Cycloheptane

Cycloheptane
Skeletal formula
Ball-and-stick model
Names
Preferred IUPAC name
Cycloheptane
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.005.483 Edit this at Wikidata
EC Number
  • 206-030-2
UNII
UN number 2241
  • InChI=1S/C7H14/c1-2-4-6-7-5-3-1/h1-7H2 checkY
    Key: DMEGYFMYUHOHGS-UHFFFAOYSA-N checkY
  • InChI=1/C7H14/c1-2-4-6-7-5-3-1/h1-7H2
    Key: DMEGYFMYUHOHGS-UHFFFAOYAF
  • C1CCCCCC1
Properties
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)
negligible
Solubility very soluble in ethanol, ether
soluble in benzene, chloroform
log P 4.0
1.4436
Hazards
GHS labelling:
GHS02: FlammableGHS08: Health hazard
Danger
H225, H304, H412
P210, P233, P240, P241, P242, P243, P273, P280, P301+P310, P303+P361+P353, P331, P370+P378, P403+P235, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 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. gasolineInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
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).
checkY verify (what is checkY☒N ?)

Cycloheptane, synonym suberane, is a cycloalkane[citation needed] with the molecular formula C7H14.[1] It is a poorly water soluble organic liquid (melting point –12 deg C, solubility in water <30 mg /liter at 25 deg C),[1] and is used as a nonpolar solvent for the chemical industry and as an intermediate in the manufacture of chemicals and pharmaceutical drugs.[not verified in body] It can be prepared by Clemmensen reduction from cycloheptanone.[not verified in body] Cycloheptane vapour is irritating to the eyes and may cause respiratory depression if inhaled in large quantity.[not verified in body]

Conformations

Cycloheptane is not a flat molecule, because that would give C-C-C bond angles much greater than the tetrahedral angle of around 109.5°. Instead it is puckered and three-dimensional. One can ask the question of what conformations would have the same angle everywhere (near 109.5°) and all bond lengths equal. If we think of an open chain of seven bonds, there are five dihedral angles that can be chosen, for the sequences (1,2,3,4), (2,3,4,5), and so on. The last bond though should end where the first began, and should form the correct angle with the first bond. This imposes four constraints, but we have five dihedral angles to play with, so there is one degree of freedom. It turns out that there are two continua of solutions. One is a circular series of fourteen "boat" conformations interspersed with "twist-boat" conformations, and the other is a circular series of fourteen "chair" conformations interspersed with "twist-chair" conformations. The boat and chair conformations have mirror symmetry, while the twist-boat and twist-chair have two-fold rotational symmetry. Conformations between boat and twist-boat or between chair and twist-chair have no symmetry. The passage along the continuum boat→twist-boat→boat→twist-boat→boat constitutes a pseudorotation, as does chair→twist-chair→chair→twist-chair→chair. Below are depicted the boat and chair conformations.[2][better source needed]

  • Boat
    Boat
  • Chair
    Chair

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.

References

  1. ^ a b Mackay, Donald; Shiu, Wan-Ying; Ma, Kuo-Ching & Lee, Sum Chi (2006). Handbook of Physical-chemical Properties and Environmental Fate for Organic Chemicals (2nd, illus., rev. ed.). Boca Raton, FL: CRC Press. pp. 254–257. ISBN 9781420044393. Retrieved 3 December 2024.{{cite book}}: CS1 maint: multiple names: authors list (link)
  2. ^ Bocian, D. F.; Pickett, H. M.; Rounds, T. C.; Strauss, H. L. (1975). "Conformations of cycloheptane". Journal of the American Chemical Society. 97 (4): 687–695. Bibcode:1975JAChS..97..687B. doi:10.1021/ja00837a001. ISSN 0002-7863. Retrieved 3 December 2024.[non-primary source needed]
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