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Cyclohexyl

Cyclohexane
Cyclohexane
3D structure of a cyclohexane molecule
Skeletal formula of cyclohexane in its chair conformation
Ball-and-stick model of cyclohexane in its chair conformation
Names
Preferred IUPAC name
Cyclohexane
Other names
Hexanaphthene
Identifiers
110-82-7 YesY
3D model (Jmol) Interactive image
ChEBI CHEBI:29005 YesY
ChEMBL ChEMBL15980 YesY
ChemSpider 7787 YesY
DrugBank DB03561 YesY
ECHA InfoCard 100.003.461
KEGG C11249 YesY
PubChem 8078
UNII 48K5MKG32S YesY
Properties
C6H12
Molar mass 84.16 g·mol−1
Appearance Colorless liquid
Odor Sweet, gasoline-like
Density 0.7781 g/mL, liquid
Melting point 6.47 °C (43.65 °F; 279.62 K)
Boiling point 80.74 °C (177.33 °F; 353.89 K)
Immiscible
Solubility Soluble in ether, alcohol, acetone
Miscible with olive oil
Vapor pressure 78 mmHg (20 °C)
-68.13·10−6 cm3/mol
1.42662
Viscosity 1.02 cP at 17 °C
Thermochemistry
-156 kJ/mol
-3920 kJ/mol
Hazards
Safety data sheet See: data page
Highly Flammable F Harmful Xn Dangerous for the Environment (Nature) N
R-phrases R11, R38, R65, R67, R50/53
S-phrases (S2), S9, S16, S25, S33, S60, S61, S62
NFPA 704
Flammability code 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g., gasoline) Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point −20 °C (−4 °F; 253 K)
245 °C (473 °F; 518 K)
Explosive limits 1.3%-8%
Lethal dose or concentration (LD, LC):
LD50 (median dose)
12705 mg/kg (rat, oral)
813 mg/kg (mouse, oral)
17,142 ppm (mouse, 2 hr)
26,600 ppm (rabbit, 1 hr)
US health exposure limits (NIOSH):
PEL (Permissible)
TWA 300 ppm (1050 mg/m3)
REL (Recommended)
TWA 300 ppm (1050 mg/m3)
IDLH (Immediate danger)
1300 ppm
Related compounds
Related cycloalkanes
Cyclopentane
Cycloheptane
Related compounds
Cyclohexene
Benzene
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Thermodynamic
data
Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY  (what is YesYN ?)
Infobox references

Cyclohexane is a cycloalkane with the molecular formula C6H12 (abbreviated to Cy). Cyclohexane is mainly used for the industrial production of adipic acid and caprolactam, which are precursors to nylon. Cyclohexane is a colourless, flammable liquid with a distinctive detergent-like odor, reminiscent of cleaning products (in which it is sometimes used).

On an industrial scale, cyclohexane is produced by hydrogenation of benzene. Producers of cyclohexane accounts for approximately 11.4% of global demand for benzene. The reaction is highly exothermic, with ΔH(500 K) = 216.37 kJ/mol). Dehydrogenation commenced noticeably above 300 °C, reflecting the favorable entropy for dehydrogenation.

Unlike benzene, cyclohexane is not easily obtained from natural resources such as coal. For this reason, early investigators synthesized their cyclohexane samples.

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 reassigned "hexahydrobenzene" and "hexanaphtene" as methylcyclopentane, the result of an unexpected rearrangement reaction.

In 1894 Baeyer synthesized cyclohexane starting with a Dieckmann condensation of pimelic acid followed by multiple reductions:

In the same year E. Haworth and W.H. Perkin Jr. (1860–1929) prepared it via a Wurtz reaction of 1,6-dibromohexane.

Cyclohexane is rather unreactive, being a non-polar, hydrophobic hydrocarbon. It reacts with superacids, such as HF + SbF5, which will lead to cracking. Substituted cyclohexanes, however, may be reactive under a variety of conditions, many of which are important in organic chemistry.


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Wikipedia

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