Cyclohexane is a cycloalkane Cycloalkanes are types of alkanes which have one or more rings of carbon atoms in the chemical structure of their molecules. Alkanes are types of organic hydrocarbon compounds which have only single chemical bonds in their chemical structure. Cycloalkanes consist of only carbon (C) and hydrogen (H) atoms and are saturated because there are no with the molecular formula A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound C Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of₆H Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of 1.00794 u (1.007825 u for Hydrogen-1), hydrogen is the lightest and most abundant chemical element, constituting roughly 75 % of the Universe's elemental mass. Stars in the main sequence are mainly composed of hydrogen in its₁₂. Cyclohexane is used as a nonpolar In chemistry, polarity refers to a separation of electric charge leading to a molecule having an electric dipole. Polar molecules can bond together due to dipole–dipole intermolecular forces between one molecule with asymmetrical charge distribution and another molecule also with asymmetrical charge distribution. Molecular polarity is dependent solvent A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature. Common uses for organic solvents are in dry cleaning (e.g. tetrachloroethylene), as a paint thinner (e.g. toluene, turpentine), as nail polish removers and for the chemical industry, and also as a raw material for the industrial production of adipic acid Adipic acid is the organic compound with the formula 4(COOH)2. From the industrial perspective, it is the most important dicarboxylic acid: About 2.5 billion kilograms of this white crystalline powder are produced annually, mainly as a precursor for the production of nylon. Adipic acid otherwise rarely occurs in nature and caprolactam Caprolactam is an organic compound with the formula 5C(O)NH. This colourless solid, which is a lactam or a cyclic amide of caproic acid. Approximately 2 billion kilograms are produced annually. Caprolactam is the precursor to Nylon 6, a widely used synthetic polymer, both of which are intermediates used in the production of nylon Nylon is a generic designation for a family of synthetic polymers known generically as polyamides, first produced on February 28, 1935 by Wallace Carothers at DuPont's research facility at the DuPont Experimental Station. Nylon is one of the most commonly used polymers. On an industrial scale, cyclohexane is produced by reacting benzene Benzene is an organic chemical compound 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 it is a known carcinogen, its use as an additive in gasoline is now limited, but it is an important industrial solvent and with hydrogen Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of 1.00794 u (1.007825 u for Hydrogen-1), hydrogen is the lightest and most abundant chemical element, constituting roughly 75 % of the Universe's elemental mass. Stars in the main sequence are mainly composed of hydrogen in its. Due to its unique chemical and conformational properties, cyclohexane is also used in labs in analysis and as a standard.

Chemical conformation

The 6 vertexed ring does not conform to the shape of a perfect hexagon In geometry, a hexagon is a polygon with six edges and six vertices. A regular hexagon has Schläfli symbol {6}. The total of the internal angles of any hexagon is 720 degrees. The conformation of a flat 2D planar hexagon has considerable angle strain because its bonds are not 109.5 degrees; the torsional strain would also be considerable due to all eclipsed bonds In chemistry an eclipsed conformation is a conformation in which two substituents X and Y on adjacent atoms A, B are in closest proximity, implying that the torsion angle X-A-B-Y is 0°. Such a conformation exists in any open chain single chemical bond connecting two sp3 hybridised atoms, and is normally a conformational energy maximum. This. Therefore, to reduce torsional strain In general, the displacement of a continuum body has two components: a rigid-body displacement component and a deformation component. If after a displacement of the continuum there is a relative displacement between particles, a deformation has occurred. On the other hand, if after displacement of the continuum the relative displacement between, cyclohexane adopts a three-dimensional structure known as the chair conformation. This was first proposed as early as 1890 by Hermann Sachse, but only gained widespread acceptance much later. The new conformation puts the carbons at an angle of 109.5°. Half of the hydrogens are in the plane of the ring (equatorial) while the other half are perpendicular to the plane (axial). This conformation allows for the most stable structure of cyclohexane. Another conformation of cyclohexane exists, known as boat conformation Cyclohexane conformation is a much studied topic in organic chemistry because of the complex interrelationship between the different conformers of cyclohexane and its derivatives. Different conformers may have differing properties, including stability and chemical reactivity, but it interconverts to the slightly more stable chair formation. If cyclohexane is mono-substituted with a large substituent In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon. The terms substituent, side chain, group, branch, or pendant group are used almost interchangeably to describe branches from a parent structure, though certain distinctions are made in the, then the substituent will most likely be found attached in an equatorial position, as this is the slightly more stable conformation.

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 (per CH₂ unit) when burned compared to the other cycloalkanes.

Reactions

Pure cyclohexane in itself is rather unreactive, being a non-polar, hydrophobic In chemistry, hydrophobicity is the physical property of a molecule (known as a hydrophobe) that is repelled from a mass of water hydrocarbon. It can react with very strong acids such as the superacid A superacid is an acid with an acidity greater than that of 100% pure sulfuric acid, which has a Hammett acidity function of −12. Commercially available superacids include trifluoromethanesulfonic acid (CF3SO3H), also known as triflic acid, and fluorosulfonic acid (FSO3H), both of which are about a thousand times stronger (i.e. have more system HF + SbF₅ Fluoroantimonic acid HSbF6 is a mixture of hydrogen fluoride and antimony pentafluoride in various ratios. The 1:1 combination affords the strongest known superacid, which has been demonstrated to protonate even hydrocarbons to afford carbocations and H2 which will cause forced protonation and "hydrocarbon cracking". Substituted cyclohexanes, however, may be reactive under a variety of conditions, many of which are important to organic chemistry. Cyclohexane is highly flammable.

Derivatives

The specific arrangement of functional groups In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of. However, its relative reactivity can be 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 Cyclohexane conformation is a much studied topic in organic chemistry because of the complex interrelationship between the different conformers of cyclohexane and its derivatives. Different conformers may have differing properties, including stability and chemical reactivity formation to react with other molecules. For example, the reaction of bromocyclohexane and a common nucleophile, a hydroxide In chemistry, hydroxide is the name for the diatomic anion OH−, consisting of covalently bonded oxygen and hydrogen atoms, usually derived from the dissociation of a base. It is one of the simplest and most pervasive diatomic ions known anion (OH⁻), would result in cyclohexene Cyclohexene is a hydrocarbon with the formula C6H10. This cycloalkene is a colorless liquid with a sharp smell. It is an intermediate in various industrial processes. Cyclohexene is not very stable upon long term storage with exposure to light and air because it forms peroxides:

C₆H₁₁Br + OH⁻ → C₆H₁₀ + H₂O + Br⁻

This reaction, commonly known as an elimination reaction 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 . Either the unsaturation of the molecule increases or the valence of an atom in the molecule decreases by two, a process known as reductive elimination or dehalogenation Halogenation is a chemical reaction that incorporates a halogen atom into a molecule. More specific descriptions exist that specify the type of halogen: fluorination, chlorination, bromination, and iodination (specifically E2), requires that the bromine Bromine (pronounced /ˈbroʊmiːn/ BROH-meen or /ˈbroʊmɨn/ BROH-min; from Greek: βρῶμος, brómos, meaning "stench "), is a chemical element with the symbol Br and atomic number 35. A halogen element, it is, along with mercury, the only strictly liquid element at room temperature, but cesium, rubidium, francium and gallium are substituent In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon. The terms substituent, side chain, group, branch, or pendant group are used almost interchangeably to describe branches from a parent structure, though certain distinctions are made in the 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:

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 Cyclohexene is a hydrocarbon with the formula C6H10. This cycloalkene is a colorless liquid with a sharp smell. It is an intermediate in various industrial processes. Cyclohexene is not very stable upon long term storage with exposure to light and air because it forms peroxides. However, the percentage varies with conditions, and generally, two different reactions (E2 and S_N2 In organic and inorganic chemistry, nucleophilic substitution is a fundamental class of substitution reaction in which an "electron rich" nucleophile selectively bonds with or attacks the positive or partially positive charge of an atom attached to a group or atom called the leaving group; the positive or partially positive atom is) compete. In the above reaction, an S_N2 reaction would substitute the bromine for a hydroxyl In chemistry, hydroxyl is a compound containing an oxygen atom bound covalently with a hydrogen atom. The neutral form of this group is a hydroxyl radical. The hydroxyl anion is called hydroxide; it is a diatomic ion with a single negative electronic charge. In discussions of synthetic methods in organic chemistry the hydroxyl group (–OH) is (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).

Uses

Commercially most of cyclohexane produced is converted into cyclohexanone Cyclohexanone is the organic compound with the formula 5CO. The molecule consists of six-carbon cyclic molecule with a ketone functional group. This colorless oil has an odor reminiscent of peardrop sweets as well as acetone. Over time, samples assume a yellow color due to oxidation. Cyclohexanone is slightly soluble in water (5-10 g/100 mL), but-cyclohexanol Cyclohexanol is the organic compound with the formula (C mixture (or "KA oil") by catalytic oxidation. KA oil is then used as a raw material for adipic acid Adipic acid is the organic compound with the formula 4(COOH)2. From the industrial perspective, it is the most important dicarboxylic acid: About 2.5 billion kilograms of this white crystalline powder are produced annually, mainly as a precursor for the production of nylon. Adipic acid otherwise rarely occurs in nature and caprolactam Caprolactam is an organic compound with the formula 5C(O)NH. This colourless solid, which is a lactam or a cyclic amide of caproic acid. Approximately 2 billion kilograms are produced annually. Caprolactam is the precursor to Nylon 6, a widely used synthetic polymer. Practically, if the cyclohexanol content of KA oil is higher than cyclohexanone, it is more likely(economical) to be converted into adipic acid, and the reverse case, caprolactam production is more likely. Such ratio in KA oil can be controlled by selecting suitable oxidation catalyst. Some of cyclohexane is used as an organic solvent.

Although much is already known about this cyclic hydrocarbon, research is still being done on cyclohexane and benzene Benzene is an organic chemical compound 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 it is a known carcinogen, its use as an additive in gasoline is now limited, but it is an important industrial solvent and mixtures and solid phase cyclohexane to determine hydrogen yields of the mix when irradiated at −195 °C.

Cyclohexane is also used for calibration of Differential scanning calorimetry Differential scanning calorimetry or DSC is a thermoanalytical technique in which the difference in the amount of heat required to increase the temperature of a sample and reference is measured as a function of temperature. Both the sample and reference are maintained at nearly the same temperature throughout the experiment. Generally, the (DSC) instruments, because of a convenient crystal-crystal transition at -87.1 C. ^[1]

Heat treating equipment manufacturer Surface Combustion uses cyclohexane as a carbon carrying gas in their high purity vacuum carburizing furnaces.

History

Unlike compounds like benzene Benzene is an organic chemical compound 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 it is a known carcinogen, its use as an additive in gasoline is now limited, but it is an important industrial solvent and, 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^[2]. In 1867 Marcellin Berthelot Marcellin Pierre Eugène Berthelot (25 October 1827 – 18 March 1907) was a French chemist and politician noted for the Thomsen-Berthelot principle of thermochemistry . He synthesized many organic compounds from inorganic substances and disproved the theory of vitalism. He is considered as one of the greatest chemists of all time reduced Organic reductions or organic oxidations or organic redox reactions are redox reactions that take place with organic compounds. In organic chemistry oxidations and reductions are different from ordinary redox reactions because many reactions carry the name but do not actually involve electron transfer in the electrochemical sense of the word benzene Benzene is an organic chemical compound 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 it is a known carcinogen, its use as an additive in gasoline is now limited, but it is an important industrial solvent and with hydroiodic acid Hydrogen iodide is a diatomic molecule. Aqueous solutions of HI are known as iohydroic acid or hydriodic acid, a strong acid. Hydrogen iodide and hydroiodic acid are, however, different in that the former is a gas under standard conditions; whereas, the other is an aqueous solution of said gas. They are interconvertible. HI is used in organic and at elevated temperatures. He incorrectly identified the reaction product as n-hexane Hexane is a hydrocarbon with the chemical formula C6H14; that is, an alkane with six carbon atoms not only because of the convenient match in boiling point The boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid (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 Acetylene is the chemical compound with the formula HC2H. It is a hydrocarbon and the simplest alkyne. This colourless gas is widely used as a fuel and a chemical building block. It is unstable in pure form and thus is usually handled as a solution. In 1870 one of his sceptics Adolf von Baeyer Johann Friedrich Wilhelm Adolf von Baeyer was a German chemist who synthesized indigo, and was the 1905 recipient of the Nobel Prize in Chemistry. Born in Berlin, he initially studied mathematics and physics at Berlin University before moving to Heidelberg to study chemistry with Robert Bunsen. There he worked primarily in August Kekulé's repeated the reaction and pronounced the same reaction product hexahydrobenzene and in 1890 Vladimir Markovnikov Vladimir Vasilyevich Markovnikov , also spelled as Markownikoff (December 22, 1838 in Nizhny Novgorod - February 11, 1904) was a Russian chemist believed he was able to distill the same compound from Caucasus petroleum Petroleum or crude oil is a naturally occurring, toxic, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights, and other organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling. It is refined and separated, most easily by calling his concoction hexanaphtene

In 1894 Baeyer synthesized cyclohexane starting with a Dieckmann condensation The Dieckmann condensation is the intramolecular chemical reaction of diesters with base to give β-ketoesters. It is named after the German chemist Walter Dieckmann . The equivalent intermolecular reaction is the Claisen condensation of pimelic acid Pimelic acid is the organic compound with the formula HO2C5CO2H. Derivatives of pimelic acid are involved in the biosynthesis of the amino acid called lysine. Pimelic acid is one methylene longer than a related dicarboxylic acid, adipic acid, a precursor to many polyesters and polyamides. It is the final member of the mnemonic used to aid followed by multiple reductions:

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.

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.

See also

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

References

1. ^ D. M. Price. Temperature Calibration of Differential Scanning Calirimeters. Journal of Thermal Analysis, Vol. 45 (1995) 1285-1296
2. ^ The curiously intertwined histories of benzene and cyclohexane E.W. Warnhoff J. Chem. Ed., 1996 494

External links

• International Chemical Safety Card 0242
• National Pollutant Inventory - Cyclohexane fact sheet
• NIOSH Pocket Guide to Chemical Hazards
• Cyclohexane@3Dchem
• Hermann Sachse and the first suggestion of a chair conformation.
• NLM Hazardous Substances Databank – Cyclohexane
• Methanol Discovered in Space
• Calculation of vapor pressure, liquid density, dynamic liquid viscosity, surface tension of cyclohexane

Categories: Cycloalkanes | Hydrocarbon solvents

Personal tools

• New features
• Log in / create account

Namespaces

• Article
• Discussion

Variants

Views

• Read
• Edit
• View history

Actions

Search

Navigation

• Main page
• Contents
• Featured content
• Current events
• Random article

Interaction

• About Wikipedia
• Community portal
• Recent changes
• Contact Wikipedia
• Donate to Wikipedia
• Help

Toolbox

• What links here
• Related changes
• Upload file
• Special pages
• Permanent link
• Cite this page

Print/export

• Create a book
• Download as PDF
• Printable version

Languages

• العربية
• Български
• Català
• Česky
• Dansk
• Deutsch
• Español
• Français
• Italiano
• עברית
• Magyar
• Nederlands
• 日本語
• ‪Norsk (bokmål)‬
• ‪Norsk (nynorsk)‬
• Polski
• Português
• Русский
• Suomi
• Svenska
• Tiếng Việt
• 中文

• This page was last modified on 18 May 2010 at 14:33.
• Text is available under the Creative Commons Attribution-ShareAlike License ; additional terms may apply. See Terms of Use for details.
  Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
• Contact us

• Privacy policy
• About Wikipedia
• Disclaimers

See Also:

• Cyclohexane: Encyclopedia

What Links Here:

Recently Viewed Pages:

• Petrochemicals: News
• Search Terms
• Home
• About Us
• Referrers
• Ethylbenzene: Answers
• Phthalic Anhydride: Answers
• Terephthalic Acid: Encyclopedia
• 2-Ethylhexanol
• Polyethylene Terephthalate: Encyclopedia

Most Popular Pages:

• What Is A1h1 Virus: News
• A1h1 Virus Symptoms: News
• Search Terms
• Home
• Isopropyl Alcohol: Encyclopedia
• What Is the Monomer of a Lipid?: Answers
• Sumitomo: Answers
• Cyclohexane: Web Search
• Hexene: Answers
• Petroleum

Related 'Cyclohexane' Searches: