Cyclohexane

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Cyclohexane
Image:Cyclohexane-structure3.png
General
Molecular formula	C₆H₁₂
SMILES	C1CCCCC1
Molar mass	84.16 g/mol
Appearance	Colorless liquid
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
Boiling point	80.74 °C
Viscosity	1.02 cP at 17 °C
Index of refraction, n_D	1.423
Thermodynamic data
Standard enthalpy of formation Δ_fH^o_liquid	-156 kJ/mol
Standard enthalpy of combustion Δ_cH^o_liquid	-3920 kJ/mol
Standard molar entropy S^o_liquid	? J.K⁻¹.mol⁻¹
Hazards
MSDS	External MSDS
EU classification	Flammable (F) Harmful (Xn) Dangerous for the environment (N)
NFPA 704	Image:Nfpa h1.png Image:Nfpa f3.png Image:Nfpa r0.png
R-phrases	Template:R11, Template:R38, Template:R65, Template:R67, Template:R50/53
S-phrases	Template:S2, Template:S9, Template:S16, Template:S25, Template:S33, Template:S60, Template:S61, Template:S62
Supplementary data page
Structure and properties	n, ε_r, 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
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 molecule with the molecular formula C₆H₁₂ (molar mass = 84.16g/mol) consisting of six carbon atoms linked to each other to form a ring, with each carbon atom bearing two hydrogen atoms. Cyclohexane is used as a solvent for the chemical industry mainly for the production of nylon. It can also be found in paints. Cyclohexane is a raw material for the industrial production of adipic acid.

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Chemical conformation

Template:Main

Due to the inherent need of the sp³ hybrid orbitals (and therefore the carbon-hydrogen bonds) on tetravalent carbons to reach 109.5°, cyclohexane is not a planar molecule. Chair and twist cyclohexanes exist with chair being the most stable, virtually strain free (111.5° C-C-C bond angles). Odd Hassel received the Nobel Prize for work on the conformations of cyclohexane.

In the lowest-energy chair conformation, half of the 12 hydrogens are in axial positions, which means their C-H bonds are parallel and appear to stick up and down from the structure, the other half are in equatorial positions; meaning that they are splayed out.

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