Cyclohexane
General
Molecular formula	C6H12
SMILES	C1CCCCC1
Molar mass	84.16 g/mol
Appearance and smell	Colourless liquid, greasy smell or petroleum
CAS number	[110-82-7]
Properties
Density and phase	0.779 g/ml, liquid
Solubility in water	Immiscible
Solubility in ethanol	Miscible
Melting point	6.55 °C (279.55 K)
Boiling point	80.74 °C (353.74 K)
Viscosity	1.02 cP at 17 °C
Index of refraction, nD	1.423
Thermodynamic data
Standard enthalpy of formation ΔfHoliquid	-156 kJ/mol
Standard enthalpy of combustion ΔcHoliquid	-3920 kJ/mol
Standard molar entropy Soliquid	? J.K−1.mol−1
Hazards
MSDS	External MSDS
EU classification	Flammable (F) Harmful (Xn) Dangerous for the environment (N) Severe eye irritant, may cause corneal clouding
Flash Point	-20 C
NFPA 704	Image File history File links No higher resolution available. ... Image File history File links Download high resolution version (1100x1199, 221 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Cyclohexane ... Image File history File links Size of this preview: 800 × 355 pixel Image in higher resolution (1104 × 490 pixel, file size: 8 KB, MIME type: image/png) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Cyclohexane ... Image File history File links Size of this preview: 702 × 600 pixel Image in higher resolution (1100 × 940 pixel, file size: 208 KB, MIME type: image/png) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Cyclohexane ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII strings. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... In physics, density is defined as mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: ρ (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... It has been suggested that this article or section be merged with Solution. ... This article describes water from a scientific and technical perspective. ... It has been suggested that this article or section be merged with Solution. ... Ethanol, also known as ethyl alcohol, drinking alcohol or grain alcohol, is a flammable, colorless, slightly toxic chemical compound with a distinctive perfume-like odor, and is the alcohol found in alcoholic beverages. ... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ... The boiling point of a substance is the temperature at which it can change its state from a liquid to a gas throughout the bulk of the liquid at a given pressure. ... The related Category:Units of viscosity has been nominated for deletion, merging, or renaming. ... The poise (P; IPA: ) is the unit of dynamic viscosity in the centimetre gram second system of units. ... The refractive index of a material is the factor by which electromagnetic radiation is slowed down (relative to vacuum) when it travels inside the material. ... The standard enthalpy of formation or standard heat of formation of a compound is the change of enthalpy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most stable form of the element at 1 atmosphere... Standard enthalpy of Combustion is the Enthalpy change when one mole of a substance is totally combusted in oxygen, and is measured at 298K and 1 atmospheric pressure. ... In chemistry, the standard molar entropy is the entropy content of one mole of substance, under conditions of standard temperature and pressure. ... An example MSDS in a US format provides guidance for handling a hazardous substance and information on its composition and properties. ... 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 source of European Union law concerning chemical safety. ... The flash point of a flammable liquid is the lowest temperature at which it can form an ignitable mixture with air. ... NFPA 704 is a standard maintained by the U.S. National Fire Protection Association. ... Image File history File links NFPA_704. ... 3 1 0
R-phrases	R11, R38, R65, R67, R50/53
S-phrases	S2, S9, S16, S25, S33, S60, S61, S62
Supplementary data page
Structure and properties	n, εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Regulatory data	Flash point, RTECS number, etc.
Related compounds
Related cycloalkanes	Cyclopentane Cycloheptane
Related compounds	Cyclohexene Benzene
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Cyclohexane is a cycloalkane with the molecular formula C₆H₁₂. Cyclohexane is used as a nonpolar solvent for the chemical industry, and also as a raw material for the industrial production of adipic acid and caprolactam, both of which are intermediates used in the production of nylon. Due to its unique chemical and conformational properties, cyclohexane is also used in labs in analysis and as a standard. 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. ... 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. ... 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. ... It has been suggested that NMR Data Processing be merged into this article or section. ... Mass spectrometry (also known as mass spectroscopy (deprecated)[1] or in common speech mass-spec) is an analytical technique used to measure the mass-to-charge ratio of ions. ... The flash point of a flammable liquid is the lowest temperature at which it can form an ignitable mixture with air. ... 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. ... cyclobutane Cycloalkanes are chemical compounds with a one or more rings of carbons to which hydrogens are attached according to the formula CnH2n. ... Cyclopentane is a highly flammable alicyclic hydrocarbon with chemical formula C5H10 and CAS number 287-92-3, consisting of a ring of five carbon atoms each bonded with two hydrogen atoms above and below the plane. ... Cycloheptane is a cycloalkane with the molecular formula C7H14. ... Cyclohexene is a colorless clear liquid cycloalkene with an intense aversive characteristic sharp smell reminiscent of an oil refinery. ... Benzene, also known as benzol, is an organic chemical compound with the formula C6H6. ... In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals) and 25 degrees Celsius (298. ... cyclobutane Cycloalkanes are chemical compounds with a one or more rings of carbons to which hydrogens are attached according to the formula CnH2n. ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... In chemistry, a nonpolar compound is one that does not have concentrations of positive or negative electric charge. ... A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ... Adipic acid is the common name of 1,6-hexanedioic acid, a chemical compound of the class of carboxylic acids. ... Caprolactam (C6H11ON) is the monomer used in the production of nylon 6. ... Nylon is a generic designation for a family of synthetic polymers first produced on February 28, 1935 by Gerard J. Berchet of Wallace Carothers research group at DuPont. ...

Chemical conformation

Main article: cyclohexane conformation

Contrary to popular belief, the 6 vertexed ring does not conform to the shape of a perfect hexagon. The conformation of a flat 2D planar hexagon has considerable angle strain due to the fact that its bonds are not 109.5 degrees; the torsional strain would also be considerable due to all eclipsed bonds. Therefore, to reduce torsional strain, cyclohexane adopts a three-dimensional structure known as the chair conformation. The new conformation puts the carbons at an angle of 109.5°. Half of the substituents are in the plane of the ring (equatorial) while the other half are perpendicular to the plane (axial). This conformation of substituents allows for the most stable structure of cyclohexane and its substituents. If cyclohexane is saturated with hydrogens with only one larger substituent attached the ring (called mono-substituted), then the larger substituent will most likely be found in the equatorial form, once again for the sake of stability. Though another form, known as boat conformation exists, it is somewhat unstable and usually reverts back to chair formation. Cyclohexane conformation is a much studied topic in organic chemistry because of the complex interrelationship between the different conformers of cyclohexane and its derivatives. ... In chemistry an eclipsed conformation is a chemical conformation that exists in any open chain single chemical bond connecting two sp3 hybridised atoms as a conformational energy maximum due to steric hindrance. ... The chair conformation is a term used for the most stable chemical conformation of a six membered single bonded carbon ring like cyclohexane. ... Cyclohexane conformation is a much studied topic in organic chemistry because of the complex interrelationship between the different conformers of cyclohexane and its derivatives. ...

Cyclohexane has the lowest angle and torsional strain of all the cycloalkanes, as a result cyclohexane has been deemed a 0 in total ring strain, a combination of angle and torsional strain. This also makes cyclohexane the most stable of the cycloalkanes and therefore will produce the least amount of heat when burned compared to the other cycloalkanes. Download high resolution version (935x456, 7 KB) Molecule structure of Cyclohexane, typeset with PPCHTeX. startchemical[] chemical [CHAIR,B,+R,-R, +RZ1,+RZ2,+RZ3,+RZ4,+RZ5,+RZ6, -RZ1,-RZ2,-RZ3,-RZ4,-RZ5,-RZ6] [H,H,H,H,H,H,H,H,H,H,H,H] stopchemical File links The following pages...

Reactions with cyclohexane

Pure cyclohexane in itself is rather unreactive, being a non-polar, hydrophobic hydrocarbon. It can react with very strong acids such as the superacid system HF + SbF₅ which will cause forced protonation and "hydrocarbon cracking". Substituted cyclohexane molecules are reactive to many different reactions, however, many which are important to organic chemistry. Fluoroantimonic acid HFSbF5 is a mixture of hydrogen fluoride and antimony pentafluoride in a various ratios. ...

Cyclohexane derivatives

The specific arrangement of functional groups in cyclohexane derivatives, and indeed in most cycloalkane molecules, is extremely important in chemical reactions, especially reactions involving nucleophiles. Substituents on the ring must be in the axial formation to react with other molecules. For example, the reaction of bromocyclohexane and a common nucleophile, a hydroxide anion (OH⁻), would result in cyclohexene: In organic chemistry, functional groups are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules. ... In chemistry, a nucleophile (literally nucleus lover) is a reagent which is attracted to centres of positive charge. ... A cyclohexane molecule in chair conformation, with hydrogen atoms in axial position in red, equatorial in blue. ... Hydroxide is a polyatomic ion consisting of oxygen and hydrogen: OH− It has a charge of −1. ... Cyclohexene is a colorless clear liquid cycloalkene with an intense aversive characteristic sharp smell reminiscent of an oil refinery. ...

C₆H₁₁Br + OH⁻ → C₆H₁₀ + H₂O + Br⁻

This reaction, commonly known as an elimination reaction or dehalogenation (specifically E2), requires that the bromine substituent be in the axial formation, opposing another axial H atom to react. Assuming that the bromocyclohexane was in the appropriate formation to react, the E2 reaction would commence as such: An elimination reaction is a type of organic reaction in which two substituents are removed from a molecule in either a one or two-step mechanism. ... General Name, Symbol, Number bromine, Br, 35 Chemical series halogens Group, Period, Block 17, 4, p Appearance gas/liquid: red-brown solid: metallic luster Atomic mass 79. ... In organic chemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon. ...

1. The electron pair bond between the C-Br moves to the Br, forming Br⁻ and setting it free from cyclohexane
2. The nucleophile (-OH) gives an electron pair to the adjacent axial H, setting H free and bonding to it to create H₂O
3. The electron pair bond between the adjacent axial H moves to the bond between the two C-C making it C=C

Note: All three steps happen simultaneously, characteristic of all E2 reactions.

The reaction above will generate mostly E2 reactions and as a result the product will be mostly (~70%) cyclohexene. However, the percentage varies with conditions, and generally, two different reactions (E2 and Sn2) compete. In the above reaction, an Sn2 reaction would substitute the bromine for a hydroxyl (OH^-) group instead, but once again, the Br must be in axial to react. Once the S_N2 substitution is complete, the newly substituted OH group would flip back to the more stable equatorial position quickly (~1 millisecond). Cyclohexene is a colorless clear liquid cycloalkene with an intense aversive characteristic sharp smell reminiscent of an oil refinery. ... In chemistry, nucleophilic substitution is a class of substitution reaction in which an electron-rich nucleophile attacks a molecule and replaces a group or atom, called the leaving group. ... // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ...

Cyclohexane in research

The usefulness of cyclohexane in research is not to be underestimated. Although much is already known about this cyclic hydrocarbon, research is still being done on cyclohexane and benzene mixtures and solid phase cyclohexane to determine hydrogen yields of the mix when irradiated at −195 °C.

History

Unlike compounds like benzene, cyclohexane cannot easily be obtained from natural resources such as coal. Towards the end of the nineteenth century early chemical investigators had to depend on organic synthesis. It took them 30 years to flesh out the details ^[1]. In 1867 Marcellin Berthelot reduced benzene with hydroiodic acid at elevated temperatures. He incorrectly identified the reaction product as n-hexane not only because of the convenient match in boiling point (69°C) but also because he did not believe benzene was a cyclic molecule (like his contemporary August Kekule) but rather some sort of association of acetylene. In 1870 one of his sceptics Adolf von Baeyer repeated the reaction and pronounced the same reaction product hexahydrobenzene and in 1890 Vladimir Markovnikov believed he was able to distill the same compound from Caucasus petroleum calling his concoction hexanaphtene Benzene, also known as benzol, is an organic chemical compound with the formula C6H6. ... Marcellin Berthelot Marcellin (or Marcelin) Pierre Eugène Berthelot (October 25, 1827 - March 18, 1907) was a French chemist and politician. ... Organic reductions or organic oxidations or organic redox reactions are redox reactions that take place with organic compounds. ... Benzene, also known as benzol, is an organic chemical compound with the formula C6H6. ... Hydroiodic acid (sometimes also spelled hydriodic acid) is a highly acidic aqueous solution of hydrogen iodide (HI) (Concentrated solution is usually 48 - 57% HI). ... R-phrases , , , , , , S-phrases , , , , , , , Flash point −23. ... The boiling point of a substance is the temperature at which it can change its state from a liquid to a gas throughout the bulk of the liquid at a given pressure. ... Friedrich August Kekul von Stradonitz (September 7, 1829 - July 13, 1896) was a German organic chemist. ... Acetylene (systematic name: ethyne) is the simplest alkyne hydrocarbon, consisting of two hydrogen atoms and two carbon atoms connected by a triple bond. ... Johann Friedrich Wilhelm Adolf von Baeyer (October 31, 1835 - August 20, 1917) was a German chemist who synthesized indigo, and was the 1905 recipient of the Nobel Prize in Chemistry . ... Vladimir Vasilevich Markovnikov (December 22, 1838 in Nizhny Novgorod - February 1904) was a Russian chemist. ... Pumpjack pumping an oil well near Lubbock, Texas Ignacy Łukasiewicz - inventor of the refining of kerosene from crude oil. ...

In 1894 Baeyer synthesized cyclohexane starting with a Dieckmann condensation of pimelic acid followed by multiple reductions: The Dieckmann condensation is the chemical reaction of diesters with base to give β-ketoesters. ... Pimelic acid, also heptanedioic acid, is a dicarboxylic acid, with formula C5H10(COOH)2. ...

and in the same year E. Haworth and W.H. Perkin Jr. (1860 - 1929) did the same in a Wurtz reaction of 1,6-dibromohexane. Image File history File links Size of this preview: 800 × 153 pixel Image in higher resolution (1050 × 201 pixel, file size: 5 KB, MIME type: image/png) Cyclohexane Baeyer Synthesis I, the creator of this work, hereby grant the permission to copy, distribute and/or modify this document under the... The Wurzt reaction after Charles Adolphe Wurtz is a coupling reaction in organic chemistry and organometallic chemistry where by two alkyl halides are reacted with sodium: 2 R-X + Na → R-R + 2NaX This reaction involves the radical species R.. References A. Wurtz, Ann. ...

Surprisingly their cyclohexanes boiled higher by 10°C than either hexahydrobenzene or hexanaphtene but this riddle was solved in 1895 by Markovnikov, N.M. Kishner and Nikolay Zelinsky when they re-diagnosed hexahydrobenzene and hexanaphtene as methylcyclopentane, the result of an unexpected rearrangement reaction. Image File history File links Size of this preview: 800 × 111 pixel Image in higher resolution (921 × 128 pixel, file size: 2 KB, MIME type: image/png) Cyclohexane synthesis Perkin / Haworth I, the creator of this work, hereby grant the permission to copy, distribute and/or modify this document under... Nikolay Zelinsky Nikolay Dimitrievich Zelinsky (Зелинский, Николай Дмитриевич in Russian) (February 6 n. ... Alkyl cycloalkanes are chemical compounds with an alkyl group with a single ring of carbons to which hydrogens are attached according to the formula CnH2n. ... A rearrangement reaction is a broad class of organic reactions where the carbon skeleton of a molecule is rearranged to give a structural isomer of the original molecule. ...

Image File history File links No higher resolution available. ...

See also

• The Flixborough disaster, a major industrial accident caused by an explosion of cyclohexane.
• Hexane

The Flixborough disaster was an explosion at a chemical plant close to Flixborough (near Scunthorpe), North Lincolnshire, UK, on 1 June 1974. ... the 3rd ingredient in big mac ...

External links

Wikimedia Commons has media related to:

Cyclohexane

• International Chemical Safety Card 0242
• National Pollutant Inventory - Cyclohexane fact sheet
• NIOSH Pocket Guide to Chemical Hazards
• Cyclohexane@3Dchem
• Links to external chemical sources
• NLM Hazardous Substances Databank – Cyclohexane

Image File history File links Commons-logo. ... Wikimedia Commons logo by Reid Beels The Wikimedia Commons (also called Commons or Wikicommons) is a repository of free content images, sound and other multimedia files. ...

References