AskDefine | Define heptane

Dictionary Definition

heptane n : a colorless volatile highly flammable liquid obtained from petroleum and used as an anesthetic or a solvent or in determining octane ratings

User Contributed Dictionary

English

Noun

  1. Any of the nine isomers of the saturated aliphatic hydrocarbon C7H16, obtained from petroleum, especially n-heptane (CH3(CH2)5CH3)

Translations

saturated aliphatic hydrocarbon: C7H16
  • Italian: eptano
  • Swedish: heptan

Derived terms

Related terms

Extensive Definition

n-Heptane is the straight-chain alkane with the chemical formula H3C(CH2)5CH3 or C7H16. It is the zero point of the octane rating scale.

Uses

Heptane (and its many isomers) is widely applied in laboratories as a totally non-polar solvent. A liquid, it is ideal for transport and storage. In the grease spot test, heptane is used to dissolve the oil spot to show the previous presence of organic compounds on a stained paper. This is done by shaking the stained paper in a heptane solution for about half a minute.
Extraction into heptane is a means by which aqueous bromine may be distingiushed from aqueous iodine. In water, both bromine and iodine appear brown. However, iodine turns purple when dissolved in heptane, whereas the bromine solution remains brown.
Heptane is commercially available as the rubber cement solvent Bestine.

Octane rating scale

n-Heptane is the zero point of the octane rating scale. It is undesirable in petrol, because it burns explosively, causing engine knocking, as opposed to branched-chain octane isomers, which burn more slowly and give better performance. It was chosen as the zero point of the scale because of the availability of very high purity n-heptane, unmixed with other isomers of heptane or other alkanes, distilled from the resin of Jeffrey Pine and from the fruit of Pittosporum resiniferum. Other sources of heptane and octane, produced from crude oil, contain a mixture of different isomers with greatly differing ratings and do not give as precise a zero point.

Isomers and enantiomers

Heptane has nine isomers, or eleven if enantiomers are counted:
  • Heptane (n-heptane), H3C–CH2–CH2–CH2–CH2–CH2–CH3, straight chain of seven carbon atoms.
  • 2-Methylhexane, H3C–CH(CH3)–CH2–CH2–CH2–CH3, chain of six carbon atoms, and a methyl group attached to the second.
  • 3-Methylhexane, H3C–CH2–C*H(CH3)–CH2–CH2–CH3 (chiral), chain of six carbon atoms, and a methyl group attached to the third.
  • 2,2-Dimethylpentane, (H3C)3–C–CH2–CH2–CH3, chain of five carbon atoms, and two methyl groups attached to the second.
  • 2,3-Dimethylpentane, (H3C)2–CH–C*H(CH3)–CH2–CH3 (chiral), chain of five carbon atoms, and methyl groups attached to the second and third.
  • 2,4-Dimethylpentane, (H3C)2–CH–CH2–CH–(CH3)2, chain of five carbon atoms, and methyl groups attached to the second and fourth.
  • 3,3-Dimethylpentane, H3C–CH2C(CH3)2–CH2–CH3, chain of five carbon atoms, and two methyl groups attached to the third.
  • 3-Ethylpentane, H3C–CH2–CH(CH2CH3)–CH2–CH3, chain of five carbons, and an ethyl group attached to the third.
  • 2,2,3-Trimethylbutane, (H3C)3–CH(CH3)–CH3, chain of four carbon atoms, with two methyl groups attached to the second, and one to the third.http://members.optushome.com.au/scottsoftb/skeletons3.htm
heptane in Arabic: هيبتان
heptane in Bosnian: Heptan
heptane in Catalan: Heptà
heptane in Czech: Heptan
heptane in German: Heptan
heptane in Estonian: Heptaan
heptane in Spanish: Heptano
heptane in Esperanto: Heptano
heptane in French: Heptane
heptane in Italian: Eptano
heptane in Kurdish: Heptan
heptane in Latvian: Heptāns
heptane in Hungarian: Heptán
heptane in Dutch: Heptaan
heptane in Japanese: ヘプタン
heptane in Norwegian: Heptan
heptane in Polish: Heptan
heptane in Portuguese: Heptano
heptane in Russian: Гептан
heptane in Serbian: Хептан
heptane in Finnish: Heptaani
heptane in Swedish: Heptan
heptane in Vietnamese: Heptan
heptane in Chinese: 庚烷
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