charles Mansfield, working under August Wilhelm von Hofmann, isolated benzene from coal tar. Four years later, Mansfield began the first industrial-scale production of benzene, based on the coal-tar method. August Wilhelm von Hofmann (April 8, 1818 _ May 5, 1892) was a German chemist. ... Coal tar is the liquid by-product of the distillation of coal to make coke. ...


Gradually the sense developed among chemists that substances related to benzene formed a natural chemical family. In 1855 August Wilhelm Hofmann used the word "aromatic" to designate this family relationship, after a characteristic property of many of its members. August Wilhelm von Hofmann (April 8, 1818 _ May 5, 1892) was a German chemist. ... In chemistry, an aromatic molecule is one in which electrons are free to cycle around circular arrangements of atoms, which are alternately singly and doubly bonded to one another. ...


Ring formula

The empirical formula for benzene was long known, but its highly polyunsaturated structure was challenging to determine. Archibald Scott Couper in 1858 and Joseph Loschmidt in 1861 suggested possible structures that contained multiple double bonds or multiple rings, but the study of aromatic compounds was in its very early years, and too little evidence was then available to help chemists decide on any particular structure. In chemistry, saturation has four different meanings: In physical chemistry, saturation is the point at which a solution of a substance can dissolve no more of that substance and additional amounts of that substance will appear as a precipitate. ... Archibald Scott Couper (1831-1892) was the author of On a New Chemical Theory, Philosophical Magazine 16, 104-116 (1858) [as excerpted in Alembic Club Reprint #21, On a New Chemical Theory and Researches on Salicylic Acid[1]] Friedrich August Kekulé von Stradonitz claimed to solve the structure of Benzene... Jan or Johann Josef Loschmidt (March 15, 1821 - July 8, 1895) who referred to himself mostly as Josef Loschmidt (omitting his first name), was a notable Austrian scientist with groundbreaking work in the fields of chemistry and physics (thermodynamics, optics, electrodynamics). ...


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 six-membered ring of carbon atoms with alternating single and double bonds. The next year he published a much longer paper in German on the same subject.[5][6] 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 diderivative—to argue in support of his proposed structure. Kekulé's symmetrical ring could explain these curious facts. Friedrich August Kekulé von Stradonitz Friedrich August Kekulé von Stradonitz (September 7, 1829 – July 13, 1896) was a German organic chemist. ... In chemistry, isomers are molecules with the same chemical formula and often with the same kinds of chemical bonds between atoms, but in which the atoms are arranged differently (analogous to a chemical anagram). ... Derivative (Chemistry) In chemistry a derivative is a compound that is formed from a similar compound. ...


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. Here Kekulé spoke of the creation of the theory. He said that he had discovered the ring shape of the benzene molecule after having a reverie or day-dream of a snake seizing its own tail (this is a common symbol in many ancient cultures known as the Ouroboros). This vision, he said, came to him after years of studying the nature of carbon-carbon bonds. This was 20 years after he had solved the problem of how carbon atoms could bond to up to four other atoms at the same time. It is curious that a similar humorous depiction of benzene had appeared in 1886 in the 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.[7] Some historians have suggested that the parody was a lampoon of the snake anecdote, possibly already well-known through oral transmission even if it had not yet appeared in print.[1] Others have speculated that Kekulé's story in 1890 was a re-parody of the monkey spoof, and was a mere invention rather than a recollection of an event in his life. (sickness) (noobish) For other uses, see Ouroboros (disambiguation). ...


Kekulé's 1890 speech[8] in which these anecdotes appeared has been translated into English.[9] If one takes the anecdote as the memory of a real event, circumstances mentioned in the story suggest that it must have happened early in 1862.[10]


The cyclic nature of benzene was finally confirmed by the crystallographer Kathleen Lonsdale.[11][12] Dame Kathleen Lonsdale (January 28, 1903 - April 1, 1971) was a prominent crystallographer, who discovered the planar hexagonal structure of benzene. ...


Structure

Main article: aromaticity

Benzene represents a special problem in that, to account for all the bonds, there must be alternating double carbon bonds: Aromaticity is a chemical property in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone. ... Covalent bonding is a form of chemical bonding characterized by the sharing of one or more pairs of electrons between atoms, in order to produce a mutual attraction, which holds the resultant molecule together. ...


Benzene with alternating double bonds Chemical structure of benzene Selfmade by cacycle File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...


Using X-ray diffraction, researchers discovered that all of the carbon-carbon bonds in benzene are of the same length of 140 picometres (pm). The C–C bond lengths are greater than a double bond (135pm) but shorter than a single bond (147pm). This intermediate distance is explained by electron delocalization: the electrons for C–C bonding are distributed equally between each of the six carbon atoms. One representation is that the structure exists as a superposition of so-called resonance structures, rather than either form individually. This delocalisation of electrons is known as aromaticity, and gives benzene great stability. This enhanced stability is the fundamental property of aromatic molecules that differentiates them from molecules that are non-aromatic. To reflect the delocalised nature of the bonding, benzene is often depicted with a circle inside a hexagonal arrangement of carbon atoms: X-ray crystallography is a technique in crystallography in which the pattern produced by the diffraction of x-rays through the closely spaced lattice of atoms in a crystal is recorded and then analyzed to reveal the nature of that lattice. ... One picometre is defined as 1x10-12 metres, in standard units. ... In molecular geometry, bond length or bond distance is the distance between two bonded atoms in a molecule. ... In chemistry, delocalized electrons are electrons in a molecule that do not belong to a single atom or a covalent bond. ... Resonance structures are diagrammatic tools in organic chemistry to symbolize resonant bonds between atoms in molecules. ... Aromaticity is a chemical property in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone. ...


Benzene structure with a circle inside the hexagon Chemical structure of benzene Selfmade by cacycle Old version: File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...


As is common in organic chemistry, the carbon atoms in the diagram above have been left unlabeled. Realising each carbon has 2p electrons, each carbon donates 1p electron into the delocalised ring above and below the benzene ring. It is the side-on overlap of p-orbitals that produces the pi clouds.


Benzene occurs sufficiently often as a component of organic molecules that there is a Unicode symbol with the code 232C to represent it with three double bonds, and 23E3 for a delocalized version [13]. The Unicode Standard, Version 5. ...


Substituted benzene derivatives

Main article: Aromatic hydrocarbons

Many important chemicals are derived from benzene, wherein with one or more of the hydrogen atoms is replaced with another functional group. Examples of simple benzene derivatives are phenol, toluene, and aniline, abbreviated PhOH, PhMe, and PhNH2, respectively. Linking benzene rings gives biphenyl, C6H5–C6H5. Further loss of hydrogen gives "fused" aromatic hydrocarbons, such as naphthalene and anthracene. The limit of the fusion process is the hydrogen-free material graphite. An aromatic hydrocarbon (abbreviated as AH), or arene is a hydrocarbon, the molecular structure of which incorporates one or more planar sets of six carbon atoms that are connected by delocalised electrons numbering the same as if they consisted of alternating single and double covalent bonds. ... In organic chemistry, functional groups (or moieties) are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules. ... Phenol, also known under an older name of carbolic acid, is a colourless crystalline solid with a typical sweet tarry odor. ... Toluene, also known as methylbenzene or phenylmethane is a clear, water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. ... Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. ... Biphenyl (or Diphenyl or 1,1-Biphenyl or lemonene) is a solid compound that forms colourless to yellowish crystals. ... R-phrases , , S-phrases , , , , Flash point 79 - 87 °C Autoignition temperature 525 °C Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Naphthalene (not to be confused with naphtha) (also known as naphthalin, naphthaline, moth ball, tar... In chemistry, anthracene is a solid polycyclic aromatic hydrocarbon consisting of three benzene rings derived from coal-tar. ... For other uses, see Graphite (disambiguation). ...


In heterocycles, carbon atoms in the benzene ring are replaced with other elements. The most important derivatives are the rings containing nitrogen. Replacing one CH with N gives the compound pyridine, C5H5N. Although benzene and pyridine are structurally related, benzene cannot be converted into pyridine. Replacement of a second CH bond with N gives, depending on the location of the second N, pyridazine, pyrimidine, and pyrazine. Pyridine a simple heterocyclic compound Heterocyclic compounds are organic compounds that contain a ring structure containing atoms in addition to carbon, such as sulfur, oxygen or nitrogen, as part of the ring. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... Pyridine is a chemical compound with the formula C5H5N. It is a liquid with a distinctively putrid odour. ... Pyridazine is a heteroaromatic organic compound with the molecular formula C4H4N2. ... Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring [1]. It is isomeric with two other forms of diazine. ... Pyrazine is a symmetrical molecule. ...


Production

Trace amounts of benzene may result whenever carbon-rich materials undergo incomplete combustion. It is produced in volcanoes and forest fires, and is also a component of cigarette smoke. For other uses, see Carbon (disambiguation). ... This article is about the chemical reaction combustion. ... Cleveland Volcano in the Aleutian Islands of Alaska photographed from the International Space Station For other uses, see Volcano (disambiguation). ... Fire in San Bernardino, California Mountains (image taken from the International Space Station) A wildfire, also known as a forest fire, vegetation fire, grass fire, or bushfire (in Australasia), is an uncontrolled fire in wildland often caused by lightning; other common causes are human carelessness and arson. ... Unlit filtered cigarettes. ...


Up until World War II, most benzene was produced as a byproduct of coke production (or "coke-oven light oil") in the steel industry. However, in the 1950s, increased demand for benzene, especially from the growing plastics industry, necessitated the production of benzene from petroleum. Today, most benzene comes from the petrochemical industry, with only a small fraction being produced from coal. Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... Coke Coke is a solid carbonaceous material derived from destructive distillation of low-ash, low-sulfur bituminous coal. ... For other uses, see Steel (disambiguation). ... For other uses, see Plastic (disambiguation). ... Petrochemicals are chemical products made from raw materials of petroleum (hydrocarbon) origin. ...


Three chemical processes contribute to industrial benzene production: catalytic reforming, toluene hydrodealkylation, and steam cracking. In the US, 50% of benzene comes from catalytic reforming and 25% from steam cracking. In Western Europe, 50% of benzene comes from steam cracking and 25% from catalytic reforming. Catalytic reforming is a chemical process used to convert petroleum refinery naphthas, typically having low octane ratings, into high-octane liquid products called reformates which are components of high-octane gasoline (also known as petrol). ... Toluene, also known as methylbenzene or phenylmethane is a clear, water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. ... In petroleum geology and chemistry, cracking is the process whereby complex organic molecules (e. ... Catalytic reforming is a chemical process used to convert petroleum refinery naphthas, typically having low octane ratings, into high-octane liquid products called reformates which are components of high-octane gasoline (also known as petrol). ... In petroleum geology and chemistry, cracking is the process whereby complex organic molecules (e. ... In petroleum geology and chemistry, cracking is the process whereby complex organic molecules (e. ... Catalytic reforming is a chemical process used to convert petroleum refinery naphthas, typically having low octane ratings, into high-octane liquid products called reformates which are components of high-octane gasoline (also known as petrol). ...


Catalytic reforming

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. Under these conditions, aliphatic hydrocarbons form rings and lose hydrogen to become aromatic hydrocarbons. The aromatic products of the reaction are then separated from the reaction mixture (or reformate) by extraction with any one of a number of solvents, including diethylene glycol or sulfolane, and benzene is then separated from the other aromatics by distillation. The extraction step of aromatics from the reformate is designed to produce aromatics with lowest non-aromatic components. So-called "BTX (Benzene-Toluene-Xylenes)" process consists of such extraction and distillation steps. Look up Hydrocarbon in Wiktionary, the free dictionary. ... This article is about the chemistry of hydrogen. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... General Name, Symbol, Number rhenium, Re, 75 Chemical series transition metals Group, Period, Block 7, 6, d Appearance grayish white Standard atomic weight 186. ... It has been suggested that this article or section be merged into Catalysis. ... In chemistry, non-aromatic and non-cyclic (acyclic) organic compounds are called aliphatic. ... Liquid-liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds based on their solution preferences for two different immiscible liquids, usually water and an organic solvent. ... For other uses, see Solvent (disambiguation). ... Diethylene glycol (DEG) is an organic compound described by the structural formula HO-CH2-CH2-O-CH2-CH2-OH. It is a clear, hygroscopic, odorless liquid. ... Sulfolane (also tetramethylene sulfone, systematic name: 2,3,4,5-tetrahydrothiophene-1,1-dioxide) is a clear, colorless liquid commonly used in the chemical industry as an extractive distillation solvent or reaction solvent. ...


Similarly to this catalytic reforming, UOP and BP commercialized a method from LPG (mainly propane and butane) to aromatics. UOP is an initialism that may stand for the following: Urząd Ochrony Państwa, the Polish Intelligence agency User operation prohibition, a technique commonly used in commercial DVDs that prohibits user operation at certain times during playback (such as while a copyright notice is displayed) University of the Pacific... This article is about the energy corporation. ...


Toluene hydrodealkylation

Toluene hydrodealkylation converts toluene to benzene. In this hydrogen-intensive process, toluene is mixed with hydrogen, then passed over a chromium, molybdenum, or platinum oxide catalyst at 500–600 °C and 40–60 atm pressure. Sometimes, higher temperatures are used instead of a catalyst (at the similar reaction condition). Under these conditions, toluene undergoes dealkylation according to the chemical equation: Toluene, also known as methylbenzene or phenylmethane is a clear, water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. ... REDIRECT [[ Insert text]]EWWWWWWWWWWWWW YO General Name, symbol, number chromium, Cr, 24 Chemical series transition metals Group, period, block 6, 4, d Appearance silvery metallic Standard atomic weight 51. ... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Standard atomic weight 95. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... An oxide is a chemical compound containing at least one oxygen atom and other elements. ... A chemical equation is a symbolic representation of a chemical reaction. ...

C6H5CH3 + H2 → C6H6 + CH4

This irreversible reaction is accompanied by an equilibrium side reaction that produces biphenyl (aka diphenyl) at higher temperature: 2 C6H6 ↔ H2 + C12H10 Toluene, also known as methylbenzene or phenylmethane is a clear, water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. ... This article is about the chemistry of hydrogen. ... Methane is a chemical compound with the molecular formula . ... Biphenyl (or Diphenyl or 1,1-Biphenyl or lemonene) is a solid compound that forms colourless to yellowish crystals. ...


If the raw material stream contains much non-aromatic components (paraffins or naphthenes), those are likely decomposed to lower hydrocarbons such as methane, which increases the consumption of hydrogen.


A typical reaction yield exceeds 95%. Sometimes, xylenes and heavier aromatics are used in place of toluene, with similar efficiency. The term xylenes refers to a group of 3 benzene derivatives which encompasses ortho-, meta-, and para- isomers of dimethyl benzene. ...


This is often called "on-purpose" methodology to produce benzene, compared to conventional BTX (benzene-toluene-xylene) processes. The hydrodealkylation process is not economically feasible if the price gap between benzene and toluene is small (or the gap is smaller than about 15% of benzene price).


Toluene disproportionation

Where a chemical complex has similar demands for both benzene and xylene, then toluene disproportionation (TDP) may be an attractive alternative to the toluene hydrodealkylation. Broadly speaking 2 toluene molecules are reacted and the methyl groups rearranged from one toluene molecule to the other, yielding one benzene molecule and one xylene molecule. The term xylenes refers to a group of 3 benzene derivatives which encompasses ortho-, meta-, and para- isomers of dimethyl benzene. ... Disproportionation is a concept in chemistry and is a redox reaction where a reactant is both oxidised and reduced in the same chemical reaction. ...


Given that demand for para-xylene (p-xylene) substantially exceeds demand for other xylene isomers, a refinement of the TDP process called Selective TDP (STDP) may be used. In this process, the xylene stream exiting the TDP unit is approximately 90% paraxylene. In some current catalytic systems, even the benzene-to-xylenes ratio is decreased (more xylenes) when the demand of xylenes is higher. p-Xylene is an aromatic hydrocarbon, based on benzene with two methyl substituents. ...


Steam cracking

Steam cracking is the process for producing ethylene and other olefins from aliphatic hydrocarbons. Depending on the feedstock used to produce the olefins, steam cracking can produce a benzene-rich liquid byproduct called pyrolysis gasoline. Pyrolysis gasoline can be blended with other hydrocarbons as a gasoline additive, or distilled (in BTX process) to separate it into its components, including benzene. In petroleum geology and chemistry, cracking is the process whereby complex organic molecules (e. ... Ethylene (or IUPAC name ethene) is the chemical compound with the formula C2H4. ... A synonym for the more widely accepted term, alkene. ... In chemistry, aliphatic compounds are organic compounds in which carbon atoms are joined together in straight or branched chains. ...


Uses

Early uses

In the 19th and early-20th centuries, benzene was used as an after-shave lotion because of its pleasant smell. Prior to the 1920s, benzene was frequently used as an industrial solvent, especially for degreasing metal. As its toxicity became obvious, benzene was supplanted by other solvents, especially toluene (methyl benzene), which has similar physical properties but is not as carcinogenic. Toluene, also known as methylbenzene or phenylmethane is a clear, water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. ...


In 1903, Ludwig Roselius popularized the use of benzene to decaffeinate coffee. This discovery led to the production of Sanka (the letters "ka" in the brand name stand for kaffein). This process was later discontinued. To meet Wikipedias quality standards, this article or section may require cleanup. ...


As a petrol additive, benzene increases the octane rating and reduces knocking. Consequently, petrol often contained several percent benzene before the 1950s, when tetraethyl lead replaced it as the most widely-used antiknock additive. With the global phaseout of leaded petrol, benzene has made a comeback as a gasoline additive in some nations. In the United States, concern over its negative health effects and the possibility of benzene entering the groundwater have led to stringent regulation of petrol's benzene content, with limits typically around 1%. European petrol specifications now contain the same 1% limit on benzene content. The US EPA has new regulations that will lower the benzene content in gasoline to 0.62% in 2011.[14] A gas station pump offering five different octane ratings. ... Knocking (also called pinking or pinging)— colloquially detonation—in internal combustion engines occurs when air/fuel mixture in the cylinder detonates or ignites prior to the timed pre-set conditions in the engines cylinder(s). ... Tetra-ethyl lead (also known as TEL, lead tetraethyl and tetraethyllead) is a toxic organometallic chemical compound, with formula (CH2CH3)4Pb, which was once used as a gasoline (petrol) additive. ... Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of lithologic formations. ...


Current uses of benzene

Today benzene is mainly used as an intermediate to make other chemicals. Its most widely-produced derivatives include styrene, which is used to make polymers and plastics, phenol for resins and adhesives (via cumene), and cyclohexane, which is used in the manufacture of Nylon. Smaller amounts of benzene are used to make some types of rubbers, lubricants, dyes, detergents, drugs, explosives, napalm and pesticides. C8H8 redirects here. ... Phenol, also known under an older name of carbolic acid, is a colourless crystalline solid with a typical sweet tarry odor. ... Cumene is the trivial name for isopropylbenzene, an organic chemical compound that is an aromatic hydrocarbon. ... Cyclohexane is a cycloalkane with the molecular formula C6H12. ... This does not cite any references or sources. ... A lubricant (colloquially, lube) is a substance (often a liquid) introduced between two moving surfaces to reduce the friction and wear between them. ... Look up dye in Wiktionary, the free dictionary. ... Laundry detergents are just one of many possible uses for detergents Detergent is a compound, or a mixture of compounds, intended to assist cleaning. ... For other uses, see Drug (disambiguation). ... This article is concerned solely with chemical explosives. ... A simulated Napalm explosion during MCAS Air Show in 2003. ... A cropduster spreading pesticide. ...


In both US and Europe, 50% of benzene is used in the production of ethylene benzene/styrene, 20% is used in the production of cumene, and about 15% of benzene is used in the production of cyclohexane (eventually to Nylon).


In laboratory research, toluene is now often used as a substitute for benzene. The solvent-properties of the two are similar but toluene is less toxic and has a wider liquid range. Toluene, also known as methylbenzene or phenylmethane is a clear, water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. ...


Benzene has been used as a basic research tool in a variety of experiments including analysis of a two-dimensional gas A two-dimensional gas is a collection of N objects which are constrained to move in a planar or other two-dimensional space in a gaseous state. ...


Reactions of benzene

Electrophilic aromatic substitution of benzene
Friedel-Crafts acylation of benzene by acetyl chloride
Friedel-Crafts alkylation of benzene with methyl chloride
    • Like the Friedel-Crafts acylation, the Friedel-Crafts alkylation involves the alkylation of benzene (and many other aromatic rings) using an alkyl halide in the presence of a strong Lewis acid catalyst.
    • sulfonation.
    • Nitration: Benzene undergoes nitration with nitronioum ions (NO2+) as the electrophile. Thus, warming benzene at 50-55 degrees Celsius, with a combination of concentrated sulfuric and nitric acid to produce the electrophile, gives nitrobenzene.
  • Hydrogenation(Reduction): Benzene and derivatives convert to cyclohexane and derivatives when treated with hydrogen at 450 K and 10 atm of pressure with a finely divided nickel catalyst.
  • Benzene is an excellent ligand in the organometallic chemistry of low-valent metals. Important examples include the sandwich and half-sandwich complexes respectively Cr(C6H6)2 and [RuCl2(C6H6)]2.

Image File history File links File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Electrophilic aromatic substitution or EAS is an organic reaction in which an atom, usually hydrogen, appended to an aromatic system is replaced by an electrophile. ... In chemistry, a nucleophile (literally nucleus lover) is a reagent which is attracted to centres of positive charge. ... An acyl group is a functional group derived by the removal of one or more hydroxyl group from an oxoacid. ... A carbocation (IPA pronunciation: ) is an ion with a positively-charged carbon atom. ... Friedel-Crafts acylation of benzene. ... The Friedel-Crafts reactions were developed by Charles Friedel and James Crafts in 1877. ... Electrophilic aromatic substitution or EAS is an organic reaction in which an atom, usually hydrogen, appended to an aromatic system is replaced by an electrophile. ... In chemistry, acylation is the process of adding an acyl group to a compound. ... General Chemical Structure of an Acyl Chloride In organic chemistry, an acyl chloride (or acid chloride) is an organic compound which is a reactive derivative of a carboxylic acid. ... In chemistry, a Lewis acid can accept a pair of electrons and form a coordinate covalent bond, after the American chemist Gilbert Lewis. ... It has been suggested that this article or section be merged into Catalysis. ... Aluminium chloride (AlCl3) is a compound of aluminium and chlorine. ... R-phrases , S-phrases , Related Compounds Other anions Iron(III) fluoride Iron(III) bromide Other cations Iron(II) chloride Manganese(II) chloride Cobalt(II) chloride Ruthenium(III) chloride Related coagulants Iron(II) sulfate Polyaluminium chloride Except where noted otherwise, data are given for materials in their standard state (at 25... friedel-craft-alkylation File links The following pages link to this file: Friedel-Crafts reaction Categories: GFDL images ... The Friedel-Crafts reactions were developed by Charles Friedel and James Crafts in 1877. ... Alkylation is the transfer of an alkyl group from one molecule to another. ... In chemistry, an alkyl halide is an organic molecule of the form R_X, where X is a halide and R contains a carbon atom bonded to other functional groups or hydrogens. ... Aromatic sulfonation is an organic reaction in which a hydrogen atom on an arene is replaced by a sulfonic acid functional group in an electrophilic aromatic substitution. ... Nitration is a general chemical process for the introduction of a nitro group in a chemical compound by means of a chemical reaction. ... Hydrogenation is a class of chemical reactions which result an addition of hydrogen (H2) usually to unsaturated organic compounds. ... For other uses, see Nickel (disambiguation). ... It has been suggested that this article or section be merged into Catalysis. ... Synthesis of copper(II)-tetraphenylporphine, a metal complex, from tetraphenylporphine and copper(II) acetate monohydrate. ... Bis(benzene)chromium is the chemical compound with the formula Cr(η6-C6H6)2. ...

Health effects

Benzene exposure has serious health effects. Breathing high levels of benzene can result in death, while low levels can cause drowsiness, dizziness, rapid heart rate, headaches, tremors, confusion, and unconsciousness. Eating or drinking foods containing high levels of benzene can cause vomiting, irritation of the stomach, dizziness, sleepiness, convulsions, and death. Health effects, health impacts or health risks are an important consideration in many areas, such as hygiene, pollution studies, workplace safety, nutrition and health sciences in general. ... For other uses, see Death (disambiguation). ... A headache (cephalgia in medical terminology) is a condition of pain in the head; sometimes neck or upper back pain may also be interpreted as a headache. ... Fred Ward as Earl Bassett in the 1990 film Tremors. ... In anatomy, the stomach is a bean-shaped hollow muscular organ of the gastrointestinal tract involved in the second phase of digestion, following mastication. ...


The major effects of benzene are chronic (long-term) exposure through the blood. Benzene damages the bone marrow and can cause a decrease in red blood cells, leading to anemia. It can also cause excessive bleeding and depress the immune system, increasing the chance of infection. In medicine, a chronic disease is a disease that is long-lasting or recurrent. ... For other uses, see Blood (disambiguation). ... For the Dir en grey album, see The Marrow of a Bone. ... This article discusses the medical condition. ... A scanning electron microscope image of a single neutrophil (yellow), engulfing anthrax bacteria (orange). ... An infection is the detrimental colonization of a host organism by a foreign species. ...


Some women who breathed high levels of benzene for many months had irregular menstrual periods and a decrease in the size of their ovaries. It is not known whether benzene exposure affects the developing fetus in pregnant women or fertility in men. Not to be confused with Mensuration. ... Human female internal reproductive anatomy Ovaries are a part of a female organism that produces eggs. ... For other uses, see Fetus (disambiguation). ...


Animal studies have shown low birth weights, delayed bone formation, and bone marrow damage when pregnant animals breathed benzene.


Benzene has been connected to a rare form of kidney cancer in two separate studies, one involving tank truck drivers, and the other involving seamen on tanker vessels, both carrying benzene laden chemicals.


The US Department of Health and Human Services (DHHS) classifies benzene as a human carcinogen. Long-term exposure to high levels of benzene in the air can cause leukemia, a potentially fatal cancer of the blood-forming organs. In particular, Acute myeloid leukemia or acute non-lymphocytic leukaemia (AML & ANLL) may be caused by benzene. The United States Department of Health and Human Services, often abbreviated HHS, is a Cabinet department of the United States government with the goal of protecting the health of all Americans and providing essential human services. ... Look up carcinogen in Wiktionary, the free dictionary. ... Leukemia or leukaemia (Greek leukos λευκός, white; aima αίμα, blood) is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells (leukocytes). ... Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... Acute myeloid leukemia (AML), also known as acute myelogenous leukemia, is a cancer of the myeloid line of white blood cells, characterized by the rapid proliferation of abnormal cells which accumulate in the bone marrow and interfere with the production of normal blood cells. ...


Several tests can determine exposure to benzene. There is a test for measuring benzene in the breath; this test must be done shortly after exposure. Benzene can also be measured in the blood; however, because benzene disappears rapidly from the blood, measurements are accurate only for recent exposures.


In the body, benzene is metabolized. Certain metabolites, such as trans,trans-muconic acid can be measured in the urine. However, this test must be done shortly after exposure and is not a reliable indicator of benzene exposure, since the same metabolites may be present in urine from other sources. Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ... This article is about the urine of animals generally. ...


The United States Environmental Protection Agency has set the maximum permissible level of benzene in drinking water at 0.005 milligrams per liter (0.005 mg/L). The EPA requires that spills or accidental releases into the environment of 10 pounds (4.5 kg) or more of benzene be reported to the EPA. EPA redirects here. ...


The US Occupational Safety and Health Administration (OSHA) has set a permissible exposure limit of 0.5 part of benzene per million parts of air (.5 ppm) in the workplace during an 8-hour workday, 40-hour workweek. The short term exposure limit for airborne benzene is 5 ppm for 15 minutes. OSHA logo The United States Occupational Safety and Health Administration (OSHA) is an agency of the United States Department of Labor. ...


In recent history there have been many examples of the harmful health effects of benzene and its derivatives. Toxic Oil Syndrome caused localised immune-suppression in Madrid in 1981 from people ingesting anilide-contaminated rapeseed oil. Chronic Fatigue Syndrome has also been correlated with people who eat "denatured" food that use solvents to remove fat or contain benzoic acid but causality is unproven. Toxic Oil Syndrome was the name given to an unusual disease outbreak in Spain in 1981. ... This article is about the Spanish capital. ... Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. ... Binomial name Brassica napus L. Rapeseed Brassica napus, also known as Rape, Oilseed Rape, Rapa, Rapaseed and (one particular cultivar) Canola, is a bright yellow flowering member of the family Brassicaceae. ... Chronic fatigue syndrome (CFS) is one of several names given to a poorly understood, highly debilitating disorder of uncertain cause/causes, which is thought to affect approximately 4 per 1,000 adults[1] in the United States and other countries, and a smaller fraction of children. ... Benzoic acid, C7H6O2 (or C6H5COOH), is a colorless crystalline solid and the simplest aromatic carboxylic acid. ...


Workers in various industries that make or use benzene may be at risk for being exposed to high levels of this carcinogenic chemical. Industries that involve the use of benzene include the rubber industry, oil refineries, chemical plants, shoe manufacturers, and gasoline related industries. In 1987, OSHA estimated that about 237,000 workers in the United States were potentially exposed to benzene, and it is not known if this number has substantially changed since then. This does not cite any references or sources. ... Petrol redirects here. ... OSHA logo The United States Occupational Safety and Health Administration (OSHA) is an agency of the United States Department of Labor. ...


Water and soil contamination are important pathways of concern for transmission of benzene contact. In the U.S. alone there are approximately 100,000 different sites which have benzene soil or groundwater contamination. In 2005, the water supply to the city of Harbin in China with a population of almost nine million people, was cut off because of a major benzene exposure. Benzene leaked into the Songhua River, which supplies drinking water to the city, after an explosion at a China National Petroleum Corporation (CNPC) factory in the city of Jilin on 13 November. Excavation of leaking underground storage tank causing soil contamination Soil pollution comprises the pollution of soils with materials, mostly chemicals, that are out of place or are present at concentrations higher than normal which may have adverse effects on humans or other organisms. ... Harbin on a map of China For other meanings of Harbin, see Harbin (disambiguation). ... The location of the Jilin Province of China. ... Location of the Songhua River is in dark blue. ... is the 317th day of the year (318th in leap years) in the Gregorian calendar. ...


In March 2006, the official Food Standards Agency in Britain conducted a survey of 150 brands of soft drinks. It found that four contained benzene levels above World Health Organization limits. The affected batches were removed from sale. See benzene in soft drinks[15] The Food Standards Agency is a non-ministerial government department of the Government of the United Kingdom. ... WHO redirects here. ... // Background Benzene is a carcinogen. ...


Biological oxidation and carcinogenic activity

One way of understanding the carcinogenic effects of benzene is by examining the products of biological oxidation. Pure benzene, for example, oxidizes in the body to produce an epoxide, benzene oxide, which is not excreted readily and can interact with DNA to produce harmful mutations.


References

  1. ^ a b A. J. Rocke (1985). "Hypothesis and Experiment in the Early Development of Kekule's Benzene Theory". Annals of Science 42: 355–81. doi:10.1080/00033798500200411. 
  2. ^ M. Faraday (1825). "On New Compounds of Carbon and Hydrogen, and on Certain Other Products Obtained during the Decomposition of Oil by Heat". Philosophical Transactions of the Royal Society of London 115: 440–466. 
  3. ^ R. Kaiser (1968). "Bicarburet of Hydrogen. Reappraisal of the Discovery of Benzene in 1825 with the Analytical Methods of 1968". Angewandte Chemie International Edition in English 7 (5): 345–350. doi:10.1002/anie.196803451. 
  4. ^ E. Mitscherlich (1834). "Ueber das Benzol und die Säuren der Oel- und Talgarten". Annalen der Pharmacie 9 (1): 39–48. doi:10.1002/jlac.18340090103. 
  5. ^ F. A. Kekulé (1865). "Sur la constitution des substances aromatiques". Bulletin de la Societe Chimique de Paris 3: 98–110. 
  6. ^ F. A. Kekulé (1866). "Untersuchungen uber aromatische Verbindungen". Liebigs Annalen der Chemie 137: 129–36. doi:10.1002/jlac.18661370202. 
  7. ^ Translated into English by D. Wilcox and F. Greenbaum, Journal of Chemical Education, 42 (1965), 266–67.
  8. ^ F. A. Kekulé (1890). "Benzolfest: Rede". Berichte der Deutschen Chemischen Gesellschaft 23: 1302–11. 
  9. ^ O. T. Benfey, "August Kekulé and the Birth of the Structural Theory of Organic Chemistry in 1858," Journal of Chemical Education, 35 (1958), 21–23
  10. ^ Jean Gillis, "Auguste Kekulé et son oeuvre, realisee a Gand de 1858 a 1867," Memoires de l'Academie Royale de Belgique, 37:1 (1866), 1–40.
  11. ^ K. Lonsdale (1929). "The Structure of the Benzene Ring in Hexamethylbenzene". Proceedings of the Royal Society 123A: 494. 
  12. ^ K. Lonsdale (1931). "An X-Ray Analysis of the Structure of Hexachlorobenzene, Using the Fourier Method". Proceedings of the Royal Society 133A: 536–553. 
  13. ^ Many fonts do not have these Unicode characters, so many programs may not be able to display them correctly. A graphical representation of the first symbol can be found at the following URL: http://www.fileformat.info/info/unicode/char/232c/index.htm
  14. ^ Kolmetz, Gentry, Guidelines for BTX Revamps, AIChE 2007 Spring Conference
  15. ^ "FDA: Too Much Benzene In Some Drinks", CBS News, May 19, 2006, retrieved July 11, 2006

A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Michael Faraday, FRS (September 22, 1791 – August 25, 1867) was an English chemist and physicist (or natural philosopher, in the terminology of that time) who contributed to the fields of electromagnetism and electrochemistry. ... Cover of Cover of the first volume of , published in 1665 The Philosophical Transactions of the Royal Society, or Phil. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Justus Liebigs Annalen der Chemie (often cited as just Liebigs Annalen) was one of the oldest and most historically important chemistry journals worldwide. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Friedrich August Kekulé von Stradonitz Friedrich August Kekulé von Stradonitz (September 7, 1829 – July 13, 1896) was a German organic chemist. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Dame Kathleen Lonsdale (January 28, 1903 - April 1, 1971) was a prominent crystallographer, who discovered the planar hexagonal structure of benzene. ... Cover of Proceedings of the Royal Society is a scientific journal published by the Royal Society of London. ... Cover of Proceedings of the Royal Society is a scientific journal published by the Royal Society of London. ... is the 139th day of the year (140th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 192nd day of the year (193rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ...

External links

Wikimedia Commons has media related to:
Look up benzene in Wiktionary, the free dictionary.

Wikipedia does not have an article with this exact name. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 151 languages. ... PubChem is a database of chemical molecules. ... In ecology functional groups are collections of organisms based on morphological, physiological, behavioral, biochemical, or environmental responses or on trophic criteria. ... Chemical classification systems attempt to classify elements or compounds according to certain chemical functional or structural properties. ... This article does not cite any references or sources. ... An aldehyde. ... Chemical structure of methane, the simplest alkane Alkanes, also known as Paraffins, are chemical compounds that consist only of the elements carbon (C) and hydrogen (H) (i. ... This article is about the chemical compound. ... The structural formula of 2-butyne, a simple alkyne-containing molecule Alkynes are hydrocarbons that have at least one triple bond between two carbon atoms, with the formula CnH2n-2. ... Amide functional group Amides possess a conjugated system spread over the O, C and N atoms, consisting of molecular orbitals occupied by delocalized electrons. ... The general structure of an amine Amines are organic compounds and a type of functional group that contain nitrogen as the key atom. ... Azo compounds refer to chemical compounds bearing the functional group R-N=N-R, in which R and R can be either aryl or alkyl. ... Structure of a carboxylic acid The 3D structure of the carboxyl group A space-filling model of the carboxyl group Carboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the formula -C(=O)OH, usually written -COOH or -CO2H. [1] Carboxylic acids are Bronsted... The cyanate ion is an anion consisting of one oxygen atom, one carbon atom, and one nitrogen atom (OCN−), in that order, and possesses 1 unit of negative charge, borne mainly by the nitrogen atom. ... In chemistry, a disulfide bond is a single covalent bond derived from the coupling of thiol groups. ... For other uses, see Ester (disambiguation). ... This article is about a general class of chemical compounds. ... Tetrafluoroethane (a haloalkane) is a clear liquid which boils well below room temperature (as seen here) and can be extracted from common canned air canisters by simply inverting them during use. ... Benzophenone hydrazone, an example hydrazone In chemistry, a hydrazone is a compound with the structure R2C=NNR2, differing from a ketone or aldehyde by the replacement of the double bonded oxygen with the =NNR2 functional group. ... The general structure of an imine An imine is a functional group or chemical compound containing a carbon-nitrogen double bond. ... An isocyanide (erroneously called isonitrile) is a functional group in organic synthesis containing carbon and nitrogen. ... Isocyanate is the chemical group of atoms -N=C=O (1 nitrogen, 1 carbon, 1 oxygen), as opposed to cyanate, -O-C≡N, which is formed from cyanogen in the normal -ate manner. ... Ketone group A ketone (pronounced as key tone) is either the functional group characterized by a carbonyl group (O=C) linked to two other carbon atoms or a chemical compound that contains this functional group. ... An oxime is one in a class of chemical compounds with the general formula R1R2 C N O H, where R1 is an organic side chain and R2 is either hydrogen, forming an aldoxime, or another organic group, forming a ketoxime. ... A nitrile is any organic compound which has a -C≡N functional group. ... Nitro compounds are organic compounds that contain one or more nitro functional groups (-NO2). ... Nitroso refers to a functional group in organic chemistry which has the general formula R-NO. Nitroso compounds can be prepared by the reduction of nitro compounds or by the oxidation of hydroxylamines. ... The general structure of an organic peroxide. ... This article is about orthophosphoric acid. ... Pyridine is a chemical compound with the formula C5H5N. It is a liquid with a distinctively putrid odour. ... A sulfone is a chemical compound containing a sulfonyl functional group attached to two carbon atoms. ... It has been suggested that Sulfonic acid/Temp be merged into this article or section. ... A sulfoxide is a chemical compound containing a sulfinyl functional group with a sulfur oxygen double bond attached to two carbon atoms. ... General structure of a thioester. ... A thioether (similar to sulfide) is a functional group in organic chemistry that has the structure R1-S-R2 as shown on right. ... Sulphydryl // In organic chemistry, a thiol is a compound that contains the functional group composed of a sulfur atom and a hydrogen atom (-SH). ...


 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m