Cycloheptane

Cycloheptane

Names
Preferred IUPAC name Cycloheptane
Identifiers
CAS Number	291-64-5  Y
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL453194  Y
ChemSpider	8908  Y
ECHA InfoCard	100.005.483
EC Number	206-030-2
PubChem CID	9265
UNII	VTZ53P34JA  Y
UN number	2241
CompTox Dashboard (EPA)	DTXSID0074269
InChI InChI=1S/C7H14/c1-2-4-6-7-5-3-1/h1-7H2 Y Key: DMEGYFMYUHOHGS-UHFFFAOYSA-N Y InChI=1/C7H14/c1-2-4-6-7-5-3-1/h1-7H2 Key: DMEGYFMYUHOHGS-UHFFFAOYAF
SMILES C1CCCCCC1
Properties
Chemical formula	C7H14
Molar mass	98.189 g·mol−1
Appearance	colorless oily liquid
Density	0.8110 g/cm3
Melting point	−12 °C (10 °F; 261 K)
Boiling point	118.4 °C (245.1 °F; 391.5 K)
Solubility in water	negligible
Solubility	very soluble in ethanol, ether soluble in benzene, chloroform
log P	4.0
Refractive index (nD)	1.4436
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H225, H304, H412
Precautionary statements	P210, P233, P240, P241, P242, P243, P273, P280, P301+P310, P303+P361+P353, P331, P370+P378, P403+P235, P405, P501
NFPA 704 (fire diamond)	1 3 0
Flash point	6 °C (43 °F; 279 K)
Related compounds
Related cycloalkanes	Cyclohexane Cyclooctane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y  verify  (what is  YN ?) Infobox references

Cycloheptane, also known as Suberane, ^[1] is an organic compound, which belongs to the group of cycloalkanes. The compound can occur in different conformers.

Production

Cycloheptane occurs naturally in petroleum and can be extracted from it. It is synthesized by a Clemmensen reduction from cycloheptanone. ^[2]

Properties

Cycloheptane is a colorless liquid with a mild, aromatic odor. The boiling point at normal pressure is 119°C. ^[3] The molar enthalpy of vaporization is 38.5 kJ mol⁻¹. ^[4] According to the Antoine equation, the vapor pressure function is given by log₁₀(P) = A−(B/(T+C)) (P in bar, T in K) with A = 3,97710, B = 1330,402 and C = −56,946 in the temperature range from 341.3 K to 432.2 K. ^[4]

In the solid phase, cycloheptane occurs in four polymorphic forms. ^{[4] [5]} The transformation temperatures for the conversion from form IV to form III are −138°C, from form III to form II −75°C and from form II to form I −61°C. ^[4] Form I melts at −8°C. ^{[4] [3]}

Compilation of the most important thermodynamic properties

Property	Type	Value [Unit]	Note
Standard enthalpy of formation	ΔfH0liquid	−156,4 kJ·mol−1 [6]
Standard entropy	S0liquid	242,55 J·mol−1·K−1 [4]	as a liquid
Heat of combustion	ΔcH0liquid	−4598,9 kJ·mol−1 [6]
Heat capacity	cp	180,614 J·mol−1·K−1 (25 °C) [7] 132,0 J·mol−1·K−1 (25 °C) [8]	as a liquid as a gas
Triple point	Ttriple	265,12 K [4]
Critical temperature	Tc	604,2 K [9]
Critical pressure	pc	38,2 bar [9]
Critical volume	Vc	0.353 l·mol−1 [9]
Critical density	ρc	2,83 mol·l−1 [9]

Chemical properties

Cycloheptane can be thermally rearranged to methylcyclohexane in the presence of aluminum trichloride.

Functionalization can be achieved by chlorination with N-chlorosuccinimide. ^[10]

The compound is flammable and forms flammable vapour-air mixtures with air. ^[3] The flash point is 6 °C, the lower explosion limit is 1.1 vol.%. ^[3]

Usage

Cycloheptane can be used as a non-polar solvent. In organic synthesis, the cycloheptyl functional groups can be introduced into organic molecules, e.g. pharmaceutical active ingredients, after functionalization.

Hazards

An irritating effect on the eyes and respiratory tract is mentioned in the literature. The toxic effect is more comparable to that of methylcyclohexane, which only slightly irritates the mucous membranes. Animal experiments showed only a slight irritating effect on the skin. Systemically, cycloheptane has a depressant effect on the central nervous system. ^[3]

Further reading

• Dragojlovic, V. (2015). "Conformational analysis of cycloalkanes". ChemTexts. 1 (14). Bibcode:2015ChTxt...1...14D. doi:10.1007/s40828-015-0014-0 . Retrieved 3 December 2024.
• Reusch, William (2008) [1999]. "Ch. 5. Saturated Hydrocarbons—Alkanes and Cycloalkanes". An Introduction to Organic Chemistry. East Lansing, MI: William Reusch and Michigan State University. Retrieved 3 December 2024.
• Bocian, D. F.; Pickett, H. M.; Rounds, Thomas C.; Strauss, Herbert L. (1975). "Conformations of cycloheptane". Journal of the American Chemical Society. 97 (4): 687–695. doi:10.1021/ja00837a001. ISSN   0002-7863.

References

1. "DNB, Katalog der Deutschen Nationalbibliothek" (in German). Deutsche Nationalbibliothek. 2024-12-06. Retrieved 2025-02-06.
2. Communications, EBCONT. "Cycloheptan". RÖMPP, Thieme (in German). Retrieved 2025-02-05.
3. "Cycloheptan". gestis.dguv.de. Retrieved 2025-02-05.
4. Finke, H. L.; Scott, D. W.; Gross, M. E.; Messerly, J. F.; Waddington, Guy (1956). "Cycloheptane, Cycloöctane and 1,3,5-Cycloheptatriene. Low Temperature Thermal Properties, Vapor Pressure and Derived Chemical Thermodynamic Properties". Journal of the American Chemical Society. 78 (21): 5469–5476. doi:10.1021/ja01602a003. ISSN   0002-7863.
5. Domalski, Eugene S.; Hearing, Elizabeth D. (1996-01-01). "Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III" (PDF). Journal of Physical and Chemical Reference Data. 25 (1): 1. doi: 10.1063/1.555985 . ISSN   0047-2689 . Retrieved 2025-02-05.
6. Spitzer, Ralph; Huffman, Hugh M. (1947). "The Heats of Combustion of Cyclopentane, Cyclohexane, Cycloheptane and Cyclooctane". Journal of the American Chemical Society. 69 (2): 211–213. doi:10.1021/ja01194a006. ISSN   0002-7863. PMID   20292425.
7. Fortier, Jean-Luc; D'arcy, Patrick J.; Benson, George C. (1979). "Heat capacities of binary cycloalkane mixtures at 298.15 K". Thermochimica Acta. 28 (1). Elsevier BV: 37–43. doi:10.1016/0040-6031(79)87005-7. ISSN   0040-6031.
8. Dorofeeva, O. V.; Gurvich, L. V.; Jorish, V. S. (1986-04-01). "Thermodynamic Properties of Twenty-One Monocyclic Hydrocarbons". Journal of Physical and Chemical Reference Data. 15 (2): 437–464. doi:10.1063/1.555773. ISSN   0047-2689.
9. Daubert, Thomas E. (1996-01-01). "Vapor−Liquid Critical Properties of Elements and Compounds. 5. Branched Alkanes and Cycloalkanes". Journal of Chemical & Engineering Data. 41 (3): 365–372. doi:10.1021/je9501548. ISSN   0021-9568.
10. Buu-Hoï, Ng. Ph.; Demerseman, P. (1953). "Halogenation of Saturated Compounds with N-Chloro-And N-Bromo-Succinimide". The Journal of Organic Chemistry. 18 (6): 649–652. doi:10.1021/jo01134a005. ISSN   0022-3263.